| Injection compression molding processes is a advanced type of plastic manufacturing technologies compared with injection molding process. Low residual stress and low injection press can be realized with this technologies. Due to this advantages of injection compression molding, it is increasingly possible to substitute the injection molding processes in case of optical product. Polycarbonate (PC),one of the commonly used transparent thermoplastic engineering plastics, has excellent impact resistance and good light transmittance. Due to this advantages, it is wildly used in aerospace and automotive, home appliance and so on. When it comes to producing the PC products, the traditional injection molding method usually induce many defects, such as large Warping deformation and large residual stress. However, injection compression molding can solve the above problems very well. During the injection compression molding process, there are many factors which can affect product quality performance, such as the product structure design, mold design, material performance and the combinations of process parameters. In these factors, the affect of combinations of process parameters is remarkable. In order to get excellent quality product, we have to adjust the combinations of process parameters. But it is difficult to adjust only by the experiment since it require numerous case studies as well as much time and cost. In order to reduce such efforts and expenses, computer simulations for injection compression is utilized in this paper. Computer aided engineering analysis has supported useful research in the molding processes with better efficiency.The effect of process parameters on PC product in injection compression processes is studied by using the design of experiment (Taguchi DOE) and numerical analysis. DOE is designed and applied progressively for process design. The results can provide certain reference for the industrial injection compression process of PC products. The main work and conclusions are as follows:(1) Firstly, the product mold is set up by CAD software and then the finite elim-ent model of the feed system and cooling system is built by moldflow software. Based on this, the injection compression simulation of PC product is done to confirm the correctness of the model. The injection compression molding simulation and traditional injection molding are done under the same conditions. Compared with the result s of the two methods, the results show that a better PC product with low warping deformation, low residual stress and uniform shrinkage can be got by injection compression.(2) The effect of processes parameters on the Z component warping deflection and the residual stress is investigated by using the Taguchi design of experiment and numerical analysis. The processes parameters include melt temperature, mold temperature and compression distance and compress delay time and so on. Then the analysis of means(ANOM) is performed for various process conditions in order to determine the optimum combination of process parameters. The analysis of variance (ANOVA)is applied to identify the influence degree order of the process parameters for the two test indexes. The results show that the influence degree order for the two test indexes is same, but the effects of various process parameters on the two test index are at different levels. Among the various process parameters, the influence of melt temperature, compress delay time and compression distance is the most significant. In order to further study the influence of the main three process parameters, the single factor analysis is utilized on the basis of the optimum combination of process parameters. The results show that the residual stress near the gate location is gradually reduced with the increase of melt temperature, the decrease of compression distance and delay time. When it comes to the Z component warping deflection of the PC product, it will reduce with the increase of melt temperature and compress delay time, but it will increase with the increase of compression distance.(3) On the basis of orthogonal experiment, the fractional factorial experiment is designed to investigate the two-way interactions of the main process parameters. The results show that the effect of the two-way interactions of the main process parameters on the two test index factors is different, but the interaction between the compress delay time and the compression distance is the most important factor.(4) With the same design of experiment method and data processing method, the effect of processes parameters on the Z component warping deflection and the residual stress of three kinds of injection compression molded products with the same volume and different curvature is investigated. The results show that the effect order of process parameters for each product is different and melt temperature is the most important factor. With the increase of curvature, the effect of melt temperature is also increase. In addition to the melt temperature, delay time and compression distance also have significant effect. |
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