Extrusion welding is characterised by the following features:

• A welding additive of the same kind and the same moulding material is used in the welding procedure.
• The extruded and plastified welding additive (extrudate) leaks as a line from a plastifying unit.
• The extrudate is homogeneous and completely plastified.
• The joining layers are heated up to the required welding temperature and plastified.
• The extrudate is spread by a welding shoe and pressed on. That means that the joining procedure is carried out under pressure.