Shaft precision parts processing parts often cut back grooves on the outer diameter, cut off the workpiece, and cut the sealing groove. Therefore, the geometry of the cutting knife and the external grooving knife must be ground and shaped. The geometrical shapes of the cutting knife and the external grooving knife are basically the same as the external 90° offset knife die method. The length of the grooving knife head is shorter, which is easier to sharpen; the cutting knife head is long, the rigidity is insufficient, and the sharpening is more difficult. Commonly used cutting knives are classified into high-speed steel cutting knives and cemented carbide cutting knives according to their materials.
The sharpening angle of the cutting knife is generally determined according to the workpiece material. When the workpiece material is soft, a larger rake angle, main relief angle, secondary relief angle, and secondary deflection angle can be used; vice versa.
The feed speed of the cutting knife generally has three states.
1. The feed of the tangent knife can be controlled by hand at any time, so that it will not pierce the knife, but it has high strength and is generally used for cutting small diameter workpieces.
2. The motor feed of the tangent knife is highly efficient, but you must pay attention to the phenomenon of cutting the knife (when the rigidity of the workpiece and the tool is not fixed, the main cutting force is increased due to the increase in the instantaneous cutting amount, which causes the tool to bend) phenomenon, when machining precision parts , The feed speed needs to be adjusted accurately.
3. Reverse cutter motor feed, low speed, accurate feed speed adjustment, generally used for cutting large diameter workpieces.