JPH1147970A - Laser welding machine with automatic focusing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the quality of welding by automatically regulating a focal distance of a laser emitting part to a work through measuring of a distance between a welding point of the work and the laser emitting part with 3 range finder and detecting a devition between the measured distance and a focal distance of the laser emitting part. SOLUTION: A vertical frame member 6 is horizontally shifted by driving an electric motor 7 to coincide the range finder 9 with a welding point P of the work 2. At this position, by the range finder 9 making use of laser beam LB', the distance between a laser emitting part 1 and the welding point P is measured and operated by a controller. Then, a deviation between this distance and the focal distance of the laser emitting part 1 is operated by the controller. After that, by driving an electric motor 8, the laser emitting part 1 is vertically shifted so that the distance between the welding point P of the work 2 and the laser emitting part 1 coincide with the focal distance, and at the same time the electric motor 7 is again driven to shift the vertical frame member 6 horizontally.

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 with an automatic focusing mechanism capable of stabilizing welding quality.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
A laser welding apparatus for laser welding the works 2 and 2 with the laser beam LB emitted from the laser emitting unit 1 guided by the laser beam emitting unit 1 has been put to practical use.

[0003] The focal length X of the laser emitting section 1 of the laser welding apparatus as described above is determined by the fiber diameter and the magnification of the condenser lens, and is adjusted so that the laser emitting section 1 has an optimum focal length X. Thereby, the most efficient and stable laser welding can be performed.

In the conventional method of adjusting the focal length X, the distance between the work 2 and the laser emitting section 1 is visually measured on a scale 4 or is visually measured using a camera range finder. After that, the laser emission unit 1 is manually moved up and down while visually observing the scale 4.

In the case of laser welding, the focal length X has been adjusted while visually observing the minimum spot of a helium neon laser serving as guide light.

[0006]

However, in the conventional method, since the distance is measured visually and the adjustment is performed manually, not only is the measurement and adjustment work cumbersome and inaccurate, but also the first work is difficult. Measurement
After the adjustment work, the measurement and adjustment state was maintained, and the subsequent work was also laser-welded. If the work was warped or lifted, the focal length X fluctuated, and the welding quality (strength) was changed. ) Is apt to be unstable and unstable.

The present invention has been made to solve the above-mentioned conventional problems, and has as its object to provide a laser welding apparatus with an automatic focusing mechanism capable of stabilizing welding quality.

[0008]

In order to solve the above-mentioned problems, the present invention provides a laser welding apparatus for laser-welding a workpiece with a laser beam emitted from a laser emitting unit.
A distance meter is attached coaxially or adjacent to the laser emitting unit, and the distance between the welding point of the workpiece and the laser emitting unit is measured with the distance measuring device. The measured distance and the focal length of the laser emitting unit are measured. The present invention provides a laser welding device with an automatic focus adjustment mechanism, which is provided with a control device that detects a deviation of the laser beam and automatically adjusts a focal length of a laser emitting unit with respect to a workpiece.

According to the present invention, the distance between the welding point of the workpiece and the laser emitting section is automatically measured for each workpiece by the distance meter attached to the laser emitting section, and then the distance is measured by the control device. By detecting the difference between the distance and the focal length of the laser emitting unit, the focal length of the laser emitting unit at the welding point of the work is automatically adjusted for each work.

It is preferable that the automatic adjustment of the focal length of the laser emitting section is performed by an electric motor driven and controlled by the measured signal.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the same components and operations as those of the prior art are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIGS. 1 to 3, the laser welding apparatus is provided with a fixed horizontal frame member 5 and a vertical frame member 6 supported by the horizontal frame member 5 so as to be movable in the horizontal direction. Have been.

An electric motor 7 for horizontal driving is accommodated in the horizontal frame member 5, and the vertical frame member 6 is reciprocated in the horizontal direction H by the electric motor 7.

The vertical frame member 6 supports the laser emitting section 1 movably in the vertical direction. The laser emitting section 1 is moved in the vertical direction V by a vertical driving electric motor 8 housed in the vertical frame member 6. You will be reciprocated.

As shown in FIG. 3, a range finder 9 is integrally attached to the side of the laser emitting section 1 with a predetermined distance L therebetween. The range finder 9 is, for example, a laser displacement meter, and a laser beam LB 'emitted from the emission unit 9a.
The distance between the distance measuring instrument 9 and the welding point P of the work 2 is measured from the incident / emission angle when the light is reflected at the welding point P of the work 2 and enters the incident portion 9b. The range finder 9 may be a contact displacement meter.

Alternatively, the distance measuring device 9 may be coaxially attached to the laser emitting section 1 so that the constant distance L becomes 0 (zero). In this case, as described later, there is no need to drive the electric motor 7 to move the vertical frame member 6 horizontally by the distance L.

Since the vertical position of the range finder 9 and the laser emitting unit 1 are made to coincide with each other, the distance between the range finder 9 and the welding point P of the work 2 is changed. With the welding point P.

A control device 10 is attached to the laser welding device, and the control device 10 calculates a distance between the welding point P of the work 2 measured by the distance measuring device 9 and the laser emitting portion 1, The calculated distance and the laser emitting unit 1
Is calculated from the focal length X (for example, 30 mm), and the vertical drive electric motor 8 is driven by the vertical drive electric motor 8 so that the distance between the welding point P of the work 2 and the laser emitting unit 1 matches the focal length X. By outputting a signal, the focal length X of the laser emitting unit 1 is automatically adjusted.

The operation of the laser welding apparatus constructed as described above will now be described.

First, the electric motor 7 is driven to move the vertical frame member 6 horizontally, and the distance meter 9 is made to coincide with the welding point P of the work 2. At this position, as shown in FIG. The distance X 'between the laser emitting unit 1 and the welding point P is measured by the distance meter 9 using LB', and the control device 10 calculates the distance X '. This distance X '
Is 29 mm (or 31 mm), for example.

Next, the controller 10 calculates a deviation between the distance X 'and the focal length X (for example, 30 mm) of the laser emitting section 1. In this example, there is a shift of 1 mm in the minus direction (or a shift of 1 mm in the plus direction).

Thereafter, the electric motor 8 is driven to vertically move the laser emitting unit 1 so that the distance between the welding point P of the work 2 and the laser emitting unit 1 coincides with the focal length X. 7 is driven again to move the vertical frame member 6 horizontally by the distance L.

In this example, when there is a deviation of 1 mm in the minus direction, the laser emitting unit 1 is moved upward by 1 mm, and the distance between the welding point P of the work 2 and the laser emitting unit 1 is corrected to 30 mm. I do. Conversely, when there is a shift of 1 mm in the plus direction, the laser emitting unit 1 is moved downward by 1 mm.
mm, the distance between the welding point P of the work 2 and the laser emitting unit 1 is corrected to 30 mm.

Then, as shown in FIG. 2, a laser beam LB is emitted from the laser emitting section 1 to laser-weld the works 2 and 2.

According to the laser welding apparatus, the distance X 'between the welding point P of the work 2 and the laser emitting unit 1 is automatically measured for each work by the distance meter 9, and the measured distance X' and the laser emission The deviation from the focal length X of the unit 1 is calculated by the control device 10, and the electric motor 8 can automatically adjust the focal length X of the laser emitting unit 1 at the welding point P of the work 2 for each work.

Therefore, even if the workpiece 2 is warped or lifted, the focal length X of the laser emitting section 1 at the welding point P is automatically adjusted for each workpiece, so that the welding quality (strength) of the workpiece 2 is adjusted. Is stable, and the occurrence of defective welding is reduced.

Note that the measured distance X 'and the laser emission unit 1
When the deviation from the focal length X is too large, the controller 1
If it is determined that the workpiece 2 is abnormally warped or lifted at 0, the workpiece 2 is not laser-welded, thereby preventing the occurrence of defective welding.

[0028]

As is clear from the above description, the laser welding apparatus with the automatic focusing mechanism of the present invention uses the distance meter to measure the distance between the welding point of the work of the laser emitting section and the laser emitting section. Is automatically measured for each work, and the control device detects a deviation between the measured distance and the focal length of the laser emitting unit, and automatically adjusts the focal length of the laser emitting unit at the welding point of the work for each work. Therefore, even when the work is warped or lifted, the focal length of the laser emitting portion at the welding point is automatically adjusted for each work, so that the welding quality (strength) is improved. Becomes stable.

Further, since the distance between the welding point of the work and the laser emitting part is automatically measured and the focal length of the laser emitting part is automatically adjusted, the measuring and adjusting work can be performed easily and accurately. become.

[Brief description of the drawings]

FIG. 1 is a perspective view of a laser welding apparatus according to the present invention when measuring a distance.

FIG. 2 is a perspective view of the laser welding apparatus at the time of laser welding.

FIG. 3 is a system diagram of a laser welding apparatus.

FIG. 4 is a side view of a conventional laser welding apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser emission part 2 Work 5 Horizontal frame member 6 Vertical frame member 8 Electric motor 9 Distance finder 10 Controller LB Laser beam P Welding point X Focal length X 'Measurement distance

Claims (2)

[Claims] 1. A laser welding apparatus for laser-welding a workpiece with a laser beam emitted from a laser emitting section, wherein a distance measuring instrument is mounted coaxially or adjacent to the laser emitting section, and a welding point of the workpiece is measured by the distance measuring instrument. A control device that measures a distance between the laser emitting unit and the focal length of the laser emitting unit, detects a deviation between the measured distance and a focal length of the laser emitting unit, and automatically adjusts a focal length of the laser emitting unit with respect to the workpiece. A laser welding device with an automatic focusing mechanism. 2. The laser welding apparatus with an automatic focus adjusting mechanism according to claim 1, wherein the automatic adjustment of the focal length of the laser emitting unit is performed by an electric motor driven and controlled by the measured signal.