- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- Mechanics and dynamics of ballend milling
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
Mechanics and dynamics of ballend milling Lee, Peter Pak Wing
Abstract
Ball end milling has been used extensively in current manufacturing industry in producing parts with sculptured surfaces. Due to its complex cutter geometry, ball end milling mechanics and dynamics have not been studied until recently. In this research, the mechanics and dynamics of cutting with a special helical ball end cutter are modeled. A unified mathematical model, which considers the true rigid body kinematics of milling, static deformations and forced and self excited vibrations, is presented. The ball end mill attached to the spindle is modeled by two orthogonal structural modes in the feed and normal directions at the tool tip. For a given cutter geometry, the process dependent cutting coefficients are obtained by applying oblique tool geometry to the fundamental properties such as shear yield stress, shear angle and average friction angle measured from orthogonal cutting tests. The three dimensional surface finish generated by the helical flutes is digitized using the true kinematics of ball end milling process. The dynamically regenerated chip thickness, which consists of rigid body motion of the cutter and structural vibrations, is evaluated at discrete time intervals by comparing the present and previous tooth marks left on the finish surface. The process is simulated in time domain, by considering the instantaneous regenerative chip load, local cutting force coefficients, structural transfer functions and the geometry of ball end milling process. The proposed model predicts cutting forces, finished surface and chatter-free condition charts, and is verified experimentally under both static and dynamic cutting conditions. The model allows process planners to select cutting conditions to minimize dimensional surface errors, shank failure and chatter vibrations for end milling operations.
Item Metadata
Title |
Mechanics and dynamics of ballend milling
|
Creator | |
Publisher |
University of British Columbia
|
Date Issued |
1995
|
Description |
Ball end milling has been used extensively in current manufacturing industry in producing
parts with sculptured surfaces. Due to its complex cutter geometry, ball end
milling mechanics and dynamics have not been studied until recently. In this research,
the mechanics and dynamics of cutting with a special helical ball end cutter are modeled.
A unified mathematical model, which considers the true rigid body kinematics of
milling, static deformations and forced and self excited vibrations, is presented. The
ball end mill attached to the spindle is modeled by two orthogonal structural modes in
the feed and normal directions at the tool tip. For a given cutter geometry, the process
dependent cutting coefficients are obtained by applying oblique tool geometry to the
fundamental properties such as shear yield stress, shear angle and average friction angle
measured from orthogonal cutting tests. The three dimensional surface finish generated
by the helical flutes is digitized using the true kinematics of ball end milling process.
The dynamically regenerated chip thickness, which consists of rigid body motion of the
cutter and structural vibrations, is evaluated at discrete time intervals by comparing the
present and previous tooth marks left on the finish surface. The process is simulated in
time domain, by considering the instantaneous regenerative chip load, local cutting force
coefficients, structural transfer functions and the geometry of ball end milling process.
The proposed model predicts cutting forces, finished surface and chatter-free condition
charts, and is verified experimentally under both static and dynamic cutting conditions.
The model allows process planners to select cutting conditions to minimize dimensional
surface errors, shank failure and chatter vibrations for end milling operations.
|
Extent |
5851244 bytes
|
Genre | |
Type | |
File Format |
application/pdf
|
Language |
eng
|
Date Available |
2009-01-30
|
Provider |
Vancouver : University of British Columbia Library
|
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.
|
DOI |
10.14288/1.0098975
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Graduation Date |
1995-11
|
Campus | |
Scholarly Level |
Graduate
|
Aggregated Source Repository |
DSpace
|
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.