How many pelletizing methods are there in a plastic pelletizer?

How many pelletizing methods are there in a plastic pelletizer? Pelletizing is a key component of the extrusion pelletizing equipment's auxiliary machinery. Pelletizing auxiliary machinery can be divided into two types, hot cutting and cooling, depending on their operating mode and function. Hot cutting can be further categorized into dry cutting, water ring cutting, and underwater cutting. Their specific operating methods and application characteristics are as follows.

① Dry cutting: Dry pelletizing involves the extrusion of strands of material into uniformly sized pellets immediately after extrusion by the extruder. Rotating blades then convey the pellets through a fan through a pipe to a cooling and screening device. This pelletizing method is suitable for mixing and pelletizing polyvinyl chloride (PE) materials.

② Water ring cutting: Water ring pelletizing involves the extrusion of strands of material into pellets immediately after extrusion by the extruder. Rotating blades then throw the pellets into a high-speed rotating water ring attached to the inner wall of the pelletizer. The water then carries the pellets to a water separator for dehydration. After drying, the pellets are then conveyed to a cooling device for cooling, resulting in the finished product. This production method is suitable for the compounding and pelletizing of polyolefin materials.

③ Underwater pelletizing: The extruded strands are immediately cooled in water before being cut into pellets. Circulating water then transports the pellets to a centrifugal dryer for dehydration and drying. This pelletizing method is particularly suitable for pelletizing raw materials compounded in twin-screw extruders and is used for large-scale production.

④ Cold pelletizing: Cold pellets are formed into flakes from the mold in front of the barrel of a plastic pelletizer after plasticizing in the extruder. These flakes are first cooled in a water trough before being reeled and pelletized using a dedicated pelletizer. This extrusion pelletizing method is suitable for compounding and pelletizing polyethylene, polypropylene, ABS, and polyethylene terephthalate.