A high density is a prerequisite for making high strength PM components. By increasing the density, both strength, and in particular fatigue strength and ductility are improved. 

To achieve high density one of the key issues is to use as low amount of lubricant as possible in order to increase the theoretical density to which the mix can be compacted. However, the lubrication must be efficient enough to eject the pressed part from the tool without deteriorating the surface of the part due to friction. Insufficient lubrication may also lead to damage of the press tool.

Warm die compaction is a process route that is increasingly used for production of high density PM components. By heating the tool die the efficiency of the lubricant will be enhanced, thus allowing a lower amount of lubricant to be used.

Efficient lubrication does not only influence the ejection of the part but also the overall density, as well as the density
distribution inside the pressed component. Lower friction during the compaction results in less density gradients in the pressed part. 

In this paper results are presented from measurements of the lubrication during the compaction. The results include different lubricants and how heated tool die influences the lubrication as well as density of the parts.