Plastic shaping (extrusion) is the oldest of the three processes used in ceramic manufacturing. The moisture content of the initial body is about 15 % to 25 %.
Ram extruders and vacuum screw extruders are used for shaping. Kneaders used earlier in the process ensure the required plasticity of the initial body and are used to homogenize, de-air and mix the body with suitable organic additives if required.
There are two proven techniques: horizontal and vertical extrusion
Extrusion in particular allows the manufacture of rotation-symmetrical parts such as axles and pipes. Complex profiles are feasible using appropriate nozzle design. The required length of shaped material basically depends on the body’s tendency to warp. The use of suitable manufacturing technologies in the drying process and the selection of adequate organic additives for non-plastic bodies prevent warpage.