The Surface Quality Control Of Injection Molding For Dashboard Of Automobile Based On Cae

Warping and welding line are common defects in plastic injection molding process. Especially for large plastic parts, using multi-gate runner will produce the welding line. Nowadays, adopting hot-runner sequence valve technology is the solution of surface welding line in large plastic parts. It’s an effective method to improve the forming surface quality and mechanical properties. And the optimization of injection molding process parameters is also an important method to improve the injection molding quality. For the traditional mold production method relies on repeated trial molding. The staff should have a very rich experience, and the cost of trial molding is also expensive. With the help of CAE simulation software and optimization method, it’s possible to obtain the parameters combination on the basis of optimization index and then guide the practical production.The thesis takes a dashboard as the object to study the surface quality control method of injection molding. Based on the CAE simulation analysis software Moldflow, the mechanism of injection molding welding line and warping on the dashboard are studied. The injection molding structure is introduced according to the structural features of the dashboard; the calculation model for the simulation analysis of dashboard injection molding is established; through the simulation analysis, the injection molding process and the relationship between dashboard panel molding surface quality and warping are researched; and the scheme that can improve the surface quality of the dashboard injection is proposed; using orthogonal optimization analysis method, the runner structure of dashboard is optimized, thus the optimization results of runner structure is obtained. The main research contents include:1. Summarize the research situation about the surface quality of the injection parts at home and abroad, and the necessity of using CAE simulation technology to improve the surface quality is discussed.2. Introduce the injection molding structure according to the structural features of the dashboard. Create the gating system and cooling system adopting the hot runner sequence valve technology. Through the simulation analysis on injection molding process of the dashboard, the thesis discovers that the surface quality of parts and warping do not meet the requirements, and need to be improved.3. Use orthogonal experiment of sequential valve to optimize the design of parts by taking the valve opening time and melt temperature as optimization factors. The thesis uses the scoring method to score on the experimental results to change the non quantitative indicators into quantitative indicators; determine the effects sequence of each factor on the welding line and warping by the range analysis. Adopt the equilibrium analysis method, and obtain the factors combination making two indicators all optimal. The simulation results show that, the surface of parts does not have obviously welding lines, and warping value is also consistent with the assembly requirements.4. Carry out the actual verification test of designed dashboard injection molding. And the results of thesis’s optimization analysis are applied in injection molding process. Test results show that, the surface of parts does not obviously welding lines, and warping measurement results is also within the prescribed assembly scope. It meets the product quality requirements.