WEAR OF GRINDING WHEELS – SOFTWARE FOR THEIR SELECTION

WEAR OF GRINDING WHEELS – SOFTWARE FOR THEIR SELECTION

ABSTRACT

An existing model of the grinding process has been upgraded to predict grinding wheel wear as G ratios. It has been successfully benchmarked against experimental results for several combinations of coolant wheel and workpiece. As a Windows-based application, it offers a rapid and versatile way of assessing the performance of grinding wheels and processes in a realistic way. For the best results, it should be benchmarked before use against appropriate experimental results.

KEYWORDS : Grinding; Software; Wear

INTRODUCTION

The key to a successful grinding process is the selection of the right wheel for the job. It must be able to provide the finish and accuracy required, and it should also wear enough to keep sharp, but not enough to lose its form and to grind unstably. Selection is normally empirical, and whilst this often works, it can throw up unexpected results, which may degrade the accuracy and integrity of the workpiece. A more scientific selection method would clearly be an advantage, but has been hard to develop because of the complex interactions which determine grinding performance.

A recent paper [1] is something of a breakthrough in this respect. A model is developed which is robust enough to predict grinding forces, workpiece temperature, and roughness from basic grinding data: machine settings, wheel and coolant specifications, dressing technique and workpiece properties. It is built around an advanced model of abrasive mechanics [2,3], and makes use of recent analysis of heat transfer effects in grinding [4] to calculate temperatures.

To calculate the effect of dressing on wheel topography. the model makes use of published data on the mechanical strength of vitreous bonds and abrasive grits, and data on the statistical variation of this strength. [5-7]. This allows the prediction of fracture pattern of the wheel as it is dressed, to which its topography, and sharpness, are directly related.

Application of the same methods to the interaction of the wheel with the workpiece as it grinds should allow the wear rate of the wheel to be calculated. In what follows, a method for doing this is described. Combined with the force prediction model already developed, grinding ratios can be calculated for a variety of grinding processes for which measurements have been published allowing validation of the calculations. The resulting algorithms are incorporated into a windows based application [8] which allows all the above parameters to be displayed as a function of metal removal rate.

Download full seminar papers At
http://www.enjineer.com/forum