In order to shape a component, the material is normally melted and then cooled in a mold. Sintering permits to shape parts without having to heat the material to its melting point. In this process, metal powder, partly with additives such as waxes, is compressed in dies to form green parts which are then sintered at temperatures below the melt point. As a result, the powder particles coalesce or merge at their interfaces, and consolidate to give the parts their final properties.
Sintered parts can have a density of up to 98%. After a final cold-upsetting step, they exhibit high dimensional accuracy. The process is suitable only for parts of very simple geometry. It is also limited in terms of weight and size of the parts to be manufactured. Otherwise, inconsistent process behavior can occur during sintering.
Metal powder is produced by means of water atomization. Fast cooling results in a spattered powder capable of mechanical interlocking during subsequent compression.
Powders are mixed in the ratio of the desired alloy.
Several plungers are used to compress the powder in dies to form green parts.
The green parts are sintered and thus compacted at 70% to 80% of the melting point of the alloy.
Final cold-upsetting eliminates even the smallest inaccuracies and enhances the dimensional precision of the parts.