The plastic extruder is a type of equipment used to produce a variety of items, including plastic sheets, tubes, trims, seals, and rods. Extruders can produce large or small lengths of plastic sections by using a selected type of plastic resin. In a plastic extruder, the plastic raw material in a hopper travel via gravity to the feed throat and drops onto the rotating screw, the rotation of the screw conveys the plastic forward through the heated barrel. As the plastic is conveyed forward along the screw, the channel depth decreases, forcing the plastic into a smaller area. The combination of compression and screw rotation causes friction which generates sheer heat. This heating along with the heat from the barrel heating system melts the plastic. By the time the plastic is conveyed to the end of the screw, it should be well mixed and at a proper temperature and pressure needed by the dye. The plastic is called a melt at this stage. Beyond the screw is a screen pack which consists of a wire mesh filter that the plastic must go through. A breaker plate supports the screen. The screen pack filters contaminant from the melt. There are three types of plastic extruders being manufactured currently: single-screw extruder, double-screw extruder, and ran extruder.