JPH11267874A - Laser processing nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the contamination of a protective glass by shielding a molten metal fully and increasing the spraying volume of an air knife in a laser processing nozzle. SOLUTION: By this laser processing nozzle, a laser light is condensed by a lens optical system 12 and ejected to a workpiece 13 so as to weld the workpiece. A protective glass 15 is arranged at the lower side of the lens optical system 12, and an air knife 14 is sprayed between the lens optical system 12 and the workpiece 13 from an air knife nozzle 14 in a manner to cross an optical axis of the laser light. The shield gas is sprayed to the workpiece 13 from a shield gas ejection port 16. An opening 17 is formed to a nozzle body 11 near the air knife nozzle 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a laser processing apparatus,
In particular, it relates to a laser processing nozzle used in a laser welding apparatus.

[0002]

2. Description of the Related Art In general, a laser welding apparatus irradiates a workpiece with laser light to perform welding or the like, and a laser welding apparatus uses a lens (not shown) for focusing laser light on the workpiece. Nozzle having an optical system).

When a workpiece is thermally processed (welded) by a laser welding apparatus, not only a plume (plasma-like gas body) is generated by a laser beam, but also fumes (fine powder of evaporated metal or the like) and spatters are generated. (Molten metal scattered) is generated. Therefore, such plumes, fumes, and spatters (hereinafter collectively referred to as spatters, etc.)
It is necessary to protect the lens optical system from Further, it is desired that the plume hinders laser light from reaching the surface of the workpiece and is removed.

Here, a conventional laser processing nozzle will be outlined with reference to FIG.

[0005] The illustrated nozzle has a nozzle housing 11, and a lens optical system 12 is mounted on the nozzle housing 11. Then, the laser light is condensed by the lens optical system 12 and irradiated on the workpiece (metal workpiece) 13, for example, by welding.

The nozzle housing 11 is provided with an air knife nozzle 14 to protect the lens optical system from plumes, fumes, and spatters. The air knife nozzle 14 has an air knife outlet 14a and an air knife outlet 14b.
The air knife outlet 14b is opposed to the air knife outlet 14a. Air (air knife) is fed into the lower side of the lens optical system 12 from the air knife outlet 14a as indicated by a thick arrow, and is discharged from the air knife outlet 14b. The lens optical system 12 is protected by the air knife (at this time, the plume is not actively removed).

Normally, the lens optical system 1 is used only with the air knife.
2 is not sufficiently protected, a protection glass 15 for protecting the lens optical system 12 is provided below the lens optical system 12.

At the tip of the nozzle housing 11, a shield gas outlet 16 for blowing a shield gas to the workpiece 13 is formed. This shield gas is for preventing the oxidation of the molten metal when the workpiece 13 is melted into the laser beam. As shown by the thin arrow, the shield gas is discharged from the air knife outlet 14b together with the air knife.

[0009]

By the way, it is difficult to completely shut off the spatter and the like with the air knife, so that the spatter and the like that could not be cut off with the air knife adhere to the protective glass 15. When the amount of adhesion to the protective glass 15 increases, irradiation of the workpiece 13 with laser light is hindered. For this reason,
It is necessary to appropriately replace the protective glass 15.

[0010] When such protection glass is replaced, laser processing or the like must be inevitably interrupted, resulting in a problem that the working efficiency is reduced.

In addition, in the case of a high-power laser, the protective glass 15 reflects the laser beam and may adversely affect the surroundings. For this reason, it is necessary to apply an AR coat (anti-reflection coat) suitable for the wavelength of the laser light to the protective glass. Such an AR-coated protective glass is expensive and cannot be replaced frequently. In other words, the protective glass is expensive for disposable use.

In order to extend the use time of the protective glass, it is necessary to strengthen the air knife. For this reason, when the gas flow rate of the air knife is increased by increasing the gas pressure at the air knife outlet, the above-mentioned shield gas is caught in the air knife, and a defective shield of the molten metal on the workpiece occurs. There is. Further, in order to positively control the removal of the plume, an air knife that is as close as possible to the workpiece and does not affect the shield is required.

In order to prevent entrapment of the shielding gas,
If the ejection pressure of the shielding gas is increased, then a turbulence is generated in the shielding gas flow, and the shielding gas flow entrains the surrounding atmosphere, resulting in defective shielding. In other words, it is necessary to flow the welding shield gas in a state of wrapping the molten metal softly.

In any case, in the conventional laser processing nozzle, it is necessary to blow the air knife with a blowing amount that does not affect the shielding gas, and it is necessary to secure an amount and a position necessary for removing the plume. There is a problem that it is difficult to do.

An object of the present invention is to provide a laser processing nozzle having a low exchange rate of protective glass.

Another object of the present invention is to provide a laser capable of sufficiently shielding molten metal, increasing the blowing amount of an air knife, and removing air by blowing air near a workpiece. An object of the present invention is to provide a processing nozzle.

[0017]

According to the present invention, there is provided a nozzle housing, and an optical system attached to the nozzle housing. A laser processing nozzle for irradiating and welding the workpiece, wherein an air flow is generated between the optical system and the workpiece so as to cross an optical axis of the laser light. Laser processing, comprising: a blowing nozzle; and a shielding gas supply unit for blowing a shielding gas to the workpiece, wherein an opening is formed in the nozzle housing in the vicinity of the air flow blowing nozzle. Nozzle is obtained.
A protective glass for protecting the optical system is provided between the air flow and the optical system.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

Referring to FIG. 1, the illustrated nozzle has a nozzle housing 11, and a lens optical system 12 is mounted on the nozzle housing 11. Then, the lens optical system 12
The laser beam is condensed and irradiated to the workpiece (metal workpiece) 13 by, for example, welding.

The nozzle housing 11 is provided with an air knife nozzle 14 to protect the lens optical system from plumes, fumes, and spatters. The air knife nozzle 14 has an air knife outlet 14a and an air knife outlet 14b.
The air knife outlet 14b is opposed to the air knife outlet 14a. Air (air knife) is fed into the lower side of the lens optical system 12 from the air knife outlet 14a as shown by a thick arrow, and is discharged from the air knife outlet 14b. Further, a protective glass 15 for protecting the lens optical system 12 is provided below the lens optical system 12.

At the tip of the nozzle housing 11, a shield gas outlet 16 for blowing a shield gas to the workpiece 13 is formed. This shielding gas is for preventing the oxidation of the molten metal when the workpiece 13 is melted by the laser beam.

Further, a cutout (opening) 17 is formed in the nozzle housing 11 below the air knife nozzle 14, and air (air) is supplied from the opening 17 in accordance with the flow of the air knife. You.

When a high-speed air knife is jetted from the air knife outlet 13a, gas around the air knife is drawn by the air knife and starts to move. On this occasion,
If the opening 17 is not formed, the shield gas will be sucked by the flow of the air knife. In addition, in FIG. 1, the flow of the air knife is drawn by arrows in a straight line, but in reality, the air knife has a wide-angle spread. As a result, the air knife collides against the outer wall of the nozzle housing 11, and the nozzle housing 1
Another flow occurs within one. As a result, the shielding gas is sucked by the air knife.

As shown in FIG. 1, when the opening 17 is formed, as a result of air flowing in from the opening 17, even if the blowing pressure of the air knife is increased, the shield gas is not sucked into the air knife.

As described above, in the illustrated example, since the opening is formed around the air knife outlet, the shield gas is not sucked even if the blowing pressure of the air knife is increased. Spatter or the like hardly adheres to the metal, and the molten metal can be sufficiently shielded. In addition, air can be blown out near the workpiece, and plume removal control can be performed.

FIG. 2 shows the result of measuring the suction pressure in the nozzle housing with respect to the blowing pressure of the air knife. The nozzle shown in FIG. 1 has a lower suction pressure than the nozzle shown in FIG. You can see that. That is, the blowing pressure of the air knife can be increased.

[0027]

As described above, according to the present invention, the pressure of the air knife can be set without considering the entrainment of the shielding gas. Even if the flow rate is increased, entrapment of the shielding gas is eliminated, and spatter or the like is less likely to be attached to the protective gas by the air knife, thereby reducing the exchange rate of the protective glass. In addition, air can be blown out near the workpiece, and there is an effect that plume removal control can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a laser processing nozzle according to the present invention, wherein (a) is a cross-sectional view as viewed from the side, and (b) is a diagram as viewed from above.

FIG. 2 is a diagram showing a result of measuring a relationship between a blowing pressure of an air knife and a suction pressure in a nozzle housing.

FIG. 3 is a view showing a conventional laser processing nozzle;
(A) is a cross-sectional view as viewed from the side, and (b) is a view as viewed from above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Nozzle housing 12 Lens optical system 13 Workpiece (metal workpiece) 14 Air knife nozzle 14a Air knife outlet 14b Air knife outlet 15 Protective glass 16 Shield gas outlet 17 Notch (opening)

Claims (2)

[Claims] 1. A nozzle housing, and an optical system attached to the nozzle housing, wherein the laser beam is condensed by the optical system and irradiated on the workpiece to weld the workpiece. A laser processing nozzle for generating an air flow across the optical axis of the laser light between the optical system and the workpiece, and a shield for the workpiece. A shielding gas supply unit for blowing gas, wherein an opening is formed in the nozzle housing in the vicinity of the air flow nozzle. 2. The laser processing nozzle according to claim 1, wherein a protective glass for protecting the optical system is provided between the air flow and the optical system. Laser processing nozzle.