Process damping in metal cutting is caused by the contact between the flank face of the cutting tool and the wavy surface finish. which is known to damp chatter vibrations. An analytical model with process damping has already been developed and verified in earlier research. in which the damping coefficient is considered to be proportional to the ratio of vibration and cutting velocities. https://www.bekindtopets.com/mega-save-Harrows-Black-Knight-Soft-Tip-Darts-20gm-special-save/