Study On Warpage Behavior Of Unbalanced Filling In Multi-cavity Injection Molding Products

Injection molding is an important method of forming plastic products. It can produce complex shape, high precision products. To improve the manufacture efficiency, multi-cavity injection molds are usually employed to produce the plastic products. However, obviously un-balanced flow phenomenon will appear in the production process when we use a multi-cavity injection mold, which causes the quality difference of the plastic products. In injection mold-ing production, warpage is one of the most common quality defects. Unbalanced filling will lead to the inconsistent warpage values of the plastic part.The shape of the warpage deviation caused serious influence quality of the product.In in-jection molding production, the inappropriate setting of the process parameters will result in warpage and some other undesirable quality and defects. The influences of each parameter on product quality are also different. Therefore, the analysis of warpage deformation and the opt-imization of molding conditions are very effective measures to improve product quality. For the warpage phenomenon of the sliding pin parts’injection process, do the following work:(1) Design a mold structure of the plastic slide pins parts, including the design of the gat-ing system, core, cavity, guides, positioning mechanism, demanding mechanism and cooling systems, etc. Then set up its three-dimensional model in UG software. Using the Moldflow/MPI analysis software, meshing of the injection mold and pre-treatment analysis has been carried on. Production testing has proved the accuracy and usability of the model.(2) Taguchi test methods have been used to analyze the quality of the plastic parts. Sum-med up the molding conditions’effect on the trend of the test,and get the molding condition combinations which can make the maximum warping value reach the minimum and make each cavity reach the robust optimal warping value.(3) This paper analyzes the warpage’s difference between the far and near cavities and the internal difference of4points in single cavity, and analyzes and summarizes the general law of deformation in the sliding pin injection molding process. Based on imbalance filled caused by Non-balanced arrangement of the gating system, using Beaumont theory to analyze the problem, which considers that it’s the shear heating that lead to the deformation between the cavities and each cavity internal.In conclusion, this paper try to use Beaumont theory on the warpage analysis, it has some reference value in the future of research; and the results of optimization of the product of molding conditions have the guiding significance on production practice.