The function of the rubber extruder machine is to use heating, pressure and shearing methods to transform solid plastic into a uniform melt and send the melt to the next process. The production of the melt involves the process of mixing additives such as color masterbatches, blending resins, and pulverizing. The finished melt must be uniform in concentration and temperature. The pressure must be large enough to squeeze out the viscous polymer.
The rubber extruder completes all the above processes through a barrel with a screw and spiral channel. The plastic pellets enter the barrel through a hopper, and then are conveyed to the other end of the barrel through the screw. In order to have sufficient pressure, the depth of the thread on the screw decreases as the interval to the hopper increases. External heating and internal heat generated by friction between the plastic and the screw cause the plastic to soften and melt. Different polymers and different applications often have different design requirements for extruders. Many options involve discharge ports, multiple feeding ports, special mixing devices along the screw, cooling and heating of the melt, or no external heat source (exhaust heat extruder), the gap between the screw and the barrel changes relatively Size, and the number of screws, etc. For example, a twin-screw extruder can mix the melt more fully than a single-screw extruder. Tandem extrusion is the use of a rubber extruder to extrude the melt, as a raw material to supply the second rubber extruder, usually used to produce extruded polyethylene foam.