Effects of particle characteristics on homogeneity of green bodies in powder injection moulding
Effects of particle characteristics on homogeneity of green bodies in powder injection moulding
复制标题
粉末注射成型中颗粒特性对生坯均匀性的影响
DOI：
10.1179/1743290114y.0000000101
复制
发表时间：
2014-09-01
影响因子：
1.4
通讯作者：
Qu, X. H.
中科院分区：
文献类型：
--
作者：
Fang, W.;He, X. B.;Qu, X. H.
在粉末注射成型(PIM)中，粉末和粘结剂在坯体中的均匀分布是至关重要的。本文基于多相流体理论、喂料粘度模型和粉末-粘结剂阻力模型，建立了注塑成型充型模型。颗粒雷诺数受颗粒大小和密度的影响，导致粉末和粘结剂之间的阻力不同。此外，通过对连续性方程的数值计算，得到粘结剂和粉末的速度变化，从而导致坯体均匀性的变化。利用CFX软件对注射成型充型过程进行了数值模拟。结果表明，坯体的均匀性与填充方式有关，不同的粉料密度不同，填充方式也不同。当颗粒尺寸大于20μm时，粉末不宜用于注射成型，而细粉有利于改善注射成型的均匀性。
A homogeneous powder and binder distribution in the green body in powder injection moulding (PIM) is important. In the present study, the mould filling model of PIM has been developed, based on the multiphase fluid theory, viscosity model of feedstock and powder-binder drag force model. The particle Reynolds number is influenced by the particle size and density, resulting in the different drag force between powder and binder. Furthermore, the varied velocity of binder and powder will be obtained with numerical calculation of the continuity equations, leading to the change of green body homogeneity. CFX was used to simulate the mould filling in PIM. The results showed that the homogeneity of green bodies was relative to the filling patterns, which varied with different powder densities. The powders were not suitable for PIM when the particle size was bigger than 20 μm, and the fine powders were beneficial to improve the homogeneity.