Measure of cutting stiffness coefficient in high-speed precision turning of hardened steel

Measuring the cutting stiffness coefficient is one of the important keys to carrying out the stability limit prediction in hard cutting process. The high-speed precision turning system of hardened steel was established in numerical control lathe of CAK6150DI which used the method that applied the forced vibration to knife rest in feeding direction and two kinds of hardened bearing steel as cutting materials whose rigidity are different. First, the stiffness coefficient k(f) changed along with the feeding and the phase difference Phi between the signal of tool vibration and the cutting force were measured, then the cutting stiffness coefficient of cutting materials which are hardened bearing steel with hardness of HRC62-64 and HRC50-52 were obtained. The research could provide technical support for stability limit prediction and reference for the measure of lathe system in hard cutting process.