The underwater pelletizer is similar to the air pelletizer and the water jet granulator. The equipment part mainly covers: plastic granulator, single and double screw plastic extruder, plastic film blowing machine, bag making machine, printing machine, coating Machine, tape machine, tape slitting machine, slitting machine, strapping machine. The modified formulation is mainly based on alloy materials, especially PET, PC, ABS, (PP, PA) materials that are currently growing in applications; Plastic formulas have developed plastic wrap, degradable films, PET tackifying and toughening formulations . The difference is that it has a smooth flow of water through the mold surface, and direct contact with the mold surface. The cutting chamber is sized just enough to allow the cutter to rotate freely over the die surface without limiting the flow temperature. The molten polymer is extruded from the die, the rotary knife cuts the pellets, and the pellets are brought out of the pelletizing chamber with tempered water and into a centrifugal dryer. In the desiccator, water is drained back to the tank, cooled and recycled; the pellets are removed by a centrifugal dryer. 
　　Strip production line is not costly, easy to operate, and easy to clean. This has advantages for colorant compounding because replacement of two batches of different colorants must thoroughly clean the equipment. However, the defect of the strip forming method is that the cooling section needs to occupy space, and its length is determined according to the temperature requirement of the polymer. 
　　Most polymers must be blended before they are made into the final product and then pelletized to become a marketable raw material. The power required by the granulator is proportional to the amount of extrusion and is exponential to the size of the screen. There are many different granulator designs, but all granulators can be divided into two major categories: cold-cut pelletizing systems and die-surface hot-cut pelletizing systems. The main difference between the two is the timing of the pelleting process. The cold pelletizing system cuts pellets from the solidified polymer at the end of the process; whereas in the hot die pelletizing system, the pellets are pelletized when the molten state polymer emerges from the die, and the pellets are processed downstream. cool down. Both pelletizing systems have their own advantages and disadvantages. 
　　Cold pelletizing system: The cold pelletizing system includes a die, a cooling zone (air-cooled or water-cooled), a drying zone (if water-cooled) and a pelletizing chamber. There are two major types of cold pelletizing systems, namely pellet pelletizers and strip pelletizers.