초록 ▼

Sharp tools have different cutting characteristics from dull or worn tools. Among these differences is that a wear land develops on the cutting tool so that more of the cutting tool comes into contact with the workpiece during the cutting process. The increased contact area between the tool and work

Sharp tools have different cutting characteristics from dull or worn tools. Among these differences is that a wear land develops on the cutting tool so that more of the cutting tool comes into contact with the workpiece during the cutting process. The increased contact area between the tool and workpiece forces more energy to be consumed by the cutting machine in making a cut because more energy is expended in non-productive work. Indications of an increase in non-productive work are the increased power or force necessary to operate a spindle in lathes, milling machines, etc., and the increased energy in cutting vibrations in a low frequency range emitted during the cutting process. Another indication of decreased efficiency of the cutting process is the decreased energy in cutting vibrations in a high frequency range emitted during the cutting process. A method and apparatus are described for continuously monitoring a ratio of spindle force or power or low frequency vibration energy to high frequency vibration energy during the cutting process, and generating an output warning signal when the radio reaches a preselected level correlated with excessive tool wear.

대표청구항 ▼

A method for automatically detecting worn cutting tools used in machining workpieces comprising the steps of: (a) sensing data during a machining operation and generating at least one electrical signal indicative of said data; (b) utilizing said at least one electrical signal to obtain at least two

A method for automatically detecting worn cutting tools used in machining workpieces comprising the steps of: (a) sensing data during a machining operation and generating at least one electrical signal indicative of said data; (b) utilizing said at least one electrical signal to obtain at least two component signals, a first component signal indicative of data of high frequency vibration having a frequency range of from about 25 kHz to about 100 kHz at the tool-workpiece interface and a second component signal indicative of data corresponding to energy consumed during the cutting process; (c) sampling said sampled first component signal to converting said sampled first component signal to digitized values and deriving a tracking cutting vibration signal corresponding to at least one statistical value of said first component signal that tracks changes in the vibration energy in that signal; (d) sampling said second component signal, converting said sampled second component signal to digitized values, and deriving a tracking signal corresponding to at least one statistical value of said second component signal that tracks changes in the energy in that signal; (e) using said tracking first component vibration energy signal and said tracking second component energy signal to obtain a ratio signal representative of the ratio of said tracking first and second component energy signals; and (f) producing an output indication when said ratio signal representative of said ratio reaches a predetermined threshold level indicative of a preselected amount of cutting tool wear.