Feed section screw groove depth. Depth h1, it can accommodate more materials, increase the supply amount and plasticizing capacity, but it will affect the plasticizing effect of the material and the shear strength of the screw root, usually h1=(0.12~0.16)ds. L3 - Length of melting section. A fuse is also known as the homogenization section or metering section, the melt is further homogenized in the spiral groove of the L3 section, the temperature is uniform, the composition is uniform, and the melt quality is formed.

L3 length is conducive to the fluctuation of melt in the screw groove, has the effect of stable pressure, so that the material is evenly extruded from the screw head, so it is also called the metering section. L3 short time, help to enhance the plasticizing ability of the screw, generally L3=(4~5)ds. h3 - melt section spiral groove depth, small h3, shallow spiral groove, can improve the plasticization effect of plastic melt, conducive to melt homogenization, small injection molding machine but h3 too small will cause high shear rate, shear heat is too large, resulting in molecular chain degradation, affecting melt quality; On the contrary, if h3 is too large, the backflow effect generated by the back pressure of the screw during the pre-molding process will reduce the plasticizing ability.