The cutting part of the turning tool is composed of the main cutting edge, the secondary cutting edge, the rake face, the flank face and the secondary flank face. Its geometry is determined by the rake angle γo, the rear angle αo, the entering angle κr, the inclination angle γS, the secondary declination angle κr' and the radius of the arc of the cutting edge rε. The selection of turning tool geometry parameters is affected by a variety of factors and must be selected according to the specific situation. The rake angle γo is selected according to the composition and strength of the workpiece material, and a smaller value should be taken when cutting the material with higher strength. For example, the rake angle of the tungsten carbide turning tool is 10°~15° when cutting ordinary carbon steel, and -2°~-10° when cutting chromium-manganese steel or quenched steel. Under normal circumstances, the rear angle is taken 6°~10°. The entering angle κr is determined according to the rigidity conditions of the process system, generally 30 ° ~ 75 °, the stiffness is poor, and the greater value is taken when the rigidity is poor, and when the stepped shaft is turned, it is greater than or equal to 90 ° due to the needs of the cutting mode.
