Abstract: The conveying section of three types of single screws of extruders for poly(lactic acid) was simulated by using Polyflow. The mixing performance of the three types of screws was analyzed by taking the flow path of the 24 mm reference line of the screw axis. Under the same process conditions, the axial melt velocity on the common type and pineapple-like screws was relatively large, a local recirculation region was formed which was not conducive to the transfer of the melt. The pineapple-like screw had high flow velocity and viscosity, so that the uniformity of the material was continuously improved in the flow field in order to obtain a higher shear rate, so the dispersion of the extrusion product was better. In extrusion process, the viscosity of the melt was consistent with the change of the flow velocity, and the shear action of the melt increased with increasing flow velocity, which led to the decrease of viscosity and the increase of the flow velocity.

Key words: Single screw extruder, Melt conveying section, Simulation