The Impact Of Gating System And Products Structure On Melt Flow Behavior Of Injection Molding

With the rapid development of polymer materials, injection molding products are more and more being used in most areas of production."Mechanical precision, products flawless" has become an important development direction of injection molding technology. The accuracy of the injection molding products is affected by many factors, including the performance of the injection molding machine, the molding process and mold structure design, etc. Gating system and products structure are two key aspects of mold design process. They have a critical influence on the melt flow behavior of polymer materials in the filling process, and even the internal morphology of melt. Therefore, the two aspects determine the accuracy of products and the pros and cons of mechanical properties to a large extent.In order to be more specific and in-depth understanding of the impact of these two aspects of products filling behavior on the basis of the existing theory, so as to provide a theoretical basis for improving the accuracy of the products, by means of the visualization experiments and numerical simulation method, the gating system and part of the typical structures of cavity were taken as the research object in this paper, their impact on the melt filling regular had been observed and analyzed. Further more, the quality of products was evaluated from many aspects, including shrink warp, internal stress and mechanical properties, and the impact of various factors on the quality of molding products was ultimately arrived at.The major work undertaken in this study and research achievements are as follows:(1) The impact of the gate on the law of melt filling in precision injection molding was studied from the aspact of gate size and number&location of the gate, etc. Through the comparison and evaluation of the shrinkage, warpage, internal stress, tensile stress of articles under different circumstances, the optimum design was obtained.(2) The influence of different cross-sectional shape and structural layout of the flow channel on the molding process was studied. By comparing the melt temperature pressure drop and loss in different flow paths, as well as the indicators of warpage and shrinkage of the molded articles, evaluation had been made for the different type and structure of the flow channels. It has a certain reference value for practical applications.(3) Experiment was carried out for the investigation of the effect of wall thickness differences and rib structure on the melt filling behavior. Not only dynamically observed the melt flow behavior, but also obtained the generation mechanism of various phenomena and its influence on product performance by means of numerical simulation.