Device and method for determining a contact between a tool and a workpiece

A method for determining a contact between a tool and a workpiece in a machine tool, the tool and the workpiece being displaceable relative to each other, the tool or the workpiece being rotationally fixedly connected to a shaft, comprising:

• scanning a measuring scale by at least one position encoder, the measuring scale being rotationally fixedly disposed on the shaft and the position encoder being disposed in a stationary manner with respect to the shaft;
• generating position values, from the scanning of the measuring scale, that indicate a position of the shaft;
• feeding the position values to a processing device;
• determining, by the processing device, a contact between the tool and the workpiece by evaluating a progression of the position values;
• and
• signaling a result of the evaluation by a status of a displacement signal.

A machine tool, comprising:

• a device adapted to determining a contact between a tool and a workpiece in the machine tool, the tool and the workpiece being displaceable relative to each other and the tool or the workpiece being rotationally fixedly connected to a shaft, the device including:
• a processing device;
• and
• a measuring device including a measuring scale rotationally fixedly disposed on the shaft and at least one position encoder disposed in a stationary manner with respect to the shaft, the position encoder adapted to scan the measuring scale and to generate position values from the scan of the measuring scale that indicate a position of the shaft, the measuring device adapted to feed the position values to the processing device;
• wherein the processing device is adapted to determine a contact between the tool and the workpiece by evaluating a progression of the position values and to signal a result of the evaluation by a status of a displacement signal.