Gas-assistant extrusion molding device

Abstract

A gas-assistant extrusion molding device comprises an extruder, a gas control system and a gas-assistant extrusion molding die; during the extrusion molding process of polymer melt, a stable gas cushion film is formed between the inner wall of the extrusion die and the extruded melt, and thus the frictional resistance between the die wall surface and the extruded melt is reduced; therefore, the extrusion swelling phenomenon during the extrusion molding process is basically eliminated; the die pressure drop is reduced; and the surface quality problems of 'sharkskin', extrusion rupture phenomenon, and the like are prevented in the extrusion molding process.

Description

technical field [0001] The patent of the invention belongs to the field of polymer extrusion molding. Through a gas control system and a gas-assisted extrusion molding die, the polymer melt is formed between the inner wall of the extrusion die and the extrusion melt during the extrusion molding process. Stable air cushion film layer, thereby reducing the frictional resistance of the die wall facing the extruded melt. Background technique [0002] Extrusion molding has become one of the basic molding methods in the polymer processing industry due to its advantages such as many changes, wide uses, high production efficiency, low investment, and continuous production. About 40% of polymer products are formed by extrusion processing. Molding plays a pivotal role in polymer processing. However, the traditional extrusion molding has the following problems: 1) Extrusion swell, extrusion swell refers to the phenomenon that the cross-sectional size of the extruded product is larger ...

AI Technical Summary

Problems solved by technology

However, the traditional extrusion molding has the following problems: 1) Extrusion swell, extrusion swell refers to the phenomenon that the cross-sectional size of the extruded product is larger than the size of the extrusion die, and the extrusion swell increases the difficulty of the design of the extrusion die and affects Product precision

2) The pressure drop of the extrusion die is large. Due to the high viscosity of the polymer material, a large die pressure is required to overcome the resistance of the inner wall of the die to the extrudate during extrusion, resulting in a large pressure drop of the die, so that the extruded product Increased stress, resulting in increased deformation and also increased energy consumption

3) Defects in the surface quality of the extruded product. When the extrusion speed exceeds a certain limit, "shark skin" and extrusion cracks appear on the surface of the extruded product. The appearance of surface quality defects in the extruded product limits the increase in the extrusion speed , affecting production efficiency

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