Compaction and sintering of a ceramic seal: Modeling and experimental response

The delivery time of a new powder-metallurgical component is controlled by the tooling design, manufacture and commissioning. Cracking of the part in the production process must be avoided, and close geometrical tolerances are often required. Further, excessive wear and fracture of tool components must be prevented. Thus, the commissioning of a new tool is often a time-consuming process. A faster alternative to the conventional method of trial and error is to optimize the whole process by computer simulation. Finite element simulations of the compaction process in combination with appropriate material laws for the powder allow quantitative predictions of the density distribution in the green body as well as the tool loadings. Finally, the shape after firing can be predicted by using a material law for sintering. The sinter distortions are a result of inhomogeneous density distributions in the green body. The distortions can be minimized by optimum press kinematics, and the remainder can be compensated by appropriately shaped punch surfaces. All this is demonstrated for a complex three-dimensional part m ade of Al2O3 powder