Numerical Simulation Of The Injection Molding For Mobile Phone Shell And Warpage Control

As the integration of function and consideration of portability, the structure of mobile phone shell is becoming more and more complicated, while the wall thickness is becoming thinner and thinner. In addition to the application of various new materials and new technology, the injection molding also becomes more difficult. Therefore, it is significant to introduce the CAE simulation to the design and manufacture of mobile phone shell.Firstly, in this paper the background and the developing situation of the injection molding for mobile phone shell are described and then the common defects of injection molding and their solving methods are introduced. Especially warpage and the effect of injection material, parts design, mold design, process parameters and post processing to it are analyzed.Taking the M2832 bar phone's shell for instance, the impact and the solving methods of the part's material selection and structure design to injection molding are analyzed. Then the filling analysis, cooling analysis and packing analysis are performed using MOLDFLOW to provide references for the later mold design and process parameters selection. To solve the warpage problem of the phone shell in mold trial, the L18 orthogonal experiment table is designed and by MOLDFLOW simulation, the warpage data are obtained under different molding conditions including mold temperature, melt temperature, injection time, packing pressure, packing time and cooling time. The warpage data are analyzed by ANOM and ANOVA to obtain the optimum set of factors and the significance of each factor which shows that the packing pressure and the melt temperature have significant effects on warpage while other factors'effects are ignorable. The warpage under optimum parameters is predicted and verified by a mold trial-run. The result shows the optimum process parameters can be obtained by the combination of orthogonal experiment and CAE simulation.