abstract (from A. Burblies, G. Grecksch and J. Massinger (2002), Int. Conf. Process Modeling in Powder Metallurgy)

Finite element simulation of warm compaction process compared with experimental results

The present paper summarizes the results of a combined experimental and numerical analysis of warm powder compaction. The process of warm compaction allows the production of high density green parts in a single uniaxial compaction step. In order to simulate the process, specific material data of the warm compaction powder and a constitutive model are needed to show how material properties change with pressure.

The numerical simulation is based on the Drucker-Prager/Cap model. Axial pressure and strength tests have been carried out in order to determine the density dependent model parameters. For the axial pressure tests, an instrumented warm compaction tool was developed which exhibits the possibility to measure the axial pressure at the punches and the radial pressure at the die wall during densification. The friction between powder and die wall and the green density distribution were determined experimentally. As a result of finite element simulations, the density and stress distributions in the green parts during the warm compaction process can be obtained. The calculated densities are in good agreement with the measured density distribution of manufactured green parts. Based on the Drucker-Prager/Cap model, the warm compaction process can be simulated correctly.