Abstract: The ultra-precision wheel normal grinding of binderless tungsten carbide aspheric mold is researched. The influence of grinding wheel initial position error on grinding accuracy is analyzed. The ground surface morphology and quality of binderless tungsten carbide aspheric are presented. And then, the grinding error compensation is optimized and the subsurface damage of mold is studied by focus ion beam. The results show that the grinding wheel initial position error model is useful to enhance the grinding wheel initial position accuracy. The morphology and quality of binderless tungsten carbide aspheric surface are inhomogeneous. The surface quality of aspheric center is better than that of aspheric edge round. Finally, after 3 times error compensation, there binderless tungsten carbide aspheric molds with 0.3 µm (PV) form accuracy and 8 nm (Ra) surface roughness are obtained, and no crack is found in subsurface of these molds.

Key words: binderless tungsten carbide;aspheric mold;ultra-precision grinding;error analysis;surface quality;subsurface damage