Rapeseed, also known as brassica, is a herbaceous cruciferous crop and one of the main oil crops and nectar crops in China. Its seeds are one of the main raw materials for making oil and fat. Cultivated throughout China, it is divided into two types: winter rapeseed and spring rapeseed. Its planting area accounts for more than 40% of China's total oil crop area, and its output accounts for more than 30% of China's total oil crop production, ranking first in the world.

1. Cleaning and drying of rapeseed: If the soil, stems and leaves and other debris contained in the rapeseed are not removed before entering the oil press, it will not only affect the quality of the oil and cake, but also cause adsorption - Part of the grease reduces the oil yield. If there are sand, metal, hemp ropes and other debris in the rapeseed, it will cause wear and tear of machine parts, induce production accidents, and affect the process effect. Therefore, in order to ensure the smooth progress of production, impurities must be removed as much as possible. For some rapeseed fruits with high water content, it is also necessary to dry them in order to facilitate shelling.

2. Heat treatment: Heat treatment is one of the most important processes in the process of extracting oil, including the moistening and heating of the green body. In production, it is called steamed green body or stir-fried green body. The steamed and fried green body is called Ripe blank. If the raw material is pressed after heat treatment, it is called hot pressing, and if it is pressed without heat treatment, it is called cold pressing. Rapeseed is mainly hot pressed. The effect of heat treatment has a direct impact on the smooth progress of the entire oil production process, the level of oil yield, and the quality of oil and cake.

3. Pressing: The round pressing bar of the oil press has a zigzag curve and a tapered surface. When the rapeseed is pressed, it is pushed and squeezed by the pressing snail to create space between the pressing snail and the inner wall of the pressing cage. The volume of the press cage is constantly changing. Due to the arrangement of round press bars at the rear of the press cage, the inner wall of the press cage is in a zigzag shape. The billet is alternately pressed and relaxed here. The structure of the billet is constantly adjusted and evenly turned, so that The oil that has not been squeezed out or the billet with less squeezed oil has more opportunities to be fully squeezed.