In injection moulding, machine components made of high-quality oxide and non-oxide ceramic materials have proven expedient in those positions in the machine that are exposed to severe mechanical wear and often corrosion too, for example caused by plastics filled with glass fibres or ceramic powders or plastics with readily volatile corrosive components. In injection moulding machines, the plasticizing unit, which consists essentially of cylinder, screw and return flow shut-off valve, is frequently exposed to such stresses.
In the following, typical material data are summarized that are relevant for the use of high-quality ceramic materials in components for injection moulding machines:
- High mechanical and thermomechanical resistance
- High edge stability
- Low tendency to stick to the compound
- High wear resistance and, as a result, minimized ingress of foreign material into the compound
- Naturally, no metallic contamination of the compound
- High corrosion resistance even at elevated temperatures
- Possibility to product ceramic-metal composite components with force-, form- and substance-based joining methods
Compared with those made from metals, components made of dense-sintered, high-purity ceramic materials such as Al2O3, ZrO2, SiC and Si3N4 regularly enable much longer service lifetimes in operating conditions.
Against this background, these materials can also be expediently used for components in equipment for the preparation of injection moulding compounds, such as twin screw extruders and shear roller kneaders, to gain economic advantage.