When the roughness of the workpiece does not meet the standard, the grinding speed of the grinding wheel can be increased within the range of grinding wheel speed to improve the surface roughness of the workpiece. On the other hand, one can try to reduce the speed of the workpiece being ground. The purpose of this method is to increase the relative speed between the resin wheel and the workpiece. When the first method is not ideal, the longitudinal feed of the workpiece can also be reduced to reduce the strength of the grinding wheel workpiece, thereby preventing large-scale burns of the workpiece.