Analysis of Fluid Flow through the Grinding Zone

A theoretical model of fluid flow in grinding has been developed by an analysis of fluid flow through a porous medium. Fluid tangential velocity, radial velocity, depth of penetration into the wheel, and the useful flow rate through the grinding zone are predicted by using this model. The analysis indicates that the nozzle position, nozzle velocity (or flow rate), and the effective wheel porosity are the three main factors which most significantly influence the useful flow rate through the grinding zone. A dimensionless effective wheel porosity parameter is introduced which is the ratio of the effective wheel porosity to its bulk porosity. By fitting the theoretical analysis to available experimental results, creep feed wheels were found to have much bigger dimensionless effective porosities than conventional wheels, which enhances their ability to more effectively pump fluid through the grinding zone.

Experimental Measurement of Fluid Flow Through the Grinding Zone

An experimental test rig was developed to measure the amount of grinding fluid which flows through the grinding zone in straight plunge grinding. Proportional relationships were generally obtained between the flow rate from the nozzle and the useful flow rate of fluid passing through the grinding zone. The percentage of applied fluid passing through the grinding zone was found to depend mainly on the bulk porosity of the grinding wheel and the nozzle position. Wheel dressing has only a secondary influence, which is attributed to its influence on the surface porosity of the wheel. The workspeed and wheel depth of cut have virtually no influence.