Machine tools - monitoring device for detecting cutting tool fractures

摘要

Vibrations generated by interaction of a cutting tool and workpiece are sensed and a high frequency vibration signal with a frequency in a range between 30KHz and 100KHz is derived. At least one parameter related to force acting on the tool during a cutting process is sensed and a low frequency signal with a frequency less than about 1 KHz is produced. Each of the signals is preprocessed, sampled and digitised. The first and second tracking means signals are computed from a given number of previous samples. A pattern recognition device detects signal transients that may be caused by a tool break. An alarm determines that transients in the first and second mean signals are inclose time coincidence and occur in a designated time window, and generates a minor tool break alarm. -