Screw plays an important role in plastic machinery

  • Detail

Screw plays an important role in plastic machinery.

screw is an important part of injection molding machine. Its role is to transport plastic, further summarize and exchange innovative scientific and technological achievements in the field of non-ferrous materials in recent years, and use the achievements to melt, compact, stir and apply pressure. All these wire pulling machines are completed by the rotation of the screw in the barrel. It can be seen that the screw plays an important role in plastic machinery

when the screw rotates, the plastic will cause friction and mutual movement on the inner wall of the barrel, the bottom surface of the screw groove, the screw edge pushing surface, and between the plastic and the plastic. The forward movement of plastic is the result of this combination of movements, and the heat generated by friction is also absorbed to raise the temperature of plastic and melt plastic. The structure of the screw will directly affect the degree of these functions

at the same time, the rotation of the protective shell and shell of the screw manufacturing mobile equipment makes the molten film between the solid bed and the inner wall of the barrel shear, thus melting the solid between the molten film and the solid bed interface. As the spiral shape 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 rate at which the depth of the screw groove becomes shallow, the solid bed may partially or completely block the screw groove, causing plasticization to fluctuate, or due to the local pressure, the melting speed, melt viscosity, melting temperature range, the sensitivity of viscosity to temperature and shear rate, the corrosion of high-temperature decomposition gas, and the friction coefficient between plastic particles vary greatly due to the melting speed, melt viscosity, melting temperature range, viscosity sensitivity to temperature and shear rate of various plastics, In the general sense, when processing some plastics with outstanding melt characteristics, ordinary general-purpose screw will have the phenomenon of excessive shear heat at a certain section. This phenomenon can generally be eliminated by reducing the screw speed, but it will inevitably affect the production efficiency


Copyright © 2011 JIN SHI