Investigation of Material Removal Mechanism in Grinding: A Single Grit Approach

This thesis has investigated material removal mechanisms in grinding by considering single grit workpiece interaction. The investigation was performed both experimentally and using finite element simulation. Rubbing, ploughing and cutting mechanisms occurring during the grinding process were studied at the micro scale. Due to its nature the rubbing phase occurs in a very narrow region of grit-workpiece engagement and is difficult to examine under a microscope and so was investigated using FEM simulation. The ploughing mechanism was thoroughly investigated using both experimental tests and FEM simulations, and a similar trend was observed for the pile up ratio along the scratch path from the experimental tests and the FEM simulations. Ploughing and cutting mechanisms in grinding were found to be highly influenced by grit cutting edge shape, sharpness and bluntness. Cutting is the prominent mechanism when the grit cutting edge is sharp, but ploughing is more prominent when the grit cutting edge becomes flattened. In the case of multiple edges scratch formation, ploughing is dramatically increased compared to single edge scratches. Feasibility of ground surface simulation using FEM is demonstrated using multiple pass scratch formation in a cross direction. Although chip formation mechanism is developed at a relatively higher depth of cut (greater than 10 μm), at small scales down to 1 μm, FEM simulation was not a suitable method to use. To reduce the drawbacks of FEM simulation in micro scale cutting, a meshless simulation technique such as smooth particle hydrodynamics is recommended for future studies.