Experiences in the Grinding of Silicon Nitride on a Lower Cost High Speed CNC Grinder

Published

January 16, 1998

Author(s)

T W. Hwang, Eric P. Whitenton, Christopher J. Evans

Abstract

An investigation into high speed grinding of ceramics has been conducted to understand machine dynamics, wheel wear, and ground surface morphology. Some preliminary results are reported for modal testing and wheel wear together with microscopic observations of the ground surfaces. The modal testing of a 4-axis computer numerical control (CNC) grinder reveals a vertical vibration of the wheel acting as a local ?jack-hammer?. As the wheel speed increases above 10000 rpm, the spindle and the motor cause vibrations. Wheel wear test using a single-layer plated diamond wheel for grinding of silicon nitride shows that the grinding ratio (G-ratio) is a nearly constant 840 mm3/mm3, and surface roughness (Ra) of the ground specimen decreased from 1.6 ?m at the beginning to 0.4 ?m at the end of wheel life. Measured normal force per unit width was found to increase reaching 200 N/mm at near the end of wheel life starting from about 10 N/mm at the beginning. This is primarily due to the development of wear flat areas on the active cutting points. Much remains to be done to separate the various affects alluded to in the high speed grinding of ceramics.

Citation

NIST Interagency/Internal Report (NISTIR) - 6079

Report Number

6079

NIST Pub Series

NIST Interagency/Internal Report (NISTIR)

Pub Type

NIST Pubs

Download Paper

https://doi.org/10.6028/NIST.IR.6079

Keywords

ceramics, Grinding, high-speed grinding, wheel-wear

Citation

Hwang, T. , Whitenton, E. and Evans, C. (1998), Experiences in the Grinding of Silicon Nitride on a Lower Cost High Speed CNC Grinder, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.IR.6079 (Accessed April 23, 2024)