Processing data during polygon processing is stored in the processing data storage unit 17. The position detection unit 18 detects a cut-start position A and a cut-end position B of a workpiece based on a change in the processing data. The position detection unit 18 detects a processing surface based on the cut-start position A and the cut-end position B.

Processing data during polygon processing is stored in the processing data storage unit 17. The position detection unit 18 detects a cut-start position A and a cut-end position B of a workpiece based on a change in the processing data. The position detection unit 18 detects a processing surface based on the cut-start position A and the cut-end position B.

The invention relates to a method for monitoring a machining tool that is used for machining primarily metal materials, comprising a cutting tool, wherein the cutting force, feed force, and passive force can be adjusted during machining, and comprising sensors to measure forces. In order that machining can be stopped 2 to 60 seconds, preferably 2 to 10 seconds, prior to failure of the cutting body, the invention proposes that the sensors continuously sense at least one of said forces during machining and machining is stopped if a sudden reduction in the sensed force occurs.