| 摘要 |
PROBLEM TO BE SOLVED: To improve stability and reproducibility of release in an optical disk substrate to be injection molded by providing either of a stationary metal mold or moving metal mold with a annular clearances for blowing off air for releas ing the disk substrate from the disk metal molds and regulating the variation in these clearances within a specific value in one round. SOLUTION: The stationary metal mold 1 and the moving metal mold 2 face each other and a cavity 3 is formed between the moving metal mold 2 and the stationary metal mold 1 when the moving metal mold is closed. A cut punch 6 and an ejector 8 are movably disposed on the moving metal die 2 side. A spool 4 is formed in the upper part on the inner side of the cut punch 6 and a stamper 5 is mounted on the rear surface of the stationary metal mold 1. The respective parts are previously temporally assembled and while the metal mold clearances 7a and 7b are measured for one round at the time of assembly, the inner side parts of a stationary bushing 10 and moving bushing 11 are regulated to diminish variation in such a manner that the variation within the one round is kept within 8 μm. |
