Title

A thermal study of cylindrical grinding

Date of Completion

January 1999

Keywords

Engineering, Mechanical

Degree

Ph.D.

Abstract

The research reported in this thesis covers the thermal aspects of shoe centerless and center-type cylindrical grinding. An analytical thermal model of the cylindrical grinding process has been developed based on 2-D heat conduction to study the workpiece temperature distribution. The model takes into account the effect of heat accumulation within a cylindrical workpiece subjected to successive passes of temperature inputs moving along the workpiece periphery. By applying average heat transfer coefficients at the workpiece periphery in the form of temperature inputs, the cooling effect of the grinding fluid in the cylindrical grinding was also considered. Film boiling was used as the criteria for thermal damage avoidance. ^ The workpiece temperature field was obtained numerically by discretizing the heat source moving process during grinding. In each time increment, the temperature distribution was obtained by the superposition of the temperature fields caused by constant temperature inputs at the grinding zone and/or shoe/workpiece contact zones, and a convective boundary condition in the form of finite difference temperature inputs at the workpiece periphery. By using a single temperature input, this model can be applied in center-type cylindrical grinding. The model can also use direct grinding power inputs using a finite difference technique. ^ A unique experimental rig was designed and developed to measure the in-process workpiece temperature distribution and grinding forces during cylindrical grinding. The rig enabled temperatures at different depths, and grinding force data to be measured under various workpiece speeds and infeed rates. The rig was modified to measure workpiece temperature responses from shoe/workpiece friction. ^ With appropriate temperature or power inputs at the grinding contact zone and average heat transfer coefficients on the workpiece boundary, the modeling results match the experimental results reasonably well. By comparing model experimental data, the average heat transfer coefficients along the during wet grinding were estimated. These, in turn, were used to estimate workpiece temperature distributions under similar coolant applications to illustrate ways in which the model can be used. Sample model applications for simulations of shoe centerless grinding and shoe/workpiece friction are provided. The model and experimental results show good correlation. ^