US4960970A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for acoustic breakthrough detection
Assignee: General Electric Co
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Filing: 1989-08-11
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Granted: 1990-10-02
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Expires: 2009-08-11
Abstract
Abstract Apparatus for laser processing, such as drilling of a workpiece, optionally has an optical fiber and output coupler for applying laser light to machine a workpiece and cause it to vibrate. An acoustic sensor is mounted on the workpiece, and a determining means, such as a computer, determines when the vibrations change, such as when they cease. The information can be used to change the laser pulse power and duration and the relative distance of the laser focal plane on the workpiece. A method of laser processing a workpiece causes vibrations in the workpiece by applying laser light to it, monitors the vibrations, and determines when they change.
Inventors
- 👤 John L. Schneiter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:36
CPC Classifications
B; B23; B23K; B23K26/00; B23K26/36; B23K26/38; B23K26/382; B23K26/02; B23K26/03; B23K26/40; B23K2103/00; B23K2103/02; B23K2103/04; B23K2103/08; B23K2103/10; B23K2103/30; B23K2103/42; B23K2103/50
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
53 words
Apparatus for laser processing of a workpiece, said apparatus comprising: means for applying pulsed laser light to the workpiece to cause vibrations therein; means for acoustically monitoring said vibrations in the workpiece, said monitoring means comprising an accelerometer adapted to be mounted on the workpiece; and means for determining when said vibrations change.
Claim 2
Dependent Claim
53 words
Apparatus for laser processing of a workpiece, said apparatus comprising: means for applying pulsed laser light to the workpiece to cause vibrations therein; means for acoustically monitoring said vibrations in the workpiece, said monitoring means comprising an accelerometer adapted to be mounted on the workpiece; and means for determining when said vibrations change.
Claim 3
Dependent Claim
42 words
The apparatus of claim 1 wherein said applying means comprises an optical fiber having a first end for receiving laser light and a second end, and an output coupler coupled to said second end and adapted to be disposed proximate the workpiece.
Claim 4
Dependent Claim
56 words
Apparatus for laser processing of a workpiece, said apparatus comprising: means for applying pulsed laser light to the workpiece to cause vibrations therein; means for acoustically monitoring said vibrations in the workpiece; means for determining when said vibrations change; and an optical sensor adapted to be disposed in said laser and coupled to said determining means.
Claim 5
Dependent Claim
56 words
Apparatus for laser processing of a workpiece, said apparatus comprising: means for applying pulsed laser light to the workpiece to cause vibrations therein; means for acoustically monitoring said vibrations in the workpiece; means for determining when said vibrations change; and an optical sensor adapted to be disposed in said laser and coupled to said determining means.
Claim 6
Dependent Claim
26 words
The apparatus of claim 1 wherein said determining means comprises means for spectrally analysing said vibrations, and threshold means for deciding when the spectral content changes.
Claim 7
Dependent Claim
17 words
The apparatus of claim 4 wherein said means for determining comprises means for bandpass filtering said vibrations.
Claim 8
Dependent Claim
19 words
The apparatus of claim 5 wherein said bandpass filtering means has a passband between about 40 and 80 kHz.
Claim 9
Dependent Claim
23 words
The apparatus of claim 4 further comprising an optical sensor adapted to be disposed in said laser and coupled to said determining means.
Claim 10
Dependent Claim
24 words
The apparatus of claim 7 wherein said determining means determines the ratio of a vibration pulse length to that of a laser pulse length.
Claim 11
Dependent Claim
68 words
The apparatus of claim 1 further comprising means for focussing the laser light onto a focal plane, means for causing relative motion between said applying means and the workpiece coupled to said determining means to change the position of the focal plane with respect to the workpiece, and a controllable power supply coupled to the laser and said determining means for controlling the energy of the laser light.
Claim 12
Dependent Claim
51 words
Apparatus for determining breakthrough during pulsed laser drilling of a workpiece, said apparatus comprising: means for acoustically monitoring vibrations in the workpiece caused by the drilling, said monitoring means comprising an accelerometer adapted to be mounted on the workpiece; and means for determining when the spectral content of said vibrations changes.
Claim 13
Dependent Claim
51 words
Apparatus for determining breakthrough during pulsed laser drilling of a workpiece, said apparatus comprising: means for acoustically monitoring vibrations in the workpiece caused by the drilling, said monitoring means comprising an accelerometer adapted to be mounted on the workpiece; and means for determining when the spectral content of said vibrations changes.
Claim 14
Dependent Claim
19 words
The apparatus of claim 3 wherein said monitoring means comprises an accelerometer adapted to be mounted on the workpiece.
Claim 15
Dependent Claim
42 words
The apparatus of claim 3 wherein said applying means comprises an optical fiber having a first end for receiving laser light and a second end, and an output coupler coupled to said second end and adapted to be disposed proximate the workpiece.
Claim 16
Dependent Claim
26 words
The apparatus of claim 3 wherein said determining means comprises means for spectrally analyzing said vibrations, and threshold means for deciding when the spectral content changes.
Claim 17
Dependent Claim
17 words
The apparatus of claim 13 wherein said means for determining comprises means for bandpass filtering said vibrations.
Claim 18
Dependent Claim
19 words
The apparatus of claim 14 wherein said bandpass filtering means has a passband between about 40 and 80 kHz.
Claim 19
Dependent Claim
24 words
The apparatus of claim 3 wherein said determining means determines the ratio of a vibration pulse length to that of a laser pulse length.
Claim 20
Dependent Claim
68 words
The apparatus of claim 3 further comprising means for focussing the laser light onto a focal plane, means for causing relative motion between said applying means and the workpiece coupled to said determining means to change the position of the focal plane with respect to the workpiece, and a controllable power supply coupled to the laser and said determining means for controlling the energy of the laser light.
Claim 21
Dependent Claim
54 words
Apparatus for determining breakthrough during pulsed laser drilling of a workpiece, said apparatus comprising: means for acoustically monitoring vibrations in the workpiece caused by the drilling; means for determining when the spectral content of said vibrations changes; and an optical sensor adapted to be disposed in said laser and coupled to said determining means.
Claim 22
Dependent Claim
54 words
Apparatus for determining breakthrough during pulsed laser drilling of a workpiece, said apparatus comprising: means for acoustically monitoring vibrations in the workpiece caused by the drilling; means for determining when the spectral content of said vibrations changes; and an optical sensor adapted to be disposed in said laser and coupled to said determining means.
References Cited (Backward Citations)
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| 7.5 Years (Year 8) | 1997-10-01 | 1998-04-02 | 1998-10-02 | $3760.00 | Window Closed / Lapsed |
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