Method and apparatus for monitoring the cutting condition of a machine tool during machining of a workpiece

Claim 1

Apparatus for monitoring the cutting condition of a cutting machine tool during machining of a workpiece, comprising: first means (19) for sensing acoustic emissions resulting from the machining of said workpiece by said cutting tool; second means (20-36) coupled with said first means (19) for producing a first electrical signal which varies with changes in the sensed acoustic emissions; third means (42, 50, 52, 54) responsive to said first electrical signal for producing a second electrical signal representing the energy rate of the sensed acoustic emissions; fourth means (40) responsive to said first electrical signal for producing a third electrical signal representing the RMS value of said first electrical signal; fifth means (15) for selecting one of said third and fourth electrical signals and for comparing the selected signal with a threshold value related to the cutting condition of said cutting tool; and, sixth means (25) responsive to said fifth means (15) for providing an indication when the selected signal is in preselected relationship to said threshold value.

Claim 7

A method of monitoring the cutting condition of a cutting machine tool during machining of a workpiece, comprising the steps of: (A) sensing acoustic emissions related to the cutting condition of said tool and resulting from the machining of said workpiece by said tool; (B) producing an electrical signal which varies in magnitude with changes in the acoustic emissions sensed in step (A); (C) amplifying said electrical signal; (D) storing data representing reference values; and (E) varying the amplification of said electrical signal performed in step (C) in accordance with said stored data to establish the magnitude of said electrical signal at a desired reference value; (F) converting said amplified electrical signal to an RMS signal representing the RMS value of said amplified electrical signal; (G) converting said amplified electrical signal to a first set of digital data representing the energy rate of said acoustic emissions; (H) converting said RMS value into a second set of digital data; (I) selecting one of said first and second sets of digital data to be compared with the reference data stored in step (D) in accordance with the memory stored programmed instructions; (J) comparing the set of digital data selected in step (I) with the data stored in step (D); and, (K) selectively activating an alarm based on the results of the comparison performed in step (J).

Claim 8

A method of monitoring the cutting condition of a cutting machine tool during machining of a workpiece, comprising the steps of: (A) sensing acoustic emissions related to the cutting condition of said tool and resulting from the machining of said workpiece by said tool; (B) producing an electrical signal which varies in magnitude with changes in the acoustic emissions sensed in step (A); (C) amplifying said electrical signal; (D) storing data representing reference values; and (E) varying the amplification of said electrical signal performed in step (C) in accordance with said stored data to establish the magnitude of said electrical signal at a desired reference value; (F) converting said amplified electrical signal to an RMS signal representing the RMS value of said amplified electrical signal; (G) converting said amplified electrical signal to a first set of digital data representing the energy rate of said acoustic emissions; (H) converting said RMS value into a second set of digital data; (I) selecting one of said first and second sets of digital data to be compared with the reference data stored in step (D) in accordance with the memory stored programmed instructions; (J) comparing the set of digital data selected in step (I) with the data stored in step (D); and, (K) selectively activating an alarm based on the results of the comparison performed in step (J).