Question:
I have one question regarding powder-metal products, its complexity to press, sinter and bringing it into final shape according to different specifications. Can you evaluate if MIM can substitute the before mentioned process? I have some market indications which tell me a new technology will and maybe can substitute the pressing/sintering/machining process.I would like to know your expertise.

Answer:
Pressed and sintered parts that require extensive machining after sintering could be replaced by parts made by the powder metal injection moulding (MIM) technology. I could go on for pages comparing the two processes, but here are a couple of features that compare press and sintered parts with parts made by MIM that should pique your interest:

Press and Sinter Technology

1. Uniaxial pressing limits shape.
2. Densities of the parts are limited to about 92% maximum because of the powders used and the use of lower sintering temperatures. This results in poorer physical and mechanical properties.

Powder Metal Injection Moulding Technology

1. Injection moulding permits 3-dimensional features including internal and external threads. Parts made from multiple components may be replaced by a single component molded part.
2. Densities obtained are usually better than 96% and typically better than 98% with the porosity uniformly distributed. This results in physical and mechanical properties close to wrought products and better than cast products.

Costs are of course of prime importance when comparing processes, in which case the part would have to be redesigned to take advantage of the features of MIM. Rand German’s “Powder Injection Molding – Design and Applications” (published by Innovative Materials Solutions, Inc., State College, PA, 2003, ISBN 0-9727642-0-8) provides excellent insight to designing for MIM.