Using discrete simulations of compaction and sintering to predict final part geometry

Abstract

A Discrete Element Method (DEM) model is used to simulate the compaction and sintering of ceramic oxides. The process kinematics is decomposed into loading, unloading and ejection of the pellet. Interactions between the particles are considered elastoplastic by implementing a model able to tackle large densities. A simplified approach is used in the sintering stage, which focuses on the final part geometry rather than kinetics. The results are in good agreement with experimental data and FEM simulations from the literature regarding density gradient, elastic spring-back and final geometry. The simulations show that the friction coefficient between the agglomerates and the die is the primary factor for the density gradient in the pellet. This density gradient induces non-homogeneous sintering, which results in a final geometry with a diabolo effect. It is the first time that DEM reproduces this effect with the advantage of considering explicitly the particulate nature of the powder.