Stephen C. Veldhuis
- Courses7
- Reviews10
- School: McMaster University
- Campus:
- Department: Mechanical Engineering
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Location:
Hamilton, ON - Dates at McMaster University: June 2004 - October 2019
- Office Hours: Join to see
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Would take again: Yes
For Credit: Yes
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Mandatory
Awesome
Prof. Veldhuis is an ideal professor. Contrary to the other profs, he can manage to explain complex material in an understandable manner. He is able to make great connections between the content and real world. He also gives enough amount of prep material for midterms/exams.
Biography
McMaster University - Mechanical Engineering
Resume
1992
PhD
Manufacturing
1990
Master's degree
Mechanical Engineering
Carnegie Mellon University
1985
Highland Secondary
B. Eng. and Mgmt
Mechanical Engineering
McMaster University
Engineering
Materials Science
CFD
Numerical Analysis
Signal Processing
Optics
Statistics
R&D
Simulations
Analysis
Experimentation
Labview
Programming
Research
Data Analysis
Mechanical Engineering
Mathematical Modeling
Finite Element Analysis
Matlab
Science
Form error in diamond turning
The main feature of ultraprecision
single point diamond turning (SPDT) is its ability to produce high quality surface finishes on the order of nanometers while meeting tight form tolerances on the order of micrometers. This capability allows for the production of optical devices with minimum post-processing operations. The issue of form error is critical since it may severely compromise the performance of the designed optical system. Tool-workpiece relative vibration is a major cause of this error. In this article
the authors have demonstrated that imbalance of the spindle is a major cause of form error which eventually leads to a structured error called “spindle star” that appears as straight concentric spokes radiating out from the center of the part. The formation of a spindle star pattern can be explained using Campbell's rotordynamics analysis. This analysis explains how assisted air-hammering instability and cross-coupling effect of the air-bearing spindle can contribute to spindle star. This experimental approach used force and accelerometer data with the help of modal analysis to conclude that spindle star is a synchronous error and is a function of rotational frequency of the spindle and its harmonics. The integer harmonic from the Campbell's waterfall diagram predicts the number of spokes in the spindle star. It was also observed that the height of the spindle star undulations increases with higher rotational speed. It was also observed that cutting material and tool geometry has no influence on the spindle star formation; rather this is an inherent characteristic of air-bearing journals. Finally
the analysis was successfully validated by changing the natural frequency of the spindle by adding mass.
Form error in diamond turning
Veldhuis
Mcmaster Manufacturing Research Institute
McMaster University
Hamilton
ON Canada
Director
Mcmaster Manufacturing Research Institute
Hamilton
Ontario
Professor
Director (MMRI) and Braley-Orlick Chair in Advanced Manufacturing Engineering
McMaster University
