Automatic tool changing method and device for machine tool controlled by numerical controller
An automatic tool changing method and an automatic tool changing device for a machine tool with a numerical controller capable of reducing the occurrence of impact due to tool exchange with a simple structure. A turret that rotates about a pivot shaft is provided on an arm and holds multiple tools. A swing cam CS that cooperates with a swing roller provided on the turret is provided on a spindle head. As the spindle head descends the turret rotates due to the action of the swing roller and the cam CS and exchanges tools. In order to lessen the impact that occurs at this time, the velocity of the spindle head is controlled. The ideal swing velocity pattern for the turret is obtained, and from this swing velocity pattern the swing position of the turret at each moment is obtained. From the swing roller and cam CS positions at this position the position of the spindle head 34 is obtained. From the acquired spindle head position the spindle head velocity pattern is obtained, and the spindle head is controlled using this velocity pattern. As a result, an ideal swing pattern can be achieved, and therefore no impact arises.