The primary differences between single-stage and two-stage recycling pelletizing machines lie in structural complexity, processing capacity, and material compatibility, as detailed below:
Structural and Process Differences
- Single-stage Recycling Machine
Typically equipped with a single extruder, featuring a double degassing system and one filtration unit. Its integrated cutting and pelletizing system is suitable for processing PE and PP films, multilayer films, stretch films, EPE foam, pre-washed film flakes, and some printed films (with a print coverage of up to approximately 50%). Single-stage machines are easy to operate and maintain, making them ideal for recycling industrial waste with low contamination and moderate print coverage. - Two-stage Recycling Machine
Equipped with two extruders, three degassing zones (including double degassing and an additional degassing section at the connecting zone), and two filtration units, significantly enhancing filtration and degassing capabilities. This design allows the processing of materials with high print coverage (up to 100%), making it especially suitable for heavily printed films, laminated films, and post-consumer waste. With two-stage filtration and triple degassing, these machines significantly improve the quality and stability of the final pellets.
Processing Capacity and Applicable Materials
| Feature | Single-stage Recycling Machine | Two-stage Recycling Machine |
|---|---|---|
| Number of Extruders | 1 | 2 |
| Degassing Zones | 2 (Double Degassing) | 3 (Double Degassing + Connecting Zone Degassing) |
| Filtration Units | 1 (Double Piston Filter) | 2 (Double Piston + Manual Filter) |
| Suitable Materials | PE, PP films, multilayer films, stretch films, EPE foam, pre-washed flakes, printed films with ≤50% coverage | All materials suitable for single-stage, plus films with up to 100% print coverage |
| Target Users | Film manufacturers, blown film producers, PP woven bag manufacturers, general recycling centers | Processors of heavily printed films, laminated films, and post-consumer waste |
| Pellet Quality | Good | Superior and more stable |
Additional Technical Features
- The third degassing zone in the two-stage machine effectively removes ink and excess moisture, while the second filtration unit further ensures pellet purity.
- Both machines utilize an integrated cutting-extrusion-pelletizing design, streamlining the operation process.
- The two-stage system performs better when handling highly printed or complex waste materials, though it entails higher investment and maintenance costs.
Selection Recommendations
- If the recycled material has low print coverage (≤50%) and budget constraints exist, the single-stage recycling machine offers an economical and efficient option.
- If the recycling process involves high print coverage materials (up to 100%) or complex post-consumer waste, and high pellet quality is required, the two-stage recycling machine is the more suitable choice.
In conclusion, the core distinction between single-stage and two-stage recycling pelletizing machines lies in the number of extruders and the complexity of their degassing and filtration systems, which directly influence their waste handling capabilities and final pellet quality. Users should make informed decisions based on the characteristics of their waste materials and production capacity requirements.