摘要 |
Reference phase variation values Ãk1 to ÃKn, each of which is a variation among a plurality of phases that occur during non-machining and phase variation values Ã1 to Ãn, each of which is a variation among a plurality of phases that occur during machining are detected from measured vibration with the use of a chattering detector that is used to calculate phases of a desired number (n) of frequencies. If ÃKi - Ãi is smaller than a determination value TK, it is determined that chattering having a frequency i is occurring. |