CN106932382B - Method for judging laser cleaning effect - Google Patents
Method for judging laser cleaning effect Download PDFInfo
- Publication number
- CN106932382B CN106932382B CN201710259215.9A CN201710259215A CN106932382B CN 106932382 B CN106932382 B CN 106932382B CN 201710259215 A CN201710259215 A CN 201710259215A CN 106932382 B CN106932382 B CN 106932382B
- Authority
- CN
- China
- Prior art keywords
- signal
- laser
- time
- cleaning effect
- cleaning
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/71—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited
- G01N21/73—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited using plasma burners or torches
Landscapes
- Health & Medical Sciences (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Plasma & Fusion (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
Abstract
The invention relates to a method for judging laser cleaning effect through time-resolved spectroscopy. The method comprises the following steps: selecting a detection wavelength; irradiating the surface of an object to be cleaned by laser to obtain a plasma spectral line; acquiring a time-resolved spectrum signal at a selected wavelength; the cleaning effect is determined based on the time-varying characteristic of the acquired signal. The method judges the cleaning effect through the time-resolved spectrum, is a novel judging method, can judge the high repetition frequency laser cleaning effect in real time, quickly and accurately, provides a foundation for closed-loop control, greatly reduces the damage risk of the metal substrate, achieves the aim of high-efficiency cleaning, and has the characteristics of high efficiency, low manufacturing cost and the like.
Description
Technical Field
The invention belongs to the field of laser cleaning, and particularly relates to a method for judging laser cleaning effect.
Background
In recent decades, laser technology has penetrated into many high-tech fields, and laser cleaning is a new cleaning method to replace the traditional cleaning technology. The chemical solvent used in the traditional chemical cleaning method is volatile, causes harm to the health of operators and easily causes environmental pollution. Meanwhile, the chemical reagents are slow in reaction, often need to be heated, the cleaning efficiency is low, and the chemical residues can corrode the substrate to different degrees. The traditional physical removal method causes damage to the substrate in different degrees, is inconvenient for finish machining operation and has low efficiency. The laser cleaning technology utilizes a laser beam with high power density to irradiate the surface of a sample, so that the surface substance of the sample to be cleaned is stripped or ablated and the like to be separated from the surface of an object. The cleaning method is non-contact, can realize remote operation and high-efficiency and selective cleaning of pollutants, and does not damage the substrate. The laser cleaning can clean pollutants on the surfaces of various substrates, has little pollution to the environment, achieves high cleanliness and low cost, and has the advantages that the traditional cleaning method cannot compare with the traditional cleaning method.
In order to avoid damage to the substrate during laser cleaning, the laser fluence must be chosen between the cleaning threshold and the substrate damage threshold, and the appropriate exposure time (for a continuous laser) or number of pulses (for a pulsed laser) is used. When the laser energy density is too high or the action time is too long (the number of pulses for the pulsed laser is too large), damage to the substrate may be caused. In order to realize nondestructive cleaning, a technology capable of performing online detection on a laser cleaning effect is urgently needed, the laser cleaning state (during cleaning, after cleaning and damaged substrate) can be effectively judged, and the realization of full closed loop feedback control laser cleaning is supported. The laser cleaning detection method commonly used at present is a full spectrum judgment method and an image analysis method. The full spectrum judging method measures the plasma luminescence spectrum of the laser cleaning process through a spectrometer, and when the intensity of the spectral line corresponding to the substrate element reaches a certain intensity and the intensity of the spectral line corresponding to the object element to be cleaned is reduced to a certain degree, the cleaning is judged to be finished. However, the method has the disadvantages of low detection rate and high cost due to the characteristics and price of the spectrometer. The image analysis method is used for collecting the image of the surface of the part to be cleaned through a camera, and judging the cleaning effect through image analysis and recognition. The method is limited by the frame rate and price of the camera, and has the defects of low detection speed rate, complex algorithm and high cost. Both methods are difficult to realize the online monitoring of laser cleaning under high repetition frequency laser.
In order to solve the problems, the invention provides a method for judging the laser cleaning effect by using a spectral characteristic peak time resolution signal, and compared with a full spectrum and image judging method, the method has the advantages of high detection speed, low cost and capability of realizing online detection.
Disclosure of Invention
The invention aims to provide a method for judging laser cleaning effect, which judges the cleaning effect according to the time-varying characteristic of a signal by detecting a time-resolved signal of a characteristic element plasma spectrum of an object to be cleaned. Compared with a full spectrum and image recognition-based method, the method for judging the cleaning effect is greatly improved in speed, and online detection can be realized.
The invention relates to a method for judging laser cleaning effect, which judges the cleaning effect through a spectral characteristic peak time resolution signal, and the characteristic comprises the following steps:
s101, selecting a detection wavelength;
s102, irradiating the surface of an object to be cleaned by laser to obtain a plasma luminous spectral line;
s103, acquiring a time-resolved spectrum signal at the wavelength selected in S101;
s104 determines the cleaning effect from the time-varying characteristic of the acquired signal.
The method for determining the laser cleaning effect is characterized in that the detection wavelength is a plasma spectral line corresponding to one of elements contained in the surface to be cleaned.
The method for judging the laser cleaning effect is characterized in that the plasma luminescence is generated by cleaning a target object under the action of laser.
The method for determining the laser cleaning effect is characterized in that the laser is a pulse laser, the pulse width of the laser is shorter than a microsecond, and the laser can be output by a solid laser, a gas laser, a fiber laser, a semiconductor laser and the like.
The method for determining the laser cleaning effect is characterized in that the time-resolved spectrum signal is a change signal of light intensity at a selected wavelength along with time.
The method for determining the laser cleaning effect is characterized in that the time-varying characteristics of the signal are characteristics related to the time-varying signal, such as the service life of the signal and the strength of the signal after a certain delay.
The method for judging the laser cleaning effect is characterized in that the cleaning effect is judged according to the time-varying characteristic of the collected signals, namely the signal service life is shortened to be consistent with the inverse bremsstrahlung or the signal intensity is smaller than a set value after the time delay is longer than the quasi-bremsstrahlung service life, the cleaning is judged to be clean, and the cleaning is judged to be incomplete if the time delay is longer than the quasi-bremsstrahlung service life.
Due to the implementation of the technical scheme, compared with the prior art, the invention has the following advantages:
the method judges the cleaning effect through the time-resolved spectrum, is a novel judging method, can judge the high repetition frequency laser cleaning effect in real time, quickly and accurately, provides a foundation for closed-loop control, greatly reduces the damage risk of the metal substrate, achieves the aim of high-efficiency cleaning, and has the characteristics of high efficiency, low manufacturing cost and the like.
Drawings
FIG. 1 is a flow chart of a method for determining laser cleaning effectiveness according to the present invention;
FIG. 2 is a diagram of a method and apparatus for determining laser cleaning effect according to the present invention;
in the figure: 1-a laser, 2-a reflector, 3-a lens, 4-a sample, 5-a fiber probe, 6-a spectrum separation part, 7-a photoelectric detector and 8-a high-speed signal acquisition and processing module;
FIGS. 3 (a) - (d) are time characteristic curves of the paint at 375nm (corresponding to titanium element) of a plasma spectrum under the action of laser, which are respectively the time characteristic curves of the sample under the action of 1 pulse, 5 pulses, 10 pulses and 15 pulses in the example;
FIG. 4 shows the effect of the paint after washing, wherein (a) is 10 pulses and (b) is 15 pulses.
Detailed Description
The invention relates to a laser cleaning effect judging method based on a time-resolved spectrum.
The cleaning effect is judged according to the time-varying characteristic in two modes, one mode is that the cleaning effect is judged according to whether the service life of the signal is shortened to be consistent with the inverse bremsstrahlung, namely whether the service life of the signal is consistent with a set value or not, if the service life of the signal is longer than the set value, the cleaning effect is not cleaned, and if the service life of the signal is shorter than or equal to the set value, the cleaning effect is cleaned; the other is that the signal is not cleaned if the signal strength is less than the set value after the delay time is greater than the service life of the bremsstrahlung, that is, the strength of a certain delay time point of the signal is consistent with the set value, if the signal strength is greater than the set value, the signal is not cleaned, and if the signal strength is less than or equal to the set value, the signal is cleaned. In order to obtain a good signal-to-noise ratio, the set value may be set to be more than 2 times the noise signal of the detector when no light signal is input.
FIG. 2 is a diagram of a method and apparatus for determining laser cleaning effect according to the present invention, wherein a laser beam emitted from a laser 1 used for cleaning is focused on the surface of a cleaning object 4 through a reflector 2 and a lens 3 to generate plasma, the plasma light is transmitted into a spectrum separation part 6 through an optical fiber probe 5, and light with a wavelength corresponding to a preselected characteristic element passes through the spectrum separation part to reach a detector surface 7; the detector converts the optical signal into an electrical signal, and the electrical signal is sampled and analyzed by the high-speed data acquisition module 8. If the signal life is shortened to be consistent with the bremsstrahlung or the signal intensity is smaller than a set value after the time delay is longer than the bremsstrahlung life, the cleaning is judged to be clean, and if not, the cleaning is judged to be incomplete. The spectrum separation part 6 can be a monochromator or a narrow-band filter corresponding to the characteristic wavelength to be measured.
Example 1
In the embodiment, a laser 1 adopts a Q-switched Nd (yttrium aluminum garnet) pulsed solid-state laser with the wavelength of 1064nm, the pulse width of 7ns, the frequency of 1-100 Hz, the energy range of 0-100 mJ, and the laser is focused on a white paint sample through a lens to generate laser plasma; the reflector 2 adopts a dielectric film coated lens which is totally reflective to 1064nm wavelength 45 degrees; the lens 3 adopts a lens with a focal length of 200 mm; the Al substrate adopted by the bottom plate of the sample 4 is a white automatic paint spraying produced by Procili corporation, and the paint is uniformly sprayed on the surface of the substrate and has the thickness of about 150 mu m; the diameter of the optical fiber probe 5 is 400μm; the spectral separation part 6 adopts a grating spectrometer with the model of Acton SP2750 from Princeton Instruments; the photoelectric detector 7 adopts a THORLABS detector with the model number of APD430A2(/ M), the detection range is 200 and 1000nm, and the bandwidth is 400 MHz; the high-speed data acquisition processing module 8 adopts a high-speed acquisition instrument with the model number of ADQ412 manufactured by Beijing Kunshi company.
Specifically, a laser emits a light beam, and the light beam is focused on the surface of a target cleaning sample through a lens to form a laser-induced breakdown plasma spectrum. The initial reverse bremsstrahlung electron radiation can cause continuous background light, and the characteristic spectrum of atoms is easily submerged in the continuous background light. Because the background light intensity decays quickly and the atomic characteristic spectrum radiation intensity decays slowly, the ratio of the atomic characteristic spectrum signal to the background gradually increases with the time. The plasma luminescence of the metal substrate under the action of laser pulse is also quasi-bremsstrahlung, and the metal substrate has the characteristics of high intensity and short duration. The sources of the signals can be distinguished according to the time-varying characteristics of the signals, and the cleaning effect is judged; in the embodiment, the titanium element in the paint is selected as a characteristic element, and the characteristic peak value of the element at 375nm is selected.
Further, the plasma spectrum is transmitted into a spectrum separation part by using an optical fiber probe, a spectral line of a characteristic element titanium at 375nm is separated and sent to the surface of a detector, the detector converts an optical signal into an electric signal, and the signal is analyzed and processed by a high-speed data acquisition module; the time-varying pattern of the collected signals is shown in fig. 3, in which (a) is a signal detected at 1 pulse, (b) is a signal detected at 5 pulses, (c) is a signal detected at 10 pulses, and (d) is a signal detected at 15 pulses.
It can be seen that the time varying signal varies gradually from (a) to (d), and it can be seen that the background signal is substantially continuous for 10 pulses and is already evident for 15 pulses. According to the time-varying characteristic of the signal curve, the signal begins to change when the laser acts on the paint surface, the paint begins to be cleaned gradually along with the increase of the pulse number, the signal also begins to evolve towards the continuous background signal at the moment until the signal completely evolves into the continuous background light, and the paint is completely cleaned in the process.
The cleaning effect graphs of 10 pulses and 15 pulses after laser cleaning are further compared, as shown in fig. 4; it can be seen that when the laser pulse is 10 pulses, the paint has been completely cleaned, and at 15 pulses, the substrate has been damaged; setting the signal life of a time characteristic curve after 10 pulses act and the signal intensity of a certain delay point as initial values, and judging the laser cleaning effect in two ways; one is that after the continuous background light generated by the reverse bremsstrahlung (the reverse bremsstrahlung time of the embodiment is about 500 ns) disappears, the signal life is used for judging, if the signal life is greater than a set value (500 ns), the cleaning is not performed, and if the signal life is less than or equal to the set value, the cleaning is performed; the other is to determine the signal intensity according to a certain delay time (in this embodiment, 1 μ s), and if the signal intensity is greater than a set value (6.15 mv), it means that the cleaning is not performed, and if the signal intensity is less than or equal to the set value, it means that the cleaning is performed. Therefore, the cleaning effect can be accurately and quickly judged according to the time resolution spectrum, and the method has important significance for judging the laser cleaning effect.
In conclusion, the cleaning effect can be rapidly and accurately judged by the method of laser-induced breakdown time resolution spectroscopy.
Claims (4)
1. A method for judging laser cleaning effect is characterized in that a spectral characteristic peak time resolution signal is adopted to judge the cleaning effect, the laser is pulse laser, and the method comprises the following steps:
s101, selecting a detection wavelength, wherein the detection wavelength is a plasma spectral line corresponding to one of elements contained in a surface or a substrate to be cleaned;
s102, irradiating the surface of an object to be cleaned by laser to obtain a plasma luminous spectral line;
s103 acquires the time-resolved signal at the wavelength selected in S101: separating light emitted by the plasma through a spectrum separation part to obtain a light signal at the wavelength selected in S101, converting the light signal into an electric signal after the light signal reaches a detector, and sampling and analyzing the electric signal through a high-speed data acquisition module;
s104, judging the cleaning effect according to the service life of the acquired signal, the signal strength after 1 mu S time delay and other time-varying characteristics.
2. The method of claim 1, wherein the plasma emission is generated directly by the laser action on the cleaning target.
3. The method of claim 1, wherein the time-resolved signal is a time-varying signal corresponding to the peak intensity of the peak of the element characteristic of the object or substrate to be cleaned.
4. The method for determining laser cleaning effect according to any one of claims 1-3, wherein the determination of cleaning effect is performed according to the time-varying characteristics of the collected signals, that is, the signal lifetime is shortened to be consistent with the bremsstrahlung radiation or the signal intensity is less than the set value after the time delay is greater than the bremsstrahlung radiation lifetime, then the cleaning is determined to be clean, otherwise, the cleaning is determined to be incomplete.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710259215.9A CN106932382B (en) | 2017-04-20 | 2017-04-20 | Method for judging laser cleaning effect |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710259215.9A CN106932382B (en) | 2017-04-20 | 2017-04-20 | Method for judging laser cleaning effect |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106932382A CN106932382A (en) | 2017-07-07 |
| CN106932382B true CN106932382B (en) | 2020-10-09 |
Family
ID=59437827
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710259215.9A Active CN106932382B (en) | 2017-04-20 | 2017-04-20 | Method for judging laser cleaning effect |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106932382B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108544090B (en) * | 2018-04-19 | 2020-06-16 | 广州德擎光学科技有限公司 | Laser processing state identification method under spectral ion state |
| CN109365410B (en) * | 2018-10-17 | 2020-09-18 | 北京航天控制仪器研究所 | Processing head device for realizing efficient laser cleaning and cleaning method |
| CN110653223B (en) * | 2019-09-26 | 2021-10-29 | 厦门理工学院 | Laser cleaning monitoring device and monitoring method thereof and laser cleaning machine |
| CN113102387A (en) * | 2021-03-26 | 2021-07-13 | 国网上海市电力公司 | Laser decontamination method for electric power product |
| CN113305106B (en) * | 2021-06-03 | 2022-08-02 | 四川大学 | Method for cleaning micro-nano particle pollutants by laser and application |
| CN113533304B (en) * | 2021-07-06 | 2023-03-17 | 长江大学 | Method and device for judging laser descaling effect |
| CN114345840B (en) * | 2021-12-29 | 2022-12-27 | 北京航空航天大学合肥创新研究院(北京航空航天大学合肥研究生院) | Online optimization method for energy density in process of cleaning high-temperature oxide layer on surface of stainless steel by pulse laser |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4750822A (en) * | 1986-03-28 | 1988-06-14 | Therma-Wave, Inc. | Method and apparatus for optically detecting surface states in materials |
| CN102735658A (en) * | 2012-07-17 | 2012-10-17 | 中国科学技术大学 | Time resolution laser-induced breakdown spectroscopy measuring method |
| CN104730040A (en) * | 2013-12-18 | 2015-06-24 | 王宏 | Portable laser induced spectrum detection system |
| CN106033057A (en) * | 2015-03-10 | 2016-10-19 | 中国科学院微电子研究所 | Nondestructive rapid online detection method and system for particle pollution components on surface of silicon wafer |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001071164A (en) * | 1999-09-07 | 2001-03-21 | Mitsubishi Heavy Ind Ltd | Method for monitoring of part to be worked and device therefor |
| JP2002159926A (en) * | 2000-11-27 | 2002-06-04 | Japan Steel Works Ltd:The | Device and method for detecting cleaned state of substrate surface during laser cleaning |
| JP2003042967A (en) * | 2001-07-27 | 2003-02-13 | Hitachi Ltd | Inspection device for pattern defect |
| JP5086841B2 (en) * | 2008-02-29 | 2012-11-28 | 三菱重工業株式会社 | Gas monitoring system for processing equipment |
| CN105717135A (en) * | 2015-11-11 | 2016-06-29 | 南开大学 | Hyperspectral imaging-based method for monitoring laser cleaning process |
-
2017
- 2017-04-20 CN CN201710259215.9A patent/CN106932382B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4750822A (en) * | 1986-03-28 | 1988-06-14 | Therma-Wave, Inc. | Method and apparatus for optically detecting surface states in materials |
| CN102735658A (en) * | 2012-07-17 | 2012-10-17 | 中国科学技术大学 | Time resolution laser-induced breakdown spectroscopy measuring method |
| CN104730040A (en) * | 2013-12-18 | 2015-06-24 | 王宏 | Portable laser induced spectrum detection system |
| CN106033057A (en) * | 2015-03-10 | 2016-10-19 | 中国科学院微电子研究所 | Nondestructive rapid online detection method and system for particle pollution components on surface of silicon wafer |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106932382A (en) | 2017-07-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106932382B (en) | Method for judging laser cleaning effect | |
| CN101620183B (en) | Photoelectric double-pulse laser induced breakdown spectrograph and spectral analysis method | |
| JP2021530670A (en) | Second Harmonic Generation (SHG) Optical Inspection System Design | |
| CN107782715B (en) | Method for detecting components of steel sample by adopting multi-pulse laser-induced plasma spectral analysis equipment | |
| CN107064111B (en) | High-repetition-frequency laser stripping-spark induced breakdown spectroscopy element analysis system and method | |
| CN110582833A (en) | Sample inspection device and sample inspection method | |
| CN109030466A (en) | A kind of laser breakdown spectral measurement system based on beam shaping | |
| CN103278309B (en) | Optical component body inner laser damages automatic quick detection device | |
| CN105067572A (en) | Method and device for enhancing laser-induced plasma signal | |
| Yu et al. | Surface-enhanced laser-induced breakdown spectroscopy utilizing metallic target for direct analysis of particle flow | |
| JP2009288068A (en) | Analyzing method and analyzer | |
| CN110927170B (en) | Defect determination method, device and system | |
| CN112255191A (en) | Laser-induced breakdown spectroscopy and acoustic reflection combined online monitoring system and method | |
| Bredice et al. | Characterization of pulsed laser generated plasma through its perturbation in an electric field | |
| CN201449373U (en) | Photoelectric double-pulse laser induced breakdown spectrometer | |
| CN104515754B (en) | Laser plasma spectrometry device | |
| JP4286164B2 (en) | Laser processing monitoring system | |
| CN110000162A (en) | The method of Investigation of Laser Delacquer-ing effect is determined using vibration signal | |
| CN108333161B (en) | Pulse laser multiple round trip utilization device based on optical fiber and fluorescence signal detection method | |
| CN108761580B (en) | Optical film strengthening method and laser strengthening device | |
| Alvarez et al. | Spectral and electrical characterization of an aluminum plasma laser between the flat plates of a capacitor | |
| Richman et al. | Method for studying laser-induced damage from sparse defects | |
| Eriksson et al. | Basic study of photodiode signals from laser welding emissions | |
| CN207036695U (en) | Gao Zhongying laser lift-off spark induced breakdown spectroscopy elemental analysis system | |
| JP6027459B2 (en) | Deposit analyzer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |