Each type of product in the plastic extrusion production line has its own operating characteristics. Only by having a detailed understanding of its operating characteristics can the machine's performance be fully utilized. Plastic hose extruder is one type of machine. Grasp the key points of operating the extruder and use the extruder correctly and reasonably. The use of a screw extruder includes a series of links such as installation, adjustment, commissioning, operation, maintenance and repair of the machine. Its use has the common features of general machines, mainly in the drive motor and reduction gearbox. However, the working system of the screw extruder, the extrusion system, has unique characteristics. Special attention should be paid to its characteristics when using the screw extruder. The installation, adjustment and commissioning of the machine are generally clearly stipulated in the extruder's instruction manual. Here is a brief summary of the operating points, maintenance and upkeep of the extruder: The operator must be familiar with the structure of the extruder he or she is operating. Characteristics, especially the structural characteristics of the screw, heating and cooling control instrument characteristics, machine head characteristics and assembly conditions, etc. must be correctly grasped in order to correctly grasp the extrusion process conditions and operate the machine correctly.
The working principle of a plastic extruder is to convert solid plastic into a uniform melt through pressure and shearing, and send the melt to the next process. The production of melt involves the process of mixing additives such as color masterbatch, blending resin, and repulverizing. The finished melt must be uniform in concentration and temperature. The pressure must be strong enough to squeeze out the sticky polymer.
All the above processes are completed through a barrel with a screw and spiral path. The plastic pellets enter the barrel through the hopper at one end of the barrel, and are then transported to the other end of the barrel through the screw. In order to have sufficient pressure, the depth of the threads on the screw decreases as the distance from the hopper increases. External heating and internal heat due to friction between the plastic and the screw cause the plastic to soften and melt. Different polymers and different applications often have different design requirements. Many options involve discharge openings, multiple feed openings, special mixing devices along the screw, cooling and heating of the melt with or without external heat sources (insulation), relative changes in the size of the gap between the screw and barrel, and the screw number, etc. For example, twin screws can mix the melt more thoroughly than single screws. Tandem extrusion uses the entire extruded melt as raw material to feed a second extruder, usually used to produce extruded polyethylene foam.
