Principle and application scope of single screw extruder


Ningbo Fangli Technology Co., Ltd. is a mechanical equipment manufacturer with nearly 30 years’ experiences of plastic pipe extrusion equipment, new environmental protection and new materials equipment. Since its establishment Fangli has been developed based on user’s demands. Through continuous improvement, independent R&D on the core technology and digestion & absorption of advanced technology and other means, we have developed PVC pipe extrusion line, PP-R pipe extrusion line, PE water supply / gas pipe extrusion line, which was recommended by the Chinese Ministry of Construction to replace imported products. We have gained the title of “First-class Brand in Zhejiang Province”.



In most extruders, the screw speed is changed by adjusting the motor speed. The drive motor usually rotates at a full speed of about 1750rpm, which is too fast for an extrusion screw. If it rotates at such a fast speed, too much friction heat will be generated, and the uniform and well stirred melt cannot be prepared due to the short residence time of the plastic. The typical reduction ratio should be between 10:1 and 20:1. In the first stage, gear or pulley block can be used, but in the second stage, gear shall be used as much as possible and the screw shall be positioned at the center of the last big gear. For some slow-moving machines (such as twin-screw for UPVC), there may be three deceleration stages, and the greater speed may be as low as 30rpm or less (ratio up to 60:1). On the other hand, some very long twin screws for stirring can run at 600rpm or faster, so a very low deceleration rate and more deep cooling are required.


Structure characteristics and application range of single screw extruder


The screw and cylinder of the extruder are designed based on the building block principle. Its thread shape, cylinder structure, length diameter ratio, number of feeding and exhaust positions, screen changing and pelletizing methods, electronic instrument control mode, etc. can be optimized and adjusted according to the material system and process requirements. It takes into account the unity of multi-function, multi-purpose and specific specificity. It has the characteristics of high productivity and low specific energy consumption.


Scope of application: blending modification (rubber blending, plastic alloy), homogeneity, plasticization, filling modification, granulation. Engineering polymer and glass fiber reinforced. Master batch, functional master batch. Color masterbatch. Special materials, powder materials, oil pipeline coating materials. Reactive extrusion. Various cable materials. Exhaust devolatilization post-treatment.


If you need more information, Ningbo Fangli Technology Co., Ltd. welcomes you to contact for a detailed inquiry, we will provide you with professional technical guidance or equipment procurement suggestions.

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