Transcription Molding of Micro-scale Patterns using Ultra-high-speed Injection Molding
Xue Han, Hidetoshi Yokoi, Tatsuo Takahashi, Wookyu Kim
Center for Collaborative Research,The University of Tokyo
JAPAN

Keywords: Ultra-high-speed injection, Transcription molding, Prism pattern


In order to investigate the potentiality of micro-scale transcription in polymer using ultra-high-speed injection molding machine, which can realize a maximum injection speed of 1000-2000mm per second, a series of injection molding tests were carried out. In this paper, PMMA was molded to replicate the electroformed nickel stamp featuring V grooves in 50 micrometer pitch, under a various of injection molding conditions including vacumizing cavity process.
The surface configuration of molded samples were observed at Confocal Scanning Laser Microscope and then transcription ratio, which was defined as the ratio of V groove depths both in the molded sample and in the injection mold, was measured for evaluating the transcription levels of samples. A fine transcription ratio of 0.97 was achieved under a injection ratio of 800cm3/s, a molding temperature of 80 degreeC and a hold pressure of 120MPa.
The present research showed that, influencing factors of both filling cavity process and hold pressing process are different, in which the former was mostly controlled by polymer temperature, whereas mold temperature and hold pressure mainly influenced hold pressing process. Also, the vacuumizing of cavity was discussed in this paper, concluding that this is an important factor of influencing the transcription process during ultra-high-speed injection molding.
In this paper, the fact that, transcription quality could be considerably improved using ultra-high-speed injection molding, was proved and further systematic research is in progress.