JPH11123578A - Laser machining head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent scattering of spatters into a head while the head is formed small in the tip end. SOLUTION: This machining head 1 is constituted so that it is provided with inner and outer nozzles 5, 6 arranged in a double pipe shape, a laser beam L and an assist gas G1 are emitted and ejected from the inner nozzle 5 and an assist gas G2 is ejected from the outer nozzle 6. In this case, the exit 17a of the outer nozzle 6 is directed in the crossing direction against the exit 19 of the inner nozzle 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing head formed at the tip of a laser processing apparatus for performing laser processing such as welding.

[0002]

2. Description of the Related Art In recent years, laser processing has gradually become a general-purpose technique, and is replacing conventional methods in the field of welding and cutting.

[0003] However, this laser processing has practical problems to be solved.

[0004] The first problem is a problem peculiar to laser processing. A plasma plume is generated on a beam irradiation surface during the laser processing. The plasma plume obstructs a subsequent laser beam and causes energy loss. That is the problem. In particular, in the case of a CO ₂ laser,
The laser beam is refracted by the plasma plume, and a predetermined energy density cannot be obtained at the processing point, so that stable processing cannot be performed.

[0005] The second problem is a problem of lens contamination due to scattering of spatter, which is also observed during welding and cutting processing by the conventional method. In the case of laser processing, since a condensing lens is expensive, an assist gas is supplied to prevent adhesion of spatter. However, at present, it is not sufficient and a protective glass is used together. However, the frequency of replacing the protective glass is high, which is a bad effect of continuous processing, and increases running costs.

In order to address these problems, a laser processing apparatus as described below has been proposed.

For example, there is a laser processing head 51 as shown in FIG. The laser processing head 51 includes inner and outer nozzle bodies 52 and 53 arranged in a double tube.
A laser beam L and an assist gas G1 are emitted and ejected from the inner nozzle body 52, and an assist gas G2 is ejected from the outer nozzle body 53. In the figure, 61 indicates a condenser lens, and 62 indicates a protective glass.

The laser beam L emitted from the inner nozzle body 52 is applied to the work 54, and a plasma plume is generated at this time. The plasma plume is generated by the assist gases G1, G2 jetted from the inner and outer nozzle bodies 53, 54. Is to be removed.

There is also a laser processing head 55 as shown in FIG. The laser processing head 55 is provided with a shielding plate 56 for shielding sputter at its tip,
A plurality of gas ejection ports 57 for ejecting the assist gas G from the side of the irradiation surface of the work 54 and a plurality of air ejection ports 58 for ejecting the air A from the side are provided. In the drawing, reference numeral 59 denotes a condenser lens.

The sputter generated by the irradiation of the laser beam L is shielded by the shield plate 56 and is largely blown off by the assist gas G. Further, the sputter that has passed through the shield plate 56 and scattered on the upper side is And blown off by the air A spouted from the air.

[0011]

However, in the laser processing head 51 shown in FIG. 4, the assist gas G1 ejected from the inner nozzle body 52 and the assist gas G2 ejected from the outer nozzle body 53 are provided. Are effective only for removing the plasma plume because they are merely flowed in parallel and downward along the shape of the nozzle bodies 52 and 53, but they prevent spatter from adhering to the protective glass. Was not very effective against That is,
Since the mass or the momentum of the sputter is larger than that of the plume, the spatter cannot be prevented from scattering into the inner nozzle body 52 depending on the assist gases G1 and G2.

Further, in the laser processing head 55 shown in FIG. 5, the sputtering is shielded by the shielding plate 56 and blown off by the assist gas G and the air A. Further, since the lens is located at a long distance, Is effective in preventing adhesion of the laser processing head to the lens. However, since various parts such as the shielding plate 56, the gas outlet 57, and the air outlet 58 are provided at the tip of the laser processing head 55, The tip of the head becomes large, making it impossible to use it in three-dimensional welding of complicated shapes such as automobile assembly.

Accordingly, the present invention has been devised to solve the above-mentioned problem, and an object of the present invention is to provide a laser processing head capable of preventing the scattering of spatter into the head while forming the head tip portion small. To provide.

[0014]

In order to solve the above-mentioned problems,
The present invention provides an inner and outer nozzle body disposed in a double tubular shape, a laser processing in which a laser beam and an assist gas are emitted and ejected from an inner nozzle body, and an assist gas is ejected from an outer nozzle body. In the head, the outlet of the outer nozzle body is directed in a direction crossing the outlet of the inner nozzle body.

According to the above configuration, as in the conventional example shown in FIG.
The point that the tip of the head can be formed small by the inner and outer nozzle bodies is the same. In particular, in the above configuration, the assist gas ejected from the outer nozzle body is discharged in a direction intersecting with the assist gas ejected from the inner nozzle body to form a shielding curtain against spatter. Thereby, it is possible to prevent the spatters from entering and scattering inside the head.

It is preferable that the outer nozzle body is formed by bending its outlet portion inward in the radial direction.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of a laser processing head according to the present invention.

The illustrated laser processing head 1 is formed at the tip of a laser processing apparatus provided with a laser source (not shown) for generating a laser beam L.

The laser processing head 1 is provided with a nozzle holder 4 forming a body thereof. Inside the nozzle holder 4, the laser beam L is refracted on the upstream side of the flow of the laser beam L so as to be directed to the work 2. The condenser lens 3 to be irradiated is attached via a ring-shaped lens fixing member 7. Further, a protective glass 8 for protecting the condenser lens 3 from spatter or the like is attached to the downstream side of the condenser lens 3 via a ring-shaped glass fixing member 9.

Inner and outer nozzle bodies 5, 6 arranged concentrically and in a double tubular shape are fitted to the tip of the nozzle holder 4, and are provided so as to close the inside and outside. These nozzle bodies 5, 6
Has a tapered tip.

A first gas for supplying an assist gas G1 made of an inert gas such as argon or helium into the inside of the inner nozzle body 5 is provided in a portion of the nozzle holder 4 located upstream of the inner nozzle body 5. A supply port 11 is formed. A flange 12 is formed at the upstream end of the inner nozzle body 5,
On its upstream side, a ring member 13 is provided at a predetermined interval, and the gap forms a gas flow passage 20 for sending the assist gas G1 supplied from the first gas supply port 11 to the inside of the inner nozzle body 5. Has become. The space inside the inner nozzle body 5 is a first gas supply path 14 for flowing the assist gas G1 to the outlet 19 at the tip. The outlet 19 of the inner nozzle body 5 is directed in the axial direction, and the assist gas G
1 will be ejected along the axial direction.

The inner nozzle body 5 and the outer nozzle body 6 are fixed at a predetermined interval, and a gap is formed between the tip of the outer nozzle body 6 and an inert gas such as argon or helium, similar to the assist gas G1. A second gas supply path 15 for supplying an assist gas G2 made of gas is provided. In a portion of the nozzle holder 4 where the second gas supply path 15 is located, a second gas supply port 16 for supplying the assist gas G2 to the second gas supply path 15 is formed. An outlet 17a of the second gas supply passage 15 is formed in a portion sandwiched between the tip of the inner nozzle body 5 and the tip of the outer nozzle body 6, and extends over the entire circumferential direction of the tip of the inner nozzle body 5. It is formed.

The outer nozzle body 6 is bent radially inward so that the outlet 17b forming the outlet 17a of the assist gas G2 at the tip thereof covers the tip surface of the inner nozzle body 5 as a bent part 18. It is formed. The distal end surface 18b of the bent portion 18 is formed so as to coincide with the extension of the inner surface of the inner nozzle body 5, so as not to obstruct the flow of the assist gas G1. The inner peripheral surface at the base end of the bent portion 18 is formed in an arcuate cross section, so that the flow of the assist gas G2 is smooth.

By forming the bent portion 18 in this manner, the direction of the outlet 17a is directed radially inward and crosses the direction of the outlet 19 of the inner nozzle body 5 at right angles. Thereby, the assist gas G1 spouted from the first gas supply passage 14 inside the inner nozzle body 5 and the assist gas G2 spouted from the second gas supply passage 15 inside the outer nozzle body 6 are connected to the outlet 17a. At the exit downstream portion 24, which is a portion surrounded by a circle, crosses or collides at a right angle.

Next, the laser processing head 1 having the above configuration
The operation of will be described.

In order to perform laser processing such as welding, a laser beam L is generated from a laser source, the generated laser beam L is applied to the work 2 by the condenser lens 3, and the assist gases G1 and G2 are applied to the laser beam L. One gas supply port 11
And from the second gas supply port 16.

The assist gas G1 supplied from the first gas supply port 11 passes through the gas flow path 20 and the first gas supply path 14, and then blows out from the outlet 19 at the tip toward the work 2. Mainly, by the ejection of the assist gas G1 from the inner nozzle body 5, the plasma plume generated by the irradiation of the laser beam L can be blown off and removed. Thereby, energy loss of the laser beam L can be prevented.

On the other hand, the assist gas G2 supplied from the second gas supply port 16 passes through the second gas supply path 15,
It is ejected radially inward from the outlet 17a at the tip.
Mainly, a shielding curtain made of gas is formed at the outlet downstream portion 24 by the assist gas G2 ejected from the second gas supply passage 15. With this shielding curtain, of the spatters generated by the irradiation of the laser beam L, the spatters scattered toward the inside of the inner nozzle body 5 can be shielded, and contamination of the protective glass 8 due to the scattered spatters can be prevented. . Thereby, the protective glass 8
Can be reduced, continuous processing can be performed, and a reduction in running cost can be achieved. Note that the shielding curtain is formed in a shape slightly swelling downstream due to the flow of the assist gas G1.

FIG. 3 is a schematic view showing an example of laser processing using the laser processing head according to the present invention, and shows, for example, a typical cross section of a car structure (pillar).

As shown in FIG.
Since the tip is formed in a tapered nozzle shape, laser processing can be performed even in a complicated three-dimensional shape and a narrow portion as in the case where the inner panel 21 and the outer panel 22 are joined by welding. It can be carried out.

FIG. 2 is an enlarged sectional view of a main part showing another embodiment of the laser processing head according to the present invention.

In the laser processing head 1 shown in FIG. 1, the direction of the assist gas G2 ejected from the second gas supply passage 15 is set to be perpendicular to the axial direction of the inner and outer nozzle bodies 5, 6. The laser processing head 23 of the other embodiment of FIG. 2 reduces the bending angle of the bent portion 18 of the outer nozzle body 6 and gradually reduces the thickness toward the end, The direction of the outlet 17a of the two-gas supply path 15 is not perpendicular to the axial direction of the inner and outer nozzle bodies 5 and 6, but is directed slightly obliquely, and the ejection direction of the assist gas G2 is slightly downstream (the work 2 side). It is characterized by being directed to

Even if the ejection direction of the assist gas G2 is slightly directed to the downstream side, since the component directed inward in the radial direction is strong, a shielding curtain made of gas can be formed at the outlet downstream portion 24 in the same manner as the laser processing head 1. In addition, the spatter scattered toward the inside of the inner nozzle body 5 can be shielded. Moreover,
According to the above configuration, the flow of the assist gas G2 ejected from the second gas supply passage 15 is further smoothed.

In the laser processing heads 1 and 23 of the above embodiment, the outlet 17a of the assist gas G2 of the second gas supply path 15 is formed in the entire circumferential direction. Alternatively, a plurality of gas ejection holes may be formed.

[0036]

As described above, according to the present invention, an excellent effect of preventing the scattering of spatter into the inside of the head can be achieved while forming the head tip portion small.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a laser processing head according to the present invention.

FIG. 2 is an enlarged sectional view of a main part showing another embodiment of the laser processing head according to the present invention.

FIG. 3 is a schematic view showing an example of laser processing using the laser processing head according to the present invention.

FIG. 4 is a sectional view showing a conventional laser processing head.

FIG. 5 is a cross-sectional view showing another conventional laser processing head.

[Explanation of symbols]

 Reference Signs List 1 laser processing head 5 inner nozzle body 6 outer nozzle body 17a outlet 17b outlet 18 bent portion 19 outlet G1, G2 assist gas L laser beam

Claims (2)

[Claims] 1. A laser having an inner and outer nozzle body disposed in a double tubular shape, wherein a laser beam and an assist gas are emitted and ejected from an inner nozzle body, and an assist gas is ejected from an outer nozzle body. A laser processing head, wherein an outlet of an outer nozzle body is directed in a direction intersecting with an outlet of an inner nozzle body. 2. The laser processing head according to claim 1, wherein the outer nozzle body has an outlet portion bent radially inward.