Metal injection moulding (MIM) / Ceramic injection moulding (CIM)
MIM (metal injection molding) is a near net-shaping process technology for the production of complex shaped devices with a high throughput. The main materials used for MIM are hard metals, stainless steels and oxide ceramic powders which can be sintered. It is derived from the well established thermoplastic molding technique and uses fine metallic and ceramic powders.
For MIM technology a small part of a polymer is mixed with a metallic powder. The so called “feedstock” is formed, that can be injected into molding cavities afterwards. The “green part” is formed. With this technology it is possible to obtain very complex geometries with a high reproducibility. After shaping the “green part” the polymeric binder is removed either chemically (with catalytic additives, solvents, water) or by heat treatment. This procedure is followed by sintering, i.e. densification by heat treatment. The sintering process is performed in oxidizing, inert or reducing atmosphere, depending on the powder material used. During sintering, the parts experience a shrinkage between 15 and 22% depending on the powder loading, the used material and the final density. The temperature profiles and the atmosphere during both, debinding and sintering have to be controlled very accurately to avoid distortion and the formation of cracks and bubbles.
Carbolite Gero offers solutions for debinding and sintering of the MIM process. With the GLO annealing furnace the mere thermic debinding can be performed. For catalytic processing tailored debinding furnaces are available to the costumers (EBO). The emerging gases during debinding are burned. Hence, contrary to the products using a condensate trap, the smell nuisance is prevented as well as extensive cleaning steps.
Sintering can be done with the product line HTK, HBO, HTBL at low overpressure, vacuum or in partial pressure. Besides, Carbolite Gero offers special solutions like the partial pressure sintering furnace PDS. With the PDS both (rest) debinding and sintering can be done in one furnace. On demand even debinding is possible in partial pressure mode.