BMC Injection Molding Based On Automotive Headlamp Reflector

With the rapid development of global industry, the development of die industry has played a very important role in the national economy and also is a sign of social progress. In the1950s, BMC plastics was used as a molding and injection molding material in Europe first, and then it was widely utilized for formed materials in seal part of motor, auto parts, circuit breaker and precision parts because of its size precision, good insulation properties and excellent heat resisting property. Since the1980s, automotive headlamp reflectors using BMC material molding accounts for a considerable proportion to materials, so study on injection molding of BMC mold plastics has important significance to the development of the automotive industry.In this thesis, the automotive headlamp reflector is an object of study, the temperature distribution of the injection mold surface is studied through the analysis of CAE technology, the injection molding process of BMC material is simulated by Moldflow software, and the effects of different process parameters on the products quality are compared in order to guide the actual production and the good surface quality of products is obtained. The main work is as follows.1) A three-dimensional geometric model of lights is built by UG, and a finite element model of headlamp reflector is built for temperature field analysis based on the heat transfer process analysis of injection mold and the heat load and heat transfer boundary conditions are given. It is solved by using the software of ANSYS APDL programming and the mold surface temperature distribution is obtained, which helps to design and arrange the distribution of heating rods and to avoid local overheating phenomenon in a mold. 2) An injection molding process of the reflector is simulated by Moldflow software, and then the heating rods cylinder unit is established and the transient cooling analysis of mold frame is carried out through the new features in Moldflow2013, which makes the simulation results closer to ones in actual test process. The defects in injection molding products are predicted and analyzed.3) On the basis of CAE analysis a test for lamp reflector is done and the problems appeared in the test is analyzed, and then the structure of the mold is modified and the process parameters are adjusted, eventually the optimal injection molding parameters that satisfy the demands of the automotive lamp reflector are determined.