Development of an industrial device of blend/filling of heterogenous powders

L. Federzoni (a), M.L. Penaud (a), S. Revol (a), O. Dauchot (b), F. Daviaud (b)
a CEA-Grenoble, DTEN/STN/LT2N, F38054 Grenoble cedex 9
b CEA-Saclay, DSM/DRECAM/SPEC, l’Orme des merisiers, 91191 GIF on Yvette

Abstract

In many industrial fields -- as varied as pharmacy, food, powder metallurgy, ..., the handling of powders or blends of powders is a stage impossible to circumvent during which many difficulties can occur. In particular when it is a question of filling a die by materials finely divided prior to a compression stage, it is very difficult to ensure the transport and the deposition of powder in a controlled, homogeneous and fast way. The situation is even more delicate when one wants to use a blend of powders : at each stage of the process, and in particular during the discharge in the die, segregation may occur. The finer the powders, the more difficult it will be to avoid difficulties. In powder metallurgy, many components are manufactured by the compaction of metal powders obtained by chemical synthesis or atomization means. The powders are deposited in a cavity or die presenting the form which one wants to give to the component. The powder is then compacted under high pressure, and the green parts thus obtained are then sintered.

We have developed a device which ensures the homogeneity of the density distribution of the powder in the die. In addition, our device allows to preserve the composition homogeneity in the case of an initially prepared blend of powders. When two separate batches of powders are used, we show that the blending operation can be carried out simultaneously with the filling.