Method for the orientation of a spindle and numerical control device of a machine tool embodied for the method for the orientation of the spindle

A method for the orientation of a spindle of a numerically controlled and rapidly rotating spindle by which said spindle is brought from an initial rotational speed into a predetermined position of rest, the method comprising:

• performing a first phase of orientation of said spindle by braking said spindle at a first braking rate function to a threshold rotational speed, wherein during said braking a switching over from a speed controller to a position controller is prepared, said switching over is performed at a switching time during a transition from said first phase of orientation to a second phase of orientation, said switching over is continuous in regard to position and/or rotational speed, and wherein a rotational speed of said spindle drops strictly monotonically during said switching over;
• and performing said second phase of orientation of said spindle so that a predetermined position of rest for said spindle is controlled by said position controller from said switching time until said predetermined position of rest of said spindle has been reached in said second phase at a position time, said second phase of orientation having a second braking rate function different than said first braking rate function;
• wherein a second threshold rotational speed above said threshold rotational speed is selected in such a way that a time period passes between reaching said second threshold rotational speed and reaching said threshold rotational speed, which permits said preparation of said switching over to said position controller, continuous in regard to said position or said rotational speed, from rotational speed regulation to position regulation;
• and
• wherein said method is only applied when said initial rotational speed lies above said second threshold rotational speed.