The screw of the injection molding machine is to convey, heat, compacting, melting, stirring, exhausting and extruding plastic. The choice of screw for injection molding machine is mainly to select the ratio of screw length to diameter -L/D. L is the effective length of the screw thread part. The larger the diameter of the screw, the larger the length diameter ratio of the screw, the longer the length of the screw, the direct influence of the heat course in the material in the screw, and the ability to absorb the energy. If the L/D is too small, it directly affects the melting effect and the melt quality of the resin; if the L/D is too large, the transfer torque increases and the energy consumption increases. . DKM injection molding machine screw diameter ratio is between 17 and 22, often using 20:1 or so.