The process involves continuously extruding molten thermoplastic material into a weld preparation on the plastic component or structure which is being joined. The extrusion barrel on the extrusion gun is heated along its length, either by cartridge heaters or hot air. A thermoplastic rod or granule feedstock is fed into the rear of the extrusion barrel and the material is heated as it is drawn through the barrel by the rotating extruder screw. The ejected material is shaped to match the profile being welded, and defines the shape and size of the final weld. At the leading edge, hot gas is used to ensure there is sufficient heat in the substrate material to form the weld. Typical welding speeds are 0.5-1.0 m/min. Extrusion welding is generally used to weld custom fabrications with sheet, nozzles etc.
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