The series Arc uses a barrel in two parts: A grooved barrel sleeve with a length of 3-6D and a smooth barrel with approximately 25D. These extruders appeared in the beginning of the year 1980. They should achieve a higher flow volume with the same diameter of the screw. In general they are longer than the extruder with a smooth barrel and they are linked to screws so called barrier screws. Due to the fact that they are less universal than the extruders and coextruders of the series Elipse, the machines of the series Elipse are mostly used for Polyolefine (PE and PP) as well as for soft material (soft PVC, TPE). The grooves can be straight (in the axis of the machine) or generally helical.