There are also many differences in the extrusion process in Dalian, but the basic process is roughly the same. It is more common to use solid state feeding to extrude products. The extrusion forming process is to add granular or powdery solid materials into the hopper of the extruder. There is a heater outside the barrel of the extruder. In the process of non-rubber extruder, the extrusion weighing extrusion is carried out by using the hydraulic press pressure on the die itself.
It refers to a processing method in which materials are continuously pushed forward by the screw and made into various cross-section products or semi-products through the head through the action between the barrel and the screw of the extruder while being heated and plasticized. The requirement of melt strength is not high. Although extrusion moulding also has geometrical limitations, it is not completely cured after the exit moulds. In this free state, sometimes it can not be formed well because of low melt strength.
The expansion of the extruded outlet is annoying. Therefore, the viscoelastic control of injection and extrusion materials will be different. The temperature of extruded material fluctuates both radially and axially due to the change of screw speed, which affects the quality of products. The strength of products varies from point to point, resulting in residual stress and glossy surface. In order to ensure the quality of products, the temperature should be stable.
The factors affecting extrusion rate are head resistance, screw and barrel structure, screw speed, heating, cooling system and plastic characteristics. But when the product has been determined, the extrusion rate is only related to the screw speed. The extrusion rate also fluctuates, affecting the geometry and size of the product. Extruded plastics often need to be cooled and shaped.
Curing of the extruded rubber, however, needs further vulcanization. Different products can be obtained by using different extrusion equipment and processes. When the strip is off the die, it is cooled by air or water and cut off with a rotary knife immediately. The latter is to cool all the strips before feeding them into the granulator.