Numerical modeling of powder metallurgy processes

Powder metallurgy (P/M) processes are widely used to manufacture metallic or ceramic net shape parts. In order to help optimize these processes (in particular die compaction, sintering and hot isostatic pressing), CEA-CEREM has developed a computer assisted design and modeling tool named PreCAD®. In the case of hot isostatic pressing (HIP), this tool is used to optimize the design of the initial mould in order to obtain a very accurate part after compaction. In the case of die compaction, it can be used to optimize toolings (die, punches) geometries and pressing sequences in order to: (1) increase parts accuracy and thus limit post-sintering operations (sizing or machining); and (2) decrease the percentage of rejected parts due to the presence of cracks. This tool has been fully validated on real parts in the case of HIP (ISOPREC® process) and is now industrially used. An accuracy of ±50 μm between simulated and manufactured geometries is obtained. Prediction of the relative density is better than 1%. All aspects of PreCAD® are presented in this paper with several industrial examples of applications for the different P/M processes.