JPH07214354A - Method and device for synthesizing laser beam and for laser beam welding - Google Patents

Abstract

PURPOSE:To improve the welding performance by increasing the focal depth of the whole synthesized laser beam where a plurality of laser beams are synthesized. CONSTITUTION:When two laser beams 1, 4 oscillated from two laser beam oscillators are crossed and synthesized, and two laser beams 1, 4 are converged to the respective points by two converging lens 2, 5, two converging points 3, 6 are arranged on the line along the direction of the respective optical axes 1a, 4a of two laser beams 1, 4, and in a slightly deviated manner. This constitution allows the range suitable for two kinds of welding to be also deviated because the slight deviation of two converging points 3, 6 even when the focal depth of the respective laser beams 1, 4, i.e., the range suitable for the welding may be the range of the same degree as that of the conventional one, and the focal depth of two laser beams 1, 4 as the whole is fairly increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam synthesizing method and apparatus for synthesizing two or more laser beams by crossing them, and a laser welding method and apparatus for welding using the synthesized laser beams.

[0002]

2. Description of the Related Art Of the laser light, CO2 laser light, for example, has a high energy density and is used for welding. Specifically, when the laser light is condensed by a condensing lens, the laser light becomes a heat source with a high power density near the condensing point, and by adjusting the distance between the condensing point and the material to be welded, The desired welding performance is obtained. In this case, when the material to be welded is separated from the converging point, the power density of the laser beam applied to the material to be welded is lowered and the welding performance is reduced. The range where good welding performance is obtained is called the depth of focus. It is known that the higher the power density at the converging point, the easier it is to melt the material to be welded, and the deeper (longer) the focal depth is, the deeper the penetration depth is.

[0003]

However, in the above-mentioned conventional structure, the depth of focus as the welding performance of laser welding is not so deep, and there is a drawback in that welding with a deep penetration depth cannot be performed. .

On the other hand, as a method of increasing the power intensity of the laser beam at the converging point, it is conceivable to increase the output of the laser beam itself. However, since the rated output of the laser oscillator is fixed, The output cannot be higher than the rated output of the laser oscillator. Therefore, by using a plurality of laser oscillators, a plurality of laser beams oscillated from each laser oscillator are respectively focused, and each focusing point is made to coincide with one focusing point. Conventionally, a method of increasing the power intensity at one focus point has been considered.

However, in the case of the above method, although the power intensity at the converging point is high, the method is such that a plurality of laser beams are used because the condensing points of a plurality of laser beams are made to coincide with each other. The depth of focus of the laser light as a whole is
It was almost the same as the depth of focus of one laser beam, and was not so deep. Therefore, an object of the present invention is to provide a laser beam synthesizing method and a device thereof and a laser welding method and a device thereof capable of increasing the depth of focus.

[0006]

A laser beam synthesizing method according to the present invention is a laser beam synthesizing method in which two laser beams oscillated from two laser oscillators are crossed and combined with each other. When converging at one point, the two converging points are arranged on a straight line substantially along each optical axis direction of the two laser beams, and are also slightly shifted. In this case, for at least one laser beam of the two laser beams, an adjustment optical system for adjusting a focal point is provided in front of the focusing optical system, so that the distance between the two focal points is increased. Is also preferably adjusted.

Further, in a laser beam synthesizing method for intersecting and synthesizing three or more laser beams oscillated from three or more laser oscillators, each optical axis of the three or more laser beams is in one plane. And place the 3
When concentrating each of the three or more laser beams at one point, the three or more condensing points are arranged on a straight line substantially along each optical axis direction of the three or more laser beams, and are also slightly displaced from each other. It is also possible to do so. In this case, the above 3
Adjusting the distance between the three or more converging points by providing an adjusting optical system for converging point adjustment on the front side of the converging optical system for at least one laser beam among the plurality of laser beams. It may be done.

Further, in the laser welding method in which the laser light synthesized by the above-mentioned laser light synthesizing methods is used for welding, the direction of the welding is generally with respect to the plane formed by the optical axes of the plurality of laser lights. It is an even more preferable method to set the directions in parallel.

Further, the laser beam synthesizing apparatus of the present invention is an apparatus for crossing and synthesizing two laser beams oscillated from two laser oscillators, and when the two laser beams are respectively focused on one point. In addition, the two converging points are arranged on a straight line substantially along each optical axis direction of the two laser beams, and the condensing means for arranging them slightly apart is provided. In the case of this configuration, for at least one laser beam of the two laser beams, an adjusting optical system for adjusting the distance between the two focusing points is provided in front of the focusing optical system. Preferably.

Further, in a laser beam synthesizing apparatus for synthesizing three or more laser beams oscillated from three or more laser oscillators by crossing them, each optical axis of the three or more laser beams is in substantially one plane. When the three or more laser lights are focused on one point, the three or more focus points are straight lines substantially along the optical axis directions of the three or more laser lights. It is even more preferable to have a configuration in which the light collecting means is arranged on the upper side and is displaced slightly. In the case of this configuration, an adjusting optical system for adjusting the distance between the three or more condensing points is provided in front of the condensing optical system for at least one of the three or more laser beams. However, this is also a preferable configuration.

Then, in the laser welding apparatus for welding using the laser beams synthesized by the above laser beam synthesizing apparatuses, the welding direction is generally with respect to the plane formed by the optical axes of a plurality of laser beams. It is an even more preferable apparatus that includes a movement driving unit that moves and drives the laser light or the object to be welded so as to be parallel.

[0012]

According to the above means, when the two laser beams are focused on one point, the two focusing points are arranged on a straight line substantially along each optical axis direction of the two laser beams. Since they are arranged so as to be slightly shifted, even if the focal depth of each laser beam, that is, the range suitable for welding is the same range as the conventional range, the two focal points are slightly displaced. Therefore, the range suitable for the above two weldings also deviates, and the depth of focus of the two laser beams as a whole widens considerably. Therefore, the depth of focus can be increased as compared with the conventional configuration. In this case, specifically, for at least one of the two laser beams, by providing an adjusting optical system for adjusting the focusing point on the front side of the focusing optical system, two focusing points can be obtained. It is possible to adjust the distance between them to be slightly deviated.

Further, in a laser beam synthesizing method for crossing and synthesizing three or more laser beams oscillated from three or more laser oscillators, the respective optical axes of the three or more laser beams are arranged in substantially one plane. When concentrating three or more laser lights at one point, three or more condensing points are arranged on a straight line substantially along each optical axis direction of the three or more laser lights. At the same time, the positions are slightly shifted so that the depth of focus can be further increased.
Also in this case, for at least one of the three or more laser beams, by providing an adjusting optical system for adjusting the focal point on the front side of the focusing optical system, three or more laser beams are focused. It is possible to adjust the distance.

On the other hand, in the laser welding method in which the laser beams synthesized by the above laser beam synthesizing methods are used for welding, the welding direction is generally with respect to the plane formed by the optical axes of the plurality of laser beams. Since the directions are set to be parallel to each other, the weld penetration shape produced in the material to be welded by the laser welding becomes linear and the welding quality is improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. In FIG. 1, a first laser beam 1 oscillated and output from a first laser oscillator is condensed by a condensing optical system, for example, a first condensing lens 2 to form a first condensing point 3. Configured to form. The second laser light 4 oscillated and output from the second laser oscillator is, for example, a second condenser lens 5 which is a condenser optical system.
Is formed to form the second condensing point 6. The two laser beams 1 and 4 are set so that the optical axes 1a and 4a intersect at a shallow angle. Here, the two condensing points 3 and 6 are almost (generally) almost in the respective optical axes 1a and 4a of the two laser beams 1 and 4.
They are arranged in series on a straight line along them, and are arranged with a slight shift in the vertical direction in FIG. In this case, the distance (deviation amount) between the two condensing points 3 and 6 is, for example, several mm.
It is set to about (5 mm at maximum).

The two condenser lenses 2 and 5 are provided so as to be capable of reciprocating along the directions of the optical axes 1a and 4a, respectively. In this case, the distance between the two condensing points 3 and 6 can be set to a desired distance by moving the two condensing lenses 2 and 5. This makes it possible to deal with actual (various) welding conditions when performing laser welding with the apparatus having the above configuration. In this case, the two condenser lenses 2 and 5 constitute a condenser means.

However, according to the above configuration, when considering the case of laser welding with only the first laser beam 1, the range suitable for welding (referred to as the first range) is as shown in FIG. The area A is before and after the first condensing point 3. The first range A is the depth of focus of the first laser light 1. In this range A, the energy density (power density) is about 90% or more of the energy density at the converging point 3. On the other hand, considering a case where laser welding is performed only by the second laser beam 4, the range suitable for welding (referred to as the second range) is, as shown in FIG. It becomes the area B. This second range B is the second laser beam 4
Depth of focus.

Here, since the two converging points 3 and 6 are slightly deviated in the vertical direction in the drawing, the ranges A and B suitable for welding are also deviated with a slight overlap. Therefore, 2
When laser welding is performed using the laser beams 1 and 4 of the book, the range suitable for welding is a range in which the first range A and the second range B are almost added, and the focal depth as a whole is the range A.
And a range B are added to extend to a region almost close to the range. Therefore, in this embodiment, the power density (energy density) can be made uniform and the depth of focus can be made deeper than in the conventional configuration. As a result, since welding having a deep penetration depth can be performed, a laser welding bead having a deep penetration depth can be obtained, and welding performance is significantly improved. For this reason, in the above-described embodiment, it is possible to weld an object to be welded having a plate thickness that could not be welded only by scanning once, by only scanning once, and the laser welding speed is improved. It is significantly higher and the total welding work time can be reduced.

When laser welding is performed in the above embodiment, as shown in FIG. 1, the first laser beam 1 and the second laser beam 4 intersect with each other at an intersection angle K (the optical axis 1a and the optical axis 4a are different from each other). Since they intersect so as to form an angle), the range suitable for welding the combined light of the two laser beams 1 and 4 is the range obtained by adding the first range A and the second range B, that is, It is a range that is bent in an almost "U" shape. In this case, the welding direction is 2
If the direction is set to intersect with the plane formed by the optical axes 1a and 4a of the laser beams 1 and 4 of the book, the range suitable for welding the combined light of the two laser beams 1 and 4 is almost " Ku "
Since it is bent in a letter shape, the weld-melting shape generated in the material to be welded by the laser welding is bent, and the quality of welding may be deteriorated.

On the other hand, in the above-described embodiment, the welding direction P when performing laser welding is set to 2 as shown in FIG.
The configuration is such that the laser beams 1 and 4 of the book are set to be substantially parallel to the plane formed by the optical axes 1a and 4a. Specifically, there is provided a moving drive means for moving and driving the two laser beams 1 and 4 in the P direction, or a moving drive means for moving and driving the welded body in the P direction. As a result, even if the range suitable for welding by the combined light of the two laser beams 1 and 4 is bent in a substantially V shape, the weld penetration shape generated in the welding material is linear, so that the quality of welding is improved. Can be improved.

In the above embodiment, the two condensing lenses 2 and 5 are provided so as to be reciprocally movable in the directions of the optical axes 1a and 4a, but the present invention is not limited to this, and the two condensing lenses are two. Similar effects can be obtained even if only one of 2, 5 is provided so as to be reciprocally movable.

FIG. 2 shows a second embodiment of the present invention, and the difference from the first embodiment will be described. still,
The same parts as those in the first embodiment are designated by the same reference numerals. In the second embodiment, as shown in FIG. 2, on the front side of each of the first condenser lens 2 and the second condenser lens 5, for example, a first adjustment lens is provided as an adjustment optical system for adjusting the focal point. 7 and a second adjusting lens 8 are provided. These first adjustment lenses 7
The second adjusting lens 8 is provided so as to be capable of reciprocating in the directions of the optical axes 1a and 4a, respectively. In this case, the distance between the two condensing points 3 and 6 can be set to a desired distance by moving the two adjusting lenses 7 and 8. In the case of this configuration, the two focusing lenses 2 and 5 and the two adjusting lenses 7 and 8 constitute the focusing means. The configuration other than the above is the same as the configuration of the first embodiment. Therefore, also in the second embodiment described above, it is possible to obtain substantially the same operational effects as in the first embodiment.

In the second embodiment, the two adjusting lenses 7 and 8 are configured to be movable, but the present invention is not limited to this, and only one of the two adjusting lenses can be moved. It may be configured to. Further, in the second embodiment, the two laser beams 1 and 4 are condensed by the two condenser lenses 2 and 5, but instead of this, the two laser beams 1 and 4 are condensed. The configuration may be such that the light is condensed by two condenser lenses. Also in this configuration, the two adjusting lenses 7 and 8
By moving the, the distance between the two condensing points 3 and 6 can be set to a desired distance.

In each of the above embodiments, the case where the two laser beams 1 and 4 oscillated from the two laser oscillators are crossed and combined is applied, but the present invention is not limited to this. The present invention may be applied to a case where three or more laser beams oscillated and output from laser oscillators on a table or more are crossed and combined. In this case, in the method of intersecting and synthesizing three or more laser beams, it is preferable that the optical axes of the three or more laser beams are arranged in substantially one plane. When converging three or more laser lights at one point, three or more converging points are arranged on a straight line substantially along each optical axis direction of the three or more laser lights and slightly shifted. It may be configured to be arranged. With this configuration, the depth of focus can be further increased. Further, it is even more preferable to set the welding direction in the case of performing laser welding so as to be substantially parallel to one plane formed by the optical axes of three or more laser beams. By setting the welding direction in this way, even if the range suitable for welding by the combined light of three or more laser beams is curved, the weld penetration shape generated in the welding material becomes linear, so that the quality of welding is improved. be able to.

Further, for at least one laser beam among the three or more laser beams, an adjusting lens is provided as an adjusting optical system for adjusting the focusing point in front of the focusing lens (focusing optical system). It is also a preferable configuration. With this configuration, it is possible to freely adjust the distance between the three or more converging points.

In each of the above embodiments, the condensing optical system and the adjusting optical system are constituted by the transmitting optical system including the condensing lens and the adjusting lens, but the present invention is not limited to this.
It may be configured by a reflection optical system including a reflection mirror that reflects laser light.

[0027]

As is apparent from the above description, the present invention is effective in converging two laser beams at one point.
Since the two converging points are arranged on a straight line substantially along each optical axis direction of the two laser beams and are arranged with a slight offset, the focal depth of the two laser beams as a whole is deepened. Can improve the welding performance,
As a result, there is an excellent effect that the working time required for welding can be shortened. In this case, for at least one of the two laser beams, an adjusting optical system for adjusting the focal point is provided on the front side of the focusing optical system to slightly reduce the distance between the two focal points. It is possible to adjust so as to shift.

In addition, in a laser beam synthesizing method (or apparatus) for intersecting and synthesizing three or more laser beams oscillated from three or more laser oscillators, each optical axis of the three or more laser beams is almost one. When arranging in a plane, and converging three or more laser lights at one point, three or more condensing points are straight lines substantially along each optical axis direction of the three or more laser lights. Since it is arranged on the upper side and slightly displaced, the depth of focus can be further increased. Also in this case, for at least one of the three or more laser beams, by providing an adjusting optical system for adjusting the focal point on the front side of the focusing optical system, three or more laser beams are focused. It is possible to adjust the distance.

On the other hand, in the laser welding method in which the laser beams synthesized by the above laser beam synthesizing methods are used for welding, the welding direction is generally with respect to the plane formed by the optical axes of the plurality of laser beams. Since the directions are set to be parallel to each other, the weld-melting shape generated in the material to be welded by the laser welding becomes linear, and the quality of welding can be improved.

[Brief description of drawings]

FIG. 1 is a schematic side view of a laser beam synthesizing apparatus showing a first embodiment of the present invention.

FIG. 2 is a schematic side view of a laser beam synthesizing apparatus showing a second embodiment of the present invention.

[Explanation of symbols]

1 is a first laser beam, 1a is an optical axis, 2 is a first condenser lens (condensing optical system), 3 is a first focusing point, 4 is a second laser beam, 4a is an optical axis, Reference numeral 5 is a second condenser lens (condensing optical system), 6 is a second condenser point, 7 is a first adjusting lens (adjusting optical system), and 8 is a second adjusting lens (adjusting optical system). Show.

Claims (10)

[Claims] 1. A laser beam synthesizing method for crossing and synthesizing two laser beams oscillated from two laser oscillators, wherein each of the two laser beams is focused on one point,
2. A laser beam synthesizing method characterized in that two converging points are arranged on a straight line substantially along each optical axis direction of the two laser beams and are arranged with a slight offset. 2. An adjusting optical system for adjusting a condensing point is provided in front of the condensing optical system for at least one laser beam of the two laser beams so that a distance between the two condensing points is increased. 2. The laser beam synthesizing method according to claim 1, wherein the distance is adjusted. 3. A laser beam synthesizing method for crossing and synthesizing three or more laser beams oscillated from three or more laser oscillators, wherein each optical axis of the three or more laser beams is in one plane. When the three or more laser lights are focused on one point, three or more focus points are arranged on a straight line substantially along each optical axis direction of the three or more laser lights. And place it in
A laser beam synthesizing method characterized by arranging them with a slight shift. 4. At least one laser beam of the three or more laser beams is provided with an adjusting optical system for adjusting a focusing point in front of the focusing optical system, so that the three or more laser beams are collected. The laser beam synthesizing method according to claim 3, wherein the distance between the light spots is adjusted. 5. A laser welding method for welding using laser light synthesized by the laser light synthesizing method according to any one of claims 1 to 4, wherein the welding direction is a plurality of optical axes of the laser light. The laser welding method is characterized in that the direction is substantially parallel to the plane formed by. 6. A laser beam synthesizing device for crossing and synthesizing two laser beams oscillated from two laser oscillators, wherein each of the two laser beams is focused at one point.
2. A laser beam synthesizing device, comprising: two condensing points arranged on a straight line substantially along each optical axis direction of the two laser beams, and further comprising condensing means arranged so as to be slightly displaced from each other. 7. An adjusting optical system for adjusting a distance between the two condensing points is provided in front of the condensing optical system for at least one of the two laser beams. The laser light synthesizing apparatus according to claim 6, which is characterized in that. 8. A laser beam synthesizing device for crossing and synthesizing three or more laser beams oscillated from three or more laser oscillators, wherein each optical axis of the three or more laser beams is in substantially one plane. When the three or more laser beams are focused on one point, the three or more focusing points are straight lines substantially along the optical axis directions of the three or more laser beams. A laser beam synthesizing device comprising a condensing unit arranged on the upper side and slightly displaced. 9. An adjusting optical system for adjusting the distance between the three or more converging points is provided in front of the condensing optical system for at least one of the three or more laser beams. 9. The laser beam synthesizing device according to claim 8, wherein 10. A laser welding apparatus for welding using laser light synthesized by the laser light synthesizing apparatus according to any one of claims 6 to 9, wherein the welding direction is a plurality of optical axes of the laser light. 2. A laser welding apparatus, comprising: a movement driving unit that moves and drives the laser light or the object to be welded so as to be substantially parallel to the plane formed by.