Optimization Of Gas-Assisted Injection Molding Based On Taguchi Design

Since it can overcome the defects that conventional injection molding (CIM) cannot be solved:such as sink mark, Uneven shrinkage and so on. the gas-assisted injection molding(GAIM) technology has been widely used. However, the process controls and molding windows are more complex because of more gas processing conditions. In order to make better use of gas-assisted injection molding technology, we need to carry out an in-depth study of its forming principle, molding process and processing parameters. Numerical simulation technology as an advanced design tools in the field of plastic molding processing, especially in the molding of complex molding process. GAIM has been widely used for product design, process parameters selected, mold design, molding quality prediction. However, numerical simulation technology requires a strong professional background. Firstly, based on the existing commercial software, the effect of mesh type and process parameters on the rationality and accuracy of GAIM numerical simulation is investigated, so as to provides theoretical guidance to use the simulation software correctly.1. Brief introduction to the basic principles and classification of gas-assisted injection molding technology, the main advantages and disadvantages of GAIM, molding defects, mathematical models and numerical analysis simulation and so on.2. Discussed the effect of different types of mesh on the numerical simulation of GAIM. In this paper, the spiral tube which was divided into the beam mesh and the midplane mesh and a thin plate designed with a semicircular gas channel which was divided into the midplane mesh and the three-dimension mesh was investigated. Through the result of numerical simulation, the result on the length of the gas penetration using the beam mesh was more accurate than the result which using the midplane mesh, the result of the distribution of hollow core thickness ratio along the gas penetation path of the3D mesh is more accurate than the result with the midplane mesh. The result of3D mesh also can distinguish between the primary penetration and the second penetration.Meanwhile, the result of the midplane mesh cannot.The midplane also overestimate the gas penetration length, but it cost shorter time to build the model and analyse.3. Numerical research on the penetration behavior based on the results of CAE simulation. The gas penetration behavior was described by the gas penetration length. Six processing parameters (including shot size, gas delay time, melt temperature, gas injection pressure, gas injection time and gas packing pessure) are investigated by using Taguchi method to test their effects on the gas penetration length. The influence trend for each paameter is checked one by one.4. The handles had been studied in this work. Five processing parameters (including mold and melt temperature, gas delay time, gas packing pressure and gas injection time) were investigated by using Taguchi method to test their effects on the gas penetration length and the volume of gas penetration. This pages also showed the impact of overflow well on the forming quality.