Automotive interior sheet extrusion machine

Back - also known as reflux, its direction of flow positive flow of the whole good contrast. It is due to head in a mold, sieve, and filters and other plastic hinder the forward movement of the pressure generated in the region where the nose (plastic forward reaction force) caused. Charging port by the head to form a "reflux under pressure", also known as "back-pressure flow." It causes a loss of productivity. 3) cross-flow - it is the direction of the axis, that is threaded with plastic grooves perpendicular to the flow direction. Is pushed by the rotation of the screw is formed. Its flow is a screw groove sidewalls resistance, resistance due to the interaction of both sides of the thread, and the screw is in the rotation, the plastic producing rolling motion in the screw slot, an annular flow, so the essence of cross-flow circulation. Circulation of mixed plastics in the barrel, and plastics into a molten state, and it is inseparable from the role of circulation. Circulation so that the material produced by stirring and mixing in the barrel, and the barrel is conducive to heat exchange and material, it is important to improve the quality of meaning out, but the impact on the extrusion flow rate is very small 4) leakage current - it is also by the head of the mold, sieve and filter resistance generated. But it is not the flow of the screw slot, but in the screw and barrel gap formed in the back. It can also cause loss of production capacity. Since the gap between the screw and barrel is usually small, so under normal circumstances, the leakage current flow more positive than the small stream and back. In the extrusion process, the extrusion will affect the amount of leakage current, the leakage flow increases, the amount of extrusion will be reduced. Four plastic flow state is not a separate form, on a plastic particle, it can be neither true back, there will not be a closed loop. Melt plastic thread groove of the actual flow is a comprehensive state of the four flow to a helical trajectory forward flow. 5. The quality mainly refers to extruded plastics extrusion quality plastic case is good, geometry is uniform, that is consistent radial thickness, axial outer diameter is uniform. Determine inherited conditions except for plastics plastic itself, mainly temperature and shear strain rate and duration of action and other factors. Extrusion temperature is too high, not only cause the extrusion pressure fluctuations, and lead to the decomposition of the plastic, the device might even lead to accidents. The groove depth is reduced, increasing the screw length, although in favor of plastic heat exchange and extend heating time, meet the requirements of plastics uniform, but will affect the amount of extrusion, and create difficulties for the screw manufacture and assembly. So make sure plastics should be an important factor in improving the rate of rotation of the screw on the plastic shear strain generated in order to achieve mechanical mixing, extrusion heat exchange balance, and thus provide protection even plastics. The size of the strain rate is determined by the shear strain forces between the screw and barrel, shear strain rate value is: where: Δ-- of shear strain rate (1 / min) D - for the screw diameter ( cm) N - the screw speed (r / min) - the groove depth (cm) shows that out of the amount of the guarantee request, you can increase the groove depth at increasing spin speed. In addition, the gap screw and barrel also affect the quality of the extrusion, the plastic of the back gap is too large, the leakage current increases, not only out of pressure fluctuations caused by the impact extrusion capacity; and due to the increase of these backflow plastic Left-over http://www.hcwks.com/ 15262655810