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Application of work sampling to short cycle assembly operations 1978

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APPLICATION OF WORK SAMPLING TO SHORT CYCLE ASSEMBLY OPERATIONS by HUMBERTO ̂ VILLALOBOS CASILLAS B.Eng., Instituto Politecnico Nacional, Mexico D.F., 1973 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in the Faculty of Graduate Studies in the Department of Mechanical Engineering We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1978 ^^Humberto V i l l a l o b o s C a s i l l a s , 1978 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make i t freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Humberto VILLALOBOS Casillas. Department of Mechanical Engineering The University of British Columbia 2075 Wesbrook Place Vancouver, B.C. Canada V6T 1W5 June 26, 1978. i i ABSTRACT The o b j e c t i v e of t h i s work i s to study the a p p l i c a b i l i t y of work sampling to a s h o r t c y c l e r e p e t i t i v e o p e r a t i o n and to compare the economics of work sampling technique with a c o n v e n t i o n a l time study. To make t h i s comparison, work sampling s t u d i e s were c a r r i e d out c o n c u r r e n t l y with ongoing time s t u d i e s done by personnel of the I n d u s t r i a l Engineering department i n a l o c a l lock f a c t o r y . The c r i t e r i a f o r the study were : 1. - The base data would ensure that the p r e d i c t i o n s would be w i t h i n + f i v e percent of the true value with 95% c e r t a i n t y . These are standard confidence l i m i t s f o r most i n d u s t r i a l a p p l i c a t i o n s . 2. - P r e p a r a t i o n time f o r work sampling and time study were assumed to be equal. Two o p e r a t i o n s were s t u d i e d , a l i n e assembly o p e r a t i o n and a bench assembly o p e r a t i o n . The f i r s t study r e p r e s e n t s the work of a team of four people as a u n i t . The workers o f t e n changed t h e i r a c t i v i t i e s to achieve a b e t t e r balance of the l i n e , s i n c e the nature of the o p e r a t i o n i s such that i t i s p r a c t i c a l l y i m p ossible to have the workers at f i x e d p o s i t i o n s performing the same a c t i v i t y a l l the time. i i i The second a c t i v i t y r e p r e s e n t s numerous workers working independently at benches. The study proved that f o r assembly o p e r a t i o n s work sampling can be used to good e f f e c t and at v i a b l e c o s t when compared with standard stop watch study. The a c c e p t a b i l i t y o f the s t u d i e s p s y c h o l o g i c a l l y favours work sampling, as does the l e v e l of t r a i n i n g r e q u i r e d for the time study p r a c t i t i o n e r . I t i s g e n e r a l l y accepted that a work sampling a n a l y s t could be t r a i n e d i n one-quarter of the time which would be r e q u i r e d f o r time study. Approved by : P r o f . N. E l e y i v TABLE OF CONTENTS Ab s t r a c t ................................... ....... i i T a ble of Contents i v Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v i CHAPTER I INTRODUCTION TO WORK MEASUREMENT ............... 1 1.1 P r o d u c t i v i t y •••........... ............ ......• 1 1.2 Management r a t i o s .......................... 5 1.3 D i r e c t means of improving p r o d u c t i v i t y ..... 4 CHAPTER I I TECHNIQUES OF WORK HEASUREHENT ................. 7 2.1 Terms used i n work measurement ............. 7 2.2 Stop-watch time study 10 2.3 Repre s e n t a t i v e samples of times 12 2.4 Rating 14 2.5 Determining the number of readings 15 2.6 Determining production standards ...........17 CHAPTER I I I WORK SAMPLING ..................... ...... ....... 18 3.1 I n t r o d u c t i o n ............................... 18 3.2 An example of sampling ..................... 19 3.3 Confidence l e v e l ...........................20 3.4 Accuracy of work sampling ..................22 3.5 Example of accuracy . .... ............. ...... 23 3.6 Accuracy f o r a given number o f o b s e r v a t i o n s 24 3.7 Determining production standards ...........25 V CHAPTER IV APPLICATION OF COMPUTERS TO WORK SAMPLING ......28 4.1 I n t r o d u c t i o n ...... •. . • •. •.•• •.• • •....• ••...28 4.2 D e s c r i p t i o n o f th e l i n e .29 4.3 The study .... ................... ........... 35 4.4 Bati n g i n work sampling ....................40 4.5 Schmid's computer programme ................42 4.6 Random times f o r ob s e r v a t i o n s ..............46 4.7 A p r a c t i c a l a p p l i c a t i o n o f Schmid's programme ......................... 48 4.8 R e s u l t s from stop-w,atch s t u d i e s ............54 4.9 Time r e q u i r e d t o s e t the standard ..........55 4.10 Summary of t h i s chapter ................... 56 CHAPTER V WORK SAMPLING IN A SHORT CYCLE OPERATION 57 5.1 Work sampling i n department 41 L a t c h Assembly ...............57 5.2 Time r e g u i r e d t o s e t the standard time .....66 5.3 Summary o f t h i s chapter .................... 67 CHAPTER VI CONCLO SIONS .............•..«.... .......•....... 6 8 B i b l i o g r a p h y ................ ••••»«••»•«•• ••• •'»»«»«» . 70 Appendix A ........................................ 71 Appendix B . . . • . • . . » « • • • « • • • • • » » . . . . . . » . . • . . . • 75 Appendix C 80 Appendix D ........................................ 83 Appendix E 92 v i ACKNOWLEDGEMENTS The author wishes to express h i s profound g r a t i t u d e to P r o f e s s o r Norman Eley f o r h i s guidance and encouragement towards the completion o f t h i s work. Mr. Eley has not only been an e n t h u s i a s t i c a d v i s o r , but a l s o a good f r i e n d who has helped me throughout my graduate s t u d i e s . Deepest a p p r e c i a t i o n i s extended to the personnel of the I n d u s t r i a l Engineering department a t Heise r Lock Co. o f Canada f o r t h e i r c o o p e r a t i o n d u r i n g the c o l l e c t i o n of data f o r t h i s t h e s i s and a l s o f o r g i v i n g access t o t h e i r own r e c o r d s . The author i s f u r t h e r i n d e b t e d t o Miss Katherine Kassay f o r her pa t i e n c e and e f f o r t i n the p r e p a r a t i o n of t h i s t h e s i s . 1 CHAPTER , 1 INTRODUCTION TO WORK MEASUREMENT The measurement of human work i s an i n t e g r a l p a r t of p r o d u c t i v i t y . 1.1 PRODUCTIVITY P r o d u c t i v i t y has been g e n e r a l l y d e f i n e d as: PRODUCTIVITY = (OUTPUT) / (INPUT) In p r i n c i p l e , t h i s p r o d u c t i v i t y r a t i o i s a simple and s t r a i g h t f o r w a r d one, but i f an attempt i s made t o apply such a measurement over too l a r g e an area then c o n s i d e r a b l e complexity may r e s u l t . F a i r l y simple examples may be the number of words typed per minute by a s e c r e t a r y or the number of c u b i c meters dug by a l a b o u r e r per day. On the other hand, when p r o d u c t i v i t y i s a p p l i e d t o a f a c t o r y , the i n p u t and output would have t o be expressed i n a common g u a n t i f i c a t i o n f a c t o r . Problems a r i s e i n d e f i n i n g t h i s f a c t o r . Not only i s t h e r e d i f f i c u l t y with the e v a l u a t i o n of the i n p u t (manpower, m a t e r i a l s and c a p i t a l equipment) i n homogeneous u n i t s , but a l s o with the e v a l u a t i o n o f the output. 2 There have been s e v e r a l attempts t o e v a l u a t e the p r o d u c t i v i t y r a t i o . Smith and Beeching 1 suggested a f a c t o r c a l l e d 'man-year e q u i v a l e n t s * . These were obtained by d i v i d i n g the a c t u a l sum of money spent on the resources by the average i n d u s t r i a l income a t t h a t time. C a p i t a l investment would, o f course, r e q u i r e a f u r t h e r d i v i s i o n by the years of a m o r t i z a t i o n . By adding together eguivaletst man-years of manpower, m a t e r i a l s and c a p i t a l eguipment, an ex p r e s s i o n of i n p u t i s d e r i v e d which takes i n f l a t i o n i n t o account. T h i s sum was c a l l e d the 'resources-man-years*. W i l l i a m T. Stewart i n h i s a r t i c l e on p r o d u c t i v i t y 2 d e s c r i b e s and g i v e s a p r a c t i c a l a p p l i c a t i o n of a d i f f e r e n t ' y a r d s t i c k * f o r measuring the e l u s i v e p r o d u c t i v i t y concept. Mr. Stewart uses the Keeney model of m u l t i p l i c a t e m u l t i a t t r i b u t e u t i l i t y f u n c t i o n , i n which a r e p r e s e n t a t i v e management group e s t a b l i s h e s u t i l i t y values f o r v a r i o u s departments t o he l p determine p r o d u c t i v i t y g o a l s . * Dennis A. Hhitmore, WORK MEASUREMENT, (Great B r i t a i n , B u t l e r S Tanner L t d , 197 5) p. 2. 2 William T. Stewart: IE PRODUCTIVITY SERIES, V o l . 10 No. 2 of The J o u r n a l o f I n d u s t r i a l Engineering (February 1978), p. 58. 3 T h i s group s e l e c t s the r e l e v a n t r a t i o s t h a t a f f e c t p r o d u c t i v i t y such as i n v e n t o r y turnover (cost of goods sold/average i n v e n t o r y ) , value added per d i r e c t l a b o u r hour, key machine e f f i c i e n c y (a percent t h a t r e f l e c t s the a c t u a l u t i l i z a t i o n of high investment machines), m a t e r i a l i d e n t i f i c a t i o n and l o c a t i o n accuracy, t o t a l o p e r a t i n g q u a l i t y c o s t per net s a l e s d o l l a r , and so on. These f a c t o r s would depend e n t i r e l y upon the i n d u s t r y under study. The r e p r e s e n t a t i v e management group would s e l e c t and decide the number o f r a t i o s t o take i n t o account. The r a t i o s a r e m u l t i p l i e d by the s c a l i n g f a c t o r s (rank) and added together g i v i n g what Stewart c a l l s the •composite p r o d u c t i v i t y u t i l i t y measure'. The t o t a l p r o d u c t i v i t y i s a broad long-term guide to the s e n i o r management d e s c r i b i n g progress of the company. I t does not p o i n t out the s p e c i f i c areas t h a t may need c o r r e c t i v e a c t i o n . T h i s l e a d s us to the next s e c t i o n i n which an attempt i s made t o s u b d i v i d e p r o d u c t i v i t y . 1.2 MANAGEMENT BATIOS Th i s i s another way of measuring p r o d u c t i v i t y . They are f i n a n c i a l r a t i o s r a t h e r than measurements r e l a t e d t o a d e f i n e d y a r d s t i c k such as the •man-year*. 4 Dun & B r a d s t r e e t p u b l i s h e s the 'Key B u s i n e s s R a t i o s i n Canada*, a y e a r l y c o m p i l a t i o n of over 150 l i n e s of r e t a i l i n g , w h o l e s a l i n g , manufacturing and c o n s t r u c t i o n businesses. Examples of these r a t i o s might be: PROFIT SALES „ SALES - TANGIBLE NET WORTH SALES INVENTORY I t has been claimed t h a t management r a t i o s d e r i v e d i n t h i s way can be used t o compare the * s t a t e of h e a l t h * of d i f f e r e n t companies i n the same l i n e of b u s i n e s s . From the above d i s c u s s i o n , i t becomes c l e a r t h a t i n most manufacturing companies, the concept c f p r o d u c t i v i t y measurement i s a complex one. 1.3 DIRECT BEANS OF IMPROVING PRODOCTIVITY. Against t h i s g e n e r a l background, i t i s now p o s s i b l e t o d e f i n e work measurement and understand i t s importance. G e n e r a l l y speaking, p r o d u c t i v i t y can almost always be i n c r e a s e d by heavy investment of money i n new and improved p l a n t s or eguipment. T h i s r i s e i n p r o d u c t i v i t y u s u a l l y takes time i n p l a n n i n g , s e a r c h i n g , implementing and t e s t i n g . 5 On the other hand, an i n c r e a s e i n p r o d u c t i v i t y can a l s o be obtained by r e d u c i n g wasted human e f f o r t and time i n o p e r a t i n g the manufacturing process or e l i m i n a t i n g unnecessary movements. The syst e m a t i c approach of reducing the work content of the manufacturing process i s c a l l e d method study, and the technique of l o c a t i n g i n e f f e c t i v e time and s e t t i n g standards of performance i s c a l l e d work measurement. The formal d e f i n i t i o n s a r e : 1 •Method study i s the s y s t e m a t i c r e c o r d i n g and c r i t i c a l examination of e x i s t i n g and proposed methods of doing work, as a means of developing and 'applying e a s i e r and more e f f e c t i v e methods and reducing c o s t 1 2 •work measurement i s the a p p l i c a t i o n of techniques designed t o e s t a b l i s h the time f o r a q u a l i f i e d worker t o c a r r y out a s p e c i f i e d job at a d e f i n e d l e v e l of performance * Method study and work measurement are c l o s e l y l i n k e d . Method study s i m p l i f i e s the job and develops more economical ways of doing i t , while work 1 These d e f i n i t i o n s were adopted from: I n t e r n a t i o n a l Labor O f f i c e : INTRODUCTION TO HORK STUDY REVISED EDITION {Switzerland, Impression C o l e u r s Heber, 1974), Appendix 5, p. 413 - 424. 6 measurement i s concerned with the dete r m i n a t i o n of how long i t should take t o do the job. Work measurement pr o v i d e s the management with a means of measuring the time taken t o perform the o p e r a t i o n s i n such a way t h a t the i n e f f e c t i v e time w i l l show up and can then be separated from the e f f e c t i v e time. Work study a c t s l i k e a surgeon's k n i f e , l a y i n g bare the a c t i v i t i e s of a company and t h e i r f u n c t i o n i n g , good or bad, f o r a l l to see. There i s nothing l i k e i t f o r "showing up" people, and f o r t h i s reason i t oust be handled, l i k e the surgeon's k n i f e , with s k i l l and c a r e . Nobody l i k e s being shown up, and u n l e s s the work s p e c i a l i s t d i s p l a y s g r e a t t a c t i n his h a n d l i n g of people he may arouse the animosity of management and workers a l i k e , which w i l l make i t impossible f o r him to do h i s job p r o p e r l y . 7 CHAPTER I I TECHNIQUES OF,WORK MEASUREMENT The e x i s t i n g techniques of work measurement are b r i e f l y d e s c r i b e d i n t h i s chapter. Before o u t l i n i n g the techniques of work measurement, the f o l l o w i n g terms should be d e f i n e d : * 2.1 TERMS USED IN WORK MEASUREMENT Observed Time The time taken to perform an element or combination o f elements obtained by means of d i r e c t measurement. Element .- A d i s t i n c t part o f a s p e c i f i e d job s e l e c t e d f o r convenience of o b s e r v a t i o n , measurement and a n a l y s i s . Standard Performance or Standard Pace . ? The r a t e of output which q u a l i f i e d workers w i l l n a t u r a l l y achieve without o v e r - e x e r t i o n as an average over the working day or s h i f t provided they know and adhere t o the s p e c i f i e d method and provided they are motivated to apply themselves to t h e i r work. This performance i s denoted as 100 on the standard r a t i n g . 1 These d e f i n i t i o n s were adopted from: I n t e r n a t i o n a l Labor O f f i c e : INTRODUCTION TO HORK STUDY REVISED EDITION ( S w i t z e r l a n d , impression C o l e u r s Weber, 1974), Appendix 5, p. 413 - 424. 8 Bating . - The assessment of the worker's r a t e of working r e l a t i v e t o the observer's concept o f t h e r a t e corresponding to standard pace. , B a s i c Time or Normal Time .- The time f o r c a r r y i n g out an element of work a t standard r a t i n g , ±,.e;r Observed Time x Observed B a t i n g Standard Bating Standard,Time . - The t o t a l time i n which a job should be completed a t standard performance, i . e . work co n t e n t , r e l a x a t i o n allowances, unoccupied time and i n t e r f e r e n c e allowances, where a p p l i c a b l e . R e l a x a t i o n Allowances .- An a d d i t i o n to the b a s i c time intended t o provide the worker with the o p p o r t u n i t y t o recover from the p h y s i o l o g i c a l and p s y c h o l o g i c a l e f f e c t s of c a r r y i n g out s p e c i f i e d work under s p e c i f i e d c o n d i t i o n s and to allow a t t e n t i o n to personal needs. The amount of allowance w i l l depend on the nature of the job. The a v a i l a b l e technigues may be d i v i d e d i n t o t h r e e major groups : stop-watch time study, s t a t i s t i c a l standards {work sampling) and predetermined motion time system. Stop-watch time study i s a technique f o r r e c o r d i n g the times and r a t e s f o r working f o r the elements of a s p e c i f i e d job c a r r i e d out under s p e c i f i e d c o n d i t i o n s , and f o r a n a l y s i n g the data to o b t a i n the time necessary 9 f o r c a r r y i n g out the job at a d e f i n e d l e v e l of performance. S t a t i s t i c a l standards or work sampling, i s a technique i n which a l a r g e number of i n s t a n t a n e o u s o b s e r v a t i o n s are made over a p e r i o d of t i s e of a group of machines, manufacturing processes or workers. Each o b s e r v a t i o n r e c o r d s what i s happening a t t h a t i n s t a n t and the percentage of o b s e r v a t i o n s recorded f o r a p a r t i c u l a r a c t i v i t y or delay i s a measure of the percentage of time d u r i n g which t h a t a c t i v i t y or delay occurs. Stop-watch and work sampling i n v o l v e the measurement of a c t u a l observed time and i t s adjustment to o b t a i n normal time by means of performance r a t i n g . Predetermined Motion Time System i s a technique whereby times e s t a b l i s h e d f o r b a s i c human motions ( c l a s s i f i e d a c c o r d i n g t o the nature of the motion and the c o n d i t i o n s under which i t i s made) are used t o b u i l d up the time f o r a job a t a d e f i n e d l e v e l of performance. 10 2.2 STOJ-IATCH_TIMJ_STUDY The 'Survey of Work Measurement and Wage I n c e n t i v e s ' 1 c a r r i e d out by Robert S. Sic e i n c o l l a b o r a t i o n with Patton C o n s u l t a n t s and A.I.I.E. showed t h a t the most p r e v a l e n t approach t o work measurement c u r r e n t l y used by American and Canadian i n d u s t r i e s i n v o l v e s a stop watch time study and simultaneous performance r a t i n g of the o p e r a t i o n to determine normal time. The procedure i n v o l v e s the f o l l o w i n g steps. 1.- Recording the standard method and i d e n t i f y i n g the u n i t of work. The f o l l o w i n g items are g e n e r a l l y i n c l u d e d : a) The department i n which the job i s performed. b) Job number. c) Product, m a t e r i a l s p e c i f i c a t i o n s , and i d e n t i f i c a t i o n as r e l a t e d to the o p e r a t i o n . d) Work place l a y o u t and dimensions. e) T o o l d e s c r i p t i o n s . .£) Feeds and speeds of machines. , * Rice R. : SURVEY OF WORK MEASUREMENT ANB HA€E INCENTIVES, V o l . No. 7 o f The J o u r n a l of I n d u s t r i a l E n g i n e e r i n g , ( J u l y 1977), p. 18 11 2. - S e l e c t i n g the operator f o r the study. He has to be experienced and t r a i n e d i n the standard method. 3. - Determining the elemental s t r u c t u r e of the o p e r a t i o n f o r timing purposes. The c r i t e r i o n to be followed i s t h a t end p o i n t s have t o be e a s i l y detected and defined* 4. - Observing and r e c o r d i n g the time r e q u i r e d f o r each element. During the o b s e r v a t i o n s , the worker i s being r a t e d . 5. - Determining the number of c y c l e s t o study. T h i s number depends on the d u r a t i o n of the b a s i c time of the c y c l e , and on the d i s p e r s i o n of the b a s i c times obtained d u r i n g the study. A common p r a c t i c e i s to take ten readings i n i t i a l l y of b a s i c time c y c l e s , and from these readings c a l c u l a t e the number o f c y c l e s to study. (This t o p i c w i l l be covered i n the next s e c t i o n ) . ., 6. - Computing normal time = average observed time x average r a t i n g factor/100 7. - Determining standard time = normal time( 1 • allowances i n percent) V 12 2.3 REPRESENTATIVE SAMPLES OF TIMES Seme v a r i a t i o n i n the c y c l e time almost always o c c u r s , even i f the worker under o b s e r v a t i o n i s not attempting to vary h i s pace. T h i s could be due to the random v a r i a t i o n i n the o p e r a t o r ' s pace, p o s i t i o n of the p a r t s worked with, p o s i t i o n of the t o o l s used, or simply v a r i a t i o n caused by s l i g h t e r r o r s by the time study person i n t i m i n g the worker. A reasonable l i m i t i n the number of r e a d i n g s i s to take enough to make the chances 95 out of 100 t h a t the observed average time w i l l be * 5 per cent of the t r u e average T h i s i s c a l l e d i n S t a t i s t i c s 95 per cent c o n f i d e n c e with + 5 per cent of the standard e r r o r of the mean. T h i s c r i t e r i o n has proved t o be a c c u r a t e enough i f time s t u d i e s are going t o be used f o r e s t a b l i s h i n g i n c e n t i v e wages, s i n c e • 5 per cent o f the standard u s u a l l y approximates a b a r g a i n a b l e increment i n wages. 2 The sampling theory i n v o l v e s b a s i c a l l y two formulae, Egs. 2.1 and 2.2. Both are based on the 1 True average i s d e f i n e d as the average value t h a t a time study person would f i n d i f he were t o spend h i s l i f e t i m i n g the worker. 2 Hundel M. : HANDBOOK OF INDUSTRIAL ENGINEERING AND MANAGEMENT, SECOND EDITION, P r e n t i c e - H a l l , 1971, p. 267. 13 assumption t h a t random causes are c o n t r o l l i n g the length of time o f the c y c l e . In most c a s e s , t h i s i s a reasonable assumption *. S = [ / N I I 2 - ( I X ) * ' . J /N (2.1) 8HEBE : S = Standard d e v i a t i o n . X = Bated i n d i v i d u a l r e a d i n g s . £ = Sum of homogeneous elements. N = Number o f readings of an element. The standard e r r o r of the mean Sx i n d i c a t e s the probable v a r i a b i l i t y o f the averages of groups of N values of X about the obtained mean or average of a l l readings of an element. I t can be computed by Eg. 2.2. Sx = syT (2.2) The property o f t h i s l a s t measure i s such t h a t 95 per c e n t 2 of the probable values o f the average f o r the element w i l l l i e w i t h i n • 2Sx of the tr u e average. 1 These equations are d e r i v e d and e x p l a i n e d i n Appendix A. 2 A c t u a l l y 95.4 per cent, but i t i s u s u a l l y rounded o f f to 95. 14 T h e r e f o r e , i f 2Sx i s l e s s than or equal to 5 per cent of the mean value, i t may be s a i d t h a t the chances are at l e a s t 95 out of 100 that the average f o r the element i s w i t h i n + 5 per cent of the t r u e average. Eqs. 2.1 and 2.2 are combined, and • 2Sx i s s e t equal to 5 per cent of the mean value. The f i n a l equation 2.3 i s s o l v e d f o r the number of readings N* r e q u i r e d to ensure 95 per cent c e r t a i n t y t h a t the obtained average r e a d i n g w i l l be w i t h i n • 5 per cent of the t r u e average c y c l e . » ' = C 40 / N ZIX2 - { r x i ' i z (2.3) where : N* = Number o f r e a d i n g s needed computed from N. N = Number of c y c l e s or r e a d i n g s taken at the time of computing N *. T h i s eguation i s e a s i l y t r a n s l a t e d i n t o i n s t r u c t i o n s f o r a p o r t a b l e programmable c a l c u l a t o r . 1 2.4 EATING In r e c e n t s t u d i e s the r a t i n g f a c t o r has proved to play an important r o l e i n o b t a i n i n g the standard time. *A programme f o r a Hewlett Packard C a l c u l a t o r model 25 i s found i n Appendix B. 15 B a t i n g i s th a t process during which the time-study a n a l y s t compares the performance {speed or tempo) of the operator under o b s e r v a t i o n with the observer*s own concept of normal performance. Bating i s a matter of judgment on the par t of the time-study a n a l y s t , and u n f o r t u n a t e l y judgement i s an i n d i s p e n s a b l e f a c t o r i n s e t t i n g a time standard f o r an o p e r a t i o n . S i n c e r a t i n g i s a s u b j e c t i v e judgment e n t e r i n g the computation of the time standard, the immediate q u e s t i o n that comes to mind i s : "How a c c u r a t e l y can experienced people r a t e ? " . C o n t r o l l e d s t u d i e s , i n which f i l m s from d i f f e r e n t i n d u s t r i e s showed workers performing a t d i f f e r e n t r a t e s , proved t h a t experienced a n a l y s t s c o u l d come t o an agreement i n r a t i n g w i t h i n •• • 3 per cent 1 . 2.5 DETERMINING THE NUMBER OF BEAPINGS A PRACTICAL APPLICATION Consider the time study c a r r i e d out i n one of the l o c a l manufacturing f i r m s . In t h i s c a s e , the c y c l e time was taken as one s i n g l e element, due t o the short elapsed time of the » Buffa E. : MODERN PRODUCTION MANAGEMENT, (New York, John Wiley 6 sons, 1973) p. 423. 1 6 c o n s t i t u e n t elements. The r a t i n g was posted as 100, s i n c e a c c o r d i n g to the time study man the worker under o b s e r v a t i o n was performing at normal pace. The f i r s t ten r e a d i n g s i n minutes were: .28 .35 .24 .31 .25 .25 .28 ,26 .25 ,28 Applying the Eg. 2.3 o r making use of the programme mentioned.above, the f i r s t estimate of the necessary number o f r e a d i n g s i s obtained: N • = 2 2 Readings, and. Average r e a d i n g = .283 Minutes. More data were obtained. A f t e r each r e a d i n g , the number of r e g u i r e d c y c l e s was found u s i n g a p o r t a b l e programmable c a l c u l a t o r . *** In t h i s case, 20 readings were enough to be i n c l u d e d w i t h i n the 95 % c o n f i d e n c e l i m i t s w i t h i n ± 5 % of the t r u e mean. The average r e a d i n g was .271 min. T h i s average r e a d i n g i s c a l l e d 'observed time*. The normal time i s found by a p p l y i n g the f o l l o w i n g equation : NORMAL TIME = { OBSERVED TIME } X { RATING } (2.4) In t h i s case, the a n a l y s t r a t e d the o p e r a t o r at *** See Appendix C 17 100 %, so the normal time and the observed time were equal. 2.6 DETERMINING PRODUCTION STANDARDS The standard time i s found by a p p l y i n g the f o l l o w i n g equation which i n c l u d e s the p e r s o n a l and f a t i g u e allowances., STANDARD TIME = NORMAL TIME (1+R EL AX ATION ALLOWANCES) (2.5) In t h i s case : Standard Time = .271 x 1.15 = .312 min. or STANDARD OUTPUT •— 192 Parts/hour. 18 CHftPTES I I I WORK SA BPIIBG 3 • 1 INTBODOCTION Work sampling i s a method commonly used to estimate the p o r t i o n o f time t h a t an a c t i v i t y o c c u r s , without n e c e s s i t a t i n g continuous o b s e r v a t i o n . I t i s a f a c t f i n d i n g method based on the laws of p r o b a b i l i t y , e s p e c i a l l y the bi n o m i a l d i s t r i b u t i o n . The f i r s t a r t i c l e d e s c r i b i n g work sampling, known at t h a t time as the "Snap Reading Method*, was pu b l i s h e d by L.H.C. T i p p e t i n 1935. Work sampling i s a l s o c a l l e d a c t i v i t y sampling, r a t i o delay method, and random o b s e r v a t i o n method. Work sampling has the f o l l o w i n g uses : 1»~ R a t i o , d e l a y .- To e v a l u a t e the a c t i v i t i e s and delays o f man or machine. 2. - Performance sampling Same as r a t i o delay i n c l u d i n g a r a t i n g f a c t o r during t h e p r o d u c t i v e p o r t i o n . 3. - Establishment of standard time .- In some s t u d i e s where the output and the ela p s e d time of the study are recorded, i t i s p o s s i b l e t o estimate the standard time. 19 In t h i s paper work sampling i s used to e s t a b l i s h standard times s i n c e both t h e output and the time a t which the sampling i s done are kept f o r f u r t h e r computations. work sampling i s based upon the laws of p r o b a b i l i t y . A sample randomly taken from a p o p u l a t i o n tends to f o l l o w the same patte r n o f d i s t r i b u t i o n as the p o p u l a t i o n . I f the sample i s l a r g e enough, the c h a r a c t e r i s t i c s of the sample w i l l d i f f e r l i t t l e from the c h a r a c t e r i s t i c s o f the group. Moreover, i t i s p o s s i b l e t c p r e d i c t the accuracy of the d i f f e r e n c e with a degree of c e r t a i n t y . 3. 2 AH, EXAMPLE OF,,,SAMPLING. Suppose we want t o estimate the p r o p o r t i o n of time t h a t a worker, or group of workers, spend working and not working. T h i s could be accomplished by long term stop-watch s t u d i e s i n which e i t h e r the p r o d u c t i v e or non-productive times are recorded. T h i s i s a lengthy and consequently c o s t l y approach. Instead, suppose t h a t a l a r g e number of o b s e r v a t i o n s are taken a t random times. The outcome of an o b s e r v a t i o n would be : whether the o p e r a t o r i s working or i d l e and then the observer would t a l l y the r e s u l t s . T h i s t a l l y i s shown i n the f o l l o w i n g f i g u r e . , 20 TALLY I 1 NUMBER J / / / / //// / / / / / / / / ////I I//// / / / / / / / / / / / / ////I WORKING I//// / / / / / / / / / / / / / / / / | I//// / / / / / / / / / / / / ////I 98 I IDLE |//// /// TOTAL | 1 1 I I I 105 . i PEE CENT 93.33 6.67 100.00 Figu r e 3.1 Work Sampling T a l l y of Working and I d l e Time. The percentages of the t a l l i e s under working and i d l e c l a s s i f i c a t i o n s are estimates o f the a c t u a l percentage of time t h a t the worker was working and i d l e . Herein l i e s the fundamental p r i n c i p l e behind work sampling : "The number of o b s e r v a t i o n s i s p r o p o r t i o n a l t o the amount of time spent i n the working or i d l e s t a t e . " 1 3.3 CONFIDENCE LEVEL. The s t a t i s t i c a l p r i n c i p l e s of work sampling depend upon the bino m i a l d i s t r i b u t i o n as the outcome of an o b s e r v a t i o n i s e i t h e r working or i d l e ; success c r f a i l u r e . i B u f f a E. : MODERN PRODUCTION MANAGEMENT, New York, John Wiley £ sons, 1973 p. 431. 21 Such d i s t r i b u t i o n i s i d e n t i f i e d by: p = X = -NUMBER OBSERVED IN CLASSIFICATION (3.1) N TOTAL NUMBER OF OBSERVATIONS And p = P o r t i o n of time t h a t the worker was found working. Sigma = Standard D e v i a t i o n I t i s necessary t o determine what l e v e l of con f i d e n c e i s d e s i r e d i n the f i n a l r e s u l t s . The most common conf i d e n c e i n t e r v a l i s 95.45$, which i s u s u a l l y rounded o f f to 95%, T h i s concept can be v i s u a l i z e d as the area under a normal d i s t r i b u t i o n w i t h i n the l i m i t s + 2 Sigma . (3. 2) Where N = T o t a l Number of Observations -2Sigma •2Sigma F i g u r e 3.2 22 3 . 4 flCCDBACY Of 8QBK SAMPLING The accuracy achieved i n work sampling i s a f f e c t e d by the number of o b s e r v a t i o n s . The purpose of the study w i l l determine the number of o b s e r v a t i o n s r e g u i r e d . The a n a l y s t can always estimate the number of o b s e r v a t i o n s from previous experiences or from a p i l o t study. One o f the t h i n g s the a n a l y s t must always keep i n mind i s the i n h e r e n t v a r i a b i l i t y of the people, machines or processes being measured. In some cases the output of a department may present an i d e a l s i t u a t i o n f o r work sampling with raw m a t e r i a l of reasonably uniform g u a l i t y , low l a b o r t u r n o v e r , and good s u p e r v i s i o n . St other times the s i t u a t i o n may not be as f a v o r a b l e , and i n such cases the experience of the a n a l y s t p l a y s an important r o l e i n the study. For many kinds of measurements an accuracy of ±5% i s c o n s i d e r e d s a t i s f a c t o r y . Assuming t h a t the bin o m i a l d i s t r i b u t i o n i s used as a b a s i s f o r determining the e r r o r , the number of ob s e r v a t i o n s r e g u i r e d f o r 955S of confidence can be found t a k i n g ± 2 sigma : 2 3 Sp = 2 I y p ( 1 - p ) / S ] 4 3 . 3 ) Where : S = r e l a t i v e accuracy (• 5%) p = percentage occurrence o f an a c t i v i t y N = t o t a l number of random ob s e r v a t i o n s The r e l a t i v e accuracy i s a term commonly used i n i n d u s t r y , and i s d e f i n e d as the r a t i o of standard d e v i a t i o n t o the number of readings. From t h i s e x p r e s s i o n , i t i s c l e a r t h a t even i f the d e s i r e d accuracy i s known, there are two v a r i a b l e s : p, the percentage occurrence, and N, the t o t a l number of random o b s e r v a t i o n s . In order to f i n d N, p i s g e n e r a l l y assumed or estimated from a p i l o t study. 3 . 5 EXAMPLE O F ACCURACY Suppose se want to determine the percentage of p r o d u c t i v e time of a worker i n the department of l a t c h assembly by work sampling. Suppose that 105 o b s e r v a t i o n s were taken at random times, and t h a t 7 times the operator was e i t h e r i d l e c r out of the working area. Then the percentage of the productive time would be 9 3 . 3 3 % (98 / 1 0 5 x 1 0 0 = 9 3 . 3 3 $ ) And now N can be c a l c u l a t e d , knowing t h a t p = . 9 3 3 and S = • . 0 5 . 24 N .05p = 2 [ N .002 5p2 p <3.4) In t h i s case N = 1600 (1-.933) = 115 Observations .933 3.6 ACCURACY.fOB_A GIVEN NUHBEB OF 0 BS EB V A TIP N 5. In p r a c t i c e , the work sampling man covers s e v e r a l s t a t i o n s during h i s study, and most l i k e l y the percentages w i l l not be the same for the d i f f e r e n t s t a t i o n s . The previous equation can be s o l v e d f o r the r e l a t i v e accuracy S, given the percentage p and the t o t a l number of o b s e r v a t i o n s N. C o n t i n u i n g with the above example where p = 93.3% and N = 105. S= • .052 In t h i s case , i t c o u l d be s a i d t h a t we are 35% c o n f i d e n t t h a t the op e r a t o r under o b s e r v a t i o n i n the latch-assembly area was working 93.3% o f the time w i t h i n an accuracy of our estimate of • 5.2% of 93.3% V N 25 { 5.2% x 93.3% - 4.87% ), o r the t r u e value was between 98.17% and 88.4311, having as a most probable value 93.3%. 3.7 DETERMINISG PRODUCTION STANDARDS. Having found an estimate f o r the p r o p o r t i o n of time t h a t the worker spent doing p r o d u c t i v e a c t i v i t y , the f o l l o w i n g step i s t o compute the normal time. In doing so, the t o t a l time o f the study i n minutes i s r e g u i r e d . T h i s time e x c l u d e s scheduled d e l a y s such as c o f f e e breaks, lunch time and clean-up time. L e t us say t h a t the 105 o b s e r v a t i o n s were made during a day . There i s a 15 minute c o f f e e - b r e a k i n the morning and a 12 minute c o f f e e - b r e a k i n the afte r n o o n . Lunch takes 30 min and clean-up time i s 5 min. , Adding up a l l these scheduled d e l a y s , i t comes cut t o : F i r s t Coffee-Break 15 min. Lunch Time 30 min Second Coffee-Break 12 min Clean-up Time • 5 min. T o t a l Scheduled Delays 62 min. Working hours are from 7:30 t o 16:00 . That means workers spend 8.50 hours or 510 minutes i n the f a c t o r y . 26 S u b t r a c t i n g the scheduled delays (62 min.) from the time the worker spends i n the f a c t o r y (510 min.) gi v e s us the t o t a l a v a i l a b l e time f o r production which i s 510 - 62 = 448 rain. Another f a c t o r r e g u i r e d i n our computation i s the average r a t i n g . In t h i s case, the average performance r a t i n g was 10255, t h a t means t h a t f o r the a n a l y s t , the worker under o b s e r v a t i o n was performing s l i g h t l y above normal performance. F i n a l l y the output from t h i s bench was 855 l a t c h e s f o r the day. With t h i s i n f o r m a t i o n , the normal time i s computed from the f o l l o w i n g e x p r e s s i o n : (3.5) TOTAL TIME PRODUCTIVE AVERAGE OF STUDY X PERCENTAGE X PERFORMANCE NORMAL TIME = IN MINUTES FROM W.S. RATING TOTAL NUMBER OF PIECES PRODUCED Applying t h i s e g uation to the data mentioned above: (Time) (Percentage) (Rating) Normal time = 448 x .933 x 1.02 855 (Output) Normal time = .50 Min 27 The standard time i s c a l c u l a t e d from the n e r v a l time and the allowances f o r d e l a y s , f a t i g u e , and per s o n a l time. In t h i s department such allowances are 15%. P l a c i n g these numbers i n the f o l l o w i n g e x p r e s s i o n ; STANDARD TIME = (NORMAL TIME)X{1 + ALLOWANCES) (3.6) I t r e s u l t s : Standard time = |.50)x{1+ .15) Standard time = 0.57 min/latch Some manufacturing i n d u s t r i e s express t h e i r standards i n terms of pieces/hour f o r accounting purposes. In t h i s case the output r a t e i s : (60min/hour)* (0.57min/latch) = 104 l a t c h e s / h o u r . 28 C H API JB_IV APPLICATIONS OF COMPPTEBS TO-WORK SAoPLING 4.1 INTRODUCTION The work sampling s t u d i e s which are t h e s u b j e c t of t h i s t h e s i s were c a r r i e d out i n a l o c a l manufacturing p l a n t , whose main products are domestic and s e c u r i t y l o c k s . Some of the c o n s t i t u e n t p a r t s of the lock are made i n the l o c k company, other parts are s u p p l i e d by l o c a l f i r m s and the r e s t come from branch p l a n t s , which are spread a l l over the world. The work sampling s t u d i e s were done with the t o t a l c o o p e r a t i o n of the personnel of the company, from the General Manager, the I n d u s t r i a l E n g i n e e r i n g department, to the workers, who v o l u n t a r i l y agreed t o take an a c t i v e p a r t i n t h i s study. The study presented i n t h i s chapter was done i n the packing department. In t h i s department the p a r t s are s u p p l i e d by i n d i r e c t l a b o u r to the packing l i n e which i s attended by f o u r o p e r a t o r s . 2 9 4. 2 DESCRIPTION OF TBE..LINE A diagram of the l i n e i s found i n F i g . 4.1. In the f i r s t s t a t i o n ( F i g . 4.2), the o p e r a t o r opens the box i n batches o f ten or f i f t e e n and p l a c e s them on a moving b e l t . The same operator ( F i g . 4.3) i s i n charge of i n s e r t i n g a s m a l l p i e c e ( s t r i k e ) b e f o r e the boxes a r r i v e at the next s t a t i o n . The next operator gets the p a r t s from an overhead conveyor i n s e t s o f two wooden boxes. She takes the outer t r i m from one of the wooden boxes, the i n n e r t r i m from the other ( F i g . ,4.4A), puts them together ( F i g . 4.*}B) and places them i n the box ( F i g . 4.4C) . The t h i r d operator ( F i g . 4.5) i n s e r t s the l a t c h and screw package and c l o s e s the box. The l a s t operator ( F i g s . 4.6 and 4.7) i s i n charge of opening and f i l l i n g the s h i p p i n g cases. These f o u r o p e r a t o r s do not remain doing the same a c t i v i t y a l l the time, but they change t h e i r p l a c e s i n order to achieve a b e t t e r balance. 30 Operator 2 Assemble trims and place them in box. Operator 1 Open box insert strike 3' 9.5' Operator 3 Insert latch fe 9' Operator 4 Open and f i l l shipping cases fe 0 50' The numbers denote the operators DIAGRAM OF THE Figure P A C K I N G L I N E 31 The a c t i v i t y codes w i l l be d e s c r i b e d i n the f o l l o w i n g s e c t i o n s . They are presented here f o r convenience. These a c t i v i t i e s are i l l u s t r a t e d i n the f o l l o w i n g s e t of p i c t u r e s . » . - Open or make box. a c t i v i t y Code 11 F i g u r e 4.2 Place p a r t s i n box. A c t i v i t y Code 12 F i g u r e 4.3 32 33 • . - I n s e r t l a t c h . s .- Cl o s e the box. A c t i v i t y Code 12 A c t i v i t y Code 14 F i g u r e 4.5 Figure 4.6 34 F i g u r e 4.7 5 open or f i l l s h i p p i n g c a s e s , p l a c e then cn b e l t . A c t i v i t y Code 15. * Beaove empty boxes, 7 Walking from s t a t i o n s prepare m a t e r i a l . A c t i v i t y Code 22 A c t i v i t y Code 21. F i g u r e 4.9 Fi g u r e 4.8 35 4.3 THE STUDY As a f i r s t a t t e m p t , a s t a n d a r d w ork s a m p l i n g f o r m d e p i c t e d i n F i g . 3.1 was u s e d . D u r i n g t h e s t u d y , i t was f e l t t h a t a r e f i n e m e n t i n t h e f o r m o f p r e s e n t a t i o n o f t h e i n f o r m a t i o n was h i g h l y d e s i r a b l e , s i n c e i t w o u l d n o t o n l y show w h e t h e r t h e o p e r a t o r i s w o r k i n g o r i d l e , b u t i t w o u l d a l s o c l a s s i f y t h e w o r k i n g o r i d l e a c t i v i t y . * T h i s was p a r t i c u l a r l y a p p l i c a b l e t o t h e p a c k i n g l i n e , s i n c e t h e r e was a l o t o f w a l k i n g i n v o l v e d b e t w e e n s t a t i o n s . , I n o r d e r t o c l a s s i f y a l l a c t i v i t i e s t h a t a n y o f t h e f o u r w o r k e r s c o u l d be f o u n d p e r f o r m i n g , t h e l i n e was o b s e r v e d d u r i n g t h e p a c k i n g o f a l o c k c a l l e d A - 1 5 1 . The a c t i v i t i e s were d i v i d e d a s f o l l o w s . 1 T h i s f o r m i s f o u n d i n A p p e n d i x B. 36 *. - Open box. 2 . - I n s e r t s t r i k e . 3 . - Assemble outer and i n n e r t r i m , W p l a c e them i n box. 0 I n s e r t l a t c h R 5 . - F i l l s h i p p i n g case. K c l o s e box. I Prepare m a t e r i a l , N remove empty boxes. G 7 . - Walk from s t a t i o n s . a . - Wait f o r p a r t s . I Pick up p a r t s from f l o o r . ,. D Out of working area. L 1 *. - Converse. E Table 4.1 C l a s s i f i c a t i o n of a c t i v i t i e s . In t h i s c a s e , there are 11 d i f f e r e n t a c t i v i t i e s which can be c l a s s i f i e d as pr o d u c t i v e or non- pr o d u c t i v e . A c t i v i t i e s 1 to 7 r e p r e s e n t the working a c t i v i t y , whereas a c t i v i t i e s 8 t c 11 are non-working. I t must be noted t h a t •walking* was co n s i d e r e d to be productive s i n c e i t was a necessary a c t i v i t y i n the l i n e . I t i s customary i n t h i s kind o f study, t o use a t a b l e of random numbers c r random times. In t h i s p r e l i m i n a r y study, a programme was w r i t t e n f o r a 37 Hewlett Packard C a l c u l a t o r t h a t generates random times between working hours e x c l u d i n g scheduled d e l a y s (coffee-breaks and l u n c h t i m e ) 1 . A p i l o t work sampling study was c a r r i e d out u s i n g the improved r e c o r d i n g forms and the random times generated by a programmable c a l c u l a t o r . The o p e r a t o r s were observed s e g u e n t i a l l y . The operator i n F i g . 4.2 was f i r s t , the operator i n F i g . 4.3 was second, the o p e r a t o r i n F i g . 4.4 was t h i r d and f i n a l l y the operator i n F i g . 4.5 was f o u r t h . I t must be noted t h a t the sequence r e f e r s t o the o p e r a t o r s , not to the s t a t i o n s , s i n c e as i t was s t a t e d b e f o r e , the o p e r a t o r s did not remain a t a f i x e d p o s i t i o n . The r e s u l t s from t h i s p r e l i m i n a r y study are as f o l l o w s . 1 The programme and a sample sheet f o r r e c o r d i n g the random times f o r o b s e r v a t i o n s are found i n Appendix E 38 ACTIVITY NO. OF PERCENTAGE ACCUMULATIVE OBSERVATIONS PERCENTAGE 1 Open box. 9 8.1 8. 1 2 I n s e r t s t r i k e . 6 5.4 13.5 3 Assemble t r i m s 8 place i n box. 36 32.4 45.9 * I n s e r t l a t c h , screw packs. 7 6.3 52.3 s F i l l s h i p p i n g case, c l o s e box. 21 18.9 71.2 6 Prepare m a t e r i a l , remove empty boxes. 2 1.8 73.0 7 Walk. 13 11.7 84.7 HOBKING TOTAL. 94 84.7 » Wait f o r p a r t s . 0 0.0 0.0 9 Pick up p a r t s from the f l o o r . 2 1.8 1.8 »o out of area. 13 11.7 13.5 i i Converse. 2 1.8 15.3 IDLE TOTAL. 17 15.3 Table 4.2 P r e l i m i n a r y study o f the packing l i n e . .,- The t o t a l number of o b s e r v a t i o n s was 111., The output d u r i n g the study was 82 s h i p p i n g cases. Each s h i p p i n g case c o n t a i n s 24 l o c k s , so the output was 1968 l o c k s . 39 The t o t a l length of the study was 2 hr. 31 min. or 151 min. Note the high percentage of t o t a l o b s e r v a t i o n s t h a t r e p r e s e n t s a c t i v i t y 7, *Walking*. The study c o u l d be f u r t h e r d i v i d e d i n t o 'walking* and 'not-walking*. T h i s new c l a s s i f i c a t i o n a l l o w s us t o apply the p r i n c i p l e of the b i n o m i a l d i s t r i b u t i o n (see Chapter 3) and to s e t p r o b a b i l i t y l i m i t s i n our f i n d i n g s . The same reasoning c o u l d be a p p l i e d to each a c t i v i t y . The o p e r a t o r s were not r a t e d during the study. They were considered t o be working a t a normal pace. The number of readings r e q u i r e d f o r + 5% i s computed from Eq. 3.6 N« = 1600 x (1 - . 647)/.847 N* = 2 89 Observations. Hore o b s e r v a t i o n s were taken to s a t i s f y the above c o n d i t i c n , o b t a i n i n q the 'following values : Percentage = .870 Output = 223 Shipping cases = 5352 l o c k s . Time of study = 400 min. By a p p l y i n g Eg. 3.7 and t a k i n g r a t i n g equals t o 100%, we o b t a i n : Normal time = 400 min. x .870 / 5352 l o c k s Normal time = .06 min./lock or 923 l o c k s / h r . The p e r s o n a l and f a t i g u e allowances f o r t h i s department are 15 %. By a p p l y i n g Eg. 3.8, the standard time i s : 40 Standard time = (.06) x (1 + .15} = .07 min. / l o c k , or Standard output — 802 l o c k s / h r . T h i s standard i s f o r the packing c f the l o c k A-151 when the l i n e i s attended by f o u r workers. The r e l a t i v e accuracy i s found using Eg. 3.5 S = { 2 / .870 } x { y .870 x (1 - .847) /295 } S = ± 4.5 f o r 95% c e r t a i n t y . During the study, the a n a l y s t observed the d i f f e r e n t paces of the workers, and found t h a t the improved form f o r r e c o r d i n g the i n f o r m a t i o n was i n a p p r o p r i a t e f o r keeping t r a c k of these v a r i a t i o n s 1 . Moreover, i t was noted t h a t the operators* paces were not c o n s i s t e n t . 4.4 BATING IS BOBK SAMPLING. A d i f f e r e n t procedure f o r r e c o r d i n g the o b s e r v a t i o n s had to be devised i n order to i n c l u d e the r a t i n g f a c t o r . , Two r e c o r d s were r e q u i r e d f o r each a c t i v i t y c l a s s i f i e d as working (see Table 4.1). One f o r the number of o b s e r v a t i o n s and another f o r the r a t i n g . For a c t i v i t i e s c l a s s i f i e d as ' I d l e * , o n l y a r e c o r d f o r the number of o b s e r v a t i o n s was needed. 1 See form i n Appendix B 11 To i l l u s t r a t e t h i s , suppose t h a t the a n a l y s t recorded the f o l l o w i n g r a t i n g s while observing a worker performing the a c t i v i t y number S, FILLING SHIPPING CASES AND CLOSING BOXES (see Table 4.1). 90 90 100 90 80 100 90 80 100 90 110 110 90 90 110 100 110 90 100 110 90 The number of o b s e r v a t i o n s was 21, which r e p r e s e n t s 18.9 % o f the t o t a l o b s e r v a t i o n s . The average r a t i n g would be the sum of the r a t i n g s d i v i d e d by the number of o b s e r v a t i o n s i n t h i s category. AVERAGE RATING = I!RATINGS/NO. RATED OBSERVATIONS (4.1) In t h i s case AVERAGE RATING = 2021 / 21 = 96.2 The r a t e d percentage c o u l d be e a s i l y e v a l u a t e d from the f o l l o w i n g e x p r e s s i o n : RATED PERCENTAGE = AVERAGE RATING X PERCENTAGE (4.2) In the case of t h i s p r e l i m i n a r y study f o r a c t i v i t y 5, we have : Rated percentage = 96. 19/100 x 18.9 = 16.18 % At t h i s p o i n t i n time, i t was becoming s l i g h t l y d i f f i c u l t and t e d i o u s to keep separate r e c o r d s o f the a c t i v i t i e s and the r a t i n g s . Moreover, s i n c e work sampling was intended to be used i n d i f f e r e n t departments, new records f o r the job number and department number were r e g u i r e d . 42 A computer programme was thought t o be a s u i t a b l e s o l u t i o n f o r the manipulation and processing of the data, s i n c e b a s i c a l l y what we have here i s numerous rec o r d s t h a t can e a s i l y be t r a n s l a t e d i n t o a r r a y s . The computations themselves are f a i r l y s t r a i g h t f o r w a r d , 4.5 SCHMID'S COMPOTES PBOGEABflE. , Before launching i n t o the development of t h i s programme, a review of the p u b l i c a t i o n s i n t h i s f i e l d was c a r r i e d out. I t was found t h a t Schmid*s computer programme appeared t o be s i m i l a r and compatible with the i d e a s presented i n t h i s t h e s i s * . Schmid's computer programme i s one of the l a t e s t p u b l i c a t i o n s o f a high c a l i b e r i n work sampling. Thus, to avoid unnecessary r e p e t i t i o n , the use of t h i s programme seemed more l o g i c a l than the development of a new one. Except f o r t h e s l i g h t m o d i f i c a t i o n s and necessary a d a p t a t i o n s to the e x i s t i n g computing f a c i l i t i e s a t U.B.C. {because the programme was o r i g i n a l l y w r i t t e n f o r a Model 1130 Computer), t h i s programme remains as designed by Dr. Schmid. * Schmid fl. : WORK MEaSUREMENT SAMPLING, U n i v e r s i t y of Dayton, 1970. 43 For i d e n t i f i c a t i o n purposes. Dr. Schmid makes a f u r t h e r s u b d i v i s i o n of 'working*, t h a t i s production and p r o d u c t i o n - s u p p o r t . I d l e i s c a l l e d non-prod a c t i v e . P r o d u c t i v e a c t i v i t i e s are given codes s t a r t i n g with 11. Production-support a c t i v i t i e s b egin with 21, and non-productive a c t i v i t i e s s t a r t with 31. During the computations, the computer d i s t i n g u i s h e s only two major c a t e g o r i e s . A c t i v i t i e s whose numbers are l e s s than 30 are * working* and a c t i v i t i e s whose numbers are gre a t e r than 30 are ' i d l e * (see Table 4.3). The computer programme holds up t o 1000 o b s e r v a t i o n s i n a s i n g l e run . I t has s e v e r a l a r r a y s to keep t r a c k of the number of o b s e r v a t i o n s and the r a t i n g f o r each a c t i v i t y . I t a p p l i e s Eg. 4. 1 t o f i n d t h e average r a t i n g f o r each a c t i v i t y , then uses Eg. 4.2 to f i n d the r a t e d percentage. During the c a l c u l a t i o n s , the programme checks f o r non-productive a c t i v i t i e s (whose codes a r e g r e a t e r than 30). I f the search i s s u c c e s s f u l , t h a t a c t i v i t y i s r a t e d z e r o . The t o t a l r a t e d a c t i v i t y i s the sum of a l l r a t e d percentages. TOTAL RATED ACTIVITY = ZRATED PERCENTAGE 44.3) where : RATED PERCENTAGE = 0, f o r a c t i v i t y whose code i s gr e a t e r than 30. Th i s new c l a s s i f i c a t i o n i s shown on the f o l l o w i n g page. 44 DEPARTMENT 49 - PACKING ACTIVITY CODES A c t i v i t y S i g n i f i c a n c e Code No. Produc t i o n 11 Open or make box, put on l a b e l s . 12 P l a c e p a r t s i n box. 13 I n s e r t i n n e r and outer t r i m and pl a c e them i n box. 14 Cl o s e box or put on l i d , apply t r a n s p a r e n t tape. 15 Open or f i l l s h i p p i n g case, place i t on b e l t . P r o d u c t i o n support 21 Remove empty boxes, prepare m a t e r i a l . 22 walk. Non-productive 31 Wait f o r pa r t s or r e l e a s e stuck wooden boxes. . 32 P i c k up p a r t s from f l o o r . 33 Absent, personal time. 34 T a l k . Table 4.3 45 From the above t a b l e , i t can be seen t h a t the a c t i v i t y codes d e s c r i b e a l l p o s s i b l e a c t i v i t i e s t h a t the worker can be found performing. T h i s breaking down of the a c t i v i t i e s i n t o three major groups; ( p r o d u c t i o n , production support and non- productive) i s done by the a n a l y s t to achieve a b e t t e r understanding of the balance o f the assembly l i n e (in t h i s p a r t i c u l a r case packing l o c k s ) , s i n c e f o r c a l c u l a t i o n purposes, the computer t r e a t s a l l these 11 a c t i v i t i e s i n two major groups. One comprises a l l prod u c t i v e and production support a c t i v i t i e s , and the other i n c l u d e s non-productive a c t i v i t i e s . , T h i s c l a s s i f i c a t i o n i n t o two groups l e a d s us once more to having two c o n d i t i o n s as i n the case of t h e previous chapter (working or i d l e , success or f a i l u r e ) . That i s why, although t h e r e are 11 a c t i v i t i e s , the binomial d i s t r i b u t i o n i s s t i l l a p p l i c a b l e . T h i s computer programme has p r o v i s i o n s f o r keeping t r a c k of the times a t which o b s e r v a t i o n s are made. I t a l s o takes as input parameters the s t a r t i n g and f i n i s h i n g of the s h i f t times, and the s t a r t i n g and leng t h of the scheduled delays ( c o f f e e - b r e a k s and lunch time) . a i t h t h i s i n f o r m a t i o n , the e f f e c t i v e time of the study i s c a l c u l a t e d a c cording to the f o l l o w i n g e x p r e s s i o n : TOTAL TIME STUDY = LENGTH OF THE STUDY - SCHEDULED DELAYS (4.4) 46 F i n a l l y , knowing the number of pieces produced, the normal time i s c a l c u l a t e d by ap p l y i n g Eg. 3.7. I t must be noted t h a t the product of «PRODUCTIVE PERCENTAGE FROM H.S. X AVERAGE PERFORMANCE RATING' has been c a l l e d TOTAL RATED ACTIVITY (see Eg. 4.3), so t h i s eguation becomes TOTAL TIME TOTAL OF STUDY X RATED NORMAL TIME = IN MINUTES ACTIVITY (4. 5) TOTAL NUMBER OF PIECES PRODUCED The standard time i s found by a p p l y i n g Eg. 3.8. The computer programme has e i g h t more re c o r d s or a r r a y s . They are used f o r the department, o p e r a t o r , job, s p e c i a l , i n t e r r u p t i o n , day, s h i f t numbers, and the s i z e of the l o t . 4.6 RANDOM TIMES FOB OBSERVATIONS. Work sampling r e q u i r e s that each i n d i v i d u a l moment have an equal l i k e l i h o o d of beinq chosen. In order t o be s t a t i s t i c a l l y a c c e p t a b l e , the o b s e r v a t i o n s must be random, unbiased, and independent. A t a b l e o f random numbers i s commonly used i n t h i s type c f study to ensure the randomness of the times a t which the o b s e r v a t i o n s are made. 47 In t h i s paper, a computer programme was developed to generate random times during working hours e x c l u d i n g scheduled d e l a y s . T h i s programme uses a f u n c t i o n c a l l e d RAND f o r g e n e r a t i n g random numbers. RAND i s a f u n c t i o n sufcprogramme w r i t t e n i n /360 assembly language and c a l l a b l e from FORTRAN. T h i s subroutine generates random numbers X, such as 0<X<1 under uniform d i s t r i b u t i o n . I t has a p e r i o d of 2 3 0 , and has proved to meet the s t o c h a s t i c properties.++• The random times are p r i n t e d out i n a format s u i t a b l e f o r r e c o r d i n g the o b s e r v a t i o n s . T h i s programme and a run f o r two p o s i t i o n s or s t a t i o n s are d e p i c t e d i n Appendix D. From the o b s e r v a t i o n sheet (see Appendix D), the e i g h t a r r a y s t h a t were mentioned i n the pre v i o u s s e c t i o n are as f o l l o w : PEP Nun stands f o r department number, CPR NOB, stands f o r operator or worker number. JOB MOMBER aeans the piece number or the assembly number. The SP E C i a l and INTESruption codes are used when the operator stops or s t a r t s a p a r t i c u l a r job. They are a l s o used when the operator s h i f t s h i s p o s i t i o n . These numbers are seldom used. ++• See "UBC RANDOM" Hrite-Op, A p r i l 1975 48 For the worker, A c t i v i t y Code and P r o d u c t i o n RaTe were d e s c r i b e d i n previous s e c t i o n s of t h i s chapter, DAY-NOMber s h a l l be used t o keep t r a c k c f the le n g t h of the study. The SHIFT number was 1 f o r a l l cases i n t h i s paper, and the LOT-SIZe has to be posted only once. 4.7 A PRACTICAL APPLICATION OF SCBflID«S PROGRAMME Using o b s e r v a t i o n sheets l i k e the ones mentioned above, a p i l o t work sampling study was c a r r i e d out on the b e l t . I n t h i s c a s e , the ob s e r v a t i o n s were taken when the o p e r a t o r s were packing l o c k s type A-151. The o b s e r v a t i o n s are shown i n the f o l l o w i n g t h r e e pages. 49 J IDENTIFICATION I | |DEP|OPH| JOB HE|MN|SC|NOMJNUMj NUMBER I I I i 1 | L | TIME I I I I N | I E | I S l I t WORKER t |S| | |P|N| | |DAY|Hj LOT| |E|T|A CJP RTJMUHIIJSIZJ PAGE NO.1 I C | B | I I 1 13 42 30 49 44 8 1 2 13 47 50 49 44 151 21 1 3 13 50 0 49 44 151 21 1 4 13 59 30 49 44 151 15 110 1 5 14 2 40 49 44 151 34 1 6 14 3 40 4S 44 151 14 1 7 14 4 50 49 44 151 14 070 1 8 14 5 20 49 44 151 33 1 9 14 6 10 49 44 151 14 085 1 10 14 6 50 49 44 151 33 1 11 14 7 0 49 44 151 14 085 1 12 14 8 30 49 44 151 34 1 13 14 9 0 49 44 151 13 090 1 14 14 10 40 49 44 151 14 1 15 14 11 50 49 44 151 14 075 1 16 14 12 0 49 44 151 14 110 1 17 14 12 10 49 44 151 13 095 1 18 14 12 20 49 44 151 33 1 19 14 12 40 49 44 151 14 080 1 20 14 15 10 49 44 151 15 110 1 21 14 15 30 49 44 151 11 1 22 14 16 10 49 44 151 14 070 1 23 14 20 20 49 44 151 14 070 1 24 14 21 0 49 44 151 14 110 1 25 14 22 50 49 44 151 13 095 1 26 14 24 0 49 44 151 14 095 1 27 14 29 10 49 44 151 14 075 1 28 14 29 20 49 44 151 33 1 29 14 50 20 49 44 151 14 095 1 30 14 52 50 49 44 151 14 080 1 31 14 55 0 49 44 151 33 1 32 14 56 30 49 44 151 15 105 1 33 14 58 20 49 44 151 31 1 34 15 2 40 49 44 151 31 1 35 15 5 20 49 44 151 33 1 36 15 6 20 49 44 151 13 095 1 37 15 8 10 49 44 151 14 095 1 38 15 8 20 49 44 151 14 090 1 39 15 9 30 49 44 151 33 1 40 15 12 10 49 44 151 13 095 1 41 15 12 50 49 44 151 14 090 1 42 15 13 20 49 44 151 21 1 43 15 14 30 49 44 151 33 1 44 15 15 0 49 44 151 9 11 110 1 |F| .121. 40 Table 4.4 - A 50 I I | TIME £ IDENTIFICATION |S| I| WORKER j | Sj | 1 I I 1 I IDEPJOPRJ JOB i p i m i |DAY|H|LOT, 1 N |HR|MN|SCJNUMJNUM| NUMBER IE|T|A C|P RTJ NUM111SIZ\ 1 E I 1 I I I 1 1C | E1 | f 1 — .1 J L_ I J L _1_ J ISJ | ....... j z m i 45 7 51 30 49 44 8 3 1 46 7 53 30 49 44 151 14 080 3 1 47 7 54 30 49 44 151 14 3 1 48 7 54 50 49 44 151 15 3 1 49 7 55 20 49 44 151 12 3 1 50 7 57 10 49 44 151 14 090 3 1 51 7 57 40 49 44 151 13 3 1 52 7 58 10 49 44 151 33 3 1 53 7 59 0 49 44 151 14 080 3 1 54 7 59 20 49 44 151 14 075 3 1 55 8 3 30 49 44 151 14 090 3 1 56 8 4 0 40 44 151 14 3 1 57 8 4 30 49 44 151 14 095 3 1 58 8 7 10 49 44 151 14 3 1 59 8 8 20 49 44 151 34 3 1 60 8 8 30 49 44 151 32 3 1 61 8 8 40 49 44 151 14 090 3 1 62 8 11 30 49 44 151 13 3 1 63 8 11 50 49 44 151 14 095 3 1 64 8 13 10 49 44 151 11 095 3 1 65 8 13 30 49 44 151 14 090 3 1 66 8 15 30 49 44 151 13 3 1 67 8 17 30 49 44 151 14 095 3 1 68 8 18 20 49 44 151 11 095 3 1 69 8 19 20 49 44 151 14 090 3 1 70 8 20 20 49 44 151 14 3 1 71 8 20 40 49 44 151 33 3 1 72 8 21 0 49 44 151 12 090 3 1 73 8 21 10 49 44 151 14 095 3 1 74 8 21 30 49 44 151 13 080 3 1 75 8 21 40 49 44 151 33 3 1 77 8 22 30 49 44 151 14 090 3 1 78 8 24 30 49 44 151 13 090 3 1 79 8 31 10 49 44 151 14 105 3 1 80 8 33 0 49 44 151 13 090 3 1 81 8 34 0 49 44 151 34 3 1 82 8 35 10 49 44 151 13 3 1 83 8 38 0 49 44 151 11 095 3 1 84 8 38 10 49 44 151 13 095 3 1 85 8 38 50 49 44 151 33 3 1 86 8 39 50 49 44 151 15 3 1 87 8 41 50 49 44 151 14 095 3 1 88 8 47 30 49 44 151 14 095 3 1 Table 4.4 - B 51 I I | TIKE J IDENTIIICiTION_ | I | T I |DEP|QPBJ JOB | N |HR|I9N|SC| NUM| N0H| NUMBER I £ I I I I I I l _ _ _ J L _ l _ _ J _ _ J 1 _ „ 1 _ „ _ m i l WORKER I | SI | |P|M| | |DAY|H|LOTJ |E|T|A C|P BT|NOM|I|SIZ| IC i B| J | |E| | I >B> L J i l l \ 89 8 48 0 49 44 151 14 095 3 90 8 50 30 49 44 151 34 3 91 8 55 30 49 44 151 14 095 3 92 8 56 0 49 44 151 14 095 3 93 8 56 3 0 49 44 151 14 090 3 94 8 57 30 49 44 151 14 3 95 8 58 40 49 44 151 34 3 96 9 0 40 49 44 151 31 3 97 9 2 29 49 44 151 31 3 98 9 2 50 49 44 151 31 3 99 9 5 10 49 44 151 34 3 100 9 5 20 49 44 151 31 3 101 9 9 0 49 44 9 3 4 2 PAGE NO. 3 » » > » » > END CF FILE Table 4.4 - C 52 Each o b s e r v a t i o n r e p r e s e n t s a computing c a r d . T h i s data was submitted to an IBM 360 computer, g i v i n g the f o l l o w i n g r e s u l t s : JOB N P S STD. TIME STD. OUTPUT NUMBER {MIN.) (PABTS/HOUB) 151 42 80. 6% ±15% .075 803 151 55 80.6% ±13$ .068 877 TOTAL 97 80.6% ±10% .071 839 THEBE HEBE FOUR OPERATORS ATTENDING THE LINE. Table 4.5 Where : N - Number o f r e a d i n g s . P = Percentage of time the worker spent working. S = R e l a t i v e accuracy. The p i l o t study proved to be s a t i s f a c t o r y as f a r as the methodology was concerned., I t took the a n a l y s t a sh o r t time t o get used t o t h e forms and a l s o to r e l a t e a c t i v i t i e s to codes. More work sampling s t u d i e s were done i n the packing l i n e using the same a c t i v i t y codes a l r e a d y d e s c r i b e d . 53 The r e s u l t s are summarized i n the f o l l o w i n g t a b l e : JOB NUMBER 01301020 11017002 11030100 1 103 3102 N 244 168 55 47 9 3.2% 92. 4% 87.3% 94.8% ±3.5% ±4.4% ±10.3% ±6.8% STD, OUTPUT (PARTS/HOUR) 247 179 ** 488 644 THE LINE WAS ATTENDED BY THREE WORKERS. Table 4.6 At t h i s p o i n t i n time, i t became important t o f i n d out the e f f e c t of r a t i n g i n the e v a l u a t i o n of the standard. Table 4.7 shows a comparison between the standard c a l c u l a t e d i n c l u d i n g and i g n o r i n g the r a t i n g f a c t o r . JOB NUMBER 01301020 11017002 11030100 11033102 STD. CALCULATED WITHOUT HATING (LOCKS/HOUR) 237 172 478 652 STD. CALCULATED RATIO WITH BATING (LCCKS/HCUR) 247 .960 179 .961 488 .980 644 1.012 Table 4.7 ** An e x t r a worker j o i n e d the crew h a l f way through the study. 54 According to the r e s u l t s presented i n Table 4.7, we can conclude t h a t the r a t i n g f a c t o r i s important i n the s e t t i n g of standards by work sampling. A l l these work sampling s t u d i e s were c o n c u r r e n t l y c a r r i e d out with an ongoing stop-watch study programme. 4.8 BESPITS FBOM STOP-WATCH STUDIES Making use of the data c o l l e c t e d by the personnel of the I n d u s t r i a l E n g i n e e r i n g department o f the l o c a l l o c k f a c t o r y , the f o l l o w i n g r e s u l t s were obtained. JOB STANDARD SET BY ACTUAL STANDARD SET EY NUMBER *W0BK SAMPLING *0UTP0T* *TIME STUDY 11017002 51 54 75 11030100 163 143 182 Table 4.8 The above f i g u r e shows that the standards s e t by means of work sampling were c l o s e r t o the a c t u a l output r e p o r t e d by the foreman of the packing l i n e , 2 * T h i s standard i s measured i n Locks/Hour/iorker f o r accounting purposes. 1 Eased on the average over a p e r i o d of a month. 2 T h i s p o i n t w i l l be d i s c u s s e d i n the c o n c l u s i o n s . 55 4.9 TIME R EOHIBED TO SET TEE STANDARD TIME Table 4.9 shows the break down of an estimate of the time needed f o r an a n a l y s t t o s e t standards f o l l o w i n g the two methods mentioned i n t h i s paper. TIME STUDY 1 HOURS Break down of the elements i n t o components .25 Taking the readings 2.50 C a r r y i n g out computations 1.00 TOTAL 3.75 WORK SAMPLING2 HOURS E s t a b l i s h i n g a c t i v i t y codes .25 Taking the r e a d i n g s 5.00 C a r r y i n g out computations 3 .25 TOTAL 5.50 Table 4.9 1 T h i s estimate i s an a p p r a i s a l from the personnel of the I n d u s t r i a l E n g i n e e r i n g based on t h e i r time s t u d i e s . 2 Based on r e c o r d s kept d u r i n g the p r e p a r a t i o n of t h i s paper. 3 A c t u a l l y , r e q u i r e d time t o prepare and punch the data, s i n c e the computations themselves are c a r r i e d out by an IBM computer. 56 4.10 SUMMARY OF THIS CHAPTER From the s t u d i e s presented i n t h i s c h a p t e r , the f o l l o w i n g c o n c l u s i o n s were drawn : 1. - Work sampling i s a p p l i c a b l e to an assembly l i n e o p e r a t i o n . 2. - The r a t i n g f a c t o r seemed t o be s i g n i f i c a n t i n f i x i n g the standard time by means of work sampling. 3. - The time r e q u i r e d t o s e t standards was higher using work sampling than using time study. 57 CHAPTER V WORK SAMPLING APPLIED TO A SHORT CYCLE OPERATION In t h i s c h a p t e r , a study c a r r i e d cut i n the Latch Assembly Department i s d e s c r i b e d . A b r i e f e x p l a n a t i o n of how the readings are recorded d u r i n g a work sampling study i s a l s o given. A l a t c h i s an important c o n s t i t u e n t of a l o c k . In t h i s f a c t o r y , t h e r e are b a s i c a l l y two types of l a t c h e s . One of them i s used i n bedroom doors. The other one i s found i n house entrances or i n some other p l a c e s where more s e c u r i t y i s needed (see Appendix E). 5.1 W ORf_SAMPLING IN DEPARTMENT 4 1 LATCH-ASSEMBLY F i r s t of a l l , the a n a l y s t must understand the mechanics of the assembly, i t s d i f f i c u l t i e s and p e c u l i a r i t i e s . At t h i s stage the a n a l y s t would have to decide the pace or tempo t h a t c o n s t i t u t e s a normal performance. E q u a l l y important i s the e s t a b l i s h m e n t of a c t i v i t y codes. F i g s . 5.1 to 5.3 i l l u s t r a t e some of the wcrker*s a c t i v i t i e s and the working place. v In t h i s case, the p a r t s f o r the assembly are s u p p l i e d by i n d i r e c t labour. I t must be noted t h a t the worker has a l l the p i e c e s at hand and they are w e l l organized; t h e r e f o r e a high percentage of p r o d u c t i o n • production support i s expected. 58 11.- Normal Production 21.- Testing latches Figure 5.1 Figure 5.2 This i s the working place, a s e l f staking bench Figure 5.3 Table 5.1 shows the a c t i v i t y codes f o r t h i s study. 59 DEPABTMENT 41 - LATCH-ASSEBBLY ACTIVITY CODES A c t i v i t y S i g n i f i c a n c e Code No. Produ c t i o n 11 Normal production. Assembly of p a r t s . Production Suppprt 21 T e s t i n g l a t c h e s , 22 Changing boxes. 23 R e p a i r i n g assembly or d e f e c t i v e p a r t s . 24 Unavoidable Delays: m a t e r i a l i s s u p p l i e d t o the bench, r e c e i v i n g i n s t r u c t i o n s , r e c o r d i n g p r o d u c t i o n . Non-productive 31 Avoidable Delays: i d l e , t a l k i n g 32 Absent. 33 Clean-up Table 5.1 60 In t h i s case, the department number i s 41, the operator number i s the same as the bench number, and the job number i s the assembly number at the time of o b s e r v a t i o n . Since the s t a t i o n s are f a i r l y c l o s e t o each other, the a n a l y s t was able t o observe e i g h t benches i n the same day*s study, t a k i n g 105 readings from each bench. The f o l l o w i n g p i c t u r e shows the g e n e r a l l a y o u t of t h i s department. Department 41 Latch Assembly Figure 5.4 The a n a l y s t gathered h i s data u s i n q o b s e r v a t i o n sheets d e s c r i b e d i n the previous chapter (page 46), and shewn i n Appendix D . The f o l l o w i n q page i s part of t h i s study. 61 L 1 TIME I IDENTIFICATION >|S|I|. WORKERI 1S 1 I | | | |DEP|OPR| JOB N |HR:MN:S|NUM|NUM| NUMBER E I | | | | | _ JL 1_ 1 J _ 1. 1 |P|N| |E|T|i |C|E| _1_JBL 1 \ C|P 1 I 1 RT | 1 1 DAY|H|LOT NU13|I | SIZ |F| ITI •< 1 11 7:38:41 41| 111 4 1 I \ 1 1 1 311 1 5 111 1 - _ 2 j _ 7 i _ U i 2 l _ __1. 1 1 I 1 1 1 I 111 I 111 1 J l _ 7 : 4 4 i 5 l I 1 • • • • 1 \ 1 1 i 11| 90 | 11 1 1 _1_7_ 49̂ .51 I - -1 _ _ 1 1 1 1 t 1 11| 1 „;',-1.11 .'-,.,• • I SI 7:55:1J[ I I 1 I 1 1 I I 111 I _11JL 1 ___l_8i_3i41 I - 1 -.- . , 1 1 1 I 1 1 11| I 111 1 71 8; 4;2| I . . 1 - . - .. 1 1 1 i I I 11| I HI 1 _ _JL__i _.0JL_ i _1 ' _ 1 I 1 1 I j 1 11 " - 1 111 1 Jl_8:12;0|. I 1 •. 1 1 1 1 I I 11| 105 | I _1_i__i1«:0| I ... 1 1 1 1 1 1 1 H i 1 _11J^ I 111 8__2:21 I .-. 1 1 1 1 1 I I 111 105| • 111- 1 - I _ l _ _ i 2 3 i 0 l _ - 1 • . I- - - 1 1 1 1 1 1 111 •: I •'i'-- HI 1 131 8:23:4| 1 „ r 1 • 1 1 1 1 1 1 111 I . .. n-i.:.,.,.. I 14j 8;25;5| 1 ..-.,J .. 1 I 1 I 1 1 321 1 . j 11 • • I _1_l_8l_1i31_ 1 1_i_8iJ2:3l_ __1. 1 _1__ . I 1 1 1 1 J_JL 1 1 i I 21| 1 in • — t.H,,;;':,,„;, I 171 8;33:0| 1 _ 1 1 1 1 1 1 1 211 1 11J - 1 _18l_8i38:3j 1. _1_ 1 1 1 1 1 1 211 I 111 1 19J 8:40:21 1 ••7,1 ,• ;. ; - 1 1 1 1 1 1 111 I 111_ 1 _201 8i4l£41 1 _JL _ _ • . 1 1 1 1 1 1 11| 1 : r .111 -„;., 1 2Jl_8i42i21_ 1 ; 1 I 1 1 1 111_ STATION NO. 1 PAGE NO.1 AUG,25,»77 COfiHEMTS Tafcle 5.2 62 Each l i n e from the o b s e r v a t i o n sheets i s punched i n t o an I B B computing c a r d . The v e r t i c a l l i n e means t h a t the i n f o r m a t i o n i s to be repeated from the previous c a r d . The l i s t i n g of the f i r s t ten cards of the previous page i s given i n Table 5 . 3 . c j T I M E | I D E N T I F I C A T I C N 1 s I| W O B K E J | f S I A ! 1 I ! D E P | O P B | J O B P N A C T J | D A Y | H ( L O T s H R J M N J S N0M|NUM| NUMBEB |E T C O D | B A T E | H 0 H | I | S I Z D t 1 I I C E 1 1 IEI — _ _ l _ l _ l I _ _ ! _ . ' — R .___ 1 _ _ _ _ 1. 121 _ _ _ 1 7 i 3 8 i 4 | _ i i i 1 __L11 _. 4 _ _ _ 3 J I _ . l _ 5 _ | 1 | _ _ _ _ 2 7 : 4 1 : 2 - 1 1 I _ _ _ 1 J _ _ _ _ _ _ _ — _ i i | _ ! _ _ _ i l i 3 _ _ _ _ _ _ _ _i» 11 1 1 | 4 _ _ 1 1 1 9 0 | _ 5 _ |_1 | _ — _ _ 4 _ l i _ _ _ . 5 i _ j . _ i _ i i i _ 4 i _ _ _JLJ. 1 _____ 1 _ 5 _ 1 JL! _ _ ___ 7 : 5 5 : 1 4 1 J 1 1 | n 1 _ _ 111 1 5 j 1 | _ _ 6 8 : 3 : 4 i - i i I_J_I_. 4 1 _ _ ' 1JL1 1 _____ 1 Jl 1 _ _ 2 8 : 4 ; 2 - J l i _ l l i _ 4 ,- - -- _ '_" _ _ _ ! 1 5 | 1 | _ _ 8 _ _ _ _ _ _ _ l _ _ J l l _ _ _ l _ . 4_ . 1 _ _JII i _ 5 _ m 9 8 : 1 2 : 0 411 111 . n 111 1 0 5 1 5 H i __10 _ _ i _ _ _ 0 1 411 111 4 - - -' •• _ _ U J l _ 5_ I J I T a b l e 5 . 3 Note that whenever the a n a l y s t r a t e s the operator at normal performance { 1 0 0 % ) , the r a t i n g i s l e f t blank. 63 A f t e r t he computing cards are checked and any mistakes by the a n a l y s t or the key-punch operator are c o r r e c t e d , the data i s submitted t o the computer. The computer reads t h i s data i n the f o l l o w i n g manner: c ! _TIME | IDENTIFICATION - S| I| |S| A | | |DP|OPR| JOE P N I ACT| DAY I Hi LOT R HR|MN|SC|NM|NUM| NUMBER E T COD RATE MUM I U S I Z B 1 I 1 i 1 Cj E |F'| — 1—_l—.1 — 1 — — 1 — - _ _ — 1 ___ __—_ I U _ 1 7;38;401411 111 4 — — _311 — _5_ H i - 2 7i41 :20j41| 11| • 4 - - — _ U I 100 I 5-; l l 1 3 7-445.501411 111 1 — — _ U I 90 I 5 i n 4 7:49:50|41| 11| n t — —' 111 100 |_5_ 1 1 1 — 5 7;55:101 411 111 . 4 .. . 111 109 | 5 111 __6 _ 8 i _ 3 Jj40 J 4 i | _ r i I „ 4 - - — _JL1I _100 I 5 111 7 -Si-HlZQ. \ HI1 -111 „ __J1_ i ' — — - M l -J0J3 _J2_ 111 8 8_;_9: 0|41| 11| 4 — 111 100 H i - 9 8;12: Oi 411 11J 4 111 105 5 l l 1 _1Q 8;14: Oj 411 | 4 111 100 | 5 i n Table 5.4 Note that i n the case of non-productive a c t i v i t y (31), the computer assigns zero to the r a t i n g f a c t o r . From t h i s data the f o l l o w i n g r e s u l t s are obtained: HOBK MEASUREMENT SAMPLING SUMMARY •••*•«• COST JOB START PROD + PROD TOTAL AVG MAN CENTER POS NUM DAY SUPPORT OBS OBS HRS/PIECE 41 1 2 5 93 102 7.277 41 2 2 5 98 105 8. 1S8 41 6 2 5 104 105 8.513 41 8 2 5 83 105 6.692 41 10 1 5 94 105 7.907 41 11 4 5 101 105 8.468 41 12 1 5 91 105 7.6C9 41 13 3 5 103 104 8.265 *** WMS SUMMARY COMPLETE • STANDARD TIME FROM .'. HOBK MEASUREMENT SAMPLING JOB PERCENT RELATIVE AVG MAN TOTAL STD STD NUM P ACCURACY HRS. OUTPUT TIME OUTPUT (PARTS) (MIN.) PARTS/HR 2 90.35 ± 3.2 % 30.680 3335 .552 109 1 93.10 ± 3 1.7 ft 22.698 4550 .299 200 3 99.10 ± 2 !.0 % 8.265 1500 .331 181 4 96.19 ± 3 1.8 % 8.468 875 .643 93 END OF THE JOB EXECUTION TERMINATED Ta b l e 5.5 These are the summarized r e s u l t s . For complete p r i n t o u t s see Appendix E. 65 Table 5.6 shows a comparison between the standard c a l c u l a t e d without and with the r a t i n g f a c t o r . JOB STD. CALCULATED STD. CALCULATED RATIO NUMBER WITHOUT BATING WITH BATING (LATCHES/HOUR) (LATCHES/HO UB) 0 2 0 109 109 1.00 0 1 0 205 200 1.03 0 3 0 181 181 1.00 0 4 0 98 93 1.06 Table 5.6 Table 5.7 compares the standard s et by work sampling with the a c t u a l output and the standards s e t by time study. JOB STANDARD SET BY ACTUAL STANDARD SET EY NUMBER *WORK SAMPLING *0UTPUT* *TIME STUDY 0 2 0 109 105 119 0 1 0 200 197 190 0 3 0 181 186 191 0 4 0 93 103 116 T a b l e 5.7 * This standard i s measured i n Latches/Hour. 1 Based on the r e p o r t of January and February 1978. 66 In Table 5.7, i t can be seen that the standards s e t by means of work sampling were c l o s e r to the a c t u a l output reported by the foreman o f the l a t c h assembly department, 5.2 TIME REQUIRED TO SET TEE STANDARD TIME The time needed by an a n a l y s t to s e t standards (computed i n t h i s chapter ) by (i) work sampling and ( i i ) time study can be broken down as seen i n the f o l l o w i n g t a b l e . TIME STODY HOURS Breaking down of t h e elements i n t o components .25 Taking the r e a d i n g s 4.50 C a r r y i n g out computations 2.50 TOTAL 7 . 2 5 WORK SAMPLING HOUBS E s t a b l i s h i n g a c t i v i t y codes .25 Taking the r e a d i n g s 7.50 C a r r y i n g out computations .50 TOTAL 8.25 Ta b l e 5.8 6 7 5-3 SUMMARY OF THIS CHAPTER From the study presented i n t h i s c h a p t e r , i t can be concluded t h a t : 1. r Work sampling i s a p p l i c a b l e to a s h o r t c y c l e r e p e t i t i v e o p e r a t i o n such as the assembly of a l a t c h , where the standard time v a r i e s from 0 . 3 to 0 . 6 minutes, depending on the type of l a t c h (see Table 5 .5 ) . 2. - The r a t i n g f a c t o r seemed t o have a s m a l l e f f e c t on the standard time obtained (see Table 5 . 6 ) . 3 . - The time r e g u i r e d to s e t standards was 12% l o n g e r i n the case o f work sampling (see Table 5 .8 ) . 68 C HA PTE'S VI CONCIOSIOHS 1. - Instead o f standard s t o p watch, work sampling can be a p p l i e d t o s h o r t c y c l e assembly o p e r a t i o n s without s u f f e r i n g any l o s s of accuracy. 2. - Work sampling appeared t o be more expensive than time study i n terms of a c t u a l man-hours r e g u i r e d on tested a p p l i c a t i o n s s t u d i e d . However, the accuracy achieved by means of work sampling was s l i g h t l y higher than the accuracy obtained by time study s i n c e e x t r a o b s e r v a t i o n s were taken. A feed back method such as a simple programme f o r a p o r t a b l e programmable c a l c u l a t o r could be used to compute the number of necessary r e a d i n g s f o r a given c o n f i d e n c e l e v e l a f t e r a g i v e n number of readings. I f t h i s i s done, i t i s l i k e l y t h a t the economics i n terms of man-hours would favour work sampling because the study c o u l d be terminated when the d e s i r e d accuracy l e v e l was achieved. 69 3. - Work sampling must be co n s i d e r e d t o be a more ac c e p t a b l e method p s y c h o l o g i c a l l y and co u l d be performed by a l e s s s k i l l e d , l e s s expensive t e c h n i c i a n . 4. - The ques t i o n of the importance of r a t i n g i s c o n t r o v e r s i a l . I t seems to be l e s s important i n work sampling and t h i s may be r e l a t e d o n l y t o the grouping of elements n e c e s s i t a t e d i n work sampling technigues. 5. - Durlnq the work sampling s t u d y , the a n a l y s t has more time t o observe the o p e r a t i o n f o r methods improvement. 70 BIBLIOGRAPHY Whitmore D.A., WORK MEASUREMENT, The I n s t i t u t e of P r a c t i t i o n e r s i n Work Study, O r g a n i s a t i o n and Methods, 1975, I n t e r n a t i o n a l Labor O f f i c e , INTRODUCTION TO WORK STUIY, four impression 1974, Geneva. Dun and B r a d s t r e e t , KEY BUSINESS RATIOS IN CASTA LA, 1S73, M e r r i l Lynch P i e r c e Fenner S Smith Inc., HOW TO R f AD FINANCIAL REPORT, 1973. J o u r n a l s of I n d u s t r i a l E n g i n e e r i n g . A.I.I.E. Barnes R., MOTION AND TIME STUDY, S i x t h E d i t i o n , John Wiley & Inc. 1968. Mundel M., HANDBOOK OF INDUSTRIAL ENGINEERING AND MANAGEMENT, Second E d i t i o n , F r e n t i c e - h a l l , 1971. Buff a £., MODERN PRODUCTION MANAGEMENT, Fourth E d i t i o n , John Wiley S Sons, 1973. Bertrand L. Hansen, WORK SAMPLING FOR MODERN MANAGEMENT, P r e n t i c e - H a l l Inc, 1960. Schmid H., WORK MEASUREMENT SAMPLING, U n i v e r s i t y of Dayton 1970. Schmid M., APPLICATIONS MANUAL - WORK MEASUREMENT SAMPLING, U n i v e r s i t y o f Dayton, 1970. Caruth D.L. GUIDELINES FOR ORGANIZING A WORK MEASUREMENT PROGRAM, 1971. APPENDIX A DETERMINING THE NDHBEB OF CYCLES TO STUDY 72 TIME STUDY The number of c y c l e s which must be timed i n order to a t t a i n a d e s i r e d l e v e l of accuracy depends on the d u r a t i o n of the b a s i c time of the c y c l e , and on the d i s p e r s i o n of the b a s i c times obtained d u r i n g the study. Eg. 1 g i v e s a measure of the v a r i a b i l i t y of data about i t s average. The v a r i a b i l i t y i s r e p r e s e n t e d by S, the standard d e v i a t i o n , which i s expressed as f o l l o w s : d = X-X computed from each rea d i n g of the element s e p a r e t e l y before sguaring and then summing. X = I n d i v i d u a l r e a d i n g s of an element. X = Mean or average of a l l readings of an element. Z = Sum o f l i k e items. 8 •= Number o f readings of an element. T h i s eguation may be expressed as f o l l o w s f o r machine computation ( F r i d e n , Monroe, Marchant, e t c . ) : assuming t h a t t h i s r e p r e s e n t s the v a r a b i l i t y of a huge group of s i m i l a r readings or the parent p o p u l a t i o n (a commonly tenabl e assumption), another measure, Sx, the standard e r r o r of the mean (or average) , may be computed from Eg. 2, which i n d i c a t e s the probable v a r i a b i l i t y o f t h e averages of groups of N values of X ( D 73 about the mean value. sx = s / / T (2) The property of t h i s l a s t measure i s such t h a t 95 per cent of the probable values of X (average of the element) w i l l l i e w i t h i n ±2Sx of the t r u e average. Hence, i f 2Sx i s egual or l e s s than 5 per cent of X, we may say t h a t the chances are a t l e a s t 95 out of 100 t h a t our average f o r the element t o which the r a t i n g w i l l be a p p l i e d i s whithin +5 per cent of the true average r e p r e s e n t i n g the performance we observed. I f the s e l e c t e d l i m i t i n g c o n d i t i o n i s not met, we may work Eg. 2 backward, using the S we f i r s t o b t a i n e d , s e t t i n g 2Sx egual t o 5 per cent of X, and s o l v i n g f o r N*, which w i l l i n d i c a t e the number of the re a d i n g s t h a t w i l l p r o b a b i l y be needed. Indeed, i t i s t h i s l a s t p r o p e r t y t h a t makes t h i s t e s t f e a s i b l e , easy and convenient, and economical t o use, a f t e r c e r t a i n mathematical manipulations of the formulas have been made.; Combining Eg. 1 and 2, we may s t a t e : Sx = 1/ S e t t i n g 5 per cent of X egual t o 2Sx, we get: 0.05X Where H* i s the r e g u i r e d number of r e a d i n g s . in NUMBER CF OBSERVATIONS IN WORK SAMPLING Work sampling or a c t i v i t y sampling i s based on the t h e o r i e s of sampling and p r o b a b i l i t y . The p i l o t study g i v e s an estimate of the p r o p o r t i o n (p) o f time spent on a p a r t i c u l a r a c t i v i t y being s t u d i e d . The l i m i t s of e r r o r are s e t two standard d e v i a t i o n s (or, more c o r r e c t l y , two standard e r r o r s ) from t h i s estimate i n order to ensure t h a t the observer may be 95 per cen t c o n f i d e n t t hat the estimated e r r o r i s c o r r e c t . The s t a n d a r d - e r r o r formula f o r a b i n o m i a l d i s t r i b u t i o n i s : Where N i s the number of ob s e r v a t i o n s which must be made to ensure a c e r t a i n r e g u i r e d accuracy. The l i m i t s are s e t a t two e r r o r s , t h e r e f o r e : L i m i t s of e r r o r (L) = 2y p(1-p)/N Rearranging t h i s formula produces one f o r e s t i m a t i n g the number of o b s e r v a t i o n s r e g u i r e d t o a t t a i n a r e g u i r e d e r r o r : N = 4p(1-p)/L* s e t t i n g L = 0.05p N = 1600{1-p)/p APPENDIX B 1. - Improved o b s e r v a t i o n sheet f o r Work Sampling study. 2. - Programme f o r a Hewlett Padkard c a l c u l a t o r to generate random times d u r i n g the a v a i l a b l e time f o r production. 3. - Form f o r r e c o r d i n g the random times. WORK SAMPLING STUDY Sheet No. Date DEPARTMENT 49 - PACKING LINE ACTIVITY TOTAL PERCENTAGE 1. Open box 2. I n s e r t s t r i k e 3. Assemble trim s and p l a c e i n box - 4. I n s e r t l a t c h , screw packs 5. F i l l s h i p p i n g case, c l o s e box 6. Prepare m a t e r i a l , remove empty boxes 7. Walking 8. Wai t i n g f o r p a r t s 9. P i c k up p a r t s from the f l o o r 10. Out of area 11. Conversing TOTAL WORKING % OUTPUT =' TOTAL IDLE % P.F.A. = Tit le Fy\NDQ//\ TWAE. FOR A WORK 5MAPUN.C P a g e _ J o f__i Programmer U . y iLLt .1 np>n«; STEP INSTRUCTIONS INPUT DATA/UNITS KEYS OUTPUT DATA/UNITS I KEY IN PROCRA/A, II 1 a 3 STORE. SEED U_ STO II O I F I PGR/A STORE THE TI/AE FOR: II 1 I P II 3.1 START FIRST COFFEE BREAK START 1 STO II 1 1 1 1 3.3 END FIRSTCOFFEE BREAK END \ STO II Z 1 START LUNCH START Z STO ! 3 1 i 1 3.T END LUNCH END Z 1 STO I n - 3.1 START SECOND COFFEE BREAK END SECOND COFFEE BREAK START 3 STO 5 II END 3 Ls iD__ fe i i CLEAN-UP START 4- L J H D L X I L . i GENERATE RANDO/A R/S 1 i 1 t TWAES I I 1 I i r II i r THE CALCULATOR WILL G.ENER CTE 1 IL _ I L — AN INFINITE NUMBER OF II II RANDOM TI/AES. " I I 1 __JL_ THE. ANALYST WILL QENERME AS ll 1 II 1 /AANY AS HE WILL NEED. 1 ii ll L AT THE. END OF THE RUN, 1 II II II U; IS RECORDED AND USED 1 F _ l FIX, ll <\. I L __. FOR THE NEXT RUN . i RCL II 0 II II 1 u ; 1 II II 1 . ... ' . _ j i i " i n i il l l l — - — ! 11 1 i i i • c r . T ~ ] i 1 HP-25 Proqram Form 73 T i t i e M ^ m j j y A E i > ^ B J B S L R . V A I 1 0 N S D U i l l l C J l / A L A V A l i A B L L J Q R p a g e . Switch to PRGM mode, press [7J [ PRGM [ , then key in the program. PRODUCTION _ L . _ o f _ L _ . DISPLAY KEY ENTRY X Y Z T COMMENTS LINE CODE OO \\-.\V' IS73 " • • * • V- 01 02 Tr Z.HOO RCL 0 Ui- 1 Tr 03 51 +• Ui-l-nr 04' 05T 5 5 05 1403 (U;-| + TTV 06 1501 q FRAC Ui 07 2300 5T0 0 Ui OS 09 0& 73 8 & 8. Mi UL __ - — 10 ' 05 5 8.5 Ui 11 12 <o\__ 8.5 U; 01 ~ 1 7 8.5U-, 13 73 7. 8.5Ui 14 05 5 7.5 8.5Ui 15 16 51 + 7.5+8.5U] a t A RANDO/A NU/ABE.R B ETWEfcN 7.5 4* Ho.O 2401 PXI_ V START 1 t > 17 i\ ~ X^y t START 1 18 19" 1344- F*<y QTO 44 t START 1 START I "> TEST F OR THE FU «T DELAY. 20 2402 RCL 2 END | i t 21 yfsr~ F*Vy END I t 22 1301 21 ~ 2403 ~ CTO 01 "* *< y END l~1 t END I j •- - -• 23 24 25 26 t "RCL 3 START 2 t 21 " * * y ~ t START 2 V; 1441 F\<.y_ START 2 7 27 28 29 30 1344 C.TO 44 t START 2 VTEST F )R THE SE« rOND DELAY. 2.404" "RCL 4 END 2 t -- — - IHSI" Fx*y " ENDZ t 1301 CTO 01 • END 2 t L J - 31 32 "33~ 34 2T~* 2405" 2.1 t END I RCL 5 START 3 X^Y _f_>i.y_ t START 3 m i _ _._t START 3 1 35 1344 _ _C«T0 44 . t START 3 - > TEST F RD DELAY. 36 240b 1 W RCL (o ENO 3 t 37 ~Fx*y END 3 t 38 39 ----- 1301 CTO 01 END 3 t t ) 11 2407 - * \ y END 3 START 4- 41 T i o r ~ Fx<.y START 4- ' " t START 4- • TEST F( )R THE FO! flRTH DELAY. 42 43 "GTO" o r STARTS' X*< y t 44 45 "1400 FH./AS t -s~ — m e I F t AYED FOUR TI/AES. 46 47 _____ ^ _J^78: L.F»Vs: _ i36"l —rGT0 61 t _ _ __ /"THE Tl// VE JS DlSPl 1 I ,;t) i ! REGISTERS 5TABXI. „t_iD__. R 5  STML3... END 3 R 7 START H- H E WL ETT [hfjj I>AC K A R D U; - FRACTIONAL PART OF [CTT+U'rO 5] \\mEKE O ^ U i l f,= 7.5 + 8.51V, TORK SAMPLING STUDY RANDOM TIMES FOR OBSERVATIONS 8 9 10 11 12 •n 14 15 : 10 1 0 1 0 1 0 Lunch 1 0 1 0 1 0 2 0 2 0 2 0 2 0 Time 2 0 2 0 20 3 0 3 0 • 3 0 3 0 30 3 0 30 7 30 40 1+0 40 4 0 it 0 4 0 Coffee 40 50 50 Coffee Break 5 0 . 50 5 0 5 0 50 5 0 6 0 6 0 6 0 Lunch Time 6 0 6 0 6 0 6 0 6 0 Clean-up PSEUDO RANDOM TIMES ' UNIFORMLY DISTRIBUTED o< U. < , l 1 U ± = Fractional part of [ O + U. _ -) 5 ] °i-l U = o Date =. 80 A P P E N D I X G Programme f o r a Hewlett Packard c a l c u l a t o r f o r f i n d i n g the number of c y c l e s r e g u i r e d i n a Time Study to achieve 95 % confidence w i t h i n ± 5 % o f e r r o r . HP-25 Program Form 8 1 T i t l e ^ E Q U l f i t l - L ^ E j y - d N C S F O R ̂ C O N F I D E N C E . W I T H I N t S ^ E R R f l R p ^ ) _ o f . 1 Programmer _ ^ _ \ a L X M , a B O ^ „ X ^ M B C M ^ . , „ J S 2 £ . STEP INSTRUCTIONS INPUT DATA/UNITS KEYS OUTPUT DATA/UNITS 1 KEY IM PROCRA/A 1 II i ! JN ITJAL IZE 1 F H P M M 3 ENTER CYCLE Tl/AE L U O = L & E _ Y S _ - . - .Mr ONLY IF THE 1 II II OPERATOR ISTO BE r ~ I I I I II .RATED, FOLLOW THE J L J L . J L NEXT Z STEPS; _ H L Z . 1 I 11 - OTHERWISE SKIP THE/A. 1 I1 ! i| 5 PRESS ENTER - r r t " ir II II h ENTER THE RATING R I N O -II KEYS II 11 7 RUN FOR FIRST CYCLE :.R/S. II ll II 1 N 8 REPEAT STEP5 r i i r ~r 3 To 1 , 10 TI/AES r - " i 11 i .."S. FIRST EST1/AATE OF i II ir ~ i ! N ' . N N* FLASHES TWICE i r n r r "> I 10 KEY FEEDING. DATA [ 1! .-II 11' "> 1 ll II II 1 N', N UNTIL N APPROACHES r J L L z j m N' . • - J L JL .. I I I THE PROCBAW . _•• - • _ H L _ ~ ] _ " 7 J - Y>_ //VEAN : .STOPS WHEN I - i r n r ~ 11 \ N>N* .'"" : \ - X J _ L T ~ J . J _I.Z_ _FOR - A NEW CYCLE . . i JFT. J L 1 PRESS R/S BEFORE • r _ L _J i ..ENTERING THE L J L _ IL _ J L 1 _ „ FIRST READING ' i r r~ i r r - -NOTE TO THE USER: i ir ~ i ~ " r i L 1 IF" RATING IS NOT SPECI : IED r ~~I  i r I I — • • ii T H E PROCRA/A ASSU/AES 100 ~ r i r n b) THE PROGRA/A TAKES A MY r r j r n r j L j ..KINDS OF UNITS OFH/AE. [ . z i r r x ZJLT J i II r r II i i i 11 1! l - l P-25 Program For 82 T i t l e JM-QL1A_EP READ ING, FOR S^/c, COMF\D_NCE-_\y jJJ i_5 l ! / a ERRQ& Page_J of__L__ Switch to P R G M mode, press |T| [ PRGM | , then key in the program: /AARCH 2., \^12> DISPLAY KEY ENTRY X Y Z T COMMENTS LINE CODE OO WWWWv _N^N_*_ Pv X 01 02 x 5: y X R .1571. X 0 3 _ ' I 3 Q S croos L O O P FOR . THE 04 " ~ M X. Rx 05"~ ~ 3 3 EX* l _ Rx "F IRST T E N CYCLES. 06l_ _T.OZ. 2" : I O O Rx 07 71 Rx 08 _l3lO C T O 10 R x — 09"" 10~ — 22 .— Rx _+ N 11 " —E- f— N 12 — - - o» J 1 N . 13" ~ ~ 0 O - 07 \o N 1'4_ 15 _ri2i x i y N lO F K ^ V N lO 16 1347 C.TO 4 7 N 10 17 _ _2HfO-T' N IO. N ' IS C O M P U T E D 18 ~ - <bl X Nfcx1 to 19 " " 2 4 0 7 ; R C L 7 -,X ~ N ix 1 : 20 ~ ~vsoi T £ x Y " H N£.xz IO 21 " ^ r 10 . J_._.NA.«L_C&xi- 2 2 — — 14-02. /X lO A »o - — . - - - 2 3 _ 04-" - 4. 4- 24~ 61 X 4 A IO 25 " —fc l 4 0 A 26 " 2 4 0 7 R C L 7 - X 4 0 / \ . 27~" — - r ' r 4-0 A Mx 28 "~I502"~" gxV 29 " -J4"IT00~ RXO N l 3 0 — " 1 * 1 4 F R/S N ' 31 " 1 4 7 4 F R / S N ' 32~ "WT02 FIX 2 N' 33 - " " 2 . 4 0 3 R C L 3 N N ' 34 ' "~35- """T4-4-1 ~ 1 3 4 7 PK<. y N N ' ! C T O 47 N N ' . 36 ri421 F X X OMAN • r / A E A N I R E A D J N C 37 30 " 74 1433 F R E C , X READ X _j 39 1348 QTO 4 8 J__LT_.A JL_\yj^ C LE ._ .__ 40 41 42 43 44 45 46 47 48~ 49 ~ -14-7I H 4 3 4 " " ' F R / S F STK. QTO 0 0 C L E A R T H E . . . _ S T A C K S . REGISTERS R-7- £Rx. 40yN£,x1-(_x,)l\2 APPENDIX D IBS programme f o r generating random times under uniform d i s t r i b u t i o n d u r i n g time a v a i l a b l e f o r production f o r Work Sampling study. An example c o v e r i n g two p o s i t i o n s o r s t a t i o n s with f o r t y two o b s e r v a t i o n s each. $SIGNCN WMSA F0RM=8X11 PAGES=50 PRIO=LOS *U B C UBC» 84 THIS IS NOT A PASSWORD I ! ! ! ! $RUN *FTN SCARDS=*SOURCE* PAH=NOSOURCE C ****************4*^ C C THIS PROGRAM FINDS RANDOM TIMES UNDER UNIFORM C DISTRIBUTION FOR A WORK SAMPLING STUDY. C C IT IS ARBITRARILY SET FOR WEISEE, WHEN THE C SHIFT IS CONSIDERED NUMBER ONE, STARTING AT C 7:30, AND FINISHING AT 16:00. C THERE ARE FOUR SCHEDULED DELAYS; AT 9:40, C 11:50, 14:30 AND 15:55. THE LENGTH OF C TBE DELAYS I S : 0:15, 0:30, 0:12 AND 0:05. C C » » > NOTE: C 9:20= 9.333 9.35= 9.583 C 9:40=9.666 9:55=9.916 C 11:45=11.750 12:15=12.250 C 11:50=11.833 12:20=12.333 C 12:30=12.500 13:00=13.000 C 14:30=14.500 14:42=14.700 C » » > 1 5 : 5 5 = 1 5 . 9 1 6 16:00=16.000 C C THIS PROGRAM USES TWO SUBROUTINES FROM THE C LIBRARY, ONE IS CALLED »RAND», WHICH GENERATES C RANDOM NUMBERS, AND THE OTHER ONE IS CALLED C »SSORT», WHICH SORTS THE TIMES IN ASCENDING ORDER. C c > » » » » » > » » » » » » > » » » » » » > » > » » » » c C > » » » > N O T E TO THE USER OF THIS PROGRAM : C C THE NUflBER 3 IS ATTACHED TO A FILE. IT HAS TO BE C DECLARED IN THE RUNNING COMMAND C TBE ONLY CARD THIS PROGRAM REQUIRES IS, USING C COLUMNS 1 AND 4 THE NUMBER OF PAGES AND THE NUMBER C OF JOBS TO BE STUDIED. C > > > > > » » » » » » » » » » » » » » » » » » » » » » » c DIMENSION TIME (2187) ,IHR (2187) , MIN (2187) ,ISEC(2187) C C * READ THE SEED FROM FILE *S1ED» AND SAVE IT. C READ (3,1) SEED 1 FORMAT(F8.7) SAVSED=SEED C C * INITIALIZE COUNTER C J=0 c C * LOOKS FOR A VALUE FOR NUMBER OF C * OBSERVATIONS REQUIRED. IF IT DOESN'T C * FIND IT IN CARDS, IT ASSIGNS 1 TO C * NUMBER OF JOBS AND 1 TO THE NUMBER C * OF PAGES (27 OBSERVATIONS). C READ (5,2,END=3,ERR=3) NP,NJOB FORMAT (12, 1X,12) 85 GO TO 4 WRITE (6,25) FORMAT(1X,20X,19HERROR IN CATA****** ) NP=1 NJOB=1 THE TOTAL NUMBER OF OBSERVATIONS IS FOUND IF (NJOB.LE. 1) NJOB=1 IF(NP.LE.I) NP=1 N=NP*21*NJ0B TBI ELEMENTS OF THE ARRAY TIME ARE GENERATED CONTINUE SEED=RAWD(SEED) T=7.5+8.5*SEED 4* * * *^ CHECK IF TIME IS HBITHIN PRODUCTIVE PERIOD > » » » » > FIRST COFFEE BREAK » > » » » 15 MIN=.25 HR. IF ( (T.GE. 9. 3333) .AND. (T. LE. 9. 5833) ) GO TO 5 » » » » » LUNCH TIME...... ..... 30 MIN=.50 HR. IF((T.GE. 11. 833).AND. (T.LE. 12.333)) GO TO 5 » » » » » SECOND COFFEE BREAK » > » » » 12 MIN=.20 HR. IF ( (T.GE. 14. 500) .AND. (T.LE. 14.700) ) GO TO 5 » » » » » > CLEAN UP TIME » » » » 5 MIN=.08 HR. IF (T.GT.15.916) GO TO 5 OBSERVATION 8ITHIN PRODUCTIVE TIME J=J*1 TIME(J)=T IF(J.LT.N) GO TO 5 THE ELEMENTS ARE SORTED USING A SUBROUTINE FROM THE LI CALL SSORT (TIME,N, 3) TIME IS CONVERTED TO •HR,HIN#SEC» DO 8 1=1,J IHR(I)=IFIX(TIME(I) ) XMIN=60.0* (TIME (I) -FLOAT (IHR (I) ) ) MIN (I) =IFIX (XMIN) ISEC(I)=IFIX(6.0*(XMIN-FIOAT (MIN (I) )) +0i 005) CONTINUE C 86 C * NOTE: ISEC(I) HEP RESENTS 10 SECONDS C c « « « < « « « « « « < < « < « < < « « « < « « « < < « « < « < C THIS PART OF THE PROGRAM PRINTS THE FORMS FOR C WORK SAMPLING STUDY, C C IT ALSO PRINTS THE RANDOM TIMES FOR THE OBSERVATIONS. C C NOTE : THIS PARTICULAR FORMAT HAS BEEN DEVELOPED C FOB WEISER LOCK CO. IN CANADA C < < < « « « « « « < < « « « < « « « « « « « « < < « « < « « c c * c 10 FORMAT<»1«, -55H - - • , -• • -.- - » -1X,7HSTATI0N ) 20 FORMAT(1X, -55H| L | TIME | IDENTIFICATION |S|I| WORKER | |S| | - 2X,3HNO. ,12) 30 FORMAT{••», -55H _; .__ „ , ) - 2X,3HNO.,12) 40 FORMAT{1X, -55fl| I | | | JDEPJOPRI JOB |P|N| | |DAY i H|LOT|, - 1X,8HPAGE NO.,11) 50 FORMAT(1X, -55H| N |Hfi:MN:S|SUM|NUM| NUMBER |E|T|A C|P RTJ NUM11|SIZ|) 60 FORMAT(1X, -55HI E | I | | I I I CIE| - | | IF| |, - 1 X , 9 H C A T E _ _ ) 65 FOSMAT(1X, -55H| I I I I I I I IBJ \ I |T| I, - 1X,8HCCMMENTS ) 70 FORMAT{* + », ~55H -. • • - • - : •• ) 100 FORMAT(1X,1H|,13,1H|,I2,1H:,I2,1H:,I1, 43H| | | I I I I I 111 I) 110 FORMAT(1X, -55H| | I I I I) C C * INITIALIZE COUNTERS FOR THE LOOP C NFIBST=0 LAST=N-NJOB C C » PRINT THE FIRST HEADING OR RETURN AFTER PRINTING 27 LINES C DO 250 I=1,NJOB NSTOP=0 LINE=0 NPAGE=1 NFIRST=NFIRST*1 LAST=LAST*1 C C > » » P R I N T THE HEADING C WHITE(6,10) WRITE (6,20) I WRITE(6,30) 87 WHITE(6,UO) NPAGE WRITE(6,50) WRITE(6,60) WRITE(6,65) WRITE(6,70) C C * » T H E OBSERVATION SHEET IS PRINTED C DO 200 K=N FIRST,LAST,NJOB LINE=LINE+1 NSTOP=NSTOP+1 WRITE (6,110) WRITE(6, 100) NSTOP,IHR(K) ,HIN(K) ,ISEC(K) WRITE(6,70) C C * TEST FOR NEW PAGE C IF ( (LINE. GE. 21) . AND . (K. LT.LAST) ) GOTO 170 C GO TO 200 170 LINE=0 NPAGE=NPAGE*1 WRITE (6, 10) WRITE (6,20) I WRITE(6,30) WRITE (6,4 0) NPAGE WRITE(6,50) WRITE (6,60) WRITE(6,65) WRITE (6,70) 200 CON UNO E C C * c c 250 CONTINUE C 300 WRITE(6,350) SAVSED ,NJOB,NP,SEED 350 FOR0AT( ,O',/ 1 20X,35HTHE ORIGINA1 SEED FOR THIS RUN IS :,1X,F8.7,/ 2 21X,7HF0R : ,12,14H STATIONS WITH,1X,I2,12H PAGES EACH.,/// 3 29X, 26HTBI SEED FOR NEXT RON IS :,1X,F8.7,/// 4 58X,14HEND OF THE RUN ////) C C * THE * SEED* IS SAVED FOR THE NEXT RUN C BACKSPACE 3 WRITE(3,1) SEED STOP END $Run - l o a d 3=seed 7--temp T= 3 2 / 0 2 SSignoff 88 1 I-JUJL-1 I SEN TI f IC AT 10 N |S|I| I - | | T |DEP|OPR| JOB~ |P|N| N |HR:MN:S|NUH|NUM| NOHBER |'E|T| E 1 I I I | | 1C | E | J J 1_J_ _1 J ±_±RL _MORKER_| 1S J I |DAYjH|10T A C|P BT|HUH|I|SIZ 1 1 |F| 1 1 ITI 1 _ J l _ 2 i i 2 i 0 l _ 1 1 1 J. _ J _ l _ i . . -1 . • 1 111 1 2J 7:35:4! - 1_ I i 1 1 1 1 1 1 M l 1 _ _ 3 l 7:46i2l __1 I 1 1 1 _ 1 1 1 _1_ 1 1 4| 7:55:11 I I I 1 I I I 1 1 i 1J_ 1 _ 5i_2i59;1| , ; 1 1 1 1 1 I I I - -1 1 111 1 _ _ 6 i _ 8 i J 7 i 5 l _ 1 _ _ 7 i _ 8 i 4 8 i 3 l _ 1 1 1 1 1 | J L _ J i H -J.1J _ 1 _1 1 111 1 81 8 i J 3 i 2 l _ _ JL_ 1 I I 1 I I I . J . . I _111_ 1 -_9l_8i58i11_ _. 1 I 1 1 1-1 1 . .: 1 1 111 1 101 9: 4:p_l_ 1 I I I 1 1 1 1 :. 1 j 111 1 111 9i58:2l _ 1_ 1 i 1 J L _ _J._J._1. _1 j 1 12110: 6:41 1 1 1 1 1 _ 1 1 1 •1 - • 1 HI I _13l10j.14l3l„ 1 14,| 10:32:31 I I I 1 i 1 J L i l l -111— _ _ J L _ _ _ _ 1 •-- H I 1 15l10i_44;4| 1_ I I 1 .1 J _ J _ ± 1 1 111 I 16J10:46:11 _ _ i 1 I 1 1 1 1 1 ..- .. |. . 1 • HI I _17l!Qi47i41_ I _ _ i 1 1 1 JL- . I l l 1 . „ 1 1 I J L _ _ . _1J111i_6i21_ __1 . _ JL _ 1 111 1 19111:22:11, —1 . I I 1 J. ___JL1 i . _ 1 1 .111- 1 20111:29:31 1 1 1 1 1 1 1 1 .111 1 -UlllkHlllL- _ 1 1 I 1 J _ __ 1-1-1. _1_ 1 -111— STATION NO. 1 PAGE N0.1 DATE COBBENTS 8 9 L |_TIME _J IDENTIFICATION I | | J |DEP|OPR| JOB N |HB:MN:SjNOM|NOM| NUMBER E | | | | J | i _ „ L _ - i - ± J _ L ._ I 22j11:45:4| I I S|I| WORKER | |S| P|N| | |DAY|H|LOT £|T|A C|P RT|NUM|I|SIZ C|E| | | I F | JL-JJU J I 12J I I I .nniimn I. i _J4iJ2i31i2J^ JL I 1 JL_1_JL I ^5U2i35i31_. I 2 6 1 1 2 : 3 8 : 5 1 I I I 28112:59:51 1 l I 1 1 1 I HI 1 1 I_29jj3i_3i4j _ l _ i 1 1 1 1 •JL.-. I 111 1 1 1 30U3i20i5i_ i .„•{„•;; ;•„•. 1 1 1 1 1 • i _ •-• I- - 111 1 1 1 31|13;36:3} 1 -1 _J 1 I 1 1 1 : _ 11J I I I 32113:44:4 1 -1 _ _ i 1 1 1 j 1 111 1 1 .33113;56:2| I - J ._ _. _J 1 1 1 1 1 111 1 1 1 34|14: 5:01 1 1 1 I 1 1 1 .••_JL__- 1 HI -1 1 1 35|14;14;4| 1 1 1 1 1 I . 11.J . I I l_J6U4i19i3j 1 1 1 1 . i j 1 1 l_J2lli»iMliil_„ I I l_38l!4:51:5JL_ I J 1 1 I 1 J JL : I -1UL 111_ ; I I I^39l15i_6i0l . i 1 ' 1 1 1 1 . _JL . 1 .111 I I I 40115:18:01 _ i 1 1 1 1 1 1 1 . I __111_ 1 1 1 41|15:28:1| 1 _1 1 1 1 1 1 • I 11JL. 1 1 1 42115:32:31 1 _J 1 1 1 1 1 __1U I I JLJL J.UL .11JL .1___11±_. .1 1JJL_. ____1 111 STATION NG. , 1 PAGE NO. 2 DATE. .__ CGBMENTS 90 L I . T I M E 1__IEJNTIFICJ1I0N | S 11 I J I | JDEPJOPBT JOB |P|U N |HR:MN:S|NUM|NUH| NUMBER | I | T E I I I I I I IC | E .—l—l—l-l—l—l^——.—^l-lM I . J l _ 2 : _ 5 : i l J L . I i i j._±. i I .-Hl-llMlU—l I I I .2l_8i_0_0i 1. I J l _ 8 : 55j_5l [ I I .-1-1. 1 I -_JL_1. I _ J L _1. JL._. I 10( 9:13;1|, I I I I I _ J 3 l 1 0 : 2 i i : 2 l _ L. JL i i JLrJL I J-U_______± 1. I J^llQiHllll—XL. I I I __JL I I .-1.1. I i 17|10:51:11 I I ', ,. I .JL_JL_ 1 1 111 , 1 1 18111:15:31 I __1 - I I I I I 1 1 H I 1 i 19111:28:51 I _ j_ I I 1 1 1 1 H i 1 1 | 20i11:31:_i I I I \ 1 1 1 I I t 2 1l11 : i*3i2i I 1 1 1 \ 1 1 M l WORKER | j S| | |DAY|H |I»GT A C|P R T | N U M | I | S I Z i i i Pi J J LU .11L J 11JL. J .111-. 111. 111. All S T A T I O N NO, 2 P A G E NO. 1 DATE COHHENTS 91 1 l _ T I J J _ _ J IDENTIFICATION I I | i | D £ P | O P f i | JOB N |HR:MN:S|NUM|NUM| NOEBER E I I I I i I . _ _ 1 _ _ 1 _ _ 1 _ 1 _ _ _ 1 L I 1,22111:47;t}| „ _ i •J . 1 1 . 1 1 H i ., •• 1 1 | 23i-12:29:3| I _ 1 i i j _ l _ . .1 . 1 HI 1 1 I 21112x3 2 i U I . _ ! _ j I i l I JL 1 11J_ I i I 25112:36:4 1 I . _ ! ' • • • ' i i .JL.1 JL_ . 111 1 1 I 26jJ2i46i11 1 i ._1 1 ! 1 I I JL 1 _ _ 1 1 1 _ 1 27U2i59-1| I _ 1 _ 1 1 1:1: - -1 | 1 I t I l _ 2 8 i J J i _ 0 i 3 l _ . 1 I 1 1 . 1 _ 1 _ _ . .1 _ • 1 _ _ 1 1 1 _ ! 1 1 29113: 3;5| i I j 1 1 11 :i:-„-:::. .. j ! I l_JfiJLUi29i11_. 1 1 I 31113:39:41 l _ „ L 1 1 " l 1 11 I ... |... I I J._ _^JLLJb__ t 1 l_32113:48231 I . * ! _ _ : — - 1 . 1 1 .1-1 J. 1 l l l _ i i 1 33113:57:01 I 1 .  : 1 1 1 1 1 1 1 111 1 1 1 341141 7x51 I _ L 1 1 l l JL 1 H i 1 1 L.3!l14iJ6: 51_. I _1 1 I I I 1 • :ih ; r:Ml,-" 1 1 U 3 6 U 4 i 2 0 i 3 l _ _ _ 1 _ _ . L 1 1 i i - J _ _ _ 1 | 1 37114:50:31 I • 1- , • i I I 1 JL-- — 1 • 1 1 1 _ 1 1 l_38114x57141 I ._1 | I I 1 I JL. . 1 .... i l l . . , . . 1 1 1 39115:17:31 I J 1 1 1 1 - 1 111 1 1 1 40115:23x21 I ._1 • • ] 1 1 . 1 _ 1 _ _ . J .--- I • 1 1 1 . i i I 41l15x31:5JL_ I | 1 1 . 1 _ J 1 1 _ _ 1 1 1 _ I I I_ii2lJ5xl2xil_. 1. 1 1 J JL_ „ 1 1 1 _ _ _ S|I P|N E|T C|E I JIORKEJLI 1 S | 1 )DA? |H |LOT 5 C|P RT | NOM |I | SIZ I I IF I 1 L _ _ _ 1 T 1 _ _ _ STATION NO. 2 PAGE NO. 2 DAT E__ COMMENTS TBE ORIGINAL SEED FOR THIS RON IS : .576090 FOR : 2 STATIONS WITH 2 PAGES EACH. THE SEED FOR NEXT RUN IS : .011186 APPENDIX E E x p l o s i v e view of the l a t c h e s d e s c r i b e d i n Chapter f o u r . An example o f the p r i n t o u t s obtained f r o n tbe computer.   uu uu uu uu uu uu uu uu uu uu uu uu uu uu uu uu uu uu uu uu uuuuuuuuuuuu uuuuuuuuuu BBBBBBBBBBB BBBBBBBBBBBB BB BB BB BB BB BB BBBBBBBBBB BBBBBBBBBB BB BB BB BB BB BB BBBBBBBBBBBB BBBBBBBBBBB CCCCCCCCCC CCCCCCCCCCCC CC CC CC CC CC CC cc cc cc cc CCCCCCCCCCCC CCCCCCCCCC WW WW MM MM SSSSSSSSSS WW WW MMM MMM SSSSSSSSSSSS WW WW MMMM MMMM SS SS WW WW MM MM MM MM SS WW WW MM MMMM MM SSS WW WW MM MM MM SSSSSSSSS WW WW WW MM MM SSSSSSSSS WW WWWW WW MM MM SSS WW WW WW WW MM MM ss WWWW WWWW MM MM ss ss WWW www MM MM SSSSSSSSSSSS WW WW MM MM SSSSSSSSSS AAAAAAAAAA AAAAAAAAAAAA AA AA AA AA AA AA AAAAAAAAAAAA AAAAAAAAAAAA AA AA AA AA AA AA AA AA AA AA $RUN WMS.OB 5=PARAM(1,6)+DATA-41+PARAM(7) 6=*SINK* 7=*DUMMY* 8=-FILE8 9=-FILE9 10=-FILE10 l l = - F I L E l l EXECUTION BEGINS WMS- EDIT INPUT PARAMETERS ACTIVITY CODES 11 21 22 23 24 31 32 33 SHIFT NUMBERS 1 2 3 4 SHIFT START TIMES 750 9999 9999 9999 SHIFT END TIMES - 1600 9999 9999 9999 DELAY 1 DELAY 2 DELAY 3 DELAY 4 DELAY 5 START 1 933 1175 1450 1591 9999 0 9999 9999 9999 9999 9999 0 9999 9999 9999 9999 9999 0 9999 9999 9999 9999 9999 LENGTH 1 25 50 20 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ACCUM. DELAYS 1 25 75 95 103 103 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 GAMA = 0.80 READ DATA CARDS COMPLETE TOTAL DATA CARDS - 840 SORT FOR PART 1 COMPLETE *** WMS PART 1 COMPLETE SORT FOR PART 2 COMPLETE WMS PART 2 - END OF JOB v o WORK SAMPLING SUMMARY IDENTIFICATION CC POS 11 21 NO. OBSERVATIONS 41 1 82 11 ACT. (NOT RATED) 41 1 78.1 10 .5 ACT. (RATED) 41 1 75.7 10 .5 NO. OBSERVATIONS 41 2 80 13 ACT. (NOT RATED) 41 2 76.2 12 .4 ACT. (RATED) 41 2 78.3 12 .4 NO. OBSERVATIONS 41 6 90 12 ACT. (NOT RATED) 41 6 85.7 11 .4 ACT. (RATED) 41 6 85.8 11 .4 NO. OBSERVATIONS 41 8 64 17 ACT. (NOT RATED) 41 8 61.0 16 .2 ACT. (RATED) 41 8 60.9 15 .1 NO. OBSERVATIONS 41 10 89 0 ACT. (NOT RATED) 41 10 84.8 0 .0 ACT. (RATED) 41 10 87.3 0 .0 NO. OBSERVATIONS 41 11 97 2 ACT. (NOT RATED) 41 11 92.4 1 .9 ACT. (RATED) 41 11 94.9 1 .9 NO. OBSERVATIONS 41 12 89 0 ACT. (NOT RATED) 41 12 84.8 0 .0 ACT. (RATED) 41 12 86.7 0 .0 NO. OBSERVATIONS 41 13 101 0 ACT. (NOT RATED) 41 13 97.1 0 .0 ACT. (RATED) 41 13 97.2 0 .0 NO. OBSERVATIONS TOTAL 692 55 ACT. (NOT RATED) TOTAL 82.5 6 .6 ACT. (RATED) TOTAL 83.3 6 .4 WS OUTPUT FILE COMPLETE END OF JOB RUN PAGE 1 ACTIVITY CODES 23 24 31 22 1 1.0 1.0 0 0.0 0.0 0 0.0 0.0 0 0.0 0.0 2 1.9 1.9 1 1.0 1.0 1 1.0 1.0 0 0.0 0.0 5 0.6 0.6 0 0.0 0.0 1 1.0 1.0 1 1.0 1.0 1 1.0 1.0 3 2.9 2.9 0 0.0 0.0 1 1.0 1.0 1 1.0 1.0 8 1.0 1.0 2 1.9 1.9 4 3.8 3.8 1 1.0 1.0 1 1.0 1.0 0 0.0 0.0 1 1.0 1.0 0 0.0 0.0 1 1.0 1.0 10 1.2 1.2 1 1.0 0.0 1 1.0 0.0 0 0.0 0.0 8 7.6 0.0 5 4.8 0.0 1 1.0 0.0 5 4.8 0.0 1 1.0 0.0 22 2.6 0.0 32 8 7.6 0.0 6 5.7 0.0 1 1.0 0.0 14 13.3 0.0 5 4.8 0.0 3 2.9 0.0 8 7.6 0.0 0 0.0 0.0 45 5.4 0.0 33 0 0.0 0.0 0 0.0 0.0 0 0.0 0.0 0 0.0 0.0 1 1.0 0.0 0 0.0 0.0 1 1.0 0.0 0 0.0 0.0 2 0.2 0.0 TOT 105 89.0 105 95.4 105 99.1 105 77.9 105 92.0 105 98.7 105 88.6 104 99.1 839 92.5 WORK MEASUREMENT SAMPLING SUMMARY PAGE NO 1 COST START PROD + PROD TOTAL AVG MAN CENTER POS JOB NUMBER DAY SUPPORT OBS OBS HRS / PIECE 41 1 0 2 0 5 93 102 7.277 41 2 0 2 0 5 98 105 8.198 41 6 0 2 0 5 104 105 8.513 41 8 0 2 0 5 83 105 6.692 41 10 0 1 0 5 94 105 7.907 41 11 0 1 0 5 87 90 7.182 41 11 0 4 0 5 14 15 1.286 41 12 0 1 0 5 91 105 7.609 41 13 0 3 0 5 103 104 8.265 *** WMS SUMMARY COMPLETE STANDARD TIME FROM WORK MEASUREMENT JOB PROD + PROD TOTAL PERCENTAGE RELATIVE AVG MAN TOTAL OUTPUT STD. TIME STD. OUTPUT NUMBER SUPPORT OBS. OBS. P ACCURACY HRS. (PARTS) (MIN.) (PARTS/HOUR) 0 2 0 378 417 .91 + 3.1 % 30.680 3335 .552 109 0 1 0 272 300 .91 + 3.7 % 22.698 4550 .299 200 0 3 0 103 104 .90 + 1.9 % 8.265 1500 .331 181 vo oo

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