In modern society, there is a huge demand for plastic products. The production of plastic products is obtained through extrusion molding of extruders, which is a low-cost and high-efficiency method for obtaining rubber and plastic products. Therefore, it has been widely used. The working principle of sheet extruder machine is to convert solid plastic into uniform melt by pressure and shear, and then send it to the next process. The production of melt involves additives such as color masterbatch, resin blending, and re-pulverization. The concentration and temperature of the finished melt should be consistent. The pressure should be sufficient to extrude a viscous polymer.
Sheet extruder machine completes all the above processes through a barrel with a screw and a spiral channel. The pellets enter the barrel from the hopper at one end of the barrel and are conveyed to the other end of the barrel by the screw. For sufficient pressure, the depth of the thread decreases with the distance from the hopper. The external and internal heat produced by the friction between the plastic and the screw softens and melts the plastic. Different polymers and different applications usually have different design requirements for plastic extruders. Many options involve special mixing devices along the screw, cooling and heating of the melt, or relative changes in the clearance between the screw and the barrel, the number of screws, etc. For example, a twin-screw plastic extruder can mix the melt more fully than a single-screw plastic extruder. Series extrusion is a process in which the melt extruded by a plastic extruder is used as the raw material for sheet extruder machines, usually used for the production of extruded polyethylene foam.
The characteristic size of sheet extruder machine is the diameter of the screw and the ratio of the length to the diameter of the screw. Plastic extruders usually consist of at least three parts. The part near the hopper is the feeding part. Its function is to make the material enter the plastic extruder at a relatively stable speed. Generally, to avoid blocking the feeding channel, this part will maintain a relatively low temperature. The second part is the compression section, where the melt is formed and the pressure increases. The transition from the feeding section to the compression section can be sudden or gradually metered. The part near the outlet of the plastic extruder is mainly used to make the material flowing out of the machine uniform. In this part, in order to ensure the uniformity of composition and temperature, the material should have enough retention time. Another important part is the driving mechanism of the sheet extruder machine, which controls the speed of the screw and determines the output of the plastic extruder. The required power is determined by the viscosity of the polymer. The viscosity of the polymer depends on temperature and flow rate, and decreases with the increase of temperature and shear force.