Powder injection molding (PIM) encompasses metal injection molding (MIM), ceramic injection molding (CIM) and cemented carbide injection molding (CCIM). All three processes combine the attributes of polymer injection molding with the engineering and performance properties of metals, ceramics and cemented carbides. MIM is cost effective in producing complex parts. The ability to mix different powders and binders allows engineering a part having specific thermal, wear, magnetic and strength properties. In addition, the process yields net-shape components requiring little or no secondary operations, which simplifies production, increasing yields and lowering manufacturing costs. A crucial step in the MIM process is to remove the binder used in the formation of the part prior to sintering to the required part density. This article addresses the problems associated with the thermal debind and sinter technology of MIM parts and their solutions.
In the MIM process, fine powders are mixed with various binders to create a thermoplastic feedstock, which can be injection molded. The parts are then debinded and sintered to full density to attain the desired mechanical and physical properties.