METHOD OF DERIVING NATURAL FREQUENCY OF CUTTING TOOL METHOD OF CREATING STABILITY LIMIT CURVE AND APPARATUS FOR DERIVING NATURAL FREQUENCY OF CUTTING TOOL

摘要

An apparatus which does not have an artificial deviation, does not require troublesome work or special functions, and can derive a more accurate natural frequency of the cutting tool, and the like. A machining executing section 2 for machining the workpiece by a predetermined distance or time at each rotational speed while changing the main shaft rotational speed of the machine tool 20 step by step, A cutting force detection unit 6a for detecting a cutting force acting on the tool, a frequency analysis unit 6f for obtaining a displacement and a cutting power spectrum by frequency analysis of displacement data and cutting power data obtained for each spindle rotational speed, (3), and a compliance spectrum obtained by dividing the obtained displacement spectrum by a cutting power spectrum is calculated for each main shaft rotation speed, and then an integrated compliance spectrum obtained by superimposing the respective compliance spectra is calculated. A frequency representing the maximum compliance value is derived as a natural frequency And a natural frequency derivation unit.