Extrusion
Extruding is the oldest of the three named processes in ceramics. Here the moisture of the initial body is some 15% - 25%.
Both piston extruders and vacuum worm presses undertake the moulding. Upstream "kneaders" ensure the requisite plasticity of the initial body. Their function: Homogenizing, deaerating and, if needed, thorough mixing with suitable organic additives.
There are two tried-and-tested possibilities: Horizontal and vertical extruding
The extrusion process is eminently suitable for producing rotation-symmetrical parts such as axles and pipes. But even complex profiles are feasible given the right nozzle design. The strand lengths to be produced essentially depend on the inclination of the body to the warpage. This can be countered by using a suitable drying technique or choosing the right organic additives with non-plastic bodies.
