Molding control device of circular bar extruder and control method

Abstract

The invention discloses a molding control device of a circular bar extruder and a control method. The molding control device comprises a mouth die molding device and a process parameter control system; a gas-aid-free section mouth die of the mouth die molding device is provided with a melt parameter testing port, a mouth die gas inlet cover plate is provided with a lubricating gas flow measurement port, and a gas-aid mouth die and a gas-aid mouth die jacket are provided with lubricating gas pressure and temperature measurement ports; and the process parameter control system comprises a melt parameter control device and a lubricating gas parameter control device. The method comprises the steps of inputting a lubricating gas and implementing melt parameter control and lubricating gas parameter control. Extrusion molding is converted into an approximately full slippage non-adhesion extrusion mode from a non-slippage adhesion extrusion mode and the plastic melt is extruded in a plunger piston state in a flow passage so as to realize the reduction of extrusion pressure, save energy consumption, basically eliminate off-die expansion, improve product precision, reduce material waste, shorten the molding period and save the cost.

Description

technical field [0001] The invention relates to a polymer material forming processing equipment, in particular to a forming control device and a control method of a circular bar extruder. Background technique [0002] When extruding traditional round rods, non-slip adhesion shear die extrusion is often used, that is, the molten plastic melt directly contacts the inner wall of the die, which increases the melt flow resistance. At the same time, the process parameters adopt open Ring control system, that is, temperature and pressure control are only carried out before the melt enters the molding extrusion head, and the real melt state of the molding die section is not monitored and controlled. Due to the high viscosity and viscoelasticity of the polymer melt, Therefore, there are the following disadvantages in molding: [0003] 1. Extrusion swelling is easy to occur: extrusion swelling increases the difficulty of extrusion die design and affects the accuracy of composite pipe...

AI Technical Summary

Problems solved by technology

[0002] When extruding traditional round rods, non-slip adhesion shear die extrusion is often used, that is, the molten plastic melt directly contacts the inner wall of the die, which increases the melt flow resistance. At the same time, the process parameters adopt open Ring control system, that is, temperature and pressure control are only carried out before the melt enters the molding extrusion head, and the real melt state of the molding die section is not monitored and controlled. Due to the high viscosity and viscoelasticity of the polymer melt, Therefore, there are the following disadvantages in molding:

[0003] 1. Extrusion swelling is easy to occur: extrusion swelling increases the difficulty of extrusion die design and affects the accuracy of composite pipes;

[0004] 2. The pressure drop in the flow channel of the extrusion die is large: the internal stress of the extruded composite pipe increases, resulting in increased deformation and increased energy consumption;

[0005] 3. Surface defects of the extruded product: Because the extrusion speed exceeds the critical extrusion speed of the material, the phenomenon of "turtle skin" and extrusion cracking on the surface of the product, the appearance of surface quality defects of the extruded product limits the extrusion speed. Improve, affect production efficiency

[0006] The above three problems seriously affect the precision of products, limit the increase of extrusion speed, and lead to high energy consumption of extrusion.

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