Numerical control method

A numerical control method in an apparatus having a C axis, a feed axis, and having a C-axis control function for numerically controlling a spindle in the direction of rotation, comprising the steps of:

• defining a first G-code word for achieving agreement between axis control characteristic values including an acceleration/deceleration time constant and a servo-loop gain of a C-axis motor control system, and axis control characteristic values including an acceleration/deceleration time constant and a servo-loop gain of a feed-axis motor control system;
• defining a second G-code word for restoring the axis control characteristic values changed by the first G-code word to original axis control characteristic values;
• commanding the first G-code word before simultaneously controlling the C axis and the feed axis in order to make the axis control characteristic values agree;
• simultaneously controlling the C axis and the feed axis;
• commanding the second G-code word after simultaneous controlling of the C axis and the feed axis ends in order to restore the axis control characteristic values changed by the first G-code word to the original axis control characteristic values;
• and
• controlling at least one of the C axis and the feed axis using the original axis control characteristic values.