Simulation Analysis And Experiment Research Of Process In Micro Injection Molding

Along with the micro / nanotechnology rapid development, the application demand of micro parts for various kinds of products in micro mechanical system is growing. However, the conventional micro fabrication technology to mold the micro parts can not satisfied the increasing application demand. Micro injection molding technology can rapidly, economically manufacture micro plastic parts in large quantities and can meet the needs of micro parts in micro mechanical system. 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 very necessary that the new theories and methods of micro injection molding processing need to be set up according to the microscale processing characteristic of micro plastic parts.Contraposing the current application situation and development tendency at home and abroad and using others work as a source reference, we systematically analyze the differences between micro injection molding process and conventional injection molding process referring the interrelated design principles and the theories of molding process for conventional injection mold. Then the micro injection mold with microscale structure features of micro gears is designed and fabricated. On the mold insert, micro gears with 1mm and 2.5 mm pitch circle diameter respectively are made through UV-LIGA technology and micro EDM (Electron Discharge Machining) technology. Accroding to the requirement for molding process of micro plastic parts, simulation analysis of molding process is completed with MoldFlow software, and the influential laws of different process parameters on the filling stage of micro plastic parts are obtained.On the basic of the simulation results, we devise the experiment scheme of molding process for micro gears by orthogonal experiment method, and optimize experiment process parameters. Then the detection indexes and the factor levers are determined. In the light of above theories, the process experiments for investigating the effects of single factor and interactive function of factors are done, and the overflowing micro plastic gears is attained .The experiment results show that the effects of process parameters on the molding process of plastic part are distinct different between micro scale and macro scale. Melt temperature, injection rate and holding pressure are the main factors to molding micro parts. These results have actual instructional significance for the production of micro plastic parts.