There is no need to heat outside the machine, through the screw extruding of the raw material, heat is produced and gathered during the rotary working process in the airtight environment, and during the high-temperature ripening process, the starch and fiber of the raw material become swell. Then under the pressure-tight condition, the material will be formed into pellets by shaping mold. In the end, through the high pressure produced by the regular rotating of the screw, after being cut by the forepart cutter which rotates regularly and high-speedily, the finished products will be shrunk and become small average puffed balls in room temperature and pressure.
