Head extrusion dies are almost exclusively made of steel at the moment. This is because of manufacturing costs. Steel can be easily shaped in a soft state and does not require any more hard machining after the heat treatment.  
The only viable hard machining processes available would be spark erosion or laser ablation. In addition, large numbers of head extrusion dies are required as a result of what is at times a low number of items produced per die. The main reasons for their malfunction are not only adjustment errors at the press, but also the material that is used and, of course, the design of the die. Figure 1.  
Stress change Fig. 1: Conventional head extrusion die
The material could be improved by substituting tungsten carbide, but the design of the stress change cannot be bettered. The manufacturing costs would, however, be disproportionately high without achieving a major improvement in the number of pieces machined.  
High-performance head extrusion dies resolve both weak points. The press head is made of tungsten carbide and there is no design-induced stress change as a result of the joined design.
 
Fig. 2: Long-life head extrusion dieAt times it has been possible to increase the number of items machined by more than 10-fold.