Users of 560 and 850 pellet machine often get cracked, friable, powdery pellets. Troubleshoot from ring die, raw material moisture and die surface conditions:
Check the pellet machine’s ring die. Improper compression ratio causes defects: low ratio leads to loose pellets with longitudinal cracks; excessive ratio creates overheating and brittle broken pellets. Fit a ring die with compression ratio matching wood chips, feed and other materials.
Control raw material moisture. Too dry causes tiny cracks; over-wet pellets crack from post-extrusion shrinkage. Adjust moisture via humidifying, drying or conditioning.
Inspect the ring die’s inner wall and bores. Sand and metal debris scratch the die, creating burrs that tear pellets during pressing. Minor scratches can be polished; dies with deep grooves require full replacement. Fit magnetic separators and vibrating screens upstream of the pellet machine to remove impurities and stop repeated pellet cracking issues.