Study on the grinding behavior of laser-structured grinding in silicon nitride ceramic

Silicon nitride ceramics are extremely difficult and time-consuming to be machined with conventional methods, such as turning and grinding. Laser-assisted machining has been a field of extensive research during the past decade, as it is a promising solution to enhance the machinability of many difficult-to-cut materials, including silicon nitride ceramics. To enhance the processing precision of silicon nitride ceramic grinding, in this work, a method of laser structuring the surface of silicon nitride is proposed. The laser process allows to precisely control the dimensions of the generated features. Therefore, different patterns with equal silicon nitride surface area are produced in order to study the influence of the pattern geometry on the grinding behavior of the silicon nitride. Grinding performance of the structured silicon nitride is tested. The influences of grinding parameters, such as wheel speed and feed rate, are analyzed for their effects on the grinding force, surface roughness. It is found that the procedure of laser-structured silicon nitride has a strong influence on the grinding results. The grooves obtained by laser-structured silicon nitride are favorable for the flow of coolant, and the cracks generated inside the grooves weak the material locally. The laser-structured silicon nitride generally allows for a reduction of grinding forces by up to 63%, and it can effectively reduce the wear of the tool.