Numerical Simulation And Optimization In Aspheric Optical Plastic Lens Injection Molding

Injection molding is the mostly used processing technology for all thermoplastic materials and part of thermoset materials. The process of optical plastic lens injection molding is quite complicated because of the character of the material itself and the complexity of processing conditions. For a long time, the control of the injection molding process and the design of the mold mainly depended on the experience of the designers, and the reasonability of the design can only be verified by trial and error. The cycle was quite long and the cost was huge.By Moldflow software, the process can be simulated numerically so that the structure and the property of the part can be predicted and the possible problems can be found at the design stage.In this work , the simulation for the aspheric plastic lens of the injection molding process were tested and their predictions were validated with Moldflow plastics Insight.Moldflow plastics Insight currently uses three differents types of mesh to represent the geometry of a plastic part for analysis.These three mesh types are midplane elements(2.5D),Dual Domain^TM elements(modified 2.5D) and three dimensional(3D) elements.Each type of mesh has its own advantages and limitations. The purpose of this study was to evaluate the filling , packing and warpage simulation results for aspheric plastic lens using Dual DomainTM meshing technique.Through analyzing the results of advance simulation, we can draw a conclusion that tentative process parameters are feasible. Base on these process parameters, warp deflection is simulated, which result shows the most significant factor that effect warp deflection is uneven shrinkage. So in order to reduce the warp deflection, the injection molding process parameters have been optimized by using orthogonal experimental design method.The results of the example indicated that one can considerably reduce the warpage by varying the process parameters.Numerical simulation results are compared to actual experimental moldings of the aspheric plastic lens .It is intended that users of CAE injection molding software tools can use the research presented in this paper as a guide to selecting and using the correct the injection molding process parameters for the the aspheric plastic lens .