Length of a plasticizing section (compression section). The material is continuously compressed, filled and mixed in this conical space, the material starts from the entry point of L2 segment, the molten pool continues to increase, and the molten pool has become a full spiral tank when the exit point, the material has completed the transformation from the glass state through the viscoelastic state to the viscous flow state, that is to say, this section of plastic is in a state of coexistence of particles and melt. Too long L2 will affect the transformation process of the material from the glass state to the viscous flow state of the small injection molding machine, and too short solid material will form a large pressure, viscous flow or axial force at the end of the L2 section. Too long L2 will increase the viscous flow of the screw and unnecessary consumption, in general, too long L2=(6~8)ds. For crystalline plastics, the melting point of the material is obvious, the melting range is narrow, L2 can be shorter, generally (3 to 4)ds, and for heat-sensitive plastics, this section can be longer.

The size of the pitch affects the spiral Angle, so the top ten injection molding machine brands are the transmission efficiency of the spiral groove, usually S=ds. Gamma - compression ratio. ε=h1/h3, that is, the ratio of the feed groove depth h1 to the melt groove depth h3. Increasing ε can enhance the plastic effect, but it will weaken the plastic ability, in general, ε is slightly smaller, which is conducive to improving the plastic ability and increasing the adaptability of the material.