Melting Mechanism Of The Grooved Single Screw Extruder

Based on the study on the positive conveying mechanism in the grooved single screw extruder (SSE), a novel shear melting model was established by combining the compression grooved barrel and the anti-compression BARR screw. The solid was melted efficiently mainly by the shear friction heat. A new clamshell type barrel SSE platform with a grooved feed zone and melting zone was constructed. The melting mechanism in the SSE with a grooved melting zone was investigated. The main results of our work are summarized as follows:1. Based on the novel combination of a compression grooved barrel and an anti-compression BARR screw, a novel melting mechanism named as Groove-Channel Coupled melting mechanism was established. The melt starting point and the melting lengths in the SSE were solved. According to the new melting mechanism, the effects of structural parameters of the grooved barrel and screw, physical parameters of the material and the processing parameter on the melt starting point and the melting lengths in the SSE were theoretically analyzed.2. A conventional SSE, an IKV SSE with spiral grooves in the feed zone, and a Groove-Channel Coupled SSE were constructed according to the Groove-Channel Coupled melting mechanism. A new clamshell type barrel SSE platform was established, with which the melting of the solid in the SSEs can be monitored in time.3. The experiments on the melting of the three different SSEs were carried out and the following results were gained:(1) The melt starting points and the melting lengths in the Groove-Channel Coupled SSE are stable with different screw speeds and close to the theoretical melt starting point with high screw speed.(2) Benefiting from internal frictional heat generated by the efficient shear melting system, the solid in the Groove-Channel Coupled SSE can be melted with low barrel temperature close to the material melting point.(3) The melting efficiency was able to fulfill the need of the high solid conveying efficiency of the Groove-Channel Coupled SSE. The differences between the experiment throughput of the Groove-Channel Coupled SSE and that of the grooved feed zone are small.