Formation Mechanism Analysis Of Sink Mark Defects And Parameters Optimization Of Injection Molding Process For Air-conditioning Plane Frame

Air-conditioning plane frame surface defects is considered greatly in the process of the injection molding, and how to control the formation of the air conditioning plane frame surface sink marks is gradually become a hotspot of research at home and abroad. the paper aimed at an enterprise problem at the production process which the sink marks is appear in the air-conditioning plane frame surface, non-newtonian fluid mechanics, heat transfer, modern design theory, numerical analysis and finite element analysis theory and method is used integratly, the formation mechanism of air-conditioning plane frame sink marks defects and the optimization methods of injection molding process parameters are discussed. In the paper, the main research work is as follows.(1) Firstly, the background is introduced in this paper, It is clear about the important significance of the mechanism analysis of air-conditioning plane frame sink marks defects and the optimization of injection molding process parameters, the theory and the application of injection molding, the formation mechanism and control of sink marks, the optimization of injection molding process parameters is oriented quality, which are carried on the induction and summarizes related the research work at home and abroad. the main research contents and the overall mentality are given.(2) The research of sink marks formation mechanism for air-conditioning plane frame. It is Combined air-conditioning plane frame production process, the injection molding process parameters, the structure of plastic parts, mold structure and material selection is deeply analyzed, the formation of sink mark defects and evolution mechanism are obtained. And the four steps of air-conditioning plane frame injection molding process are combined: plasticizing, filling, packing and cooling, the mathematical modeling is built for the sink marks formation of air-conditioning plane frame, the changes of pressure force field, the changes of the temperature field and the changes of thermal residual stress, and the measures to reduce sink marks defects is presented.(3) The numerical simulation of air-conditioning plane frame injection molding process. According to the flow field, the proper gating system is built, and according to the air-conditioning plane frame structure and the cooling flow channel layout principles, the cooling flow channel is designed. Finally, according to the above work, the air-conditioning plane frame geometric model of numerical analysis is established in the Moldflow software, and the scheme of original parameters setting is checked, the original scheme sink mark index of air-conditioning plane frame and related moldflow analysis results are obtained.(4) The impact analysis of air-conditioning plane frame injection molding process parameters. Based on Moldflow numerical analysis, the influence law of sink mark index and five parameters such as melt temperature, mold temperature, the relative packing pressure, injection time and packing time is obtained, and through the analysis between influence law of packing time and sink mark index, good pressure effect and the shorter packing time are obtained.(5) The optimization of injection molding process parameters and experimental validation for air-conditioning plane frame. Based on the regression orthogonal combination experiment, the main injection molding process parameters that influence the sink mark index of air-conditioning plane frame is analyzed, the response surface model between the air-conditioning plane frame sink mark index and the main injection molding process parameters is established, and the constraint conditions of various process parameters is set up, the objective optimization function for the minimum sink mark index is established, the best air-conditioning plane frame process parameter combination and the smallest sink mark index value are obtained. Finally, based on the numerical simulation experiments and injection molding experiments, which validate the best process parameter combination sink mark index reach the expected goal, the sink mark depth of air-conditioning plane frame injection products surface is shallow, the process requirement is reached.