Materials for Powder Injection Molding (PIM)

PIM encompasses both metal injection molding (MIM), based on metallic powders, and ceramic injection molding (CIM), based on ceramic powders; the both processes are nearly identical in practice.

A typical PIM process, here assuming the use of a metallic powder (MIM) as an example, proceeds as follows.

First, the metallic powder is blended with a binder (plastic + wax) to yield a uniform mixture, which is compounded into feedstock with good formability properties. The pelletized feedstock is then molded by an injection-molding machine, just like typical plastics. The resulting molding parts are heated and treated with solvents, catalysts, and other agents to remove binders, then finally sintered in a furnace to yield high-precision metal components. The molding parts obtained immediately following injection molding contain some concentration of binder resins, but these components are eliminated by the binder-removal and sintering steps, ultimately producing metallic bodies with complicated three-dimensional shapes similar to that of plastic injection molding.

PIM is a processing technique capable of addressing a broad and expanding range of needs, including the production of precision instruments, electrical and communication devices, automotive components, and medical devices. PIM essentially forms metallic components via the same procedure used to manufacture plastics and has the following key features.

Resins used as PIM binders must satisfy several practical requirements.