Machine tool comprising a device for collision monitoring

A numerically controlled machine tool comprising:

• a milling head supporting a work spindle,
• at least one feed axis, and
• a monitoring device configured to perform collision monitoring on said machine tool;
• wherein the monitoring device comprises:
• a collision sensor mounted on the milling head of the machine tool, the collision sensor comprising a vibration sensor configured to detect a vibration of the milling head supporting the work spindle,
• a collision detector configured to detect a collision of machine parts of the machine tool when a measuring value detected by the collision sensor exceeds a collision limit value, and
• signal output interface adapted to output a stop signal for stopping the at least one work spindle and the at least one feed axis of the machine tool when the collision detector detects a collision;
• and
• a determination unit configured to
• automatically set the collision limit value on the machine tool for a second machining period on a basis of a maximum measuring value detected by the collision sensor during a first machining period,
• wherein the first machining period is a reference cycle of reference machining a first workpiece based at least one portion of an NC (numerical control) program, and the second machining period is a machining cycle, being performed subsequent to the first machining period, of machining a second workspiece based on the same at least one portion of the same NC (numerical control) program underlying the reference machining of the first machining period.