What Are the Main Methods to Improve the Plasticizing Quality of Extruder Screw?

The main method to increase the output of the extruder is to increase the screw speed. However, while increasing the rotational speed and the output, it often brings about the decline of plasticizing quality and the increase of fluctuation. In order to ensure that the plasticizing quality of the extruder screw remains unchanged, the main measures currently taken are as follows:

1. The extruder screw adopts shearing element

To improve the plasticizing quality of the extruder screw, shear elements such as barrier heads should be used. When the melt flows through the small gap, energy conversion is promoted by shearing action to accelerate the melting of the plastic. The barrier prevents the passage of unmelted plastic and ensure plasticizing quality at high rotational speeds.

2. Use a new type of extruder screw

To improve the plasticizing quality of the extruder screw, a new type of extruder screw mainly based on mixing elements such as split pin screw, DIS screw and slotted screw should be used. By disrupting the material flow, changing the streamline position and mixing the liquid and solid phases, the purpose of promoting the pulverization and refinement of the solid phase can be achieved to accelerate the melting. It can achieve the purpose of transferring heat to the solid phase to reduce the average temperature of the extrudate. It can also achieve the purpose of uniformly mixing each group of melts to reduce fluctuations.

Relying on the screw thread of the additional extruder, the melted phase is separated and guided away in time. During this process, the unmelted solid phase is fully contacted with the hot barrel to accelerate its melting process. The separated type extruder screw is designed according to this principle.

Through the continuous change of the size and shape of the cross-sectional area of the extruder screw flow, the plastics can be kneaded, rolled and divided, so as to achieve the purpose of strengthening mixing and promoting plasticization. The variable-flow screw such as the wave screw is designed according to this principle.

To improve the plasticizing quality of the extruder screw, when the plastic is melted, the temperature of the melt should not be increased as much as possible. The main method is to reduce the shear rate of the molten material and the heat transfer area of the molten material in the high temperature barrel. Both the melt trough screw and the XLK screw are designed according to this principle.

3. Design extruder screw system reasonably

By reasonably designing the feeding area of the screw and barrel, a high pressure is established on the screw as soon as possible, so that the melting point is advanced due to the advance of the compression point, which accelerates the melting of the plastic. The establishment of high pressure also improves delivery efficiency and reduces pressure fluctuations. The IKV system is designed according to this principle.

In terms of production specifications, LESUN not only provides general extruder screws and standard twin screw extruder accessories produced by manufacturers, but also provides design and manufacturing services for special extruder accessories according to customer requirements. At the same time, we also provide surveying and mapping business and processing business of accessories for major extrusion press companies. If you are in need, welcome to contact us.

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