MIM Overview

Metal injection molding (MIM) Overview

Metal injection molding (MIM) is a development of the traditional powder metallurgy (PM) process and is rightly regarded as a branch of that technology.

The standard PM process is to compact a lubricated powder mix in a rigid die by uniaxial pressure, eject the compact from the die, and sinter it. Metal injection molding (MIM) is a metalworking process by which finely-powdered metal is mixed with a measured amount of binder material to comprise a “feedstock” capable of being handled by plastic processing equipment through a process known as injection molding. The idea to plastify powdered raw materials with the help of thermoplastic additives and subsequently use injection molding to form complex components was first developed for ceramic components.

The molding process allows dilated (oversized due to binder) complex parts to be shaped in a single step and in high volume. After molding, the powder-binder mixture is subjected to steps that remove the binder (debinding), Subsequent conditioning operations are performed on the molded shape, where the binder material is removed and the metal particles are diffusion bonded and densified into the desired state with typically 15%-20%(depends on materials) shrinkage in each dimension. Finished products are small components used in various industries and applications.