JP3087600B2 - Laser welding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting a rear end portion of a preceding metal strip and a front end portion of a following metal strip, butting them against each other, and moving a laser torch along the joining portion. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser welding machine that performs laser welding by means of a laser welding machine that can always perform welding under optimum welding conditions even if the cross-sectional property of a cut surface of a metal strip to be welded changes.

[0002]

2. Description of the Related Art When a strip (hereinafter, referred to as a steel strip) wound around a coil is passed through a processing line continuously for a plurality of coils, a rear end of a steel strip of a preceding coil and a following coil are used. Butt welded to the end of the steel strip to connect and pass the steel strip.

[0003] Of these steel strips, when special steel strips such as stainless steel, high carbon steel and silicon steel are to be butt-welded to pass through, flash butt welding, MIG
Since welding such as welding and TIG welding becomes difficult, laser welding has recently been applied to these special steel strips. In this laser welding, the laser beam is generally welded under welding conditions of a beam diameter of 0.2 to 0.6 mm and a butt gap of 0.05 to 0.3 mm.

[0004] However, in the butt welding of the steel strip as described above, the cut surface of the steel strip serving as the butt surface is the cut surface of the cutting blade of the cutting machine. A uniform butting gap cannot be obtained along the width direction of the steel strip, and when welding is performed in such a state, a portion where the welding strength is reduced occurs, and an operation trouble occurs such that the welded portion is broken during passing. I do.

As a conventional method for preventing the occurrence of such an operation trouble, there is a method disclosed in Japanese Patent Application Laid-Open No. 3-133587. In this method, the butt gap is continuously measured, and the laser torch height, running speed, laser output, and filler wire supply speed are controlled based on the measured values.

[0006]

However, according to the method disclosed in Japanese Patent Application Laid-Open No. Hei 3-133587, when the butt gap is not uniform only along the width direction of the plate, welding is performed under optimum welding conditions. However, when the butt gap is not uniform in the thickness direction, there is a problem that welding cannot always be performed under optimum welding conditions.

The phenomenon that the butting gap becomes non-uniform in the thickness direction is based on the following. That is, the butt surface of the steel strip is formed by cutting the end of the steel strip in the width direction with a cutting blade,
When observing the cut surface of the steel strip, the cutting edge cuts into the steel strip, so that the cutting sag is formed first, and then the cut surface is formed.

[0008] Then, a fracture surface is formed by cracks generated in the thickness direction, and burrs are further formed.

The ratio of the above-mentioned fractured surface to the total cross-section is
Although the number of cutting blades is small when they are new, they increase when the cutting blade wears and the sharpness deteriorates, and the amount of burrs increases.

The thickness of the steel strip at each position in the width direction is not uniform. Normally, the thickness becomes thinner as it approaches the both ends in the width direction, as compared with the thickness at the center of the width. Therefore, the ratio of the fractured surface to the entire cross-section and the degree of burr generation differ at each position in the width direction.

[0011] Further, even when the clearance between the upper blade and the lower blade of the cutting blade is not appropriate, the ratio of the fractured surface increases and burrs are generated.

When the butting surfaces of the steel strip having a cut surface and a fractured surface are butted with a certain gap, even if the cutting blade is not worn, as shown in FIG. Cutting surface 21b following cutting sagging 21a of 21
And a cutting surface 22b following the cutting sag 22a of the succeeding steel strip 22
DOO gap portion where the facing is a predetermined value (w ₀₎ is even though, of the portion fractured surface 22c of the fracture surface 21c and the following steel strip 22 of the prior steel strip 21 facing the gap (w ₁₎
Tend to be larger than w ₀ . In a state where the cutting blade is worn, as shown in FIG.
The gap (w ₂ ) at the portion where the fracture surface 21c of the subsequent steel strip 22 and the fracture surface 22c of the succeeding steel strip 22 face each other is much larger than w ₀ . Further, as shown in FIGS. 15A and 15B, even when burrs 21d and 22d are generated,
If welding is performed under the same conditions as when the burrs 21d and 22d do not occur, welding cannot be performed well.

Therefore, it is not sufficient to simply set the welding conditions only by the gap between the butted surfaces, and it is necessary to set the welding conditions by grasping the cross-sectional properties of the butted surfaces.

The present invention has been made to solve the above-mentioned problems of the prior art, and provides a laser welding machine which can perform welding under welding conditions according to the cross-sectional properties of a butt surface. It is intended to be.

[0015]

A laser welding machine according to the present invention cuts a rear end portion of a preceding metal strip and a front end portion of a following metal strip and abuts each other with a cut surface, and applies a laser torch to the protruding portion. In a laser welding machine that performs laser welding by running along a joining portion, a fracture surface detector that grasps an area ratio of a fracture surface at each position in a width direction of a butt surface of a metal strip, and a burr generation degree at each position in the width direction. A burr detector, a thickness measurement device for measuring the thickness at each position in the width direction, a laser output and a welding speed based on signals from the fracture surface detector, the burr detector and the thickness measurement device. And a calculator for calculating the supply speed of the filler wire, and a controller for controlling the laser output, the welding speed, and the supply speed of the filler wire by a command from the calculator. , And it has a.

[0016]

The cross section at each position along the width direction of the abutting surface of the strip can be accurately grasped by the fracture surface detector, the burr detector and the thickness measuring device. Then, based on the grasped cross-sectional properties, the permanent condition adapted to the cross-section is set.

[0017] Therefore, since optimum welding can be performed at each position in the width direction of the strip, no welding defect occurs, and no line trouble such as plate breakage occurs.

[0018]

FIG. 1 shows a laser welding machine according to an embodiment of the present invention. FIG. 1 is a block diagram showing the configuration of the laser welding machine. This laser welding machine includes a fracture surface detector 1 for detecting an area ratio of a fracture surface at each position in a width direction of a butt surface of a strip to be welded (hereinafter, described as a steel strip) with respect to an entire cross section. A burr detector 2 for detecting the degree of burr occurrence at each position in the width direction of the mating surface, a thickness measuring device 3 for measuring a thickness at each position in the width direction, a fracture surface detector 1, a burr detector 2, And a welding condition calculator 4 for calculating a laser output, a welding speed, and a supply speed of the filler wire at each position in the width direction of the butt surface based on signals from the welding condition calculator 3 and the signal from the welding condition calculator 4. A laser welding machine having a controller 5 for controlling the laser output, welding speed and filler wire supply speed according to commands, a laser transmitter 6, a laser torch running motor 7, and a filler wire supply motor 8. Composed of a body.

Next, a case where the laser welding machine according to the embodiment of the present invention is used in combination with a double cut shear will be described as follows.

First, the equipment configuration will be described with reference to the front view of FIG. 2. A double cut shear 101 is a shear carriage 32 movable along a rail 31 in the width direction of a steel strip.
A gate-shaped shear frame 33 mounted on the shear carriage 32;
An upper blade holder 36 which is raised and lowered along two guides 35 by a lifting cylinder 34 provided on the upper frame 33a of the third upper frame 33a, and an upper blade 37 mounted on the upper blade holder 36.
A lower blade holder 40 that is raised and lowered along two guides 39 by a lifting cylinder 38 provided on the shear carriage 32; a lower blade 41 mounted on the lower blade holder 40; 42.

The back carriage 43 is provided adjacent to the shear frame 33 on the shear carriage 32 when welding the steel strips together.
Numeral 3 is configured to be able to move up and down along two guides 45 by a lifting cylinder 44.

A frame 4 is provided above the backing metal 43.
6 is provided with a horizontal rail 47 supported by a welding carriage traveling motor 7a (having the same function as the laser torch traveling motor 7) via a guide 48.
Are arranged so as to be movable along the horizontal rail 47. The welding carriage 49 includes:
A laser torch 51 having a built-in condenser lens 50, a guide 52 for raising and lowering the laser torch 51, a filler wire supply motor 8a for supplying a filler wire 53, a laser oscillator 6a, and a laser oscillator 6a
A bender mirror 54 for changing the direction of the laser light sent from the vehicle is mounted, and a steel strip placed on the backing metal 43 can be welded in the width direction.

As shown in the side view of FIG. 3, the apparatus for clamping a steel strip at the time of laser welding comprises a preceding steel strip which clamps a rear end portion of a preceding steel strip 21 from above and below with the double cut shears 101 interposed therebetween. It is composed of a band clamp device 55 and a trailing steel band clamp device 56 for clamping the leading end of the trailing steel band 22 from above and below.

The preceding steel strip clamping device 55 has a clamp table 57 for supporting the preceding steel strip 21 below, and a clamp 59 for holding the preceding steel strip 21 from above by operating the elevating cylinder 58 in conjunction with the clamp table 57. And a guide 61 that is connected below the clamp table 57 and slides along the rail 60 in the line direction to abut the rear end cut surface of the preceding steel strip 21 and the front end cut surface of the subsequent steel strip 22.
It is composed of

Similarly, the following steel strip clamping device 56
Is a clamp table 62 for supporting the succeeding steel strip 22 at a lower position, and a clamp 64 for operating the elevating cylinder 63 in conjunction with the clamp table 62 to clamp the following steel strip 22 from above.
And a guide 66 which is connected below the clamp table 62 and slides in the line direction along the rail 65 to abut the rear end cut surface of the preceding steel strip 21 and the front end cut surface of the subsequent steel strip 22. It is configured.

In the equipment configuration as described above, the fracture surface detector 1 and the burr detector 2 are, as shown in FIG. 2 and FIG.
Attached to. Further, as shown in FIG. 4, the sheet thickness measuring device 3 is used for measuring the rear end portion of the preceding steel strip 21 and for the following steel strip 2.
2 for measuring the tip part, and each upper measuring terminal 3
a and 3b are connected to the upper blade holder 36 of the double cut shear 101 via the elevating cylinders 67a and 67b.
The lower measuring terminals 3c and 3d are attached to the lower blade holder 40 of the double-cut shear 101 via lifting cylinders 67c and 67d.

Next, a method of welding a steel strip when the above-described laser welding machine is used in combination with a double cut shear will be described with reference to FIGS.

First, the rear end of the preceding steel strip 21 and the front end of the following steel strip 22 are moved so as to be located at predetermined positions when welding with a laser welding machine. The belt 22 is stopped.

The lifting cylinders 58 and 6
Activate 3 to lower clamps 59 and 64,
The leading steel strip 21 and the following steel strip 22 are clamped between the clamp tables 57 and 62, respectively.

Next, the upper measuring terminal 3 of the thickness measuring device 3
a and 3b are respectively moved up and down cylinders 67a and 67
7b to lower the lower measuring terminal 3
c and 3d are respectively transferred to the lifting cylinders 67c and 6c.
7d is actuated to raise the measuring terminals 3a and 3
c is brought into contact with the front and back surfaces of the preceding steel strip 21, and the measurement terminals 3 b and 3 d are brought into contact with the front and back surfaces of the subsequent steel strip 22. Then, the zero point correction of each plate thickness measuring device 3 is performed.

Next, the shear holder 42 is raised, and the shear carriage 32 is moved along the rail 31 in the width direction of the steel strip (to the left in FIG. 2). At this time, the thickness measuring device 3 scans in the width direction of the steel strip as the shear carriage 32 moves. From the sum of the vertical movement amounts of the upper measurement terminal 3a and the lower measurement terminal 3c at this time, the plate thickness at each position in the width direction of the preceding steel strip 21 and the upper measurement terminal 3b and the lower measurement terminal 3d are determined. From the sum of the respective vertical movement amounts, the plate thickness at each position in the width direction of the preceding steel strip 22 can be measured.

Next, the shear carriage 32 is located at a position where the rear end of the preceding steel strip 21 and the front end of the following steel strip 22 can be cut, that is, the upper blade 37 of the double cut shear 101.
When the lower blade 41 reaches above and below the preceding steel strip 21 and the following steel strip 22, the shear carriage 32
Is stopped, the shear holder 42 is lowered, and the shear frame 33 is fixed. At this time, the upper measuring terminals 3a and 3b of the sheet thickness measuring device 3 which has completed the sheet thickness measurement are moved up to the ascending limit by operating the lifting cylinders 67a and 67b, respectively, and the lower measuring terminals 3c and 3d are respectively moved to the lifting cylinder Activate 67c and 67d to lower to the lower limit.

Next, as shown in FIG. 3, the lower blade holder 40 is raised by the lifting cylinder 38 until the lower blade 41 contacts the preceding steel strip 21 and the following steel strip 22.
Then, the upper blade holder 36 in the state shown in FIG.
As shown in (1), it is lowered by the lifting cylinder 34, and the rear end of the preceding steel strip 21 and the front end of the following steel strip 22 are cut by the upper blade 37 and the lower blade 41.

Next, the guide 61 is slid along the rail 60, and the preceding steel strip 21 is advanced in the steel strip advancing direction by a predetermined amount while being clamped by the clamp table 57 and the clamp 59. In addition, the guide 66 is slid along the rail 65, and the trailing steel strip 22 is retracted by a predetermined amount in the traveling direction of the steel strip while being clamped by the clamp table 62 and the clamp 64. Then, the lower blade holder 40 is lowered by a predetermined amount by the lifting cylinder 38. Note that the upper blade holder 36 remains in a lowered state at the time of cutting.

Next, the shear carriage 32 is moved along the rail 31 in the opposite direction (rightward in FIG. 2). Then, as the shear carriage 32 moves, the cross-sectional shapes of the preceding steel strip 21 and the following steel strip 22 at each position in the width direction are detected by the fracture surface detector 1 and the burr detector 2.

When the backing metal 43 reaches a position below the preceding steel strip 21 and the following steel strip 22 with the movement of the shear carriage 32, the movement of the shear carriage 32 is stopped.

Next, the guide 66 is slid along the rail 65, and the following steel strip 22 is moved in the traveling direction of the steel strip so that a predetermined amount of abutment with the preceding steel strip 21 can be maintained. To move forward. Then, the backing metal 43 is raised by the elevating cylinder 44 to make contact with the back surfaces of the preceding steel strip 21 and the following steel strip 22.

Next, the welding carriage traveling motor 7a is driven to move the welding carriage 49 to the guide 4.
The guide 8 is moved to the welding start position along the horizontal rail 47 while being guided. And the laser torch 51
The guide 52 is moved down to a predetermined focal position. Then, the welding condition calculator 4 calculated based on the signals from the fracture surface detector 1, the burr detector 2, and the plate thickness detector 3.
The correction amount at each position in the width direction of the steel strip with respect to the preset standard laser output, welding speed, and filler wire supply speed is transmitted to the laser oscillator 6a and the welding carriage traveling motor 7a via the welding control device 5.
And output to the filler wire supply motor 8a,
The butt surfaces of the preceding steel strip 21 and the following steel strip 22 are welded.

Next, the case where the laser welding machine according to the embodiment of the present invention is used in combination with a rotary shear will be described as follows. That is, first, the equipment configuration will be described with reference to FIG. 6. The rotary shear 102 is provided horizontally on a base 71, a shear frame 72 mounted on the base 71, and an upper frame 72 a of the shear frame 72. It has a pair of rails 73 and a screwing portion that is screwed to a screw bar 74 that is rotated by a screw bar drive motor 7b (which has the same function as the laser torch traveling motor 7). A carriage 75 which moves in the width direction of the steel strip along the shaft, a shear holder 77 mounted on the carriage 75 so as to be able to move up and down by an elevating cylinder 76, and a shear holder 77
And an upper round blade 78a and a lower round blade 78b mounted on the lower blade.

The laser welding machine includes a laser torch 79 having a built-in condensing lens 79 mounted on the carriage 75 in parallel with a shear holder 77, and a mechanism for raising and lowering the laser torch 79. 7, a bender mirror 81 attached to the rear end of the laser torch 79 to change the direction of the laser beam from the laser oscillator 6b, and a filler wire 82 as shown in the side view of FIG.
Wire feed motor 8 which feeds to the tip of
b. Then, the backing metal 84 raised and lowered by the lifting cylinder 83 by the laser torch 79.
The butted portion of the preceding steel strip 21 and the following steel strip 22 placed on the upper part can be welded in the sheet width direction.

As shown in the side view of FIG. 7, the apparatus for clamping a steel strip at the time of laser welding includes a preceding steel strip which clamps the rear end of the preceding steel strip 21 from above and below with the rotary shear 102 interposed therebetween. It is constituted by a band clamp device 85 and a trailing steel band clamp device 86 for clamping the leading end of the trailing steel band 22 from above and below.

The preceding steel strip clamping device 85 comprises a clamp table 87 for supporting the preceding steel strip 21 at a lower position, and a clamp 89 for clamping the preceding steel strip 21 from above by operating the elevating cylinder 88 in conjunction with the clamp table 87. And a guide 91 which is connected below the clamp table 87 and slides in the line direction along the rail 90 to abut the rear end cut surface of the preceding steel strip 21 and the front end cut surface of the subsequent steel strip 22.
It is composed of

Similarly, the following steel strip clamping device 86
Is a clamp table 92 for supporting the succeeding steel strip 22 at a lower position, and a clamp 94 for clamping the subsequent steel strip 22 from above by operating the elevating cylinder 93 in conjunction with the clamp table 92.
And a guide 96 that is connected below the clamp table 92 and slides in the line direction along the rail 95 to abut the rear end cut surface of the preceding steel strip 21 and the front end cut surface of the subsequent steel strip 22. It is configured.

In the equipment configuration as described above, the fracture surface detector 1 and the burr detector 2 are attached to an upper holder 97 connected horizontally to a shear holder 77 of a rotary shear 102 as shown in FIG. I have. Further, there are two thickness measuring devices 3 for the preceding steel strip 21 and the following steel strip 22, and the upper measuring terminals 3a and 3b, respectively.
Are connected to lifting cylinders 98a and 98b attached to the upper holder 97, and the lower measuring terminals 3
c and 3d are connected to a shear holder 77 in the horizontal direction, and are connected to lifting cylinders 98c and 98d attached to a lower holder 99 parallel to the upper holder 97.

Next, a method for welding a steel strip when the above-described laser welding machine is used in combination with a rotary shear will be described.

First, the rear end of the preceding steel strip 21 and the front end of the following steel strip 22 are moved so as to be located at predetermined positions when welding with a laser welding machine. The belt 22 is stopped.

The lifting cylinders 88 and 9
Activate 3 to lower clamps 89 and 94,
The leading steel strip 21 and the following steel strip 22 are clamped between the clamp tables 87 and 92, respectively.

Next, the shear holder 77 is lowered by the lifting cylinder 76 to a height at which the preceding steel strip 21 and the following steel strip 22 can be cut. At the same time, as shown in the side view of FIG. 8, the upper measuring terminals 3a and 3b of the sheet thickness measuring device 3 are lowered by operating the lifting cylinders 67a and 67b, respectively, and the lower measuring terminals 3c and 3d are respectively lowered by the lifting cylinder. The measurement terminals 3a and 3c are brought into contact with the front and back surfaces of the preceding steel strip 21, and the measurement terminals 3b and 3d are brought into contact with the front and back surfaces of the succeeding steel strip 22 by operating the 67c and 67d. Then, the zero point correction of each plate thickness measuring device 3 is performed.

Next, the carriage 75 is moved along the rail 73 in the width direction of the steel strip (to the left in FIG. 6). Then, as shown in the side view of FIG.
By the upper round blade 78a and the lower round blade 78b attached to the
The rear end of the preceding steel strip 21 and the front end of the following steel strip 22 are cut.

At the same time as the cutting of the steel strip, FIG.
In the state shown in (1), the cut surfaces of the steel strips 21 and 22 are determined by the fracture surface detector 1 and the burr detector 2 attached to the shear holder 77, and the steel strip 21 is measured by the plate thickness measuring device 3.
And 22 are detected at each position in the width direction.

When the cutting is completed, the lifting cylinder 7
By 6, the shear holder 77 is raised to the upper limit. Then, the guide 96 is moved in the line direction along the rail 95, and the following steel strip 22 is advanced in the steel strip traveling direction,
The gap between the cut surface of the preceding steel strip 21 and the cut surface of the subsequent steel strip 22 is set to a predetermined gap amount at the time of laser welding.

Next, the laser torch 79 is lowered by the guide 80 to a predetermined welding position. At the same time, the screw bar drive motor 7b is driven to rotate the screw bar 74, and the shear holder 77 screwed to the screw bar 74 is advanced in the width direction of the steel strip (to the right in FIG. 6), and the laser torch is used. Position 79 at the welding start point.

A standard laser output, welding speed and filler set in advance, calculated by the welding condition calculator 4 based on signals from the fracture surface detector 1, the burr detector 2, and the plate thickness detector 3. The correction amount at each position in the width direction of the steel strip with respect to the wire supply speed is output to the laser oscillator 6b, the screw bar drive motor 7b and the filler wire supply motor 8b via the welding control device 5, and the leading steel strip 21 and the following steel The butted surfaces of the band 22 are welded.

In any of the cutting mechanisms, as the fracture surface detector 1, for example, a shape detector using helium neon laser light is used, and the laser light reflection angle between the cut surface and the fracture surface changes. Utilizing this fact, the fracture surface ratio is detected.

Further, by using a CCD camera and performing image processing using the difference in shading between the cut surface and the fracture surface, the fracture surface ratio may be detected.

The thickness measuring device 3 may use a displacement meter using a magnescale, the tip of which is cylindrical, and which is easy to scan in the width direction. Then, these may be arranged vertically with the steel strip interposed, and the thickness of the sheet may be measured by the displacement of the upper and lower magnescales when scanning in the sheet width direction. Although the contact type is used as the thickness measuring device 3 in the embodiment, a non-contact type thickness measuring device using radiation may be used.

The burrs were evaluated by using the reflection angle of the laser beam in the direction of the plate thickness where the reflected light was not generated, and where the reflected light was not generated, the plate thickness end was taken as the apparent plate thickness including the burrs. Is measured, and the true plate thickness measured by the plate thickness measuring device 3 is subtracted from the plate thickness, whereby the size of the burr at each position in the width direction can be evaluated.

The apparent thickness including burrs may be measured by image processing with a CCD camera.

Next, an example of controlling the laser output, welding speed and filler wire supply speed will be described.

(1) When the Cutting Blade is Normal As shown in FIG.
Since the plate thickness is reduced at both plate ends 1 and 22, in order to prevent the occurrence of blow holes due to excessive penetration, FIG.
As shown in the graph of 0 (b), the laser output is reduced and the welding speed is increased at both plate ends. In FIG. 10A, reference numeral 21b or 22b is a cut surface, reference numeral 21c or 22c is a fractured surface, and reference numerals 21d or 22d shown by dotted lines are burrs (the same reference numerals are used in FIGS. 11 and 12). ).

(2) When the wear of the cutting blade is slightly advanced As shown in FIG. 11A, when the wear of the cutting blade is slightly advanced and the ratio of the fracture surface is increased, in order to prevent excessive penetration. As shown in the graph of FIG. 11B, at both ends of the plate, the laser output is decreased and the filler wire supply speed is increased as compared with the case of (1). In particular, both ends of the steel strip have a fracture surface 21c (22
Since the ratio of c) increases, the filler wire supply speed at both ends is further increased. On the other hand, to obtain good penetration, the welding speed is reduced.

(3) When the wear of the cutting blade progresses greatly and a lot of burrs are generated As shown in FIG. 12A, the wear of the cutting blade progresses greatly and a large amount of burrs 21d (22d) are generated. When this happens, the gap on the back side in the thickness direction becomes extremely large. Therefore, as shown in the graph of FIG. 12B, the laser output is greatly reduced, and the filler wire supply speed is increased. In particular, since blowholes are easily generated at both ends, the filler wire supply speed is rapidly increased to increase the supply amount of the filler wire. On the other hand, to improve the penetration, the welding speed is reduced.

As described above, the laser welding machine of the present invention can sufficiently form beads on the back side while preventing the occurrence of blow holes.

FIG. 13 shows the welding strength of the welded portion welded by the laser welding machine according to the present invention in terms of the number of times of repeated bending (the number of times of bending up to weld cracking) used as an index. It can be seen that the number of times of repeated bending is improved by almost twice as compared with the case of welding with the welding machine of No. 1.

FIG. 14 is a graph showing the number of breaks per month of a welded portion in an actual rolling line in comparison with the conventional case and the case of the present invention. As is apparent from this figure, the number of fractures of the welded portion per month is reduced to about 1/3 as compared with the conventional example according to the present invention, and it is understood that the present invention has a great effect.

[0066]

According to the present invention, welding can be performed under optimum welding conditions according to the cross-sectional properties of the butt surface.
The degree of occurrence of welding defects was reduced, and line troubles due to steel strip fracture were reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a laser welding machine according to an embodiment of the present invention.

FIG. 2 is a front view showing the relative positional relationship between the laser welder and the equipment configuration of the double cut shear when the laser welder of the embodiment of the present invention is used in combination with a double cut shear.

FIG. 3 is a side view of the clamp device.

FIG. 4 is a side view showing details of the thickness detector;

FIG. 5 is a side view showing a state where a rear end of a preceding steel strip and a front end of a following steel strip are simultaneously cut by a double cut shear.

FIG. 6 is a front view showing the equipment configuration and the relative positional relationship between the laser welding machine and the rotary shear when the laser welding machine according to the embodiment of the present invention is used in combination with a rotary shear.

FIG. 7 is a side view showing a filler wire supply motor portion and a clamp device.

FIG. 8 is a side view showing the details of the thickness detector.

FIG. 9 is a side view showing a state in which a rear end of a preceding steel strip and a front end of a following steel strip are simultaneously cut by a rotary shear.

10A and 10B are explanatory diagrams showing a cutting state when a cutting blade is normal, (a) is a cross-sectional view of a steel strip in a width direction showing a cross-sectional property of a butt surface, and (b) is a diagram of each position in a width direction. It is a graph which shows the change of laser output, welding speed, and filler wire supply speed corresponding to the change of cross-sectional property.

11A and 11B are explanatory diagrams showing a cutting state when wear of the cutting blade has slightly progressed, in which FIG. 11A is a cross-sectional view of a steel strip showing a cross-sectional property of a butt surface, and FIG. It is a graph which shows the change of the laser output, welding speed, and filler wire supply speed corresponding to the change of the cross-sectional property of each position.

FIG. 12 is an explanatory diagram showing a cutting state in a case where wear of a cutting blade has greatly progressed and a lot of burrs have occurred, and FIG. 12 (a) is a cross-sectional view in a width direction of a steel strip showing a cross-sectional property of a butt surface; (B) is a graph showing changes in laser output, welding speed, and filler wire supply speed corresponding to changes in cross-sectional properties at various positions in the width direction.

FIG. 13 is a graph of the number of times of repeated bending comparing the case of the present invention and the conventional case.

FIG. 14 is a graph of the number of breaks per month comparing the case of the present invention and the conventional case.

FIGS. 15A and 15B are explanatory diagrams showing properties of a cut surface, where FIG. 15A shows a case where the cutting blade is a property, and FIG. 15B shows a case where the cutting blade is worn.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fracture surface detector 2 Burr detector 3 Plate thickness measuring device 4 Welding condition calculator 5 Controller 6 Laser transmitter 7 Laser torch running motor 8 Filler supply motor 9 Laser welding machine

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-60-118417 (JP, A) JP-A-2-147186 (JP, A) JP-A-3-5089 (JP, A) JP-A-3- 13289 (JP, A) JP-A-3-133587 (JP, A) JP-A-2-11685 (JP, U) JP-B-4-42077 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 26/00-26/26 B21C 47/26

Claims (1)

(57) [Claims] 1. A laser welding method in which a rear end of a preceding metal strip and a front end of a following metal strip are cut, but the cut surfaces thereof are butted, and a laser torch is run along the butted portion to perform laser welding. In the machine, a fracture surface detector for grasping the area ratio of the fracture surface at each position in the width direction of the butting surface of the metal strip, a burr detector for detecting the degree of burr occurrence at each position in the width direction, and each position in the width direction A thickness measuring device for measuring the thickness of the plate, and a calculator for calculating a laser output, a welding speed and a supply speed of the filler wire by a signal from the fracture surface detector, the burr detector and the thickness measuring device, A controller for controlling the laser output, the welding speed, and the supply speed of the filler wire in accordance with a command from the arithmetic unit.