These differences become evident in a summary overview of the total PIM process. Binders are, for the most part, mixtures of organic compounds which can include anything from synthetic polymers, like polyolefins, to natural waxes, like beeswax with surfactants and other property-modifying additives. During blending, the surface of each powder particle is coated with binder. After mixing, the compounded feedstock is pelletized for molding. Feedstock can be compounded in-house, or purchased from feedstock suppliers.
Feedstocks are then injection molded, just like plastics.
PIM molding machines are equipped with wear-resistant screws and barrels, and may have any number of special options, but are essentially the same sort of molding machines used to mold plastics. Unlike molded plastic parts, green PIM parts contain binder. A green part is larger than the desired finished part. They are not finished parts right out of the mold. After molding the binder must be removed.