What Aspects of Ordinary Screws Need to Be Improved?

Screw and barrel are the central components of plastic molding equipment. It is the heating, extruding, and plasticizing part, and the center of plastic machinery. Extruder screws are widely used in machining centers, CNC machines, CNC lathes, injection molding machines, wire cutting, grinders, milling machines, slow wire feeding, fast wire feeding, PCB drilling machines, engraving machines, engraving and milling machines, spark discharge machines, gear biting machine, planer, large vertical lathe gantry milling, etc. The screw is an important part, and its function is to transport, melt, compact, stir and press the plastic.


All of these are accomplished by the rotation of the extruder screw in the barrel. It can be seen that the effect of the extruder screw in plastic machinery is very important.


Ⅰ. When the extruder screw is rotating


There will be friction and mutual movement between the plastic and the inner wall of the barrel, the screw, the bottom surface of the screw groove, the screw edge advancement surface, and the plastic and the plastic. This combination of motions drives the plastic forward and the heat generated by friction is absorbed to raise the temperature of the plastic and melt it. The structure of the extruder screw will directly affect the extent of these effects, so the extruder screw design is crucial.


At the same time, the rotation of the extruder screw causes the melt film between the solid bed and the inner wall of the extruder barrel to have a shearing effect, thereby melting the solid at the interface between the melt film and the solid bed.


Ⅱ. The influence of the rotation of the extruder screw on the solid bed


As the spiral of the solid bed moves forward, the volume of the solid bed gradually decreases, while the volume of the molten pool gradually increases.


If the thickness of the solid bed decreases at a rate lower than the speed at which the depth of the screw groove becomes shallow, the solid bed may partially or completely block the screw groove, causing fluctuations in plasticization. Perhaps because of local pressure and the melting speed of various plastics, melt viscosity, melting temperature, sensitivity of viscosity to temperature and shear rate, and corrosiveness of high-temperature differentiation gases, the friction coefficient between plastic particles varies greatly.


When processing some plastics with outstanding melt characteristics, the general purpose extruder screw will have a certain section of excessive shear heat. This phenomenon can generally be eliminated by reducing the extruder screw speed. But this is bound to affect production efficiency.


As a professional screw and barrel manufacturer, we specialize in producing parallel and co-rotating modular screw elements, barrels and screws, covering various models from Ø20mm to Ø300mm. After ten years of vigorous development, our company now has a number of advanced CNC machine tools and special processing equipment for screw manufacturing. Now our machining operations have basically realized intelligence and automation.


Advanced processing methods, strong technical force, and sophisticated processing technology ensure that the quality and technical indicators of each production fully meet customer requirements. If you have any needs, please feel free to consult us.

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