Measuring and testing – Vibration – By mechanical waves
Patent
1990-10-17
1992-11-03
Williams, Hezron E.
Measuring and testing
Vibration
By mechanical waves
73104, 73660, 340680, 340683, G01N 2914
Patent
active
051598361
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process for monitoring the chip-removing treatment of a workpiece, especially in lathe-turning, by analyzing the sound emission detectable on the tool, which is transformed with the aid of an electroacoustic transformer into an electrical sound-emission signal, which is filtered and compared with respect to its amplitude determined over a predetermined period of time with a predetermined adaptable threshold value.
Furthermore, the invention relates to a device for the execution of the process with an electroacoustic transformer arranged on the tool holder, converting the sound emission signal, which transformer, over a high-pass filter, an amplifier and a detector, feeds a mean-value former, the output signal of which feeds the first input of a comparator, the second input of which is actable-upon with a threshold value voltage.
Such a process and such a device are known from U.S. Pat. No. 4,332,161 and make it possible to generate an output signal on the output of a comparator when the tool wear has exceeded a prescribed degree. Since the sound-emission signal contains pulse-type chip-break signals, the frequency and amplitude of which do not associate directly and clearly with the tool wear and the processing quality, the output voltage of the integrator and, therefore, the switching-over of the comparator cannot be dependably allocated to a predetermined wear on the tool. The voltage standing on the output of the integrator does not change in dependence on the chip-break sequence and, therefore, is no dependable measure for the tool wear.
Proceeding from this state of the art, underlying the invention is the problem of creating a process and a device which makes it possible dependably to detect exactly all forms of wear and dependably to evaluate the chip-break behavior.
This problem is solved according to the invention in the process mentioned at the outset by the means that the constituents contained in the sound emission signal of the continuous basic noise signal resulting from the cutting noise and friction noise, on the one hand, and of the pulse-type chip-break signals superposed with respect to this with a higher amplitude, on the other hand, are separated and separately analyzed and also evaluated.
Included is the evaluation and monitoring of mean values, distribution of amplitudes, and of energies of impulses of chip break signals in order to monitor fluctuations of characteristic values of the processed workpiece and/or chip temperature changed in consequence of tool wear.
According to the invention there is continuously formed a noise mean value of the sound emission signal, in which, however, for the mean value formation there are not taken into account by blending-out those values of the sound emission signal which arise during the time windows allocated to the chip-break signals.
A device for the execution of the process is characterized in that to the mean-value former there is allocated a switch-over arrangement by which the feed of the mean-value former with the sound emission signal is interruptable during the pulse-type chip-break signals.
Through the fact that for the evaluation of the tool wear and of the processing quality the characteristic signal constituents are separated and separately analyzed as well as statistically evaluated, there is achieved a high dependability in the evaluation and the monitoring resulting therefrom.
Expedient embodiments and further developments of the invention are the object of subclaims.
In the following, the invention is explained in detail with the aid of an example of execution represented in the drawing.
FIG. 1 shows a block circuit diagram of a sound-emission analysis apparatus according to the invention and
FIG. 2 shows a block circuit diagram of the separating stage of the sound-emission analysis apparatus of the invention.
The sound emission analysis apparatus represented overall in the block circuit diagram in FIG. 1, for the monitoring of the chipping behavior and of the tool wear in a chip-removing treatment, e
REFERENCES:
patent: 4332161 (1982-06-01), Kakino
patent: 4413507 (1983-11-01), Drew et al.
patent: 4636779 (1987-01-01), Thomas et al.
patent: 4636780 (1987-01-01), Thomas et al.
patent: 4642617 (1987-02-01), Thomas et al.
patent: 4707687 (1987-11-01), Thomas et al.
patent: 4707688 (1987-11-01), Thomas
patent: 4831365 (1989-05-01), Thomas et al.
patent: 4849741 (1989-07-01), Thomas
patent: 4918427 (1990-04-01), Thomas et al.
Hepp Klaus
Waschkies Eckhard
Finley Rose M.
Fraunhofer-Gesellschaft zur Forderung Der Angewandten Forschung
Williams Hezron E.
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