When is powder metal the optimum process?
17 Jan. 2017
Due to its high ductility, stainless steel is suitable for metal working, whether within forming, cutting or joining.
Typical metal working processes are drawing, stamping, casting, cold forging and powder metallurgy.
Drawing and stamping involve sheet metal working, and in particular stamping has the advantage of allowing for production of many workpieces in a very short time. On the other hand, the possible complexity cannot be compared to neither traditional powder metallurgy – nor MIM (metal injection moulding), for that matter – both of which offer an incredible freedom of design in metal. A clear advantage of drawing is a much greater hardness, whereas the disadvantage of both drawing and stamping is increased tool costs.
As regards complexity, the 3D design opportunities of casting are comparable to MIM, but with lower start-up costs, as casting tools are typically cheaper than MIM ones. On the other hand, casting often requires post-processing, involving extra and often expensive processes.
And it is typically when two or more processes are involved that powder metallurgy is truly competitive. The design opportunities in powder metal are far superior, porosity may be a material property advantage, and the process involves minimal waste – typically only 2-3%.
Cold forging offers smooth surfaces, if this is required, but subsequently, the material is less ductile. Furthermore, working with details and not least fine tolerances throughout the workpiece is difficult, and cold forging often requires post-processing.
Powder metallurgy does not offer the same smooth surfaces as cold forging, but better surfaces than e.g. casting. In addition, it is possible to work with extremely fine tolerances within powder metallurgy.
In short, the choice of process is often complex, and the optimum process naturally depends on the application and requirements. Our experts are always ready to offer advice.