Patent ID: 8676358

Claim:
A method for numerical control which has a position control mode for C-axis control in which a position control is performed with a spindle as a profile control axis, and a position control mode for spindle synchronized control in which both of a reference spindle and a synchronized spindle are controlled in synchronization, the position control modes controlling the spindles using different position control gains, wherein: when the reference spindle and the synchronized spindle are controlled in spindle synchronization and a C-axis control switching command to treat the reference spindle as the profile control axis is issued during a rotation at a command speed given to the reference spindle, the reference spindle is switched to the profile control axis with both of the spindles keeping the position control mode selected during the spindle synchronized control, and when the reference spindle and the synchronized spindle are controlled in spindle synchronization, and a C-axis control switching command, which treats the reference spindle as the profile control axis, is issued during rotation of the reference spindle, both of the spindles are decelerated and stopped, with both of the spindles keeping the position control mode selected during the spindle synchronized control, and the position control modes of both of the spindles are simultaneously switched from the position control mode for spindle synchronization to the position control mode for C-axis control after both of the spindles are stopped.