<p>The paper presents a process to restrain edge chipping in grinding segmented mirrors using powder-added filler based on the mechanism of stress wave propagation. Powder of the same material as the mirror is mixed into the filler and added to the splicing gap to reduce tensile stress. The stress wave propagation mechanism in the workpiece with powder-added filler is revealed based on stress wave theory. The influence of the gap thickness on the instantaneous stress state is analyzed by numerical calculation. Stress wave propagation when using powder-added filler is also calculated and compared with the situation using pure filler. Maximum tensile stress can be reduced with smaller gap thickness and powder-added filler. The variation in the size of cracks in scratching tests proves the results derived in the numerical calculations. As verified in contract experiments, cracks near the gap are restrained using filler mixed with powder in the grinding process.</p>