| Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 91 === Abstract
Micro-injection molding is characterized by high mold temperature to avoid freeze-off during filling. However, the high mold temperature will prolong the cycle time and reduce the productivity. In order to raise the mold temperature and reduce the cycle time, developing a system for rapid mold heating and cooling is the first objective of this study. The rapid mold-heating and cooling system used in this study is heat pipe heating and water cooling. To find the best design parameters for arranging heat pipes and water cooling channels, numerical analysis was carried out. After the proper design Parameters were found, micro molds were constructed. Three mold materials, including mold steel & beryllium copper alloy and aluminum alloy were used to compare the influence of mold material on the cycle. The results showed that the to cool from 180℃ to 50℃ is 15 seconds, and then to heat to 180℃ is 37 seconds for mold steel. The times of cooling and heating are 24 and 51 seconds for beryllium copper alloy, and are 18 and 43 seconds for aluminum alloy.
Micro-injection molding is used to mold micro plate parts with micro-features on both surfaces for optical or other functions. The second objective of this study is to study the moldability of micro plate parts with micro-grooves on both sides. The results showed that the capacity of replication is the same as that moldability of the plate for micro-grooves with low aspect-ratio. High mold temperature is found to reduce molecular orientation effectively.
|
|---|
