Helical extrusion

Helical extrusion technology is applied in the plastic pipe industry. Basically the production process is a direct extrusion. During the pipe production several different materials are mixed in the extrusion unit according to a special formula. The resin (PE or PP) is melted in the main extruder (mostly black material to provide a required UV-resistance of the pipe)and in the co-extruder. In the die head the material flow of the main extruder is divided into two stream, one stream for each of the double dies. The latters produces a two colored continuous strip that is wound in a spiral around a rotating mandrel.