DERIVATION METHOD FOR NATURAL FREQUENCY OF CUTTING TOOL, PREPARATION METHOD FOR STABLE LIMIT CURVE, AND DERIVATION APPARATUS FOR NATURAL FREQUENCY OF CUTTING TOOL

摘要

PROBLEM TO BE SOLVED: To provide an apparatus capable of deriving a more accurate natural frequency of a cutting tool both by having no artificial dispersion and by dispensing with a troublesome work or a special skill.SOLUTION: An apparatus of this invention comprises a processing execution part 2 for executing the action of processing a workpiece by a predetermined distance or time at each rotational speed while gradually changing the spindle rotational speed of a machine tool 20, a displacement detection part 5 for detecting a positional displacement of the tool during processing, a cutting power detection part 6a for detecting a cutting power acting on the tool, a frequency analysis part 3 for analyzing each of displacement data and cutting power data acquired for each spindle rotational speed to acquire displacement and cutting power spectrum, and a natural frequency derivation part for calculating an integrated compliance spectrum with each compliance spectrum overlapped after a compliance spectrum, which is a value of an acquired displaced spectrum divided by a cutting power spectrum, is calculated for each spindle rotational speed to derive a frequency indicating a maximum compliance value of the same as a natural frequency.SELECTED DRAWING: Figure 2