Conical Twin Screw and Barrel
Hot Feed Rubber Machine Screw and Barrel manufacturers take you to understand the role of screw in plastic machinery
Hot Feed Rubber Machine Screw and Barrel manufacturers tell you that the screw is an important part of the injection molding machine. Its function is to convey, melt, compact, stir and press the plastic. All of these are accomplished by the rotation of the screw in the barrel. It can be seen that the role of the screw in plastic machinery is pivotal.
When the screw rotates, the plastic will produce friction and mutual movement between the inner wall of the barrel, the bottom surface of the screw groove, the screw flight advancing surface, and the plastic and the plastic. Hot Feed Rubber Machine Screw and Barrel manufacturers tell you that the forward movement of the plastic is the result of this combination of movements, and the heat from friction is also absorbed to raise the plastic temperature and melt the plastic. The structure of the screw will directly affect the extent of these effects.
At the same time, the rotation of the screw causes shearing of the molten film between the solid bed and the inner wall of the barrel, so that the solid between the molten film and the interface of the solid bed is melted. Hot Feed Rubber Machine Screw and Barrel manufacturers tell you that as the solid bed spirals forward, the volume of the solid bed gradually shrinks and the volume of the molten pool gradually increases.
If the rate at which the thickness of the solid bed decreases is lower than the rate at which the depth of the groove becomes shallow, the solid bed may partially or completely block the groove, causing fluctuations in plasticization, or due to local pressure due to the melting speed of various plastics, the melt Viscosity, melting temperature range, sensitivity of viscosity to temperature and shear rate, corrosiveness of high-temperature decomposition gas, and friction coefficient between plastic particles vary greatly. When the screw is processing some plastics with outstanding melt characteristics, there will be a phenomenon of excessive shear heat in a certain section. This phenomenon can generally be eliminated by reducing the screw speed, but this will inevitably affect the production efficiency.