Wear of electroplated diamond tools in lap-grinding of Al2O3 ceramic materials

Abstract

Current development of modern products, together with ever-increasing demands for their operation and usage, necessitate the search for new processing methods. Abrasive machining is widely used in many industrial areas, especially for processing difficult-to-machine materials such as advanced ceramics. Grinding with lapping kinematics, also called lap-grinding, is still one of the innovative methods of abrasive processing being under continuous development. It combines the advantages of grinding and lapping, allowing for meeting high design requirements and, at the same time, ensuring efficient and safe machining. This paper presents experimental and modelling results on the application of electroplated wheels with diamond grains (D107 and D64) in the lap-grinding of Al2O3 ceramic materials in a single-disc lapping machine configuration. The grain size along with the thickness of the nickel bond influenced the material removal rate and surface roughness obtained. The relationship between the material removal and the processing time was approximated by asymptotic mathematical functions. Moreover, the empirical models were modified according to the Preston's equation when the unit pressure increased. The linear and nonlinear regression models enabled accurate curve fitting to the surface roughness data. Microscopic images of the active surface of electroplated diamond tools were analyzed in the aspects of the resultant tool wear and technological effects. In addition, the results were referred to the analysis of microscopic images of the suspension taken from the active surface of the tool after subsequent tests. The suspension consisted of particles of fragmented abrasive grains as well as chips removed from the machined surface.