JPH06114581A - Laser beam welding machine - Google Patents

Abstract

PURPOSE:To obtain the laser beam welding machine capable of automatically meeting even a gap of the abutting surface meandering in the welding direction. CONSTITUTION:In the laser beam welding machine provided with a welding torch 1 to perform welding while moving along the abutting surface of materials 3 to be welded, an image pickup device 2 which is arranged ahead in the proceeding direction of the welding torch 1 and picks up an image of the gap G of the abutting surface, a picture processor 10 which analyzes an image of the gap G which is picked up on the image and operates the central position of the gap and a position controller 11 which controls a driving system 12 so that the central position of the welding torch 1 is made to the central position of the gap G according to a signal of the picture processor 10 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser welding machine for automatically welding along a butt surface of a member to be welded.

[0002]

2. Description of the Related Art A laser welding machine using a laser beam such as a carbon dioxide gas laser, a YAG laser, and a ruby laser as a heat source is far superior in converging property to ordinary light and has a high energy density of about 1000 times the arc heat. It can collect light. Therefore, it is often used in the field of precision welding. In order to make full use of the characteristics of such a laser welder,
It is necessary to accurately irradiate the abutting surface with the laser beam, and it is generally necessary to suppress the error within 0.1 to 0.3 mm.

Therefore, various laser beam alignment techniques have been proposed in the past.

[0004] The most common method is a method in which a member to be welded is butted against a gap of zero after shirring, and the butted surface is irradiated with a low-power laser beam for visual confirmation. This method is the most reliable method, but it varies depending on the accuracy of shirring, and it is necessary to periodically check the zero point.

Further, in Japanese Patent Publication No. 4-33555, a reference groove is installed on a reference plate installed off-line, and the positional deviation between the center line of the reference groove and the butt center line of the metal strip is zero. , A laser welding machine for controlling the position of the welding torch in the line direction is disclosed.

According to this apparatus, it is possible to automatically eliminate the positional deviation between the butt center line and the welding center line, and to maintain stable welding strength.

[0007]

However, the laser welding machine disclosed in Japanese Examined Patent Publication No. 4-33555 has a zero point position fixed because the zero point position is confirmed by a reference plate provided off-line. However, it is not possible to deal with the case where the gap changes in the plate width direction.

[0008] The problem to be solved by the present invention is to obtain a laser welding machine which can automatically cope with the case where the gap between the abutting surfaces meanders in the welding direction.

[0009]

In order to solve the above-mentioned problems, the present invention provides a laser welding machine equipped with a welding torch for welding while moving along a butt surface of a material to be welded, in a traveling direction of the welding torch. An image pickup device for picking up a gap on the abutting surface arranged in front, an image processing device for analyzing a picked up image of the gap to calculate a gap center position, and a center position of the welding torch by a signal from the image processing device. And a position control device that controls the drive system so that the position becomes the center position of the gap.

Here, a light source for irradiating the gap of the abutting surface is provided on the side of the member to be welded opposite to the image pickup device, or a spatter adhesion preventing slider that moves in conjunction with the welding torch and covers the front surface of the light source is provided. You can

[0011]

In the present invention, the welding position is preliminarily imaged by the imaging device, and the center position of the welding torch is feedforward-controlled based on this information, so that the center position of the welding torch can be reliably positioned at the butt center. Also, by illuminating the gap from the side opposite to the imaging device,
Accurate imaging of the gap becomes possible without being affected by diffused reflection of the material to be welded. Furthermore, by providing a slider for preventing spatter adhesion, the light quantity of the light source can be maintained for a long time.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a structural view showing a use mode of a laser welding machine according to an embodiment of the present invention, and FIG. 2 is a side sectional view of the same.

1 is a welding torch which moves along the welding surface,
Reference numeral 2 denotes a light receiving sensor as an image pickup device arranged at a front position in the traveling direction of the welding torch 1. A steel plate 3 as a member to be welded is fixed by an upper clamp 4 and a lower clamp 5, and a back bar 6 having an open upper surface is arranged on the lower surface of the steel plate 3. Inside the back bar 6, a light source 7 for irradiating the gap G of the abutting surface is provided over the entire width. 8
Is a slider which is located immediately below the welding torch 1 and covers the front surface of the light source 7, and which has a width reaching up to the front of the light source 7 about the axis of the welding torch 1 and moves in conjunction with the welding torch 1. Reference numeral 9 is a filler wire for automatically supplying the filler material to the welded portion. Further, the light receiving sensor 2 is connected to an image processing device 10 which binarizes and analyzes the captured image of the gap G and calculates the gap center position. Further, the center position of the welding torch 1 is received by a signal from the image processing device 10. A position control device 11 for controlling the stepping motor 12 is provided so that is at the center position of the gap G.

Next, the operation of the laser welding machine during welding will be described with reference to the flowchart of FIG.

With the start of the welding operation, the welding torch 1 is moved along the butt surface by a driving device (not shown), and welding is automatically performed while supplying the filler wire 9. At this time, the light receiving sensor 2 preceding the welding torch 1 images the gap G of the abutting surface, and the image processing apparatus 10 calculates the center position of the gap G. The position control device 11 is activated by this signal to drive the stepping motor 12. As a result, the welding torch 1 moves in the direction (X-axis direction) perpendicular to the welding line, and the center position of the welding torch 1 is controlled to be the center position of the gap G. At this time, assuming that the distance between the light receiving sensor 2 and the welding torch 1 is L and the laser feed speed is Y, the welding torch 1 is reached after t = L / Y time.
Is controlled to be the center position of the gap G. This operation is continuously performed over the entire welding line.

As described above, according to the laser welding machine of the present embodiment, the welding torch 1 follows this even when the butt surface is meandering, so that the center position of the gap G can always be accurately irradiated. become. Further, since the light source 7 is arranged on the back side of the steel plate 3 which is the material to be welded 4, that is, on the side opposite to the light receiving sensor 2 and detects the light leaked from the gap G, the light is scattered on the surface of the steel plate 3. Detection error can be prevented. Further, since the slider 8 for preventing spatter adhesion is provided on the front surface of the light source 7, it is possible to prevent spatter from adhering to the light source 7 and always secure the light amount of the light source.

[0017]

According to the present invention, the following effects can be obtained.

(1) Since the center position of the gap is detected by the preceding image pickup device and the center position of the laser beam is continuously controlled by this, the laser is always positioned at the center position of the gap even on the meandering butt surface. The beam can be emitted.

(2) By disposing the light source on the side opposite to the image pickup device, it is possible to eliminate a detection error due to scattering on the surface of the member to be welded.

(3) The light quantity of the light source can be maintained by providing the slider for preventing spatter adhesion.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a laser welding machine that is an embodiment of the present invention.

FIG. 2 is a side sectional view of the laser welding machine shown in FIG.

FIG. 3 is a flowchart of position control of a welding torch.

[Explanation of symbols]

 1 Welding torch 2 Light receiving sensor (imaging device) 3 Steel plate (material to be welded) 4 Upper clamp 5 Lower clamp 6 Back bar 7 Light source 8 Slider 9 Filler wire 10 Image processing device 11 Position control device 12 Stepping motor (driving system)

Claims (3)

[Claims] 1. A laser welding machine provided with a welding torch for welding while moving along a butt surface of a material to be welded,
An image pickup device for picking up an image of the gap of the abutting surface arranged in the forward direction of the welding torch, an image processing device for analyzing the image of the taken gap to calculate the gap center position, and a signal of the image processing device. A laser welding machine, comprising: a position control device that controls a drive system so that the center position of the welding torch becomes the center position of the gap. 2. The laser welding machine according to claim 1, further comprising a light source for irradiating a gap of a butting surface on a side of the member to be welded which is opposite to the imaging device. 3. The laser welding machine according to claim 2, further comprising a slider for preventing spatter adhesion that moves in association with the welding torch and covers the front surface of the light source.