Metal injection molding (MIM) is very suitable for high-precision manufacturing of complex metal parts on which strict demands are made, such as high dimensional accuracy and long service life. MIM is evolved from plastic injection molding and offers the same benefits, namely a very great freedom in the design and production of (medium to large series. We can find MIM parts, for example, in car engines, smart mobile phones, door locks and surgical instruments. As the series becomes larger, so MIM becomes more attractive, because then the costs of the tooling (that can be as high as 20 K) can be spread over the series.
During metal Injection molding, metal parts are produced in four steps. The base material (feedstock) 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%. Metal parts 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 without secondary machining. But the most important benefit of the technology for FineMIM is that we can manufacture extremely complex metal parts that are not possible – or are very expensive – by machining. That is also possible by metal 3D printing, but that technique becomes less suitable when the series becomes larger. So anyone who thinks that MIM was the predecessor of metal 3D printing is wrong. Metal injection molding remains relevant – today and in the future.