Original paper(Vol.46 No.7 pp.808)

Estimation of the size of chipping formed at work corner in grinding of brittle material

Yamaguchi Katsumi; Mizutani Katsumi; Tanaka Yoshio

Abstract:This paper aims to establish a practical way for predicting the size of chipping at work corner by grinding force. This is based on the idea that the grinding force on an abrasive grain must act as the concentrated loading force for the extension of well developed crack causing the chipping.
To find relationship between the size of chipping and grinding force, the grinding experiments with a single diamond point of three dimensional shape were carried out on an optical glass in a wide range of grinding conditions (wheel depth of cut, work feed rate and tip radius of the point). An analysis is performed to estimate the grinding force on the model that the force integrates the traction on the contact face between grain and work during a traverse of the grain that is passing over a prior groove,
The experimental results show that the 3/2 power of the chipping size is proportional to the maximum grinding force during a traverse of grain. The grinding force calculated from the grain depth of cut based on the grinding geometry is not always consistent with the real force measured in the experiment, because the real grinding process includes the fracture type material removal (over-cut grove). The real grinding force was smaller than the calculated one in the over-cut groove, while it was larger in the under-cut groove. More exact evaluation for the grinding force, or the chipping size can be made by compensation of grain depth of cut using some experimental results and the analytical model proposed here.

Key Words:chipping, grinding force, single point grinding, grain-work interference, residual removal, material fracture