FLAKING operation is cutting the kernel into thin flakes after shelling. Because the oil of the oil seeds is within small cells, weakening and breaking of these cells is important in oil extraction. By flaking the area of leaking out of oil is increased and the resistance of the cell against oil extraction is minimized. The distance, which the oil travels after leaving the cell, is shortened and bursting of cells during pressing becomes simpler. During flaking the pieces must have broad surfaces as much as possible. This can be attained by 8-10% humidity at sunflower. As the flake thickness increases, the amount of oil remaining in the extraction cake is increased. Oil amount in the cake can be adjusted by obtaining the required oil thickness, by adjusting the distance between the balls of the rollers used for flaking.