JP2885026B2 - Laser beam welding method and laser beam welding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding method and a welding apparatus for laser beam welding in which both ends of a preceding workpiece and a following workpiece are butt-welded.

[0002]

2. Description of the Related Art FIG. 10 and FIG.
It is a perspective view showing the composition of the conventional laser beam welding device shown in -200986 gazette. In the figure, 1 is a common base, 2 and 3 are front and rear clamping devices provided at predetermined intervals on the common base 1 at front and rear, and 4 is between the front clamping device 2 and the rear clamping device 3. Is a back bar device which can move back and forth between the front clamp device 2 and the rear clamp device 3 from the left and right direction, like the shear device 4.
Is an upper head mounted on the upper part of the rear clamping device 3, and 7 and 8 move the machining head 9 on the upper head 6 in the left-right direction, that is, in the direction of both strip end faces and the front-back direction, and in the vertical direction between both strip end faces. The welding carriage device 10 is a transmission pipe for transmitting a laser beam generated by the laser oscillator 11, 12 is a preceding welded material not shown here, a preceding strip here, 13 is a succeeding material to be welded, and here is a succeeding strip here. , Arrow A indicates the direction in which the preceding and succeeding strips are transported. FIG. 12 shows an optical system of the above-mentioned conventional laser beam welding apparatus, 14 is a mirror for changing the optical path of the laser beam, and 15 is a condenser lens (or a condenser lens) mounted inside the processing head 9. Mirror 16), and 16 denotes a laser beam.

Next, the operation will be described. In the steel process line, when the strip is subjected to continuous processing such as pickling, plating, and heat treatment, the strip travels in the direction indicated by arrow A in FIG. And
When the strip is fed and reaches the end, the preceding strip 12 becomes the blade width 4a of the shear device 4 as shown in FIG.
Guided inside and stopped. In this state, the leading edge of the trailing strip 13 is fed into the blade width 4a of the shear device 4 and stops. Then, as shown in FIGS. 10 and 13, the back bar device 5 retreats, and the shear device 4 moves forward and is positioned between the front clamp device 2 and the rear clamp device 3. Next, after the strips 12 and 13 are held by the clamping devices 2 and 3, the upper shear blade of the shearing device 4 is lowered to cut the opposing ends of the strips 12 and 13. Subsequently, as shown in FIGS. 11 and 14, the shear device 4 retreats and the back bar device 5
Moves forward and is located between the front clamp device 2 and the rear clamp device 3, and then moves the front clamp device 2 toward the rear clamp device 3 by the blade width 4 a of the shear device 4, and Section and trailing strip 13
To the cut surface. Next, the welding carriage device 8 is moved in the front-rear direction, that is, in such a manner that the processing head 9 is positioned on the joint between the butted strips 12 and 13, that is,
The processing head 9 is moved vertically and set so that the laser beam is moved in a direction perpendicular to the end faces of the strips 12 and 13 and the focal point of the laser beam is at a predetermined height. When the welding preparation is completed in this manner, the laser beam 16 generated by the laser oscillator 11 is changed in direction by the mirror 14 through the transmission pipe 10 as shown in FIG. Accordingly, the welding is started by condensing the light on the both strip joints, and the two strips 12 and 13 are continuously welded by moving the welding carriage device 7 in the left-right direction, that is, in the direction of both strip end faces.

[0004]

The laser welding by the conventional laser beam welding apparatus is performed as described above. However, in this laser beam welding apparatus, the cut shapes of both strips 12 and 13 cut by the shearing device 4 are perfect. 15 (A) and the feed when the front clamp device 2 after cutting is moved by the blade width 4a of the rear shear device 4 on the rear clamp device 3 side. Due to the deviation of the set position resulting from the accuracy, the cut surface of the preceding strip 12 and the cut surface of the following strip 13 are arranged as shown in FIG.
As shown in (B), a minute gap (hereinafter, gap) G is generated. Therefore, in the case of thick plates, generally,
As shown in Japanese Patent No. 76490, if the gap G is small to some extent, filler wire is inserted and welding is performed. However, when the plate thickness is small, that is, when the strips 12 and 13
When the filler wire is less than about 1 mm, when the filler wire is inserted, the finished thickness of the welded portion becomes extremely large, so that the filler wire cannot be inserted. For this reason,
As shown in Japanese Patent No. 272, after cutting, the cut surface is ground by a grinding device. Alternatively, the gap G must be made very small by improving the straightness of the cutting line and the feeding accuracy by increasing the mechanical rigidity or the like to improve the feeding accuracy. According to experiments, for example, when the plate thickness is 0.2 mm, data that the butt gap at the welding start end is within about 30 μm and the butt gap other than the welding start end is up to about 60 μm is obtained. In order to keep the gap at the time of welding within the allowable value, there is a problem that an end face grinding device is added to improve the straightness and feed accuracy of the cutting line, and the size of the device is increased to increase mechanical rigidity. On the other hand, in order to widen the allowable value of the butt gap, a welding method using laser beam defocusing (shifting the focus) and a welding method by scanning a laser beam disclosed in Japanese Patent Application Laid-Open No. 3-234388 are also considered. However, in this case, there is a problem that the welding speed is extremely slow as compared with a normal welding method.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a laser beam welding method capable of performing high-quality and reliable butt welding without increasing the size of the apparatus and reducing the welding speed. The purpose is to obtain a laser beam welding device.

[0006]

Means for Solving the Problems Claim 1 according to the present invention.
The laser beam welding method, in which the laser beam is focused along a butt portion having a small gap between the rear end of the plate-shaped preceding welded material and the front end of the following welded material, and the butt portion is welded. Only at the welding start end of the butt
Laser light is scanned between the materials to be welded and the materials to be welded are fused.
After the contact , the remaining butted portion is welded.

According to a second aspect of the present invention, a laser beam is defocused on both workpieces only at a welding start end of a butt portion to narrow a minute gap, and then the butt portion is welded. .

In the laser beam welding method according to a third aspect of the present invention, a wire is inserted only into the welding start end of the butt portion to weld the materials to be welded, and then the remaining butt portion is welded.

Further, laser beam welding method according to claim 4, in which in claim 3, and adapted to cut the welded portion of the weld starting end vicinity after welding completion.

A laser beam welding apparatus according to a fifth aspect of the present invention is a processing head for condensing a laser beam at a butt portion having a small gap between a rear end of a plate-shaped preceding workpiece and a front end of a following welding workpiece. In a laser beam welding apparatus that moves a processing head along a butt portion and performs welding, a gap sensor that measures a minute gap and a pressing unit that presses the butt portion in a thickness direction in front of the processing head in a welding direction are provided. The pressure of the pressing means can be adjusted according to the minute gap amount measured by the gap sensor.

According to a sixth aspect of the present invention, there is provided a laser beam welding apparatus according to the fifth aspect , further comprising a heating processing head for defocusing and irradiating a part of the laser beam to the abutting portion in front of the pressing means in the welding direction. is there.

A laser beam welding apparatus according to claim 7, wherein the laser beam is focused on a butt portion having a small gap between the rear end of the plate-shaped preceding workpiece and the distal end of the succeeding workpiece. In a laser beam welding apparatus that moves a processing head along a butt portion and welds a butt portion, a heating processing head that defocus irradiates a part of laser light to the butt portion in front of the processing head in a welding direction and a micro head. A gap sensor for measuring a gap is provided so that the defocus of the heating processing head can be adjusted according to the minute gap amount.

[0013]

According to the laser beam welding method of the present invention, the welding start end is welded by melting or expansion due to heating at the welding start end, or the gap at the welding start end is narrowed to enable high quality welding. That is, the allowable gap value at the welding start end can be widened.

In the laser beam apparatus according to the present invention, the gap before the laser beam welding is narrowed by the pressurizing means and the heating head, thereby enabling high quality welding. That is, the allowable gap value can be widened.

[0015]

[Embodiment 1] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG.
FIG. 2 is an explanatory view of the operation of the laser beam welding method according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the laser beam welding device at the welding start end of the first embodiment. In the figure, the components 1 to 14 are the same as in the prior art, and the description thereof is omitted. 1
Reference numeral 7 denotes a welding start end, 17G denotes a gap at the welding start end, 17a denotes a center offset position of the processing head 9, 18 denotes a welding end end, C denotes a gap center, and 19 denotes a laser beam scanning line.

Next, the operation will be described. As a welding method of this kind, the machining head 9 is usually moved along the gap center C.
Is moved from the welding start end 17 to the welding end end 18 side to perform laser beam welding of the butt portion. Here, the center is shifted at the welding start end 17a, and is processed on the trailing strip 13 near the welding start end 17 here. Head 9
Is set, the laser beam is focused, and the subsequent strip 13 is set.
Is heated and melted at the center shift position 17a of the welding start point, and the two strips 12, 13 at the welding start end are welded.
Thereafter, the processing head 9 is moved to the gap center C in the direction of the arrow B along the laser beam scanning line 19a while irradiating the laser beam, and the laser beam is aligned with the laser beam scanning line 19 and the gap center C in the direction of the welding end end 18. Perform welding. As a result, in the laser beam welding of the butt portion where the gap at the welding start end is particularly important, the allowable value of the butt gap at the welding start end in a substantially set state can be increased. According to this welding method, for example, when the welding start end gap exceeds the allowable value of 30 μm (the other butt gap value is 60 μm or less) at a plate thickness of 0.2 mm described above, reliable welding cannot be performed. Even if the welding start end gap is 40 μm, high quality and reliable laser beam welding can be performed.

The reason why the allowable value of the welding start end gap can be increased as described above is as follows. (1) Since the spot diameter at the focal position of the laser beam is very small, when the gap at the welding start end is large, most of the laser beam passes through the gap (without the strip), and the strip becomes It is not melted due to less heat input. However, as described in the first embodiment, at the welding start end, the center shift position 17a
The subsequent strip 13 is heated and melted in advance so that the melted subsequent strip 13 is
2 to the two strips 12, 12 at the welding start end.
It acts to fill the 13 gaps. As a result, the gap between the two strips 12 and 13 at the welding start end is bridged and welded by the melt. (2) Once the welding start end is welded, both the strips 12, 13 are heated by the heat of fusion,
The end faces of both strips extend in the direction to reduce the gap, and are continuously welded to the weld end while forming a melt. (3) At the same time, the absorptivity of the laser beam to the strip increases as the temperature of the strip increases, so that the laser beam applied to the melting portion is efficiently absorbed by the strip, further promoting the melting and narrowing the gap.

In the above embodiment, the processing head is moved along the laser beam scanning line 19a from the center shift position 17a. However, as shown by the laser beam scanning line 19b (dotted line) in FIG. While moving the processing head to a position away from the welding start end 17 by a distance d,
The welding time can be reduced as compared with the above embodiment. In this case, welding cannot be performed up to a position at a distance d from the welding start end 17, but if a non-welded portion (shaded portion N) is cut off by a notch device or the like (not shown), a problem will occur in a subsequent process. Never.

Embodiment 2 FIG. Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG.
FIG. 4 is an explanatory view of the operation of the laser beam welding method according to the second embodiment of the present invention, and FIG. 4 is a cutaway view of the laser beam welding apparatus at the welding start end of the second embodiment. In the figure, the position other than the position of the processing head 9 at the welding start end and the state of the laser beam are the same as those in the first embodiment, and a description thereof will be omitted. Reference numeral 19c denotes a scanning line of the laser beam.

Next, the operation will be described. Welding start end 1
At 7, the laser beam is scanned 19 c by the machining head in the direction perpendicular to both strip end faces around the butting gap center C to melt the welding start ends 17 of the leading strip 12 and the trailing strip 13, and then the scanning is stopped to stop the laser beam. Processing head 9 with irradiation
Is moved in the direction of the welding end 18 along the gap center C to perform laser beam welding of the butted portion. As a result, as in the first embodiment, the allowable value of the butt gap at the welding start end in the substantially set state is increased. According to this method, the welding time can be shortened as compared with the case where the welding is performed while scanning the entire welding line.

Embodiment 3 FIG. Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. FIG.
FIG. 6 is an explanatory view of the operation of the laser beam welding method according to the third embodiment of the present invention, and FIG. 6 is a sectional view of the laser beam welding device at the welding start end of the third embodiment. In the figure, the position other than the vertical position of the processing head 9 at the welding start end and the state of the laser beam are the same as those in the first embodiment, and a description thereof will be omitted.
Reference numeral 20 denotes a defocused laser beam.

Next, the operation will be described. Welding start end 1
At 7, the working head 9 is raised or lowered from a predetermined height at the time of normal welding, and the laser beam is defocused to heat the welding start end 17. Thereafter, while the laser beam is being irradiated, the processing head 9 is moved to a predetermined height at the time of normal welding, and is moved along the gap center C in the direction of the welding end point 18 to perform laser beam welding of the butted portion. As a result, the gap at the welding start end can be narrowed, and the allowable value of the butt gap at the welding start end in a substantially set state can be increased.
According to this method, the welding time can be shortened as compared with the case where the entire welding line is defocused and welding is performed.

Embodiment 4 FIG. In the first and second embodiments, the welding start end 17 is heated and melted by the laser beam to weld the two strips at the welding start end. Has shown that it is possible to increase the tolerance of
As shown in FIG. 7, at the abutting portion between the preceding strip 12 and the following strip 13, the filler wire 21 is inserted into the gap only at the welding start end 17 and laser beam welding is performed. Thereafter, laser beam welding is performed with the filler wire insertion stopped. The same effect as in the first and second embodiments can be obtained as a welding method. In addition, if the welding start end where the finished thickness of the welded portion is increased by this method becomes a problem in the subsequent process (for example, occurrence of thickness variation in the rolling process), it is not described, but after the welding is completed. What is necessary is just to cut off the oblique line N part by a notch device or the like.

Embodiment 5 FIG. In all of the above Examples 1 to 4, it was possible to increase the allowable value of the butt gap of the welding start end in a substantially set state by considering the laser beam welding method at the welding start end. What was shown,
Here, an embodiment using the apparatus will be described below. FIG. 8 is a schematic diagram showing a partial schematic configuration of a laser beam welding apparatus according to Embodiment 5 of the present invention, and shows an operating state. In the figure, 5, 9, 12, 13, 15, 1
Reference numeral 6 is the same as that of the conventional device, and the description thereof is omitted. Reference numeral 22 denotes a roller which presses the abutting portion of the strips 12 and 13 at a position preceding the processing head 9 and 23 denotes a pressing mechanism which presses the roller 22 in the direction of the strips 12 and 13, and these 22 and 23 constitute a pressing means. ing. Reference numeral 24 denotes a half mirror that partially divides the laser beam 16 and changes the direction, 25 denotes a mirror that changes the direction of the laser beam from the half mirror 24, and 26 denotes a heating lens that collects the laser beam from the mirror 25. At 26, a processing head 27 for heating is formed, and strips 12, 1
Heating travel is performed on the abutting portion of No. 3. 28 is strip 1
This is a gap sensor for measuring the gap G of the abutting portions 2 and 13. Arrow D indicates the direction of welding.

Next, the operation will be described. First, as in the conventional example, both ends of the leading strip 12 and the trailing strip 13 are set at predetermined positions with a gap in an abutting state. Next, the laser beam 16 is emitted. First, the butt portion is heated and expanded by the laser beam from the heating head 27 preceding the butt portion of the strip, and the gap is narrowed. Further, the trailing roller 22 passes over this surface and presses against the back bar 5, so that the end of the strip is pressed and deformed, the gap is further narrowed, and the gap is further narrowed when the processing head 9 for performing welding passes. Since welding is performed in the gap state, high-quality welding is possible, and the allowable value of the entire gap can be set larger than in Examples 1 to 4. For example, in this embodiment, the allowable value of the gap at the welding start end for a plate thickness of 0.2 mm is about 50.
μm.

Further, the heating head 2 based on the gap measurement
As shown in FIG. 9, the operation flow of the roller 7 and the roller 22 adjusts the pressing mechanism 23 according to the gap amount measured by the gap measuring sensor 28 to adjust the pressing force of the roller 22 to an appropriate value (for example, when the gap is small, the pressing force is The heating processing head 27 also operates the heating lens 26 in the vertical direction (for example, when the gap is small, the defocus is increased to suppress the heating amount) to adjust the heating amount. By controlling the optimum gap, more stable and high quality welding can be performed. The size of the measurement gap is set in advance to a predetermined value, and the size is determined with respect to the value.

Embodiment 6 FIG. In the above-described embodiment, the pressure means (22, 23) and the heating processing head 27 are set at the same time. However, only one of them may be provided.

[0028]

According to claim 1 of as the present invention above, according to the present invention, after welding the workpieces together by scanning the laser beam between the two workpieces only weld start end of the match-section, the remaining According to the second aspect , the laser beam is defocused on both the materials to be welded only at the welding start end of the butt section to narrow the minute gap, and then the butt section is welded. According to the third aspect , the wire is inserted only into the welding start end of the butt portion, and after welding the materials to be welded, the remaining butt portion is welded.
There is an effect that a laser beam welding method capable of widening the allowable gap value at the welding start end, increasing the size of the apparatus, and performing high-quality and reliable welding without reducing the welding speed is obtained.

According to the fourth aspect of the present invention, the vicinity of the welding start point is cut off after the completion of the welding by the laser beam welding method according to the third aspect . No problem at all.

According to a fifth aspect of the present invention, a processing head for condensing a laser beam on a butt portion having a small gap between a rear end of a plate-shaped preceding workpiece and a front end of a following welding workpiece. In a laser beam welding apparatus that moves a processing head along a butt portion and performs welding, a gap sensor that measures a minute gap and a pressing unit that presses the butt portion in a thickness direction in front of the processing head in a welding direction are provided. A laser beam that can perform high-quality and reliable welding without increasing the size of the equipment because the allowable pressure value of the butting part can be expanded because the pressing force of the pressing means can be adjusted according to the minute gap amount There is an effect that a welding device can be obtained.

According to a sixth aspect of the present invention, in the fifth aspect , a heating processing head for defocusing and irradiating a part of the laser beam to the butting portion in front of the pressing means in the welding direction is provided. In addition, the pressure applied by the pressurizing means can be reduced, and the gap can be easily narrowed.

A laser beam welding apparatus according to claim 7, wherein the laser beam is focused on a butt portion having a small gap between the rear end of the plate-shaped preceding workpiece and the front end of the succeeding workpiece. In a laser beam welding apparatus that moves a processing head along a butt portion and welds a butt portion, a heating processing head that defocus irradiates a part of laser light to the butt portion in front of the processing head in a welding direction and a micro head. A gap sensor for measuring the gap is provided so that the defocus of the heating processing head can be adjusted according to the minute gap amount, so that it is easy to set the allowable gap value and high quality and reliable welding can be performed. There is an effect that a laser beam welding device can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an operation of a laser beam welding method according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the laser beam welding apparatus at a welding start end according to the first embodiment.

FIG. 3 is an operation explanatory view of a laser beam welding method in Embodiment 2 of the present invention.

FIG. 4 is a sectional view of a laser beam welding apparatus at a welding start end according to a second embodiment.

FIG. 5 is an operation explanatory view of a laser beam welding method in Embodiment 3 of the present invention.

FIG. 6 is a sectional view of a laser beam welding apparatus at a welding start end in a third embodiment.

FIG. 7 is an operation explanatory view of a laser beam welding method in Embodiment 4 of the present invention.

FIG. 8 is a schematic diagram illustrating a partial schematic configuration of a laser beam welding apparatus according to a fifth embodiment of the present invention.

FIG. 9 is an explanatory diagram showing an operation flow in the fifth embodiment.

FIG. 10 is a perspective view showing a configuration of a conventional laser beam welding apparatus.

FIG. 11 is a perspective view showing a configuration of a conventional laser beam welding apparatus.

FIG. 12 is an optical path diagram of a conventional laser beam welding apparatus.

FIG. 13 is a side sectional view of a main part for describing an operation state of a conventional laser beam welding apparatus.

FIG. 14 is a side sectional view of a main part for describing an operation state of a conventional laser beam welding apparatus.

FIG. 15 is a strip state diagram for explaining a cut state and a butted state of the strip.

[Explanation of symbols]

9 processing head, 12 preceding strip (preceding welded material), 13 succeeding strip (subsequent welding material), 16
Laser beam, 17 welding start end, 17a welding start end shift position, 17G welding start end gap, 19 laser light scanning line, 19a scan scanning line, 20 defocus, 21 filler wire, 22 roller, 23 pressure mechanism, 27 heating Processing head, 28 gap sensor, G gap.

Continuation of the front page (56) References JP-A-58-74293 (JP, A) JP-A-4-127984 (JP, A) JP-A-4-167987 (JP, A) (58) Fields studied (Int .Cl. ⁶ , DB name) B23K 26/00-26/08 B21B 15/00

Claims (7)

(57) [Claims] 1. A method of welding a butt portion by converging a laser beam along a butt portion having a small gap between a rear end of a plate-shaped preceding workpiece and a front end of a following welding target material. A laser beam welding method, characterized in that the laser beam is scanned between the two materials to be welded only at the welding start end of the butt portion to weld the materials to be welded, and then the remaining butt portions are welded. 2. A method for welding said butt portion by converging a laser beam along a butt portion having a small gap between a rear end of a plate-shaped preceding workpiece and a front end of a following welding target material. A laser beam welding method, characterized in that the laser beam is defocused on both of the materials to be welded only at the welding start end of the butt portion to narrow the minute gap, and then the butt portion is welded. 3. A method of welding a butt portion by converging a laser beam along a butt portion having a minute gap between a rear end of a plate-shaped preceding workpiece and a leading end of a following welding target material. A laser beam welding method, characterized in that a wire is inserted only into a welding start end of a butt portion to weld the materials to be welded, and then the remaining butt portion is welded. 4. The laser beam welding method according to claim 3, wherein after welding is completed, the vicinity of the welding start end is cut off. 5. A processing head for focusing a laser beam on a butt portion having a small gap between a rear end of a plate-shaped preceding workpiece and a front end of a following welding workpiece, and the processing is performed along the butt portion. In a laser beam welding apparatus that welds the butted portion by running a head, a gap sensor that measures the minute gap, and a pressing unit that presses the butted portion in the thickness direction in front of the processing head in a welding direction. A laser beam welding apparatus, wherein the pressure of said pressurizing means can be adjusted according to the minute gap amount measured by said gap sensor. 6. The laser beam welding apparatus according to claim 5, further comprising a heating processing head for defocus-irradiating a part of the laser beam to the abutting portion in front of the pressing means in a welding direction. 7. A processing head for focusing a laser beam on a butt portion having a minute gap between a rear end of a plate-shaped preceding workpiece and a front end of a following welding workpiece, and the processing is performed along the butt portion. In a laser beam welding apparatus that runs a head and welds the butt portion, a heating processing head that defocus irradiates a part of the laser light to the butt portion in front of the processing head in a welding direction, and the micro gap A laser beam welding apparatus comprising: a gap sensor for measuring; and a defocus of the processing head for heating can be adjusted according to a minute gap amount measured by the gap sensor.