Main parameters of the 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”.


Screw refers to the metal rod with screw groove that can rotate in the barrel of extruder or injection molding machine. Screw is the most important part of extruder to transport solid plastic, plasticized plastic and melt, which is often called the heart of extruder. Through the rotation of the screw, the plastic in the barrel can move and get pressurized and friction heat. The geometric parameters of the screw have a great relationship with the characteristics of the extrusion machine. Whether the screw design is reasonable or not directly affects the working performance of the extrusion machine.


Below we briefly introduce some main parameters of the single screw extruder for reference:

· Screw diameter: refers to the outer diameter of the screw, expressed in D, in mm

· Screw length diameter ratio: expressed in L / D, where L is the length of the working part (or effective part) of the screw, that is, the length of the threaded part (L is the length from the center line of the feeding port to the end of the thread)

· Screw speed range: expressed in nmin ~ nmax, refers to the screw speed per minute. nmin refers to the lowest speed, nmax refers to the highest speed, in rpm (or R / min)

· Screw compression ratio: generally refers to geometric compression ratio, which is the ratio of the volume of the first screw groove in the screw feeding section to the volume of the last screw groove in the homogenizing section, expressed inε

· Screw helix angle: with Ф Indicates the included angle between the tangent of the helix and the plane perpendicular to the thread axis on the pitch diameter cylindrical surface

· Drive motor power: expressed in N, unit: kW

· Extruder productivity (output): expressed in Q, refers to the weight of plastic products produced by the extruder per hour, unit: kg / h

· Nominal specific power: expressed in P, it refers to the comprehensive index of electric power required for processing 1kg materials per hour.

That is, P = n / Qmax, unit: kW / (kg / h)

·  Specific flow: expressed in q, refers to the weight of plastic products produced when the screw works for one revolution. It can reflect the production efficiency of the extruder. Q (kg / h) is the measured value. N (R / min) is the measured corresponding speed, i.e. q = Q measured / n measured, in (kg / h) / (r / min)

· Machine center height: expressed in H, refers to the height from the screw center line to the ground, unit: mm


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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