Working principle

1) During extruding process, material feed from the end of machine cavity convey to the whole cavity by screw, then divided into several regions at extruded part, each region have a ring (press ring) to control flow and press. Screw convey function drive the material through the gap between the press ring and cavity, screw rotating motion generate energy with the friction between material and extruder parts is transformed into thermal energy.

2) In most cases, the material rich with starch and protein is cooked into a sticky dough or gelatinous dough. During the transform process, the material have a large physical and chemical changes, mainly is the results of starch and protein changes.

3) When the material is extruded through molding holes at the end of machine cavity, make the dough material processed into a certain shape. Due to the large of propulsive force of screw inside cavity, the material have a huge pressure, when material is extruded from the molding holes, it instantly vaporized a large quantities moisture, greatly reduce the material moisture content.

4) When produce low density products, it would have a large expansion depends on the molecular structure of material, and all condition and material used during extruding process.

5) When produce high density products, it would not expansion large depends on the purging pressure port on the cavity and all condition and material used during extruding process.