SIMULATION OF COLD DIE COMPACTION ALUMINA POWDER

Abstract

Compaction process was analyzed mathematically by predicting a steady-state mathematical model in order to give more description and understanding for the mechanism of this process. Numerical investigation has been carried out on axisymmetric cylindrical parts using the finite difference method with relaxation technique to examine the physical significance of constitutive model to produce the pressure gradients during compaction. The pressure distribution model is then typically coupled with empirical functions relating pressure and density to obtain a green density distribution at all nodes in the green compacts. The model has addressed the influence of frictional forces acting at the powder and die walls interfaces which dissipate the applied pressure throughout the compact. The effect of the compact geometry has a similar effect on the uniformity of green pressure and density distributions through the compact. It was found that a small aspect ratio resulted in a more uniform distribution than a higher aspect ratio. Therefore, the model seems to work better for the lower aspect ratio. The constitutive model predicts accurately the pressure and density distributions during compaction process.