【摘要】 根据由金属注射成形喂料特性得出的流变本构方程和数学与物理模型,分析了金属注射成形充模流动的特性,并与塑料注射成形进行了对比。结果表明:基于连续介质模型的数值模拟方法可以应用于金属粉末注射成形流动前沿、温度场、应力场等参数的计算,从而可以预测焊缝、缩孔和裂纹等缺陷的产生条件,但连续介质模型无法预测粉末注射成形特有的两相分离和粉末密度分布不均匀的现象,造成模拟结果在某些方面往往和实际情况有较大的偏差,影响实际运用效果。因此,颗粒模型和两相流理论将是金属粉末注射成形计算机过程模拟的重要研究方向。更多还原

【Abstract】 The mold flowing and filling characteristics of PIM feedstock are compared with those of the plastics. The research is carried out using theological formulations and mathematical and physical model based on the characteristics of MIM’s feedstock. The results indicate that the continued medium model can be used to calculate the flow fronts, temperature and pressure fields, which can be used to predict the conditions resulting in welded seam, shrink cavity and cracks in compacts during molding, process. However, the continued medium model can not predict the separation between solid powder and binder melt during flowing and filling, which results in non-uniform density distribution of the compacts. So it will make more differences between the research and the reality. Therefore, the granular model and two-phase flowing theories will be the key problems to be solved for the computer simulation of PIM process.更多还原