Precision grinding of silicon nitride ceramic with laser macro-structured diamond wheels

Silicon nitride ceramics are extremely difficult and time-consuming to machine with conventional methods due to high strength and hardness. 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 laser macro-structured method using pulsed laser is proposed and applied to produce certain macro patterns on the surface of diamond grinding wheel. Grinding performance of the macro-structured grinding wheel is tested and compared with a non-structured grinding wheel. It is found that the laser structured pattern has a strong influence on the grinding characteristics. The normal and tangential grinding forces for laser macro-structured grinding (LMSG) condition are 16.3% (15.1%) lower than that in the conventional grinding (CG) condition. The grinding temperature and subsurface damage decrease significantly for LMSG condition. However, due to the influence of pattern geometry, the improvement for surface roughness is not obvious. The groove wear does not reveal a significant increase in wear of the structured grinding wheel.