Pellet mills working principle is, mash feed is forced outward through holes in a ring die by the action of two or three rollers, which is then cut to a predetermined size. Before mechanical process, steam can be injected into the conditioner at temperature 85 degrees celsius. The result of conditioning and pelleting process, starch is gelatanized, salmonella risk also is eliminated. Pelleting technology also used in pelleting wheat bran, bagasse, wood, plastics, papers, sewage sludge, chicken manure, classified MSW and chemicals. Die hole sizes usually range from 1.6 mm. up to 22 mm.

Pellet mills are consist of these sections:

- Feeder
- Conditioner
- Pellet mill