Most plastic products after injection molding is the finished products which can be assembled and shipped. However, for MIM, injection molding is only the first step, followed by degreasing, sintering, shaping and other complex processes. These complex processes prevent many people who want to enter MIM industry. But those plastic companies that have already entered or are ready to should fully understand the differences between injection moulding and MIM.

First, the understanding of feeding:

In MIM process, the only function of plastics is that they act as a carrier to bring metal powder into the cavity through injection, and form the parts we want by cooling.

Usually we use plastic as the binder in the feed, and its volume is about 40% of the whole part. What specific ingredients are there in the binder?

A, Wetting agent, make the surface of metal powder humid, which can reduce the tension of the interface between binder and powder.

B, A macromolecule component. When degreasing, it is removed first, and form a network of voids, so that other binders are more easily decomposed.

C, Skeleton polymer. After degreasing, it is used to maintain the shape of the parts until the temperature rises to the sintering temperature.

D. Another material that mix the main binder and the skeleton polymer. According to different metal powders, various kinds of feeds can be produced, such as low alloy steel (iron-nickel), high alloy steel (stainless steel series), carbide (tungsten carbide-cobalt), non-ferrous metal (titanium, copper), precious metal (gold), magnetic metal (neodymium-iron-boron), etc. The size, distribution and shape of these powders affect the feed flow.