Ceramized Injection Moulding Machine for Contamination Free Preforming

Abstract

Ceramic injection moulding is normally performed in conventional moulding machines. The machine parts subject to wear are made of wear resistant alloys in order to achieve acceptable machine life. Even so, the worn off material is enough to contaminate the ceramic compound and generate critical defects in the ceramic end product. Such contamination will limit the strength and reliability of ceramic products.

Defects caused by worn off material were virtually eliminated by substituting the steel parts of mixing and moulding machines in contact with the moulded material with ceramic parts. The screw, cylinder, valve and sprue bushing were made of silicon nitride and the inlet parts of polymer materials.

The design of the machine is described. An evaluation of the machine was made by comparing tensile test results of moulded rods from the conven tional machine and the ceramized machine.