The function of the extrusion machine is to accept the prepared clay and form it to the required shape. Normally, the clay is fed to the top section of the extruder where the final mixing of the clay is done. The clay is then compressed and shredded before falling through the vacuum chamber where air is removed, thus making the clay much harder, tougher, improving the end product. After de-airing, the clay is compressed into a strong mass and extruded as a continuos column.