PE pipe production extrusion principle

extrusion principle

The plastics processing industry is a highly comprehensive technology-based industry.

It involves polymer chemistry, polymer physics, interface theory, plastic machinery, plastic processing molds, formula design principles and process control, etc. Extrusion theory mainly studies the movement and changing rules of plastics in the extruder. Under the action of external force in the extruder, the relationship between the three physical states of the high polymer in different temperature ranges, the structure of the screw, the properties of the plastic, and the processing conditions. So as to carry out reasonable process control. In order to achieve the purpose of improving the output and quality of plastic products. When plastic polymer materials are heated under constant pressure, they will appear in three physical states: glass state, high elastic state, and viscous fluid state in different temperature ranges. Generally, the molding temperature of plastic is above the viscous flow temperature.

The rotation of the screw produces shearing force to break the plastic; the rotation of the screw produces a driving force to make the broken plastic advance continuously and thus generate extrusion pressure; under the action of extrusion pressure, the filter plate and other parts where the pressure reaches produce a reaction force ( That is, back pressure), resulting in the flow and stirring of plastic, so as to achieve the overall balance of the extrusion process. This process is exactly the condition and sufficient condition for plastic to achieve uniform plasticization.