After more than 100 years of development, plastic extruders have been derived from the original single-screw, twin-screw, multi-screw, and even no-screw models. Plastic extruder can be used with various plastic forming auxiliary machines such as pipe, film, monofilament, flat wire, packing belt, extruding mesh, plate (sheet) material, profiled material, granulation, cable coating and so on. Match to form various plastic extrusion molding production lines to produce various plastic products. Therefore, plastic extruder is one of the widely used models in the plastic processing industry, now or in the future.
Working Principle
The function of the extruder is to use heat, pressure and shear to transform the solid plastic into a uniform melt and send the melt to the next process. The finished melt must be homogeneous in concentration and temperature. The pressure must be large enough to extrude the viscous polymer. The extruder completes all the above processes through a barrel with a screw and a screw channel. Plastic pellets enter the barrel through a hopper at one end of the barrel, and are then conveyed to the other end of the barrel by a screw. In order to have sufficient pressure, the depth of the threads on the screw decreases with increasing distance from the hopper. External heating and internal heat from the plastic and screw due to friction soften and melt the plastic.
Application
Plastic extruders can process different types of waste plastics into plastic pellets. Now the price of plastic pellets is increasing, and the investment is small and the return is large. Mainly used for processing waste plastic films (industrial packaging films, agricultural plastic films, greenhouse films, beer bags, handbags, etc.), woven bags, agricultural convenience bags, basins, barrels, beverage bottles, furniture, daily necessities and most of the common waste Plastic is the most widely used and most popular plastic recycling processing machinery in the waste plastic recycling industry.
Classification
1. According to the number of screws, it is divided into single-screw extruder, twin-screw extruder and multi-screw extruder;
2. According to whether there is a screw in the extruder, it is divided into screw extruder and plunger extruder;
3. According to the operating speed of the screw, it is divided into ordinary extruder, high-speed extruder and ultra-high-speed extruder;
Ordinary extruder: the rotating speed is below 100r/min.
High-speed extruder: the rotating speed is 100~300r/min.
Ultra-high-speed extruder: the rotating speed is 300 ~ l500r/min.
4. According to the assembly structure of the extruder, it is divided into an integral extruder and a separate extruder;
5. According to the spatial position of the screw in the extruder, it is divided into horizontal extruder and vertical extruder;
6. According to whether the extruder is vented during processing, it can be divided into vented extruder and non-vented extruder.