JPH0465756B2 - - Google Patents

Description

[Detailed Description of the Invention] <Object of the Invention> Industrial Field of Application The present invention relates to a laser welding method and an apparatus therefor, and more specifically, the present invention relates to a laser welding method and an apparatus for the same, and more particularly, the present invention relates to a laser welding method and an apparatus for cutting the rear end of a leading steel strip and the leading end of a trailing steel strip. When laser welding is performed by butting these two cut surfaces as abutting surfaces, the abutting surfaces of both steel strips are accurately abutted on the work table of this welding device to form a butt line, and then this line is formed by optical means. A method and device for laser welding by enlarging the butt line and moving or rotating the work table to accurately match the butt line with the travel line of the welding torch, and the method and apparatus for laser welding, especially for sheets with a thickness of 0.35 mm or less (particularly The present invention relates to a laser welding method and apparatus suitable for laser welding ultra-thin and wide steel strips with a plate width of about 1.5 m or more (approximately 0.2 mm or less) by reliably butting and laser welding them over the entire width with high precision.

Conventional technology Traditionally, in continuous processing lines for steel strips,
Steel strips are joined by butt welding to ensure continuous rolling and other treatments (hereinafter referred to as treatment processes). On the other hand, before supplying the steel strip as a product to customers, etc., it undergoes processing such as rewinding, winding, welding, slitting, and cutting (hereinafter referred to as
It is called seisei processing. ), and in particular, they are joined by butt welding, adjusted to the unit weight required by the customer, or cut and sent out as products. In particular, unlike the welds in the former treatment process, the welds during the latter finishing process are sent out as products with almost no maintenance after welding, so welds with a high quality are required. has been done.

In addition, among steel strips, recent silicon steel strips are required to be thin in order to reduce power loss, and products are rolled to a thickness of about 0.2 mm or less, and in the finishing process, they are rolled to an extremely thin state. will be welded,
Even with such ultra-thin steel strips, it is required that high quality welds be formed during welding.

In other words, since silicon steel strip is processed as a product on a high-speed, continuous punching line, etc. at the customer's end, welding in the latter finishing process requires (1) the side edges of the steel strip to be straight and straight; be parallel to the center line of both steel strips, (2) the thickness of the welded part must be uniform and meet certain standards, and the surface must be flat; (3) the mechanical properties of the welded part must meet certain standards. (4) There should be no bending or misalignment in at least part of the weld, and these requirements are becoming stricter year by year.

Further, grain-oriented silicon steel strips tend to become thinner, from about 0.35 to 0.30 mm to about 0.23 to 0.15 mm, and the thickness of the grain-oriented silicon steel strips tends to become even thinner in order to reduce power loss.

From these points, if we apply laser butt welding to welding silicon steel strips for finishing treatment, instead of using conventional butt welding such as TIG or MIG,
The laser diameter can be reduced to about 0.1 mm and the energy density is extremely high, so the heat affected zone can be reduced, the surface of the weld can be flattened, and the bead width can be reduced. In particular, in order to satisfy conditions (1) and (2), it is necessary to achieve highly accurate matching.

That is, in butt welding of thin materials, burn-through tends to occur at the weld start and end ends, and to prevent this, so-called "crater treatment" is performed. In this process, the deviation of both ends of the butt line for both the leading and trailing steel strips to be butted is 0.05 mm.
It is necessary for the butt line to be within the range of , and the butt line also needs to be perpendicular to the center of both steel strips and aligned in a straight line, but conventional butt technology has not been able to achieve these conditions. Can not. For example, Tokko Akira
No. 59-50435 discloses that the opposing ends of both leading and trailing steel strips are simultaneously cut at the cutting position of the welding line using a double cut shear, and then each cut surface is moved to the welding position, where each cut surface is A welding device has been proposed that performs welding along the butt line after abutting surfaces. At the cutting position and welding position of this welding position, in order to align the side edge of the steel strip parallel to the center line of the welding line as in the condition (1) above, the welding line is placed on the side edge of the guide table, work table, etc. Side guides are installed parallel to the center line, and when cutting or welding, one side edge of the steel strip is brought into contact with these side guides, and the shear or welding machine is run along a path perpendicular to each side guide. In particular, the ends of the steel strip are cut or butt welded. In addition, the work table is configured to be able to slide freely in the direction of the running line of the steel strip, and to be able to rotate freely around the intersection of the extension line of the side guide and the running line of the laser welding torch. In addition, by moving each end of the trailing steel strip in the direction of the steel strip running line of the work table, or by turning, etc., the butt line of both the leading and trailing steel strips is aligned with the running line of the laser welding torch.
At this welding position, the butt line can match the welding torch traveling line relatively well, but since there is no detection mechanism for this, and there is no fine adjustment mechanism for rotating or moving the work table, for example, the plate thickness is 0.35 mm. Below is the board width
When the steel strip is extremely thin and wide, such as 1.5 m or more, it is extremely difficult to match the welding torch running line and the butt line accurately to match the steel strip. In other words, the welding torch traveling line must be accurately aligned with the butt line by visual inspection.In other words, there is a limit to alignment, and a high-precision butt groove suitable for laser welding of ultra-thin and wide steel strips can be formed. I can't.

In addition, if the steel strip is thin, it is extremely dangerous to handle it manually as it often cuts your hands and fingers.
Furthermore, since both the leading and trailing steel strips are cut using a double-cut shear at the cutting position, the two cutting lines do not match when they are butted together, resulting in misalignment, etc., and it is difficult to laser weld uniformly across the width. difficult to do.

Problems to be Solved by the Invention The present invention aims to solve the above problems. Specifically, each end of the leading steel strip and the trailing steel strip is cut, and this cut surface is Move the worktable parallel to one reference side of the worktable, or move it parallel to one reference side of the worktable so that the butt line matches the welding torch travel line exactly and with high precision. When turning at the intersection with the laser welding torch travel line, the butt line is enlarged by optical means, and the work table is moved or rotated by a numerically controlled motor to match the butt line and the welding torch travel line with high precision. This paper proposes a method and apparatus for laser butt welding.

<Structure of the Invention> Means for Solving the Problems and Their Effects That is, in the laser welding method according to the present invention, after cutting the rear end of the leading steel strip and the leading end of the trailing steel strip,
These cut surfaces are butted against each other on a work table to form a butt line, and when laser welding is performed by running a laser welding torch along this butt line, one reference side surface of this work table and the torch of the laser welding torch are moved along the butt line. While magnifying and observing the point corresponding to the intersection with the line using a microscope that moves along a path that matches the torch travel line, the work table is numerically controlled and moved in a direction parallel to one reference side surface. Then, align one end of the butt line with the intersection point, and then use the other microscope, which moves along a path that matches the torch travel line, to magnify and observe the other end of the butt line while aligning the work table with the intersection point. numerically controlled rotation around the center of rotation to bring the other end of the butt line to the center of the scale of the field of view of the other microscope, aligning the butt line with the torch travel line,
After that, a laser welding torch is run to carry out laser welding.

Additionally, suitable equipment for carrying out this method is:
A laser welding device that cuts the rear end of the leading steel strip and the tip of the trailing steel strip, butts these cut surfaces together on a work table, and runs a laser welding torch along this butt line to perform laser welding. a first numerically controlled motor that numerically controls and moves the worktable in a direction parallel to one reference side surface of the worktable;
A second numerically controlled motor is provided to numerically control and rotate the work table with the intersection of one reference side surface and the travel line on which the torch should travel as the center of rotation, and the work table is enlarged at the point corresponding to the intersection of the butt lines. an optical magnifying device that enables observation based on a field of view scale and is connected to a first numerically controlled motor; An optical magnifying device connected to the torch is provided so as to be able to reciprocate along a path that coincides with the torch traveling line.

The following is a more specific explanation of the configuration of these means with reference to the drawings.

Note that FIG. 1 is a side view of a laser welding device as an example of a device for carrying out the method of the present invention, and FIG. 3A and 3B are plan views showing the state in which the end portion of the steel strip is cut in the laser welding apparatus shown in FIG. 1.

First, in Fig. 1, numeral 1 indicates the preceding steel strip, 2
indicates a trailing steel strip, and the leading steel strip 1 is fed into this welding line via a threading table 23 by a pair of upper and lower pinch rollers 3 and 4 provided on the upstream side, and is cut into a pair at cutting position A as described later. After being cut by the shears 7 and 8 of It is fed in, cut by a pair of shears 7 and 8, and conveyed again to welding position B by a pair of upper and lower pinch rollers 3 and 4. That is, the cutting device 5 is provided at the cutting position A, and the cutting device 5
A pair of scale shear frames 6 (only one frame 6 is shown in FIG. 1) are installed approximately parallel to the center line of the welding line or the traveling direction of the leading steel strip 1 and the trailing steel strip 2. A pair of upper and lower shears 7 and 8 are arranged at intervals and are provided between these scaler frames 6 so as to be movable up and down. Therefore, as shown in FIG.
After aligning the parts b as described below, the rear end portion 1a is cut along the cutting line 36 by a pair of upper and lower shears 7 and 8 to form an abutting surface 1c. Trailing steel strip 2
Similarly, as shown in FIG. 3b, the tip end portion 2a of
It is cut at the top to form the abutting surface 2c. That is, during cutting, the opening/closing table 34 is opened by the cylinder 35, and the upper and lower shears 7, 8 are inserted into this open part.
is lowered to cut each end 1a, 2a of the steel strips 1, 2, and the scrap of the rear end 1a of the preceding steel strip 1 is removed from the opening. In addition, these two steel strips 1,
In order to fix the ends 1a, 2a of both steel strips 1, 2 when cutting the steel strips 2, electromagnetic chucks 9, 10 are placed on the exit side and the entry side, sandwiching the pair of upper and lower shears 7, 8. Further, at the welding position B, a welding torch 11 such as, for example, a laser welding torch is provided so as to be able to move up and down and move freely in the width direction of the steel strips 1 and 2. A welding torch 11 travels along an abutting line formed between the rear end portion 1a and the front end portion 2a, and laser welding is performed. On both sides of this welding torch 11, a leading side fixed clamp 12 and a trailing side fixed clamp 13 are provided on a common work table 14 so as to be able to move up and down. When the surfaces are butted, the rear end 1a and the tip 2a of the leading steel strip 1 and the trailing steel strip 2 are fixed. Further, the work table 14 is provided with a leading side electromagnetic chuck 15 and a trailing side electromagnetic chuck 16 on both sides of the welding torch 11, so that when butting, the leading side electromagnetic chuck 15 is used to first conduct the leading side electromagnetic chuck 15. When the rear end 1a of the steel strip 1 is fixed and magnetized and the leading end 2a of the trailing steel strip 2 is brought close to the magnetized rear end 1a, the trailing steel strip 2 is moved backward by the magnetized rear end 1a. Tip 2a of steel strip 2
are suctioned and matched securely.

As described above, the ends 1a and 2a of both steel strips 1 and 2 are abutted on the work table 14, and with the ends 1a and 2a abutted, the work table 14 is placed on the turning table 17 and the ends 1a and 2a of the steel strips 1 and 2 are abutted. The rotary table 17 is configured to be movable in parallel with the reference side surface of the work table 14, and the rotary table 17 can be freely rotated around the intersection of one reference side surface of the work table 14 and the travel line of the welding torch, that is, the pivot portion 48 shown in FIG. Configure.

That is, as shown in FIG. 2, at the welding position B, welding is carried out vertically along the longitudinal direction of the beam 18a of the gate-shaped frame 18 provided across the traveling path of the leading steel strip 1 and the trailing steel strip 2. Moving tracks 19a, 1 such as rails
9b, and these moving tracks 19a,
A welding torch 11 is provided movably along the frame 19b, and a laser beam optical path 21 is provided above the frame 18, which is extendable and retractable. A welding torch 11 is connected to the tip of this optical path 21, and a laser oscillator 22 is connected to the rear end of the optical path 21. Both steel strips 1 and 2 are connected to the welding torch 11 by the laser emitted from the laser oscillator 22. be welded.

Furthermore, when configuring both the leading side and trailing side fixed clamps 12 and 13 to be freely raised and lowered as described above, the lifting device is constructed in combination with the work table 14 and the rotating table 17 as follows.
This lifting device has both fixed clamp pieces 12, 13.
Both have the same structure, and for convenience of explanation, the elevating device for the fixed clamp piece 13 will be mainly explained.

Usually, inside the gate-shaped frame 18, as shown in FIG.
A cylinder 27 and its rod 28 are attached to the side of each support column 26, respectively. In both cylinders 27, the trailing side fixed clamp piece 13 is attached to the upper end of each rod 28, and the trailing side fixed clamp piece 13 is configured to be movable up and down by the pair of cylinders 27 and their rods 28.
Although the elevating device for the leading-side fixed clamp 12 is not shown, it similarly consists of a pair of supports, a cylinder, and a rod.

Further, a work table 14 is arranged inside the pair of pillars 26, and the work table 14 is arranged on the turning table 17 via a pair of linear motion bearing rails 29 and a pair of linear motion bearings 30. Therefore, the work table 14 moves parallel to the reference plane of the steel strips 1 and 2 on the turning table 17, and as described later, the groove line between the steel strips 1 and 2 can be aligned with the torch travel line. can. Further, in order to move the work table 14, a numerically controlled motor 31 is arranged on the turning table 17, and a ball screw 32 is connected to the numerically controlled motor 31.
and connect the tip of the ball screw 32 to the work table 14. The turning table 17 is configured to be able to turn freely at a turning portion 48 at the intersection of one reference side edge of the work table 14, that is, the side edge parallel to the center line of the running line and the torch running line, and this turning movement is achieved by, for example, a cylindrical bearing. 49, by a ball screw 50 and a numerically controlled motor 51. For example, a fixed table 52 is provided below the rotating table 17, a cylindrical bearing 49 is interposed between the fixed table 52 and the rotating table 17, a ball screw 50 is aligned with the cylindrical bearing 49, and the ball screw 50 is aligned with the cylindrical bearing 49. A numerically controlled motor 51 is connected to 50.

Next, while constructing the work table 14 and the turning table 17 at the welding position B as described above, both steel strips 1,
At least two optical magnifying devices 42 are used to optically magnify and observe the line formed by abutting the abutting surfaces 1c and 2c between the ends 1a and 2a of 2, that is, both ends of the abutting line. , 43,
These enlarging devices 42 and 43 are configured to be movable in the sheet width direction similarly to the welding torch 11.

That is, each of the optical magnifying devices 42, 43 has the same structure and consists of microscopes 42a, 43a and cameras 42b, 43b, and each of the magnifying devices 42, 43 having this structure is mounted on a movable saddle 42c, 43c. . Each of the movable saddles 42c and 43c needs to be constructed so that it can run in the width direction of the steel strips 1 and 2, but normally, as shown in FIG. , 43c, these moving tracks 1
9a and 19b.
Note that each of the movable saddles 42c and 43c can be driven independently without being associated with the welding torch 11, but as shown in FIG.
3c is constructed integrally with the welding torch 11 so that they can be moved in the sheet width direction by a ball screw 23a and a numerically controlled motor 24, and one movable saddle 42c is constructed by a ball screw 44 and a numerically controlled motor 45. It can be configured to be able to move independently in the board width direction.

Further, as described above, one side edge 1b, 2b of the steel strips 1, 2 is cut at the cutting position A, and one side edge 1b of both the steel strips 1, 2 is cut on the work table 14 at the welding position B. , 2b are aligned and brought into exact abutment. In this case, electromagnets can be used as shown in FIGS. 3a and 3b.

That is, in the third a and b, the symbol 36
indicates the cutting line of the upper and lower shears 7 and 8, 37 indicates the torch running line of the welding torch 11, the cutting line 36 and the torch running line 37 are perpendicular to the running line of the steel strip or the center line of the welding line, etc., and the welding cutting process is performed. It is fixed without moving inside. These cutting lines 36
Also, three alignment devices 38, 39, 40 are provided across the torch travel line 37, and the cutting position A
A hump roll 41 is provided between the welding position B and the welding position B so as to be movable up and down by a numerically controlled motor 41a, a bevel gear 41b, a ball screw 41c, and a bearing metal fitting 41d. Each alignment device 38, 3
9 and 40 have the same structure, and at least two reference magnet blocks 38a, 39a, 40a are provided parallel to the welding line center line (or the center line of the running line of both steel strips 1 and 2), and these reference magnet blocks Cutting position A and welding position B (or work table 14) are controlled by blocks 38a, 39a, and 40a.
constitutes one reference aspect of Furthermore, at least one moving magnet chuck 38b, 39 is provided between the reference magnet blocks 38a, 39a, 40a.
b, 40b are provided, and at the time of cutting or butting, the moving magnet chuck attracts the lower surface of the leading steel strip 1 or the trailing steel strip 2 to each reference magnet block 38.
I brought it to the a, 39a, and 40a sides, and each steel strip 1,
One side edge 1b, 2b of 2 is brought into contact with each other. In addition,
Each moving magnet chuck 38b, 39b, 40b and each reference magnet block 38a, 39a, 40a
is configured to be movable in the board width direction by cylinders 38c, 39c, and 40c.

Therefore, a method of welding after cutting the respective ends 1a and 2a of both the leading and trailing steel strips 1 and 2 according to the present invention in the welding apparatus having the above configuration will be explained as follows.

First, when cutting the rear end portion 1a of the preceding steel strip 1, the movable clamp 20 is opened at the welding position B and moved to the most upstream side, while at the cutting position A
Now, close the opening/closing table 34, and send the leading steel strip 1 by the pair of pinch rollers 3, 4 to the rear end 1a.
is stopped on the opening/closing table 34 as shown in FIG. At this time, the movable magnet chuck 39b of the aligning device 39 is energized, the reference magnet block 39a is energized, and the cylinder 39c is pressed against the reference side surface of the table at the cutting position A.

Next, the leading steel strip 1 is moved in the strip width direction by the moving magnet chuck 39b, and one side edge 1b is brought into contact with the reference magnet block 39a for automatic alignment (this state is shown in FIG. 3a). ), the electromagnetic chuck 9 on the shear outlet side is energized, the leading steel strip 1 is held by the movable clamp 20, and in some cases, the movable clamp 20 is driven with the electromagnetic chuck 9 energized. The cutting clamp 47 is moved by the hydraulic cylinder 46 to the downstream side by about 10 mm.
is lowered to hold down the rear end portion 1a of the preceding steel strip 1 from above.

Next, open the opening/closing table 34 and open the upper sear 7.
lower, cut the rear end 1a, raise the upper shear 7, close the opening/closing table 34, and open the hydraulic cylinder 4.
At 6, the cutting clamp 47 is opened, the reference magnet block 39a is demagnetized, and the cylinder 39c is moved back.

After cutting, the preceding steel strip 1 is moved downstream by the movable clamp 20, and the electromagnetic chuck 15 is energized at the welding position B.

In this state, the moving clamp 20 is driven by, for example, a numerically controlled motor, and the leading steel strip 1 is moved downstream by about 10 mm.

Next, the tip 2a of the trailing steel strip 2 is cut,
The tip portion 2 is fed by a pair of pinch rollers 3 and 4.
When a passes through the lower shear 8, that is, the cutting line 36, it stops (the trailing steel strip 2 in this state is shown by a dashed line in FIG. 3b), and the moving magnet chuck 38b of the aligning device 38 is energized. At the same time, the reference magnet block 38a is energized and pressed against the reference side surface of the table at the cutting position A, and as in the case of the leading steel strip 1, the trailing steel strip 2 is attracted by the moving magnet chuck 38b as shown in FIG. 3b. Then, one side edge 2b thereof is brought into contact with the reference magnet block 38a (the trailing steel strip 2 in this state is shown by a dotted line in FIG. 3b). Next, the electromagnetic chuck 10 is energized, the tip 2a is held by the cutting clamp 47, and in this state, the trailing steel strip 2 is cut by about 30 mm by the pinch rollers 3 and 4 (this amount is determined by the upper shear 7). This is the amount by which the trailing steel strip 2 is drawn in during cutting.) The steel strip 2 is fed in, the opening/closing table 34 is opened, and the upper shear 7 is lowered to cut.

Next, at the welding position B, the steel strips 1 and 2 are butted with the cut surfaces 1c and 2c as abutting surfaces. At this time, the pinch rollers 3 and 4 feed the leading end 2a of the trailing steel strip 2 onto the hump roller 41, and at this time, the hump roller 41 is raised to loop the leading end 2a. This height is set higher depending on the thickness of the plate, and the thinner the plate is. Further, the abutting surface 1c (that is, the cutting line 1c) of the rear end portion 1a of the preceding steel strip 1 coincides with the torch travel line 37 as described above, and while the electromagnetic chuck 15 is energized in this state, By means of a pair of pinch rollers 3 and 4, the tip end 2a of the trailing steel strip 2, in particular, the abutting surface 1c of the leading steel strip 1 is
Feed it until it hits.

Since the electromagnetic chuck 15 is energized at this time, a magnetic force is generated on the abutting surface 1c of the preceding steel strip 1, and the abutting surfaces 1c and 2c are attracted to each other, and even a thin material can be abutted over the entire width. Since the trailing steel strip 2 has a certain degree of freedom, the trailing steel strip 2 is butted along the leading steel strip 1,
The butt gap becomes zero. In addition, when the reference magnet block 40a of the alignment device 40 is excited and pressed by the cylinder 40c in a state where both the abutting surfaces 1c and 2c are attracted to each other in this way, both the abutting surfaces 1c and 2c are at the welding position B. The edges 1b and 2b can be moved in the width direction of the sheet while being pulled together, and then the leading end 2a of the trailing steel strip 2 is attracted by the electromagnetic chuck 16 on the work table 14, and both abutting surfaces are A line of abutment with substantially zero gap is formed between 1c and 2c.

Next, as described above, after butting the respective butting surfaces 1c and 2c of both steel strips 1 and 2 on the work table 14, it is checked whether or not this butting line accurately matches the torch travel line of the welding torch 11. Confirm by optically magnifying, and if there is even a slight error between the butt line and the torch travel line, correct it.

First, to perform confirmation and correction, the fixed clamps 12 and 13 on the work table 14 are lowered to an intermediate position. That is, it is necessary to bring the microscopes 42a and 43a of the two optical magnifying devices 42 and 43 closer to the two steel strips 1 and 2 of the target object, and for this purpose, both the fixing clamps 12 and 13 must be lowered, but this will be explained later. In order to move the work table 14 etc. for fine adjustment, both fixed clamps 1 are
2 and 13 are kept floating from the work table 14.

Next, the numerical control motor 45 is driven, and the microscope 42a moves one of the movable saddles 42c via the ball screw 44 to the center of the rotating section 48 of the rotating table 17. Furthermore, while the movable clamp 20 is released, the upper roller 3 of the pinch rollers 3 and 4 is released, and the aligning devices 39 and 40 are released.
The reference magnet blocks 39a and 40a are demagnetized by the cylinders 39c and 40c, and the work table 14 is demagnetized by the cylinders 39c and 40c.
to retreat from.

Next, the electromagnetic chucks 15 and 16 are energized, and both the leading and trailing steel strips 1 and 2 are connected to the work table 1.
4, drive the numerically controlled motor 31 to move the work table 14 parallel to the reference side surface of the steel strip via the ball screw 32, so that one end of the butt line magnified by the microscope 42a is in the field of view. Make sure it's in the center. That is, the image taken by the camera 42b is automatically processed, one end of the butt line is corrected by the image sensor so that it is on the torch traveling line 37, and the microscope 42a is retracted.

Next, the numerical control motor 24 is driven to move the other moving saddle 43c through the ball screw 23a.
is moved so that the microscope 43a and the camera 43b come to one end of the abutting line, that is, the line formed by abutting the respective abutting surfaces 1c and 2c of both steel strips 1 and 2. In this case as well, the image is automatically processed by the image sensor so that one end of the butt line magnified by the microscope 43a is placed in the center of the field of view, as in the above case, and at this time, the numerically controlled motor 51 is driven and the ball screen is The turning table 17 is turned around the turning part 48 via the bow 50, and the other end of the butt line is connected to the torch running line 37 of the welding torch 11.
match. Note that the microscope 43a is evacuated by the numerically controlled motor 24. Furthermore, welding is performed using fixed clamps 12 and 13 for both the leading and trailing steel strips 1,
Press 2 into the back bar across the butt line,
Laser welding is performed by moving the welding torch 11 in the width direction of the plates under welding conditions set based on the plate thickness, steel type, plate width, etc.

<Effects of the Invention> As explained in detail above, the present invention involves cutting the rear end of the leading steel strip and the leading end of the trailing steel strip, and then butting these cut surfaces together on a work table to form a butt line. Then, while magnifying and observing the intersection of one reference side surface of the work table and the torch running line using a microscope, move the work table in a direction parallel to that one reference side surface, that is, the running line of the steel strip. direction under numerical control so that one end of the butt line coincides with this intersection, while the other end of the butt line is magnified and observed using a microscope, while the work table is numerically controlled around the intersection. Swirl under the
The other end of the butt line is placed in the center of the field of view of this microscope, so that the butt line and the torch travel line are aligned.

When adjusted in this manner, the matching line is reliably matched with the torch travel line because the alignment is finely adjusted through image processing.

In addition, since movement of the work table and rotation of the turning table are performed using numerically controlled motors and ball screws, adjustments can be made in microns.In particular, the deviation between the butt line and the torch travel line can be adjusted by 40
The vertical misalignment between the two steel strips is less than 10 microns, and the gap at the butt line is less than 40 microns across the entire width, making it possible to laser weld ultra-thin wide steel strips of about 0.15 mm. .

[Brief explanation of the drawing]

FIG. 1 is a side view of a laser welding device as an example of a device for carrying out the method of the present invention, FIG. 2 is a front view showing a partial cross section taken in the direction of the arrow in FIG. 1, and FIGS. 3a and 3b are FIG. 2 is a plan view showing a state in which an end of a steel strip is cut in the laser welding apparatus shown in FIG. 1; Code 1... Leading steel strip, 1a... Rear end, 1b...
...Side edge, 1c...Abutment surface, 2...Trailing steel strip, 2
a...Tip portion, 2b...Side edge, 2c...Abutment surface, 3, 4...Pinch roller, 5...Cutting device,
6... Sukeyashia frame, 7, 8... Skeyah,
9...Electromagnetic chuck, 10...Electromagnetic chuck, 1
1... Welding torch, 12, 13... Fixed clamp, 14... Work table, 15, 16... Electromagnetic chuck, 17... Swivel table, 18... Frame, 19a, 19b... Moving track, 20... ...Moving clamp, 21...Laser beam optical path, 22...
Laser oscillator, 23a...Ball screw, 2
4... Numerical control motor, 25... Base, 26...
...Strut, 27...Cylinder, 28...Rod, 2
9...Bearing rail, 30...Bearing,
31... Numerical control motor, 32... Ball screw, 34... Opening/closing table, 35... Cylinder, 36... Cutting line, 37... Torch running line, 3
8, 39, 40... alignment device, 42, 43...
Optical magnifying device, 44...Ball screw, 4
5... Numerical control motor, 46... Hydraulic cylinder,
47... Cutting clamp, 48... Swivel part.

Claims (1)

[Claims] 1. After cutting the rear end of the leading steel strip and the leading end of the trailing steel strip, the cut surfaces are butted against each other on a work table to form a butt line, and a laser beam is applied along this butt line. When laser welding is performed by moving a welding torch, the microscope moves along a path that corresponds to the torch travel line at a point corresponding to the intersection of one reference side surface of the work table and the torch travel line of the laser welding torch. The work table is numerically controlled and moved in a direction parallel to one reference side surface thereof to align one end of the butt line with the intersection point, while observing under magnification. The work table is numerically controlled and rotated around a rotation center that coincides with the intersection point while the other end of the butt line is magnified and observed using the other microscope that moves along a path that coincides with the line. , aligning the other end of the matching line with the torch travel line by placing the other end of the matching line in the center of the scale of the field of view of the other microscope;
A laser welding method characterized in that the laser welding torch is then moved to carry out laser welding. 2. Laser welding in which the rear end of the leading steel strip and the tip of the trailing steel strip are cut, these cut surfaces are butted together on a work table, and a laser welding torch is run along this butt line to perform laser welding. The apparatus includes: a first numerically controlled motor that numerically controls and moves the work table in a direction parallel to one reference side surface of the work table; a second numerically controlled motor that numerically controls and turns the work table using the intersection with the running line as the center of rotation; an optical magnifying device capable of magnifying the other end of the abutment line to be observed based on a field of view scale and connected to the second numerically controlled motor; A laser welding apparatus characterized in that an optical magnifying device is provided so as to be reciprocatable along a path that coincides with the torch traveling line.