The possibilities of MIM


The possibilities of MIM

My nephew came home after five lessons in soapstone sculpture with a self-made little doll that I was able to recognise – with a little effort – as a dwarf. The little doll reminded me of the dwarf, Dopey, that I used to make as a plaster figurine when I was a child. I poured the plaster into a rubber mould and waited three days before I could peel the rubber off the hardened plaster. It was a relaxing hobby, all the more so since I found the plaster figurines prettiest in white and never painted them.

My dear nephew: If you want to make complex figures, machining is a good but very laborious solution that also has its limits. The (injection) moulding of material can be a very attractive alternative. It has even been possible to shape metals by injection moulding for about thirty years using a method called metal injection moulding (MIM). Menzing frequently employs this advanced technology to have series of complex parts made. It has a number of leading suppliers in this field.

Metal injection moulding (MIM) is very suitable for high-precision manufacturing of products on which strict demands are made, such as high dimensional accuracy and long service life. MIM is evolved from plastic injection moulding and offers the same benefits, namely a very great freedom in the design and production of (medium to large series. We find MIM products, for example, in car engines, closing systems for fire doors and surgical instruments. And in the machines that Menzing develops for its clients. As the series becomes larger, so MIM becomes more attractive, because then the costs of the mould (that can be as high as 60 k) can be spread over the series. During metal Injection moulding, metal products are produced in three steps. The base material consists of metal pellets produced from metal powder and plastic powder. The metal powder can be steel, but can also be stainless steel, titanium or tungsten. The pellets are heated to 160˚C and then injected into a die. Debinding of the plastic now takes place at the same temperature. The product is then sintered at a temperature of 1400˚C. Sintering gives the product its final format. It shrinks by up to 20%. Products weighing from 0.1 gram can be produced in this way. The dimensions of the product are very precise (max. 0.25% deviation from the final dimensions).


From the moment that larger quantities have to be produced, MIM is a very inexpensive production technique. Another important benefit is that there is no material loss, as there is with machining. But the most important benefit of the technology for Menzing is that we can manufacture extremely complex products that are not possible – or are very expensive – by machining. That is also possible by 3D printing, but that technique becomes less suitable when the series becomes larger. So anyone who thinks that MIM was the predecessor of 3D printing is wrong. MIM remains relevant – today and in the future.

Martijn Geerdink |
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