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UBC Theses and Dissertations
Virtual milling Bélanger, Isabelle
Abstract
Milling is used to manufacture a wide variety of metal parts, from simple to complex geometries, in small or large volumes. The requirements for these parts usually necessitate that the milling operation is accurate, but also the production rate must be as high as possible. These two requirements, which appear conflicting as first, are met if the milling operation is well planned. While NC programming is still based in many industries on past experience and practical knowledge, research in the areas of cutting mechanics, modelling and simulation are gradually changing the manufacturing practices. This thesis investigates Virtual Milling, which is the integration of milling simulation and CAD/CAM capabilities. Available milling simulation systems can simulate the process for one set of cutting conditions. The objective with Virtual Milling is to not only simulate the milling operation for the whole NC program, but also to integrate features such as feedrate scheduling. A milling simulation for the whole part was developed based on the analytical closed-loop milling model presented by Spence[36]. The input to the simulation is the cutter-workpiece intersections along the tool path. The simulation results include force, torque and power, and deflection along the tool path. The second part of this thesis is the implementation of a Virtual Milling framework. The first step is the selection of cutting conditions which is done during the NC programming. CAD/CAM software do not provide tools to select appropriate cutting conditions, therefore we established the requirements for such a tool using stability lobe theory. An interface was implemented in a commercial CAD/CAM software to demonstrate this. The milling simulation is then used to identify critical locations along the tool path, and it is also used to perform feedrate scheduling. Two offline approaches for feedrate scheduling were implemented, constraint-based feedrate scheduling and off-line adaptive force control, and evaluated to see if their use would lead to improved machining accuracy, better control of cutting forces, and improved machining time. Cutting tests were conducted and these approaches were also compared to an existing online adaptive force control.
Item Metadata
Title |
Virtual milling
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2004
|
Description |
Milling is used to manufacture a wide variety of metal parts, from simple to complex geometries,
in small or large volumes. The requirements for these parts usually necessitate that the milling operation is accurate, but also the production rate must be as high as possible. These two
requirements, which appear conflicting as first, are met if the milling operation is well planned.
While NC programming is still based in many industries on past experience and practical knowledge,
research in the areas of cutting mechanics, modelling and simulation are gradually changing
the manufacturing practices.
This thesis investigates Virtual Milling, which is the integration of milling simulation and
CAD/CAM capabilities. Available milling simulation systems can simulate the process for one
set of cutting conditions. The objective with Virtual Milling is to not only simulate the milling
operation for the whole NC program, but also to integrate features such as feedrate scheduling.
A milling simulation for the whole part was developed based on the analytical closed-loop
milling model presented by Spence[36]. The input to the simulation is the cutter-workpiece intersections
along the tool path. The simulation results include force, torque and power, and deflection
along the tool path.
The second part of this thesis is the implementation of a Virtual Milling framework. The first
step is the selection of cutting conditions which is done during the NC programming. CAD/CAM
software do not provide tools to select appropriate cutting conditions, therefore we established the
requirements for such a tool using stability lobe theory. An interface was implemented in a commercial
CAD/CAM software to demonstrate this. The milling simulation is then used to identify
critical locations along the tool path, and it is also used to perform feedrate scheduling. Two offline
approaches for feedrate scheduling were implemented, constraint-based feedrate scheduling
and off-line adaptive force control, and evaluated to see if their use would lead to improved machining accuracy, better control of cutting forces, and improved machining time. Cutting tests
were conducted and these approaches were also compared to an existing online adaptive force
control.
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Extent |
5053458 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-11-21
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0080731
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
2004-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.