Material Removal Mechanisms in Diamond Grinding of Granite, Part 1: The Morphological Changes of Granite from Sawing to Grinding

摘要

An investigation is reported of the removal mechanisms of workpiece materials during the grinding of natural granite with diamond abrasive tools. This paper consists of three parts. Part 1 is concerned with the morphological features of granite surfaces at different stages, which ranged from rough sawing to fine grinding. Surface roughness on ground granite surfaces was also detected to check its dependence on the morphological features. SEM observations for rough sawing with a very large material removal rate exhibited a nearly pure fracture mechanism, whereas the morphologies for sawing with a smaller material removal rate revealed extensive fracture accompanied by some localized ductile flow in the form of plowed striations along the cutting direction. However, fine grinding exhibited a ductile material removal mechanism, in which case ductile flow prevails on the ground surfaces. The roughness on the ground granite surfaces decreased greatly as diamond grit size gradually reduced from sawing to fine grinding. Owing to the different concerns in sawing and fine grinding, different processing strategies to select machining parameters and fabricate diamond tools need to be adopted for the two grinding situations.