Optimization Design Of Micro-injection Spline Mold And Research On Cavity Pressure Monitoring Technology

With the development of MEMS, micro-injection molding technology has been widely used in fields of precision machinery, biomedicine, information storage, aerospace because of micro size, high accuracy and suitability for mass production. It is main one of the effective methods of products in MEMS with the constantly increasing demands for micro products. The possible products defects are avoided for mould design by CAE optimization analysis. The control and optimization of the product quality is realized. But the limitations of products are still existed. The melt change process in the mould cavity is unknown in the injection molding process. The cavity pressure is a very important process parameter, it can help the designer making a scientific analysis to the injection molding process by the sensors measured.The micro-injection spline mould and numerical simulation analysis of injection molding process are researched by FEM software in the paper. The best location of sprue of plastic parts is found based on flow analysis CAE software-Moldflow. Three aspects of flow, cooling and warpage of the initial design of the injection molding process were simulated and analyzed. The results of the analysis showed that the warpage of micro-spline. The defects and their molding causes are pointed. The cooling pipes layout and the molding process conditions were optimized and the dwell pressure curve was adjusted to reduce the warping amount of products and meet the production requirements.The molding experiment of micro-spline was carried out by the micro-injection molding machines and the whole process was monitored online using the cavity pressure monitoring technology. It realized the monitoring to the molding process and product quality based on Moldflow analysis. The cavity pressure curves and cavity temperature curves in the actual molding process were studied with the collecting data of cavity pressure. Five injection process parameters, such as melt temperature, mould temperature, packing pressure, packing time, injection pressure were chosen to analyze their relations. The maximum value of cavity pressure and cavity temperature of the tensile spline and impact spline is studied by orthogonal experiment. The process parameters factors with significance are obtained. It can be used to provide guidance in the practical production. The results show that: the packing pressure is a significant factor of affecting the maximum of diverse spline cavity pressure, the mould temperature is a factor of affecting the maximum of diverse spline cavity temperature.