Ansys-based Powder Injection Molding Filling Process Simulation

The control equations and boundary conditions for the die filling process of powder injection molding are proposed, by assuming that feedstock melt is a non-Newtonian and incompressible continuum-flow on the basis of the theories of hydromechanics and thermodynamics. The finite element analysis software -ANSYS was used to solve the equations and to simulate the die filling process.Taken the tensile bar as an example, the die filling process of cemented carbide feedstock was simulated. The effects of flow rate, injecting temperature and the gate location on the die filling process were discussed and the conditions for the appearance of some defects in compacts were predicted based on the simulation results. The results show that good green compacts of cemented carbide could be made in the condition of volume flow rate of 61cm3/s ,die temperature of 300K and the injection temperature of 420K, and with lateral injecting gate, which was proved by the experiments.Finally, the molding process of a product with complicate shape was analyzed with the developed simulation technique. The obtained results were similar to those obtained with the commercial software Polymold by Crocher et al, which verified the feasibility of our model and math methods. Based on the simulation results of melt front, temperature and pressure fields, the conditions for some defects appearing in the compacts were determined. The process for selecting injection parameters based on the simulation results are introduced.