PURPOSE: To precisely judge the tool life, by detecting the change of cutting resistance of a tool directly as a deformation amount of the tool.
CONSTITUTION: When a tool 1 passes over a noncontact gap detecting sebsor 3a, the gap amount between the tool 1 and an arm 1a is outputted as a gap detected signal 10. The maximum output signal of the signal 10 is held at a peak hold circuit 14 of a tool distortion amount display judging apparatus 20. Similary, when the tool 1 passes over a noncontact gap detecting sensor 3b, the maximum output signal of a gap detected signal 11 is held at a peak hold circuit 14. The difference between the maximum output signals is inputted into a hold circuit 15, and when the tool 1 passes over a proximity switch 6b an action signal 12 is inputted into the circuit 15 whose output is inputted to a meter relay 16 to display a tool distortion amount. When this tool distortion amount has reached an allowance value or above it, it is assumed that the tool life is attained and the machine tool is temporarily stopped.
KOSUGI HITOSHI
YAEGASHI MASASHI
