Digital Modelling of Sintered Diamond Wheel Topography with Random Grain Distribution for Protrusion State Evaluation in Grinding

Abstract

Grinding process is a complex grain-workpiece interaction. Due to the on-site measurement limitations, empirical knowledge is generally utilized for condition planning regardless of irregular grain protrusion, leading to unstable grinding quality. Accordingly, a novel digital modelling of sintered diamond wheel topography with random grain distribution factors of spatial position, rotation angle and geometrical shape was proposed to evaluate the grain protrusion. Grain interference recognition and multiple concentration matching were also developed to improve simulative precision and speed. The objective is to realize the condition planning with statistical mechanism rather than empirical knowledge. First, grain shedding coefficient was tuned to simulate the resin- and metal-bond based wheel topographies. Then, the influence on grain protrusion uncertainty was investigated at different equivalent grain sizes and grain concentrations. Finally, tool cutting performance was experimentally analyzed with the simulative wheel topographies under shedding and frictional wear conditions. It is shown that the simulative wheel topographies present the skewed distribution of grain top height after grain exclusion, conforming to the actual surfaces with high fitness. Small wheel topographical deviation is achieved at small equivalent grain size and large grain concentration, wherein the influence of spatial position is more significant. The resin-bond based wheel tool under shedding condition increases the active grain number but decreases the equivalent grain top height to produce the multiple-stage increase of ground surface roughness, against the bathtub-like change for the metal-bond one under frictional wear condition. Hence, the condition planning could be guided by the digital model associating with grain protrusion.

Keywords: Grinding, Diamond grain, Wheel topography, Digitization, Grain protrusion