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Computer simulation of overseas product manufacturing potentials of a redesigned multipass headrig mill… Orbay, Laszlo 1984

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COMPUTER SIMULATION OF OVERSEAS PRODUCT MANUFACTURING POTENTIALS OF A REDESIGNED MULTIPASS HEADRIG MILL IN COASTAL BRITISH COLUMBIA  by  LASZLO ORBAY DIPL.WOOD IND.ENG.,UNIVERSITY OF SOPRON, 1966 DIPL.BUS.ADM.,UNIVERSITY OF ECONOMICS, BUDAPEST, 1974  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE  REQUIREMENTS  FOR THE DEGREE OF  DOCTOR OF PHILOSOPHY in THE  FACULTY OF GRADUATE STUDIES DEPARTMENT  We a c c e p t to  THE  this  OF FORESTRY  thesis  the required  as  standard  UNIVERSITY OF BRITISH JUNE  ©  conforming  COLUMBIA  1984  LASZLO ORBAY, 1984  'E-6  In p r e s e n t i n g  t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the  requirements f o r an advanced degree a t the U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make it  f r e e l y a v a i l a b l e f o r reference  agree t h a t p e r m i s s i o n  and study.  f o r extensive  I further  copying o f t h i s t h e s i s  f o r s c h o l a r l y purposes may be granted by t h e head o f my department o r by h i s o r her r e p r e s e n t a t i v e s .  It is  understood t h a t copying o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be allowed w i t h o u t my w r i t t e n permission.  Department  Of  Forest  Recorces  The U n i v e r s i t y o f B r i t i s h 1956 Main Mall Vancouver, Canada V6T 1Y3  (3/81)  Management.  Columbia  Faculty  of  Forestry  ABSTRACT  Modification Ltd.,  at.  of  Harmac  the  became  operation.  The  flexibility  in serving  Stochastic reconstruction new  computer  evaluate model, affect Thus,  dynamic  piece  patterns  FLOWSIM  accuracy  sawmill  were w r i t t e n and  Six  of  the  two  high  and  mill.  into  cost  In  and  log  FLOWSIM, a  of  employed  logic  for  than  programing  to b u i l d  other  system which  simulators  and  the  FLOWSIM.  model.  effort  and  Using  improved programs  supported  data  the  simulates  Interacting auxiliary one  sawing  GPSS/H,  FLOWSIM,  any  which  developed  existing  language  A  throughput.  newly  SAWSIM, an  simulation  risky.  consideration  breakdown  simulation. into  the  needed  GPSS, was  reduced  major  and  the  accurately  organized  U.S.A. m a r k e t s .  building  l o g breakdown  more  SAWSIM w i t h  of  gain  to  and  version  to  developed  flow  special  was  was  taken  simulator  i t s uneconomical  and  of  A  and  redesigned  log  of  Bloedel  d e c i s i o n s complex  i s a combination  SAWSIM, p r o v i d i n g a  between  the  f a c t o r s were  effective  operation  of  model  MacMillan  modification plan  sawmilling  investment  package.  of  the  because  overseas  of  performance,  model  of  seven  components  major  simulation  sawing  concept  make  Woodroom #3,  necessary  simulation  mill the  most  key  behaviour  two  sawmill  the  transmission  them. market  of p r o d u c t i o n .  r u n s were c a r r i e d Simulation  results  out of  to test  market  l o g demand,  flexibility  lumber  value  i ii  and  volume  equipment  of  utilization  decisions. used  to  the  runs  sensitivity  runs  simulated m i l l  this  thesis  MacMillan  additional per  hour  a flexible  markets.  was  designed  develop  mills  and  other  a  general regions.  model  investment was  modifications.  To  productivity,  an  of  example was  breakdown  made t o e s t i m a t e - the "down" t i m e .  All  shift.  modification plans sawmill  capable  the  analyze  B l o e d e l , t h e model b u i l d i n g  help  final  f l o w p r o b l e m s and  of machine  Although, to  transportation  breakdown on  run  o p e r a t i o n f o r one  p o s s i b l e to b u i l d  and  design  As  of Woodroom #3  overseas  to locate  machinery  in dollars  Simulation  various  of  a n a l y s e s , an  production  machine  mill  accomplished.  lost  is  helped  further  effect  were  and  p r o v i d e d a b a s i s f o r the  Model o u t p u t recommend  estimate three  production,  shows t h a t i t  of p r o d u c i n g  simulation a particular  concepts  for sawmill  for  model  of  sawmill  of  c o u l d be  used  to  simulation in other  Table  of  Contents  Abstract Table  of  ii Contents  iv  List  of  Tables  viii  List  of  Figures  ix  Acknowledgement  xi  1.  INTRODUCTION  1  2.  OBJECTIVES  10  3.  METHODS AND PROCEDURES  12  3.1.  REASONS  FOR COMPUTER SIMULATION  3.2.  WHY EXISTING  12  SIMULATION MODELS SHOULD BE  IMPROVED 3.3.  MAJOR PHASES  3.4. 4.  14 OF THE SIMULATION PROCEDURE AND  THEIR RELATIONSHIP  22  DESIGN  27  OF THE COMPUTER SIMULATION RUNS  LITERATURE REVIEW OF COMPUTER SIMULATION APPLICATIONS  5.  IN SAWMILLING  33  INPUT DATA NEEDED FOR THE MODEL  40  5.1.  ESTABLISHMENT OF THE SAMPLE LOG DATA BASE  5.1.1.  Two-dimensional  diameter  distribution  logs  an a d d i t i o n a l  of  and  40  length  i n Woodroom #3.  shape c h a r a c t e r i s t i c  Taper  as 42  V  5.1.2.  Assignment of  the  of  sample boom l o g s  two-dimensional  to  the  classes  distribution  44  5.1.3.  Bucking p o l i c i e s  of  5.1.4.  Sawlog  for  5.2.  EXPORT MARKETS, LUMBER SIZES AND PRICES  57  5.3.  MACHINERY  60  5.4.  DESCRIPTION  6.  selection  Woodroom #3  47  SAWSIM r u n s  48  OF MILL OPERATION  APPROACH TAKEN IN BUILDING  66  THE MODEL  69  6.1.  THE PROBLEM OF DATA TRANSMISSION  71  6.2.  THE CONCEPTS OF DYNAMIC MODEL CONSTRUCTION  7.  ...81  MODEL VALIDATION  108  7.1.  LOG BREAKDOWN VALIDATION  110  7.2.  PIECE  111  8.  FLOW VALIDATION  COMPUTER SIMULATION RUNS,  RESULTS  AND DISCUSSION  8.1.  STRUCTURE OF INTERACTING PROGRAMS  8.2.  RESULTS  9. 10.  OF SIMULATION RUNS AND DISCUSSION  .127 127  ...132  SUMMARY AND CONCLUSIONS  157  REFERENCES  162  10.1  BIBLIOGRAPHY  OF COMPUTER SIMULATION  APPLICATIONS  IN SAWMILLING  BIBLIOGRAPHY  REFERENCED THROUGHOUT  162  o  10.2  THE THESIS  Appendix  5.1.  1 67  L e n g t h and  diameter  distribution Appendix  5.2.  Boom l o g  Appendix  5.3.  Taper  and  program  of  frequency  boom l o g s  frequency sweep  empirical  distribution  171 172  calculation 173  vi  Appendix  5.4.  Proportion  estimation  of  B and N  boom l o g s  176  Appendix  5.5.  Log d a t a  calculations  Appendix  5.6.  Log p o o l  with  Appendix  5.7.  Examples of  Appendix  5.8.  Bucking  Appendix  5.9.  Expected small  its  177  sample boom l o g  boom l o g  codes  measurements  185  schedules cant  ...184  186  widths  as  a  function  of  diameter  188  Appendix  5.10.Sawlog  selection  Appendix  5.11.Bucking  program  Appendix  5.12.Sawlog  selection  Appendix  6.1.  FLOWSIM l i s t i n g  207  Appendix  6.2.  Headrig  279  Appendix  6.3.  Function  Appendix  6.4.  Transportation and  Appendix  7.1.  lost  table  189 190  program  199  time data  follower  card  writer  equipment  program  speeds  lengths  Validation  284 of  interactive  mill  dynamics  by  GPSS/H run  Base #1  writer  286  Appendix  8.1.  Data  Appendix  8.2.  Log measurement w r i t e r  Appendix  8.3.  DIA w r i t e r  Appendix  8.4.  Matrix  program  Appendix  8.5.  Log  Appendix  8.6.  Condensed  Appendix  8.7.  Production  Appendix  8.8.  Condensed  Appendix  8.9.  Production  Appendix  8 . 1 0 . C o n d e n s e d FLOWSIM o u t p u t - " A "  291  program  program  reader  select  280  300  program  file  writer  305 program  FLOWSIM o u t p u t - " T " results-"T"  market  market  FLOWSIM o u t p u t - " K " results-"K"  296  311 313 322  market  market  324 333  market  335  vi i  Appendix  8.11.Product ion r e s u l t s - " A "  Appendix  8.12.Condensed  Appendix  8.13.Product ion r e s u l t s - " F "  Appendix  8.14.Condensed  Appendix  8.15.Product ion r e s u l t s - " J "  market  FLOWSIM o u t p u t - " F "  344 market  market  FLOWSIM o u t p u t - " J " market market  346 355 357 367  vi i i  List 3.1.  Comparison  5.1.  Lumber  5.2.  Data  o f two l o g breakdown  sizes  green  simulators  17  of v a r i o u s m a r k e t s  to calculate  rough  of T a b l e s  maximum  58  and minimum  sizes  58  5.3.  Lumber  5.4.  Lumber p r i c e s  5.5.  Machine  5.6  Machinery  5.7.  Number o f p i e c e s w h i c h c a n t r a v e l s i d e by s i d e and t h e a v e r a g e t h i c k n e s s o f lumber l a y e r T y p i c a l g r o u p s of GPSS c a r d s and t h e c o r r e s p o n d i n g p a r t s o f FLOWSIM  6.1.  and b y p r o d u c t  specification  $)  (Canadian  59 $)  data  6.3.  Interpretation segments  60 62  breakdown d a t a  Summary o f o b s e r v e d  7.2.  (Canadian  of t h e U.S.A. market  6.2.  7.1.  prices  64  downtime d a t a o f H e a d r i g  9'  65 82 86  of t r a n s a c t i o n s i n d i f f e r e n t  Piece propagation log  89 a t m a c h i n e s used  to process the 115  Movement o f s i d e b o a r d ( T r a n s a c t i o n #4) between H e a d r i g 8' and Combined M a c h i n e #2  120  7.3.  Comparison  122  8.1.  Summary o f market one  shift  of a c t u a l  and FLOWSIM p i e c e s i z e s  runs with  s i m u l a t e d time of  (460 m i n u t e s )  8.2.  Condensed  8.3.  P r o d u c t i o n l o s s e f f e c t o f Combined # 1 breakdown Ranking of the s i x markets  9.1.  results  o f breakdown  147 runs  153 Machine  N o t e : T a b l e s a r e numbered i n a c c o r d a n c e w i t h C h a p t e r numbers. E . g . , T a b l e 3.1 i s t h e f i r s t T a b l e o f C h a p t e r 3.  155 157  ix  List 3.1.  Comparison plots  of F i g u r e s  of two l o g breakdown s i m u l a t o r  18  3.2.  Flowchart  5.1.  Taper v a r i a t i o n  5.2.  Flowchart  5.3.  Sawing  5.4.  Mill  6.1.  Exogenous l o g breakdown transmission  of the s i m u l a t i o n along  of sawlog  procedure  the length  layout  23  of stems  43  s e l e c t i o n procedure  i n s t r u c t i o n s i n the f i n a l  50  boom l o g t a b l e  of the proposed m o d i f i c a t i o n p l a n  6.2.  SAWSIM o u t p u t  6.3.  Network o f p i e c e  6.4.  SAWSIM o u t p u t codes  using  logic  requiring  ..61 70  machine c o d e s  73  routes  using  route  54  data  74 codes  i n s t e a d o f machine 76  6.5.  DIA m a t r i x  6.6.  General  6.7.  Structure  o f D a t a Base #2  6.8.  Algorithm  o f s a w l o g and t h e c o r r e s p o n d i n g  code  by SAWSIM  o f l o g U2/1  DIA m a t r i x  77  structure  80 81 SAWSIM  s e l e c t i o n process  93  6.9.  E x t r a c t o f D a t a Base #1  94  6.10.  Transportation  time  6.11.  Four d i f f e r e n t  ways o f a s s i g n i n g  7.1. 7.2.  SAWSIM o u t p u t t o v a l i d a t e FLOWSIM r e s u l t s P r o c e s s i n g a s i n g l e l o g by FLOWSIM t o compare SAWSIM r e s u l t s  i s a f f e c t e d by p i e c e piece  length  width  98 101 113  with 114  7.3.  C o r r e s p o n d e n c e between t r a n s a c t i o n s a n d p i e c e s  117  7.4.  Time c h a r t  119  o f l o g and p i e c e  processing  X  7.5.  Log  7.6.  P r e d e t e r m i n e d breakdown e v e n t s and t h e e q u i v a l e n t GPSS program segments c a u s i n g t h e s e e v e n t s t o happen  7.7.  used  to check  Deterministic utilization  FLOWSIM run t o check  statistics  interacting  8.2.  C o n d e n s e d FLOWSIM o u t p u t  8.3.  Production results  8.4.  Snap s h o t s o f t r a n s p o r t a t i o n  programs  129 133  of SAWRES  counts at d i f f e r e n t  equipment  simulation  times  8.6.  The t h r e e b u c k i n g p o l i c i e s r e s u l t i n d i f f e r e n t sawlog l e n g t h d i s t r i b u t i o n s GPSS segment o f m a c h i n e r y breakdown s e n s i t i v i t y run Computer usage s t a t i s t i c s of a t y p i c a l FLOWSIM run Note:  4x4  clock  Use  9.1.  t o produce  '..142  8.5.  8.7.  124  ...125  Structure  of Twin Saw  ...123  machine  statistics  8.1.  piece  of  machine u t i l i z a t i o n  ...148  lumber  F i g u r e s a r e numbered i n a c c o r d a n c e w i t h C h a p t e r numbers. E.g., F i g u r e 9.1 i s the f i r s t F i g u r e of C h a p t e r 9.  150  151 154 1 60  xi  ACKNOWLEDGEMENT  I  wish  University providing of  to of  acknowledge British  and  extended computer This  study  A  special  MacMillan Log  of  Bloedel  was  skills.  MacMillan  Centre  support for  of  the  Bloedel  Ltd.,  of  the  Faculty  the s u b s t a n t i a l l y  sawing  thanks  Ltd.,  for  t i m e and to  their  provided  simulation  by  Jan  the  package  Chris  co-operation  advice.  Boniface  and  of  (SAWSIM)  gave much u s e f u l  Aune and  help  at  guidance.  FORINTEK Canada C o r p . ,  Western  invaluable.  Paszner, Wong, and  support  have been p o s s i b l e w i t h o u t  shared h i s valuable note  and  resource  Computer  made h i s  Appreciation Laszlo  the  financial  usage.  measurement d a t a  Laboratory  Barry  the  would not  Howard L e a c h who available,  Columbia  f e l l o w s h i p s , and  Forestry  the  i s a l s o due  to  John  Emanuel,  Antal  Har.ry S m i t h , W i l l e m V a e s s e n , D o u g l a s Glendon  Young who  contributed  their  Kozak,  Williams,  professional  1  J_j_  The  lumber  British  The  number  d u r i n g the  labour  force  was  the p r i m a r y  i n the  whole p r o v i n c i a l The  varied  in  comparison  During  the  The  problem  70  last  two  on  highly  and  this  source  all  lumber  Columbia  products  industry. in  role  largest  Sawmills  i n d u s t r y has  exported  export decades  exposed  changing  The  1982.  sawmills  employed  was  70%  of  This industry  British  a great  in  lumber  in  Columbia  impact  severe  this  age  on  the  i s improving  Geographically,  share  southern  has  also  in  was  53-73%  high.  (77).  This lumber  pressures.  U.S.A. lumber  i n the h o u s i n g  pine  years  been  l e a v e s the p r o v i n c i a l  southern  and  15  of t h e U.S.A. m a r k e t ,  difficulties.  from  the q u a l i t y  share  to d i f f e r e n t  demand  selling  d u r i n g the past  markets,  with v a r i a t i o n s  as more p l a n t a t i o n - g r o w n increasing  the  decade.  80%.  the c o m p e t i t i o n  With  of  in B r i t i s h  t h e U.S.A. market  cyclically  is  63%  employment  lumber  to other  been c a u s i n g  of  lumber  substantially  correlates has  between  reliance  producers  forest  is  economic  economy.  p r o p o r t i o n of  has  last  generator  T h e r e f o r e , the  important  province  of e m p l o y e e s w o r k i n g  the  heavy  The  i n Canada, p r o d u c i n g  65,000-70,000  (77).  i n d u s t r y p l a y s an  Columbia.  manufacturer  INTRODUCTION  i n d u s t r y , and  Compounding  yellow pine  reaches  selection  markets,  cutting of  the  producers age  (86).  lumber  from  (86).  British  Columbia  includes  Coastal  and  2  Interior coast  lumber  mills  producing  dominated  considerable  lumber  competition  their  lower  regions.  has  to  than  i s possible in antiquated  caused  a  western  lumber  mills  are  producing  facing  diversification A quote Bitish on  strain  from  Economic  strategies  Prospects  interior  t h e West  for  in  the  Canada, producers  productivity  Coast.  Canadian and  lumber g r o w t h of  has the  recent  years.  Coastal  tough d e c i s i o n s with  respect  t o market  advancement  report  Western  i n the p r o f i t a b i l i t y  the COFI  Columbia)  from  much h i g h e r  on  potential  sawmills  some  and  mills  traditionally  from  l o g g i n g c o s t s and  in export  severe  exports  developed  due  T h i s change  While  in sawmill  (Council (54)  in  submitted  1983,  t o make the c o a s t  of  mills  technology. Forest  t o the  summarizes  Industries Royal  the  profitable  of  Commission  best  future  again:  "1. Maximize recovery of, and demand for, higher value upper grades and pursue those markets and end uses t h a t o f f e r the best l o n g t e r m volume p o t e n t i a l . 2. D e v e l o p and m a r k e t a new line of higher value s p e c i a l t y products. 3. Concentrate more on o v e r s e a s m a r k e t s where t h e y c a n compete b e s t (e.g. Japan and North A f r i c a ) with t h e i r c o n s t r u c t i o n grades. 4. Take appropriate action to enhance the v a l u e of lumber p r o d u c t s by making them more s u i t e d f o r the market and i n t e n d e d u s e . " Indeed, a c c o r d i n g key  revitalization  a p p e a r s t o be grades. overseas  in  to the  of t h e  S a l e s have t o t a k e  U.S.A. m a r k e t s w i t h Changed  of  of  the  position  "selected  i n t o account  industry,  the  the  of c o a s t a l m i l l s  structural"  c o n t i n u i n g t o compete  lower  marketing  trends  competitive  production  markets, while  recent  needs of in  lumber  different  domestic  and  grades. strategies  will  require  a  complete  3  modernization lumber of  of  sizes  flexibility  mills  renovation computer  required  to  be  the  production demands. British products flow  of  conceived  and  Ltd.),  static  specifically During  sawmill  was  of  profitability  could  The  While be  and  sawmills  was  be  redesign  with  with  varying  Woodroom  be  cutting  evaluated  #3  a plan  Overseas  through  a  and  Company  thesis. Woodroom  f o r m o d i f i c a t i o n was  #3  existing submitted  of o p e r a t i n g e f f i c i e n c y  a n s w e r e d by was  hybrid  developed  f o r r e - d e s i g n i n g the  questions  e v a l u a t i n g the  market  patterns, piece  Leach  this  of  a t Harmac,  FLOWSIM, a dynamic m o d e l , as p a r t of  in  the concept  multipass-headrig m i l l .  need  simulation technique  predicting  will  a change-over  1975-83, t h e o p e r a t i o n of  r e c o g n i z e d and  t h e management.  appropriately  these c o n s i d e r a t i o n s  ( p r o p e r t y of H.A.  m o d e l , and  uneconomical.  design.  will  SAWSIM  years  commitment,  complex  analyzes  corresponding  f o r Woodroom #3 the  with  accordance  selected  sizes,  became  computer  in  production model of  study  Ltd.'s  a large-log  simulation a  The  Bloedel  special  old  in m i l l  specialists,  the  degree in  investments  tool,  sawmill  a  available  financial  o b j e c t i v e design  was  sawmill  Columbia,  any  in  specialized  mills.  flexibility The  Before  alternatives  thesis  MacMillan  not  Large  of  often  strategies,  time.  experience  evaluate  present  of  The  automation  inevitable.  o p p o r t u n i t i e s i n mind.  one  mills.  the p r e s e n t  of o l d c o a s t a l  The  by  and  s i m u l a t i o n as an with  and  at  will  combined  process  coastal  require well defined cutting  production  coastal  the  trial  and  error  and  i n time,  deemed t o be more e f f i c i e n t  behaviour  of  the proposed  new  a in  mill  4  Originally, dimension for  Woodroom  lumber  for  the uneconomical  • The c o s t Interior  the U n i t e d  operation  constructed S t a t e s market.  of the m i l l  to  produce  Major  reasons  were as f o l l o w s :  i s twice  that  of  logs.  dimension  from  an  increasing  number  of  Interior  reduced  housing  producers.  • Decreasing  markets  i n t h e U.S.A  the c o a s t :  hence h i g h  high  cost  because  during  • Disadvantageous on  was  o f e x t r a c t i n g l o g s on t h e C o a s t  • Competition  starts  #3  of  the l a s t  five  geographical  e l e v a t i o n , steep  greatly years.  circumstances slopes  of h a r v e s t i n g  on m o u n t a i n s i d e s  and  of r o a d c o n s t r u c t i o n .  • Expensive  sawmill  manpower  - consequently  high  conversion  cost. The  basic  i d e a o f t h e m o d i f i c a t i o n was t o  yielding  higher  countries  appeared  small the  cutting  extremely  producer  selling  markets  States  is difficult  v a r i a b l e nature  market's c u r r e n c y  Lumber m a r k e t s  t o be a t t r a c t i v e .  countries;  competition  prices.  the  The  relative  demand  to p r e d i c t .  of economic  t o the currency  create  Therefore,  for This  power of a producer;  from c o u n t r i e s s u c h a s Sweden, R u s s i a  (50).  f o r overseas various  i s due t o  s t r e n g t h of buyer  buying  of the  products  t h e key c o n c e p t  and  particular and  supply  and t h e U n i t e d  in designing  t h e new  5  mill  i s market  bearing  in  flexibility,  mind  that  are h i g h l y v o l a t i l e Thus t h e m i l l  i s planned  of i t s production  with  the balance  production.  dimension  1 9/16" 1 13/16"  lumber,  of producing  up  export  as  extreme  the  other  small c u t t i n g  to  product of  markets  with  lumber  sizes  thicknesses are:  States  dimension,  Japan,  North France  4 1/8"X4  1/8"  close  technology,  conversion  markets  of  2  A  designed  a s one extreme  U n i t e d Kingdom and A u s t r a l i a ,  1/2"  being  of small c u t t i n g s f o r export,  1 7/8"  3"  and  lumber  United  t o be c a p a b l e  lumber  The most v i a b l e  the c o r r e s p o n d i n g  is  o p p o r t u n i t i e s i n overseas  i n t h e form  as dimension  100%  and  selling  mill  and v a r i a b l e .  70%  mix,  i . e . , the  Africa  and Belgium,  and the U n i t e d Japan  (later  referred  interrelationship as w e l l as  process,  Kingdom,  the  between search  t o a s 4x4) t h e above for a  less  expensive  n e c e s s i t a t e m o d i f i c a t i o n of the c u r r e n t  mill  operat ion. Conversion logs, It to  facilities  up t o a n d i n c l u d i n g  is  planned  mill  t h a t a l l of the m i l l  A detailed  are presented Accordingly,  evaluated  with  f o r the primary  the headrigs, w i l l  t h e back e n d o f t h e m i l l ,  machinery.  used  the  remain from  the  same.  the headrigs  be removed and r e p l a c e d by new  description  in a later  special  will  machinery  breakdown o f  and l a y o u t  of  the  modified  section.  proposed  attention  mill  operation  to the redesigned  had part  to  be  of t h e  6  conversion and  process.  technology  sawmill  had  patterns lumber. raw  required  for  turns  material  is  also  centres,  and  belts  roll  the  variety  system  and  the  major  to  with  the  performance  of  i t s response  production  out  t o be  an  of  final the  product sawmill  reasons  complicated.  f o r the  total  simulation  consider  way  consequence estimates  of  i s t o be logic  i t simulates  as  dynamic  l o g breakdown  logic  log of  result  as this but  a  simulated and  piece  existing  the  mill  a  design, were  technique  the for  i t s performance.  must have a l o g breakdown  their  perceived  investment,  l o g breakdown.  that  The  proposed  the  of  conveyors,  very  and  drawback  machine  the  l o g throughput  sense t h a t  shape.  f o r v a r i o u s m a r k e t s , make  efficiency  the  The  sizes  production  of a m i l l  log  of c r o s s c h a i n  the  operation  task.  interacting  general,  the  dimensional  complex  of  revised  by  computer  e v a l u a t i o n of  and  cutting patterns,  ($ 28 m i l l i o n ) of  t o use  the  dictated  of modern s a w m i l l i n g cost  machinery  randomly c h a n g i n g  breakdowns  Different  new  to v a r i o u s c u t t i n g  export  extremely  c h a r a c t e r i z e d by  cases.  high  In  as  stochastic  of  preliminary  l o g mix,  t r a n s p o r t a t i o n equipment  of  complexity  the  constraints,  analyzed  There are  on  as  t o be  This  and  Given  is largely  only  a l s o that  piece  dynamic.  sawmill  The  inaccurate flow  if  model  Dynamic time.  in A  simulation i s  simplified,  cone.  that  Therefore,  a f u n c t i o n of  m o d e l s of  truncated  i s not  as  depends  a c c u r a t e l y , the  must be  flow  in a sawmill  i . e . , they  disadvantageous lumber  recovery  simulation  becomes  inaccurate. To in  this  ensure accurate  s i m u l a t i o n , the  t h e s i s p r o j e c t has  access  dynamic model  developed  to a h i g h l y s o p h i s t i c a t e d  log  7  breakdown  model.  behaviour  more  Thereby, mill  the  and  was  SAWSIM  text  to analyze  and  s e r v e s as  examination  J.O.  analyst 2.  general,  for  Henriksen  of  is  is  one  logic  of  of t h e computer  simulation  GPSS/H  the  GPSS  Wolverine be  of  (25).  sawn.  referred  In  the  It w i l l other  t h e dynamic  of  model  this  is  most be  used  words,  it  model.  simulation literature  a s i m u l a t i o n model  showed  technique:  time  requires  i n mind  and  its  t h e above two  demanding  a  large  application  disadvantages  in sawmill  particular,  one  of  the purposes  of  potentials  of  a  new  design  The  application  the  usage of SAWSIM,  the  the  for  the  amount  of  time.  Bearing  logic,  by  Purpose  and  running  computer  a  the  ( p i e c e FLOW S I M u l a t i o n ) .  commonly m e n t i o n e d d i s a d v a n t a g e s building  before.  (General  T h i s dynamic model w i l l  log  l o g breakdown  mill  coordinate  compiler  s i m u l a t i o n packages the  did  and  processed  SIMulation)  sawing  the  by  as FLOWSIM  (SAWmill  i n f o r m FLOWSIM how  1.  models  i s c o n s t r u c t e d i n GPSS  (62)).  the a c t u a l  flexibility.  developed  the  comprehensive  two  used  language  Corporation  to throughout  An  be  other  (GPSS/H i s t h e most e f f e c t i v e  language Software  i s to simulate  than  for production  System)  compiler.  to  can  dynamic model  Simulation  intention  accurately model  operation The  The  were  powers  design  thesis and  as  its  already  i s to r e v e a l  evaluation  existing  to l e s s e n programing  sawmill  simulation.  If  effort  in  evaluation in  log and  sawmill  the  technique.  of GPSS/H i n c o n s t r u c t i n g t h e dynamic model,  thought of  sawmill  this  of m o d e l l i n g  and  breakdown to  improve  modelling  8  principles steps  of  model the  brought  a closer  building  purpose The  of  evaluate thesis  of  Chapter  the  Chapter was  employed to  model  Chapter computer  t h e model  5 surveys  and f i n a l or b u i l t  interactions  application  and  the  of  be  used  writing Based  described  literature  products.  to  this  on  this  and p r o v i d e s  the  research.  D e s i g n of  of  why c o m p u t e r s i m u l a t i o n  experiments in this  data  t h e computer  chapter.  r e v i e w of in  for  model  the  two major  groups  sawmi11ing. groups  These data  of  are  logs,  machinery,  either  inputs  of  i n t o the m o d e l .  describes  6  to of  the  #3,  t h e p r o b l e m and why t h e p a r t i c u l a r  t h e major  new  analysis,  Woodroom  into particulars  simulation applications  Chapter  model,  a  the  fulfilled.  and t h e p u r p o s e s  this  starting  and i f  technique  with questions  also  4 gives  Chapter technology  of  applied. is  would be  the  as  in sawmill  redesigning  2 enters  attack  simulation  serve  i n the p r e v i o u s p a r a g r a p h s .  deals  3  is  the  thesis  of  objectives  structure  of  this  analysis,  were d i s c u s s e d  thesis  would be a c c e p t e d  aspects the  this  sawmill designs,  the m o d i f i c a t i o n p l a n ,  introduction details  writing  of  in  e v a l u a t i o n of concepts  major  limitations  together  among  SAWSIM as  t h e major various the  i m p l e m e n t a t i o n of  log data  concepts  parts  of  of  model  the  building,  model,  breakdown l o g i c  of  the  the dynamic  transmission  between  accuracy  which  SAWSIM  t h e dynamic m o d e l . Validation,  simulates  mill  Chapters conclusions.  the  degree  operation, 8  and  9  is  of  to  the  model  o u t l i n e d i n C h a p t e r 7.  discuss  details  of  the  results  and  9  Chapter thesis.  10  Computer  lists  the l i t e r a t u r e  simulation  literature  referenced i s grouped  throughout  the  separately.  10  2_;_  In mill  the  previous  operation  modification and cost  of  Hence  are  #3  which were  in balance,  recommended  desire  investment  some r e a s o n s  Woodroom  plans  the  the  chapter  of  expenditures  OBJECTIVES  of  also  management  like  the  mill  discussed.  to  i s high:  the  the  financial  answers  to  The revenue  The $ 28  decrease  Before  management would  non-profitable  established.  t o put  reconstruction  i s understandable.  made, the  were  intended  were  f o r the  total million.  risk  of  commitments  the  following  questions: •  How  will  the  redesigned  mill  react  to d i f f e r e n t c u t t i n g  strategies? • Will  the  piece  • Will  the  machine u t i l i z a t i o n  further  improved?  • How  flow  provide  What a r e  sensitive  is  the  the  the be  required  throughput?  s a t i s f a c t o r y and  recommended mill  log  to  can  i t be  modifications? anticipated  machine  reliabi1ity? According are  the 1.  To  examine how  above q u e s t i o n s  the  mill  will  More s p e c i f i c a l l y ,  produces  for  U.S.A. d i m e n s i o n , two  the  the  research  objectives  following:  programs. mill  to  Japanese  one  of  to evaluate  the  North A f r i c a ,  markets,  4x4  react  and  six  to  lumber  Kingdom, F r a n c e ,  lumber  cutting  p r o d u c t i v i t y when  possible  United  different  for  the  markets: and  the  remanufacturing  purposes. value  The e v a l u a t i o n o f p r o d u c t i o n  of  lumber  material  requirements,  transportation  equipment  2 . To e v a l u a t e machines  will  equipment  is fully  design  and  and  to  occupied  estimates  the  raw  machine  and  counts.  and  wait  recoveries,  determines  piece  how l o n g  have  capable  machine  production  p r e d i c t s t h e volume and  with  what  frequency  various  b e c a u s e downstream t r a n s p o r t a t i o n  and  to  of e l i m i n a t i n g these  recommend blocked  changes  i n the  s t a t e s and  improving  utilization.  3 . To  analyze  the s e n s i t i v i t y  of the flow  plan  t o machinery  breakdowns. 4. To b u i l d carry  out  a s i m u l a t i o n model  experiments  in  which  enables  conjunction  with  i t s " user the  to  foregoing  quest i o n s . 5. To w r i t e a u x i l i a r y • supporting  programs the data  transmission  SAWSIM and FLOWSIM t h e dynamic • to select to a given  sample  sawlogs bucked  bucking  policy  between  model, according  f r o m t h e company  boom l o g d i s t r i b u t i o n . 6. To recommend methods o f computer applicable model  i n sawmill  building  design  approach taken  s i m u l a t i o n found  to  be  and a n a l y s i s i n t h e view of t h e new in this  research.  12  3_;_  In  this  simulation  METHODS AND  chapter,  is  reasons  employed  and  simulation  general,  evaluating  computer  models  should  model c o m b i n a t i o n  procedure  there  are  three  or p r e d i c t i n g the o p e r a t i o n  • performing  and  the  be  i s used. design  of  approaches  to  discussed.  • building  possible of v a r i o u s  e x p e r i m e n t s on t h e a c t u a l  formulating  representative  and  solving  of the r e a l and  an  systems:  system,  analytical  model  as  system,  experimenting  on a s i m u l a t i o n model o f t h e  system. Concentrating  only  on s a w m i l l  systems,  sawmill  c o n s t r u c t i o n and o p e r a t i o n  Besides,  s t o c h a s t i c l o g shape c h a r a c t e r i s t i c s  to  why  REASONS FOR COMPUTER SIMULATION  In  real  simulation  s i m u l a t i o n experiments a r e a l s o  3.1.  •  dynamic  discussed  the m o d i f i c a t i o n r e d e s i g n of  why t h e SAWSIM-FLOWSIM  Major phases of the computer  are  to analyze  Woodroom #3, why e x i s t i n g improved  PROCEDURES  repeat  e x p e r i m e n t s under  of d i f f e r e n t influencing  excludes  the  the f i r s t  Analytical  make  t h e same c i r c u m s t a n c e s  ways o f sawing w h i c h a r e t h e most lumber  high  cost  of  approach.  i t impossible on t h e e f f e c t  sensitive  factors  yield.  m o d e l s a r e b a s e d on t h e u n d e r l y i n g  structure  of  13  the  system  systematic  in  the  methods t o s o l v e  demand t o b u i l d the  other  markets,  if  mathematical log  selection machinery  of computer  Computer techniques  mix,  breakdowns  preconceived words,  a  models  system  is  i n the is  in  explains  low  approach  modeling  time-  superior  is  demand  possible. of  various  random components of  make  sawmill  Hence, t h i s  to  log  systems  study  too  r e s o r t s to  techniques. one  complex  of  form of  The sawmill  the  most  systems.  programmed  elements.  growing  (35)  Reynolds  explore  computer  constantly  simulation  Available  relatively  product  of m a c h i n e r y ,  simulation  to  the  equations.  them, make t h i s  to approach a n a l y t i c a l l y .  use  among  them, and  analyze  changing  wide  g e o m e t r y and  the  and  two,  Unfortunately,  complex  form of m a t h e m a t i c a l  The  computer  widely  used  approach  uses  programs.  to simulate  popularity  of  applications.  In  other  the i n t e r a c t i o n s simulation  is  A quotation  from  why:  "By u s i n g a computer t o s i m u l a t e t h e s a w i n g , we have devised a way t o saw the same l o g i n many d i f f e r e n t ways t o f i n d out w h i c h way gets the best yield from the log. Sawmill production managers o f t e n f i n d i t h a r d t o t e l l what sawing p a t t e r n w i l l y i e l d t h e most. I f sample l o g s a r e sawed in one sawing p a t t e r n , t h e y can not be reassembled and sawed again in a different pattern. And i f a new sample of l o g s i s used f o r e a c h new sawing p a t t e r n , i t i s h a r d t o tell if differences in y i e l d a r e due t o t h e sawing patterns or are due to natural differences between t h e l o g s i n t h e s a m p l e s . But by u s i n g a computer to simulate t h e s a w i n g , t h e same l o g sample can be sawed a g a i n and a g a i n , and yields of the different sawing patterns can be compared." Notice rationale log  that  the  above  f o r computer  breakdown  aspects  quotation  from  Reynolds  simulation a p p l i c a t i o n regarding of  sawmilling.  E v a l u a t i o n of  gives only  a the  sawmill  1 4  behaviour  requires further  simulation  techniques  transportation piece  flow  transportation frequencies,  simulation  models  of  sawmill  3.2. Log affecting model the  facts,  of  accuracy. analysis  this  models  How  this  first  machine  behaviour,  factor  machine and  bottlenecks  speeds o f machine breakdown  of  and/or  times  and  this  study  employs  the  Employment  of  analysis.  computer  The method o f  and  is  believed  new model p r o v i d e s  to  from  improve  improved  ways  section.  throughput, must  be  as dealt  two  major  with  i n any s a w m i l l  operation.  The  factors  effect  i s s t r a i g h t f o r w a r d ; t h e h i g h e r t h e lumber  the higher  the revenue.  organized m i l l -  utilization  breakdowns.  significantly  of  EXISTING DYNAMIC MODELS SHOULD BE IMPROVED  mill  machine time  possible  i s d e s c r i b e d i n t h e next  breakdown and l o g  a not w e l l  like  s t u d y makes i t d i f f e r e n t  i f one wants t o s i m u l a t e m i l l  recovery, of  model  application  areas.  simulation.  existing  WHY  surge  i s n o t new i n s a w m i l l  the  already  dynamics  machinery  above  computer  constructing  mill  inappropriate  the  of  - and hence  interactions,  and i n a d e q u a t e  technique  simulation  by  on  equipment,  Considering  other  -  equipment  caused  analysis  affect  caused  The s e c o n d  factor-in  exercises i t s effect by c o n g e s t i o n  Conversely,  profitability  of the  value  the case  through  poor  in bottlenecks  high  throughput  mill  through  of  or can  higher  productivity. The  desire  t o improve m i l l  performance  t h e above two f a c t o r s h a s been t h e  subject  by o p t i m i z a t i o n o f of  sawmill  system  1 5  analysis  for  a  long  number of computer Chapter  10.1).  attention  has  been than  greater  the  than  breakdown  relative  of  The  had  carry  small;  computer  statistical makes  additional  the  their  A  issue  are  accurately,  flow sawn.  over  research  scope  knowledge special  On  of  need  introduced  into  One  and  techniques  stochastic  might and  systems  of dynamic they  and  language,  techniques  of t h e s e  and  dynamic  systems e a s i e r ,  applications  improvement.  which  i s needed  hand,  simulation  simulation  later  about the  technology  of s i m u l a t i o n  of s t o c h a s t i c  log  the undertaking i s  the o t h e r  purpose  log  Models of  lumber  of  on  on dynamic  calculations  p i e c e s of  Consequently,  were  performance i s  research  f o r a n a l y s e s of d i s c r e t e ,  l o g breakdown  Piece  Thus  of g e o m e t r y , s a w m i l l  Development  new.  and  on m i l l  geometrical  the  analysis  suitable  sawmilling  logs  knowledge  be r e q u i r e d .  weaknesses of  much more  T h e r e a r e two  A l a r g e amount of c a l c u l a t i o n  although  methods.  relatively  in  (see  recovery  i s the f o l l o w i n g .  language are s u f f i c i e n t .  require  languages  priority  of r e c t a n g u l a r  purpose  relatively  is  however,  (6,36,65).  dynamics.  out r e p e a t e d  positions  this  also  large  sawmilling  lumber  dynamics  second reason  l o g s can be s u b d i v i d e d .  which  the  o f l o g breakdown  mill  simulation  breakdown  models  in  applications,  to  to m i l l  effect  that  simulation.  a  applications  these  paid  can be s e e n from t h e  for this.  First,  for  This  simulation Among  (17,25,41,42,43) reasons  time.  models  still  have  i s the a c c u r a c y  logic.  in a mill  depends  Therefore,  to a large  i f we  d e g r e e on  the  way  want t o s i m u l a t e p i e c e  flow  dynamic models must have a s a c c u r a t e  log  breakdown  16  logic  as  sawmill  possible.  simulation  simplified; other  words,  diameter, not  they  only  but  also  mill  is  consider  uniform  only  that  taper  the  and  mill.  in A  To  following  log  breakdown  small  a truncated  length.  lumber  error  The  of  the  is  In  considered  are  calculation dynamic  fairly  cone(6,36).  c o n s e q u e n c e of  recovery  cone,  log  i n the  is  this  is  obtained  behaviour  of  is  utmost  l o g breakdown the  dynamic  importance  twist.  of  Table  less  of logic  can  behaviour  this,  pieces  i t takes  shape  that 3.1  The  second  the  lead of  consider  a the  the  3.1  compare over  Thus,  or  log  in  also  i t could  sawn by two  into  the  two  cases.  underestimates  the  Considering  an  logic,  could  through not  butt  ovality  2 m i n u t e s , a dynamic  flowing  a  addition  length,  the  log  as  t o p and  takes  sawlogs.  breakdown  number of p i e c e s shift.  only  same l o g was  1 boom l o g p e r log  the  the  sawlogs.  different  simulator,  along  for a l l three  accurate  per  Figure  three  two  characteristics,  pieces of  by  i n t o account  exactly.the and  into  considers  simulator  average throughput  underestimate  one  accurate  lumber  less  first  cut  "sawn"  sweep, v a r i a b l e t a p e r  Notice  simulators.  The  cross are  log length.  three  consideration  is  then  i.e.,  and  these  number of  hemlock sawlogs  diameter  The  simulation  regarding the  simulators.  truncated  960  logic  of  example.  three  having  l o g as  breakdown  illustrate  A western  and  l o g breakdown  simulation  to erroneous c o n c l u s i o n s  to  the  dynamic models  inaccurate.  importance.  end  their  existing  l o g shape c h a r a c t e r i s t i c s  inaccurate  Accuracy  These  drawback of  i s that  the  that  A  the  represent  model,  over  or  mill  by  the  real  Table  3.1.  Comparison  of  two  l o g breakdown  simulators  Boom l o g B228 S a w B228/1  l B228/2  o g B228/3  Case#1 (Simplified l o g shape)  32  20  14  Case#2 (Accurate shape characteristics)  33  18  13  mill  dynamics. In a d d i t i o n , the  the  whole"story  difference B228/1. piece log  is  flow  from  headrig  would a l s o be  number  of  the  two  b a s e d on  pieces Fourth,  cases. these  comparisons  (33  simulator.  S e c o n d , the  24).  one  of  produced n o t i c e how  be  by  from t h e the  Transportation  can  in  the  pieces  overestimated  erroneous  in the  sizes,  detail the  center  sideboards  from  s i z e s of  7).  cant  false accurate  overestimated  1 (8 v s .  equipment  less  the  sawlog  how  of  flowing  tell  instance, c a s e of  number  e d g e r would be  number  does not  For  made b a s e d on  First,  to  32)  analysing be  pieces  simulation.  vs.  i t i s worth  trimmer  vs.  dynamic  p r e d i c t i o n s might  breakdown  4).  faulty  only  However,  flowing vs.  of  d i f f e r e n c e i n lumber  1  (5  edger  to  Third,  the  differ  some p i e c e s  by  by  2  differ  (26 in  occupancy c a l c u l a t i o n s ,  would a l s o  made i n c o n j u n c t i o n  be with  false. sawlog  Similar B228/2  and  employed  in  B228/3. These a r e this than  the  research others  have  r e a s o n s why  tries done.  to  use  the  dynamic  more a c c u r a t e  However,  to  build  model  l o g breakdown an  accurate  logic log  18  •  SAtrsiti 'LOT •221/ 1 U H M •  |  2104  12  2 X 0 . 12  2 l 0  • *•  2I0C 12 1 2  *  • •  II —  12  1.  ll II « .  12  1 |  12  3 «Ot  12  2X0.  12  2X0.  12  2>0C  12  210*  12  || 2 . 0 ,  12  2X0*  12  II  2»0»  12  2>0«  12  II""  12  2X0*  12  II  2*0*  12  12  2X0*  12  || 2 , 0 .  12  ||  II  2 . 0 .12  2 x 1 0 2  CASE #1 - Number o f lumber p i e c e s  SA»SIX PLOT B228/ 1 UH3«  2X0.  12  210.  12  2 X 0 . 12  2X0.  12  210.  12  210.  12  210.  12  2X0.  12  210. 12  210.  12  2<0« 1 2  2X0.  12  210.  2<0*  12  •  • 2X04 12 '  I  1 2  —« •  Figure 3 . 1 .  1  2 X 0 .  12  12  2»0*  12  | 2 X 0 . 12  2X0*  12  I 2 X 0 . 12  12  1  2X0. •  i s 32  1  1  2 X 1 O O ' 4» •  •I  •  2 X 0 1. 2  2X04  -0  1  C A S E #2 - N u m b e r o f l u m b e r p i e c e s i s 3 3 Comparison o f two l o g breakdown s i m u l a t o r plots  b y SAWSIM  19  •221/  2  •  UM34  •2X0*  2 I 0  3 2  •1X10  11  2X10  22  2110  22  > H 0  22  2110  22  2>10  22  2X10  22  2X10  22  2X10  22  2X10  22  |  CASE #1  |  •  1  | |  .'I  1 1 1  | 1  2 I 0  c  2 2  2 X  i  0  0  1  2X01 22  - Number  o f lumber p i e c e s  i s 20  S U S t d PLOT • 2 2 * / 2 UM34  |-2X0»  2X0*  22  2X10 22 2-  2X10 22  2X10 22  J.-2  1 1  2X10 22  2X10 22  2X10 22  2X10 22  '2 X  2X10 22  -|  3.1.  2 O  2|»-  o-o|  Figure  2 I 0  2 I 0 ( 22  C A S E #2 - N u m b e r o f l u m b e r p i e c e s i s 18 Comparison of two l o g breakdown s i m u l a t o r plots - con'd  by  SAWSIM  20 S'VSIB  PLOT  • 2 2 * /  2  UM32 2X0*  2>12  II  2112  11  2X12  II  2X12  11  10  •  •  I1 1 2  | | |  B1 2  0  •  CASE #1  S.VSIP 0221/  I  I  2X10 II  - Number  o f lumber p i e c e s  i s 14  PLOT 1  UM33  l " 2  *  1 2  •  Figure  3.1.  I  2IOI  12  •  • 1  C A S E #2 - N u m b e r o f l u m b e r p i e c e s i s 13 C o m p a r i s o n o f two l o g breakdown s i m u l a t o r plots - con'd  b y SAWSIM  21  breakdown  simulator  expensive. dynamic  To overcome model  sophisticated and  the  piece  flow  and  development. capabilities analyst  c a n communicate w i t h  of  time  can  superior  run-time  economics  point  with  of  activities.  these  efforts  activity  i t s general-purpose specialized  the o u t s i d e world  "Models t y p i c a l l y  6:1  Vaessen  GPSSV.  overall  (79).  easily,  construction of  effort-lessening  a  GPSS/H  of  were  my  Some  superior  decrease  simulation  recognized.  amount  etc. Its  the  compile  the  e . g . , he  great  improvements  These  model  reports;  from  with  of  input-output  i s significant  than  a  i s the  of  performance view.  As  process  facility,  of  a  new v e r s i o n o f t h e GPSS f a m i l y  o f GPSS/H c a n s u b s t a n t i a l l y  advantages  running  i t s debugging  achieved  applications",  the  and  by  GPSS/H  consistently  features  saved  SAWSIM  in detail.  t o r o u t i n e s w r i t t e n i n FORTRAN; be  most  the c o s t e f f e c t i v e n e s s of  labour-intensive  instance,  today.  consuming  improve  h e l p the a n a l y s t produce  gain access  During  the  the  a g r e a t amount o f e f f o r t has  time  This  of  the  a s an e x o g e n o u s s o u r c e o f  demanding  the  itself.  For  can  faster  time  reduce  decrease  one  building  One o f t h e r e s u l t s  compiler to  both  consequently  model b u i l d i n g .  is  activity  in existence  of these d i s a d v a n t a g e s ,  programming  GPSS/H  which  be d i s c u s s e d l a t e r  are  to  programing  i t s application  earlier,  model  expended  helps  of  demanding and c o n s e q u e n t l y  tiring  l o g breakdown m o d e l s  mentioned  recognition  time  SAWSIM,  simulation w i l l  simulation  been  very this  uses  problem  As  is  computer 2.5  times  users  have  with  their  compilation  simulation costs. model  The  f e a t u r e s o f GPSS/H were a d a p t e d  the  above  t i m e - s a v i n g and to evaluate the  22  redesign The  of Woodroom  #3.  usage o f SAWSIM, a s an a l r e a d y  simulation  package  was a l s o t h o u g h t  f o r l o g breakdown  The  foregoing  simulation and  would  particular  be  used  in  discuss  the  major  will  procedure  and t h e i r r e l a t i o n s h i p .  chapter  activities  Notice  gives  t o be done  relationships that  of  different  various  the m i l l .  model c o m p o s i t i o n this  research.  phases  of  computer  of  SAWSIM  The f o l l o w i n g the  contains  the  problem  vertical  i s solved  sidelines  or  simulation  problem  simulation  are either inputs  final  results  simulation  down t o t h e r i g h t ) .  While  there  t o keep i n m i n d .  a r e two t h i n g s  reading  3.2.  This provides  meaning  of a b l o c k  with  oblique  of t h e s i m u l a t i o n  explains  briefly  lines  simulation (shaded w i t h following  First,  lines  how with  sloped  phases  (not sloped  paragraphs,  underlined  blocks  assistance  3.2.  i n the  (shaded w i t h  the  The  by F i g u r e  Blocks  s e c t i o n always r e f e r s t o p a r t i c u l a r Figure  major  procedure.  of  results  the  procedure.  assignment  i n the s i m u l a t i o n  internal  of  phases a r e d e p i c t e d  t o , whereas t h e l o w e r p a r t  down t o t h e l e f t ) , shaded),  the  outline  The upper p a r t  sidelines  i t belongs  general  s h a p e s have d i f f e r e n t  3.2.  in  and t o improve t h e  block  of F i g u r e  phase  a  during  flowchart  this  effort  model,  MAJOR PHASES OF THE SIMULATION PROCEDURE This  the  of t h e dynamic  in evaluating  sections  3.3.  sophisticated  d i s c u s s i o n gave a r a t i o n a l e o f why  and why t h i s  FLOWSIM  logic  t o l e s s e n programming  powers o f t h e a p p r o a c h t a k e n  existing  text in  of the flowchart  t o keep t r a c k o f what  23  (SO T  .  CROSSCUT BOOM LOGS INTO SAWLOGS ACCOROING TO/ BUCKING POLICY CALCULATE SAWLOG MEASUREMENTS  (5. 1 >  ~ ^ r ~ —  | SAWLOGS| (5.1)  7  ECT SAMPLE SAWLOGS  GROUP SAWLOGS OF SIMILAR SHAPE AND SE-LECT ONLY ONE FROM EACH GROUP  <S.2)|255  ( 5 . 3 ) p f r P lsm (5.4)  (5.1) [SELECTED SAMPLE SAWLOGS},  t  SAW SAMPLE SAWLOGS MAKE SAWSIM RUNS  —  /  7  POOL OF SAMPLE SAWLOGS WITH THEIR SAWING INSTRUCTIONS  ,  _ M FIND EOUIVALENT SAWLOGS / Y OF EACH BOOMLOG / WRITE A DATABASE T A B L E /  DATABASE «! CONTAINING ALL BOOM LOGS AND CORRESPONDING SAWLOGS  (5.1)  .  2  / REFORMAT SAWING INSTRUCTIONS / / WRITE SAWING INSTRUCTIONS / / INTO DIA MATRIX FORMAT /  I  (6 21  5 2  ^(6.2)  1  |01A MATRICES j(€.11 / ORGANIZE DIA MATRICES I N T O 7 / AN EFFICIENT DATA STRUCTURE /  L (6.2)  WBITF  i  P^t»R4«:f T t R !  r  /  DATABASE '2 CONTAINING ALL DIA MATRIX ELEMENTS  r SAVE SAWING RESULTS OF SAMPLE SAWLOGS SAVE BINARY INPUTS AND RESULTS OF SAWSIM RUNS  _S2_ REPEAT ACTIVITIES BELOW FOR A CERTAIN PERIOD OF TIME: - SELECT ONE BOOMLOG - FIND CORRESPONDING SAWLOGS AND THEIR DIA MATRICES - PROCESS SAWLOGS - COLLECT STATISTICS OF MILL BEHAVIOUR RUN FLOWSIM  F L O W S I M  S2BINARY INPUT AND (6.3) RESULT FILES  R E S U L T S  1  /  CALCULATE FINAL 7 PRODUCTION FIGURES / RERUN SAWRES 1  >INA\>I RESULTS  Figure  3.2.  (6 21  F l o w c h a r t of t h e s i m u l a t i o n  procedure  24  part  i s being  Second,  about  simulation provided numbers  the  later  bucking  in  the  one  beside  sections  -  results  data,  of  the  t h e "raw  the  diameter.  the  that  sawlogs  same  lumber  sample  required  simulation  sawlogs.  yield,  The  group  size  If  c a l c u l a t e d by  using  simulating  measurement  process.  cents  per  sawlog  sawn by  SAWSIM.  to t h e i r  same  group  only  one  its  data  length  and  result  in  sawlog w i l l  group  among  can be a l t e r e d  be the  f o r the  accuracy.  into account  specifications,  of t h e  of  log  (10-15  as a r e p r e s e n t a t i v e of  selected  form  have  must  log  sawlogs are grouped a c c o r d i n g  f o r sawing  Taking  their  of  sections.  calculations  cost  the  Crosscutting a  material" for further simulation computer  to  cross  -  are  these  and  i n the  new  not a l l o f t h e s a w l o g s a r e t o be  Assuming  approximately  data  of  sawlogs  of t h e h i g h  as an a v e r a g e ) ,  i n the  sections.  crosscutting  These  crosscutting,  Because  r e f e r r e d t o by  s e p a r a t e l y by SAWSIM, t h e s e  As a r e s u l t  is  Log measurement d a t a  characteristics  to l o g cross  too.  of t h e  components  t o be c r o s s c u t a c c o r d i n g  l o g shape  interpolation.  constitute  the  sawlogs produces a d d i t i o n a l c r o s s  as  measurement  have  sawlogs  general  of t h e a v a i l a b l e boom l o g mix  up by management.  into  a  blocks.  policy  set  process.  phases  chapters  they  wants t o "saw"  chosen  interrelated  corresponding  groups c o r r e s p o n d i n g  Instead,  of  of the m i l l ,  log  simulation  d i s c u s s i o n i s to give only  the d i s t r i b u t i o n  SAWSIM i n p u t d e s c r i b e  boom  whole  D e t a i l e d d i s c u s s i o n of  in parenthesis  pond  the  structure  process.  Given  data  within  t h e p u r p o s e of t h i s  overview  log  discussed  additional  sawing p a t t e r n s  and  SAWSIM final  inputs  products,  of  machine  the s e l e c t e d  25  sawlogs a r e then sawlogs with The  sawn by SAWSIM,  their  sawing  pieces  real  mill.  flow  instructions  through  These  instructions  machine  t h e number o f a r r i v i n g  These  of t h e n e x t  instructions  format  each  have a c c e s s  produced  vs. leaving  by SAWSIM they  containing  question  sawlog,  to  pieces),  the  reformatted  into  DIA  belonging  the  data  of  dynamic  D a t a Base  the  #2  t o flow  remaining  through the  t o h e a d r i g s must c o r r e s p o n d originate. from  to  boom  The boom l o g a r r i v a l i s  t h e boom  t h e boom l o g j u s t  up boom l o g s from  Notice,  data  base,  The e q u i v a l e n t p h a s e o f s i m u l a t i o n  corresponding  instructions  t o w h i c h FLOWSIM must  i s t o be s e l e c t e d  sampling to  sawing  i n t o an e f f i c i e n t  matrix  which they  Sawlogs,  t h e number o f ways  elements.  The s a w l o g a r r i v a l  by randomly  FLOWSIM:  Therefore,  i s : which sawlog  simulated  picking  large.  s e t up t h e  from  of  amount o f d a t a  a l l DIA m a t r i x  arrival  found.  be  sawlogs,  the  arrays are organized  Having  model?  of each  a r e not i n the a p p r o p r i a t e  have  t h e number o f sample  is fairly  information  and  l o g , the piece propagation  s a w l o g s a r e sawn, and t h e number  within  machines  i n f o r m a t i o n a r r a y s , DIA m a t r i c e s .  Regarding these  the  t o the  m a c h i n e s , and t h e s e q u e n c e o f o p e r a t i o n s .  f o r FLOWSIM, hence  dynamic  log  particular  similarly  include  a  addresses  i s t o command FLOWSIM t o  t h e dynamic model,  manufacturing (i.e.,  t h e p o o l o f sample  instructions.  p u r p o s e o f sawing  make  and p u t i n t o  log  distribution.  arrived, is  must  t h e n be  accomplished  by  D a t a Base #1 c o n t a i n i n g a l l boom l o g s  sawlogs.  t h a t t h e r e a r e two d i f f e r e n t  data  bases  supporting  26  • Data  Base  selection • Data  #1  assists  and t o f i n d  Base  #2  FLOWSIM  to  simulate  boom  log  c o r r e s p o n d i n g s a w l o g s , and  instructs  FLOWSIM  how  to  saw  these  sawlogs. Beside sizes  and s p e e d s  piece and  flow,  of t r a n s p o r t a t i o n  s e t up t h e two d a t a b a s e s  data  and  equipment,  distributions.  FLOWSIM  each  frequencies.  sample  also  constitute  production rerunning and  sawlog  data. SAWRES  result  selected sawlog  sample  weights  Having process, carried  files  include:  possible  r o u t e s of  of machinery  breakdown  counts  as w e l l  also These  and i n p u t s ,  dynamics.  piece  transportation  sawlog  equipment,  inputs  times.  be made t o s i m u l a t e m i l l  utilization  FLOWSIM  and f r e q u e n c y d i s t r i b u t i o n s  inter-breakdown Having  can  these data bases, a d d i t i o n a l  FLOWSIM for  frequencies  sample  sawlog  This calculation ( a subprogram saved sawlogs  from  length  indicate the  weights itself  and  and d i a m e t e r on  sample  how many  times They  to c a l c u l a t e is  SAWSIM  were "sawn", and  include  simulation.  o f SAWSIM) b a s e d previous  runs  machines  information  was p r o c e s s e d d u r i n g the  results  both  as sawlog  provides  FLOWSIM  based  carried  final  out  on b i n a r y runs on  input  when the  by  the  sample  p r o v i d e d by FLOWSIM.  discussed  the following  the  structure  section  o u t on t h e s i m u l a t i o n  and p h a s e s  p r e s e n t s the model.  of s i m u l a t i o n  experiments  to  be  27  3.4.  DESIGN OF THE COMPUTER  The  simulation  separate  objectives.  convince  the user  the  and  to analyse  A.  w i t h two  t h e r e a r e t o be v a l i d a t i o n  runs  to  while flow  i t produces responds  the  the  behaviour  for different  markets  t o breakdowns of  various  computer  simulation  runs  are  as f o l l o w s :  Validation  1.1. H.  were d e s i g n e d  a r e s e t up t o e v a l u a t e  Accordingly,  classified 1.  how p i e c e  study  t h e c o r r e c t n e s s o f t h e model o p e r a t i o n .  runs  redesigned m i l l  machines.  of t h i s  First,  about  Second, e x p e r i m e n t a l of  runs  SIMULATION RUNS  runs.  Sawing p a t t e r n t e s t  Leach  1.2.  runs,  u s i n g SAWPLOT  (property  of  Company L t d ) . One  FLOWSIM  run  to  test  correct  piece  flow  simulation. 1.3.  FLOWSIM  processing  times,  decisions,  by u s i n g  GPSS/H. if  This  One  utilization 1.5. operation  the the  to time  correct  FLOWSIM  statistics  debugging piece  run  large  under more r e a l i s t i c  simulation.  one-log  runs  and  This cost estimate  correct  sequence  to  simulation  of  of o p e r a t i o n s and r o u t e debugging  r u n was a l s o  facilities used  of  t o check  sizes. check  and machinery  Stochastic,  simplified  check  interactive  interactive  FLOWSIM p r e d i c t s 1.4.  runs  scale  for correct  machine  interactions. runs  circumstances to estimate  to test than  t h e FLOWSIM  possible  with  t h e computer c o s t o f  s e r v e s as a b a s i s t o design  the  28  scope  of a c t u a l  experiments  2.  Market  response  3.  Machinery  Considering is  devoted  approach  was  validation runs  validation  to  runs  is  here  validate  this  employed  results  other  a  what  what  kinds of  of  these  summary of t h e s e  hand,  breakdown  problems  experiments  may  states vs.  be  of are  conditions  inputs  of  to  v a r i o u s markets,  of  the  steady  consistently  Since  the  mill  should  at simulation  primary  effect  of  the e f f e c t s of describe  of t h e above  problems.  should be  starts.  and l u m b e r - s a t u r a t e d s t a r t s ,  changes  paragraphs  distortion  which  state  machinery  the  the  controlling  The f o l l o w i n g  is  different  random  evaluate  were d e s i g n e d i n view  problem  to  and e x p e r i m e n t a l  interest. is  t h e v a r i a t i o n of  attributed  random boom l o g a r r i v a l ,  starting  the  first  starts  the  machinery  model  for  Transient  describes  model,  only  and  are  how t h e e x p e r i m e n t s  starting  It  point  On  sources i s d e s i r a b l e .  The  the  runs, Chapter 7  o u t and what t h e r e s u l t s  of these experiments  producing  aspects.  of e x p e r i m e n t a l d e s i g n i s t h a t  These  certain  of s i m u l a t i o n  given.  simulation  objective  mill  at  runs.  in detail.  breakdown, v a r y i n g  other  to  market  sources.  in  group  validation  taken  problem  FLOWSIM  first  Hence,  designing  The  response  r u n s were c a r r i e d  were.  discussed  runs.  breakdown the  solely  on t h e m o d e l .  effect  of v a r y i n g  be  minimized.  distinguished Comparison  might  lead  of  and idle  to erroneous  conclusions. The random  second machinery  problem  is  breakdowns.  the  random f l u c t u a t i o n  Considering  that  c a u s e d by  brand  new  29  machinery  is  relatively  infrequently.  enough  to  t o be i n s t a l l e d ,  produce  breakdowns a r e assumed t o happen  Hence, FLOWSIM  an  adequate  runs  should  be  sample of m a c h i n e r y  long  breakdown  events. Third,  random f l u c t u a t i o n s  sequences  of  boom  characteristics. or  at  least  and  shape, To  log  To r e d u c e  similar  could  arrival this  solve  the problems  a r e designed as f o l l o w s .  computer-time  The a d v a n t a g e  a l l of  To  of each  delivered  both  i n time  of s t a r t i n g  decrease market  runs  headrigs. the m i l l  are also  length  of  start  c a n be s a v e d .  first  to  i s that steady  w i t h an  empty  of machinery  bias,  boom  with  On t h e o t h e r  statistics  of t h i s  operating right  idle  able  be s t a r t e d  empty m i l l  state  the  be  export markets, the  the simulation  thereby e l i m i n a t i n g  As a r e s u l t ,  to  t h e random  of d e t e r m i n i n g the  the degree run  and  t o t h e h e a d r i g s a t an a r t i f i c i a l l y  simulation  runs, w i l l  sequences,  runs w i l l  of t h i s  the s i x markets  both h e a d r i g s can s t a r t  The  same  of d i f f e r e n t  i s t h e o v e r e s t i m a t i o n of i d l e  utilization.  of  shape  the  sources  demanding p r o c e d u r e  hand, t h e d i s a d v a n t a g e  beginning  log  i s to minimize  of a l l t h e s i x market  "empty m i l l " .  for  undesired  that  experiments  Simulation  by  above,  o n l y on t h e e f f e c t s  mill  and  varying  s h o u l d be e n s u r e d .  concentrate  state  by  fluctuation  - boom l o g a r r i v a l  caused  the  be c a u s e d  times  random  fluctuation  an  also  at the very  logs  will  high rate.  Hence,  a t the b e g i n n i n g of  the s t a r t i n g  idle  times of machines a t the  be  the  times of tail  end  shortened. simulation,  be one s h i f t  i n t h e case of a l l s i x market  (27,600 s e c o n d s ) .  When t h i s  length  of  30  simulation available effect  was and  decided,  computer  cost  length  sufficient  to  run  of empty m i l l  starts,  When c o n s i d e r i n g limiting  of  model CPU  w i t h SAWSIM and  time.  Translated  typical  run  terminal  connect  hours.  Thus  is  The  boom  cost  biasing  and  runs  rate  time are  of  arrive  should  200  demand,  fewer  number of a r r i v i n g different  be the  seconds  cost  of  of  one  conversational  was  about  model d e v e l o p m e n t  in a  similar  The  and  arrival,  1500 was  in  log  identical mill  in real The  To  i n the is  life,  sense  not  the  depends this  i n the  on  time  Consequently,  be d i f f e r e n t  a  sequences  higher  e n t e r the m i l l .  boom l o g s might  sequence.  arrival  at the as  ensures  f o r a l l s i x markets,  not  to process l o g s .  l o g s can  similar  times,  i s used.  log  required  the  their  Running  the  building of  log a r r i v a l  machine times  case  the of  markets.  Summarizing, minutes), w i l l  state.  about  However, t h e t o t a l  f o r model  computer  interarrival  The  markets.  costs  model.  requires  t h e number of boom l o g s a r r i v i n g  same.  the  $50.  used  the  $1000.  similar  different  that  two  i n t o computer d o l l a r s ,  time  dollars  same s e e d of a s e p a r a t e random number g e n e r a t o r  constant of  design,  d e v e l o p i n g the  l o g s o f v a r i o u s shapes  ensure  decrease  o f computer d o l l a r s  FLOWSIM now  about  the  e x c e s s o f about  that  availability  r u n n i n g and  computer  were c o n s i d e r e d .  experimental  distinguished,  vs.  All Similar  the  be  length  of s i m u l a t i o n  t h e same i n the  case  simulation  runs  log a r r i v a l  sequences  s i x runs a r e the s o - c a l l e d  will  r u n s , one  of  analysing  start will  shift  be  e x p o r t market  all  w i t h an empty used. runs.  Five These  (460 six mill  out o f runs  31  include  the p r o d u c t i o n of both  export. on  The p r o p o r t i o n o f d i m e n s i o n a l  mill  management  Finally, a  the r e s u l t s  "judgmental At  the  this  much  valid  -  if  runs  satisfactory.  it  is  basis.  not  of  possible  says to  without  observed  and  the  using  pieces  of  any are  on  results t o o many  of  C o n s i d e r i n g the  at  gross production value,  of  gaining  would  mill.  not  be  (68), d e a l i n g with be p o i n t e d o u t  that  analysis.  providing  complete  can  often  b a s i s without output  of  the  time  of  statistics,  counts,  and  FLOWSIM data  simulation:log machine waiting  equipment.  lumber mix, lumber  recovery data  be  using  p r o v i d e s comprehensive  transportation  the production data:  be  additional  statistical  judgmental  piece  would  s i m u l a t i o n m o d e l s and draw  formal  during  a  a r e the f o l l o w i n g .  design  capable  a  on  of the r e d e s i g n e d  et a l  with  analysed  the b e n e f i t  "... i t s h o u l d  utilization  statistics  value,  Second,  FLOWSIM o u t p u t  equipment  runs,  for this  Meier  on  transportation  FLOWSIM  be a n a l y s e d  during a run, the r e s u l t s  behaviour  machine  be  independent  experiment  tests".  case.  mill  throughput,  that  evaluated  statistical  describing  1/3.  not  behaviour  of  models  of behaviour  is  be  will  experimental  book  histories  this  will  based  wonder why t h e r e s u l t s o f  Reasons  the  the  The  simulation  formal  always  -  might  impossible.  about  theory,  conclusions Since  production  will  runs  would be r e q u i r e d w i t h o u t  efficiency  simulation  the reader  statistically  information  The  -  o f t h e s i x market  experimentation  t o produce  computer  lumber  recommendation  point  statistically  difficult  lumber and lumber f o r  basis".  simulated  First,  dimensional  and time  Based on volume and  e t c . , can  also  be  32  obtained the  by r e r u n n i n g SAWRES  analysis  information The roughly  free  too of  machinery  present  machinery  runs  many  of t h i s  breakdown  then  runs  the  the  loss  three  market.  because would  stochastic  The a v e r a g e  t o the breakdown-free of run the  modification  plan.  that  events  of  random s e e d s a r e d e s i g n e d  analysing  is  i s calculated.  also  machinery  period  An  designed to breakdown  The breakdown machine  of  U.S.A.  overestimation.  a particular  f o r a predetermined  i n $/hour  case  consequently, a great  only  extent  breakdown  i n the sense  t o happen"  and  Thus,  be compared  calculate  of  deterministic  production  will  output  i s to estimate  breakdown  f o r t h e U.S.A.  technique  sensitivity  runs  runs of d i f f e r e n t  deterministic  a  machinery  dollars.  Thus,  analysis.  The r u n s e s t i m a t e r o u g h l y ,  simulation  produces  run t o  "caused  runs.  infrequent  breakdown  additional  is  market  computer  when t h e m i l l  market  of  examination  the extent of p r o d u c t i o n o v e r e s t i m a t i o n i n the  require  these  on c a r e f u l  and n o t on a s t a t i s t i c a l  relatively  amount  be b a s e d  objective  breakdown the  will  ( a s a s u b p r o g r a m o f SAWSIM).  run i s  breakdown  o f t i m e and t h e  33  4.LITERATURE REVIEW OF COMPUTER SIMULATION  APPLICATIONS IN  SAWMILLING  The and  number  o f computer  production  management  describe  a l l of these,  thesis.  Therefore,  literature  is  as  sawmilling  list  i s based  and  in  o f "A S u r v e y  i s large.  To  in  Appendix  reviewing  1., BIBLIOGRAPHY the  simulation of  Systems"  "Use  (51),  and  OF  literature  i s given. of  This  Computers  partly  of O p e r a t i o n s Research (73),  the  on  the  Applications  partly  on  my  own  survey.  presented  by  major  on t h e b a s i s  other  simulation  than  i n Chapter  Applications  listing,  a  categories.  respectively  into  taken  computer  Industries"  In a d d i t i o n t o t h i s  separately  to  Processing  Products  literature  approach In  research  i s beyond t h e s c o p e of t h i s  p a r t l y on t h e b i b l i o g r a p h y  paper  Wood  briefly,  operations  APPLICATIONS IN SAWMILLING,  related  Computerized  research  even the  applications in  of sawmill  follows.  COMPUTER SIMULATION of  simulation  brief  The c a t e g o r i e s  of examples. applications  (Note  is  are discussed  that  in sawmilling,  references, are l i s t e d  10.  of s i m u l a t i o n  in  sawmilling  one of t h e two f o l l o w i n g  categories:  A.  models  Static  characterization  simulation  generally  of l o g or c a n t  T h e s e models p e r f o r m c a l c u l a t i o n s r e p e a t e d l y  fall  breakdowns.  on a l o g o r c a n t i n  34  order  t o see  different g r o u p can shape  how  various  volume  and  be  and  These  quality  Dynamic models  operations  on  has  been  mill  dynamics  greater and  analysts  research over  on  research  following. developing special  a  the  effect  simulation  static  35,  lumber  47),  degrading  dynamics;  interested  how  recovery.  take  into  i n f l u e n c e of  or  time  the  only  (group  reasons  the  mill.  sequence  of  mill  has  dynamic  Thus, priority  reason  is  the  been  than  theory is  and  necessary.  input  these  and  are  more  the  done  on  major static  ones.  changes  of  various  group  knot  had  is  managers  issue.  simulation  to  this.  i s more c o m p l i c a t e d  in category  consideration  than  mill  second  falling  M o d e l s of  "A")  performance  this  programmer-hour  research  attention  for  languages  Perhaps  internal  a  more  simulation  The  dynamic model  activity.  models  the  in  l o g breakdown  the  this  both  in  consequently,  computer  m o d e l s t h a n on  analyze  two  simulation  more  (A1)  flow  issue  Knowledge of  why  affect  recovery  model.  reasons  log  c a t e g o r i e s , much  simulation.  a  whether  in  centers.  i t requires a higher  much  the  l o g breakdown on  of  dynamic  programmer  other,  of  to  piece  There are  of m i l l  skilled  the  lumber  result  a p p l i c a t i o n s of  to simulate  machine  have been more  Simulation  of  may  considered.  above two  t o the  purpose  simulation  according  applicable  that  on  The  s i m u l a t i o n models of  Building  Therefore,  yields.  are  (group "B").  the  than  (A2)  different  paid  strategies  characteristics  are  Considering  First,  value  further c l a s s i f i e d  shape c h a r a c t e r i s t i c s B.  breakdown  the  "A1",  "A",  i n one  sawing for  way  variables  instance  log q u a l i t y through  characters.  In  or  (30, the  building  35  these  m o d e l s , one o f t h e p r o b l e m s  location sample  and t h e n a t u r e of  logs  makes " l o o k i n g knots  can  be  be  knots.  selected  the logs"  encoded  encoding process trigonometric  of i n t e r n a l  must  into  i s to determine  into  the  i s awkward.  Once  calculations sawn  concludes  the r e l a t i v e p o s i t i o n  has  that  a substantial  questions  not  "how t o saw a s a f u n c t i o n been  answered in  the l o g "  conditions As  yet.  the sawmills  not  only  to exterior  a  proof  (59,  scanner form  from high  i t .  per  million),  time  i n the l o g  the  computer"  logquality" the  relating  have  expected  i s a method o f  research  and  then  into  "looking interior  required well  make i t s p r a c t i c a l  for as  the l o g "  into  maximum high  interpretation  on-line  high  by a  special of t h e  an a p p r o p r i a t e  required  the  done by F u n t  the output  The d e c i s i o n gain  regarding the  i s being  to convert  algorithm  the c u r r e n t l y  l o g , as  category  However, t h e  of  by  of  characteristics:  into  one  but  making p r o g r a m .  However,  t o knots  (85) p r e d i c t i o n  how t o c u t t h e l o g t o  computer  making  X-ray  grading  this  recovery.  why  i s t o "look  by an i n t e r p r e t a t i o n  then d e c i d e s  in  logquality  of f u t u r e  interesting  scanner  for a decision  of c u t s  is  determined,  accurate  and coded  Williston's  81). H i s objective  (medical-type)  on  geometry ( 8 5 ) .  of  s a w m i l l s o f tomorrow,  by  information  are  knots  of t h e i n t e r i o r  This  This  the  value  a n d d e c a y be l o c a t e d  improvements into  on lumber  boards.  a  In a l l c a s e s the  A l l research  o f "how c a n t h e i n t e r i o r  knot p o s i t i o n and  impact  and the  to  theoretically  into  purpose  computer.  lead  lumber.  For t h i s  and sawn  possible,  the s i z e , the  making  program  lumber  value  scanning  time,  and  scanner p r i c e  application  input  decision ($ 1.25  economically  36  impossible. One (A2)  of  the best  i s the Best  developed  Opening  by  To  the  finished  saw  kerf  basic  released  lumber,  (17).  in  at  the  Department  yield,  this  of  advantages  this  However,  length  application make  Products  Agriculture,  of  took  into  i s available  BOF  account  to the  BOF  at  changes  from t h e  drying,  made  two  no wane a n d t h e l o g i s  simulate log.  program, e f f e c t s of  One  is its availability  of  some  in  in addition to  o f t h e BOF computer  BOF program  might  changes  includes  i t possible  the  Forest  the t h i c k n e s s and w i d t h of the  version  made  group  program  allowance, shrinkage during  lumber  A later  along  of  installations  the  sawing  program,  of the opening f a c e ,  planing  1976,  taper  possible  Lewis  w i d t h , l o g d i a m e t e r and sawing method..  cylindrical  usage.  computer  sawing v a r i a b l e s :  assumptions:  uniform  (BOF)  U.S.  lumber  the l o c a t i o n  following  dry  and  Service  analyze  determining  Face  Hallock  Laboratory, Forest 1971.  known r e p r e s e n t a t i v e s o f t h e s t a t i c  of  the  for public  different  computer  necessary.  A l i s t of  author  of  the  program  (20) . Still  within  group  developed a t the National (Council Africa. final that  for Scientific  "A2", a n o t h e r model named SIMSAW, was Timber and  Given the l o g data, products,  systems  Industrial  of t h e  Research),  t h e sawing p a t t e r n  and  CSIR  i n South  prices  of  SIMSAW d e t e r m i n e s t h e b o a r d s , c h i p s a n d sawdust  c a n be p r o d u c e d c o n s i d e r i n g  recovery  Research I n s t i t u t e  objectives.  either  maximum v a l u e  SIMSAW was s p e c i a l l y  or  volume  d e s i g n e d f o r sawing  i n South A f r i c a ( 4 3 ) .  SAWSIM,  (and n o t SIMSAW) a n o t h e r  representative  of  group  37  "A2",  will A  be u s e d  prominent  example  MILLSIM d e v e l o p e d Laboratory,  of t h i s  setup,  but  in  hence,  FORTRAN  various  Forestry  Service  with  i t was g e n e r a l i z e d  model of t h e s a w m i l l for  analysis  characteristic  a  given  of  either  c h a n g e s , and t o d e t e c t  flow  first  sawmill  a wide range o f written  d i s c r e t e event  user  to to  design  c a r r y out  or  problems.  compare  log  mix  Additional  of Aune's model a r e :  I t a p p r o x i m a t e s l o g shape by t r u n c a t e d  •  I t simulates  • Time  needed  regression • The  empirical throughout  point  given  This  the  •  •  a  population,  mill  Products  MILLSIM was  package.  log  "B") i s  1973 ( 6 ) . A  to include  enables  later.  (group  Forest  to  layouts.  a GASP s i m u l a t i o n  designs  features  in  model was a p p l i c a b l e o n l y  later  sensitivity  i t i s discussed  o f t h e dynamic models  l o g softwood dimension m i l l  simulation  by  study,  by Aune, when a t t h e W e s t e r n  Canadian  version  small  in this  headrig  operation  to process  cones;  in detail;  a piece  on a machine  i s calculated  equations;  duration  of  machine  distributions British  based  on  is  sampled  breakdown  time  from studies  Columbia ( 5 2 ) .  I t c a n be o p e r a t e d of view,  breakdowns  interactively,  hence,  from  the  user's  i t does n o t need t o o much knowledge o f s i m u l a t i o n  techniques; • With inch  some m o d i f i c a t i o n s  lumber  other  than 2  simulate  three  thickness;  • The model u s e s a b o u t hours  i t can produce  of m i l l  UBC, t h i s  operation.  run c o s t  about  120  CPU  seconds  to  Under t h e c o m m e r c i a l $500 ( 3 6 ) .  r a t e s o f 1977 a t  38  Based  on  constructed  the  a  concepts  discrete  " t o examine the  production  of  Forest  Products  model,  the  inclusion cutting in  of g r a d e and  Sawmill,  in  5/4  In a d d i t i o n (67)  and  lengths  predetermined statistics  weakness of  output  and  and  Company, manner by breakdown  service  utilization  which  used  distinguishes  p i e c e s produced  predetermined Another  by  the  study  "the  routine  stochastic  s e p a r a t i o n of p r o c e s s i n g  models,  time  realistic  flow  (36). in  the  late  60's,  i n FORTRAN t o a n a l y z e  times  were  of and  The  machine sizes  model  a  Log  simulated  by  estimated  centres,  processing  of b o a r d s p r o d u c e d .  One  were t a k e n  into  sizes. developed  to t e s t  sawmill  the  time  it  from  other  each  diameter  from  Aune's  mechanisms  shape d e p e n d e n t ,  functions.  simulator,  i t avoids  Springs  were:  headrig  that p r o c e s s i n g times  of p i e c e  i n F i n l a n d , was  mill  c o n f i g u r a t i o n i n the N o r t h e a s t .  in front  sawmill  special  to  model a  (36)  total  Compared  Richard's  a dynamic model  t h e model was  Another  a t Warm  routine extension  sawmill  independently  classes"  " [ s i c ] ... more  theoretical  machine  on  breakdown;  size  time;  of queues  Its  a l l four l o g f a c e s ; feedback  developed  diameters,  lumber  in  t o t h e above two  hardwood  Richard  effects  Oregon, USA.  log  routine;  particular  account  diameter  i n the p r o c e s s i n g times;  representation;  times,  the  from  inter-event  Martin  l o g s by  model,  s i m u l a t i o n model.  potential  innovations  headrig  elements and  main  4/4  the  Pine  Aune's  dynamic  p u r p o s e was  sorting  of  by  the  Jaakko  designs  (65).  demanding programming models: the class  Poyry  of  of  number log  The log of is  user. d e a l i n g with m i l l  dynamics worth  mentioning,  39  though  i t does not  Bowyer search  (53).  use  It  simulation techniques  used  queuing  o p t i m i z i n g algorithm to  operating elements  problems. of  piece  characteristics,  are  The flow, taken  find  theory  was  by  combined  Carino with  optimal  solutions  article  d o e s not  show how  caused  by  irregular  into consideration.  a to  and  direct mill  stochastic log  shape  40  5_;_  INPUT DATA REQUIRED FOR THE SIMULATION MODEL  The major c h a r a c t e r i s t i c s be  described  to  be  by t h e l o g s a v a i l a b l e  manufactured,  Accordingly, the  of t h e o p e r a t i o n  this  the  chapter  a t any m i l l  for production,  machinery discusses  and  these  can  the products  the  major d a t a  technology. g r o u p s and  r e l a t e d problems.  5.1 ESTABLISHMENT OF THE SAMPLE LOG DATA BASE One o f explains  the  simulation but,  to  prevent  concept  needed.  Boom  the  the  sample  i s described some  logs  logs  have  been  bucked  briefly  for  below,  of  the  w h i c h have  l o g yard.  i n the m i l l  model  logs  explanation  are  i n the m i l l  dynamic  been  They  are  Sawlogs  to appropriate  f o r sawing.  advance.  sawlogs Then  information a  basic  selecting  misunderstanding  which  Sample  on  is  of  of  some m u l t i p l e o f t h e s a w l o g s c u t by t h e m i l l .  logs  length  This  concepts  i n t h e woods and s t o r e d  generally are  fundamental  importance  runs.  terminology bucked  the  the  From t h i s  selected  sample  machine,  where do p i e c e s pool  they  and  sawlogs,  p r o d u c e d by SAWSIM,  particular  machine,  are  how  (time  "sawn" together  needed  many p i e c e s  go, e t c . ) a r e p l a c e d  a r e randomly p i c k e d  by with  SAWSIM  in  the sawing  to process  a  are generated  piece at a  into a "log pool".  up by t h e dynamic  model  41  and  processed  about m i l l Due a  through  fact  degree,  simulating a.  mill,  the  that  statistics  l o g shape a f f e c t s  there  are  behaviour  Sample  logs in  of  a  should  logs  available  their  shape c h a r a c t e r i s t i c s .  crook,  while  are  collected  dynamics.  to the  large  the  ovality  reasonable  the  and  two  be  true  to  r e q u i r e m e n t s when one  representatives  of  of  is  real  (or l o g y a r d ) e s p e c i a l l y  Length,  twist  performance  sawmill:  l o g pond  degree a c c o r d i n g  major  mill  diameter,  logs  to t h e i r  should impact  be  on  taper,  as  sweep,  considered  mill  to  to a  performance,  and b. real  L o g s of  c e r t a i n shape  shape f r e q u e n c i e s To  meet  process  the  for t h i s  arriving  in  observable  be  i n the  above r e q u i r e m e n t s ,  study  1. D e t e r m i n e  should  the  was  as  diameter  Woodroom  sampled  according  to  l o g boom. the  sample  log s e l e c t i o n  follows: and  #3  to  length  frequencies  establish  a  of  logs  two-dimensional  di s t r ibut ion. 2.  Assign  dimensional 3. mill  Buck  boom  Select  procedure  of  the  logs  to  each  class  of  the  two-  logs  i n t o sawlogs a c c o r d i n g  t o the  prevailing  This  selection  policy. s a w l o g s t o be  must be  " s a w i n g " and The  boom  distribution.  bucking 4.  sample  flexible  simulation  remaining  previous  part  sawlog  sawn  by  SAWSIM.  enough t o c o n s i d e r  computer c o s t s  of  accuracy. of  this  chapter  is a detailed discussion  s e l e c t i o n procedure.  42  5.1.1.  Two-dimensional  i n Woodroom #3. The  are  distribution This the  given  consideration Studies  end.  according show t h a t  length  of  calculate Appendix  taper 5.3.  v a r i e s along  l a r g e r taper  l e s s taper  of  a tree,  hemlock  This  this  5.2).  Taper,  will  be t a k e n  the  length  is  at both butt  observed  in  into  reflects  this.  stems.  cross-sections  short  study  by  The of  displaying  middle  In a d d i t i o n t o v a r i e s along the program  can  taper.  to  be seen i n  o f 26 stems c o n c l u d e d  a l w a y s had h i g h  a  model ( 5 6 ) ,  computer logs  of  and t o p  the  D e m a e r s c h a l k and Kozak's t a p e r  end o f t h e stems a l m o s t  illustrates  (Appendix  t o the f o l l o w i n g . the taper  for  5.1).  made a v a i l a b l e by  was c a r r i e d o u t of how t a p e r  western  and  frequency  (Appendix  the data  shape c h a r a c t e r i s t i c  hand  study  length  empirical  i n t o the m i l l  of logs  characteristic  characteristics,  division  have r e l a t i v e l y  diameter  a brief  distribution  two-dimensional  coming  supply  o f t h e stem.  predicting  a  log  On t h e o t h e r  portion  butt  log  Stems  shape  i s c a l c u l a t e d from  important  stem.  by  o f boom l o g s  company's  this  important  distribution  another  and l e n g t h  T a p e r a s an a d d i t i o n a l l o g shape  two most  diameter  diameter  that  the  Figure  5.1  four  typical  taper  i f one wants t o c o n s i d e r  the e f f e c t  of taper  conf i g u r a t i o n s . Consequently, on  mill  stem with need  performance,  with  l a r g e r taper  relatively for  boom l o g s  smaller  i n c l u d i n g the  and boom l o g s taper  should  without be  d i s t i n g u i s h i n g among boom l o g s  butt butt  end  of  the  end, t h a t i s  distinguished.  ' (The  of v a r i a b l e taper  will  Figure  5.1.  Taper  variation  along  the  length  of  stems  44  become c l e a r when  s u b s t i t u t e sample s a w l o g s a r e d i s c u s s e d .  s a w l o g s of d i f f e r e n t even  if  why t a p e r  taper  shape c h a r a c t e r i s t i c s a r e t h e same.  h a s t o be  distinguished.)  where  attention. logs  of  the  i n c l u d i n g t h e t o p end  taper  The r e a s o n  is  also  for this  are transported  a t t h e Harmac m i l l  of  the  This i s  original  l a r g e , do n o t r e c e i v e s p e c i a l  i s t h a t Woodroom  14" minimum t o p d i a m e t e r .  requirement sawmill  s i m i l a r sawing r e s u l t s  a l l other  However, boom l o g s stem,  do n o t p r o d u c e  Two  #3  cuts  only  L o g s which do n o t meet  this  t o e i t h e r Woodroom #4, t h e s m a l l l o g complex,  or t o the P u l p m i l l  for chip  product ion. To  determine  (denoted of  by "B") and boom l o g s  incoming  (Appendix logs  5.4).  After  can  boom l o g s was t a k e n  increases  dynamic  may c o n t a i n  5.1.2.  samples  will  represents  with  logs  no b u t t  butt  end  end ("N"), a sample  at the logdeck  show t h a t  with  of  the proportion  Woodroom  #3  o f "B" boom  the  "log pool"  from  f o r flow  dimensional  which  through  array  the m i l l ,  (Appendix  a c e r t a i n length/diameter  the  5.6).  c o m b i n a t i o n and  two t y p e s o f boom l o g s : B and N.  Assignment  o f sample boom l o g s  the questions  Woodroom  t o the c l a s s e s of the  distribution  be a s s i g n e d  provide  boom  up boom l o g s  o f a s a two  two-dimensional Now  of  top diameter.  discussion,  model  cell  Results  with  this  be t h o u g h t  Each  the p r o p o r t i o n  a r e what and how many  actual  boom  logs  t o each p a r t i c u l a r c e l l ?  #3,  at  Harmac,  cuts  l o g measurements, a g r o u p o f  w e s t e r n hemlock hemlock  stem  logs.  data,  To made  45  available data.  by  CORP., w i l l  be u s e d a s sample l o g  F o r SAWSIM r u n s t h e shape o f a l o g i s d e s c r i b e d  records. the  FORINTER CANADA  Each data  record describes  z, x, y c o o r d i n a t e s of  axis.  Thus t h e shape o f a l o g i s  entries data  as  largest  center,  angle  records  the  of l o g  cross  diameter  sections  f o r each c r o s s  Therefore,  described As  is  conflict  section.  size  needed  the  cost  compromise  true  with  sampling  boom  logs  (Appendix within  logs  for  in  ovality  and  as  many  requires  data  s i x data  t h e hemlock  format  needed.  conjunction  accuracy  for  stem  SAWSIM  The p r o c e d u r e i s  with  required  sampling,  logs. and  simulation.  and p r i n c i p l e s ,  a  The sample  so  increases  Consequently,  5.4).  Bearing  i n mind, t h a t should  "B"  boom  i n rows  are  either  of  "B" boom l o g s w h i c h  22"  (Appendix  n o t be h i g h ,  was a s s i g n e d .  the  butt  i s 56-61 % w i t h i n 23"  or  of the t r e e , thus  boom  (Appendix the  the diameter  greater  of logs logs  proportions  1 t o 4 of the " l o g p o o l "  Logs of  o f B boom  as a rough r u l e , The  of  i s assigned  t h e number o f  1:1, 2:2, o r 3:2, i n a c c o r d a n c e w i t h  5.4).  number  empirical distribution  5 . 1 ) , and t o t h e p r o p o r t i o n  "log pool"  logs  the  of t h e " l o g p o o l "  t o t h e two d i m e n s i o n a l  (Appendix  the  data  each c e l l  boom l o g p e r 50 f r e q u e n c i e s  include  was  with  i s needed.  proportionally boom  and  required  and computer  Based on t h e f o r e g o i n g sample  by  Unfortunately,  the  section  s e c t i o n t o t h e x-  from t h e s e l e c t i o n o f sample  increases of  described  data  5.5.  generally  arises  of the c r o s s  reformatting  i n Appendix  diameter,  considered  o f FORINTEK were n o t i n  runs.  one l o g c r o s s  by  one of 5.6)  proportion range 15-  diameter  always  rows 5 t o 6 o f t h e l o g p o o l  46  contain are  only  "B" l o g s .  The r u l e s r e p r e s e n t i n g  these  principles  the f o l l o w i n g : In c e l l s  149  or  o f row 1,2,3 and 4, a s w e l l  less  between  two  sample  150 and 549 f o u r  otherwise  five  sample  boom  f r e q u e n c i e s of  l o g s : B1, N1; w i t h  sample boom  as w i t h  boom logs  logs: B1,  B1,  frequencies  B2,  N1,  N2;  B2, B3, N1, N2 w i l l  be  chosen. If only B1  the d i s t r i b u t i o n  a butt will  To  three  a  boom  length taken end  of  given  boom  by m i l l  i n t o account  in  Appendix To  For  log  o f l e s s t h a n 150; be s e l e c t e d .  pool to  contains the  The d i a m e t e r  the corresponding  important  boom  ovality  original  and  length  d i a m e t e r and  shape c h a r a c t e r i s t i c i s  shape c h a r a c t e r i s t i c s  and t w i s t were sampled  formed a c c o r d i n g  boom l o g c o d e s c o n t e n t  a  butt  such  as  randomly.  t o t h e above r u l e s ,  o f 84 c e l l s ,  i s displayed  5.6. boom l o g d a t a  s u i t a b l e f o r the two-dimensional  o f Woodroom #3 FORINTEK  was d e s i g n a t e d  be  log  proportional  Other  a p a r t i c u l a r boom l o g ,  FORINTEK  frequencies  management.  log pool",  designate  distribution  one sample  B1, B2, B3 w i l l  logs  end.  sweep, v a r i a b l e t a p e r ,  i t s sample  only  by d i s t i n g u i s h i n g between boom l o g s w i t h  butt  "boom  i s i n row 5,6, t h a t i s  o f t h e boom  Taper as another  and w i t h o u t  with  with  l o g , must be w i t h i n  cell.  The  then  sample boom l o g s  number  frequencies of  for cells  summarize, e a c h c e l l  certain  in question  end l o g i s i n v o l v e d ,  be c h o s e n  otherwise  cell  data  randomly.  stem  were  studied.  stems were s e l e c t e d and one o f t h e s e  I f no stem c o u l d  for a particular c e l l ,  " m a n u f a c t u r e d " by  data  extrapolating  be  found  from  t h e n boom l o g d a t a  the  diameter  while  the  had t o other  47  shape  characteristics  twist  remained unchanged.  listed  in Appendix  5.1.3.  Bucking  bucking  policies  value.  into  length  3.  Japan  (4 X  These  out of  factors width  North  the  mill  bucking  i s to c r o s s  production  the  (Appendix  management  of  5.8)  maximum  minimum  headrig  cut  sawlog  carriage),  were s e t up  for  below.  Africa  (lumber  of  1 13/16" t h i c k n e s s ) ,  and  the  schedules  l e n g t h of  the  are  The  summarized  are  given  t o the  log  (and  expected  l o o k s up  bucking  expected  cant  i n Appendix  w h i c h were c o n s i d e r e d  bucking cant  operator width  l e n g t h s and  in  carries  w i d t h s as a f u n c t i o n  5.9.  In t h i s  when d e t e r m i n i n g  the  Apppendix  expected  cant  are a l s o d e s c r i b e d .  minimized, number  the  the  of  of  their  that  the  contains  i s even  number of  and  number  fact  log pool  sawlogs  of the  schedules large  are  4).  Despite  think  of  lumber  schedules  cross cutting.  diameters  to  knee d i s t a n c e s on  of U.S.A. m a r k e t ) ,  the  according  Kingdom, J a p a n  bucking  b a s e d on  the case  by  groups  1. U.S.A., U n i t e d and  boom l o g measurements  #3  b a s i c concept  bucking  t h r e e market  France  z coordinates), ovality,  i n t o c o n s i d e r a t i o n lumber p r i c e s ,  three d i f f e r e n t  who  The  (determined  2.  of Woodroom  sawlogs a s s u r i n g  Taking  y,  Examples of  cross cut  policies.  boom l o g s  (x,  5.7.  Boom l o g s a r e  the  sweep  174  larger.  number  s a w l o g s t o be  boom  boom l o g s .  was  Obviously  the  different  s a w i n g p a t t e r n s , we sawn by  logs  In a d d i t i o n t o t h i s ,  lumber m a r k e t s , t h e i r  different  of  SAWSIM.  end  if  we  bucking up w i t h  Consequently,  a  the  48  computer raises by  cost  o f sawing  t h e need  a l l t h e s e s a w l o g s would  for decreasing  t h e number  be  high.  of sawlogs  This,  t o be sawn  SAWSIM.  5.1.4.  Sawlog  The in  selection  problem  mind t h a t  simulation.  f o r SAWSIM r u n s  of sawlog  t h e fewer In o t h e r  selection  t h e sample  must be s o l v e d  logs  the l e s s  by  keeping  accurate  words we have t o d e c r e a s e  the  i s the  number  of  s a w l o g s but a t t h e same t i m e we must t r y t o m i n i m i z e t h e l o s s o f accuracy. The  following  problem. there  After  are  only  of  information  It  h a v i n g bucked  sawlogs  one  already.  of  sawlogs  others sawing  i s up t o us we  can  setting  up  appropriate  what  we  boundaries  to  the  less  whose is  lost  sawing  cells. Appendix  by  set  up  As an example, 5.10.  It  The  by  the  the  if  sawing one sawn  sawlogs. within  can  be  and  Within  The n a r r o w e r  t e n columns  assigning cells  the c e l l  width,  of  selection table  the sawlogs similarity  t a b l e and i t s  i s displayed  f o r lumber  by  these  The d e g r e e  selection  a certain  controlled  process  sawlog  For  f r o m a "N" boom l o g  a c c u r a c y , but t h e fewer  a sawlog has  sawn.  falling  cells.  similar.  by  sawlogs,  characteristics,  similar  selection  by SAWSIM c a n be s a v e d .  eventually  to this  by SAWSIM c a n be r e d u c e d .  sawlogs  these  in simulation  shape  substituted  similarity  the  s a w l o g s can be c o n s i d e r e d  be  solution  into  and o r i g i n a t i n g  of  for  major  mean  that  The d e g r e e cells  be  interval  logs  should  of sawlogs  say  l e n g t h and d i a m e t e r similar.  can  a possible  t h e boom  having s i m i l a r  these  Thus,  instance,  are  procedure o f f e r s  in  l e n g t h s and 12  49  rows of  diameter c l a s s e s .  By from be  grouping  each group,  reduced  this  The This  the  c o n s i s t s of first,  and  at  point  bucking  bucking  linear  discussed  the  the  model  misjudges always  the  j u d g e s the  an  agreement  and  as  a consequence,  always  the  be  same as  length.  sawlog  the  of  5.2.  This  bucking  part.  sawlogs  of  from  l a r g e end  the  required  measurement This  data  is carried  computer  of of  out  by  Young p r i v a t e in  butt  of  the  determined  in accordance with  the  otherwise  the  be  from the  bucking  the  end  end  e x p e c t e d by  the  c r o s s cut  a  at  of  (i.e., saw  the saw  was more the  never  boom l o g s ;  cut  boom l o g s  i s not  is  operator  of  cross  i s cut  policy  because  width c o r r e c t l y  which  this  This  saw  diameter  always c r o s s c u t s Obviously,  policy  and  performance  program,  cut-off  headrig  cant  mill  incorrect.  bucking  small  the  outline  is  This  that  between  assumes t h a t he proper  measured  expected cant  is  can  input.  of  l e n g t h and  SAWSIM  program  will  accomplishment  one  Figure  i s the  into  distance(s)  mill;  I t assumes  seen as  section(s).  i n s e c t i o n 5.1.3.  following.  d e p i c t i n g the  1-4,  corresponding  d i s t a n c e s must  by  accurate  Block logs  s u p p l i e d as  of  be  only  sawn by  i n t e r p o l a t i o n (Kozak and  Bucking be  policy  predicted  by  cross  selecting  parts.  distances  The  5.11.  Bucking  can  major  boom  bucking  curve  boom l o g must  the  two  depicted  communications). Appendix  flowchart  It also c a l c u l a t e s  SAWSIM f o r t h e three  A  then  s a w l o g s t o be  selection algorithm  boom l o g .  also  number of  section cross-cuts  number  he  s a w l o g s , and  substantially.  sawlog  algorithm  the  similar  that there  operators  headrig  is  operator).  It  to  always the  sawlogs case.  of  50  Start -t>(Take one boom l o g Buck boom l o g i n t o a s many s a w l o g s a s r e q u i r e d by sawing p o l i c y .  No  Yes  Q Take one s a w l o g  Yes  2±  Based on t h e d i a m e t e r and l e n g t h p u t t h i s " B / r sawlog i n t o t h e appropr i a t e c e l l of " B / r s a w l o g selection table.  Figure  5.2.  Flowchart  Based on t h e d i a m e t e r and l e n g t h p u t t h i s s a w l o g i n t o t h e appropr i a t e c e l l of sawlog selection table.  of sawlog s e l e c t i o n  procedure  13 . Put t h i s sawlog i n t o f i n a l boom l o g t a b l e w i t h sawing instruction.  S e l e c t randomly one sawlog w i t h i n t h i s c e l l and p u t i t i n t o f i n a l boom l o g t a b l e w i t h sawing i n s t r u c t i o n . S u b s t i t u t e a l l other sawlogs w i t h t h e s e l e c t e d one.  Yes  Figure  5.2.  F l o w c h a r t of sawlog s e l e c t i o n  procedure - con'd.  52  B  15 Take one c e l l o f sawlog s e l e c t i o n  "B/l" table 18  Put t h i s sawlog i n t o f i n a l boom l o g t a b l e w i t h sawing instruction.  S e l e c t r a n d o m l y one s a w l o g w i t h i n t h i s c e l l and p u t i t i n t o f i n a l boom l o g t a b l e with sawing i n s t r u c t i o n . S u b s t i t u t e a l l o t h e r sawlogs w i t h the s e l e c t e d one.  Figure  5.2.  Flowchart  of sawlog  selection  procedure - con'd.  53  19,  The  second p o r t i o n of the f l o w c h a r t  is  the  sawlog  computer p r o g r a m and  taper  runs.  result  sawlogs Figure  5.2).  originating large  that  two  groups  a r e sawlogs  these  groups,  characteristics, two  separate  and  sawlogs  principles The  of  diameter  particular  cell  predetermined sawlogs can  on  low t a p e r  randomly the  "saw  cell  a r e branded  this  cell"  The  selection within  of  shape  of one o f t h e large  taper  belonging  to  table  are  within  particular  cell,  a  as  far  as  12 and 17 s e l e c t selection  to i t .  are  one s a w l o g and  sawlogs  attach  from  this  s e l e c t e d sawlog of  Finally,  sawlogs  the f i n a l  boom l o g t a b l e  boom l o g t a b l e w i t h  results  only  tables  A l l other  a  i n f o r m a t i o n , and  SAWSIM  the " s u b s t i t u t e i t with  a r e put i n t o  final  The s a w l o g s  of  t h e same SAWSIM  of t h e sawlog  instruction.  instructions  In t h e s e c o n d  cell  sawlogs  Therefore,  i t " instruction with  of  sawlog  i s why B l o c k  from a c e l l  sawlogs  i . e . sawlogs of  8).  Sawlogs  the  are handled separately, although the  s u b s t i t u t e f o r each other This  are  d i a m e t e r and l e n g t h  tables.  a r e assumed t o p r o d u c e  concerned.  there  the a p p r o p r i a t e  length  the  limits.  groups  6 of f l o w c h a r t ,  end o f a stem,  their  f o r SAWSIM  p r o c e d u r e a r e t h e same.  and of  program  7)  (Block  detailed  and s a w l o g s o f s m a l l  t o a s "B/1" s a w l o g s .  selection  of s e l e c t i o n  (Block  butt  a r e put i n t o  sawlog  sawlogs  d e c i s i o n block  o f low t a p e r  based  the  5-  on l e n g t h , d i a m e t e r  selects  runs,  group  referred  group there two  Based  program  (see  In t h e f i r s t  and  5.12.  SAWSIM  from t h e extreme  taper  The c o r r e s p o n d i n g  s a w l o g s of l a r g e t a p e r  in different  into  part.  i s i n Appendix  of the sawlog, t h i s  Assuming  taper  selection  ( F i g u r e 5.2), Blocks  with  their  sawing  (Figure 5.3).  t h e s a w l o g s and t h e i r  sawing  54  •»»•• • Ct • -  n n «•«-•»»  .. - - !  Cf r-t • g):l  •  fp  •  ~ — — • «-••»  •  B  B Z Z -j • a • tp • O n u» — — i f i —n — - — — ~" — "  zz« zz 8  :B B * B Z Z Z Z  * -P * f- K K r» UI <JM —ftp*— n — ft<r-  U  •  B B O I Z Z Z •  •u n rt ft ft n n n n n  —•ft• " • • C Mft— — rt B s z  • • • •  z •  z  w a a a a  ci rt rt rt rt rt rt  DM  Z CD Z  » z a n z  z  • • rt rt rt • n * • i n n c i • •>*• n • • — — — • — • ci  • • zz  * • i *  • • n O c. B  •*• a rt O n  • • O rt  zz  • a o • n • • 8 Z  .  v rt rt r* rt a z B z • •  — • • a • •  ar t .• — z « • • • J a — a w a w a w  ft ftftft a z B Z  U  Jz• • • • •  z • a * i— rt rt — -Cb a a a — « r» •»» r» n o •<-«•»» 8 a a a a z a z Z z  _j — — — r» c i n n n — •»*  • • <• • • rt — « • • Z Z  • Cl •  o • n • j u O UN a  •  • •  _) — PI  z  ft  mj •»••»» tr •«  J_ <• —•ft•ft•— tu O O O O u —  UJ n n n n  -  '8 a Z  8 8 Z Z  j * • ••  a • « Z  a  •  Z Z  •:•  • • •.• « — ft ft CI ft— uj a a a a a a a a  ' «  a  »z  - n n : •« a a f r - a a o  u •» «r •»•»•»» •» a a z e Z z  • a a •» o • - v» Z Z Z J • • • • — o O O O o ^ * •» •«  l_iu ftc« — • • o n n n ci • •• r* a a a «r a • • «« n«« Z Z Z Z Z ^ • • • • a * B ^ ~ rt rt rt n — w a a a a a a a  " PI -ft-ftN| •ftft—  zzz  • •  a  :  r»- n tn a <v  . «a • — — — n .j -J ui u  • a z z • • • t —ftc« a a a a n n n n  a Z a  z  • r* • 49 • _i — •« -f • • n •  « •* n •  n m m -I • • • •  _ - r i r« — 1*1 n n n n o r i r i r< n  u n n  • • • •  _ftft—  z  n • -j • •  kwftc a n n urtftftn  h i •>•!». fu n n n n  rt  • r t r* • • rt n • • a a • a ••*-••- • n • a B • :  -!•••« J — C* Ct  o n o n n  8 Z 8 Z •»- ft n >r  *a  •»••*-•»• o a a a z • z • * • • a n n n PI —  a s 8 a Z z z  ft « Z - Z • ..J • • • • J ft ft  l> 8 : 8 » i d • —•-•»in • Z Z  a  a a 8  5.3.  mn n n n u o n n r>  a z  — ft  • zzz zz -i — — — uiftftftft  igure  a a z z i  ft  j : •  — ft n •* a t  • rt rt rt • rt rt rt-. a — a ^ •« a— — n • a a z « • ft • ft • — » .•> j — in -« tr u n n n n  •  • * zz z z a • ••« z  BZ  u r> n rt r> r> (T) m kf) z z  O ft ft ft ft  • ft ft CIftft• :• • r iftr* o a • • « — — *- •» n • • • • ••- -» •  •  • • « • .j • _j«~  _lftft— 441 — — u;mm  zzz• z  • • • - • • • :• a • — n rtn rt n —- — > a a a a a a a a i w r» r» r» n n r u n  • 4«r« rt • —  • f i n t a • — n • e> 8 z _1 • • • •  -l§* •»»••>» •»  z  • rtin n ft — w • ft r* ca n ; a a ft • • — ft • • z a .j • • * •  • - n n •»  r* rt o n r> a :  1 8 8 Z 8 B O • •* • w - • z • z  « • — — a a n t% rt — Z Z  . MP* — ' • 00« -iui•rW »W•P»•»*••fc ' 8 • •  n  • • a r» r» i n — « - • •» • * Z 8 2 Z i  :  «  «J — r » n f t c » — * J  UI  •ft— — «- • ': .W J — — zzzz • » * z z z J • • I I o r> ft B • B B B • I •• : U ft rt f* rt n « n ft — ct n — f t B a z a z: a a a a r* rt r% r* rt ~ «- « B Z 0=8  • • Z • Z 2 1 Z Z •  _••»••- mm n « n ri ci •  > • 'B O B -« n o n 8 • • — Ntt a «  — — ft •  a a z z •» n r> <* a i  n i i- a a o  a  U ft ft  z :  a-Z  • c i n •» a i  Sawing  instructions  i n the f i n a l  boom l o g t a b l e  c to cn «  CO CO  NI39I-N1J81 1 3 3 4  CELL43 BMSI****** N143I-N1903  D> *  I 3  3 LQ  CELL44 B1441****** N1441******  CELL4B BMBI****** N14S1*N1471  CELL4S 81461 N146I*N1471  CELLBO BiSOl****** B1SO3*N1S03 WBOS****** N|B01******  CELLBt B1BI N1S13-B1B33 B1512-N1502 N151I-  CELLB3 B1531****** B1933****** N1533******  to cn  I ort  o o 3  *  a  CELLS? B1S71****  CELLSS BI981-  O  1 a  - 0)  4  3  CELL49 B1491****** BI493*B1B33 N1492*N1902 N1491-N1B22  NI52I......  CELLS3 BIS3i****** B3331****** N1533****** B1B33*N1B03 B2832*NtB02 N2S32*N1S02 N1531'N243t N2S3I*N3431  CELLS4 8194 1 . « » » . * N1S43****** BIS43*NI441 N1941-NI281  CELL98 BIBBi****** N1S93****** B1553******  CELLSO B1S91****  CELL60 B1601*"*  CELL81 B1611**** BI612****  CELL63 B1631*"* B1633****  CELL63 81631 B1632*81843  CELL64 B1641 • B1642*8165*  CELL6B B16S1**** B16S2****  CELL66 B1661 • Bi<662******  CELL67 81671 B267i•••••• B3671* 81673*81693 83672-B1652 83673*81663  CELL68 B168I • 'Bissa****'**"  CELL69 B1691-**'** Bi69a******  CELL73 B1721****  CELL73 B1731****  CEIL74 B1741****** 81743*81783  CELL79 ,7 ......  CELL7C B176I B)762*BI792  CELL77 BI771****** B1773-B1793  CELL82 B1821****** Bi822*B17B2  CELLS? CILL94 BI831****** B1S41****** 81B32-B1843BJS43*'*****" 81833*81842  3 i  6 1 3*  CELLIt B171I****  a 1  3  cr o o 9  O vO  CELL78 BI7B1******  a Bi7ea«'«*** a  4  •  N143I* CELL49 B148|.««««* B1482*N1413 N1482-NI413 N14BI-N1922  r f »-•• Ol 3  tr tn  CE1147 BU7|......  B  1  7  CELL79 ,...... 0  Bi793******  CELLBO 81801 • «11802 -81783  B1472****** NI471******  B  5 )  S17S3-***** CELLS 1 8)811 Basii**»*»» B3B1I****** 83813*81793 B38i3*B1793 B18I3*B17S3  Ntssi*Na43i  CILLB8 SiBSI****** NIB63*N12«1 81862*81983 NI9«1*N1281  CELLTO B1101****** BiTda**''*** B170a  Note: I f there a r e f i v e a s t e r i s k s on r i g h t hand s i d e o f e q u a t i o n s i g n , then t h e sawlog on l e f t hand a i d e i s t o be sawn. I f there i s a sawlog code on RHS then t h i s i s t h e sawlog t o be sawn i n s t e a d o f sawlog on LHS.  cn cn  56  instructions simulated  provides  by  SAWSIM.  SAWSIM t h e dynamic pick  the  boom  frequencies 5.1).  flow  logs  at  10000.  and  Step  a  uniformly  Select 1.  3.  The dynamic model must corresponding  one  to  table  o f t h e boom l o g p o o l distributed  i s N102  Look up t h e sawing  substituted  "pick-up"  provides  5.6)  random number between Therefore,  be p i c k e d  Cell  sawlog N1021  with  sawlog  4. Look  the  f o r t h e dynamic The  only  up  final  #2  the c e l l  (Figure  5.3).  B2122.  selected  log, selected This  instructs  ( I f t h e number o f s a w l o g s t o  flow  sawing  in a  this  sawlog  Varying selection  model  information  o f B2122 and u s e a s  model.  reduction  s e l e c t i o n method  the diameter  be  cluster).  boom l o g t a b l e c o n t a i n s  sawlog  is  i s c u t from boom l o g N102 w h i c h i s  316 s a w l o g s .  169 s a w l o g s have t h e "saw i t " i n s t r u c t i o n .  substantial  1 and  up.  i n s t r u c t i o n s of boom  boom l o g t a b l e  sawlogs w i l l  by  (Appendix 5.6).  one  that  log  procedure  from t h e same boom l o g i s l a r g e r t h a n one, t h e dynamic  input  the  (Appendix  (Appendix  boom l o g randomly w i t h i n  Say t h i s  only  This  random number i s 200.  S t e p 2, i n f i n a l  cut  s a w l o g s by  by s t e p example a s f o l l o w s :  one from w h i c h t h e boom l o g w i l l  that  procedure  sawn t h e sample  t h e model a g r o u p .  i n a step  Say t h i s  2.  of  random  "sawing"  i n t h e boom l o g d i s t r i b u t i o n  through  generating  in  the  A f t e r having  1. S e l e c t one c e l l  in  to  s i m u l a t i o n may s t a r t .  noted  described  the  base  A d d i t i o n a l l y , s a w l o g s o r i g i n a t i n g from t h e same boom  must is  the  o f 47%. has  and l e n g t h c e l l  Among  This  means  a  But h e r e t h e f l e x i b i l i t y  to  be  emphasized  boundaries as input  p r o g r a m makes i t p o s s i b l e t o  these  decrease  (or  again. of the  increase)  57  the  number  decrease  of  (or  decreasing table of to  sawlogs  increase)  to  simulation  be  sawn  ( A p p e n d i x 5.10)  sawlogs w i t h  from t h e o r i g i n a l  "saw  it"  instruction  by SAWSIM and t o  accuracy.  t h e number of d i a m e t e r c e l l s  For  i n the sawlog 12 t o 9,  could  be  the  instance, selection reduction  further decreased  90.  5.2.  EXPORT MARKETS, LUMBER SIZES AND  Base are  sample  lumber  defined  markets  by  the  f o r the c u t t i n g  PRICES  program  m a r k e t i n g department  of Woodroom  (50).  #3  These a r e the  following: • United  States  • North A f r i c a • Japan  -  « United  - (U), and  ( J and T ) ,  Kingdom and A u s t r a l i a  • F r a n c e and U n i t e d Among t h e above (F)  refer  markets  North  Australia,  France  markets  are t r e a t e d  market  codes  lumber  sizes  for  referring  market  Africa  codes  ( K ) , and  in paranthesis,  simultaneously. and  Belgium,  (A), (K),  Lumber United  sizes  and  on t h e  Kingdom  and  and U n i t e d  Kingdom a r e t h e same, hence t h e s e  alike.  the other  On  connection  of lumber  with  hand,  Japan,  a r e demanded by t h e  remanufacturing  construction Table  in  -  Kingdom - ( F ) .  t o two m a r k e t s ,  of  different  Belgium - (A),  purposes  (T)  there  indicating Japanese and  lumber  are  two  that  two  market: f o r the  industry ( J ) .  5.1  includes  lumber  to  markets  by  thicknesses,  their  codes.  width  In t h i s  and table,  length, data  on  58 Table  5.1. Lumber s i z e s o f v a r i o u s T Thickness (inches)  Market codes  u  1 2 4 1 1  A J T K F  9/16 1/2 1/8 13/16 7/8 3  L u  8, 8,  A J  10, 8, 8, 8,  T K  F * Note:  a  10, 10, 12, 10, 10, 10,  r  g  markets  e t Width (inches)  3 9/16, 5 5/8, 7 1/2, 9 1/2, 11 1/2 6, 7, 8, 9 4 1/8 / 4, 6, 8, 10, 12 4, 6, 7, 8, 9 6, 8, 9, 10, 12  e 12, 12, 13, 12, 12, 12,  n 14, 14, 20 14, 14, 14,  g t h (feet)  s  16, 16,  18,  20, 20,  22, * 24 * 22, 24, 26  16, 16, 16,  18, 18,  20, 20, 20,  22, 22, 22,  18,  18,  and w i d t h a r e a l w a y s  which a p i e c e  green  range,  given  by t h e maximum and minimum r o u g h  calculated  within  rough  size  Table  by a d d i n g / s u b t r a c t i n g  sizes,  5.2.  o f lumber  Data  lumber.  size,  sizes.  The  c a n be a c c e p t e d , i s These  were  v a l u e s t o / f r o m t h e rough  green  size.  t o c a l c u l a t e maximum and minimum r o u g h sizes Thickness + 1/8" - 1/16"  Among t h e e x p o r t p r o d u c t s o n l y  target  green  target  T a b l e 5.2.  Maximum Minimum  surfaced  26 26 26  n o t f o r 2x4  thickness  target  24, 24, 24,  In  this  green  Width +1/8" -1/16"  the  U.S.A. m a r k e t  case, to c a l c u l a t e  t h e p l a n i n g a l l o w a n c e must be t a k e n  requires  t h e rough into  green  account.  59  The  planing  2/16"  and  allowances  1/4",  for  thickness  and w i d t h  are  respectively.  Wane a l l o w a n c e , finished  considered  size,  i.e.,  for  the  a l l  allowable  markets  is  wane  1/3  fraction  for  of  the  both thickness  and  width. Lumber p r i c e s  considered  ones  and c o r r e s p o n d  1982,  when t h e  of  the  market the  four  market,  Table  plus  5.3.  the  Pr ices($/MFBM) Sawdust  82 (*)  Headings For  data  of  weighted prices  the  May/1983 for  prices)  its one  the  conservative  d u r i n g the  relative set  of  with  the  for  prices  350  340  245  300  390  Dry Short loq trimmings ( $ / c u n i t o f s o l i d wood) 28 82  $)  Residual (*) roundwood 82  SAWSIM t e r m i n o l o g y .  market  lumber  prices  p r o v i d e d by management, each  the  5.3?  (Canadian F  in  of  in Table  K  per  use  exception  are  of  level  lumber p r i c e s  T  to  fall  lowest  marketing department  byproduct p r i c e s ,  size  based were  combination.  U.S.A.  The a v e r a g e  market  on  are  and  as  a  surplus  w e i g h t e d by  lumber  i n $/MFBM,  production  calculated  Balance  when c a l c u l a t i n g a v e r a g e s  production data. for  are  J  were c o n s i d e r e d  corresponding mill  U.S.A.  study  A  correspond  average  Only  prices,  Planer shavings value 28  28  to  Lumber and b y p r o d u c t  Market codes  Chip  fell  by t h e  These  this  prevailing prices  decades.  recommended  analysis.  U.S.A.  the  lumber market  last were  to  in  prices i n Table  the (net  5.4.  60 Table  5.4. Lumber p r i c e s  of the U . S . A .  L  dimentional sizes (nominal)  5.3.  2 2 2 2 2  x x x x x  04 06 08 10 12  conversion breakdown  to  the  facilities will  the  machinery •  187 145 169 157 217  175 176 193 229 263  163 151 165 241 225  T 16  18  199 199 187 241 266  183 175 174 203 228  H (ft) 20 22 187 172 197 199 260  164 199 205 261  mill,  for cross cutting  machinery  will  24  210 226 229 277  be  one t w i n band  gang  vertical  and f o r t h e p r i m a r y  used  replaced  c o m b i n a t i o n machines  #3, t h e  in  the  old  mill.  from t h e h e a d r i g s t o t h e back  of the f o l l o w i n g  rotary  d e s i g n o f Woodroom  t h e same a s ones  c a n t s ) and " e d g e r "  • one I 2 " x 6 6 " •  185 179 163 145 205  used  remain  consists  two I 2 " x 6 6 "  center  12  modification  Other components of m i l l of  10  MACHINERY  According  end  G 14  N  E  8  ( C A N $)  market  by  new o n e s .  This  new  units: operable i n both  "gang"  (for  ( f o r s i d e b o a r d s ) mode, edger, resaw,  • one 4" e d g e r , and •  two 26' m u l t i - s a w m e c h a n i c a l l i f t The  modification  transportation cases.  equipment,  The l a y o u t  The  plan  of m i l l  previously  also  machinery  mentioned  between t h e h e a d r i g s  critical  part  mill  i n c l u d e s an i n s t a l l a t i o n  cross chain  equipment,  of  trimmers.  conveyors, b e l t s i s displayed  machines and  redesign  and  o f new  and  in Figure  5.4.  transportation  trimmers,  constitute  on  the  which  roll  the  simulation  85'  91.25'  "3  (-••  iQ C «-t a> cn  0*  *< O  c  CD •i o •d o in a.  s o a o  0 ) cr o 3  •o  M D> 3  63.75' M  47.5' 42.5'  • »' .1  1  1  . I • 1 J  "1  62  experiments  a r e t o be f o c u s e d .  these u n i t s w i l l  Thus,  be d i s c u s s e d b e l o w .  complete  listing  equipment  s u c h a s one new l o g f e e d e r  infeed,  two  facilities, planer  of  60-bin  specifications  of  However, f o r t h e sake  t h e new c o n v e r s i o n f a c i l i t i e s ,  J-bar  sorters  one d r u m - t y p e h o r i z o n t a l  only  crane with  at  of a  additional  the  jackladder  stackers,  packaging  c h i p p e r , a n d one  hydraulic  have t o be m e n t i o n e d .  Table  5.5. M a c h i n e  specification  data  Machines kerf (inch) 9' H e a d r i g 8* H e a d r i g Comb.machine #1 (as edger) Comb.machine #1 (as g a n g - e d g e r ) Comb.machine #2 (as edger) Comb.machine #2 (as g a n g - e d g e r ) Gang Twin Edger Tr immers  Machine summarized  0.250 0.250 0.160  400 400 350  5 5 5  0. 160  125  6  0. 160  350  5  0. 160  125  6  0. 160 0. 180 0.250  1 25 250 300  10 4 4 2  specification  i n Table  5.5.  time  data  were  of sawlines per pass  Gap and l o a d a r e used  load t ime (sec)  1 ines /pass 1 1 5  1 0 10  5  19  2 5  g i v e n by management and  The meaning o f k e r f  data are s t r a i g h t f o r w a r d . number  gap time (sec)  speed (ft/min)  time,  and machine as w e l l  to calculate  speed  a s maximum  the processing  on a machine a c c o r d i n g t o t h e SAWSIM Manual ( 2 5 ) :  63  no.of No.of p a s s e s  sawlines a c t u a l l y  max.no.of  sawlines per pass  length Time p e r p a s s  Gap t i m e machine  or  + gap t i m e machine  = time per pass * no.of  Load  time  the  among  i n Table  different  instance, 100'  the f i v e  but  size  data  The side  affecting Table  the  average  Roll  pieces  equipment  in  have d a t a  be  8.75',  conveyed  42.5',  i s conveyed  13, B e l t  6.  equipment.  For 80',  by C h a i n 9  2, 3, o r 1.  that  can t r a v e l  t h i c k n e s s o f t h e lumber  transportation  capacity,  "layer",  must a l s o  s i d e by as data  be g i v e n .  5.7 c o n t a i n s t h e s e d a t a . Turning  units,  given  2 from e i t h e r  in  summarized  p i e c e s can  on whether a p i e c e  later  equipment  transportation  maximum number o f lumber  and  are  some t r a n s p o r t a t i o n  along  between  breakdown  discussed  lengths f o r Chain 9 are  o r 115' d e p e n d i n g  to Unscrambler  feet  lengths  i s allowed  required  concepts, i n Chapter  equipment  Note t h a t  through a  o v e r v i e w , machine  5.6  t h e model b u i l d i n g  6.4.  one p a s s  time  w i t h more t h a n one l e n g t h d a t a , b e c a u s e at  time  machine.  of a c o n c i s e  here  Transportation Appendix  i f only  i s the a d d i t i o n a l  purpose  data are d i s p l a y e d detail,  passes + load  i s t h e t i m e between e a c h p a s s of a p i e c e  f o r a p r i m a r y breakdown  For  speed  t h e t i m e between p i e c e s  per p i e c e . pieces  of l o g  = lineal  Machine time  made  = —  on  t o speeds request  per minute  of  of the t r a n s p o r t a t i o n mill  management  equipment,  new  have d e s i g n e d speeds  h i g h e r than the p r e c e d i n g machine's  by t h e machine m a n u f a c t u r i n g  the  companies.  infeed  Common . t o  25  speed the  64 Table  5.6. M a c h i n e r y  breakdown d a t a  H e a d  r  i q s  9'  8' Working  Down t i m e per f a i l u r e  time  Empirical Exponential distribution distribution Average:54.7min Average: Standard 13523 s e c deviation:37,9min Numb.of o b s e r v ' s : (225.4 min) 376 O t h e r  Down t i m e per f a i l u r e  Working  time  Empirical / Exponential distribution distribution Average:54.1min Average: Standard 13491 s e c deviation:38.2min Numb.of o b s e r v ' s : (224.8 min) 376  m a c h i n e s  Down  Work  Empirical distribution Average:57.4min Standard deviation:37.9min  Exponent i a l distribution Average: 185471 s e c (3091.2 m i n )  Note: These data a r e b a s e d on t h e r e c o m m e n d a t i o n of m i l l management t h a t t h e a v e r a g e amount o f down t i m e i s 2 h o u r s p e r 15 s h i f t s and t h a t the down-time d i s t r i b u t i o n s are the same a s t h a t o f H e a d r i g 9'. T r a n s p o r t a t i o n  e q u i p m e n t  Belt Down t i m e per f a i l u r e Uniformly distributed o v e r t h e range o f 15 ± 1.5 min  Chains/Rolls/Unscramblers Working  time  Exponential distribution Average: 413100 s e c (6885 min)  Down t i m e per f a i l u r e Uniformly distributed over t h e range of 30  ± 3 min  Working  time  Exponential distribution Average: 412200 s e c (6870 min)  N o t e : T h e s e d a t a a r e b a s e d on t h e r e c o m m e n d a t i o n of m i l l management t h a t t h e a v e r a g e amount o f d o w n - t i m e s a r e 15 min ± 10%/15 s h i f t s a n d 30 min ± 10%/15 s h i f t s f o r b e l t s and o t h e r t r a n s p o r t a t i o n equipment, r e s p e c t i v e l y .  65 T a b l e 5.7. Number o f p i e c e s w h i c h c a n t r a v e l and t h e a v e r a g e t h i c k n e s s o f lumber l a y e r  T r a n s p o r t a t i o n e q u i p m e n t B l t 2 B l t 3 B l t 4 B l t 5 Rol5 Rol7 R0I8 RollO Rol12 R o l l 3  Bit! Max.no. of 20 pieces t h a t may be conveyed s i d e by side.  20  20  3  3  20  20  20  Average t h i c k n e s s of lumber layer (inches)  flow  speed  data  5  design,  time and  of  required  3  4  cross chain  5  5  The  6.4.  are  defined  c a n be c o n v e y e d  f o r them t o f l o w  5  s p e e d s a r e 10 i n c h e s / s e c .  i n Appendix  which  e q u i p m e n t Chain14 Chain!5  through.  by  t h e maximum  simultaneously These  data  and t h e  are 8 pieces  6 seconds.  left  which  thought  there  needs  of  their  special  i n Figure Their  conveying  parallel  to  (towards  chains).  Appendix  attention.  of t r a n s p o r t a t i o n The s k i d  o f equipment  d i r e c t i o n s perpendicular  layout, "COM2".  i s one more t y p e  a s common a r e a s  different  mill and  5  specifications  pieces  Finally,  two  5  a r e summarized  Unscrambler number  5 /  T r a n s p o r t a t i o n Chain8 Chain9 Chain12 C h a i n l 3  piece  s i d e by s i d e  6.5.  size, speed  piece  5.4, s k i d  length Their  can  be  transporting pieces i n other.  In t h e  t r a n s f e r s a r e coded  by "COM1"  on  (towards varying  transfers  t o each  i . e . , the length depend  equipment  to travel  whether rolls) size  along,  and  pieces  a r e conveyed  or  perpendicular  and speed data  are i n  66  5.4.  DESCRIPTION OF  After  salt  water  MILL OPERATION  storage,  elevated  to  the  b u c k e d by  two  c u t - o f f saws t o a p p r o p r i a t e  manufacturing. two  barkers,  they  are  go  After  by  ball  at  two  headrigs  of 8',  forward  carried  out.  For  headrigs.  sawn by  cut  mode t o b r e a k down c e n t e r relatively  small  sideboards  machines,  light  positioning  f e a t u r e of  cants  sideboards  and  lines the are  be  quarter  or  before  trimming.  piece  cut  live  to  only  in  s a w i n g can  logs are mill  be  split-  produces  sawn.  in either  edging  by  slab chipper  to  study,  a  c u t t i n g system.  When t h e  operated  cants,  help  and  this  logs are  combined machines can  headrig  quarter  as  transported  the  band saw  is  l a r g e r diameter  of  4x4  The  logs  in front  for  market,  band-carriage  smaller  and  the  where  overridden  i n "horns-up" p o s i t i o n .  Japanese  of  be  a single  m a r k e t s of  one from  two  are  further  can  taper-cant-sawn, the  the  oriented are  Both  a l l the  rule  for  logdeck  relatively  a single  direction.  of  are  where t h e y  removed by  whereas l o g s of  they  T h i s c u t t i n g s y s t e m c o n s i s t s of  ladder  hemlock  lengths  been  t o one  logs are  s l a b r e m o v a l and  jack  headrig  However, t h i s  screw c a r r i a g e s w h i l e  the  a  of queue l e n g t h b u i l d i n g up the  perform  the  sent  breakdown  9'.  by  b a r k has  the H e a d r i g  t o the H e a d r i g  At  the  sawlogs a r r i v e  Primary out  function  floor  discriminately  headrigs. carried  mill  boom l o g s of w e s t e r n  mode On  the  positioning.  combined m a c h i n e s e n s u r e s o r i e n t a t e d i n s u c h a way  gang to  edging process  combination The  pre-  that  both  that  their  67  edge  is  parallel  terminology, The  to  the  cants are f u l l  installation  objectives.  First,  of  size  is  i t produces  f o r both  in  the dimension up  plane.  lumber  relatively  when t h e m i l l  overseas  machine t o ensure  Cant  positioning  i s t h e same a s on c o m b i n a t i o n  The  task  edging  purposes  The before be saw  on  edger  processed  square  crosscut  i s used  headrigs It also  band  Hence  it  serves  i n gang e d g i n g  mode.  machines.  resaw  is  to  o r combined m a c h i n e s  s e r v e s a s a back  to r i p pieces lengthwise  Pieces  from  up  process requiring  machine  for  into  final  width  any o f t h e p r e c e d i n g m a c h i n e s c a n  t h e ends and form  Sideboards, to their  the f i n a l  on center  of the b i n s o r t e r s  behind  both  twin  line.  l e n g t h o f lumber  a t one o f t h e two m u l t i p l e saw t r i m m e r s  Three major  they  depending  them.  groups of t r a n s p o r t a t i o n equipment a r e used  to  t h e movement o f lumber w i t h i n t h e m i l l :  •  rollers,  •  belts,and  •  chains.  The  twin  are positioned p a r a l l e l  the workload  facilitate  of t h e  t o remove waned e d g e s .  and e d g e r ,  Second,  when combined m a c h i n e s a r e down.  trimming.  To are  cuttings.  markets.  o r down.  p u r p o s e a s t h e combined m a c h i n e s  specialized  mode, t h a t  smooth, u n i n t e r r u p t e d o p e r a t i o n when  same  at  cants  a s a " l o a d l e s s e n i n g " and  the  developing  w i t h two  low g r a d e  i s i n export  and d o m e s t i c  t h e combined m a c h i n e s a r e o v e r l o a d e d  pieces  sawmill  t h e Gang E d g e r was d e s i g n e d  mode i t i s t o o p e r a t e  primary  Using  t a p e r sawn.  i t was t o p r o c e s s  i n t o dimension  back  sawing  first  two t y p e s  o f t r a n s p o r t a t i o n equipment a r e u s e d t o  68  move lumber  lumber  parallel  in transverse  t o i t s l e n g t h whereas directions.  chains  serve  t o move  69  6^  APPROACH TAKEN IN BUILDING THE MODEL  T h e r e a r e two m a j o r  factors  affecting  mill  l o g s a r e c u t , and how many l o g s c a n be c u t o v e r of  time.  T h u s , t h e computer •  these  two f a c t o r s a r e s t r o n g l y  way a l o g i s c u t a f f e c t s simulating  breakdown  logic,  Building  requirement  the  program.  simplified truncated To  piece  Consequently, breakdown  program,  breakdown  logic,  is  in  used  must  logic  interdependent.  Hence, either  the  dynamic  include  is difficult.  t h e more time existing  logic  consuming  a log  and  The  greater  i s needed t o w r i t e  dynamic simulate  an e x i s t i n g  this  other  study.  model w r i t t e n uniform  takes taper  taper  sawing  models the  of  have  log  as a  designed  i n the past.  by H.A.  t h e l e n g t h , and  (SAWSIM) L e a c h and  accurately  than  In a d d i t i o n t o t h e u s u a l  log  elliptical  a log  t o a more a c c u r a t e l o g  l o g breakdown more  and l e n g t h  writing  s i m u l a t i o n package  SAWSIM,  into account along  procedure  and t o ensure a c c e s s  Company L t d ( 2 5 ) , s i m u l a t e s  variable  mimic  cone.  breakdown  SAWSIM  must  t o one.  f o r accuracy;  log  flow.  flow,  or have a c c e s s  a v o i d t h e time  diameter,  piece  a l o g breakdown  the  any  s i m u l a t i o n of a sawmill  period  flow as a f u n c t i o n of time.  Furthermore,  model,  a certain  l o g breakdown a n d  • piece  The  p e r f o r m a n c e : how  shape  characteristics,  c r o s s s e c t i o n s , sweep a n d hence  provides  the  most  70  accurate  l o g d e s c r i p t i o n f o r t h e computer  SAWSIM  was  Corporation) 25,000  FORTRAN  executable  incompatibilities facts,  written  in  f o r l a r g e computers.  FORTRAN s t a t e m e n t s . between  CDC  Unfortunately,  This  SAWSIM output  logic  In  6.1.  information  for  transmission 6.1).  to  FORTRAN d i a l e c t  FLOWSIM input  Problem t>|of d a t a transmission  the  the  Dynamic p i e c e flow $| s i m u l a t i o n model FLOWSIM  requiring  data  two  the  problem  of  m o d e l s had t o be s o l v e d data  input,  in a  SAWSIM, b a s e d on i n p u t s commonly p r e p a r e d ,  the data  SAWSIM  input  i n the format  preparation  and s a w i n g p a t t e r n  input  logic  model,  The dynamic model needs s p e c i a l  provide  preparation.  two  parts.  The f i r S t  and  i t s solution,  required.  was needed.  codes  was  r e s u l t s a s an e x o g e n o u s s o u r c e o f  dynamic  between  structure.  data  u s e SAWSIM  these  amount o f work.  Exogenous l o g breakdown transmission  order  over  (IBM/370-  SAWSIM  Figure  of  there are  computer  the o r i g i n a l  involved a great  breakdown  Data  IBM and CDC FORTRAN. ' B e c a u s e o f  machine), c o n v e r t i n g  necessary.  (Control  It consists  t o r u n SAWSIM on t h e UBC AMDAHL V 6 - I I  equivalent  Log  originally  simulation.  required  Accordingly, describes  Hence,  Specifically, special  this  special does not tricky  during  i s divided  the problem of data the  (Figure  t h e machine  attention  chapter  and t h e s e c o n d d e s c r i b e s  some  data  into  transmission  design  concepts  71  of  t h e dynamic m o d e l .  6.1 The d a t a following carry  •  transmission  question:  out The  THE PROBLEM OF DATA TRANSMISSION  the p i e c e  the  codes  particular  What flow  input data  between SAWSIM and FLOWSIM r a i s e s  of  information  needed by FLOWSIM t o  simulation?  FLOWSIM must  of  is  the  machine  include:  centres  needed  to  process  a  log,  •  the number of  "offspring"  •  the  of  address  the  pieces  next  at  e a c h machine  machine  centre  centre,  i.e.,  route  dec i s i o n s . •  I n f o r m a t i o n which d e f i n e s  operations  in time.  processing the  of  of  This  is  the  to prevent  a l o g on t h e h e a d r i g  board o r i g i n a t i n g  from  unambiguous  this  following  is  In  series  of  to  machine o p e r a t i o n ,  a  data  sawing p r o c e s s pattern log.  is  operations several  lines.  starts  cant  SAWSIM t h i s  Each group of is  with  a log pattern,  Subsequent  sawing,  similar  to  l u m b e r , and c a n be t h o u g h t o f  operations.  patterns  to  process  data  is  the  as  of  described  lines,  the o p e r a t i o n on the  process  a series  of  by a  corresponding  c a l l e d a sawing p a t t e r n . log,  Just the  as  final  describe  are  cant  products.  patterns  sawing  a  describing  Thus a l o g p a t t e r n  the complete  a  first  d e s c r i b i n g t h e p r i m a r y breakdown of  patterns  leading  the  log.  The way SAWSIM s i m u l a t e s  machine  s u c h as  the p r o c e s s i n g  information?  for  of  absurd cases  How can SAWSIM p r o v i d e the above  sawing a l o g  sequence  process.  and  72  Going series  into  of  type  identifies the  log  (or  generated  or  appropriate  "chain",  standard  pattern.  codes  generated  a  3 of type  cant  During  machine  is  pattern  Finally,  SAWSIM p r o v i d e s  needed  necessary operation pattern  to on  process each  takes.  the data  the  machine.  I f the r e a l  i . e . , 9' H e a d r i g ,  which  operation  l o g , and It  would  not  dynamic m o d e l .  To i l l u s t r a t e  output  i s displayed  of which  This  SAWSIM  output  3 record the  operation  o f p a s s e s on e a c h i s calculated.  t h e machines number  of  passes  how l o n g t h e  #1 and  then  the  information  a SAWSIM r u n was  generated  which  Combined M a c h i n e s  Trimmer,  in Figure  are  sawing  SAWSIM f o r the  made,  the  6.2.  does not p r o v i d e  number o f a d d i t i o n a l p i e c e s  another  i n the  required  this,  either  can c a l l  m a c h i n e s were c o d e d  the  an  i n the  also identifies  8' H e a d r i g ,  provide  the  are  one  time  which d e s c r i b e  on  3 record  required  t h e number  two  happen  pieces  cant  7-11 of a t y p e  #2, Gang E d g e r , Twin Saw, E d g e r and output  a type  of  r e s a w i n g and  i s always the l a s t  1 and f i e l d s  and  what w i l l  the  a  2 record  between  by e d g i n g ,  to this  program e x e c u t i o n  counted  position  These  from  of  1 record  A type  distance  pattern.  products  According  or  the  describes  f o r t h e machine c a r r y i n g o u t t h e  written.  are  final  p a t t e r n " which  pattern  field  this  are  machine.  a "standard  In  into  pieces  3 record  by  A type  to the sawlines. i . e . , the  A type  consists  (lines).  t h e machine u s e d , and  spacing  manufactured  trimming,  calls  saw  a sawing p a t t e r n  and 3 r e c o r d s  relative  sawlines.  the p i e c e s  either  2  cant)  the  parallel  1,  the p a t t e r n ,  specifies  to  further d e t a i l ,  at  information each  machine  about t h e center,  73  2  VL  «%»  ,O?!T  ul  T,  ua / i  lirlTL -2"'"-.I  O.BOO  uMoa  °i*  l , MW  ~  €  "  * "*»«« " <**•< «s ,  i  0  C  f  C»L ACTUAL LM  o o i«.oo aa.ao o. 110 o . o o o * r . i  u  u>  io.aa  T.JJ O.O IW.IOSHJ  •mo • • • t o a <s  * • » « • / CHIP L I M E * LM COFT COFT I  COST «  MOSS */ * CUNIT  3 ME0DG9I HECWeai C0WLV.1 COMQN01 CC-EOCJ CtMCMSa QAMCCOC TWIMSAW EDOER TRIMME* CHIPPER «% PASSES 3 » ' a 13 a •Ot SECONDS is. «• IT. IT. ac. <X *  SAWSIM  ua  PLOT  / i uHoa  axc« i o ax to i s  axio aa a X»1 0 4  ax i o aa  4  ax i o aa  I  a • x 1| 0 « •  ax i o aa  4  •  axio aa  •I-  ax to aa  ONE  I axoa aa  INCH  Figure  the  address  operations. concept  patterns route  SAWSIM o u t p u t  of the next A solution  leading  following.  Such  6.2.  to  machine  codes  to this  the  The machine and  machine  consist  using  center, problem  solution  codes data,  in  machine  or the time is  sequence of  needed.  The key  o f t h e above problem the  input  a r e t o be r e p l a c e d  of t h e code  codes  file  of  by r o u t e  of the "from"  i s the sawing codes.  machine  and  74  "to"  machine.  Figure  Obviously routes the  there  existing  network  6.3.  Network  must  i n the m i l l  chart  of  of p i e c e  routes  be a s many r o u t e layout.  Figure  codes as t h e r e a r e  To v i s u a l i z e  6.3 can h e l p .  On  these  routes,  t h i s chart the  75  number o f m a c h i n e s in  i s 13, whereas  the redesigned m i l l  this  difference  components CE2,  the  Another  machines  is  twin  which  reason  o f dummy  (TWN),  the are  and  In arrows.  twin  to to  is  machines  reason f o r  edger  that i n order  saw m a c h i n e s  and  gang  a r e manufactured  to simulate the  t o the  Twin  i s necessary.  (DTW) s i m u l a t e t h e  pieces  Twin  Saw  Saw, Thus,  flow  directly  t h e Twin Saw ( F i g u r e 3 . 1 ) .  the  f o r an  on t h e dummy t w i n  or  Pieces  additional  (TWD) and dummy  (TD1) m a c h i n e s . t h e example These  t h e r e a r e 34 p o s s i b l e r o u t e s  34 r o u t e c o d e s were t a k e n  the  input  The  results  was  used b e f o r e , but a c c o r d i n g  in  the  " v i a d r o p s o r t e r " twin  dropsorter  redirected  operation, twin#1  The f i r s t  that  resaw o p e r a t i o n d e p e n d i n g on whether through  8.  r o u t e s by w h i c h p i e c e s c a n be t a k e n  installation  the  5  i s only  number o f  o f t h e combined m a c h i n e s a r e d i s t i n q u i s h e d (CE1, CG1,  CG2).  different  of  segment  the actual  file  represented  by  i n t o c o n s i d e r a t i o n when  o f s a w i n g p a t t e r n s and machine  data  f r o m sawing t h e same l o g by t h e same  were s e t up. technology  as  t o new r o u t e c o d e s , a r e p r e s e n t e d  F i g u r e 6.4. Based  on  t h e SAWSIM o u t p u t  Dynamic  Information  Array)  sample  l o g . This matrix  c a n be b u i l t  the  number  i n connection  i s a rectangular matrix  columns a s t h e r e a r e m a c h i n e s Thus,  o f F i g u r e 6.4, a m a t r i x  of columns  involved i s 13.  in  machine  corresponding 6.5.  time  data  t o t h e above  as  with  each  having  a s many  network  chart.  The number o f rows i s t h e  number o f c o l u m n s p l u s o n e . The a d d i t i o n a l the  the  (DIA -  calculated  SAWSIM o u t p u t  last  row  by SAWSIM. i s presented  contains  The m a t r i x in  Figure  76  <X <X <X>  LOG SAWING — OFFSET — DIA LEN TAPER — S W E E P — CUFT PCS I Of NT PATTERN HOR VtR IN FT SN/FT EDGE CYL ACTUAL LBS U2 / I UM02 O.5O0 0.0 I B . 0 0 32.BO 0-110 0 . 0 0 . 0 BT.1 IS  FBM F M / CHIP LUMBER BYPRD LBR CUFT CUFT S S 3 8 3 10.S3 C . B 103.45 7.31  COST CROSS XI t S CUNIT 0.0 110.75 398 8  <% HCDRG91 HE DOG* 1 HR8-CE1 HR8-C01 HR9-0N6 HR9-TWN HRS-CE3 HR8-CS3 HRS-ONG HRB-TwW CE1-TRM CGI "TWN C01-DTW CG1-EDG CS1-TRM <% PASSES 3 3 1 <X SECONDS 33. 48. tT.  <% S  <% CE3-TRM C62-TWN CC3-0TW CQ3-EDG CG3-TRM ONC-TWN 8NG-0TW BNC-E06 OMG-TRH TWN-TWD TWN-EDG TWN-TRM DTW-TWO OTW-EOG OTW-TRM <* PASSES 4 2 7 <% SECONDS 8. IT. 14. <% S <Z TW0-TD1 TWO-EOG TWD-TRM TD1-EDG TO1-TRM EOO-TRM CHIPPER <S PASSES a 2 <X SECONDS 4  <% t  SAWSIM PLOT U3 / 1 UH03 2X08 10  3X10 16  2X10 22 2 X'l O 4 4  2X10 22  3X10 22  I  2 • X 1 I 0 6* 4 •  2X10 22  2X10 22  2X10 22  -« ONE INCH  Figure  •  6.4.  •  •*  I 2X0S 23  SAWSIM o u t p u t  using route codes  codes  i n s t e a d of machine  77  1 2 3 HR9 HR8 CE1 1 HR9 2 HR8 3 CE1 4 CGI 5 CE2 6 CG2 7 GNG 8 TWN 9 DTW 1 0 TWD 1 1 TD1 12 EDG 13 TRM Machine t ime |  4 CG1  5 CE2  7 6 1 1 8 9 10 CG2 GNG TWN DTW TWD TD1  12 EDG  13 TRM  2  4 7  1  3  2 33  Figure  From  17  16  this  6.5.  matrix  9  DIA m a t r i x  the necessary  2  o f l o g U2/1  i n f o r m a t i o n c a n be r e a d a s  follows. The c o d e s o f a l l m a c h i n e s , c o r r e s p o n d i n g a column the  having  machines  machines t h a t (HR8),  at least needed  Combined  (CG2), Edger  one e l e m e n t n o t e q u a l  to  participate Machine  process the l o g .  can  #2 i n e d g e r mode  (EDG) and Trimmer  connection (3+1)in  be  calculated  w i t h t h i s machine.  the  HR8  row,  to  a row o r  zero,  define  I n t h e example, t h e  i n p r o c e s s i n g l o g U2/1 a r e 8'  The number o f a d d i t i o n a l machine  to either  Headrig  (CE2) a n d i n gang mode  (TRM). pieces generated by a d d i n g  at  particular  t h e e l e m e n t s o f a row i n  For instance, t h i s  counting  a  number  is  4  t h e 3 s i d e b o a r d s and t h e c a n t  (Figure 6.4). The n o n - z e r o e l e m e n t s o f t h e DIA m a t r i x a p i e c e i n s u c h a manner t h a t t h e c o d e o f t h e column  the address  where t h e number  d e f i n e the route of  o f t h e next  i n question  machine i s  is  located.  78  For  instance,  means t h a t the  t h e number  2 pieces  Edger.  take  Figure  from  the center  The  last  important  matrix  the  right  according It first  Machine  having  #2  columns  are  to  edging  terminated  In t h i s  these  and  two p i e c e s  from t h e  In order  to get  from t h e DIA  carries  example,  operations  matrix  out  mode.  by t h o s e  are  the  i t i s t h e 8' are  defined  i n the corresponding  machines  gang  the  row.  Combined  The m a c h i n e s of t h e s e machines  whose  codes  i n t h e columns of n o n - z e r o e l e m e n t s o f t h e rows o f In t h e row o f CE2 t h e o n l y  non-zero  4 i n column o f TRM, whereas i n t h e row o f CG2 EDG  f r o m CE2 go t o Trimmer  Edger  to  operation.  which  f o r t h e next  U2/1,  2 and 7 i n columns o f  pieces  be r e a d  non-zero elements  (CE2, CG2) m a c h i n e s . is  edging  headrigs  (CE2, CG2) a r e s u c c e e d e d  element  are only  w h i c h c a n be g a i n e d  must  processing.  of l o g in  be f o u n d  these  of  there  #2  rules.  The machine c o d e s  In DIA m a t r i x  needing  sequence, data  operation  that  sequence of o p e r a t i o n s .  i s a l w a y s one of t h e  columns  can  cant,  to the f o l l o w i n g  Headrig. by  shows  from Combined M a c h i n e  information  i s the time time  the route  6.4  produced  DIA  2 i n t h e row CG2 and i n t h e column EDG  and  7  t o Trimmer.  by t h e l a s t  and  TRM,  only,  respectively.  there Thus,  whereas from CG2 2 p i e c e s go  Finally,  machine w h i c h  is  this  reading  the  trimmer  process i s in  this  w h i c h FLOWSIM must  have  example. The access of  number  during  sample  larger  of  DIA  simulation  matrices is fairly  to large.  The l a r g e r t h e number  l o g s and t h e number o f ways of sawing  the  number  computer memory.  of  DIA m a t r i c e s  In a d d i t i o n , t a k i n g  these  logs,  the  which have t o be s t o r e d i n into account  t h e number o f  79  references that  t o DIA m a t r i c e s  these  references  are  (transaction)  flows  transmission  i s obvious.  t o DIA  matrices  throughout  through  and  invoked the  t h e model o f FLOWSIM, whenever a p i e c e  model,  the  o f lumber  problem  of  FLOWSIM must have an e f f i c i e n t  to  their  elements  during  and  the  data access  dynamic  simulation. Before  continuing  transmission matrix  first  "j". to  rows,  store  special  are  relevant  The  last  of  pieces  between are  o f DIA m a t r i c e s ,  total  is  9-10 % ( 1 7 / 1 8 2 ) .  be  two  the  number of m a t r i x  accordance  Data  "i"  the sawlog,  t o machine  market  etc.  These  and a r e marked by time  required  transmission  Base  points  elements  to  #2  "s". to  i s low.  a subset  the r e q u i r e d element with  FLOWSIM  F i r s t , the  of non-zero e n t r i e s  Second, Data only  again, to  and  consider.  The a v e r a g e  Thus D a t a Base #2 s h o u l d  i n s u c h a way t h a t  examined t o f i n d  the  row 13 (TRM) i s u s e d  machine  i . e . , the r a t i o  e l e m e n t s o f DIA m a t r i c e s .  In  go nowhere,  In  a r e marked by " a " ,  from machine  back t o t h e p r o b l e m o f d a t a  there  occur.  on l o g d i a m e t e r a n d l e n g t h ,  of  DIA  These a r e marked by " t " .  communication  structured  locations  t o be c u t from  data  general  6.6 d i s p l a y s a l l t h e may  t o c o n t r o l FLOWSIM o p e r a t i o n  the  zero  base #2, t h e Figure  flowing  information  one p i e c e .  efficiently, density  possible  from Trimmer  row c o n t a i n s  Turning manage  these  pieces  number  process  be e x p l a i n e d .  t h e number o f p i e c e s  Since  code,  must  on t h e p r o b l e m o f d a t a  l o c a t i o n s where n o n - z e r o e n t r i e s  12  meaning  discussion  between FLOWSIM and d a t a  content  possible  the  contain Base  of Data  must  nonbe  Base #2 need  of a p a r t i c u l a r  t h e above c o n s i d e r a t i o n s  density  only  #2  to  matrix.  the approach  80  \  "to" 2 3 \ (j) 1 HR9 HR8 CE1 (i) \ 1 HR9 a 2 HR8 3 CE1 4 CG1 5 CE2 6 CG2 7 GNG 8 TWN 9 DTW 10 TWD 11 TD1 12 EDG 13 TRM s s s Machine t t t t ime  Figure  taken  4 5 CG1 CE2  7 6 8 9 10 CG2 GNG TWN DTW TWD  a a  a a  a  a a  s t  s t  6.6.  s t  General  subroutine are  DIA m a t r i x ,  which  the  column  a  a  a a  a a  a a a a a a  a s t  s t  returns  of  the  t  structure  is  required  (&VALUE),  the  t  of a p a r t i c u l a r  DIA  invoked  value.  i s the e x t e r n a l ampervariable  number  t  a a a a a a a a a a  transmission i s the f o l l o w i n g .  a subroutine  returned value  t  t  DIA m a t r i x  Whenever FLOWSIM needs t h e v a l u e  block  a  a a  i n designing the data  a particular  1 1 12 13 TD1 EDG TRM  by  The  &DIA.  element of a  name  Its4  BCALL of t h e  arguments  row number o f t h e DIA m a t r i x ,  matrix,  and  the  DIA  matrix  number.(Appendix 6.1). To DIA  understand  subroutine  following  picks  example  Assume  the s t r u c t u r e  that  the  required  matrix  element,  the  m i g h t be h e l p f u l : FLOWSIM  v a l u e o f t h e DIA m a t r i x t h e s e arguments  up  o f D a t a Base #2 f r o m w h i c h t h e  at a certain  #2 i n i t s Row  5 a n d Column  "DIA" s u b r o u t i n e f i n d s  #2 w h i c h i s LOCATN(2)=12,  and  the  p o i n t n e e d s t o know t h e 11.  B a s e d on  t h e p o i n t e r o f DIA m a t r i x  pointer  of  the  next  DIA  81  LOCATN(i)  i  1  1  • •  • •  •  k 1 2  ... ...  • • •  • • •  ...  1 2  12  •  •  •  •  •  19  •  •  •  • • •  • • •  * • «  3  26  26  • • •  • • •  •> • •  •  •  •  • • •  • • •  • • •  VALUE(k)  must  Structure  The  o f D a t a Base  range  l o o k s up o n l y  column  numbers  returns  i t f o r FLOWSIM  As a r e s u l t  of  match,  this  low a n d p r o v i d e  The written  finds  k=l9, then p i c k s  a s an e x t e r n a l  o f t h e above d a t a  e f f i c i e n t data  language.  deck The  GPSS  is  System". of t h e c o m p i l e r  Generally,  So. t h e  variable  structure  up VALUE(k)=4  and  (&VALUE).  both  to find  row a n d  the  a given  computer entry are  transmission.  s i m u l a t i o n model,  i n GPSS/H, t h e newest  developer  i n w h i c h t h e wanted  THE CONCEPTS OF DYNAMIC MODEL CONSTRUCTION  actual  Simulation  k,  #2  r a n g e , s t o p s when b o t h  demand and t h e CPU t i m e n e e d e d  6.2.  4  be, i s [ L O C A T N ( 2 ) , ( L O C A T N ( 3 ) - 1 ) ] = [ 1 2 , 2 5 ] .  subroutine  memory  1 1  5  6.7.  LOCATN(3)=26.  input  VALUE(k)  2  matrix:  GPSS  COLIND(k)  3  Figure  DIA  ROWIND(k)  the  an  "H" at  way t h e model  f o r m a t o f GPSS  following  a n d t h e computer  a n d most  developed d i a l e c t  acronym stands  program  for for  Wolvarine  "General  i s structured  of the Purpose  J.O. H e n r i k s e n ,  Software  are  the  Corporation.  follows  the t y p i c a l  (62), Table 6 . 1 .  sections  describe  the  concepts  of  model  82 Table  6.1.  T y p i c a l g r o u p s o f GPSS c a r d s and c o r r e s p o n d i n g p a r t s of FLOWSIM  the Part  •Compiler d i r e c t i v e s • E n t i t y d e f i n i t i o n and i n i t i a l c o n t r o l statements •Block statements •Report statements building.  To  readability, are  be  and  BLOCKS.  to  parts  study  major p a r t s  with  the  of  and  parts  displayed  on  The  the  symbolic  queues.  the  right  hand  of  communication  Parts  2 to  5.5  storage  initialized.  external  reader  can  of  GPSS  to these parts  are  assign  entities  numeric  equipment  and  throughout  the  directives programs  values  (Part  and  1.2)  variables  of  the  model,  matrices,  c a p a c i t i e s , v a r i a b l e s and  These e n t i t i e s  savevalues,  t a b l e s are  defined  c o n t r o l computations during  the  simulation.  Part  5.5  to  Each  block  three  relatively  #4  with  the  i s made  6.1.  1,  external  STMT#  groups  transportation these  LINE#,  together.  typical  Table  should  FLOWSIM.  functions,  actual  to  The  of  in Part  machines,  p r o g r a m becomes e a s i e r .  and  side  reference  so  6.1)  They  reference  model l i s t i n g  directives,  names  "*".  in brackets,  of FLOWSIM, numbers r e f e r r i n g  Hence,  supporting  with  h e a d i n g s of  c o r r e s p o n d e n c e between  program  (Appendix  following sections  listing  improve  listing  starting  numbers u n d e r t h e  program  compiler  In  program  model d e s c r i p t i o n and  show t h e  assure  the  comments,  Throughout of  the  cards  within  confused  To  to  make t h i s d e s c r i p t i o n e a s i e r and  numbered  not  2,3,4,5.1-5.5 5.6,6,8,9 10  (Part  9 represent  a  quadruple  sequence  sequence c o n s t i t u t e s a s e p a r a t e  9), are  small  segments,  auxiliary  #1  (Part  segments t o t h e  model  5.6),  #2  of  blocks.  segment.  The  (Part  and  main segment  6) #3  (Part  83  8)  which  i s the  the  computational  bulk  of  segment  calculates  This  block  6,  simulation will  be  model  starts.  and  mill  of  the  following  in  manufacturing  for t h i s  of  segment  i s that  this  to  flow  through  their  size  and  moving a l o n g  a  loop  where  the  and  #1  the  speed. assigning  "TIME". #2,  explain  is  the  components  cants,  this  part  actual  of  correspondence  the  mill  model i t  between  GPSS  of  raw  etc.  a  sawmill  material  to  are  be  T h e s e components  machines,  manufactured,  fall  i n t o one  of  groups: and  the  transportation sense  that  equipment  they are  are  present  "static"  during  the  whole  process.  • Lumber p i e c e s system,  this  among  components.  logs,  • Machines  i s numbered  that  needed  function  e q u i p m e n t , and  pieces  components  a  segment  the  transportation  reason  intervals  5.6  fact  Before describing  to  Basically,  two  time  Part  the  The  a transaction  useful  entities  statements.  t o MSAVEVALUE  Part  model.  despite  equipment as  i s done by  time data  the  entities  consists  transportation  of  flow  are  through  "dynamic" components, w h i c h it,  are  processed,  and  enter  then  leave  the the  system. Consequently, of  GPSS,  whereas  represent  i n the  Reverting  describe  machines  transactions,  lumber p i e c e s  simulates  facilities  the  storages,  and  as  "static"  transportation  "dynamic" e n t i t i e s  of  entities  equipment,  GPSS,  represent  model.  to Part  the  as  and  6  machinery  simulation  of  the  model,  breakdown. technique  of  The  separate  segment  following  machinery  #2  paragraphs  breakdown  in  84  FLOWSIM  and  the m i l l  management.  During g r o u p s of •  the  d a t a made a v a i l a b l e  the d e s i g n  of t h e breakdown  accordance The  two  with  the  basic  headrigs,  two  headrigs July,  August  change and when  breakdowns  breakdown t i m e s be  and  calculated  group are  by  September  were c o l l e c t e d  one  of  not  (work p e r i o d s ) a r e distributed.  of  1983.  management (Appendix to six  maintenance, times  known but  of  of for  6.2). causes:  saw/knife the  Thus t h e  shifts inter  a r e assumed  only parameter  average  existing  Down-time d a t a  recorded.  not The  the  only  corresponding  failure,  were  the  to the other  the  the m i l l  U n f o r t u n a t e l y , the a c t u a l occured  exponentially  techniques.  i n the c u r r e n t m i l l .  the e x p o n e n t i a l d i s t r i b u t i o n , was  first  o p e r a t i o n a l , power other.  from  in  down.  were made a v a i l a b l e  These down-time d a t a electrical,  work and  necessary  simulation i s to a l t e r  of m a c h i n e r y  i n the  machines  simulation  of breakdown  unit  possible states: two  t h r e e g r o u p s was  t h r e e breakdown  concept  operating  June,  major  and  between t h e s e  of a p a r t i c u l a r  The  the  three  t r a n s p o r t a t i o n equipment.  Differentiation  and  simulation  by  headrigs  •  its  recommended  t h e m a c h i n e r y were c o n s i d e r e d :  • other machines,  state  as w e l l as  to  determining  inter-breakdown  time,  as f o l l o w s :  AIBT =  where AIBT s t a n d s  (T - D)  f o r the Average  /  (N +  1)  I n t e r - B r e a k d o w n Time; T  i s the  85  total  time p e r i o d  times;  a n d N i s t h e number o f down-time d a t a c o l l e c t e d .  Based on the t i m e s by s a m p l i n g average  during  data  collection;  above a s s u m p t i o n from t h e  the simulator  exponential  inter-breakdown  time  D i s t h e sum o f down-  predicts  distribution  parameter  of  "work"  with  the  the headrig  in  quest i o n . At be  t h e e n d o f a work p e r i o d ,  predicted.  distributions the  This  which are  by  9' ( P a r t  help  as  FREQ o u t p u t  example,  relationship  between  straightforward.  constructed  exactly  two f u n c t i o n s  According  to  breakdown  transaction  ADVANCE b l o c k s periods The  the function  along  and down t i m e s  down-time d a t a  are  observed in  by  were  (Part  defining  8' and DWNH9 constructed  cards  6.2.  The  and t h i s  table  cards  and data  are  o f DWNH9, and hence a r e  discussion,  infinite  library.  Table  follower  follows:  an  empirical  down t i m e s o f H e a d r i g  DWNH8 f o l l o w e r  the foregoing  representing  second  the  simulation  cycles  from  must  w h i c h were c a l c u l a t e d w i t h t h e  t h e same way a s t h a t  here.  down-time  i n t h e model  a r e summarized  Function  summarized  machine  that  These  frequencies  an  not  sampling  o f FREQ p r o g r a m a v a i l a b l e a t UBC s o f t w a r e Based on t h e  9',  of  f u n c t i o n s DWNH8 f o r H e a d r i g  4).  the cumulative  by  incorporated  two GPSS c o n t i n o u s  for Headrig  is  i s done  the length  a  p r i n c i p l e of  breakdown  loop,  inter-breakdown  the  timer  activating  times,  i.e.,  two work  6.1).  group c o n s i s t s of brand not a v a i l a b l e .  Mill  new m a c h i n e s management  for  recommended  t h e down-time d i s t r i b u t i o n s o f t h e two combined  Gang E d g e r , Twin Saw, E d g e r a n d t r i m m e r s  be assumed  which  to  machines, be t h e  86 Table  6.2.  Summary of o b s e r v e d downtime d a t a of H e a d r i g  Down-time* intervals (min)  Frequency down-time Absolute  5 - 10 10 - 20 20 - 30 30 - 40 40 - 50 50 - 60 60 - 70 70 - 80 80 - 90 90 -1 00 100 -110 1 1 0 -120 1 20 - +  same  limits  as  that  the a v e r a g e  than  that  The  Part  6.2  transportation following  of  group  is  2  assumption  hours  per  15  6.1).  the  model  The  simulates  belonging  to  time  less data  exponentially  is  the  same  breakdowns  Group  shifts.  happens  working  concept  i s that  3,  of  with  as  the the  assumptions: down-times  15±1.5 min  unscramblers • The  are  for belts  and  uniformly distributed 30±3 min  over  the  for chains, r o l l s  and  ( b a s e d on m i l l  management e x p e r i e n c e s ) .  inter-breakdown  times are e x p o n e n t i a l l y  X (i=1,2,...,38)=(15*460*60 i The  included.  assumed t o be  simulation  (Part  of  additional  are a l s o  equipment  • Average range  An  limits  of h e a d r i g s .  breakdown  of the h e a d r i g s  lower  from down-time d i s t r i b u t i o n  i n the case  in this  distributed.  9'.  down-time  sampling  machines  .037 .218 .303 .420 .507 .595 .672 .734 .771 .808 .827 .851 1 .000  of H e a d r i g  Consequently,  of  .037 . 180 .085 .117 .087 .087 .077 .061 .037 .037 .018 .023 . 1 48  a r e e x c l u d e d and  amount of  frequently  Cumulative frequency  1 4 68 32 44 33 33 29 23 1 4 1 4 7 9 56 376  total: * Upper  with which f a l l s i n the i n t e r v a l Relat ive  9'  X values are c a l c u l a t e d  f o r one  sec)"  distributed:  1  complete  cycle  of  work  87  and  down t i m e .  to  calculate  This X calculation the  average breakdown  for  of m a c h i n e r y .  were  two  made,  calculated in  types  a very  the  AIBT  erroneously  are  distribution  two  useful  which  used  f o r machines are  employed  (When t h e a c t u a l breakdown  runs  t r a n s p o r t a t i o n equipment  were  for  the  formula  time  formula  on  page 84.  s m a l l d e v i a t i o n from what would be  There  the  simulation techniques  data by  from  inter-breakdown  because d i f f e r e n t the  differs  properties  simplify  the  This  expected  of  resulted  above.)  the  exponential  transportation  equipment  breakdown s i m u l a t i o n . First,  the  distribution:  combinative  the  breakdowns of any  distributed  with  property  inter-breakdown  of  time  X=  exponential  between two  t r a n s p o r t a t i o n equipment  r a t e of  the  is also  consecutive exponentialy  38 L X i =1 i  Secondly, probability Poisson  sampling  selective  of p from a P o i s s o n  stream  Based  the  on  of e v e n t s the  two  at  property: stream  rate  selecting  of  rate  events  X,  with  creates  a  p*X.  properties  t r a n s p o r t a t i o n equipment  above,  the  inter-breakdown  technique times  is  of the  following: 1. rate  Sample (X=IX  from t h e  ), and  exponential  distribution  of  X breakdown  then  i 2.  F i n d out  w h i c h machine b r e a k s  In t e r m s of GPSS, s t e p timer  transaction according  down, i . e . , f i n d  1 i s done by to the  generating  exponential  a  "i". breakdown  distribution  with  88  rate  X.  Step  (transporation function  2  equipment c o d e ) f u n c t i o n  assigns  probabilities. transaction equipment block  then  with  or  "breaks  is  summary, used  the  breakdown  breakdown  simulation  other  particular  piece  prediction. start  of  despite  Part  particular  i s then  inaccurate. very  of  describing different  Parameter  basis  of  the  1  the  i n Part  simulation  start  machine  contents  transportation  equipment  of  Preceding  breakdown equipment  because of the  d o e s n o t happen  the  i s predicted down.  because  f o r t h e next  that  of  a  s h o u l d be d e l a y e d  next  by t h e  the  the  "down" "down"  simulator,  In t h e GPSS model  the p r o b a b i l i t y that  of  needs  o f down-time p e r i o d  and, c o n s e q u e n t l y ,  7 solely consists  equipment, but  separate  but l e s s a c c u r a t e  it is still  ignored  segments.  i  whether t h e  realistic  i t s own  i t may happen  Fortunately,  the  i  transportation  breakdown  more  needs  This  low and i t s e f f e c t c a n be Part  t o p =X /X  sequence, e i t h e r  6.2 does n o t w a i t  Consequently, a  is  of t r a n s p o r t a t i o n  the f a c t , that  breakdown  t h e next  o f down-time.  block  This  SUNAVAIL-ADVANCE-SAVAIL  two  hand  i s simpler  Predicting  GENERATE  in  the  the  E a c h machine  the  the p e r i o d  two  on  according  selected  block  simulation  following.  for  of  operand.  f o r t h e m a c h i n e s and t r a n s p o r t a t i o n  more GPSS b l o c k s . On  the  w i t h TRCOD  i s a b e l t or n o t .  comparing  techniques  segment.  down"  "B"  1  t o the code  selected  equipment  as  Parameter  The a p p r o p r i a t e  6.2.2,  machine  to  the a p p l i c a t i o n  transportation In  codes  Corresponding  sequences.  6.2.1  i s c a r r i e d o u t by an ASSIGN b l o c k  simulation  this is  t h i s happens i s  ignored. comments the  (starting  transaction  t h e main  segment,  with  "*")  parameters i n many  at  cases,  89  it  i s handy t o  t o model  recall  as  information  along  content,  listing  of  information  l a b e l s attached  their  content  various  parameters  relevant  behaviour.  Parameters small  the  with are  (Appendix  interpretations  t o the  in  can  t r a n s a c t i o n s to  them.  in Part  7 of  Transactions  different  be  thought  record  Parameters used  described 6.1).  carriers  and  extended their  as  carry  i n t h i s model  the  segments a r e  and  of  with  program  different  summarized  in  Table  6.3.  Table  6.3.  I n t e r p r e t a t i o n of segments  T r a n s a c t i o n s of d i f f e r e n t segments  transactions  in  different  Interpretation  M o d e l Segment 1  Loop-index i n t r a n s p o r t a t i o n time c a l c u l a t i o n . Column i n d e x of m a t r i x s a v e v a l u e "TIME". I t assumes as many v a l u e s as t r a n s p o r t a t i o n equipment time c a l c u l a t i o n i s needed. The e l e m e n t s of "TIME" m a t r i x a r e used i n ADVANCE b l o c k s which simulate t r a n s p o r t a t i o n time passage.  Model Segment  Transportation  2  equipment  identifier.  Model Segment 3 (Main segment)  E i t h e r boom l o g , s a w l o g , c a n t , s i d e b o a r d , o r lumber d e p e n d i n g on t h e phase o f t h e s i m u l a t i o n p r o c e s s .  M o d e l Segment  The  Part  8  4  i s where the  place.  In  entities  i s c o n t r o l l e d by  equivalents times,  GPSS, the  of  actual  flow  of  piece  of  i n academic  flow  simulation  t r a n s a c t i o n s through  blocks.  statements  particularly  timer  These other  GPSS  computer  the  blocks  "static" are  languages.  e x e r c i s e s , a primary  takes  goal  the Many of  a  90  good  computer  statements, model,  programmer  i . e . , blocks  some  is  in  GPSS.  a s p i r a t i o n s were  hence some e x p l a n a t i o n  to  equipment  the  But  this  (e.g.  quite  time,  the model t o t h e r e a l concise  primary  goal,  sequence  these  indirect  as  obvious,  questioned.  which  can  resemblance of  model w r i t t e n  i n such a  t o debug, t o m o d i f y  the  i n GPSS  d e s c r i b i n g the system.  a l s o reduce  A sawmill  when  is  specification)  techniques  design.  this  are techniques  t h e number o f b l o c k s  Consequently,  and  to  model was c o n s t r u c t e d , t h e  t h e program w i t h  a s few  GPSS  a s was p o s s i b l e . order  in  8) c o r r e s p o n d s  transportation according The to  of  sawmill  t h e above  block  that  There  o b j e c t i v e was n o t t o w r i t e  The (Part  this  of t h e model c o u l d be  f a s h i o n , would be d i f f i c u l t  validate.  blocks  say  true.  addressing,  same  was t o keep  One c o u l d  the v a l i d i t y  significantly  the  building  number  a c t u a l sequence o f m a c h i n e s and t r a n s p o r t a t i o n  not  indirect  reduce At  is  In  the  i s required.  as p o s s i b l e .  because otherwise  minimize  i n c o n s i s t e n t with  One o f t h e m a j o r a m b i t i o n s similar  to  the  which the b l o c k s t o the  equipment  t o the r e a l  mill  boom l o g a r r i v a l "entry"  sequence through  of which  i n t h e main  machine lumber  segment  centers  and  pieces  move  ( P a r t 8.1) sends boom  logs  design. simulation  of t h e model.  boom l o g d i s t r i b u t i o n  appear  (Appendix  According  t o the two-dimensional  5 . 1 ) , boom l o g s a r e p i c k e d  up by  "BLGEN" f u n c t i o n . The selection  purpose of t h i s  f u n c t i o n i s t o ensure that  procedure corresponds  distribution  (Appendix  t h e boom l o g  t o t h e two d i m e n s i o n a l  5.1) and w i t h  boom  log  t h e sample boom l o g " p o o l "  91  (Appendix  5.6).  The  boom  calculated  by t h e f o r m u l a  R e l a t i v e frequency of = boom l o g s i n i - t h c e l l  where A B S F R ( i )  log  relative  ((ABSFR(i)/SUMAF)*0.999999)/NBLOG(i)  i s the absolute  SUMOF i s t h e sum o f a b s o l u t e  frequency  GPSS  instance, be  selects the  also  frequency  0.0051.  0.0051  and  function  required  0.0102  B101  for  (cell#1)  (Part  and  format boom  relative  functions.  The  will  Similarly,  the  these  on  the  two boom l o g s a r e  follower  cards  relative  cumulative  have  been  of t h i s  frequencies.  program  (Appendix  frequencies  t o the m i l l headrigs  s e l e c t e d , they  bucking in  in  the  of  t h e form o f dynamic  in  Data  #1.  from a g i v e n  information  This  Data  Thus  is built  s a w l o g s and t h e s a w i n g  (in  are s p l i t  into  i n s t r u c t i o n s and go t o one  clusters.  number o f s a w l o g s t o be b u c k e d  Base  frequencies  work a FORTRAN  s e q u e n c e of sawlog a r r i v a l  diameter  For  boom l o g code  f o r the f i r s t  4.3).  tedious  logs  t h e two p o s s i b l e and  from  o f GPSS.  sawlogs a c c o r d i n g  timing  interval  t h e s e c o n d boom l o g (N101) i n c e l l # 1 i s  t h e boom l o g c u m u l a t i v e  errors  After  log  that  follower cards,  contain  avoid  of  6.3) computes and w r i t e s  The  arguments  Hence, t h e c u m u l a t e d  "BLGEN" f u n c t i o n  of  of the c l o s e d  s e l e c t e d i s (102/10000)*0.999999)/2=0.0051.  relative  To  frequencies,  random  likelihood  of i - t h c e l l ,  i n the i - t h c e l l ,  0.999999 i s t h e upper end v a l u e  which  are  below:  N B L O G ( i ) i s t h e number o f boom l o g s  and  frequencies  array,  the  proper  i n t o the model. boom  l o g , the  i n s t r u c t i o n s o f SAWSIM DIA),  Base #1 e n s u r e s  are  organized  the economical  92  selection  of a r e l a t i v e l y  450/shift), of  t h e computer  number  should #1.  in  Figure  6.6.  process case.  in  an  Figure  example  Assume t h a t  returns  random  6.9.  might  boom  possible B1131,  the  l o g B113  21.  in  row  the reader  of  understand  Data  this  function  c a n be f o u n d .  selection  of  Base  These  i s t o be c r o s s c u t i n t o  mechanism  ( k = l ) a n d MODE 5 (k=5) f o r t h e f i r s t  DIA m a t r i x c o d e s , a s s i g n e d  to  Parameter  (Figure  numbers  mean  two s a w l o g s .  f o r the  of  FLOWSIM  #1  first  38, f o r t h e s e c o n d s a w l o g B1132.  t h e sawing mode s e l e c t i o n  Base  Consider the following  I n row.21 o f D a t a  37,  process i s  segment o f D a t a Base #1  be h e l p f u l .  ways o f s a w i n g a r e i n row and  1  To  (about  The a l g o r i t h m  algorithm,  t h e boom l o g g e n e r a t o r  number  logs  selection  Studying this  6.9), NSL(21)=2, FIRST(21)=37  MODE  code  for convenience, a truncated  displayed  that  boom  take a simultaneous look a t the s t r u c t u r e Thus,  that  of  time stand p o i n t .  t h e boom l o g , s a w l o g a n d SAWSIM  depicted  is  from  large  FLOWSIM  The  sawlog Assuming  picks  and second  up  sawlog,  1,  a r e U011 a n d  to  be a s s i g n e d t o  U206. Information parameters headrig code  codes a r e a s s i g n e d  and  pieceflow,  i n the f r o n t - p a r t  diameter  respectively, are  governing  of  t h e model.  t o Parameter  are assigned  and i n i t i a l i s e d  self-explanatory,  to  i n Part  however  has  DIA  1 and 2.  Length,  Parameters  8.2.  Parameters  matrix  market  7, 10 a n d 11,  Parameter 1,  and  2  7  and  11  and  10 need  to  control  explanat ion. DIA piece  matrices  flow  transactions  both  serve  as  important  information  i n t i m e and s p a c e , t h r o u g h o u t t h e p r e s e n c e o f  i n t h e model.  Thus t h e DIA m a t r i x code  i s attached  93  GENERATE A RANDOM NUMBER, i=1,2,..,NO.OF BOOM LOGS, WITH APPROPRIATE PROBABILITIES P1 <-- i ASSIGNED BY "BLGEN" (BOOM LOG GENERATOR FUNCTION).  ^_  LOOK UP THE CORRESPONDING NUMBER OF SAWLOGS TO BE PRODUCED FROM THIS BOOM LOG: N S L ( i ) P4 < — N S L ( i )  I N I T I A L I S E SAWLOG COUNTER COUNT=1  LOOK UP THE POINTER OF THE FIRST (OR NEXT) SAWLOG ORIGINATING FROM BOOM LOG ( i ) : j=FIRST(i)  I  SELECT MODE OF SAWING U ) k 1,2,...,8 (COLUMN OF MODE 1,2,...,8) =  ASSIGN DIA CODE TO PARAMETER 1 P1 <-- DIA CODE(j,k)  I  COUNT SAWLOGS COUNT= COUNT+1  YES  Figure  6.8.  ML  A l g o r i t h m of sawlog and t h e c o r r e s p o n d i n g code s e l e c t i o n p r o c e s s  TAKE NEXT SAWLOG  SAWSIM  c  BOOM LOG NUMBER  BOOM L O G N U M B E R CODE OF SAWLOGS WITHIN BOOM L O G  <D (BLN) 1  (BLCOD)  2 3  B 101 B 102 B202  (NSL) 1 1 1  20  B 2 12  2  LINE*  SAWLOG  SAWLOG  OF FIRST SAWLOG  NUMBER  CODE  (FIRST) 1  (SLN)  SMALL END OIAM.  EQUIVALENT SAWLOG CODE  1  (SLC)  ( TO IA )  (ESLC)  B101 1 B1021 B2021  14 . 9 5 B 1 0 1 1 1 6 . 0 4 B1 161 14.67 B2021  2 3  2 3  35  35  B2121  16  37  36 37 38  B2122 B1 131  15 17  B1 132 B1 141  15  DIAM.OF EQUIVALENT SAWLOG (DIAES) 14 . 9 5 16.75 14 . 6 7  MATRIX  DIA MODE 1  (MODI)  MODE 2  (M002) U 48 U 49  U U  1 2  U  3  U  50  MODE 3  (M0D3) U 95 U U  96 97  OF MODE 4  (M0D4) U142 U143 U144  CODES M0DE6  MODE 7  MOOES  (M0D6)  (M0D7) U283 U284  (M008)  U236 U237 U238  U285  U330 U331 U332  U199 U205 U199  U246 U252 U246  U293 U299  U340 U346  U293  U206  U253 U247  U300 U294  U340 U347  U254  U301 U297 U294 U297 U297  MODE 5  (M0D5) U189 U190 U191  Pi  X ft  n rt  o  21  rt  22  W  23  B1 13 B 1 14  2 3  39  0) 0> VI (0  39 40 41  B 2 14  3  42  42 43 44  B1 142 B1 1 4 3 B2141 B2142 B2143  20 18 16 19 17 16  55 B2121 06 B2122 1 1 B2121 2 7 B1 132 85 B137 1 64 B 1 2 4 2 38 50 82 33  N2282 B137 1 N2282 N2282  16 15 16 15 20 18 17 20 17 17  55  U  1 1  U  U U  17  U  58 64  U105 U 1 11  U152  06 55 27  1 1 18  U U  58 65  U105 U l 12  96  U U  79  U  12 19  U U  59 66  U106 U113  U152 U159 U153  92 96 92 92  U U U U  15 12 15 15  U U  62 59 62 62  U109 U106  U U  U109 U109  U158  U160 U156 U153 U156 U156  U200 U207 U203 U200 U203 U203  U250 U247 U250 U250  U341 U348 U344 U34 1 U344 U344  VO  95  to Parameter is  the  value  1.  answer  to the  c h a n g e s as  to  machine.  and  6 depending  Japanese  Since  the  total  the  on  and  blocks,  the  carried  this  by  calculated:  Parameter  mix  value  parts  of  lumber various  before  main  at  provisions  move i n t i m e , a c c o r d i n g  The  time  automatically  required to  process  c a l c u l a t e d by  data  SAWSIM.  These s p e c i f i c a t i o n s of  provided  lines  machine time data  per are  by  the  pass, then  a  gap-  calculate as  and  transmitted  sawlog  of  MSAVEVALUE  the  1.  two  sawlog  whose  The of  from  number  elements interest  of are  8.5  to  that  the  and  the  pieces  flow  machine  piece  that  system. at  a  machine  l o g l e n g t h and data  machine time.  t o the  a  require  made t o e n s u r e  designed  load  8.15,  Both m a n u f a c t u r i n g  be  lineal  logs.  a  specification  are  5  recovery.  SAWSIM b a s e d on  machine  to  element  i t to  to the  4,  African,  e a c h machine c e n t e r  must  3,  Whenever  machine.  transporting  Consequently,  number  the  2,  serves  t r a n s p o r t a t i o n equipment  arriving  its  machine  breakdown of  array  segment, at  1,  known l a t e r  volume  from  North  when s t a t i s t i c s  processing  a t a machine and  pieces  primary  savevalue  and  Hence,  system  i s i n c r e m e n t e d by  product  of  time.  1,  weights  operation  the  that  market.  savevalue.  as  the  French  t o be  matrix  ?".  t o USA,  t r a n s a c t i o n moves i n t o one  Additional  piece  matrix  the  go  one-dimensional  serve  simulate  the  simulate  corresponding  array  through  a  a  representative  8.4  or  I going  market c o d e s of  pieces  s a w l o g s has  production, via  the  " t o " machine c o d e ,  through  10 c a r r i e s  UK  the  "where am  flows  whether  number of  counter  piece  J a p a n e s e #2, 8.3  2 carries  question  Parameter  #1,  Parts  is  Parameter  input  speed, The  is  other  file  of  maximum  calculated  dynamic model  via  96  DIA  matrices. In  The  GPSS, p a s s a g e o f  A o p e r a n d of  transaction time.  "A"  P1  carries  &DIA.  are  the  The  on  the  matrix  •  the  size  • piece  of  route  the  of  the  light, As going  the  (Part flow  the  with  machines,  a piece.  value  Their  returned  DIA  by  matrix by  machines.  P2  code  changes  Parameter  #2  7.1.2).  through a given  transportation  equipment,  t r a n s p o r t a t i o n equipment the  piece of  less  the  flows  and  Twin Saw,  Chain  through  #7  route  Consequently,  travel  affects conveying  v a r i e s as  a  i n the  However,  the  f u n c t i o n of  the  mill.  equipment  obvious:  size  Thus, into  #7  (Figure  5.4).  come from e i t h e r Combined M a c h i n e  Thus, d e p e n d i n g on  Chain  is  to  proper  i s needed.  example, c o n s i d e r  to the  speed  time needed.  through  transportation  some e x p l a n a t i o n  piece  of  t r a n s p o r t a t i o n equipment,  or Gang E d g e r .  how  required period  column number d e n o t e d  t r a n s p o r t a t i o n equipment  effect  an  a  v a r i e s as  transportation  speed,  a particular the  a  how  length.  effect  size  with  to d i f f e r e n t  to  the  block. long  conjunction  value  ADVANCE  on:  s p e e d of  higher  way  the  required to process  returned  required  of  in  by  simulator  to simulate  The  the  the  time  the  ampervariables  •  The  up  blocks,  their  depends  i s provided  "tells"  " t o " machine code  time  equipment  put  are  d o e s , and  pieces  held  p a s s a g e of  operands  of  block  ADVANCE  the  subroutine  as  i s t o be  Hence  simulate  this  time  different  their  route,  distances  t r a n s p o r t a t i o n time by t i m e s of  pieces  along  i t .  Pieces #1,  #2  flowing This  equipment  t r a n s p o r t a t i o n equipment  is  size. have  97  t o be t a k e n is  i n t o account  accomplished  operands and  by  whose  according  matrix  values  to this  savevalues  varying  as  length.  ADVANCE  This  block  a r e p r e c a l c u l a t e d as q u o t i e n t s  "A"  of l e n g t h  speed:  MH$TIME(P1,1) = MH$LNGTH(P1,1)/MH$SPEED(P1,1) Separate  Segment  calculations  57  Note t h a t  and  lengths  From  Figure  6.10,  on  Twin  formula  with  of  "A"  ...TMM6 i n P a r t  mill are:  wait  operand  of  are  be  9  V$TMM1,  f o r the  c a n be c o n v e y e d f o r  and  calculated  The  performed  component  i t separates time while their  The r e a s o n  The  6.4.  times  is  piece  t h e time  i t s processing according  transportation formula  V$TMM2,  length  are i n i t i a l i s e d  easy t o see t h a t  at Roll  belts+17  to  equipment has ADVANCE  ...V$TMM6.  The  by v a r i a b l e s o f TMM1,  TMM2,  5.2.1.  important  for  can  is  these  and s p e e d  rolls+5  i n Appendix  t i m e c a l c u l a t e d by t h i s  i s the unscrambler.  takes  it  (TEL-PL)/TES.  calculations  An  14  pieces  out  length  transportation  arriving  Saw,  i t s conveying  actual  only  i s that  factor affecting  start  blocks  are  2.1 and summarized  between a p i e c e  with  57)  o f t h e t r a n s p o r t a t i o n equipment  passing  the  carries  the t r a n s p o r t a t i o n equipment.  i n Part  third  length.  along  data  t h e model The  5.3,  items of t r a n s p o r t a t i o n equipment.  speed  for  Part 2,  there  c a l c u l a t i o n s of time data  various  it  in  f o r a l l (P1 = 1,  combinations. chains=36  #1,  pieces  of t r a n s p o r t a t i o n e q u i p m e n t  Major c h a r a c t e r i s t i c s  of i t s operation  one by one; i t has a l i m i t e d  pieces  turn u n t i l  flow  through  i t ; and p i e c e s  an empty u n s c r a m b l e r  i n the  capacity; have  to  unit arrives at  98  r-  PL TEL TES  - piece length - t r a n s p o r t a t i o n equipment - t r a n s p o r t a t i o n equipment  Figure  the  6.10.  Transportation  bottom p o s i t i o n . As  an  one  operation  which d e s c r i b e s dropsorter"  piece  Twin  unscrambler  causing piece  serves pieces  flows  facilities In  Part  the  flow  Saw.  the  Chain  seen  length  accordingly.  sequences  i n t h e segment  The  first  blocks.  (lowest)  simulating of Part  the  8.9  within  (topmost) the usual  The l a s t  facility  one  one, whereas t h e f i r s t  by  letting  pieces  storage  that  i n one by one  is  the  related  and a  sum o f t h e two  ADVANCE  definitions,  a s t h e maximum  ensures  Passage of time w h i l e  unscrambler  other  and l a s t  by f a c i l i t i e s  and t h e one s t o r a g e  among  blocks.  the unscrambler  number o f p i e c e s  that  the  c a n convey a t a time.  conjunction  problem a r i s e s to  block  t o queue f o r p r o c e s s i n g .  capacities are defined  In  by p i e c e  between Combined M a c h i n e #1 and " v i a  a s an e n t r a n c e  related  unscrambler  be  unscrambler  through  3,  i s affected  the  units are represented  leave  facility  of  can  ENTER and LEAVE s t o r a g e pieces  time  The model h a s t o o p e r a t e  example,  unscrambler  length speed  with  when p i e c e s  2 or R o l l  4.  required direction  transportation  flowing  In the r e a l  equipment  through Chain  another  1 can e i t h e r  go  s y s t e m , movement o f lumber i n  i s accomplished  by  skid  transfers  that  99  either  raise  chain  under  chain  or  to  roll  roll  level.  function  area  This causes  lumber  1 and R o l l to  4.  related  variable  or  calculate either  TMC1W  the conveying  perpendicular  directions. same  either  to length  except  that  definitions  of these  governing  important  mill  transportation  dynamics device  enough f o r t h e  transportation large can  time  is a  Unfortunately  COM  This 1,  These  piece  i s why t h e  can  two  is  both  be t h e  variables  transported  to  (TMC1W) o r l o n g i t u d i o n a l (TMC1L)  they  exactly  c a l c u l a t e the conveying of Chain  4 and R o l l  the  time o f 6.  The  a r i t h m e t i c v a r i a b l e s a r e i n P a r t 5.2.2  the model. Another  not  four  the l a s t  named COM 1 a s  The v a r i a b l e s o f TMC2W a n d TMC2L have  meaning  moves  alternating  The c o n v e y i n g  to  a  COM2 a s common t r a n s p o r t a t i o n a r e a s  of  This  facility  TMC1L.  t i m e when  o f lumber  direction.  "A" o p e r a n d o f Advance b l o c k  in either  can not occupy  cover.  depend on r o u t e  o r lower t h e  move  i f a piece  by a s i n g l e s e r v e r  of C h a i n  distance  of  to  1 f o r a c e r t a i n time p e r i o d .  of speed and d i s t a n c e  and  of the r o l l  lumber  Note t h a t  the succeeding  i s simulated  common  above t h e l e v e l  direction.  of Chain  movement  speed  roll  direction,  section  a  the chain  degree  cause  i scapacity. i s so h i g h  arriving  equipment  the operation  that  When t h e  that  characteristic  occupancy  the remaining  lumber,  i t denies  serve  as surge a r e a s ,  of t h e p r e c e d i n g  mill  of  a  capacity i s  entry.  Thus  affect  to a  components  and  congestion.  Capacities  of  belts  measures, because t h e i r difference  t r a n s p o r t a t i o n equipment  between  and  occupancy  belt  or r o l l  rolls  a r e d e t e r m i n e d by l i n e a r  then  c a n be c a l c u l a t e d a s t h e  capacity  a n d t h e sum o f lumber  100  lengths  occupying  hand,  capacities  transverse or or  the t r a n s p o r t a t i o n equipment. of  chains  d i r e c t i o n s , are determined  more  are allowed  t o be c o n v e y e d  t r a n s p o r t i n g cants  determined  in linear  moving  lumber  capacities Chains  section  maximum  Cross  Chains  s i d e by s i d e , have c a p a c i t i e s  measure.  Chains  lumbers  then  chain  capacity  #16  unscramblers,  and  #17  also  have  fact  that  on t h e t o p o f e a c h  other  In view o f  occupancy  capacities  by s t o r a g e As  can  definition  be  seen  of  can  the  i n square  be  measures.  calculated  as  and t h e sum o f lumber  refused  to  keep u p - t o - d a t e  to  the cross  o f lumber  capacities  the  Fortran  v e r s i o n o f SAWSIM  dialect,  overcome t h i s  will  can not p r o v i d e problem  length,  be  the  To  width,  lumber  dynamic  model  or must  calculate  and t h i c k n e s s must be known.  according  such  allowed  the simulator  of p r o c e s s i n g ,  modified  are  d i s c u s s i o n , t o make a  of a v a i l a b l e c a p a c i t i e s .  d i m e n s i o n s o f p i e c e s , a t any s t a g e current  equipment  3 of the model.  a transportation unit  records  available  i n Part  from t h e f o r e g o i n g  whether o r n o t a p i e c e enter  transportation  cards  decision  To  measures  areas.  The  these  in  one l a y e r o f lumber  have c a p a c i t i e s d e f i n e d  between  other  movement  on t h e c h a i n .  after  transfer  these  capacity  difference  given  in linear  the  by e i t h e r l i n e a r  Similarly,  trimmers  #7,8,...,15  chain  only  measures.  to  given  (more l a y e r s ) ,  The  lumber  s q u a r e m e a s u r e s d e p e n d i n g on whether o n l y  #1,2,...,6  The  providing  On  size  to  the  IBM  information.  generates  these  lumber d i m e n s i o n s a s f o l l o w s . The sawlog  length  o f any p i e c e  i t i s produced  from.  o f lumber  i s equal  t o the l e n g t h of  101  Thicknesses assigned 4.1.2  are  t o Parameter  are  9 by t h e  of  market  function  randomly a s s i g n e d  according  to the piece  cant/side  board(a),  cant  with  t h a t need  final  cross  Figure  6.11.  Method interval 8  and  named  are  THICK  t o Parameter  question.  A  piece  cant(b), center  pieces  always  in  section dimensions(d),  Part  is  calculation  Four d i f f e r e n t  opening  5.1).  random w i d t h  faces  to  way  t o Combined M a c h i n e  via  block  that  (6")  i s performed  As an example,  be  +  edged  #2 a r e a s s i g n e d  ASSIGN 8,$CANTW b e f o r e  from  lumber  (d)  (  sideboards  width  within  the  The l o w e r e n d p o i n t  the width of the s m a l l e s t wane  (2*1")=8".  by f l o a t i n g - p o i n t  see Part  either  originating  ways o f a s s i g n i n g p i e c e  on t h e a s s u m p t i o n  itself  can  ways,  F i g u r e 6.11.  (cj  (b)  (a) a s s i g n s  i s based  8 i n four  f u r t h e r breakdown(c), or already  o f [ 8 , d ] , where d i s l o g d i a m e t e r .  sideboard  (Part  in  only  (a)  of  function  of the model. Widths  a  a  v a r i a b l e CANTW  8.6 where p i e c e s cant  on t h e i r  or sideboard  e n t e r i n g Chain  The  4.  widths  1 02  Method cant  (b) s i m p l y  width.  copies  As an example  the l o g diameter  these has  (c) assigns cant  p i e c e s can only  only  two d i s c r e t e  Method Functions  pieces  10  which  However,  equipment  in  consideration  order  is full  counterfeit the  stops  simple  of  if  for  this  unit  facility  "entrance" block. by t h i s does  ASSIGN  c a p a c i t i e s of  by  the  flow  a  The p r o b l e m  b l o c k s , ENTER  or  Consequently,  the  i s that  SEIZE,  interruption  not  exercise i t s effect. cause of  and t h e  are  always  the  full"  even case  of the s t o r a g e or having  preceding  flow  using  of t h e s a n d w i c h  front  and  accurate  for f a c i l i t i e s  block  in  GPSS  space or a  sufficiently  When t h e " c a p a c i t y  waiting  model.  accurately,  i f a storage  transactions  the l a s t  m a c h i n e r y breakdown, a s a n o t h e r  block  limited  account  flow  storages,  are  via  i s not s u f f i c i e n t .  i s not  is full.  codes.  addressed  The  piece  behaviour.  t o r e l e a s e or l e a v e  transactions  reaction"  into  simulate  real m i l l  occurs,  affected  how  capacity limits  although  on market  8.13).  SEIZE-ADVANCE-RELEASE s a n d w i c h  the succeeding  preceding  a r e taken  4.1.1).  As an example, see  Trimmer.  described  transaction  ENTER-ADVANCE-LEAVE allowed  to  Since  function#3  (Part  are i n d i r e c t l y  (Part  to  of these  automatically facility  task.  paragraphs  transportation  8 o r 12.  a market code.  #1  width.  8 o r 12 i n c h e s w i d e ,  widths,  carries  8,FN*10 p e r f o r m s t h i s  piece  lumber w i d t h s d e p e n d i n g  from Combined E d g e r  Previous  t h i c k n e s s as  p o i n t s of v a l u e s :  a s s i g n i n g these  Parameter  (Part 8.7).  be e i t h e r  (d) a s s i g n s  8 as  see the b l o c k of  ASSIGN 8,&VALUE Method  t o Parameter  so  unit  the  i s not  called  For s i m i l a r stopping  left  "chain reasons,  piece  flow,  103  should  a l s o be  The sawmill or of  considered.  term  "chain  when f u l l  reaction"  c a p a c i t y o r breakdown  t r a n s p o r t a t i o n equipment preceding  model  must  a machine into not  u n i t s of m i l l have  there  simulate  this  t h a t does not a l l o w unless  stopping  the  dynamic  pieces  pieces  to  objects, transportation  are three  p o s s i b l e cases  t o be  leave  can  enter of  t r a n s p o r t a t i o n equipment  -  machine  - t r a n s p o r t a t i o n equipment.  t h a t machine  - machine  equipment  ...ENTER(TE1),  permutation  i s always  s i m u l a t i o n of " c h a i n  sequence  ,ENTER(TE2),LEAVE(TE1), f o r the f i r s t  case,  for  the second case.  sequences  have  the  GPSS b l o c k  glance  machines.)  ensured  by  ,LEAVE(TE2),...,  ,RELEASE(MAC) The a b b r e v i a t i o n s  meaning  as  i n the TE1  follows:  # 1 , T E 2 - T r a n s p o r t a t i o n Equipment  Equipment  TE - T r a n s p o r t a t i o n E q u i p m e n t , at f i r s t  because  and  block  Transportation  between  r e a c t i o n " i s simply  ,SEIZE(MAC),LEAVE(TE),  block  i s impossible  installed  ...ENTER(TE), sequence  and  considered:  •  The  MAC  - Machine.  Despite  the  seem t o be  strange,  sequence e n s u r e s t h a t a p i e c e  i s allowed  to  of machinery  i f , and  to  receive  is  used t o l e t p i e c e s  only  In t h e t h i r d go  i f , the succeeding  case,  a TEST b l o c k  f r o m t h e machine  unit  the  leave is  in refusal  i f and o n l y  #2, fact  the sequence might  i t .  two  equipment  - t r a n s p o r t a t i o n equipment,  transportation  unit  then  t r a n s p o r t a t i o n equipment  (Notice  that  up and  in a  machine  •  • machine  above  of a downstream  Among t h e p o s s i b l e p e r m u t a t i o n s  necessarily distinct  block  To  o r t r a n s p o r t a t i o n equipment unit.  t o t h e phenomenon  causes f i l l i n g  flow.  a mechanism  a succeeding  machine,  refers  if  a  ready mode, three  104  coditions  are  available,  the remainder c a p a c i t y  large in  met  simultaneously:  o f t r a n s p o r t a t i o n equipment i s  enough t o r e c e i v e t h e p i e c e ( s ) , and no p i e c e s an  imaginary  equipment. whose  queue  between  The a c t u a l t e s t  value  Boolean  is  1  are  representing  in  defined  i n Part  machine o p e r a t i o n ,  statistics  machine was  about  going  to  Chain  #8  two l i n e s  statistical until  the  decision after  (Trimmer  lumber in  are true.  transportation  Among  there  a r e two a d d i t i o n a l b l o c k s ,  the length  the block  statements  two b l o c k s i s  of time d u r i n g  which  the  overridden  case pieces  Twin Saw v i a t h e d r o p s o r t e r ,  have  line  routes  leaves real  Since,  the  mill  the  to  #9  when  one  trimmer,  50-50%  (Trimmer  line  simulates  the  above  piece,  via  an u n c o n d i t i o n a l  labeled  SKIP  ( P a r t 8.15).  #2).  flow route  i s down.  Part  of  multiplication they  TRANSFER decision In t h i s  in operation.  TRANSFER b l o c k ,  This  at  r u l e of route  a t a machine has been  i n t o one b e f o r e  through  TRANSFER b l o c k s i n  probabilities  o f t h e two t r i m m e r s  piece/transaction  take,  model  and  However, t h i s  t o the trimmer  Whenever an o p e r a t i o n  the  t o the  depends on w o r k l o a d s a t b i n s o r t e r s  the a p p l i e d  go o n l y  transactions  two  #1) o r C h a i n  mode.  are approximations.  erroneous  variables  5.3.  a r e c h o s e n a t random by u s i n g  transfer  trimmers,  blocks  a l l  The p u r p o s e of t h e s e  the  E d g e r and t o t h e T r i m m e r s ,  These  transportation  conditions  with  waiting  blocked.  Pieces  either  and  are  o u t on B o o l e a n  a l l three  conjunction  QUEUE and DEPART t o m e n t i o n . to c o l l e c t  machine  i s carried  whenever  variables  equipment  is  t r a n s p o r t a t i o n equipment i s  enter  finished,  skips  the by  the  to the block  model  prevents  assembling the  t h e SPLIT b l o c k  and  the  1 05  right  number o f t r a n s a c t i o n s  consider  the f o l l o w i n g  As  was  general  discussed  going two  to  a(i,j) the  rows  earlier,  information the  word  consider does per  DIA  n o t mean t h a t  that  that  the  edging  GPSS,  "offspring"  sense t h a t  for  I t i s very  of F i g u r e  matrices.  (Since  the l a s t  transmitting  important  6.5.  other  is valid i f  to  emphasize  To see why,  Its  f o r each of the 3 p i e c e s  a(5,13)=4  l e t us element  (a(2,5)=3) 4 p i e c e s  go t o machine  TRM.  It  means  l e a v i n g Combined M a c h i n e  a piece  i s after  blocks  which  blocks  in  block  feature  #2 i n  of  and takes  To a v o i d with  order  place  in  the Since  p o i n t of  as o f t e n as  according  this,  a  to the  a cluster  of  the purpose of assembling  machine.  There  are  t h e program t o assemble p i e c e s t h e ASSEMBLE  an  block i s  sawing  from t h e e x e c u t i o n  introduced  before  bring  c u t i n t o more t h a n one p i e c e .  a particular in  can  Hence, t h i s  i t , t h e model would o p e r a t e  is  Just  which  the model.  multiplication.  leave  from one l o g .  into  machine o p e r a t i o n s  piece  faulty  SPLIT  of the model,  above  ASSEMBLE  the  i s being  enters  ASSEMBLE  is  the m u l t i p l i c a t i o n  transaction  blocks  used  between  number o f p i e c e s  number, t h e above d e f i n i t i o n  transaction  SPLIT b l o c k  pieces  are  number o f p i e c e s  it  used t o s i m u l a t e  view,  this,  mode (CE2) i s 4.  In  the  the t o t a l  DIA  from t h e i - t h one.  i s 3*4=12 p i e c e s  total  by  i n t h e above d e f i n i t i o n .  t h e DIA m a t r i x  piece,  transmission  i s accomplished  i<(max(i)-2)).  "total"  the data  represents  matrix  than p i e c e  subscript  the  element  j - t h machine  of  To u n d e r s t a n d  example.  SAWSIM and t h e dynamic model Its  i s propagated.  set, a  separate  originating  group  of  TEST  c o n d i t i o n a l t r a n s f e r mode, sends t r a n s a c t i o n s t o t h e  106  one  of  t h e ASSEMBLE b l o c k s  machine  whose  the  first  the  same  arrived,  number  machine a l s o they  are  transactions  t o be  this  Parameter  After  having  block  to t r i g g e r  its  is  used  until  from  as  into  of p i e c e s  2.  equivalent At  the  "A"  of  the  t h e ASSEMBLE b l o c k  other  transactions  from  t r a n s a c t i o n s have  model  and  t o SPLIT b l o c k .  i s assigned  only The  one  number  to Parameter  5,  of  hence  o p e r a n d of t h e ASSEMBLE b l o c k s .  one,  the  i t s propagation  t h e m a c h i n e of n e x t  the  Once a l l o t h e r  flow  assembled  assembled  number  enter.  removed  continues  is  i s i n Parameter  t r a n s a c t i o n i s delayed  transaction  right  which,  i s sent  t r a n s a c t i o n goes  activity  (Part  to block  labeled  o p e r a t i o n and  its  to  8.15).  preceding  SPLIT  Then  SLCT t o  the  select  transportation  equipment. Summarizing, of  as  a  t h e whole p r o c e s s  series  of  transportation/machine piece  flow  Each c y c l e of  is  s i m u l a t e s one  t h e whole p r o c e s s . segment  The  2.  t r a n s p o r t a t i o n equipment  flow  originating program  itself  operation. suggests,  As  (Part  the  end  group  operation  unit  consists  of  and  8.14).  i t ends a t t h e  does not  cycles.  segment,  s i m u l a t i o n of a p a r t i c u l a r  from  of  the  8.15),  3. m a c h i n e o p e r a t i o n segment,  The  thought  operation,  a series  s i m u l a t i o n of e a c h c y c l e  (Part  segment  by  be  Accordingly,  transportation/machine  split  assemble  ...,etc.  accomplished  1.  4.  s a w m i l l i n g can  transportation/machine  operation,  simulation  of  trimmers.  with of  the  report  t h e computer p r o g r a m ends w i t h  s a w l o g and  the  However, t h e simulation statements  of  pieces  computer trimmer  in Table  i t s report writer  6.1  (Part  107  10).  These r e p o r t  about  relevant  statistics  • absolute blocked  statements ensure  and  of m i l l  relative  a  "tailor  made"  summary  behaviour:  (%) t i m e  statistics  of i d l e ,  busy,  and down s t a t e s o f m a c h i n e s ,  • bar c h a r t s • piece  o f t h e above u t i l i z a t i o n  counts  of  both  statistics,  machines  and  transportation  equipment, • maximum  content  and a v e r a g e u t i l i z a t i o n  of t r a n s p o r t a t i o n  equipment, • waiting  statistics  at various  « number o f boom l o g s p r o c e s s e d All Chapter  these  outputs  8 d e a l i n g with  will  be  the r e s u l t s  piece during  flow  points,  simulation e t c .  displayed  and  of s i m u l a t i o n  discussed runs.  in  1 08  7.  Validation problems showing to,  of  not  i s one  of  computer  that  one  MODEL VALIDATION  the  most  simulation.  t h e model m i m i c s t h e  can  not  trust  the  make d e c i s i o n s , s a y ,  on  and  Important,  real  results  because  s y s t e m as  produced  by  difficult  i t is  without supposed  t h e model and  t h e c o n s t r u c t i o n of a s a w m i l l  millions  of  dollars.  validating  a s i m u l a t i o n model  theoretical,  important  Validation  statistical,  is  difficult,  " . . . i n v o l v e s a host  and  of  can  worth because  practical,  even p h i l o s o p h i c a l c o m p l e x i t i e s "  (68). In t h e  stage  validity?  of v a l i d a t i o n ,  What  is  a  validating  a  simulation  theory,  found.  i n s t a n c e : "The  For  of  the e x t e n t  "A  valid  the of  model  simulation  mean?  In  the  answers  to  these  to which  validity  u n d e r l y i n g phenomena"  additional  questions.  behave  (68).  "To  "similar"  Answers analyst  to  to the  system  these  questions  to the  field  of  What  does  easily  be  o b j e c t i v e s " (66).  i n a manner  verify  similar  or v a l i d a t e  true"  (69). and  too  general  we  say  t h a t t h e model  i t mimics? -  is  computer  can  are  When can  What  of  questions  i t s design  should  answers  model?  literature  model means t o p r o v e t h e model t o be these  arise.  of a s i m u l a t i o n i s a measure  i t satisfies  s i m u l a t i o n model  However,  is  valid  many q u e s t i o n s  Can  i f they  philosophy,  but  we  they  recognize  exist the  any  kind  generate behaviour "truth"?  at a l l - take most  to  the  important  109  question  is  still  unanswered.  How  t o go a b o u t  validating a  model? In g e n e r a l , the is  first  step  internally  This  stage  the task  produced  of  i s a two-step  t h e a n a l y s t h a s t o make s u r e  by  i s u s u a l l y done  results  a model  correct in a logical  In t h e s e c o n d interest,  validating  the  represents  a  conjunction  with  is  the  by  real  check  simulation  comparing  non-existing the second  step  if  In  "... t h e model sense."  the  (68)  results  of  model, a r e b e l i e v a b l e .  model  Since  mill  that  and programming  to  world.  process.  outputs  with  known  t h e model o f t h i s  thesis  redesign,  difficulties  in  arise.  "When a model i s i n t e n d e d t o s i m u l a t e a new o r proposed system f o r which no a c t u a l data are available, there i s no good way t o v e r i f y t h a t the model, in fact, represents the system. Under these circumstances, there is little a l t e r n a t i v e b u t t o t e s t t h e model t h o r o u g h l y f o r l o g i c a l o r p r o g r a m i n g e r r o r s and t o be a l e r t f o r any d i s c r e p a n c i e s or u n u s u a l c h a r a c t e r i s t i c s i n the results obtained from the model", Meier (68) . How  then  c a n t h e model used  Referring (66),  the  model  objectives. validating The lumber  flow  a  Gnugnoli  t o be c h e c k e d will  t h e s i s be v a l i d a t e d ? definition  of  i f i t satisfies  be  the  validity i t s design  starting  point  of  FLOWSIM. basic  o b j e c t i v e of c o n s t r u c t i n g FLOWSIM i s t o p r e d i c t  production Thus,  large  by  operate  as  a  function  the accuracy  degree  simulation.  validated flow  has  and  This d e f i n i t i o n  throughput. to  to Maisel  in this  log  of production  on t h e a c c u r a c y  Therefore,  testing  of  estimation  and l o g depends  o f l o g breakdown a n d p i e c e  t h e model of  i f logic  breakdown  of both  a c c u r a t e l y enough t o f u l f i l l  this  thesis  can  be  l o g breakdown and p i e c e the design  objectives.  1 10  As log  described earlier,  breakdown  logic.  FLOWSIM s i m u l a t e s of  this  study  7.1.  Based on t h e SAWSIM s a w i n g  piece  flow.  flow  validation  is  i n use f o r more  reflected  research  sawmills.  coastal  program  o f t h e above  SAWSIM and t a k e s model  SAWSIM does Therefore, machine  on  a  Its  multi-million  lumber  L t d . , used  f o r design  recovery in  i t to  improve  of new c o a s t a l m i l l s .  i t for set-table  L t d . , has  f o r granted.  not inputs  used  generation.  the software f o r  mean of  of  that  Plotted  determine  SAWSIM and  research  transmitted  be  used  corresponding  to  log  shape the m i l l  to test  outputs if  thesis  data  i t cannot  f o r and d i s c u s s e d w i t h  markets.  this  trusts to the  However, n o t i c e t h a t c o r r e c t n e s s o f  o p t i o n of SAWSIM was used  to  facts,  the accuracy  specification,  displayed  checked  years.  design p r o j e c t s .  dynamic  all  and  (International)  In t h e v i e w  an  SAWSIM  Bloedel  Z e l l e r b a c h Canada L t d . , u s e d  sawmill  seven  aimed a t i m p r o v i n g  operations  Caroll-Hatch  in  employed  MacMillan  mill  than  by t h e names o f c o m p a n i e s a p p l y i n g i t .  W e y e r h a e u s e r Company has  Crown  t h e model  LOG BREAKDOWN VALIDATION  reputation  its  Accordingly, validating  validation  SAWSIM h a s been  dollar  information,  i n c l u d e s two s t a g e s :  • Log breakdown • Piece  t h e dynamic model u s e s SAWSIM as i t s  the  of logs  each  lumber  sizes,  characteristics  were  management. sawing  SAWSIM were  incorrectly.  were sawn  SAWPLOT,  patterns  for  examined and as  they  were  111  intended.  7.2.  P I E C E FLOW VALIDATION  The  validity  of p i e c e  1.  FLOWSIM s i m u l a t e s  flow  simulation w i l l  piece  flow  according  be a c c e p t e d i f : t o SAWSIM  sawing  instructions, i.e., 1.1. correspond  if  the  number o f p i e c e s p r o d u c e d  t o t h e number o f p i e c e s  1.2.  i f the machines used  from a g i v e n l o g  c u t by SAWSIM ; t o process  a l o g correspond  to  m a c h i n e s u s e d by SAWSIM t o "saw" t h e same l o g ; 1.3. the  propagation  number o f " o f f s p r i n g " 1.4.  to  i f the piece  2.  The  correct, cases  times time  sequence  the board  Pieces  flow  between m a c h i n e s 4.  The  to process  pieces  manufacturing  logic  through  o f t h e model p r e v e n t s  from t h i s  the r i g h t  being  sizes,  taken  into  account  i s calculated, are satisfactory;  6. I n t e r a c t i o n o f m i l l  machinery  units  breakdown  of  a  to  equipment  when t r a n s p o r t a t i o n  are correct;  refers  p r e c e d e d by  transportation  statistics  reaction"  absurd  log;  5. M a c h i n e u t i l i z a t i o n  i . e . , the chain  is  d e s t i n a t i o n and t i m e ;  equipment c a p a c i t y u t i l i z a t i o n  model,  correspond  operations  a l o g on t h e h e a d r i g  originating  i n both  piece  of  flow  such as p r o c e s s i n g  3.  needed  c a l c u l a t e d by SAWSIM;  i . e . , the piece  manufacturing  to  p i e c e s c a l c u l a t e d by SAWSIM ;  i f time p e r i o d s  processing  a t machines corresponds  reaction i s simulated.  the  phenomenon  in  a  is  built  i n the  (The term sawmill  "chain  when  the  downstream m a c h i n e o r t r a n s p o r t a t i o n equipment  11 2  causes  filling  To  test  actions  up and s t o p s p r e c e d i n g u n i t s  model v a l i d i t y  were  taken. out  deterministic  the sense  in  to  known v a l u e s d e t e r m i n e d are  excluded.  relevant are the  event  short total  tedious  The  verify  history  that  were  that  check  piece  aspects,  a single  (Figure  7.1).  model.  hence  following  The  test  runs  stochastic  monitored  in  the  out i n d e t a i l .  only  p r o c e s s a r e checked  the  are  random s o u r c e s a r e r e p l a c e d by  i s printed  i n t h e sense  flow.)  m o n i t o r e d and s h o r t  the  i n advance,  runs  n a t u r e of t h i s  To  of t h e above a s p e c t s  Deterministic,  r u n s were c a r r i e d  of m i l l  elements sense  that  Finally,  runs  a few b u t i m p o r t a n t e v e n t s o f  because  o f t h e time c o n s u m i n g  and  checking procedure.  f l o w c o r r e c t n e s s c o r r e s p o n d i n g t o t h e above  l o g was "sawn", p r i n t e d The  same  log  was  and p l o t t e d  processed  by  SAWSIM  t h r o u g h FLOWSIM  (Figure 7.2). The checked pieces  number  of p i e c e s produced  by a d d i n g up t h e p i e c e leave the m i l l  paragraphs numbers  reference  i n square  (Figure will  brackets.  from  Throughout  made  and s i x a t Trimmer2,  SAWSIM p i e c e c o u n t  o f 8.  machines  propagation  [1.3],  used based  to  the  The sum o f trimmer  8, two a t T r i m m e r l  The  log  [1.1] can  c o u n t s o f t h e two t r i m m e r s  7.2). be  the  which  the  be  where  following  above a s p e c t s by piece counts  is  corresponds to the  t o p r o c e s s the l o g [1.2] and t h e p i e c e on SAWSIM  output,  are  summarized  in  T a b l e 7.1. The output  machines  by t h e column  indicate  the  processing  t h e l o g c a n be c h e c k e d  of " p i e c e c o u n t " .  machines used  Non-zero  t o process the l o g .  i n FLOWSIM  piece These  counts non-zero  113  <% <x  LOC SAVING IDENT PATTERN  —  OFFSET  —  vcl  01* IN  tEN TAPER --SWEEP-- CUFT PCS FBH FB«V CHIP LUMBER BrPRD COST FT IN/FT E06E CYL ACTUAL LBR LBR CUFT CUFT * $ •  CROSS M f CUNIT  <%>  F3 /1 FM03 HEDBCB1 HEDBGB1 HB9-CE1 HM-CG1 M**~eNG HM-TW HBB-CE2 HB8-C02 MR8-0NG HRB-TtM CE1-TM CG1-TMN C61-0TW CCi-EDC CGi-'R 1.OOO 0.0 It) CO 31 10 O 123 0.0 0 0 •! I • 155 B.2T 10 5 1M.4S B BO 0 0 14*05 3*4 9 <% PASSES JO <% SECONDS as  *% t  <X CE2-TRK C62-THN CC2-DTW CC2-EDG C63-TMI 0N6-TMN ONB-OT* 0N6-EDG ONG-TRH TMN-TMD TBN-EDC TtM-TBM OTW-TWD DTW-ED6 DTW-TB *t PASSES 2 1 9 <* SECONDS 4 B. 10  <X  *  <% TH0-T01 TWD-EDG TMD-TBM T01-EDG TD1-TM EDO-TRM CHIPPER <X PASSES 1 2 <% SECONDS 2. <X  *  SAMSIK PLOT F3 / 1 FM03  3X09 20  3X09 20  3X0B 20  3X09 20  ONE INCH  Figure  3X09 20  7.1. SAWSIM o u t p u t  to validate  FLOWSIM  results  SIMULATION RESULTS OF MACMILLAN BLOEDEL WR3 SAWMILL DESIGN. 08:39 P.M. Sawmill  o p e r a t i o n was s i m u l a t e d f o r  MAR. 04, 1984  431 sec.  MACHINE UTILIZATIONS AND PIECE COUNTS. Name HRG9 HRG8 CMB 1 CMB2 GANG TWIN EDGER TRMR1 TRMR2  Idle T ime % 431.0 405.0 431 .0 385.0 431.0 431.0 423.0 427.0 419.0  TRANSPORTATION  100.0 93.9 100.0 89.3 100.0 100.0 98. 1 99.0 97.2  EQUIPMENT  Busy T Ime 0.0 25.9 0.0 45.9 0.0 0.0 7.9 3.9 11.9  %  0.0 6.0 0.0 10.6 0.0 0.0 1.8 0.9 2.7  Blocked T ime X 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  Down Time  0.0 0.0  o.b  0.0 0.0 0.0 0.0 0.0 0.0  0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  P i e c e Count X 0..0 0 .0 0 0 0 .0 0 .0 0 .0 0 0 0. 0 0..0  O 1  o  3 O 0 1 2 6  PIECE COUNTS.  TRANSPORTATION PIECE COUNTS:  EQUIPMENTS:  BLT01 0  BLT02 8  BLT03 0  BLT04 1  BLT05 0  CHN01 0  CHN02 0  CHN03 0  CHN04 3  CHNOB 3  TRANSPORTATION PIECE COUNTS:  EQUIPMENTS:  CHN06 0  CHN07 0  CHN08 3  CHN09 6  CHN10 0  CHN11 0  CHN12 1  CHN13 0  CHN14 0  CHN1B 0  TRANSPORTATION PIECE COUNTS:  EQUIPMENTS:  CHN16 2  CHN17 6  R0L01 0  ROL02 3  R0L03 0  ROL04 0  ROLOS 0  ROLOS 0  R0L07 8  R0LO8 0  TRANSPORTATION PIECE COUNTS:  EQUIPMENTS:  R0L09 0  R0L10 0  R0L11 1  R0L12 0  R0L13 1  ROL 14 0  UNSC1 3  UNSC2 6  115 Table  7.1.  Piece propagation the l o g  FLOWSIM Number of arriving leaving p i e c e s  M a c h i n e s used to process the l o g Headrig  a t machines used  8'  to  process  SAWSIM piece counts* "from"  "to"  1  3  HR8 HR8  -> ->  CE2 CG2  = 2 = 1  Comb.mach#2  3  8  CE2 CG2 CG2  -> -> ->  TRM EDG TRM  = 2 = 1 = 5  Edger  1  1  EDG  .->  TRM  = 1  Trimmers  8  8  * N o t e : the number of p i e c e s p r o c e s s e d a t a machine i s t h e sum of numbers a t t h e end of t h o s e l i n e s i n w h i c h t h e " t o " m a c h i n e code i s t h e machine i n q u e s t i o n ; t h e number of p i e c e s l e a v i n g a machine i s t h e sum of numbers a t t h e end of t h o s e l i n e s i n w h i c h t h e " f r o m " m a c h i n e code i s the machine i n q u e s t i o n . entries 1  and  also give  the  number of a r r i v i n g  8 corresponding  and  Trimmers,  of  pieces  to Headrig  respectively.  leaving  transportation  machines  equipment  8',  Piece can  piece  p i e c e s which are  Combined machine #2,  propagation, best  be  i . e . , the  checked  counts a f t e r  are  respectively,  FLOWSIM  accomplished  propagation The  the  through  the  t i m e s e q u e n c e of right  interactive  through  instructions  sideboard the  of  debugging used  operations  or mill.  facilities  to track  a piece This  of  3,  pieces,  8  The  and  1,  piece  process  [ 2 ] , and  a  log  i f pieces  flow  [3] were  of  the  SAWSIM.  needed t o  t r a n s p o r t a t i o n equipment  SYSTEM" command was cant,  to the  c o r r e c t n e s s of machine t i m e s  [1.4],  the  according  that  number  the machines.  Roll#13  3,  Edger  by  p i e c e c o u n t s of Chain#4, R o l l # 7 and indicating  1,  checked  GPSS/H.  The  by  "TRAP  be  it  log,  center  lumber, w h i l e  they  were  flowing  command  tracks  transactions,  116  representing step  pieces,  f a s h i o n , by  times. could  In be  through  stopping  this  and  displayed  and c h e c k e d .  Appendix  7.1.  run  output  file  edited  easily  be m o n i t o r e d  Figure  7.3  at  discrete  whole l o g m a n u f a c t u r i n g  The o u t p u t  and  together.  the  movement  transactions  i n a reformatted  was  show  the  i n a d e t a i l e d s t e p by  of  of t h i s  interest  Thus,  way  i n the  events belonging  correspondence  that  what  output  t o one t r a n s a c t i o n were  are  piece  can  transaction.  transactions  pieces  be  run i s i n  the  the corresponding  between  process  the i n t e r a c t i v e  t h e movement o f a p a r t i c u l a r  by o b s e r v i n g  summarizes  sense  event  could  interactive  T h i s appendix a c t u a l l y presents  grouped  To  their  mannner  monitored,  the system  and  represented  pieces by what  transact ions. To  monitor  piece  movement  interactive  debugging  information:  the simulation  Simulation Block the  clock  time  number i n d i r e c t l y mill.  This  number t e l l s program.  The  output  tells tells  the  time  7.1) a machine t i m e  event  happens.  the l o c a t i o n of the i s indirect,  mill  (Figure validity point  7.4). from  of view.  This  of  time c h a r t  machine  because  location  machinery  time  provides [1.4]  A t t h e same t i m e t h i s  block  be  or can  (Appendix constructed  t o check  and o p e r a t i o n  GPSS  machine  output  the b a s i s  block  the  GPSS  can  within  t h e GPSS  unit,  t o the  processing  piece  within  7.3 and t h e i n t e r a c t i v e  chart  p i e c e s of  when a p a r t i c u l a r  up i n t h e p r o g r a m . Figure  the  number.  then  on  space,  block  equipment, c o r r e s p o n d i n g  Based  and  two i m p o r t a n t and  transportation be l o o k e d  time  the  transaction  actual  in  provides  clock  information  only  both  model  s e q u e n c e [2]  c h a r t makes i t  easier  to  1 17  xact#14  Figure  7.3.  Correspondence  between t r a n s a c t i o n s  and  pieces.  118  survey are  t h e p i e c e movement  27-1=26 s e c o n d s  78=15  seconds  t o p r o c e s s t h e l o g on H e a d r i g  109-93=16 s e c o n d s  on Combined M a c h i n e  and  305-303=...=431-429=2  p i e c e s on T r i m m e r s . 7.1).  output  are  machine. number the  Notice that  total  of  means t h e t o t a l Figure of  needed  the t o t a l  breakdown  time  of p r i m a r y  w i t h those of  on  Headrig  8'  of  two  the  SAWSIM  process  a l l pieces at a  t i m e must be  divided  o f SAWSIM o u t p u t )  time  t o check  After  at  by  the  to get  manufacturing  i n e d g i n g mode i s  of  headrigs  always  that  having  finished  simulation  sideboards  t h e time  clock  and  sequence  primary l o g time  27,  t h e c e n t e r c a n t on  a t 63 and f i n i s h  a t 109 s i m u l a t i o n  A l l o f t h e p i e c e s c a n o n l y be p r o c e s s e d on Trimmers time. which  There  i s o n l y one p i e c e  needs e d g i n g .  out before the f i n a l  operation  shows  operation To  that  produced  Obviously, this  be c a r r i e d  the  the  breakdown.  be u s e d  Combined m a c h i n e #2 c a n s t a r t  cant  lumber  to  manufacturing  7.4 c a n a l s o  manufacturing  this  to process the f i n a l  For instance,  o p e r a t i o n [2] i s c o r r e c t .  time.  Edger;  ( i n "PASSES" l i n e s  The  cant  367-359=8 s e c o n d s t o  one s i d e b o a r d on Combined M a c h i n e #2  30/2=15 s e c o n d s .  Machine  m a c h i n e o p e r a t i o n t i m e d a t a o f SAWSIM  p r o c e s s i n g time per p i e c e .  time  78-63=93-  from c e n t e r c a n t on  time d a t a agree  times  pieces  edging  seconds  These  Consequently, of  8';  chart  to process the center  #2 i n gang e d g i n g mode;  the only p i e c e needing  (Figure  M a c h i n e t i m e s on t h i s  t o p r o c e s s t h e two s i d e b o a r d s on Combined  #2 i n e d g i n g mode;  process  i n time.  trimming.  simulation  from  edging This  center  o p e r a t i o n must  time  agrees  the  after  with  sequence the  of real  sequence. check  if  p i e c e s flow through  the r i g h t  transportation  119  27  LOG(XACT3)  HEADRIG 8'  SIDEBOARD SIDEBOARD CANT (XACT4) (XACT5) (XACT6) . 63 78 93  COMB.MACH. J2  -Af^i  I  t  109  .,  I  „i  EDGER  PFCC TO BE EDGED (XACT9) 359  429 431  TRIMMER 01 321 325 319 323 327  SIDEBOARD TO BE TRIMMED (XACT10) SIDEBOARD TO BE TRIMMED (XACT8) SIDEBOARD TO BE TRIMMED (XACT7)  TRIMMER «2  PFCC PFCC PFCC PFCC  TO TO TO TO  BE BE BE BE  TRIMMED TRIMMED TRIMMED TRIMMED  «U  I I I I I  W-  PFCC TO BE TRIMMED (XACT15)  (XACT11)»(XACT12) — (XACT13)*— (XACT14).-  SIMULATION TIME (SEC) 10 SEC  PFCC - PIECE FROM CENTER CANT  Figure 7 . 4 .  Time chart of log and piece processing  equipment [3] in both interactive  GPSSH  space  and  time,  let  up  movement can  the corresponding transactions. be  consider  run output again (Appendix 7.1).  pieces cut from the log above (Figure 7.1) looking  us  checked  by  finding  out  can  be  the  All of the checked by  The route of their the  correspondence  between GPSS blocks and transportation equipment (Appendix 7.1). As  an  example  Table 7.2 summarizes the movement of one of the  120  sideboards,  Table  represented  7.2. Movement o f s i d e b o a r d ( T r a n s a c t i o n #4) between H e a d r i g 8' and Combined M a c h i n e #2  Transportation equipment C h a i n #4 Com 2 C h a i n #5 Roll #2  Notice suggesting to  flow  that valid  Table piece  to  flow  through #4  Roll  (transaction  #2 #4)  7.4).  First,  equipment #5  time the  processing Finally,  are  see  transportation monitored  equipment  simulation  "satisfactory" not  i f piece  vs.  provide  sampled  10  same.  p e r i o d of time  Third,  the  starts  on  which  taken  utilization, run  was  sizes  from p r o b a b i l i t y  For  inch/second  Second, t h e  time  arrival  the when  Combined  are  sideboard #2  participating between  are correct. to calculate  satisfactory  carried  of  machine  i n t o account are  time  installed  out.  c o r r e c t must be e m p h a s i z e d piece  correct.  t r a n s p o r t a t i o n equipment  sizes,  needed  when l o g p r o c e s s i n g e n d s a t  to  a r e those  facts  the times  are  8' a n d Combined machine #2; hence t h e y  To  sizes,  are  important  Thus, t h e I8sec  corresponds  i n moving t h e s i d e b o a r d  does  simulation.  the  9 4 18 5  four  Chain#5 i s c o r r e c t .  and  Time n e e d e d t o flow through  36 40 58 63  displays  respectively.  1  Chain  leaving  Headrig  7.2  8' ( F i g u r e 7.4)  (Figure  27 36 40 58  transportation  (15 ),  needed t o flow  Headrig  S i m u l a t i o n time of Arrival Leave  t h e s p e e d and l e n g t h o f C h a i n  180"  time  GPSS b l o c k identification (COMB2+5) (COMB2+10) (COMB2+15) (LBL49+2)  through  instance, and  by t r a n s a c t i o n #4.  The  because  in i t s current  state.  distributions  by  [4]  a  word SAWSIM  Thus, t h e  FLOWSIM,  are  121  sometimes n o t a c c u r a t e . are  close  However,  t o the a c t u a l  For  piece  monitoring purposes  The 7.1),  second  under  the  transactions be  a t a p p r o p r i a t e p o i n t s of t h e model  to  transactions  sizes  comparison,  of  during was  log  arrival  possible  dynamic  controlled  "artificially".  9'  between  piece  [ 5 ] and  [ 6 ] were c h e c k e d  in  Figure  7.5.  By  9', breakdowns o f C h a i n #1 the  history  of  9' b e i n g  events  i n one o f  b u s y , b l o c k e d , and down) c a n be  FLOWSIM  results.  For  of m a n u f a c t u r i n g  simplicity,  only Headrig  t o breakdown and be i n a b l o c k e d  This " a r t i f i c i a l " machinery  by  l o g was made t o f l o w t h r o u g h t h e  machine,  (idle,  actual  statistics  p e r i o d s of Headrig  to  and c a u s e d  lists  machinery  control  was  carried  t i m i n g of e v e n t s , a c c o r d i n g t o the event machinery  F i g u r e 7.6 a l s o c o n t a i n s t h e t i m e  9'  state  out  breakdowns and l o g a r r i v a l  F i g u r e 7.6 by w h i c h t h e d e t e r m i n i s t i c  controlled.  might  c o n s i d e r e d by FLOWSIM.  are displayed  simulation  stochastical  predetermined in  displays  correspondence  7.3  to Headrig  states  and compared  the  replacing  (Appendix  SIZES",  utilization  of m i l l  results  the preceding Headrig  calculated  the  Table  run. A single  and i t s SAWSIM  four  and  Here a g a i n F i g u r e 7.3  and s i z e s  machine  becomes known and t h e t i m e its  of  GPSS o u t p u t  PIECE  parameters.  between u n i t s  controlling and  points,  and p i e c e s .  deterministic  mill  "CHECKING  on SAWPLOT o u t p u t  interaction  up b r e a k  by t h e "DISPLAY XACT=n" command.  appreciation  Correctness  a  title  convenient  based  by s e t t i n g  of the i n t e r a c t i v e  with t h e i r  helpful  For  part  averages  sizes.  t h e GPSS p r o c e s s o r was s t o p p e d t r a n s a c t i o n s were d i s p l a y e d  i n the long run t h e i r  by  with  schedule  breakdown was  intervals  of  the  122 Table  7.3.  Comparison of  Piece d e s c r i p t i o n  d1am inch  a c t u a l a n d FLOWSIM p i e c e  ( » ) A c t u a l s i z e of l e n g t h i t h l c k n . width ft inch inch  E q u i v a l e n t ( * ) S l z e s taken i n t o by FLOWSIM xactlon dlam l e n g t h t h l c k n . number inch ft Inch 11  21. 1  Log 18 S1deboard a f t e r headrig Sideboard a f t e r headrig Center cant Sideboard to be trimmed S1deboard to be trimmed P f c c to be edged P f c c to be trimmed P f c c t o be trimmed P f c c to be trimmed P f c c to be trimmed P f c c to be trimmed P f c c to be trimmed  sizes  15  XACT3 XACT4  15  XACT5  parameter 7  18  9  account width inch 8  21  12 13  21. 1  3  18 12  XACT6 XACT7  21  3  14 9  21 . 1  3  12  XACT8  21  3  9  21 . 1 21 . 1 21. 1 21? 1 21 < 1 21. 1 21. 1  3 3 3 3 3 3 3  9 9 9 9 9 9 9  XACT9 XACTIO XACT11 XACT12 XACT13 XACT14 XACT15  21 21 21 21 21 21 21  3 3 3 3 3 3 3  9 10 8 8 8 9 12  P f c c - P i e c e from c e n t e r cant (*)Note: Table contains only relevant s i z e s equipment occupancy.  four  states  (5+26+302), down  29,  states,  FLOWSIM  of  Headrig 20 a n d  100  (Figure  utilization  statistics.  Headrig  was  time  when The  Chain  #1  These  data  7.7)  and  idle,  correct  since  of  not to  between the  FLOWSIM.  the d e t a i l s  provide The o n l y  of  are  blocked,  valid  block  333 and  the data  Chain  end of  of  machine #1  and  state  and  cases  is  correspond.  of  convincing purpose  busy,  indicate  available again  give  intervals  correspond to  Interaction  becomes  and does  accomplished  validity  for  transportation  time  f o r e g o i n g d i s c u s s i o n on v a l i d a t i o n  simplified was  also  These  seconds  respectively.  output  9'  9*.  to c a l c u l a t e  in  many  the  whole  evidence this  work about  relatively  which the short  123 <% <X <X>  LOG SAWING -- OFFSET -OIA LEN TAPES --SWEEP" CUFT PCS I DENT PATTERN HOB VER IN FT IN/FT EDGE CVL ACTUAL LBR U l / I UH01 0.500 O.O 15 00 1.30 O 109 0.0 0.0 13.1 13  FBN LBR 117  FBM/ CHIP LUMBER BVPRO CUFT CUFT % % 9.73 2.6 20.53 3 81  COST %  0 0  GROSS * t CUNIT 33.34 193 5  <X HEDRG9' HE0RGB1 HS9-CE1 HR9-CG1 HR9-GM6 MB9-TWN HR8-CE3 HR8-CG2 HR8-GNG HR8-TWN CE1-TRM CG1-TWN CG1-0TW CG1-E0G C0< <X PASSES 3 3 1 5 2 <% SECONDS 39. SO. 10. 10. 12 <X t <X CE2-TRM CG2-TWN CG2-0TW CG3-EOG CC3-TM GNG-TWN GNG-OTW GNG-EOG GNG-TRW TWN-TWO TWN-EOG TWN-TRM DTK-TWO DTW-EDG P'w <X PASSES <X SECOkOS  <x t  <X TWO-TOT TWO-EOG TWD-TRM T01-E0G TO1-TRM EDG-TRM CHIPPER <X PASSES 2 2 <X SECONDS 4 <X S  /  SAWSIM PLOT U l / 1 UH01 2X06 8  2X08 a  3X0B 8  2X08 8  2X08 8  2X08 8  ONE INCH  • •  | 2X06 8  I  Figure  7.5.  discussion  "  L o g u s e d t o c h e c k machine  was  to present  utilization  the p r i n c i p l e s  statistics  of v a l i d a t i n g  To d i s c u s s a l l of t h e s t e p s t a k e n i n t h e v a l i d a t i o n beyond actions  the scope of t h i s taken  thesis.  in connection  However,  with v a l i d  process  certain  model  FLOWSIM. goes  additional  b e h a v i o u r must  be  mentioned. FLOWSIM w r i t e s e r r o r  messages  on t h e  output  file  in  the  124  SIMULATION STARTS  CHAIN #1 IS AVAILABLE AGAIN  CHAIN #1 BREAKS DOWN  LOG ARRIVAL; PROCESSING STARTS  HEADRIG 9 ' BREAKS DOWN  LOG PROCESSING ENDS  1  1  20  34  54  80  BLOCKED  BUSY 29  HEADRIG 9 ' IS AVAILABLE AGAIN '  20  180  DOWN  IDLE  26  100  302  . GPSS SEGMENT . OF CHAIN * 1 . BREAK DOWN  . . . . . . .  . . . . . . .  ...1..1 . 80 HRG9 DWNH9 100 HRG9 DWNH9  482  IDLE  . GPSS SEGMENT . OF HEADRIG 9 ' . BREAK DOWN  GENERATE ADVANCE FUNAVAIL SEIZE ADVANCE FAVAIL RELEASE TERMINATE  LAST PIECE LEAVES MILL; SIMULATION ENDS  GENERATE ASSIGN ADVANCE SUNAVAIL ADVANCE SAVAIL TERMINATE  SIMULATION TIME (SEC)  1.6 20 PI 34 PI  F i g u r e 7 . 6 . P r e d e t e r m i n e d breakdown e v e n t s and t h e e q u i v a l e n t GPSS p r o g r a m segments c a u s i n g t h e s e e v e n t s t o happen  case flow  of erroneous h e a d r i g logic  Auxiliary  is  programs  bucking  program  output  and  also  checked  DIA  be d e t e c t e d  input  selection  at  detect and  critical  segment points  e r r o r s caused format  w r i t e r program. by m o n i t o r i n g  operation the  program.  by m i s t a k e n l y  prepared  disagreement  of  between  E r r o n e o u s model  and  and p i e c e  checking  data  SAWSIM  o p e r a t i o n can transmitted  SIMULATION RESULTS OF MACMILLAN BLOEDEL WR3 SAWMILL DESIGN. 02:12 P.M. Sawmill  o p e r a t i o n was s i m u l a t e d f o r  MAR.  19. 1984  482 sec.  MACHINE UTILIZATIONS AND PIECE COUNTS. Name HRG9 HRG8 CMB1 CMB2 GANG TWIN EDGER TRMR1 TRMR2  T ime  Idle  333 .0 482 .0 454 ..0 482. 0 482. 0 482 ..0 470. 0 468..0 470 0  %  69 .0 100 O 94 . 1  ioo 6  100 0 1CO o 97 .5 97 .o 97 .5  Busy T ime 28.9 0.0 27.9 0.0 0.0  O.O  11.9 13.9 11.9  % 6.0 0.0 5.6 0.0 0.0 0.0 2.4 2.9 2.4  Blocked Time % 20.0 0.0 0.0 0.0 0.0 O.O 0.0 0.0 0.0  Down T ime  4. 1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  Piece Count  y. 20 .7 O .0 0 .0 b .0 0 0 0. 0 0 0 0 0 0 .0  99.9 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  1  o  4 0 0  o 2 7 6  TRANSPORTATION EQUIPMENT PIECE COUNTS. TRANSPORTATION PIECE COUNTS:  EQUIPMENTS:  BLT01 13  BLT02 0  BLT03 0  BLT04 2  BLT05  CHN01 4  CHN02 4  CHN03  CHN04  O  O  TRANSPORTATION PIECE COUNTS:  EQUIPMENTS:  CHN06 0  CHN07 0  CHN08 8  CHN09 7  CHN10 O  CHN1 1 0  CHN12 2  CHN13  CHN14  TRANSPORTATION PIECE COUNTS:  EQUIPMENTS:  CHN16 7  CHN17 6  R0L01 4  R0L02 0  R0L03 0  R0L04 0  R0L05 13  R0L06 0  TRANSPORTATION PIECE COUNTS:  EQUIPMENTS:  R0L09  R0L1O 0  ROLII 2  R0L12 0  R0L13 2  R0L14 0  UNSC1 8  UNSC2 7  O  O  O  CHN05 0  O  CHN15 O  R0L07 O  R0L08 O  1 26  between  auxiliary  selection,  DIA  programs.  matrices  For  in  i n s t a n c e , d a t a b a s e of  rectangular  form  boom l o g  etc.,  can  be  in both  the  monitored. The model  importance  building  development, contributed the  asked  test  run  found  validation  (test  recognized.  This  in  results  were  and  input  case,  also  data  results credible.  a  had  t o be  by of  changed  model  involvement  validity.  inputs.  back  of  management  reviewed feed  stages  managers were  c h e c k model  Sometimes, as  run)  to s i m u l a t i o n  garbage out"  t o d i s c u s s and  logic the  management c o o p e r a t i o n ,  to a l a r g e degree  specialists. model  and was  "garbage  being  of m i l l  To  avoid  continuously  "Good s e n s e "  subject-matter these until  of mill  discussions, managers  had  1 27  COMPUTER SIMULATION RUNS, RESULTS AND  In C h a p t e r interrelated be  thought  3,  the  flowchart  p h a s e s of t h e  activity,  producing  results  in  activities  require a large  programs.  The  performed Figure  and  a block  blocks  with  with of  hence a r e c a r r i e d  out  time  sequence  of  by  the  logic  of  Similarly,  the  execution  words,  making  a s i m u l a t i o n run,  be  i n mind w h i c h  programs must  kept  by  organized  program one  system  g i v e s an  The  and  overview  way  interacting  itself, the  d i s c u s s i n g the about  STRUCTURE OF  best  s y s t e m of  is a result  accordingly consists  8.1.  its  one  of t h e o b j e c t i v e s of  displaying  and  into  logical  the of  t o summarize is  an  easy  all  of  sense  this  are of  computer In  other  task. the  Hence, programs  programs. that  research.  s t r u c t u r e of two  computer  l i n k a g e s between  simulation results,  it  This  fulfills  Thus,  before  this  chapter  program  system,  parts.  INTERACTING  elements  i n the  data  procedure  order.  interacting  thesis  and  of c o r r e s p o n d i n g  i s not  These  activities  whole  can  sidelines,  corresponding  determined  the  phase  sidelines.  these  to h e l p the program e x e c u t i o n procedure, were  One  oblique  the  follow a precisely  depicts  calculations,  how  programs must when  3.2  vertical  amount  is dictated  3.2.  Figure  simulation procedure.  of as an  manipulation  of  DISCUSSION  the to  PROGRAMS  s i m u l a t i o n program depict  it  i n the  system form  and of a  128  flowchart.  When r u n s were made, t h e f l o w c h a r t  was  to  found  programs  to  sequence  and  data  between  be  extremely  execute what  blocks  flowchart  sawing  it  upper p a r t lower  or output  these of  input  affect  the a c t u a l  interactions  the  computer  experimenting There  and  cell  The  other  Other and  output  flowchart  programs.  unit  i n t o two by a h o r i z o n t a l is  simulation  sample  to  separate  programs  log preparation  dotted the  (lower  (upper  part) part).  t o make p e r c e p t i b l e how c h a n g e s o f t h e i t s output,  which  sawing and p i e c e  i s the input  flow  procedure  two i n p u t  bucking  writer  f o r the  simulation.  must  be  files  Seeing programs  rerun  when  o f t h e u p p e r p a r t : boom l o g  i n s t r u c t i o n s f o r the  for  t h e sample  (Appendix  are binary files.  and a r e  Numbers  numbers.  sawlog  two p r o g r a m s , D a t a Base #1 w r i t e r  files  with  the model.  boundaries  measurement  blocks  between t h e two p a r t s we know what  are only  measurements w i t h  these  partitioning  simulation  with  for  divided  pieceflow  possible  vertical  input/output  this  is  part,  with  8.1,  ones  is  and  on F i g u r e  computer p r o g r a m s , whereas t h e l a t t e r  from p r o g r a m s d e a l i n g w i t h Hence,  what  The  The p u r p o s e o f  actual  and  sidelines.  arrows a r e l o g i c a l  line.  t o what  u n i t numbers t o use t o t r a n s f e r  of b l o c k s  and  e i t h e r input  The  experimentation,  8.1,  programs.  f o r m e r ones r e p r e s e n t  along  the  I/O l o g i c a l  sidelines  represent  Figure  u s e f u l p r o v i d i n g guidance  during  T h e r e a r e two k i n d s oblique  in  files The  simply  bucking  program  s e l e c t i o n program.  (Appendix  8.1)  8.2) do n o t have e x t e r n a l  of communication  binary  files  referred  to  between  arrows  input.  programs  a r e not d i s p l a y e d by  and  on t h e  having  two  129  CELL BOUNDARIES OF SAWLOG SELECTION  BOOM LOG BUCKING MEASURMENTS • INSTRUCTIONS SCRATCH FILE TO WRITE OUT AND READ IN FROM '' ERROR MESSAGES ON TEfWlfWl,  BUCKING PROGRAM  DATA OUTPUT FOR I MONITORING PURPOSE51 SCRATCH •JJQ_A*MPLE SAWLOG/ i tATA BASE «1 : (/SELECTION / 6 1.JWW IRITER PROGRAM FILE 7 PROGRAM  i DATA OUTPUT  /  FOR MONITORING PURPOSES  y  10  11  5  7  |B  2  /UBC COMBINE/ 3 /SUBROUTINE /  3SCRATCH FILE! TABLE OF DATA BASE »1 FOR MONITORING PURPOSES  X  MEASURMENT PROGRAM  WRITER/ 17  OUTPUTS FOR SAWSIM RUNSJ  SAWING PATTERNS  — —SAWS ^- I—M J =-L  I  SAWSIM OUTPUTS (SAWING INSTRUCTIONS FOR FLOWSIM RUNS) DIA MATRICES IN RECTANGULAR|0>FORM FOR MONITORING PURPOSES  WRITER/ ROGRAM / 4PDIA ' MA2_ ATRIX READER PROGRAM  7^  •er  DATA BASE "2 OF NON-ZERO DIA MATRIX ENTRIES  DATA BASE »1 FOR BOOM LOG SELECTION.BUCKING DECISION.SAWING MODE SELECTION  •as  FLOWSIM /FOLLOWER CARD 'WRITER FOR BOOM LOG GENERATOR FUNCTION  SAWLOG WEIGHTS  BINARY INPUT AND RESULT FILES  (LOG SELECT / 'FILE WRITER/ PROGRAM / LOG SELECT FILE SA WR E S RESULTS OF MILL DYNAMICS  Figure  8.1.  Structure  PRODUCTION RESULTS  of i n t e r a c t i n g  programs  1 30  numbers are  as i n p u t / o u t p u t  partly  input  forvalidation  files  are  called  First,  l o g measurement  is  the input  two  input  sawlog  files  instruction  and/or  program  by  Consequently,  rerunning  case of changing As sawing The  by  the  using  the  i s only  pattern  files.  measurement  output  of  particular the right  these way hand  files,  boundaries. required  i n the  the  machines.  separate  SAWSIM.  complete  sawing  and t h e d i s t a n c e s  mill  to  create  proper  s e t up t h e two i n p u t  runs  to  managers on  sawing  corresponds  1, mode 2,  s i d e o f D a t a Base #1, F i g u r e  files,  pattern  SAWSIM r u n s must be made.  SAWSIM (mode  piece  C a r e f u l r e a d i n g of  important  F o r each p a i r of separate  files,  running  p o s i t i o n of the l o g or  A f t e r having  o f sawing  bucking  l o g measurement  describe  extremely  SAWSIM r u n s c a n be made.  the  input.  t h e number o f s a w l i n e s  found  if,  o f t h e sawlog  cell  SAWSIM manual and d e t a i l e d d i s c u s s i o n w i t h were  These  different  changing  files  of  simulation  i f , and o n l y  the accuracy  saws a s w e l l a s t h e p r o c e s s i n g  sawing  on  change  must a l s o be s e t up b e f o r e  terms  borderline,  program.  pattern  sawing p o l i c y  log  reader  i n d i c a t e s , beside  in  part.  i s D a t a Base #1 w h i c h  by v a r y i n g  between them, and t h e r e l a t i v e the  Second,  t h e upper p a r t  data  relevant  of lower  dotted  the flowchart files  files  f o r SAWSIM r u n s w h i c h a r e t h e  files.  t h e above  sawing p a t t e r n  process  files  changed  input  are  f o r t h e lower computer  o f t h e lower p a r t are  partly  the  o f FLOWSIM v i a i t s m a t r i x  lengths  selection  crossing  of input  are input  and  The o u t p u t  s i m u l a t i o n procedure  arrows  two k i n d s  procedure. so  two  u n i t numbers.  purposes,  f o r t h e computer  There indicating  logical  to  and Each one  mode 8 c o l u m n s 6.7).  Regarding  131  this  c o r r e s p o n d e n c e between  D a t a Base run  SAWSIM  output  and "mode" columns o f  #1, t h e r e a r e two c r u c i a l  points  t o keep  in  sawlogs  belonging to  FLOWSIM  different  free  from  "mode" columns  different  ways  of  sawing p a t t e r n s . patterns  and  #1  writer free  columns  serial  program,  #2.  output  of  program v i a sawing  #1  is critical.  1, mode  2,  ... o f  Since  i s lined  to the locations  these  locations  up a s i n p u t  input  Data  are  f o r t h e DIA  i s crucial  for error  simulation.  FLOWSIM  is  SAWSIM  carried  output  8.3) and t h e m a t r i x  The  writer  DIA  dynamic form  program  information  to  make  reader  program  the  presence  log  selections, Base  Whenever  finder  the  required  the  o f D a t a Base  #2  also  set  contained  subroutine  up  and  convenient  output  the  and  contains  required  program.  sawing  #2  hence  ensures boom  selections.  reader is  and  The m a t r i x  mode  by t h e m a t r i x  by D a t a Base  is called  information.  hence  #1 f o r FLOWSIM t o make p o s s i b l e  bucking d e c i s i o n s is  in  w i t h FLOWSIM  8.4).  One c o n t a i n s t h e  and  reader  by  program  (Appendix  The o t h e r  matrices  matrix  i s run t o g e t h e r  information  DIA  DIA  required  t h e DIA w r i t e r  outputs.  possible.  of  for  two  format  program  in rectangular  monitoring  format  the  reader  has  arrays  non-zero e n t r i e s  efficient  into  o u t by two p r o g r a m s ,  (Appendix  Data  to  Base  numbers r e f e r r i n g  t h e sequence of t h i s  Reformatting  only  Data  o f mode  i n D a t a Base  by how SAWSIM  t o t h e computer  c o r r e s p o n d e n c e between  of  i n columns  are actually  determined  o f D a t a Base #1 a r e r e p r e s e n t a t i v e s  Thus, the r i g h t  "mode"  of DIA m a t r i c e s  First,  sawing s u p p l i e d  S e c o n d , t h e numbers Base  error.  mind  program.  needed,  by FLOWSIM t o l o c a t e  the  and r e t u r n  1 32  Getting FLOWSIM  the  two d a t a  bases  run w h i c h p r o d u c e s weights.  showing  times  many  FLOWSIM d u r i n g t h e the  log  select  to produce select  file,  sawing  results  SAWSIM r u n s , carried  out  8.2.  breakdown. market  and  market  runs  simulation  for  SAWRES r e r u n s . binary  of  sample  serve  as  the  output:  results are  of  of mill  frequencies  Sawlog w e i g h t s  are  (Appendix 8.5)  whose t a s k  In  sawlogs for  stage  s a w l o g s were s e l e c t e d  addition  i n p u t and r e s u l t  base  up t h e  files  from total  to  input  the  containing  previously production  by to is log the  performed  calculations  by SAWRES. RESULTS OF SIMULATION RUNS AND DISCUSSION runs  the  were g r o u p e d a c c o r d i n g t o  effect  of  Accordingly, machinery only  various this  k i n d and  gained  by  running  results  are  not  and compared  and m i l l  simulated  for  one  (References  to  throughout  this  in  dynamics shift  8.2-8.3),  information  detail,  section).  the  results, 460  s i m u l a t i o n output  are  to  Among in d e t a i l  that  of the to  can  be  O t h e r market  run  but  they  are  to  get  operation  was  = 27600 s e c o n d s  [1].  table. U.S.A.  the  minutes  Numbers  corresponding  results  discussed  on  -  the  run i s of  of  and m a c h i n e r y  separately.  similar  only  objectives  runs,  i n a summarizing  now  production  market  discusses  s i m u l a t i o n programs.  discussed  Concentrating  segment  source  the  the  overseas markets  breakdown  the U . S . A .  the  (Figure  run.  sets  weights  sample  w r i t e r program  demonstrate  represented  the  the  Simulation analysing  Sawlog  file  input  it  two k i n d s of  d y n a m i c s and s a w l o g how  ready,  given on  numbers  mill  in the  market,  square  brackets  condensed  output  i n square brackets  of  SIMULATION RESULTS Of MACMILLAN BLOEDEL WR3 SAWMILL DESIGN. 01 . 35 P M Sawmill H*  C  Name  n o  HRG9 HRG8 CMB1 CMB2 GANG TWIN EDGER TRMR1 TRMR2  3  ro 3  w ro  06.  1984  o p e r a t i o n was simulated f o r 27600 nnc.  MACHINE UTILIZATIONS AND PIECE COUNTS.  l-f  ro  MAY  Busy T Ime  Idle T Ime 0.0 0.0 0.0 11.0 ,,1.4 395 460 18295 27600 100.0 1632 5.9 16. 1 4462 16.9 4673  TRANSPORTATION  P i e c e Count  Blocked  &  26069.0 27102.9 27204.9 27139.9 9304.9 0.0 25905.9 23137.9 22926.9  2842 2927 474 0 3385 11569 1 1464  -\13  EQUIPMENT PIECE COUNTS.7  o TRANSPORTATION PIECE COUNTS:  EQUIPMENT:  BLT01 9428  BLT02 8487  BLT03 5294  BLT04 3394  BLT05 0  CHN01 3055  CHN02 3050  CHN03 195  CHN04 3222  CHN05 3221  0 C rt  TRANSPORTATION PIECE COUNTS:  EQUIPMENT:  CHN06 280  CHN07 0  CHN08 13346  CHN09 13231  CHN10 0  CHN1 1 0  CHN12 3394  CHN13 0  CHN14 0  CHN15 0  C rt  TRANSPORTATION PIECE COUNTS:  EQUIPMENT:  CHN16 1 1593  CHN17 11482  R0L01 2843  R0L02 2928  R0L03 474  RDL04 0  R0L05 9457  R0L06 0  R0L07 8490  R0LO8 5305  TRANSPORTATION PIECE COUNTS:  EQUIPMENT:  R0L09 O  ROL10 O  R0L11 3385  R0L12 O  R0L13 3384  R0L14 0  UNSC1 13300  UNSC2 13175  co U)  MACHINE UTILIZATION BAR CHARTS.  IDLE STATE . (%)  HRIG9  HRIG8  ••* • •  ••*»« • *  *»•»« * *  COMB 1  COMB2  GANGE  TWIN  EOGER  TRIM!  TRIM2  COMB 1  COMB2  GANGE  TWIN  EOGER  TRIM1  TRIM2  BUSY STATE  {%)  HRIG9  HRIG8  BLOCKED STATE  (%)  iQ C CD  10 * ,  CO  6  to  4 *  o o  2 •  .  3  *  *  o  ft)  HRIG9  3 01  HRIG8  COMB 1  C0MB2  GANGE  TWIN  EDGER  TRIM1  TRIM2  COMB 1  C0MB2  GANGE  TWIN  EDGER  TRIM1  TRIM2  CD  f O  •  . • DOWN STATE  (%)  C/l  0  G rt TJ  C  rt  10 8 6 •  O O 3  4 2  Oi  o HRIG9  HRIG8  >>> NUMB.OF BOOM LOGS PROCESSED. BLOGC:  >>> OUEUE HRG90 HRG8Q  <<<  636  LOG OECK OUEUES  <<<  MAXIMUM CONTENTS 11 11  AVERAGE CONTENTS B.628 8.227  TOTAL ENTRIES 467 736  ZERO ENTRIES 1 2  PERCENT ZEROS 0.2 0.2  AVERAGE TIME/UNIT 509.957 308.531  (AVERAGE TIME/UNIT 511.051 309.371  QTABLE NUMBER  CURRENT CONTENTS 8 8  PERCENT ZEROS 366 79.9 94 .9 690 284 1 100.0 2926 100 0 474 10O.0 99.7 3375 7 0  AVERAGE TIME/UNIT 3.342 0.668 0.000 0.000 0.000 0.018  (AVERAGE T1ME/UNJ .641 -13. 133 0.000 O.OOO  QTABLE NUMBER 1 2 3 4 5 7  CURRENT CONTENTS O 0 0 0 0 O  >>> BLOCKED STATE STATISTICS OF MACHINES << OUEUE 0HRG9 QHRGB QCMB1 OCMB2 OGANG OEOGR  MAXIMUM CONTENTS  AVERAGE CONTENTS 0.055 0.017 0.000 0.000 O.OOO 0.002  TOTAL ENTRIES /~458 C—227  284 1 2926 474 3385  ZERO  JNI51I  >>>  TR.EQUIPMENT  STATISTICS  f ^ A VG - U T I L - P U R 1 N G - O TOTAL A V A I L UNAVL TIME TIME \^ TIME BLT 1 .046 BLT2 .038 BLT3 .064 BLT4 .201 CHN1 .717 CHN2 .922 CHN3 .017 CHN4 . 489 CHN5 .873 CHN6 .019 CHN8 . 123 CHN9 . 120 CHN12 .092 CHN16 .454 CHN17 .437 R0L1 .713 R0L2 .661 R0L3 . 123 R0L5 .052 R0L7 .042 R0L8 .073 R0L11 .696 R0L13 . 146 UNSC1 .368 UNSC2 . 362  STORAGE  r  <<< ENTRIES 197531 160575 104076 66949 48886 48804 4673 44534 44521 5182 214484 210872 55212 92874 91304 59848 55221 9229 198227 160626 104340 66745 66721 13300 13175  AVERAGE TIME/UNIT 17.003 17.005 44.287 21.482 54.673 93.890 19.049 40.927 97.470 18.792 109.689 108.910 91.702 48.628 47.598 10.206 10.245 16.306 7 .996 7.999 15.984 10.939 11.547 6. 118 6.076  CURRENT STATUS AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL AVAIL  PERCENT AVAIL 100.0 100.0 100.0 100.0 100.0 100.0 1O0.0 100.0 100.0 100.0 100.0 1000 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0  CAPACITY 2 GOO 2600 2600 258 135 180 180 135 180 180 6900 6900 1980 360 360 31 31 44 1 100 1 100 825 38 190 8 8  AVERAGE CONTENTS 121.691 98.937 167.003 52.110 96.838 166.023 3.225 66.038 157.228 3.528 852.411 832.106 183.444 163.634 157.462 22.132 20.498 5.452 37.431 46.554 60:429 26.454 27.914 2.948 2.900  CURRENT CONTENTS 192 0 136  o  66 168 19 0 150 0 748 • 948 148 198 134 24 17 0 696 51 264 0 0 0 6  MAXIMUM CONTENTS 946 837 1268 258 135 180 60 135 180 56 1632 1680 616 360 360 31 31 44 837 837 810 38 189 8 8  >> BLOCKED STATE STATISTICS OF TR.EQUIPM. < « OUEUE  MAXIMUM CONTENTS ARE 1 12 ARE2 1 ,15 /"ARE4 ~~ 1 lARE5.^ 14 ARE6 2 ARE7 2 ARE8 2 ARE9 11 ARE 10 1 ARE 12 1 ARE 13 15 ARE 14 2 ARE 15 1 ARE 19 1 ARE21 1 ARE23 1 ARE24 1 ARE25 1 ARE26 1 ARE27 1 ARE28 1 ARE29 2 ARE37 28 ARE38 30 ARE40 1 ARE41 1 ARE43 1 ARE44 1 ARE47 29 ARE48 32 ARE49 1 ARE50 30 ARE51 3 ARE52 1 ARE53 1  AVERAGE CONTENTS 5 .070 0 .508 0 .000 8 .787 0 .503 0 .006 0 .061 3 .666 0 .368 0 .000 9 .643 0 .427 0 ,006 0 OOO 0 .OOO 0 OOO 0 .000 0 .000 0 .000 0 .000 0 .000 0,.020 2 .350 2 . 188 0 .001 0..004 0 .002 0 .002 5 307 4..811 0. 000 6 .346 0 966 0. 000 0. 000  TOTAL ENTRIES 3055 3051 195 2853 2843 194 474 3222 3221 280 2938 2927 280 9428 5294 8487 4706 4714 2698 2588 4261 4799 13300 13176 1707 1 1593 1687 1 1482 11579 11470 3394 3385 3385 1681 1703  ZERO ENTRIES 82 1143 195 15 350 177 319 271 1734 280 50 391 268 9428 5294 8487 4706 4714 2698 2588 4261 4226 2120 2142 1698 11511 1674 11442 749 804 3394 406 137 1681 1703  PERCENT ZEROS 2 .6 37 .4 100 .0 0 .5 12 .3 91 .2 67 .2 8 .4 53 .8 100 .0 1 .7 13 .3 95 .7 100..0 100 .0 100 O 100. 0 100 .0 100 .0 100 .0 100 .0 88 0 15 9 16 .2 99. 4 99. 2 99. 2 99. 6 6..4 7. 0 100. 0 11 .9 4 .0 100. 0 100. 0  AVERAGE TIME/UNIT 45 .808 4 .597 0 .OOO 85 .006 4 .888 0 .989 3 .559 31 .408 3 . 154 0 .000 90 .590 4 .028 0 .685 0 .000 0 OOO 0 .000 0 .000 0 .000 0 .000 0 .000 0 000 0 , 119 4 .878 4 .584 0 028 0 01 1 0 035 0 005 12 .651 11 .578 0 000 51 748 7 .877 0. 000 0. 000  (AVERAGE TIME/UNIT 47 .072 7 .351 0 .000 85 .455 3 .374 11 .294 10 .883 34 .292 6 .833  0 .000  92.. 156 4..649 16..000 0 000 0 000 0..000 0. 000 0. OOO 0. OOO 0 .000 0. 000 1. 000 5. 803 5.,474 5. 333 1. 583 4. 615 1 550 . 13. 326 12. 451 0. 000 58. 801 8. 209 0. 000 0. 000  QTABLE NUMBER  CURRENT CONTENTS 4 1  0  10 1  0  0 0 0  0  10 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 10 6 0 0 0 0 0  0000 0000DRIG9 - NUMBER OF OBSERVATIONS WITHIN FREQUENCY CLASSES OF RLOCKED STATE WAITING  1  61  121  181  241  301  361  421  481  54 1 601  661  721  781  841  901  961 1021 1081 1141+  0000 0000RIG8 - NUMBER OF OBSERVATIONS WITHIN FREQUENCY CLASSES OF BLOCKED STATE WAITING  1  61  121  181  241  301  361  421  481  541  601  661  721  781  841  901  TIMES.  TIMES.  961 1021 1081 1141+  0000  (J.  10 * * * * *  d M  (D  *  EDGER  - NUMBER OF OBSERVATIONS WITHIN FREQUENCY CLASSES OF BLOCKED STATE WAITING TIMES.  ****  8 * * * • * . . . . .  00  to 2  .  *  *  .  *  •  *  »  O O Oi fl>  3  W CD Oi  *1 t* O -U  CO H 2 O d rt d rt  o  O  3  O.  1  61  121  181  241  301  361  421  481  54 1  601  661  721  781  841  901  961  1021  1081  1141*  TOP END DIAMETER DISTRIBUTION ( S L O G )  • 15  16  17  18  19  20  * * * *< 21  22  23  24  25  26  27  28  •  •*