| Summary: | 碩士 === 中原大學 === 機械工程研究所 === 100 === In order to help the melt flow and eliminate the weld line, the mold temperature will be increased to have good quality parts. The mold temperature becomes an important issue for the plastic injection molding,especially for the thin and high gloss parts. Also, the mold design has great effect on part quality and manufacture efficiency. In general, the mold is made and assembled in room temperature. The ejection system can move smooth when mold assembling. During the injection molding,the mold temperature will higher then room temperature to help the melt flow and the mold will has thermal expansion and deformation. Than the ejection pin and mold insert will sometimes crash each other and have the wear problem.
In this study, there are six gap designs 0.003mm、0.005mm、
0.010mm、0.023mm、0.030mm、0.040mm and five mold temperature
60℃、80℃、100℃、120℃、140℃ have been apply to find the gap design effect between ejection pin and mold insert with nylon resin. Besides, the thermal expansion and melt flow have been simulated to show the gap design result.
It was found that the higher mold temperature and smaller gap design will easily to have the crash and wear problem. But the oversized gap design will have the flash issue. For the nylon resin, the gap design is from 0.005mm to 0.03mm and 0.01mm to 0.023mm when the mold temperature is 100℃ and 140℃ respectively.
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