JPH05200571A - Laser beam welding machine - Google Patents

Abstract

PURPOSE:To uniformly weld with laser beam at the welding surface of I-shape by providing the plasma removing nozzle adjoining to the laser beam machining head, forming the top opening part of nozzle to the slit shape and injecting the shield gas in the curtain like. CONSTITUTION:A plasma removing nozzle 21 is attached to a fittings 19 by adjoining to a laser beam machining head 15. Because the opening part is formed in the shape at the nozzle head 21, the shield gas G is slit curtain like from the direction of 40-60 degree against the LB. With this curtain like gas flow, the irradiating laser beam plasma P generated between head 15 and the metal sheet W is removed, the narrow welding surface of I-shape is formed at the butted surfaces of the metal sheet with the laser beam LB.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser welding apparatus for laser welding a butt portion of a plate material.

[0002]

2. Description of the Related Art Conventionally, it is generally well known that a butt portion of a plate material is irradiated with a laser beam from a laser processing head to perform laser welding on the plate material.

In this laser welding process, as shown in FIG. 7, when the laser beam LB is irradiated from the laser processing head to the abutting portion of the plate material W under a high density condition, the plate material W is
A high-intensity plasma P is generated above the abutting part of.
If this plasma P is left as it is, part of the laser beam LB that is subsequently irradiated is absorbed by the plasma P, and part of the laser beam LB is scattered and does not reach the melting spot. Therefore, the melting of the plate material W is delayed.

In order to carry out stable and continuous laser welding without stagnation of melting of the plate material W, it is necessary to remove the plasma P. In order to remove the plasma P, a plasma removal nozzle having an opening with a round cross section is provided beside the laser processing head.

[0005]

By the way, as shown in FIG. 7, from the plasma removing nozzle having a round cross section provided on the side of the above-described conventional laser processing head, toward the plasma P generated at the time of laser welding. the shielding gas G is caused to jet even trying to remove the plasma P, since the heat from the plasma P surfaces of the sheet W not fully cooled, the upper portion of the heat-affected zone W _B which is formed around the molten portion W _a There was a problem that it became a V-shape and became a V-shaped weld.

In order to solve the above problems, the object of the present invention is to eliminate the V-shaped welding by removing the plasma generated during laser welding, and to provide a uniform welding surface with a narrow welding width and an I-shaped welding surface. It is to provide a laser welding apparatus capable of performing laser welding.

[0007]

In order to achieve the above object, the present invention is directed to irradiating a laser beam from a laser processing head to a butt portion of a plate material and moving the laser processing head along a butt line in the butt portion. A laser welding device for performing laser welding on a plate material, which is provided with a plasma removing nozzle adjacent to the laser processing head for removing plasma generated during laser welding, and a tip opening portion of the plasma removing nozzle, A laser welding device was constructed by forming a shield gas in a slit shape so as to direct the shield gas toward the plasma in a curtain shape.

[0008]

By employing the laser welding apparatus of the present invention, the laser beam is emitted from the laser processing head toward the butt portion of the plate material and the laser processing head is moved along the welding line at the butt portion of the plate material. Laser welding is performed on the plate material.

Plasma generated during laser welding is directed toward the plasma from a tip opening portion formed in a slit shape of a plasma removing nozzle provided adjacent to the laser processing head, and a shield gas is ejected in a curtain shape. This removes the plasma. Thus, the welding width is narrow and an I-shaped welding surface is formed, and uniform laser welding is performed.

[0010]

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

Referring to FIG. 5, the laser welding apparatus 1 includes a work table 3. The work table 3 is configured in a gate shape and has side frames 3R and 3L.
And upper frame 3U. A groove 5 having a slight step is formed in the lower portion of the upper frame 3U substantially in the center in the X-axis direction. A notch portion 5G for back shield gas is formed in the front portion of the groove portion 5.

A back shield gas introduction hole 7 is provided in the Y-axis direction, which is the front-rear direction of the central portion of the groove portion 5, and communicates with the notch portion 5G. On the front side of the upper frame 3U, a notch 9 is formed extending in the left-right direction for positioning the plate material.

With the above structure, the plate member W is provided with a notch portion 9 formed on the upper frame 3U of the work table 3.
Then, the back surface of the plate material W is brought into contact with the protruding portion 3T, and the end surface of the plate material W is butted in the cutout portion 5G.
Further, the plate material W is positioned and fixed on the work table 3 by fixing the upper surface of the plate material W with the plurality of plate material fixing arms 11 from above the left and right sides of the upper frame 3U.

A main body frame 13 (only part) of the laser welding apparatus 1 is provided above the work table 3, and the main body frame 13 has a laser processing head movable in the X-axis and Y-axis directions, for example. 15 are provided.
The mechanism for moving the laser processing head 15 in the X-axis and Y-axis directions is performed by a well-known ball screw, rack, pinion or the like, and detailed description thereof will be omitted.

A condenser lens (not shown) is provided in the laser processing head 15, and a laser nozzle 17 is provided at the tip (lower end) of the processing head 15.

With the above structure, the laser beam oscillated from the laser oscillator (not shown) is condensed by the condenser lens in the laser processing head 15, and is further irradiated from the laser nozzle 17 to the abutting surface of the plate W, and at the same time, argon is emitted. Laser welding is performed by spraying a shielding gas such as nitrogen.

When performing laser welding on the abutting surface (welding portion) of the plate material W, the laser beam and the shield gas are irradiated from the laser nozzle 17 and the seal gas is supplied to the welding side (upper surface) to create an atmosphere at the side of the welding. The welding atmosphere is stabilized and laser welding is performed by stabilizing and further supplying the shielding gas from the back shield gas introduction hole 7 to the penetrating side (lower surface) to the notch 5G.

As a result, the welded portion (bead) and the heat effect are small, and the butt surface of the plate material W can be joined with almost no deformation of the welded portion. The same shape and the same mechanical strength as the material can be obtained. Furthermore, it is not necessary to apply an external force to the plate material W during welding, and deformation after welding hardly occurs. Therefore, the plate material fixing arm 1 that simply holds the plate material W is used.
It can be joined by a jig according to 1.

As shown in FIG. 1, a plasma removing nozzle 21 is mounted adjacent to the laser processing head 15 by a mounting bracket 19. And
The plasma removing nozzle 21 is mounted such that a shield gas G such as argon or nitrogen is directed to the plasma P from a surface of the plate W at a temperature of 40 to 60 degrees and is sprayed in a curtain shape. ..

Referring to FIGS. 2, 3 and 4, the plasma removing nozzle 21 is further provided with a gas passage 23 for supplying the shield gas G and at one end of the gas passage 23. The gas supply pipe 25 is screwed. A chamber 27 is formed in the plasma removing nozzle 21 at the other end of the gas passage 23.

Below the tip of the plasma removing nozzle 21, a lower plate 33 is provided with a plurality of screws 3 via a sealing member 31 made of rubber or the like having a substantially V-shaped groove 29.
It is attached by 5. The groove 29 formed in the seal member 31 communicates with the chamber 27. Since the seal member 31 having the substantially V-shaped groove 29 is interposed between the lower portion of the plasma removing nozzle 21 and the lower plate 33, as shown in FIG. A slit 37 is formed at the tip of the nozzle 21 by the thickness of the groove 27.

With the above structure, the shield gas G is supplied from the shield gas supply source (not shown), and the gas supply pipe 2
It is sent to the chamber 27 via 5. The shield gas G sent to the chamber 27 is ejected from the slit 37 to remove the plasma P generated during laser welding. The presence of the chamber 27 makes the shield gas G ejected from the slit 37 uniform.

The plasma P is removed by the shield gas G, and the surface of the heat-affected zone W _B formed around the fusion zone W _A is cooled by the shield gas G as shown in FIG. It is possible to eliminate the V-shaped welding and achieve uniform laser welding with an I-shaped welding surface with a narrow welding width.

The width of the slit 37 is L as shown in FIG. 4, and the width of the heat-affected zone WB is H as shown in FIG.
In such a case, if the width L of the slit 37 is increased so that H / L ≧ 2, the cooling effect is greatly enhanced, which is desirable. Further, the position for attaching the plasma removing nozzle 21 to the laser processing head 15 may be any position as long as it is an outer peripheral position adjacent to the laser processing head 15, but the laser processing head 15 is provided in front of the abutting portion in the welding direction. Is desirable.

The present invention is not limited to the above-described embodiment, but the slit 37 may have an elliptical shape or a shape in which a plurality of small holes are provided in series. It can be implemented in other modes by making appropriate changes.

[0026]

As will be understood from the above description of the embodiments, according to the present invention, since the structure is as described in the claims, plasma generated during laser welding is removed. It is possible to eliminate V-shaped welding and perform uniform laser welding with a narrow welding surface and an I-shaped welding surface.

[Brief description of drawings]

FIG. 1 is a schematic front view showing a main part of the present invention in which a plasma removal nozzle is attached to a laser processing head.

FIG. 2 is an exploded perspective view of a plasma removal nozzle.

FIG. 3 is a front sectional view of a plasma removal nozzle.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a schematic perspective view of a laser welding apparatus according to an embodiment of the present invention.

FIG. 6 is a welding state diagram of a plate material obtained by laser welding according to the present invention.

FIG. 7 is a welding state diagram of a plate material obtained by conventional laser welding.

[Explanation of symbols]

 1 Laser Welding Equipment 15 Laser Processing Head 17 Laser Nozzle 19 Mounting Hardware 21 Plasma Removing Nozzle 23 Gas Passage 27 Chamber 31 Sealing Member 33 Lower Plate 37 Slit

Claims (1)

[Claims] 1. A laser welding device for irradiating a laser beam from a laser processing head to a butt portion of a plate material and moving the laser processing head along a butt line in the butt portion to perform laser welding on the plate material. A plasma removal nozzle for removing plasma generated during laser welding is provided adjacent to the processing head, and a slit is formed so that the shield gas is directed toward the plasma at the tip opening portion of the plasma removal nozzle to spray in a curtain shape. A laser welding device, characterized in that it is formed into a shape.