The traditional powder metallurgy injection moulding machine has only one set of injection units and can only produce single material products. Powder metallurgy co-injection moulding technology uses powder co-injection moulding machine, which contains two or more sets of injection units. Each set of injection units can inject different materials. It can make parts which composed of different materials. According to the different injection methods, how many types does powder metallurgy injection molding include?

The first is called bi-color co-injection moulding. We inject one material firstly. After it is cooled, the second one is injected onto the first one through a rotating die to form the product. The structural characteristics of the product are layered or mosaic structure. The representative product is ceramic internal gear.

The second is called synchronous co-injection moulding. Two different materials are injected into the cavity at the same time. The structure of the product is characterized by layered structure, such as ceramic heater.

The third is called sandwich co-injection moulding. Two independent injection units are connected through a nozzle. At the beginning, the first material is injected into the mould cavity. Before it is solidified, the second material is injected into the first one. Then, the first material is injected into again to seal the mould. It is a core-shell structure in which the second material is coated like gear parts with core-shell structure.

Powder injection moulding technology provides a new idea for the design and development of functional parts, opens up a new product type and market for the powder injection moulding industry, and is the inevitable trend of the future development of this industry.