JPH05131282A - Method and device for laser beam welding - Google Patents

Abstract

PURPOSE:To obtain the welding surface of less defect at the molten part by pressing the butt surface and welding while scanning the laser beam. CONSTITUTION:The metal plate W is kept in the state that the butt welding line P is pressed with an elastic belt 25 being tucked up in crossing with rollers composed of two stages of upper and lower 19A, 19B, 21A, 21B. The laser beam of laser beam welding machine 1 are refract with X axis mirror in a machining head 3 and becames to the lasers beam with a collecting lens. Y axis mirror 13 composing a polariscope A scans on the straight line, and the focus is moved and compensated with Z axis scanner set on the collecting lens 11. A swelled weld zone is finished with grinding and the weld zone of the plate thickness as same as the base material can be obtained without blow- hole or undercut.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser welding method and apparatus for performing laser welding on an abutting surface of a work such as a band saw blade.

[0002]

2. Description of the Related Art Conventionally, laser welding, which is performed by melting a base metal using a high-power laser, has a narrow bead width and deep penetration, and since the heat-affected layer is thin, the mechanical strength of the weld is high. It has been used extensively.

To weld a band saw blade, which is formed in a loop shape, for example, using this laser light, both ends of the band saw blade are used as butt faces, and the butt faces are used as welding lines and fixed to the bed portion of the laser welding machine. A laser processing head is arranged above the welding line, and the laser processing head is moved along the welding line or the bed portion is moved to perform laser welding.

[0004]

However, in the above-mentioned conventional laser welding, since the base material of the band saw blade is melted and welded, a part of the base material is penetrated and the thickness of the welding beam portion is different from that of the base material. There is a risk that the thickness decreases and undercut occurs, and the strength of the base material is insufficient and the saw blade is cut during the work.

In addition, running the laser processing head along the welding line or moving the bed portion depends on the maximum speed of the mechanical system and the acceleration / deceleration time, and the welding start point and end point. It was difficult to obtain a weld bead that would make the entire area of the welded part of the material uniform due to dents and heat effects.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bead having a raised molten portion on the front surface and the back surface of a material, and to reduce blowout defects such as blowholes. (EN) A laser welding method and apparatus capable of obtaining a welded surface and, after polishing to a flat surface, a flat surface having the same plate thickness as the base material and no undercut.

[0007]

In order to achieve the above object, the laser welding method of the present invention is such that, when welding a workpiece with a laser beam, the abutting surface is pressed against the abutting surface of the workpiece. It is characterized in that laser welding is performed on.

Further, in the laser welding apparatus of the present invention, a laser beam is applied to the pressing device for pressing the abutting surface of one work and the other work, and the welding line on the abutting surface pressed by the pressing device. A laser processing head having a polarizer for high-speed scanning, or a laser processing head having a polarizer for linearly irradiating the welding line with the laser beam is provided.

[0009]

The laser welding method and apparatus having the above-mentioned structure are
Laser light is irradiated so that the abutting surfaces of one work and the other work are intimately pressed against each other, and a bead that is always raised in the molten portion can be obtained. This raised bead can be finished by polishing to the same plate thickness as the base material.

In addition, since the laser beam uses a laser processing head having a polarizer, uniform welding can be performed without being influenced by the mechanical system unlike movement of the mechanical system.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, a laser welding head 1 is provided at an upper portion of the laser welding machine 1 and is composed of a rectangular cylindrical housing vertically provided from above. A head housing 5 is provided so as to project to the inside. The head housing 5 is also formed in a hollow shape, and is squeezed downward from the left and right sides with an inclined portion at the lower portion of the head housing 5, and the lower end surface is provided with an opening.

An X-axis mirror 7 for refracting the laser is provided inside the laser processing head 3 in the direction in which the head housing 5 is provided, and the X-axis mirror 7 is provided.
Are provided so that they can be finely adjusted via an X-axis scanner motor 9.

On the optical axis of the laser light refracted by the X-axis mirror 7, a condenser lens 11 is provided with a focus correction mechanism (not shown) and a Z-axis scanner motor. Inside the head housing 5 in front of the condenser lens 11, the Y-axis mirror 13 for refracting the laser light condensed by the condenser lens 11 in the right angle direction and irradiating the laser light downward from the opening. Is provided.

A supporting shaft 15 for rotating the Y-axis mirror 13 is provided at the center of the Y-axis mirror 13. This spindle 1
5 has a Y-axis scanner motor 17 attached,
A polarizer A for rotating the Y-axis mirror 13 to linearly scan the laser light downward is formed.

The welding laser light of the laser welding machine 1 is irradiated with laser light from a laser oscillator (not shown) on the X-axis mirror 7 in the laser processing head 3, and is refracted by the X-axis mirror 7 to be collected. The light is condensed by the optical lens 11 to form a laser beam, which is then scanned by the Y-axis mirror 13 forming the polarizer A to travel on a straight line. The Z-axis scanner motor provided in the condenser lens 11 corrects the movement of the focus accompanying the scanning in the Y-axis direction, and the focus of the laser beam light is always accurately formed over a predetermined width. It is like this.

A plate material W to be a work is arranged on the scanning surface which focuses on the predetermined width. The plate material W has a predetermined thickness and width. Needless to say, the thickness direction is restricted by the intensity of the laser beam and the width direction is restricted by the focus range of the condenser lens 11. By the way.

The plate material W is supported by a pressing device 23 having rollers 19A and 19B and upper and lower two stages 19A and 21B, respectively, on the right and left sides of the butt welding line P in line with the scanning line. .. The rollers 19A and 19B and the roller 21 of the pressing device 23
A belt 25 made of an elastic material is provided on each of A and 21B so that the upper and lower rollers 19A and 19B;
Both A and 21B are drawn inward and rotated in opposite directions. Therefore, the plate material W sandwiched between the upper and lower rollers 19A and 19B and the rollers 21A and 22B is sent so as to be pushed into, for example, the side between the rollers 19A and 21A, and is sandwiched and pushed from the left and right respectively. The abutting surfaces of the plate members W are supported in a state of being joined at the intermediate portion (position of the scanning line). By irradiating and scanning the abutting surface with the laser beam, the abutting surface of the plate material W is welded in a state of being pressed from the left and right sides, so that the molten portion has a raised beat B as shown in FIG.
And a welded surface without blowholes.

Therefore, by polishing the welded surface to be flat with a grinder or the like, the welded surface can be formed without damaging the plate thickness of the plate material W and without undercut at both ends.

FIG. 3 shows an example of the control device of the laser welding machine 1 described above. In FIG. 3, the Y-axis scanner motor 17 that rotates the Y-axis mirror 13 that scans the laser beam emitted to the plate material W is connected to the Y-axis servo amplifier 27. Further, the X-axis scanner motor 9 for adjusting the X-axis mirror 7 includes an X-axis servo amplifier 2
A Z-axis servo amplifier 33 is connected to a Z-axis scanner motor 31 that adjusts the condenser lens 11 serving as the Z-axis. Each of these servo amplifiers 27, 29, 33 is connected to the computer 39 through the interface 35, one through the digital generator 37, and the other is directly connected to the computer 39. A line from the interface 35 is connected to the laser oscillator 41, and all of these controls are performed by the computer 39. Information is input to the computer 39 via the keyboard 43.

The laser welding machine 1 described above scans the laser beam light by the polarizer A by rotating the Y-axis mirror 13. By vibrating the Y-axis mirror 13, the laser beam light is vibrated. The same effect can be obtained as a polarizer used as.

In addition to the above-mentioned polarizers, there is an acousto-optic polarizer. This acousto-optic polarizer B uses a black diffraction phenomenon in a diffraction grating generated in an ultrasonic medium, and irradiates the ultrasonic medium with a laser beam light from a predetermined angle, while the ultrasonic medium is supersonic. By inputting the frequency of the sound wave in a sawtooth shape, the laser beam light has a cylindrical lens effect of diffracting only in the direction parallel to the propagation direction of the ultrasonic wave. By arranging a cylindrical lens equivalent to this cylindrical lens effect, the laser beam light is scanned.

The laser welding machine using the various polarizers described above is of a type capable of high-speed scanning, unlike scanning by the traveling of the laser processing head or the traveling of the bed portion by a mechanical system. A laser processing head of a scanning system using these polarizers is provided, a butting surface (welding line P) of a plate material W is installed on the scanning line, and the left and right plate materials to be butted are rollers 19A and 19B shown in FIG. 21A
It is possible to form the bead B having the raised melting portion shown in FIG.

The present invention is not limited to the above-mentioned embodiment, but by performing appropriate polarization,
It can be implemented in other modes.

[0025]

As described above, according to the present invention,
Since the configuration is as described in the claims,
There is an advantage that the laser beam of the laser welding machine scans up the welding bead portion of the plate material and pushes out the blowholes or the like without impairing the strength of the base material to obtain a welding surface with few melting defects.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a laser welding machine according to an embodiment of the present invention.

FIG. 2 is a plan view of a processed product produced by the laser welding machine shown in FIG.

3 is a configuration block diagram of a control device in the laser welding machine of FIG. 1. FIG.

[Explanation of symbols]

 1 Laser Welding Machine 5 Head Housing 23 Pressing Device A Polarizer

Claims (3)

[Claims] 1. When welding a work with a laser beam, while pressing the work against the butt surface of the work,
A laser welding method, characterized in that laser welding is performed on the butt surfaces. 2. Laser processing having a pressing device for pressing the abutting surface of one work and the other work, and a polarizer for scanning the laser beam at a high speed on the welding line on the abutting surface pressed by the pressing device. A laser welding device comprising: a head. 3. A polarizer for linearly irradiating a laser beam on a pressing device for pressing an abutting surface of one work and the other work, and a welding line on the abutting surface pressed by the pressing device. And a laser processing head having a laser welding head.