Optimizing press tool shapes by numerical simulation of compaction and sintering - application to a hard metal cutting insert

Designing, manufacturing and commissioning of the tooling often determines the delivery time of a new powder-metallurgical component. To speed-up this process, computer simulations of die compaction and sintering could assist in the development stage. Today, finite element (FE) simulations of the compaction process in combination with appropriate material (or constitutive) laws for the powder allow quantitative predictions of the density distribution in the green body as well as the tool loadings. The shape after firing can be predicted by using an appropriate material law for sintering. The sinter distortions are a result of inhomogeneous density distributions in the green body. These distortions can be minimised by optimum press kinematics, and the remainder can be compensated by appropriately shaped punch surfaces. After presenting an overview about the underlying models and simulation methods for compacting and liquid phase sintering the simulation procedure together with the optimisation technique is demonstrated for a cutting insert made of hard metal powder. Finally, the shape predictions of the liquid phase sintering model are compared with a simplified model.