During the extrusion process of thermoplastic plastics can be divided into three phases.
1.plastic raw materials, plastics, in the rotating compaction and mixing extruder barrel temperature and screw down, change the powdered or granular plastics into viscous fluid substance.

2.the forming, viscous flow state of plastic melt in the extrusion screw force push, and get the section and shape of die continuous profiles consistent through the die with certain shapes.

3.the type, by proper processing methods, such as sizing processing, cooling treatment, which has been extruded plastic continuous curing for plastic profiles.