JP2703450B2 - Setting method of laser beam irradiation position in laser welding - 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 setting a laser beam irradiation position in laser welding when butt welding metal strips.

[0002]

2. Description of the Related Art When butt welding metal strips such as stainless steel strips and silicon steel strips, laser welding, which can perform welding with low heat input and high energy density, has been frequently used as a welding method. Therefore, a conventional laser beam welding machine for metal strips will be described with reference to schematic diagrams shown in FIGS.

In FIG. 3 showing a laser beam welding machine,
1 is a laser beam oscillator, 2 is a laser beam transmission system having a mirror, a beam duct, etc. for transmitting a laser beam from the laser beam oscillator 1, 3 is a laser beam from the laser beam transmission system 2 irradiating a laser beam Strip S
₁ and the trailing strip S ₂ is a laser torch for butt welding. 4 is an inlet clamp, 5 is an outlet clamp,
6 is a double cut shear, each of which is a base 10
It is provided above. As shown in FIG. 4, the laser torch 3 includes a plurality of mirrors 31 for changing the traveling direction of the laser beam 7 therein, and a condensing mirror for condensing the laser beam 7 guided by the plurality of mirrors 31. 32.

Next, the operation will be described. Preceding when welding a metal strip S ₂ of the trailing and the metal strip S ₁ is to, first, prior metals the trailing end of the strip S ₁ by the egress clamp 4, entry side clamp the leading end of the trailing metal strip S ₂ Clamp each at 4. Next, the double cut shear 6 is advanced to the welding line, thereby cutting each end, and after cutting, the double cut shear 6 is retracted off-line. Thereafter, in a state in which the trailing metal strip S ₂ is clamped by the inlet side clamp 4, the trailing metal strip S ₂ the exit side clamp 5 preceding metal strip tip of the trailing metal strip S ₂ is moved to the side S _{1. While} the laser torch 3 is traveling along the butt line 8 under this condition, the laser beam 7 from the focusing mirror 32 is irradiated to the butt line 8 as shown in FIG. ,
A weld bead 9 is made.

In laser beam welding, generally, the irradiation position of the laser beam 7 on the metal strips S ₁ and S ₂ is extremely important for welding control. The irradiation position includes the position in the height direction and the position in the horizontal plane. There is. Among these, the position in the height direction refers to the focal position of the focused laser beam 7, and various methods of controlling the position in the height direction have already been proposed in Japanese Patent Publication No. 60-33593. . On the other hand, the position in the horizontal plane is
Of the laser beam 7 with respect to the metal strips S ₁ ,
Without the proper position over the S ₂ overall width must not, focus diameter of the laser beam 7 condensed varies depending its output, generally about 0.1 to 0.4 mm, combined that position Accuracy is required.

In order to confirm the irradiation position of the laser beam 7 in the horizontal plane, the following method is usually employed. That is, the irradiation position of the laser beam 7 is changed by trial and error in the direction perpendicular to the butt line 8 of the metal strips S ₁ and S ₂ , laser welding is performed in advance, and this weld bead is subjected to an Erichsen test or the like. A mechanical test was performed to adjust the position of the laser torch 3 to the irradiation position where the maximum intensity was obtained. FIG. 5 is an example showing the test results. The horizontal axis is the irradiation position of the laser beam 7, the irradiation position before the start of the check is a reference point (zero point), the vertical axis is the Erichsen test value, and the maximum intensity is 1 point. 0.0. Since the irradiation position in this figure is within the range where the maximum intensity is obtained, the current irradiation position is sufficient, but it is further increased by 0.3% to the plus side.
It can be seen that it is better to move the laser torch 3 by + (− 0.2)｝ / 2 = 0.05 mm.

In addition to the above method, a laser beam 7 is irradiated in a spot manner, and in this state, that is, in a state where the metal strips S ₁ and S ₂ are clamped, the molten state in the spot irradiation part on the front and back surfaces is checked. There is also a method of confirming the irradiation position by observing.

[0008]

However, in the former method of setting the irradiation position by the former mechanical test, there is a problem that setting the irradiation position requires much time. Also, in the latter method of setting the irradiation position by spot irradiation, the setting time can be shortened compared to the former method, but when observing the molten state, the clamps 4 and 5 restrain the metal strips S ₁ and S ₂ . If you release the state,
Since the metal strips S ₁ and S ₂ are separated from each other, the observation is performed in a clamped state, that is, an operation in a laser welding machine, and there is a problem in workability and safety. Further, in the latter method, when it is necessary to collect a sample, the sample cannot be collected and the metal strip S
_1, guarantee that even a proper irradiation position at one point in the width direction of S ₂ is the proper position over the whole width had another problem that can not be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a method for setting a laser beam irradiation position in laser welding, which can easily and surely set a laser beam irradiation position. And

[0010]

According to the present invention, there is provided a method for setting a laser beam irradiation position in laser welding, wherein the laser beam welding is performed when the rear end of the preceding metal strip and the front end of the succeeding metal strip are respectively butted. After forming a weld bead on each of the metal strips by linearly running the laser beam so as to obliquely cross at least two locations on the butt line of the metal strip, the weld bead from the laser beam irradiation start position to the butt line was measured. The position of the butting line of each metal strip is confirmed based on the ratio between the obtained travel distance and the travel distance obtained by measuring the welding bead from the laser beam irradiation start position to the laser beam irradiation end position. Is corrected.

[0011]

According to the present invention, when the rear end of the preceding metal strip and the front end of the succeeding metal strip are respectively butted and laser beam welded, they are obliquely crossed at at least two places on the butting line of each metal strip. A laser beam travels straight to form a weld bead on each metal strip, and the laser beam travel distance obtained by measuring the weld bead from the beam irradiation start position to the butt line and the beam irradiation end position from the beam irradiation start position Set the laser beam irradiation position by checking the position of the butting line of each metal strip based on the ratio of the laser beam travel distance obtained by measuring the welding bead up to and correcting the laser beam irradiation position can do.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. FIG. 1 is a plan view showing one embodiment of a method for setting a laser beam irradiation position according to the present invention.
FIG. 3 is a principle diagram of a method for setting a laser beam irradiation position according to the present invention.

When the method of setting the laser beam irradiation position in the present embodiment is performed, first, the rear end of the preceding metal strip S1 is _{first set} using the laser welding machine shown in FIG. The exit side clamp 4 clamps the leading end of the subsequent metal strip S ₂ with the entry side clamp 4.
Next, the double cut shear 6 is advanced to the line, thereby cutting each end, and after cutting, the double cut shear 6 is retracted off-line. Thereafter, as shown in FIG. 1, matching the preceding metal strip S ₁ of the rear end and the trailing metal strip S ₂ tip, respectively.

[0014] Then, after setting the laser beam irradiation starting position of the laser torch 3 to the side edge vicinity of the trailing metal strip S ₂ tip, the metal strip S _1, S ₂ of the butt line 8
Each metal strip S ₁ a laser beam 7 by linear travel so as to cross over diagonally, S ₂ a weld bead W ₁ formed in each metal strip S ₁ on the butt line 8 along with this, S ₂ welded to make a binding point P ₁ of both of them in. Subsequently, moving the laser beam irradiation end position in the metal strip S ₁ of the previous weld bead W ₁ forming a laser torch 3 in the width direction. Thereafter, the position after the movement is set as the laser beam irradiation start position, and the laser beam 7 is inclined obliquely across the butting line 8 of the metal strips S ₁ and S _{2 to} the laser beam irradiation end position in the opposite direction. weld bead W ₂ and form a bond point P _2, further forms a bond point P ₃ and the weld bead W ₃ in the same manner. After forming the weld beads W ₁ , W ₂ , and W ₃ at three locations in this manner, the portions are cut out by the double cut shutter 6 and taken out to confirm the irradiation position of the laser beam 7. On this occasion,
The cut-out metal strips S ₁ and S ₂ are connected at the connecting points P ₁ , P ₂ and P ₃ , respectively, and are not separated.
The laser beam irradiation position can be easily and reliably confirmed.

Next, a method for confirming the optimum irradiation position of the laser beam 7 will be described with reference to FIG. To do this, first, a laser beam travel distance A ₁ and the laser beam irradiation starting position of the welding bead W ₁ of the laser beam 7 obtained by measuring the distance from the irradiation start position to butt line 8 to the laser beam irradiation end position Of the laser beam 7 obtained by measuring the welding bead W ₁ of the laser beam 7 to the traveling distance A ₁ /
Based on A, the position of the butting line 8 can be confirmed from the laser beam irradiation start position of the butting line 8 of each of the metal strips S ₁ and S ₂ . That is, in this figure, the amount of movement of the running direction of the metal strip torch to X 3 (X direction), the if the movement amount in the width direction of the metal strip (Y direction) Y, the weld bead W ₁ bead The length A can be obtained by linearly interpolating the laser torch 3 in the X and Y directions. The distance X direction X ₁ from the laser beam irradiation starting position to butt line 8, welded to A ₁ from the laser beam irradiation starting position bead W ₁ coupling point P ₁ by
Linear distance to the point of attachment of A ₂ by the welding bead W ₁ P ₁
From the laser beam irradiation start position to the abutting line 8, the distance X _{1 in the} X direction from the laser beam irradiation start position to the butt line 8 can be obtained from the following equation by measuring the linear distances A ₁ and A _2. From this calculation result, the distance in the X direction from the laser beam irradiation start position to the butting line 8 can be accurately obtained. X ₁ = X × {A ₁ / (A ₁ + A ₂ )} = X × (A ₁ / A)

Similarly, for the other two weld beads W ₂ and W ₃ , whether the amount of movement of the beam torch 3 during welding matches the butt line 8 of each of the metal strips S ₁ and S _2. Can be confirmed. If they do not match, the laser torch 3 is corrected so that the positions of the distances X ₁ , X ₂ , X ₃ obtained from the respective weld beads W ₁ , W ₂ , W ₃ are passed at the time of welding. Can be prevented.

It should be noted that the present invention is not limited to the above-described embodiment at all. When the rear end of the preceding metal strip and the front end of the following metal strip are respectively butted and laser beam-welded, each of the above-mentioned metal strips is welded. After forming a weld bead on each metal strip by linearly running a laser beam so as to obliquely cross at least two locations on the butt line, it is obtained by measuring the weld bead from the laser beam irradiation start position to the butt line. Based on the ratio of the travel distance and the travel distance obtained by measuring the welding bead from the laser beam irradiation start position to the laser beam irradiation end position, the position of the butting line of each metal strip is confirmed and the laser beam irradiation position is determined. Any method for compensating is included in the present invention.

[0018]

As described above, according to the method for setting a laser beam irradiation position in laser welding of the present invention,
By calculating the ratio of the weld bead length, which is obtained by irradiating the laser beam obliquely to the butt line,
There is an effect that the irradiation position of the laser beam can be easily and reliably set.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a method for setting a laser beam irradiation position according to the present invention.

FIG. 2 is an explanatory diagram illustrating the principle of a method for setting a laser beam irradiation position according to the present invention.

FIG. 3 is a perspective view schematically showing a conventional laser welding machine.

FIG. 4 is a perspective view schematically showing a laser torch of the laser welding machine shown in FIG. 3;

FIG. 5 is a graph showing an example of a relationship between a laser beam irradiation position and an Erichsen test value in a conventional method of setting a laser beam irradiation position.

[Explanation of symbols]

3 Laser Torch 7 Laser Beam 8 Butt Line A Weld Bead Length A ₁ Weld Bead Length from Laser Beam Irradiation Start Position to Butt Line S ₁ Lead Metal Strip S ₂ Trailing Metal Strip W ₁ Weld Bead X _{1 From} Laser Beam Irradiation Start Position Distance to butt line

Claims (1)

(57) [Claims] When a laser beam is welded by abutting a rear end of a preceding metal strip and a front end of a following metal strip, the laser beam is obliquely crossed at least two locations on a joining line of the metal strips. After forming a weld bead on each of the above metal strips by running straight, the travel distance obtained by measuring the weld bead from the laser beam irradiation start position to the butt line and the laser beam irradiation start position to the laser beam irradiation end position are obtained. The position of the butt line of each of the metal strips is confirmed based on the ratio to the travel distance obtained by measuring the welding bead, and the irradiation position of the laser beam is corrected by the laser beam irradiation position. Setting method.