PE pelletizing granulating lines are essential in the recycling industry for converting waste materials into reusable products. In particular, they play a crucial role in processing high-density polyethylene (HDPE) film. This article compares two prevalent technologies in the industry: underwater pelletizing and strand granulating lines. By understanding the core differences and benefits, you can make an informed decision based on your specific recycling needs.
PE pelletizing granulating lines are used to transform waste plastic materials into uniform pellets. These pellets can then be used for various applications, from manufacturing new products to energy recovery. For HDPE film recycling, these lines provide efficient and cost-effective solutions, contributing to sustainable practices and reducing waste.

Underwater pelletizing involves cutting strands of melted plastic into pellets as they solidify in water. The key components include:
Below are the technical specifications for the Encycle Underwater Pelletizing Line:
| Component | Specification |
|---|---|
| Extruder | Max. Output: 300 kg/h |
| Barrel Size | 65-90 mm |
| Screw Diameter | 65-80 mm |
| Melt Pump | Adjustable Speed: 100-200 rpm |
| Cutting Mechanism | Metrology Grade |
| Water Bath Quality | Temperature Control: 0.5C |
| Pellet Size Range | 1-3 mm (adjustable) |
| Water Cooling System | Recirculating Pump |
| Pellet Length Control | Precision Metering Device |
| Pellet Output Rate | Adjustable Output: 50-300 kg/h |
In strand granulating, the melted plastic is cooled and solidified before being cut into pellets. Key components include:
Below are the technical specifications for the Encycle Strand Granulating Line:
| Component | Specification |
|---|---|
| Extruder | Max. Output: 300 kg/h |
| Barrel Size | 65-90 mm |
| Screw Diameter | 65-80 mm |
| Melt Pump | Adjustable Speed: 100-200 rpm |
| Cooling Rollers | Precision Cooling: 0.5C |
| Cutting Mechanism | Mesh or Rotary Knife |
| Roll Diameter | 400 mm |
| Roll Speed | Adjustable Speed: 10-50 rpm |
| Pellet Size Range | 1-3 mm (adjustable) |
| Pellet Output Rate | Adjustable Output: 50-300 kg/h |
| Backup Cutting Mechanism | Rotational Knife |
| Feature | Underwater Pelletizing Line | Strand Granulating Line |
|---|---|---|
| Melt Cooling Mechanism | Water Bath | Cooling Rollers |
| Pellet Conditioning | Rapid Cooling | Slow Cooling |
| Pellet Size Consistency | Uniform | Variable |
| Quality Consistency | High | Moderate |
| Precision | High | Moderate |
| Maintenance Complexity | High | Moderate |
| Energy Consumption | High | Low |
| Pellet Output Consistency | High | Low |
Strand: Lower upfront cost due to simpler design and fewer precision parts.
Operational Costs:
Energy Usage:
Maintenance:
Strand: Suitable for moderate throughput requirements. Lower pellet output but still effective for medium-scale operations.
Drying Requirements:
Strand: Additional drying step required to remove moisture from pellets.
Pellet Quality:
Strand: Suitable for moderately consistent raw materials but with less uniform pellet quality.
Customization Options:
When comparing underwater and strand granulating lines, several factors come into play. Underwater pelletizing offers precision cutting and higher quality pellets, making it ideal for high-throughput and consistent material handling. However, it comes with higher initial and operational costs. On the other hand, strand granulating lines are more affordable, simpler to maintain, and cost-effective in terms of energy consumption. However, they produce less consistent pellets and require additional drying.
Ultimately, the choice between underwater and strand granulating lines depends on your specific requirements. If you need high-quality and uniform pellets for consistent output, the underwater line is the better choice. For lower upfront costs and moderate throughput, the strand granulating line is more suitable. Encycle Machine's offerings provide reliable solutions for both technologies, ensuring high-quality pellet production and operational efficiency.