No matter what kind of machining, the shears have three main angles: rake angle, cut-in angle and rear angle. Its function is as follows: 1 rake angle: affect the cutting force, cutting edge strength and chip flow characteristics; 2 cut-in angle: control the direction of cutting force, effectively reduce the chip, protect the weakest part of the cutting edge; 3 rear angle: ensure while tool cutting, it does not rub with the workpiece.

Through comprehensive optimization of the three angles of the tool, the cutting edge can be strengthened, and the workpiece material can freely flow out from the cutting area, thereby reducing the cutting force and increasing the tool life.