The role of screw in plastic machinery

Screw is the key component of plastic machine, its effect is to carry out transportation of plastic, melting, tamping, mixing and pressure. All this is based on the rotation of the screw in the barrel, it is not difficult to see that the effect of the screw in plastic machinery and equipment is very important.

When the screw rotates, the plastic for the barrel cavity, the bottom edge of the screw groove, the screw edge pushing surface and its plastics and plastics in the middle will cause friction and mutual fitness. The plastic is pushed forward as a result of this exercise composition, and the heat generated by the friction is digested and absorbed to raise the plastic's temperature and melt it. The screw construction will immediately jeopardize this level of efficiency.

At the same time, the rotation of the screw makes the molten film in the middle of the solid bed and the barrel cavity cause cutting effect, and then make the solid melting between the molten film and the solid bed page surface. With the spiral forward change of the solid bed, the volume of the solid bed gradually decreases, while the volume of the bath gradually increases.

If the rate of thickness reduction of the solid bed is less than the rate of deep thinning of the spiral groove, the solid bed is likely to partially or completely block the spiral groove, so that the melting caused fluctuations, Or because of partial pressure because the melting rate of various plastics, solution viscosity, melting temperature category, viscosity sensitive level to temperature and shear rate, corrosion of high-temperature dissolved vapor, friction resistance between plastic particles is very large, In the general practical sense of the general general screw in the production and processing of some of the solution characteristics of the plastic will occur when a section of cutting heat is too high, this kind of situation can be removed according to reduce the screw speed ratio, but this will inevitably harm the productivity.