1. When the screw type oil expeller is running, the processed oil enters the chamber from the hopper, and the screw turns to push the embryo inward continuously. Because the embryo is in motion in the chamber of the oil press, under the condition of high pressure in the chamber, there is a great friction resistance between the embryo and the screw, the embryo and the chamber, so that the micro-material of the embryo can be produced. Friction causes relative motion.