FEM Numerical Simulation On Temperature Field Of Injection Molding In Cooling Stage

Cooling is playing a very important role in polymer injection processing, and affects molded product quality, cost and cycle time. Meanwhile temperature is one of the most important parameters in injection molding process. Improper cooling channel and temperature parameter will not only influence cycle time but also result in quality problems, such as appearance flaws, dimension accuracy, residual stress and warpage deformation, decreased service performance and so on. When precision molded parts and Hi-tech productions as optics lens and Biochips are made, the issue of cooling and temperature is more significant which need more attention to temperature controlling and temperature changing. Therefore, many study and research focuses on temperature field of cooling stage during injection molding cycle.Traditional cooling simulation mainly utilizes heat transfer and numerical method based on 2D plane numerical method, including mid-plane model and fusion model. Mid-plane model is used for thin parts or some productions with relative simple geometric structure, but it is very difficult to build a mid-plane model for a complicated production. Fusion model needs a very high match ratio, and calculation precision is hard to control which lead fusion model difficult to be used widely. Nowadays, true 3D Solid technology is a trend in numerical simulation of polymer processing. Although 3D Flow simulation with advanced technology is popular, especially in the fields of IC (Integrated Circuit) and MEMS (Micro-electromechanical Systems), cooling and warpage simulation are still based on 2.5D model in current software. Thus, this paper mainly discusses the 3D temperature field of injection molding.In this thesis, the concept of "material boundary" is introduced to simplify the governing equations, and 4-node tetrahedron element of 3D model is used to simulate temperature field. Based on "material boundary", both mold base and polymer part have same heat transfer equation except different material thermo properties, and boundary conditions reduces 2 coupled equations compared to that of the tradition methods which can obtain mold temperature field and polymer part temperature field synchronously by one calculating.The finished jobs are as follows:...