Simulation of Ceramic Powder Injection Moulding Based on the Behavior of Flow Stress Depended on the Thermal Viscosity Flowage Property and the Volume Fraction

Abstract

The prediction of flow pattern and volume fraction distribution in ceramic powder injection moulding (CIM) is very important because their characteristics affect the mechanical stiffness and the sintering shrinkage. The definition of feedstock behavior in the simulation of CIM depends on the various parameters such as temperature, strain rate and volume fraction. The aim of this study is to generate the governing equation based on non-newtonian flow model and predict the distribution of volume fraction from the result of CIM simulation using the subroutine of finite element package. Material parameters of governing equation are obtained from the compressive test of feedstock. Initial volume fraction is defined as the value of 0.5 referred to experimental data. In the boundary condition, the velocity of injection is 3 mm/s and the frictional coefficient between the feedstock material and the die is assumed as the value of 0.7 which means the value in the condition of cold moulding. The flow pattern of feedstock is very consistent with the experimental result. The result indicates that the range of volume fraction is from 0.42 to 0.58 depended on the pressure distribution. This result aids to predict the material stiffness according to the location of product from the relationship of the volume fraction and stiffness via Micro-hardness test.