Investigations on materials removal mechanism during laser-assisted grinding silicon nitride ceramics

Abstract

Grinding of silicon nitride ceramics has been seen the existence of processing problems such as low processing efficiency and high grinding forces. In response to the problem this paper mainly analyzes the processing mechanism of the laser-assisted grinding process, simulates the grinding process of a single abrasive grain grinding the surface of the silicon nitride microgroove through the coupled simulation of the smooth particle hydrodynamics (SPH), and finite element method (FEM), and analyzes the change of the material removal process with the grinding force and the depth of damage. The simulation results show that the grinding force and damage depth are significantly reduced when the abrasive grain cuts in the position of microgroove proximity due to the change of microstructure on the crack extension direction. An indentation experiment was carried out on silicon nitride ceramics, when the indenter was pressed in the closer position of the microgroove, the diagonal crack of the indentation would be extended to the side of the microgroove, which showed reasonable agreement with simulation results. It also proved that the laser heat source had a softening effect on the material. Two kinds of microgroove surfaces with different groove spacings were designed, and the laser-induced surfaces were subject to grinding experiments. The experimental results show that compared with the non-groove surface, the micro-grooved surface can significantly reduce the grinding force and improve the machining efficiency, and modifying the parameters of the grinding process can impact the effectiveness of laser-assisted grinding in reducing grinding force.