Basic structural parameters of the screw, the basic structure of the screw is mainly composed of the effective screw length L and the connecting part of the screw.

The outside diameter of the S-screw and the diameter of the screw directly affect the plasticizing ability, that is, the size of the theoretical injection volume, so the screw diameter of the injection molding machine with the larger injection volume is also larger. l/ds- Length to diameter ratio of the screw. The effective length of the screw is L, the larger the length-diameter ratio of the screw, the longer the length of the screw, which will directly affect the heat conduction process of the material in the screw and affect the energy absorption capacity of the material, and the energy absorption process has two parts: Part is the cylinder external heating ring, the other part is the friction heat and heat conduction heat generated when the screw rotates, which is converted from the external mechanical energy, therefore, L/ds will directly affect the melting effect and melt quality of the material, but if the L/ds is too large, it will increase the transmission force and consume more energy. L1 - Length of charging section.

The feeding section is also known as the conveying section, in order to improve the conveying capacity, the surface of the screw groove must be smooth, L1 length should ensure that the material has enough conveying length, because L1 is too short will lead to premature melting of the material, so it is difficult to ensure the stable pressure conveying conditions, and it is difficult to ensure the plasticizing quality and plasticizing ability of the screw after the section. Under the action of its own gravity, the plastic part slides into the spiral groove by the hopper, the injection molding machine is pressed into the dense solid plug nut under the friction of two different stress surfaces composed of the barrel and the spiral groove, and the relative movement along the direction of the force is carried out, in this section, the plastic part is in a solid state, that is, the glass state.