INJECTION MOLDING METHOD FOR OPTICAL INFORMATION RECORDING BASE

摘要

PURPOSE:To reduce the percentage of rejects such as burn and birefringence by forming an optical information recording base while a mold is resonated. CONSTITUTION:A node section of resonance generated by waves of a mold 1 is retained by using a retaining component having a possible smallest contact area. Then, a nozzle 4 of a molding machine is brought into contact with a sprue 3a of a fixed side mold 3 and a molding material is injected into a cavity 2a through said sprue 3a to carry out molding, and also the mold 1 is resonated by wave length (n) by generating supersonic vibration in a vibrator 10 by supersonic vibrator 12. (n) in said (n) wave length resonance is m/2 ((m) is positive integar), and resonance is carried out in a manner that a loop section of resonance conforms with the cavity 2a and vibration effect of supersonic waves can be utilized effectively to the maxmum. The flow of the molding material to be filled in the cavity 2a can be made good by said arrangement and reheating can be carried out in a short time.