| As the rapid development of MEMS technology, the application demand of micro parts for various kinds of products in micro mechanical system is growing. But as structure dimension and volume of micro plastic parts is extremely small, the conventional and macroscopic injection molding processing theories and methods have lost the guiding significance. So, it is necessary that the new theories and methods of micro injection molding processing need to be set up according to the characteristic of micro plastic parts.First the current research of micro injection molding at home and abroad is introduced in this thesis, then according to the basic theory and process of conventional injection molding, simulation analysis on molding process of micro-gear which is molded with three types of polymer including POM is completed with Moldflow software. Based on the simulation result, effect of process parameters on quality of micro parts is studied by orthogonal experiment. The order and contribution rate of every experiment factor on target index is determined by means of range analysis and ANOVA analysis respectively. The experiment results show that as POM and PP is molded, mold temperature and melt temperature are the main factors to filling rate of micro-gear and the sum of their contribution rate is over 70%. For micro injection molding, mold temperature should be around 100℃ and melt temperature should be 50℃ higher than their melting point. But injection pressure and injection rate have little influence on filling rate. While ABS is molded, melted polymer can not be filled in the micro-gear cavity under any parameters group from the orthogonal list. This result shows that ABS which is considered as good fluidity polymer in conventional injection molding is not suitable for micro injection molding.The experimental research on micro-gear injection molding can be a valuable reference for further study of basic principle and applied technology of micro injection molding.
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