Simulation And Optimization Of Process In Injection Molding For Tir-r Lenses

TIR-R high gain concentrator is used in concentration photovoltaic system. The concentrator is a combination of a primary lens and a secondary lens with complex structure, which requires a very high optical efficiency. The reasonable mold design and optimization of process parameters in injection molding of the lenses are very significant to reduce the manufacture error of lenses.In this thesis, on the basis of studying the basic theory, the numerical simulations of injection molding process for the primary lens and secondary lens were carried on using CAE software. The main contents studied in this thesis are as follows:1) The basic theory of injection molding was studied. The theory of injection molding processing and the basic parameters involved in the process were first discussed in detail, and then the mathematical models in this process were studied in detail including the fill and flow models, material properties models and cooling process models.2) The geometrical models for the lenses were established by Matlab and pro/E software. By taking account of the structure and the desired optical performance of lenses, the structure and shape of the injection mold's pouring system and cooling system was designed. Through the simulation of injection molding process for the lenses and analyzing of the simulation results, the optimized size of every structure was confirmed and coolant temperature was selected. Ultimately the reasonable mold design of the primary and the secondary lenses was realized.3) For the TIR lens, Taguchi experimental design method was used, L27 table for five parameters including packing pressure, packing time, injection time, melt temperature and mold temperature, and considering the interaction of packing pressure and packing time. Range analysis method was used to analyze the test data. The affection of the parameters on the warpage and shrinkage behavior of TIR lens was discussed. The parameters were optimized combined with the actual production process. L16 experiment was designed, and the optimized parameters were obtained, but the result is not as good as the one of L27. The effectiveness and accuracy of Taguchi experimental design was proved, but it was showed that the result of optimization is related with selection of the levels.4)By using the method of artifical neural networks, the prediction model of warpage and shrinkage behavior of the lenses was established. Through training, this model could well reflect the quantitative relationship between the process parameters and the TIR lens warpage and shrinkage.