In the modern manufacturing landscape, plastic pelletizing plays a vital role in the recycling and production of plastic materials. This article will explore the plastic pelletizing process with a focus on the 1000kg/hr LDPE HDPE Film Recycling Granulation Pelletizing Line.
Plastic pelletizing is the process of converting plastic raw materials or waste plastics into small, uniform pellets. These pellets serve as the fundamental units for subsequent plastic processing operations such as injection molding, extrusion, and blow molding. The importance of this process lies in its ability to ensure the quality and consistency of the plastic feedstock, thereby facilitating efficient and high-quality plastic product manufacturing.
The LDPE HDPE LLDPE Film Recycling Pelletizing Line is engineered to handle various waste plastics like post-consumer LDPE film, PP woven bag, PP non-woven fabric, PS EPS foam, etc. It incorporates the latest 3 in 1 compacting - extruding - cutting technology. This innovative design enables the immediate cutting, heating, and agglomeration of the film. The single or double stage pelletizing system equipped with a vacuum degassing vent is capable of melting the material effectively and discharging moisture or gas. The self-cleaning automatic filter screen is a significant feature that helps save labor costs, and the two-stage filtration ensures the production of high-quality granules. The die face cutting system offers horizontal or vertical water ring cutting options, ultimately yielding clean, dry, and strong pellets suitable for applications like film blowing and injection molding.
This pelletizing line is applicable to a wide variety of materials. It can process PE agriculture film, LLDPE stretch film, PP Woven Bag, Washed PP Jumbo Bag Scrap, PP Non Woven Fabric, and other soft plastics such as PE OPP CPP BOPP film, PS foam, and PP Raffia. The material can be in different shapes including film, bag, and regrind, and can come in forms like rolls, loose, or bundled.
The pelletizing line comes in multiple models with different screw diameters and length-to-diameter (L/D) ratios. For example, the RCDJ85 model has a screw diameter of 85mm and an L/D ratio of 33, with a PE processing capacity of 180 - 220 kg/h and a PP processing capacity of 160 - 200 kg/h. As the screw diameter increases, the processing capacity also increases. The RCDJ180 model has a screw diameter of 180mm and an L/D ratio of 28, capable of processing 800 - 1000 kg/h of PE and 650 - 800 kg/h of PP.
The process begins with the use of a belt conveyor equipped with a metal detector. The metal detector plays a crucial role in removing any metal contaminants from the plastic waste. Once the metal is removed, the plastic waste is sent to the compactor. The shredder in the compactor pre-cuts the waste, and the automatic feeding system along with the compactor cutter enhances the feeding performance, ensuring a smooth and continuous material flow into the subsequent processing stages.
The pre-compacted materials are then fed into the mother extruder. The mother extruder features a specially designed screw structure that is optimized for melting the materials. It exhibits better melting performance and higher output compared to traditional extruders. The screw rotates within the heated barrel, creating friction and heat that gradually softens and melts the plastic. The temperature profile along the barrel is carefully controlled to ensure that the plastic reaches the ideal melting state. Subsequently, the material passes through the baby extruder, which further refines the melting process. The hydraulic screen changers in both extruders are equipped with pressure sensors. These sensors alert the operator when it is time to change the nets, ensuring the continuous and efficient operation of the extrusion process while maintaining the quality of the melted material.
After the melting and extrusion steps, the material reaches the die face cutting system. Here, the operator can choose between die face cutting or strand noodle cutting methods based on the specific requirements. The cutting speed is precisely controlled by an inverter, allowing for the production of pellets with consistent sizes. In die face cutting, the molten plastic is forced through a die with small holes, and the extruded strands are immediately cut into pellets by the rotating blades. In strand noodle cutting, the extruded strands are first cooled slightly and then cut into pellets. Once the pellets are formed, they enter the water cooling tank made of stainless steel in an L shape. The cooling tank rapidly cools the pellets, solidifying their shape.
The cooled pellets are then sent to the dewatering machine, which combines a vibration dryer and a horizontal type centrifugal dryer. This dual drying mechanism ensures that the final granules have a moisture content below 1%, meeting the quality standards for further processing. After drying, the pellets pass through a vibrator screen made of SUS 304 with double layers of 10mm and 2mm for final screening and selection. The selected pellets are then stored in a packing silo made of stainless steel SUS304, which is equipped with hooks for big bags, facilitating easy storage and transportation.
The pelletizing line is designed to produce granules with a high level of quality. The final moisture content is strictly controlled below 1%, and the granules are uniform in size and appearance. This ensures that the pellets can be used in various plastic processing applications without causing issues related to quality or performance.
The equipment utilizes world-famous brand parts to ensure reliable performance and durability. Components such as Siemens motor, Fuji Inverter, SKF bearing, Mesutronic metal detector, and 38CrMoA1A bimetal screw are incorporated. These high-quality components work together to enhance the overall efficiency and stability of the pelletizing process, reducing the frequency of maintenance and ensuring long-term operation.
In conclusion, the plastic pelletizing process, especially as exemplified by the 1000kg/hr LDPE HDPE Film Recycling Granulation Pelletizing Line, is a complex yet highly efficient operation that combines advanced technology and quality components to recycle waste plastics and produce high-quality plastic pellets for a wide range of industrial applications.
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