MANUFACTURING APPARATUS AND METHOD FOR PRODUCING A PREFORM

摘要

The present invention relates to a method of forming a preform from a material having a first edge and a second edge utilizing a mandrel. The method comprises the step of extruding the material through an extruder to form an extrudate. The first edge of the extrudate has a configuration complementary to a configuration of the second edge of the extrudate. The method also includes wrapping the material around the mandrel by abutting the first edge and the second edge to form a spiral joint. The invention uses a manufacturing apparatus comprising a multi-screw extruder having at least three intermeshing screws for forming the extrudate. The mandrel receives the extrudate and a pressure-applying device adjacent to the mandrel engages the extrudate and applies pressure to the spiral joint to create a smooth exterior surface of the extrudate and to define the preform.