Ceramic Injection Molding (CIM) How does it work ?
Axial pressing, Cold isostatic pressing (CIP), Hot Isostatic pressing (HIP) are the common methods used for the manufacture of rough near net-shape formed parts which need to be achieved to the net shape by a machining with diamonds tools, drastically increasing the production cost.
CIM is a powder injection molding : a combination of injection molding and sintering science which allow the achieve complex shapes of very hard materials that are costly, difficult or impossible to form using the traditional shaping processes.
The main steps are :
The steel mold, with the cavity to shape the part are designed and machined with cad-cam technology.
Ceramic powders are blended with organic binders and additives to get the feedstock.
The feedstock is injected into the mould cavity, similar to plastic injection to get after cooling the called "green part" when plastic injection molding finish there, the Ceramic injection molding needs additional steps.
A special treatment is made to remove by evaporation, exothermic or chemical reactions the organic binders from the green part.
The debinded part is heated, the component shrinks and densify up to near the theoretical density (99.8%) and meets the final required dimensions and tolerances. On demand a heat treatment under high pressure (HIP) is applied to reach the theoretical density ( > 99.99 %)
Polishing, Grinding, or Machining
"Adamou Sàrl of Etoy, Switzerland, is using ceramic injection moulding (CIM) to produce a sintered valve seat from 99.9% alumina powder."
Featured in: Powder Injection Moulding International magazine