EXPERIMENTAL-STUDY ON TRANSCRIPTION OF MINUTE GROOVES IN INJECTION-MOLDING

In order to analyze the mechanism of the transcription in injection molding of poly-carbonate resin, the relationship between the molding factors and the transcription of a minute groove, which is 0.55-mu-m wide and 70 nm deep, has been studied. The results obtained are as follows. (1) The development of the transcription of minute groove is caused by creep deformation of the resin. When the melt temperature, mold temperature, injecting rate and holding pressure are high, and when the holding time is long, the transcription is improved. (2) When the injecting rate and holding pressure are low, and the holding time is short, the transcription difference between the upstream side and the downstream side of the resin flow is larger. But, when the injecting rate and holding pressure are high, and the holding time is long, the transcriptions of this difference become nearly equal. (3) When the waiting period between holding stage and cutting gate is long, the transcription drops due to the back flow of the resin at the gate. (4) The thickness of the vitrified layer just after filling is about 100 approximately 150 nm at the mold temperature 120-degrees-C, as estimated from the transcription model obtained in this study.