Tutar and Karakus [6] provided a numerical solution for the 3D modeling of mold insert injection molding by considering the effect of phase-change and compressibility during the filling stage. The results of the flow front evolution from the developed numerical solution correspond well with results from both experiment and simulation by MOLDFLOW software. They have reported that mass flow rate, injection polymer melt temperature, and mold wall temperature influences the polymer flow characteristics, and especially mass inflow rate is the most effective factor. Shen et al. [7] tried to find optimal gate design in injection molding process for thinwalled products numerically and Qiao [8] developed systematic computer-aided approach to achieve the optimal cooling system design in injection molding. Sridhar et al. [9] numerically studied the effect and significance of thermal contact resistance (TCR) between the mold and the vitrifying plastic on heat transfer in injection molding using C-MOLD software. They conclude that TCR is strongly influenced by the gap formation at the interface, and TCR should be treated as both time and space dependent for improving the accuracy of simulation. Park and Ahn [10] performed DOE to find optimal processing parameters in injection molding process using C-MOLD software. They determined optimal mold and process design could increase the productivity and improve the quality of product. Choi and Im [11] numerically predicted the shrinkage and warpage of injection molded products and compared with experimental results to validate the developed model. Chen et al. [12] numerically analyzed the thermal-induced residual stress distribution and related it with processing condition in injection molding. Lee et al. [13] have used MOLDFLOW to simulate injection molding process and analyzed following thermal deformation with ABAQUS to investigate the deformation by in-mold labeling (IML) process. They concluded that thermal impact affects the residual stress of the part considered, thereby determining final deformation. They also found that the thickness ratio is a critical factor influencing the quality of product in IML process.
Many engineering practices, especially mobile industry, utilize injection molding process for their product due to its advantages mentioned before but are known to suffer from the defects associated with thermal deformation. Mobile phone generally has thin shell type structure with relatively high curvature at the corner. The modification to handle the specific problems generated after manufacturing process, still widely executed in industry, would consume lots of time and money. In this study, we developed the numerical model to simulate thermal deformation from injection molding process, especially dedicated to mobile device design, for better understanding of the critical processing parameters on final part quality. In order to improve the accuracy of the predicted result, two commercial softwares, i.e., MOLDFLOW and ABAQUS, were combined to take advantages related to each program. The overall procedure for numerical analysis is to simulate injection molding process with MOLDFLOW and following thermal deformation process with ABAQUS based on finite element method. To validate the developed numerical model, we have compared the results from numerical simulation with experimental ones.
There are numerous variables involved in injection molding process to influence the final part quality and residual stress is generally known to play very important role in geometrical deformation. We tried to separate residual stress by injection molding into flow and thermal-induced stress. Relative importance of flow or thermal induced stress on final deformation has been investigated. Several variables assumed to be critical to residual stress, accordingly final deformation, were selected among numerous processing parameters and DOE was introduced to determine the relative effect of each variable. DOE analysis results could provide various clues to solution if injection molded parts have some problems in dimension or geometry. Likewise, this study aims at not only obtaining the useful tool that can simulate the injection molding process followed by thermal deformation well but also providing helpful resources which can be applied to the initial stage of mobile device design.     注射成型模具设计英文文献和中文翻译(2):http://www.751com.cn/fanyi/lunwen_12455.html