Experimental study of plastic cutting in laser-assisted machining of SiC ceramics

In this paper, the cutting process of laser-assisted machining (LAM) of SiC ceramics is studied. Three processing states of brittleness, plasticity and thermal damage are determined based on the characterization analysis of surface integrity, tool wear and chip morphology, and the surface roughness and tool wear regression model established under the plastic processing state are verified. Firstly, the surface integrity, tool wear and chip morphology are investigated by the single-factor experiment of laser power to explain the material removal mechanism according to the material fracture theory and to determine the laser power range of plastic cutting (185 W-225 W). Then the Box-Benhnken experimental scheme is designed to establish a multivariate prediction model based on the response surface methodology (RSM) to obtain the regression equation of surface roughness and tool wear and further analyze the interaction between process parameters. Finally, the experimental values of surface roughness and tool wear are compared with the predicted values through optimization analysis. The results show that the maximum error is 5 % and 7.57 % respectively, which proves that the model has good prediction ability. The surface roughness and tool wear regression prediction models provide guidance for the selection of plastic cutting process parameters for SiC ceramics.