Processing Parameters And Filling Behavior In Micro-injection Moulding Products

Micro injection molding process is one of the core technologies in microinjection molding technology, and it not only provides the technical guarantee butalso the technical gist to verify forming theory and the design of the micro injectionmould. However, due to the miniaturization of the structure and size in the microinjection molding products, the melt flow characteristics showed different die fillingin the micro channel compared with macro dimension channel, which makes thetraditional injection molding process parameters setup is no longer suitable for microinjection molding, so studying on micro injection molding process characteristics, toget clear melt flow state in the micro cavity and the regularity of filling of the microinjection molding products on processing and application has a very importantsignificance.This paper investigates the micro cylindrical array of the isotactic polypropylene(ipp) products with considering microstructure product dimension, construction andmicro injection molding process characteristics on the design of the micro injectionmolding products model and mold, effects of the mold temperature, injection speed,melt temperature on the filling quality of the microstructure of injection products andoptimizing its molding process, furthermore, examined the micro cylindrical flowfront in the process of filling evolution and its filling performance of microcylindrical array products under different injection velocity. Work and conclusionsare as follows:1. Designed the micro forming die of cylindrical array products. Mould wasadopted the combination of the main structure and set piece of structure mode, and"sandwich" structure design was used in the set piece of micro cylindrical regionwhich not only increasing the exhaust ability of the micro cavity, and improving thefilling performance of micro injection plastic products. Moreover, the CAEtechnology was used to optimize the gate location and gate size of mold.2. Based on the orthogonal experiment design method, effects of the moldtemperature, injection speed and melt temperature on forming quality with different feature sizes of micro cylindrical array products are examined. The poor analysis andvariance analysis results are basically identical. Process parameters on the furthestaway from the gate line of micro cylindrical average filling height index rule is:injection speed> melt temperature> mold temperature; the influence law of thetrimming on cylindrical surrounding is: mold temperature> injection speed and melttemperature. The optimal process parameter setup is: the mold temperature is80℃,the injection speed is400mm/s and the melt temperature is280℃.3. The filling behavior of micro cylindrical array products under differentinjection velocity using the single factor experiments is investigated. The resultsshow that "higher in the middle and lower on both sides, one side is higher than theopposite side" trends on micro cylinder filling rendering of the recently a row of thedistance runner, furthermore, the melt flow front "eccentric" phenomenon are worsewhen the melt are filled into the cylindrical cavity from micro macro dimensioncavity with increasing the injection speed.