JP2021090987A - Laser welding method and laser welding device - Google Patents

Abstract

To provide a laser welding method and a laser welding device with which excessive melting of a filler wire can be avoided, and with which a filler wire can be stably melted always, when joining two metal plates of about 5 mm plate thickness by using laser light.SOLUTION: Provided is a laser welding method for joining two metal plates W and W together by using laser welding. In the laser welding method, when irradiating a laser light L along a gap Wa while a filler wire FW is fed from a front side toward a rear side in a welding advancing direction with respect to the gap Wa between the metal plates W and W, and while oscillating the laser light L so as to straddle the gap Wa, an oscillation optical path OT of the laser light L under oscillation operation at the time of passing the gap Wa has a protruding circular arc shape on the rear side in the welding advancing direction so as to surround a tip FWt of the filler wire FW in a meltable manner. If the tip FWt of the filler wire FW is displaced relative to the circular arc shaped oscillation optical path OT, an irradiation position of the laser light L is corrected by the displaced amount.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to, for example, a laser welding method and a laser welding apparatus used when joining metal plates having a plate thickness of about 5 mm by irradiation with a laser beam.

When metal plates having a thickness of about 5 mm are joined to each other as described above, a gap is inevitably generated between the metal plates. When metal plates having such a gap are joined by laser light, in order to eliminate this gap, for example, a laser welding device that oscillates the laser light while supplying a filler wire to the gap has been used. It has been adopted (see Patent Document 1).

That is, this laser welding device has an optical system that collects laser light from a laser light source on a metal plate and oscillates it so as to straddle a gap generated between the metal plates, and moves this optical system along the gap. It is provided with a moving mechanism for making the filler wire, a wire feeder for supplying the filler wire to the gap, and a wire supply control unit for calculating the supply position and the attitude of the filler wire to control the wire feeder.

At this time, the optical system includes a light receiving optical system that receives the return light of the laser light from the metal plate and measures the light intensity, and the wire supply control unit follows the oscillating operation of the change in the light intensity from the light receiving optical system. The supply position of the filler wire and its attitude are calculated.

That is, in this laser welding device, the position and orientation of the welded portion along the oscillate are calculated based on the change in the light intensity from the light receiving optical system, so that the wire feeder corresponds to the calculated position and orientation of the welded portion. By operating, the filler wire can be stably supplied to the welded portion position.

Japanese Unexamined Patent Publication No. 2016-043409

However, in most of the above-mentioned conventional laser welding devices, although the filler wire can be stably supplied to the welded portion position, the filler wire supplied from the front side to the rear side in the welding progress direction When the tip exceeds the position of the weld and enters the rear side in the welding progress direction, the tip of the filler wire is excessively melted before the wire supply control unit calculates the supply position and its attitude of the filler wire. There is a problem that welding defects may occur as a result of being separated from the molten pool, and solving this problem has become a conventional problem.

The present disclosure has been made to solve the above-mentioned conventional problems, and is a laser capable of avoiding excessive melting of filler wires when metal plates having a thickness of about 5 mm are joined by irradiation with a laser beam. It is an object of the present invention to provide a welding method and a laser welding apparatus.

The first aspect of the present disclosure is a laser welding method in which metal plates are joined by laser welding, and a filler wire is supplied from the front side to the rear side in the welding progress direction with respect to the gap between the metal plates. When irradiating the laser beam along the gap while oscillating the laser beam so as to straddle the gap, the oscillating optical path of the laser beam that operates oscillating when passing through the gap surrounds the tip of the filler wire. The structure is such that it has an arc shape that is convex to the rear side in the welding progress direction.
Further, in the second aspect of the present disclosure, when the tip of the filler wire is displaced with respect to the arcuate oscillating optical path, the irradiation position of the laser beam is corrected by the amount of the displacement.

On the other hand, the third aspect of the present disclosure is a laser welding apparatus for joining metal plates to each other by laser welding, in which a laser head that irradiates laser light between the metal plates and the laser light between the metal plates. A head drive mechanism that moves along the gap, an oscillating mechanism that oscillates the laser beam so as to straddle the gap, and a wire supply that supplies filler wires from the front side to the rear side in the welding progress direction with respect to the gap. The control unit includes a unit and a control unit that controls each operation of the laser head, the head drive mechanism, and the oscillating mechanism. The control unit has an oscillating optical path of the oscillating laser beam when passing through the gap of the filler wire. The oscillating mechanism is controlled so as to form a convex arc shape on the rear side in the welding progress direction so as to surround the tip.
Further, a fourth aspect of the present disclosure has a wire detection unit for detecting the supply status of the filler wire, and the control unit has the tip of the filler wire displaced with respect to the arcuate oscillating optical path. When the wire detection unit detects the above, the oscillating mechanism is controlled so as to correct the irradiation position of the laser beam by the amount of the deviation.

In the laser welding method and the laser welding apparatus according to the present disclosure, the thickness of the metal plate to be joined by laser welding is not particularly limited. For example, a metal plate of 3 to 6 mm called a middle plate is particularly targeted.

Further, in the laser welding method and the laser welding apparatus according to the present disclosure, a YAG laser, a semiconductor laser, or a fiber laser is generally used as the laser, but the laser is not limited to these.

Further, the laser welding method and the laser welding apparatus according to the present disclosure can be used for abutting and joining metal plates to each other, and the laser welding method and the laser welding apparatus according to the present disclosure can be used for fillet welding between metal plates. Can also be applied.

According to the laser welding method and the laser welding apparatus according to the present disclosure, it is very excellent that excessive melting of the filler wire can be avoided when metal plates having a plate thickness of about 5 mm are joined by irradiation with a laser beam. The effect is brought about.

It is a schematic explanatory drawing which shows the laser welding apparatus used in the laser welding method which concerns on one Embodiment of this disclosure. 1 is a partially enlarged cross-sectional explanatory view (a) and a partially enlarged plane explanatory view (b) showing a positional relationship when the distance between the laser beam oscillated by the laser welding apparatus of FIG. 1 and the upwardly warped tip of the filler wire is short. .. 2 is a partially enlarged cross-sectional explanatory view (a) and a partially enlarged plane explanatory view (b) showing a positional relationship with respect to an upwardly warped tip of the filler wire after correcting the irradiation position of the laser beam in the state of FIG. 1 is a partially enlarged cross-sectional explanatory view (a) and a partially enlarged plane explanatory view (b) showing a positional relationship when the distance between the laser beam oscillated by the laser welding apparatus of FIG. 1 and the downwardly warped tip of the filler wire is short. .. It is a partially enlarged cross-sectional explanatory view (a) and a partially enlarged plane explanatory view (b) which show the positional relationship with respect to the downwardly warped tip of the filler wire after correcting the irradiation position of the laser beam in the state of FIG.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
FIG. 1 shows a laser welding apparatus according to an embodiment of the present disclosure, and in the present embodiment, a case where the laser welding apparatus according to the present disclosure is used for butt-joining metal plates will be described as an example. ..

As schematically shown in FIG. 1, this laser welding apparatus 1 butt-bonds metal plates W and W to each other by laser welding, and is a laser oscillator 2 and a laser beam supplied from the laser oscillator 2. A laser head 4 that collects light by an optical system 3 with a built-in L and irradiates it between the metal plates W, W, an optical fiber 5 that guides a laser beam L from a laser oscillator 2 to a laser head 4, and a metal laser head 4. The head drive mechanism 6 that moves along the gap Wa generated between the plates W and W and the laser beam L that reciprocates so as to straddle the gap Wa, that is, the oscillate that oscillates the laser beam L across the gap Wa. The mechanism 8, the wire supply unit 11 that supplies the filler wire FW from the front side to the rear side in the welding progress direction (direction from the upper right to the lower left in FIG. 1) with respect to the gap Wa, and the supply status of the filler wire FW. It includes a camera (wire detection unit) 12 for detection, and a control unit 10 for controlling each operation of the laser head 4, the head drive mechanism 6, and the oscillating mechanism 8.

The head drive mechanism 6 includes a rail 6a arranged along a gap Wa between the metal plates W and W, and a slider 6b that reciprocates on the rail 6a. In this case, the laser head 4 is fixed to the slider 6b so as to match the laser beam irradiation direction so as to straddle the gap Wa.

The oscillating mechanism 8 is held in a case 9 attached to a slider 6b of the head drive mechanism 6 via a support base 7, and rotates around a horizontal axis to transmit a laser beam L from the laser head 4 to a metal plate W. , A scanner mirror 8a that reflects toward W and a mirror motor 8b that rotates the scanner mirror 8a within a predetermined range are provided.

At this time, the oscillating mechanism 8 includes a gimbal 8c that rotates around a vertical axis and a gimbal motor 8d that rotates the gimbal 8c within a predetermined range, and the scanner mirror 8a and the mirror motor 8b are gimbaled. By supporting it with 8c, the scanner mirror 8a can be rotated with two degrees of freedom.

In this embodiment, as shown in the enlarged circle of FIG. 1, the control unit 10 has an arc shape that is convex to the rear side in the welding progress direction of the oscillating optical path OT when the oscillating laser beam L passes through the gap Wa. The mirror motor 8b and the gimbal motor 8d of the oscillating mechanism 8 are controlled so as to be.

More specifically, the control unit 10 sets the oscillating optical path OT so as to surround the tip FWt of the filler wire FW, and controls the laser beam L to move in a meltable manner in the vicinity of the tip FWt of the filler wire FW. By doing so, the filler wire FW is stably melted.

Further, when the camera 12 detects that the tip FWt of the filler wire FW deviates from a preset position with respect to the arcuate oscillating optical path OT, the control unit 10 irradiates the laser beam L by the amount of the deviation. The mirror motor 8b and the gimbal motor 8d of the oscillating mechanism 8 are controlled in order to correct the position.

That is, as shown in FIGS. 2A and 2B, the control unit 10 of the oscillating mechanism 8 when the tip FWt of the upward warp of the filler wire FW penetrates deeply inside the arcuate oscillating optical path OT. A command is issued to the mirror motor 8b and the gimbal motor 8d to move the arc-shaped oscillating optical path OT in the direction of the illustrated arrow (moving the irradiation position of the laser beam L), and FIGS. ), The tip FWt of the filler wire FW is controlled to be located substantially at the center of the arcuate oscillating optical path OT.

Similarly, as shown in FIGS. 4A and 4B, the control unit 10 mirrors the oscillating mechanism 8 when the tip FWt of the downward warp of the filler wire FW deviates from the arcuate oscillating optical path OT. A command is issued to the motor 8b for the gimbal and the motor 8d for the gimbal, and the arcuate oscillating optical path OT is moved in the direction of the arrow in the drawing (the irradiation position of the laser beam L is moved), and FIGS. As shown in the above, the tip FWt of the filler wire FW is controlled to be located substantially at the center of the arcuate oscillating optical path OT.

When joining the metal plates W and W using the laser welding apparatus 1 configured in this way, first, a tab plate T is temporarily attached between both ends of the metal plates W and W.

After that, when the laser welding apparatus 1 is started, the laser oscillator 2 starts supplying the laser beam L to the laser head 4, and the laser head 4 irradiates the laser beam L focused by the optical system 3 with the metal plate W. It will start towards the W.

At the same time, the head drive mechanism 6 and the oscillating mechanism 8 each start operating, whereby the laser beam L is oscillated so as to straddle the gap Wa generated between the metal plates W and W along the gap Wa. Moving. Then, the wire supply unit 11 operates in accordance with the movement of the laser beam L, and the supply of the filler wire FW to the gap Wa is started from the front side to the rear side in the welding progress direction.

In this laser welding device 1, when the oscillating laser beam L passes through the gap Wa, the mirror motor 8b and the gimbal motor 8d of the oscillating mechanism 8 operate to form a circular convex rearward in the welding progress direction. The laser beam L moves along the oscillating optical path OT set to form an arc (surrounding the tip FWt of the filler wire FW). That is, the laser beam L moves so as to be meltable in the vicinity of the tip FWt of the filler wire FW.

Therefore, in this laser welding apparatus 1, since the laser beam L does not directly hit the tip FWt of the filler wire FW, it is possible to prevent the filler wire FW from being unexpectedly excessively melted. That is, the tip of the filler wire is not excessively melted and separated from the molten pool, and the occurrence of welding defects is avoided.

In addition, in the laser welding apparatus 1, when the camera 12 detects that the tip FWt of the filler wire FW deviates from a preset position with respect to the arcuate oscillating optical path OT, a command from the control unit 10 is used. The mirror motor 8b and the gimbal motor 8d of the oscillating mechanism 8 operate, and the irradiation position of the laser beam L is corrected by the amount of deviation.

That is, since the filler wire FW can always be stably melted in response to the misalignment of the tip FWt of the filler wire FW, the occurrence of welding defects such as unbonded can be suppressed to a small extent.

In the above-described embodiment, the case where the laser welding method and the laser welding apparatus according to the present disclosure are the laser welding method and the laser welding apparatus in which the metal plates W and W are butted and joined to each other is shown, but the present invention is limited to this. However, it is naturally possible to apply the laser welding method and the laser welding apparatus according to the present disclosure to fillet welding between metal plates.

The configuration of the laser welding method and the laser welding apparatus according to the present disclosure is not limited to the above-described embodiment, and can be variously modified without departing from the spirit of the invention.

1 Laser welding device 4 Laser head 6 Head drive mechanism 8 Oscillating mechanism 10 Control unit 11 Wire supply unit 12 Camera (wire detection unit)
FW Filler wire FWt Tip of filler wire L Laser beam OT Oscillate optical path W Metal plate Wa Gap

Claims (4)

This is a laser welding method in which metal plates are joined by laser welding.
When irradiating the laser beam along the gap while supplying the filler wire from the front side to the rear side in the welding progress direction with respect to the gap between the metal plates and oscillating the laser beam so as to straddle the gap. ,
A laser welding method in which an oscillating optical path of the laser beam that operates oscillating when passing through the gap is formed into an arc shape that is convex to the rear side in the welding advancing direction so as to surround the tip of the filler wire. The laser welding method according to claim 1, wherein when the tip of the filler wire is displaced with respect to the arcuate oscillating optical path, the irradiation position of the laser beam is corrected by the amount of the displacement. A laser welding device that joins metal plates by laser welding.
A laser head that irradiates laser light between the metal plates and
A head drive mechanism that moves the laser beam along the gap between the metal plates, and
An oscillating mechanism that oscillates the laser beam so as to straddle the gap,
A wire supply unit that supplies filler wires from the front side to the rear side in the welding progress direction with respect to the gap.
A control unit that controls each operation of the laser head, the head drive mechanism, and the oscillating mechanism is provided.
The control unit controls the oscillating mechanism so that the oscillating optical path of the oscillating laser beam when passing through the gap becomes a convex arc shape on the rear side in the welding progress direction so as to surround the tip of the filler wire. Laser welding equipment. The control unit has a wire detection unit that detects the supply status of the filler wire, and the control unit detects when the tip of the filler wire is displaced with respect to the arcuate oscillating optical path. The laser welding apparatus according to claim 3, wherein the oscillating mechanism is controlled so as to correct the irradiation position of the laser beam by the amount of the deviation.

Images