Strand Pelletizing Without Water Bath Cooling
The air cooling strands pelletizing line is designed for materials that are not suitable for standard water cooling strand pelletizing. Some formulations may become brittle, break easily, absorb moisture, or show unstable strand behavior when they pass through a water bath. For these materials, air cooling provides a more suitable and controlled cooling method.
Instead of using a water bath, the extruded strands are cooled by air while moving along a cooling conveyor. This helps avoid direct water contact and reduces processing issues for selected high-filler, biodegradable, flame-retardant, or water-sensitive formulations.
The system keeps the process simple while offering better compatibility for materials that cannot be pelletized reliably through conventional water cooling.
How the System Works
After the compound exits the extruder through the strand die, the molten strands are guided onto an air cooling conveyor. The strands are cooled gradually by air as they move forward.
Once the strands reach the proper temperature and strength, they are fed into the strand pelletizer. The pelletizer cuts the strands into uniform cylindrical pellets. The pellets are then screened by a vibrating classifier to remove fines and irregular particles before final collection.
Because no water bath is used, the process is especially useful for materials where moisture contact or sudden water cooling may affect strand stability.
Main Components
The air cooling strands pelletizing line typically includes:
- Strand die
- Air cooling belt conveyor
- Strand guiding system
- Strand pelletizer
- Vibrating classifier
- Product collection system
Suitable Materials and Applications
This system is commonly used for:
- High-filler masterbatches: PP / PE + CaCO3
- 100% biodegradable masterbatch: PLA / PBAT + starch, CaCO3, talc, etc.
- Flame-retardant masterbatch: PP / PA / ABS / EVA / PBT + flame retardant additives
- Water-sensitive formulations
- Brittle formulations that are not suitable for water cooling strand pelletizing
- Selected compounds requiring gradual air cooling before cutting
Key Advantages
- Avoids direct water bath cooling
- Suitable for water-sensitive or brittle materials
- Simple system structure
- Easy operation and maintenance
- Stable strand cooling for selected formulations
- Practical for high-filler and biodegradable compounds
- Lower process complexity compared with some specialized pelletizing systems
Practical Solution for Sensitive Formulations
When a formulation does not perform well in water cooling, air cooling strand pelletizing provides a more suitable path from extrusion to cutting. The cooling conveyor length, strand guiding design, pelletizer capacity, and classification system can be selected based on the material’s brittleness, moisture sensitivity, filler content, and production target.
