To solve a problem wherein a circumferential velocity difference between an inner circumference part and the outer circumference part of a carrier causes an accuracy difference in the surface roughness, parallelism and flatness in a single work in a conventionally used polishing pad whose diameter of openings on the surface is same and whose carrier of a planetary gear type polishing device executes circular movement of autorotation and revolution.
The polishing pad is formed into a doughnut-like shape and changes the opening diameters so as to reduce the dispersion of the surface roughness of the polishing surfaces of the outer circumference part and the inner circumference part and uniformize the accuracy of the parallelism and the flatness, thereby improving the manufacturing efficiency.
NAKAMURA SHINJI
TOYODA KAZUHIKO
HAMAI SANGYO
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