How to Improve the Dimensional Accuracy of Plastic Profile Forming Process

Plastic profiles are widely used and used in many occasions. They are also indispensable in industry. How to improve the dimensional accuracy of plastic profiles?

The outlet pressure of extruder fluctuates greatly under the influence of various factors, which will affect the dimensional accuracy of profiles.

If we install a melt pump between the extruder outlet and die head, it can be used to stabilize the pressure fluctuation at the extruder outlet and make linear extrusion possible, thus improving the dimensional accuracy of plastic products and increasing the output of the extruder in unit time.

Melt pump is a kind of positive displacement conveying equipment. The design of high precision gear clearance and volume structure makes stable and balanced extrusion possible. It has been widely used in chemical fiber, granulation, plastic film, sheet, sheet, profile, pipe, wire and cable, wire drawing, compound extrusion and other production lines, and has achieved relatively good results. Effect:

1. It can achieve stable extrusion, improve the dimensional accuracy of extruded products and reduce the rejection rate. In the extrusion process, the phenomena of uneven material feeding, temperature fluctuation of barrel and nose, and fluctuation of screw speed are unavoidable.

Using the melt gear pump can eliminate the feeding error of the feeding system, greatly reduce the fluctuation of upstream process transmission, quickly enter a stable working state, improve the dimensional accuracy of extruded products, and reduce the rejection rate.

2. Increase output, reduce energy consumption, achieve low temperature extrusion, prolong the life of the machine. Because the polymer melt pump is installed in the extruder, the decompression function of the extruder is transferred to the gear pump to complete. The extruder can work at low pressure and low temperature. The leakage flow is greatly reduced and the output is increased.

Gear pump is more effective than extruder in establishing die pressure, reducing back pressure of extruder, reducing the axial force of screw and prolonging service life.

3. It has linear extrusion characteristics and is convenient for the coordination of upstream and downstream equipment. Because the leakage flow of gear pump is less, the transmission capacity of the pump is basically linear with the rotational speed. When the rotational speed of gear pump changes, its flow can be exactly known.

Because the synchronous working speed of upstream and downstream equipment and gear pump can be determined, the pressure and temperature information collected at the inlet and outlet of gear pump can be used to realize on-line monitoring and feedback control of the whole extrusion process.