Numerical simulation of powder volume fraction variation during powder injection molding filling flow process

The variation of powder volume fraction during powder injection molding filling flow process was simulated based on the two-fluid model. The region in which the serious separation between powders and binder occurs was visually observed in the three-dimensional distribution graph, and the industrial CT was used to verify the results. The results indicate that the simulating variation of powder volume fraction can be obtained with this method. The serious separation between powders and binder occurs in the region of die wall, vertex, and area below the inlet in the sample, leading to non-homogeneous shrinkage during sintering, and these regions need to pay more attentions. As the increase of the injection rate, the volume of low fluctuation region increases firstly, and reaches a maximum value when the injection rate is 70 cm3/s, then decreases. The change trend and fluctuation range of the distribution curves of powder volume fraction are fitted with the CT test results, so the reliability of simulating results is demonstrated