JPH09122939A - Method and device for laser cleaning - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely separate and remove attached stuff without degenerating or wearing the surface of a work to be cleaned. SOLUTION: The continuous short-pulse laser beam to be outputted from a laser beam oscillation unit 12 is fed to a laser beam irradiator 16 through an optical transmission tube 32, and the surface of the work to be cleaned is irradiated with the short-pulse laser beam from the irradiator 16. The intermittent thermal shock wave is generated on the surface by the irradiation of the short-pulse laser beam on the surface of the work to be cleaned. The thermal shock wave generates the fine resonance, and the attached stuff is separated and removed from the surface of the work to be cleaned by this resonance effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser cleaning method and apparatus, and more specifically, it removes and removes deposits adhering to the surface of an object to be cleaned by using a low-power short pulse laser beam. The present invention relates to a laser cleaning method and device.

[0002]

2. Description of the Related Art For example, in a molding die made of rubber or resin, since the die is used a plurality of times, it is necessary to remove material scraps adhering to the molding die after releasing the product. There is. Further, the coating applied to structural materials such as bridges and steel towers needs to be repainted because it deteriorates with time. In that case, the old paint is removed and then repainted. In addition, "soot" attached to the surface of various articles,
There is a demand in many fields to remove deposits such as "rust", "carbide" or "resin". As described above, as a method of removing various kinds of adhered matters adhering to the surface of various articles (objects to be cleaned), water is sprayed onto the object to be cleaned at high speed, and the adhered matters are removed by water pressure. Method,
A method of spraying or applying chemicals on the surface of the object to be cleaned to remove the adhered matter by a chemical reaction, a fine powder is jetted at a low pressure to the object to be cleaned, and the adhered matter is removed by the grinding action of the powder. There is a known method (microblasting method), a method of ejecting abrasives such as sand and powder at high speed to the object to be cleaned, and removing adhered substances by the grinding action of the abrasive (shot blasting method). Has been.

[0003]

In the method using water as described above, the water-soluble salts can be removed without altering the surface condition of the object to be cleaned,
Since water may permeate into the object to be cleaned and salts may permeate due to the hydraulic effect, there is a problem that the target object to be cleaned is limited. Further, it is pointed out that a large amount of water containing the adhered substances removed from the object to be cleaned causes a complicated treatment of the sewage.
In the method using chemicals as described above, it is possible to surely remove the adhered substances by using the chemicals adapted to the target adhered substances. However, depending on the chemicals, it may take a long time to remove the adhered substances and may chemically damage the surface layer of the cleaning target. Also,
It is pointed out that some of them contain harmful substances to the human body, so that the workability during implementation is low, and the post-treatment of the chemical waste liquid is complicated. In the method using the fine powder as described above, the attached matter can be surely removed from the object to be cleaned and the precise cleaning can be performed. However, there is a risk that the surface of the object to be cleaned will be worn away, and thus accurate control of the instrument used is required. Moreover, since a large amount of fine powder is used, it is pointed out that there is a problem that leads to dust pollution. Furthermore, in the method using the abrasive as described above, it is possible to remove the adhering matter from the object to be cleaned efficiently and reliably. However, as with the method, there is a risk that the surface of the object to be cleaned will be worn away,
There is also a problem that dust pollution occurs due to the use of a large amount of abrasives.

As described above, various conventional methods for removing the adhering substances adhering to the surface of the object to be cleaned are limited in the objects that can be cleaned, the workability is poor, and a large amount of polluted water or dust is polluted. However, there are inherent problems that post-processing becomes complicated due to the above problems. That is, there is no cleaning method which has a wide application range, excellent workability, and easy post-treatment.

[0005]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned drawbacks inherent in the prior art, and it is possible to modify or abrade the surface of an object to be cleaned. It is an object of the present invention to provide a laser cleaning method and an apparatus that are excellent in workability and do not generate sewage or waste liquid.

[0006]

In order to overcome the above problems and preferably achieve the intended purpose, a laser cleaning method according to the present invention is applied to a low-power short pulse laser beam oscillated from a laser oscillator. By irradiating the surface of the object to be cleaned, an intermittent thermal shock wave is generated on the surface of the object to be cleaned and a minute resonance is caused, and the minute resonance of the thermal shock wave causes the object to be attached to the surface of the object to be cleaned. It is characterized in that the kimono is peeled off.

Further, a laser cleaning apparatus according to another invention of the present application for suitably carrying out the above-mentioned method is a laser oscillator for oscillating a low-output short-pulse laser beam, and a short-pulse laser output from the laser oscillator. It is characterized by comprising a laser irradiation gun for irradiating an object to be cleaned with a beam, and a lens capable of adjusting a focal length of a pulse laser beam irradiated from the laser irradiation gun.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a laser cleaning method according to the present invention will be described below with reference to a preferred embodiment in relation to an apparatus capable of suitably carrying out the method.
FIG. 1 shows a schematic configuration of a laser cleaning device according to an embodiment of the present invention. The laser cleaning device 10 includes a laser oscillation unit 12, a laser irradiator 16, a power supply unit 18, and a chiller unit 2.
Basically consists of 0.

The laser oscillating unit 12 comprises a laser oscillator 22 having a laser light source housed therein and a pulse generating unit 30 (Q switch). The laser oscillator 22 oscillates as a short pulse laser beam.
The oscillation frequency can be changed from several Hz to several tens Hz by changing the charge to the Q switch. However, when the pulse width of the beam becomes large, the thermal shock wave described later does not resonate efficiently, so the beam pulse width becomes 1
It is recommended to set 0 nanosecond or less, preferably 5 nanosecond or less.

The short pulse laser beam output from the laser oscillation unit 12 is supplied to the laser irradiator 16 through the light transmission tube 32. As shown in FIG. 2, the laser irradiation device 16 includes a laser irradiation gun 34.
And a lens 36 for adjusting the focal length of the beam,
An optimum focal length can be set by moving and adjusting the lens 36. Then, by varying the focal length of the pulsed laser beam, it is possible to vary the intensity of the energy density with respect to the surface of the object to be cleaned 24. Therefore, the object to be cleaned 24
By changing the energy density depending on the material, the amount of the adhered matter, the degree of the adhered matter, etc., the adhered matter can be efficiently peeled and removed without deteriorating or abrading the surface of the object to be cleaned 24. The energy density can be changed by disposing an appropriate filter between the laser irradiation gun 34 and the object to be cleaned 24. Further, as the light transmission tube 32, an articulated tube is preferably used, and is configured so that the short pulse laser beam can be easily irradiated over the entire surface of the object to be cleaned 24.

The chiller unit 20 functions to cool the laser oscillation unit 12 and perform laser oscillation under optimum conditions. In the apparatus of the embodiment, the temperature of the laser oscillation unit 12 is set to, for example, 19 ° C
It is set to hold within ± 1 ° C.

[0012]

Next, the operation of the laser cleaning device of the above-described embodiment will be described. A low power continuous short pulse laser beam is oscillated from the laser oscillation unit 12. The short pulse laser beam is applied to the surface of the object to be cleaned 24 via the laser irradiator 16. In the laser irradiator 16, the pulse interval and the focal length are adjusted to optimum values according to the material of the object to be cleaned 24, the amount of adhered matter, the degree of adherence, and the like.

Here, on the surface of the object to be cleaned 24 irradiated with the short pulse laser beam, a thermal shock wave (physical effect of light by the short pulse laser) is generated with the irradiation of the beam. Since the laser beam emitted from the laser irradiator 16 to the object to be cleaned 24 is pulsed, the surface of the object to be cleaned 24 is repeatedly irradiated and stopped by the surface of the object to be cleaned 24. A thermal shock wave will be generated intermittently. As a result, the thermal shock wave causes a slight resonance, and the resonance action causes the adhered matter to be peeled off from the surface of the object to be cleaned 24.

That is, in the laser cleaning apparatus 10 of the embodiment, since the low-output short pulse laser beam is used, the surface of the article to be cleaned 24 is not deteriorated or deteriorated by the heat effect, and only the adhered matter is removed. It can be removed by peeling. Further, the output of the laser is low, and since no consumable material such as water, chemicals or powder is used to remove the deposits, the running cost can be kept low. Further, during use, pollution such as sewage, waste liquid of chemicals, dust and the like does not occur, and the worker can work in a good environment. Furthermore, since the object can be irradiated with the laser beam in a pinpoint manner, it is possible to reliably peel off and remove the adhered matter on the narrow portion or the fine portion of the object to be cleaned 24.

Since the surface of the object is not deteriorated, deteriorated or worn away, it can be suitably used for cleaning stone statues and works of art. If the object to be cleaned 24 is soft like a semiconductor lead, the energy density can be reduced by shifting the focus of the laser beam to remove only the adhered material without damaging the surface or the entire surface. Is possible.

[0016]

As described above, according to the laser cleaning method and apparatus of the present invention, since the surface of the object to be cleaned is not brought into contact with water, chemicals or powder, the surface of the object to be cleaned is altered. It is possible to surely remove and remove the deposit without causing deterioration or abrasion. Further, since the laser beam used has a low output and does not use consumable materials such as water, chemicals or powders, it is possible to keep running costs low. Furthermore, since pollution such as sewage, waste liquid of chemicals or dust does not occur during use, the post-treatment work can be simplified and the worker can work in a good environment.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a laser cleaning device according to an embodiment of the present invention.

FIG. 2 is a mechanism explanatory view of a laser cleaning device.

[Explanation of symbols]

 20 Chiller unit 22 Laser oscillator 24 Cleaning object 34 Laser irradiation gun 36 Lens

Claims (3)

[Claims] 1. The surface of the object to be cleaned (24) is intermittently heated by irradiating the surface of the object to be cleaned (24) with a low-power short pulse laser beam emitted from a laser oscillator (22). A laser cleaning method, characterized in that a shock wave is generated and a minute resonance is generated, and by the minute resonance of the thermal shock wave, an adhered matter adhering to the surface of the object to be cleaned (24) is peeled off. 2. A laser oscillator (22) that oscillates a low-power short pulse laser beam, and a laser irradiation gun that irradiates an object (24) with the short pulse laser beam output from the laser oscillator (22). A laser cleaning device comprising: 34) and a lens (36) capable of adjusting a focal length of a pulse laser beam emitted from the laser irradiation gun (34). 3. The laser cleaning apparatus according to claim 2, wherein the laser oscillator (22) is cooled and maintained at a required temperature by a chiller unit (20).