Abstract: -- A method for producing a machine component from a workpiece includes registering a dimension of a surface of the workpiece to be machined and a margin of tolerance of the dimension, generating a signature pattern for the surface to be machined, shaping the workpiece at least on the surface to be machined, where a signature pattern is simultaneously produced during the shaping, and producing a check code on the workpiece, where the signature pattern has maximum dimensions that are within the tolerance margin.

Abstract: An operating device and a method for operating a machine in automation engineering are disclosed. A touch-sensitive screen detects simultaneous contact with the screen at different positions on the screen, and an external key with a geometric key pattern is provided. A reference pattern is stored in the operating device which compares the geometric pattern determined from the different screen positions detected upon contact of the external key with the screen with the stored reference pattern and allows specific operating actions for operating the machine if the determined geometric pattern matches the stored reference pattern. Authorization to operate a machine can thus be easily ascertained.