Analytical modelling of both parallel and cross grinding with arc-shaped wheel for grinding-induced damage and grinding force

Abstract

The distribution of the undeformed chip thickness (UCT) in the wheel-workpiece contact area is important to analyze the grinding-induced damage and the grinding force on brittle materials. Cross grinding (CG) and parallel grinding (PG) are two basic modes in aspherical grinding. However, fewer researches provided the calculation of the UCT distribution in CG or toric PG. To solve this difficulty, the 3D geometry of the contact area is modelled and divided into small pieces. The UCT distributions are calculated based on the material removal rate in each divided area and revised based on the normal distribution of the grit protrusion height. Surface roughness (SR) and subsurface damage (SSD) can be estimated with the basic equations (i.e., the relationships between depth of median/lateral cracks and penetration depth). To verify the proposed method, the experimental results on BK7 glass by Sun et al. were re-analyzed. Through the comparison of the simulation and experimental results, the factor Kf for CG and PG, which represents the randomness of the UCT, was treated separately. Then, the damages generated by #400 arc-shaped wheel were analyzed, and two SiC-ceramic samples were ground. The results explained why CG showed worse surface quality than PG. Moreover, the normal forces in grinding SiC ceramic by #200 arc-shaped wheel were measured and analyzed. The force model, based on the assumption of specific grinding energy on the single grit, provided a better understanding of material removal mechanism.