METHOD AND DEVICE FOR IN-PROCESS TOOL BREAKAGE DETECTION

摘要

In a method and a device for detecting breakages in tools which process workpieces with good electrical conductivity, such as metals, in a cutting fashion, there is provision for at least one measured electrical variable (14) which can be recorded and is dependent on the contact state between the tool (1) and the workpiece (2), as well as the electrical resistance, the electrical conductivity, the electrical inductance and the electrical capacitance or the electrical impedance at the beginning, during and at the end of a processing cycle or processing period (19) to be measured and for the signal profiles (17) of this measured electrical variable (14) to be compared over time (18), during identical processing cycles or processing periods (19) within a workpiece or from workpiece to workpiece, at the beginning (20), during (21) and at the end (22) of the processing cycle or processing period (19), with definable threshold values (23) in a measurement and monitoring system (13) in order to detect the satisfactory state of a tool which is not broken, when the signal profiles are largely invariable, and to conclude that a tool is broken, broken off or missing if there are deviations from the normal signal profile (24) outside the definable threshold value limits (23) or when the threshold value limits (25) are infringed by the signal profile (17), and, via an electrical machine interface (15), to cause the machine controller (16) of the machine tool (5) to interrupt or stop the processing operation.