Patent ID: 7878070

Claim:
A method for determining a clamping force on a chuck for clamping a workpiece and fitted to a machine spindle of a machine tool, the chuck comprising: a chuck body having: a substantially rotationally symmetrically formed basic body; a cone portion-shaped receiving opening provided on said basic body and designed for a force-transferring reception of a clamping head:, and a deformation sensor fitted to said basic body and constructed for a determination of a deformation of said basic body in a circumferential direction to said basic body; and a clamping head received in said chuck body and having several clamping jaws mutually spaced by separation slots, wherein said clamping jaws are interconnected in relatively movable manner by elastic connecting elements between them and wherein said clamping jaws are provided for fixing a workpiece in said chuck, wherein the method comprises the steps of: determining a deformation of said chuck body by means of said deformation sensor with said machine spindle being held in a stationary state and said workpiece being held fixed, determining a deformation of said chuck body during a rotary movement of said machine spindle and with said workpiece fixed, calculating a deformation difference between said stationary state and said rotary movement, and outputting or displaying said deformation difference or comparing said deformation difference with a value table and outputting a signal on dropping below a desired value for said deformation difference.