JP2011050997A - Laser beam welding apparatus and laser beam welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam welding apparatus and a laser beam welding method which feed a filler wire to an adequate position in a molten pool, stabilize welding and perform the excellent laser beam welding of two metal plates even if the inner shape of the molten pool is changed when performing the laser beam welding of two vertically superposed metal plates while feeding the filler wire. <P>SOLUTION: When performing the laser beam welding of the two vertically superposed metal plates W1, W2 while feeding the filler wire X, upper and lower surfaces of a molten pool are imaged; the inner shape of the molten pool is estimated based on the imaged upper and lower surface shapes of the molten pool, and the advancing position and the advancing angle of the filler wire X with respect to the molten pool are adjusted based on the estimated inner shape of the molten pool. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laser welding apparatus and a laser welding method for laser welding two metal plates that are stacked one above the other while supplying filler wires.

  In recent years, laser welding is being used as a method for welding two metal plates stacked one above the other. This laser welding is performed by moving the laser light with respect to the two metal plates along a predetermined welding path while irradiating laser light toward the upper metal plate surface of the two metal plates. Two metal plates are melted to form a linear weld bead.

  Also, not only the metal plate but also the filler wire is melted, that is, melted by laser welding the two metal plates that are stacked one above the other while supplying the filler wire to the irradiated site that is irradiated with laser light. It is also known to connect two metal plates by increasing the metal.

  Regarding the supply of filler wire in this laser welding, the two metal plates stacked one above the other are not laser welded. For example, Patent Document 1 discloses a combined welding that combines laser welding and MIG welding. The weld pool formed on the work piece during welding is imaged, the distance from the laser beam irradiation point to the outline of the weld pool is determined based on the captured image, and the laser beam irradiation point and filler are calculated based on the calculated distance. Changing the relative position of the wire feed nozzle is disclosed.

  Further, for example, in Patent Document 2, the tip of a filler wire is imaged by an imaging means, and this imaging signal is subjected to image processing to detect a deviation in the amount and direction of delivery of the filler wire. It is disclosed that control is performed so as to be within an allowable range from the irradiation site.

  Further, for example, in Patent Document 3, an auxiliary beam obtained by deflecting a part of a laser used for welding is irradiated onto a filler wire, the irradiated portion is imaged with a camera, and the position of the filler wire is calculated from the captured image. It is disclosed that when the calculated position is outside the allowable range, the filler wire is moved and adjusted within the allowable range.

JP 2003-181664 A JP 2001-179471 A Japanese Patent Laid-Open No. 2003-211274

  By the way, when laser welding two metal plates stacked on top and bottom while supplying filler wire to the irradiated site irradiated with laser light, the metal plate and filler wire are melted by laser light, Energy may be consumed for melting the filler wire, and the metal plate may not be sufficiently melted.

  In contrast, by irradiating laser light toward the upper metal plate surface of the two metal plates, the metal plate is melted by the laser light to form a molten pool in which the molten metal is stored. By supplying the filler wire to the molten pool from the rear side in the welding direction with respect to the laser beam, the energy of the laser beam can be used for melting the metal plate without being consumed for melting the filler wire. Conceivable.

  In that case, the opposing surfaces of the two metal plates are generally not completely flat, and a gap is formed between the two metal plates. Therefore, in order to promote downward dripping of the molten metal, It is considered desirable to allow the filler wire supplied to the pond to enter a predetermined depth in the molten pool.

  However, when the filler wire enters the molten pool and is supplied to the molten pool, the shape of the molten pool changes during laser welding depending on various conditions such as the size of the gap formed between the two metal plates. In some cases, the filler wire may come into contact with a non-molten metal plate or welded portion that forms the outer peripheral surface of the molten pool, or may enter a keyhole formed in the molten pool by laser light.

  When the filler wire comes into contact with a non-molten metal plate or welded part, the filler wire is caught or bent, and the wire supply state becomes unstable and welding becomes unstable. When entering the formed keyhole, the filler wire is melted by the laser beam, the wire supply state is not constant, and welding becomes unstable.

  Therefore, the present invention stabilizes the welding by supplying the filler wire to a suitable position in the molten pool when laser welding the two metal plates stacked one above the other while supplying the filler wire. It is a basic object to provide a laser welding apparatus and a laser welding method capable of satisfactorily laser welding two metal plates.

  For this reason, the invention according to claim 1 of the present application irradiates the laser beam toward the upper metal plate surface of the two metal plates stacked one above the other along the predetermined welding path. The two metal plates are moved relative to the two metal plates, and the two metal plates are melted by laser light to store the molten metal in the molten pool from the upper surface of the upper metal plate to the lower metal plate. A laser welding apparatus for forming a filler wire to the molten pool from the rear side in the welding progress direction with respect to the laser beam, and laser welding two metal plates while supplying the filler wire, Wire supply adjusting means for adjusting the entry position and angle of the filler wire with respect to the molten pool, first imaging means for imaging the upper surface of the molten pool, and first imaging means for imaging the lower surface of the molten pool The inner shape of the molten pool based on the upper surface shape of the molten pool imaged by the first imaging means and the lower surface shape of the molten pool imaged by the second imaging means. A molten pool shape estimating means for estimating, the wire supply adjusting means, based on the internal shape of the molten pool estimated by the molten pool shape estimating means, and the position of the filler wire entering the molten pool and The approach angle is adjusted.

  The invention according to claim 2 of the present application is the laser welding apparatus according to claim 1, wherein the molten pool shape estimation means is a welding progress of the upper surface shape of the molten pool imaged by the first imaging means. Based on the direction rear end position and the welding progress direction rear end position of the lower surface shape of the molten pool imaged by the second imaging means, the shape of the welding progress direction rear end side inside the molten pool is estimated. The wire supply adjusting means has a welding progress direction inside the molten pool in which an extension line of the filler wire that enters the molten pool at a predetermined entry position at a predetermined entry angle is estimated by the molten pool shape estimating means. Adjusting the entry position and the entry angle of the filler wire with respect to the molten pool so as not to intersect with the portion corresponding to the upper metal plate in the shape of the rear end side A.

  Further, the invention according to claim 3 of the present application is the laser welding apparatus according to claim 1 or 2, wherein the molten pool shape estimating means is an upper surface of the molten pool imaged by the first imaging means. A shape that linearly connects the rear end position of the welding progress direction of the shape and the rear end position of the weld progress direction of the bottom surface of the molten pool imaged by the second imaging means is the rear of the welding progress direction inside the weld pool. It is estimated that the shape is the end side.

  Still further, an invention according to claim 4 of the present application is the laser welding apparatus according to any one of claims 1 to 3, wherein the molten pool shape estimation means is imaged by the first imaging means. Based on the upper surface shape of the molten pool and the lower surface shape of the molten pool imaged by the second imaging means, the shape of the keyhole formed in the molten pool by the laser light is estimated, and the wire The supply adjusting means is configured such that an extension line of the filler wire that enters the molten pool at a predetermined entry position at a predetermined entry angle is an upper metal of the keyhole shape estimated by the molten pool shape estimating means. The entry position and the entry angle of the filler wire with respect to the molten pool are adjusted so as not to intersect with the portion corresponding to the plate.

  Furthermore, in the invention according to claim 5 of the present application, the laser beam is irradiated along the predetermined welding path while irradiating the laser beam toward the upper metal plate surface of the two metal plates stacked one above the other. The two metal plates are moved relative to the two metal plates, and the two metal plates are melted by laser light to store the molten metal in the molten pool from the upper surface of the upper metal plate to the lower metal plate. A laser welding method in which the filler wire is supplied to the molten pool from the rear side in the welding progress direction with respect to the laser beam, and the two metal plates are laser welded while supplying the filler wire, The upper surface of the molten pool and the lower surface of the molten pool were respectively imaged, and based on the imaged upper surface shape of the molten pool and the lower surface shape of the molten pool, the internal shape of the molten pool was estimated and estimated in front Based on the internal shape of the molten pool, and to adjust the entry position and the entry angle of the filler wire relative to the molten pool, it is obtained by it said.

  According to the invention of claim 1 of the present application, the filler wire is placed from the rear side in the welding progress direction with respect to the laser beam into the molten pool formed by the laser beam from the upper surface of the upper metal plate to the lower surface of the lower metal plate. When supplying, the internal shape of the molten pool is estimated based on the upper surface shape of the molten pool imaged by the first imaging means and the lower surface shape of the molten pool imaged by the second imaging means, and this estimated Because the filler wire entry position and entry angle are adjusted based on the internal shape of the molten pool, the filler wire must be brought into contact with a non-molten metal plate or welded part or placed in a keyhole. The filler wire can be supplied to a suitable position in the molten pool, the wire supply state is made substantially constant to stabilize the welding, and the two metal plates are well laser welded. It can be. Even when the internal shape of the molten pool has changed, such as when the size of the gap formed between the two metal plates has changed, the filler wire is preferably used in the molten pool according to the estimated internal shape of the molten pool. The effect can be effectively obtained.

  Further, according to the invention according to claim 2 of the present application, the rear end position of the welding progress direction rear end position of the upper surface shape of the molten pool imaged by the first imaging means and the lower surface shape of the molten pool imaged by the second imaging means. The shape of the rear end side of the weld progress direction inside the weld pool is estimated based on the position of the rear end of the weld progress direction, and the extension line of the filler wire entering the weld pool is the estimated weld progress direction inside the weld pool. Since the entry position and the entry angle of the filler wire with respect to the molten pool are adjusted so as not to intersect with the portion corresponding to the upper metal plate in the shape on the rear end side, the effect can be realized more specifically. . The filler wire entry position and entry angle are adjusted so that the filler wire extension line does not intersect the portion corresponding to the upper metal plate in the shape of the weld welding direction rear end side in the molten pool. The filler wire that enters the molten pool is easily melted as the depth of penetration increases, and the filler wire is melted in the portion other than the portion corresponding to the upper metal plate of the molten pool, and the filler wire is not melted. It is because it can avoid contacting with the metal plate in a state.

  Further, according to the invention according to claim 3 of the present application, the rear end position of the welding progress direction rear end position of the upper surface shape of the molten pool imaged by the first imaging means and the lower surface shape of the molten pool imaged by the second imaging means. Since the shape that linearly connects the rear end position in the welding progress direction is estimated to be the shape on the rear end side in the welding progress direction inside the molten pool, the above-described effects can be effectively achieved.

  Still further, according to the invention of claim 4 of the present application, the keyhole is based on the upper surface shape of the molten pool imaged by the first imaging means and the lower surface shape of the molten pool imaged by the second imaging means. The filler wire entry position with respect to the molten pool so that the extension of the filler wire entering the molten pool does not intersect the portion corresponding to the upper metal plate in the estimated keyhole shape. Since the approach angle is adjusted, the effect can be realized more specifically. The filler wire entry position and entry angle were adjusted so that the filler wire extension line did not intersect the portion of the estimated keyhole shape corresponding to the upper metal plate. The filler wire entering the pond is more likely to be melted as the depth of penetration increases, and it can be avoided that the filler wire is melted in the portion other than the portion corresponding to the upper metal plate of the molten pool and the filler wire enters the keyhole. is there.

  Furthermore, according to the method invention of claim 5 of the present application, the same effect as that of the device invention of claim 1 of the present application can be obtained.

It is a side view which shows roughly the principal part of the laser welding apparatus which concerns on embodiment of this invention. It is a control block diagram of the said laser welding apparatus. It is a figure which shows the laser beam irradiation site | part of two metal plates currently in laser welding by the said laser welding apparatus, and the state of the vicinity. It is explanatory drawing for demonstrating the method to estimate the shape of a molten pool in the said laser welding apparatus.

  Hereinafter, a laser welding apparatus and a laser welding method according to embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a side view schematically showing a main part of a laser welding apparatus according to an embodiment of the present invention, and FIG. 2 is a control configuration diagram of the laser welding apparatus. This laser welding apparatus 10 includes a laser head 2 that generates a laser beam LB, a wire supply device 3 that supplies a filler wire X to the rear of a laser beam irradiated portion L from the laser head 2, and a filler wire X that is a predetermined one. A wire heating device 4 for heating to a temperature and an arm-type welding robot 5 that supports the laser head 2 and the wire supply device 3 and moves relative to the workpiece W are provided. In FIG. 1, only the tip of the robot arm 51 of the welding robot 5 is shown.

  In the present embodiment, as the work W, two flat metal plates W1 and W2 that are stacked one above the other are shown as an example. The two metal plates W1 and W2 are gripped by the plurality of clamp jigs 8. However, a gap Z is generated between the opposing surfaces because of the accuracy of the metal plates W1 and W2.

  The laser head 2 is configured using a high output laser such as a YAG laser or a carbon dioxide gas laser, and the laser output is variable. Further, although the focal position of the laser beam is variable, in the present embodiment, it is set on the lower surface of the lower metal plate W2. The laser head 2 is attached to the tip of the robot arm 51 via a mounting bracket 52. The mounting bracket 52 includes a rectangular portion 52a that is formed in a planar shape and extends along the robot arm 51, and a curved portion 52b that curves from the rectangular portion 52a to the rear side in the welding direction. The laser head 2 is attached to the rectangular portion 52a.

  The wire supply device 3 is driven by a wire supply nozzle 31 and a wire supply motor 33 (see FIG. 2) disposed in the vicinity of the irradiated portion L of the laser beam LB on the rear side in the welding progress direction with respect to the laser beam LB. And a tube 32 that guides the filler wire X fed from a wire roll (not shown) around which the filler wire X is wound to the wire supply nozzle 31. The wire supply motor 33 is configured by a servo motor capable of controlling the rotation speed, and thereby the supply amount of the filler wire X to the welded portion can be adjusted.

  The wire supply nozzle 31 is also attached to the tip of the robot arm 51 via a mounting bracket 52. Specifically, a moving plate 53 configured to be movable in the horizontal direction with respect to the mounting bracket 52 by the wire nozzle horizontal moving mechanism 55 (see FIG. 2) is attached to the curved portion 52b of the mounting bracket 52. A rotation shaft 54 configured to be rotatable with respect to the moving plate 53 is attached to the plate 53 by a wire nozzle rotation drive mechanism 56 (see FIG. 2), and the wire supply nozzle 31 is attached to the rotation shaft 54. It has been.

  In this way, the laser head 2 and the wire supply nozzle 31 are attached to the tip of the robot arm 51, and the wire supply nozzle 31 is disposed on the rear side in the welding progress direction of the laser head 2 and is relative to the laser head 2. In addition, the wire nozzle is horizontally moved by the wire nozzle horizontal moving mechanism 55 and is rotated by the wire nozzle rotating drive mechanism 56. The laser head 2 and the wire supply nozzle 31 are welded to the center LBc of the laser beam LB emitted from the laser head 2 and the filler wire X supplied from the wire supply nozzle 31, as shown in FIG. The position is adjusted so as to move along the route R.

  The wire heating device 4 heats the wire X with Joule heat generated in the wire X by energizing the filler wire X. The heating power supply device 41, the heating power supply device 41, the wire supply nozzle 31, A nozzle connection cable 42 for connecting the heating power supply device 41 and the clamping jig 8, that is, a metal plate connection cable 43 for connecting the heating power supply device 41 and the metal plates W 1, W 2. The current flowing from the power supply device 41 returns to the heating power supply device 41 via the nozzle connection cable 42, the wire supply nozzle 31, the filler wire X, the metal plates W1, W2, the clamp jig 8, and the metal plate connection cable 43. ing. Of course, the current may flow in the reverse direction.

  Here, the predetermined temperature is such that the end of the filler wire X is supplied to a molten pool WY shown in FIG. 3 to be described later, and is about a predetermined depth in the molten pool WY, for example, about half the plate thickness of the upper metal plate W1. Is set to a temperature that melts with the heat of the wire heating device 4 and the heat of the molten pool WY. The current value for heating the filler wire X to a predetermined temperature may be derived by conducting an experiment or the like.

  The laser welding apparatus 10 according to the present embodiment further includes a first imaging device 6 as a first imaging unit that images the laser beam irradiated portion L of the workpiece W and the vicinity thereof from above the upper metal plate W1. And a second imaging device 7 as second imaging means for imaging the laser beam irradiated portion L of the workpiece W1 and the vicinity thereof from the lower side of the lower metal plate W2. The first imaging device 6 and the second imaging device 7 are configured so as to be able to acquire images at predetermined intervals using, for example, a CCD camera, and the first imaging device 6 images the upper surface of the molten pool WY. The second imaging device 7 can image the lower surface of the molten pool WY.

  As shown in FIG. 2, the laser welding apparatus 10 includes a laser head 2, a wire supply motor 33 of the wire supply apparatus 3, a wire nozzle horizontal movement mechanism 55, a wire nozzle rotation drive mechanism 56, a wire heating apparatus 4, and A control unit 60 that comprehensively controls the configuration related to the laser welding apparatus 10 such as the operation of the welding robot 5 is provided. The control unit 60 controls the operation of the wire nozzle horizontal movement mechanism 55 and the wire nozzle rotation drive mechanism 56 to adjust the entry position and the entry angle of the filler wire X with respect to the molten pool WY. Based on the upper surface shape of the molten pool WY imaged by the adjustment unit 61 and the first imaging device 6 and the lower surface shape of the molten pool WY imaged by the second imaging means 7, the internal shape of the molten pool WY is determined. A molten pool shape estimation unit 62 as a molten pool shape estimation means to estimate, and the wire supply adjustment unit 61 applies to the molten pool WY based on the internal shape of the molten pool WY estimated by the molten pool shape estimation unit 62. The entry position and the entry angle of the filler wire X can be adjusted. Note that the control unit 60 is configured with, for example, a microcomputer as a main part.

  When laser welding is performed using the laser welding apparatus 10 configured as described above, as shown in FIG. 1, first, two flat metal plates W1 and W2 are overlapped in the vertical direction. The metal plates W1 and W2 are gripped by the clamp jig 8 at a predetermined position. As described above, the gap Z is generated between the opposing surfaces of the two metal plates W1 and W2.

  And while irradiating the laser beam LB toward the upper metal plate W1 surface of the two metal plates W1 and W2, the laser beam LB is applied to the two metal plates W1 and W2 along the welding path. By moving relatively, the molten metal of the upper and lower metal plates W1 and W2 is melted by melting the laser beam irradiated portions L of the upper and lower metal plates W1 and W2, and the molten metal in the upper and lower metal plates W1 and W2 is stored. From the upper surface to the lower surface of the lower metal plate W2. Then, the filler wire X heated so as to be melted with the heat of the molten pool is supplied to the molten pool from the rear side in the welding progress direction with respect to the laser beam LB, and thereby the filler wire X is melted and melted into the molten pool. Supply additional metal.

  FIG. 3 is a view showing a portion irradiated with laser light of two metal plates during laser welding by the laser welding apparatus and a state in the vicinity thereof. FIG. FIG. 3B is a cross-sectional view taken along line Y3b-Y3b in FIG. 3A. FIG.

  Describing in detail with reference to FIG. 3, first, in the vicinity of the front of the center LBc of the laser beam LB in the welding path R, the metal in the vicinity of the center LBc of the laser beam LB in the upper metal plate W1 is melted, and the molten metal Wy is formed. Has been generated. In the laser beam irradiated portion L irradiated with the laser beam LB, the metal is turned into a plasma state by the laser beam LB, and the keyhole WK is formed by pushing the molten metal Wy around by the pressure.

  At the position of the laser beam center LBc in the welding path R, the keyhole WK passes through the upper metal plate W1 and reaches the lower metal plate W2. In the lower metal plate W2, the metal in the vicinity of the laser beam center LBc is melted to produce a molten metal Wy. Further, the molten metal Wy of the upper metal plate W1 starts to hang down to the lower metal plate W2 side due to gravity.

  In the vicinity of the rear of the center LBc of the laser beam LB in the welding path R, the molten metal Wy of the upper metal plate W1 hangs down due to gravity, and in the position behind the laser beam center LBc in the melting path R, the molten metal Wy. However, the molten pool WY, which is carried to the previously formed keyhole WK and stores the molten metal Wy, is formed from the upper surface of the upper metal plate W1 to the lower surface of the lower metal plate W2.

  In this embodiment, the filler wire X heated so as to be melted with the heat of the molten pool WY is supplied to the molten pool WY from the rear side in the welding progress direction with respect to the laser beam LB, and the filler wire X is melted and melted. Metal Wy ′ is produced. Then, the newly generated molten metal Wy ′ is supplied into the molten pool WY, so that the molten metal Wy in the molten pool WY that originally existed is pushed downward as indicated by a dotted arrow. As a result, the downward drooping of the molten metal Wy beyond the gap Z is promoted, and the upper metal plate W1 and the lower metal plate W2 are connected by the molten metal Wy.

  Then, at a position further rearward than the laser beam center LBc in the welding path R, the molten metal Wy, Wy ′ of the molten pool WY starts to solidify from the lower side, and further behind, the molten metal Wy, Wy of the molten pool WY. 'Is solidified from the top to the bottom, and a non-molten welded portion WB is formed.

Here, the supply of the filler wire X to the molten pool WY will be further described.
As shown in FIG. 3, the filler wire X is supplied to the molten pool WY along the welding path R, and is supplied so as to enter the molten pool WY while being inclined forward and downward as indicated by an arrow β. Is done. More specifically, the filler wire X has a position in which the filler wire X enters the molten pool WY, that is, a front end position Xp in the welding progress direction where the filler wire X intersects the upper surface of the molten pool WY, from the laser beam center LBc to the rear of the welding path R. Of the filler wire X with respect to the molten pool WY, that is, the angle formed by the filler wire X and the upper surface of the molten pool WY is θ. Further, the filler wire X that enters the molten pool WY is supplied so as to be melted at a predetermined penetration depth H.

  And as shown in FIG. 3, the filler wire X supplied to the molten pool WY does not enter the keyhole WK formed in the molten pool WY, and the rear end side in the welding progress direction of the molten pool WY. It is made to enter into the molten pool WY so as not to come into contact with the shape of the metal plate, that is, so as not to come into contact with the metal plates W1, W2 and the welded portion WB in the non-molten state.

  In the present embodiment, the entry position Xp of the filler wire X is set so that the distance D is, for example, twice the beam diameter of the laser beam LB, and the entry angle θ of the filler wire X is set to 70 °, for example. Is done. Further, the filler wire X that enters the molten pool WY is preferably set so that the penetration depth H is within the range of the plate thickness of the upper metal plate W1.

  In this way, the molten metal Wy ′ of the filler wire X is added to the molten metal Wy of the metal plates W1 and W2 by laser welding the two metal plates W1 and W2 while supplying the filler wire X. It is possible to increase the amount, and by allowing the filler wire X to enter the molten pool WY, it is possible to promote the downward droop of the molten metal Wy of the upper metal plate W1, and the two metal plates W1, W2 Even when a relatively large gap Z is generated therebetween, the upper and lower metal plates W1 and W2 can be well connected.

  As described above, when laser welding the two metal plates W1 and W2 while supplying the filler wire X, the molten pool WY depends on the size of the gap Z formed between the two metal plates W1 and W2. Since the inner shape of the filler wire X changes, the filler wire X comes into contact with the non-molten metal plates W1, W2 and the welded portion WB forming the outer peripheral surface of the molten pool WY, or the laser beam LB enters the molten pool WY. In this embodiment, the upper surface of the molten pool WY and the lower surface of the molten pool WY are respectively imaged, and the upper surface shape of the imaged molten pool WY and the molten pool WY are captured. By estimating the internal shape of the molten pool WY based on the shape of the lower surface of the weld pool and adjusting the entry position and the entry angle of the filler wire X with respect to the molten pool WY based on the estimated internal shape of the molten pool WY, Or To work around the problem.

Hereinafter, a method of adjusting the entry position and the entry angle of the filler wire X with respect to the molten pool WY will be described with reference to FIG.
FIG. 4 is an explanatory diagram for explaining a method of estimating the shape of the molten pool in the laser welding apparatus. In FIG. 4, fillers are used for the cross sections of the two metal plates W1 and W2 along the welding path R. A state is schematically shown in which laser welding is performed while the wire X is supplied to the molten pool WY from the rear side in the welding progress direction with respect to the laser beam LB.

  As described above, in the laser welding apparatus 10 according to the present embodiment, the upper surface of the molten pool WY is imaged by the first imaging device 6, and the lower surface of the molten pool WY is imaged and imaged by the second imaging device 7. The images of the upper surface shape and the lower surface shape of the molten pool WY are input to the molten pool shape estimation unit 62. And the molten pool shape estimation part 62 estimates the internal shape of the molten pool WY based on the image of the upper surface shape and lower surface shape of the molten pool WY input.

  In the molten pool shape estimation unit 62, an image of the upper surface shape of the molten pool WY is image-processed, and the upper surface shape of the molten pool WY is subjected to the welding progress direction rear end position P1 and the welding progress direction front end position P2 and The welding progress direction rear end position P3 and the welding progress direction front end position P4 of the formed keyhole WK are detected, and the lower surface shape image of the molten pool WY is image-processed to perform the lower surface shape welding progress direction of the molten pool WY. An end position P5, a welding progress direction front end position P6, and a position P7 where the lower surface of the weld pool WY intersects the laser beam center LBc are detected.

  Next, the weld pool shape estimation unit 62 determines the position P1 based on the detected welding progress direction rear end position P1 of the upper surface shape of the weld pool WY and the welding progress direction rear end position P5 of the lower surface shape of the weld pool WY. And a position S5 in a straight line are estimated as the shape on the rear end side in the welding progress direction inside the weld pool WY, and the front end position P2 and the weld pool WY in the welding progress direction of the detected upper surface shape of the weld pool WY. The shape S2 connecting the position P2 and the position P6 in a straight line is estimated to be the shape on the front end side in the welding progress direction inside the molten pool WY, based on the lower end shape of the welding progress direction front end position P6.

  Further, in the molten pool shape estimation unit 62, the position P7 where the rear end position P3 of the keyhole WK formed in the upper surface of the detected molten pool WY in the welding progress direction, the lower surface of the molten pool WY, and the laser beam center LBc intersect. Based on the above, the shape S3 that linearly connects the position P3 and the position P7 is estimated and detected as the shape of the keyhole WK formed in the weld pool WY by the laser beam LB on the rear end side in the welding progress direction. The position P4 and the position P7 are based on the front end position P4 of the welding progress direction of the keyhole WK formed on the upper surface of the molten pool WY and the position P7 where the lower surface of the molten pool WY intersects the laser beam center LBc. The shape S4 connected in a straight line is estimated as the shape on the front end side in the welding progress direction of the keyhole WK formed in the weld pool WY by the laser beam LB.

  The wire supply adjustment unit 61 controls the operation of the wire nozzle horizontal movement mechanism 55 and / or the wire nozzle rotation drive mechanism 56 based on the shape inside the molten pool WY estimated by the molten pool shape estimation unit 62. The entrance position Xp and the entrance angle θ of the filler wire X with respect to the molten pool WY are adjusted. Specifically, the extension line IL of the filler wire X that enters the molten pool WY at the predetermined entry position Xp at the predetermined entry angle θ and enters the predetermined depth of penetration H is formed inside the estimated molten pool WY. The filler wire X enters the molten pool WY so as not to intersect the portion corresponding to the upper metal plate W1 (the portion connecting the position P1 and the position P10 in the shape S1) of the shape S1 on the rear end side in the welding progress direction. The position Xp and the approach angle θ are adjusted.

  Here, the filler for the molten pool WY is not crossed with the portion corresponding to the upper metal plate W1 in the shape S1 on the rear end side in the welding progress direction inside the molten pool WY where the extension line IL of the filler wire X is estimated. The entry position Xp and the entry angle θ of the wire X are adjusted because the filler wire X entering the molten pool WY is more likely to be melted as the penetration depth H becomes deeper, and the metal plate W1 on the upper side of the molten pool WY. This is because it is possible to avoid the filler wire X from being melted in the part other than the corresponding part and coming into contact with the metal plate W2 in the non-molten state.

  In this way, when the two metal plates W1 and W2 stacked one above the other while supplying the filler wire X are laser welded, the extension line IL of the filler wire X entering the molten pool WY is The entry position Xp and the entry angle θ of the filler wire X with respect to the molten pool WY are set so as not to intersect the portion corresponding to the upper metal plate W1 in the estimated shape S1 on the rear end side in the welding progress direction inside the molten pool WY. Since the adjustment is made, the filler wire X can be supplied to a suitable position in the molten pool WY without bringing the filler wire X into contact with the unmelted metal plate W1 or the welded portion WB.

  Further, the wire supply adjusting unit 61 enters the molten pool WY at a predetermined entry position Xp at a predetermined entry angle θ, and an extension line IL of the filler wire X that enters to a predetermined entry depth H is estimated laser. The portion corresponding to the upper metal plate W1 in the shape S3 on the rear end side in the welding progress direction of the keyhole WK formed in the molten pool WY by the light LB (the portion connecting the position P3 and the position P11 in the shape S3) The operation of the wire nozzle horizontal movement mechanism 55 and / or the wire nozzle rotation drive mechanism 56 is controlled so as not to intersect with the welding position, and the entry position Xp and the entry angle θ of the filler wire X with respect to the molten pool WY are adjusted.

  Here, an extension line IL of the filler wire X is estimated so that the filler wire X with respect to the molten pool WY does not intersect with the portion corresponding to the upper metal plate W1 in the welding progress direction rear end shape S3 of the keyhole WK. The approach position Xp and the approach angle θ are adjusted because the filler wire X entering the molten pool WY is more easily melted as the approach depth H becomes deeper, and corresponds to the metal plate W1 on the upper side of the molten pool WY. This is because it is possible to avoid the filler wire X from being melted and entering the keyhole WK in the portion excluding.

  Further, the shape of the keyhole WK formed in the weld pool WY by the laser beam LB on the rear end side in the welding progress direction is the position P3 of the keyhole WK formed in the upper surface of the weld pool WY on the rear end side in the welding progress direction. The shape S3 that linearly connects the lower surface of the molten pool WY and the position P7 where the laser beam center LBc intersects is estimated to be during laser welding when the keyhole WK is not formed on the lower surface of the molten pool WY. This is because the actual shape of the keyhole WK on the rear end side in the welding progress direction is formed at least on the front side in the welding progress direction with respect to the estimated shape S3 of the keyhole WK on the rear end side in the welding progress direction. .

  On the other hand, when the keyhole WK is formed up to the lower surface of the molten pool WY, the molten pool shape estimation unit 62 performs image processing on an image of the lower surface shape of the molten pool WY and forms the keyhole WK on the lower surface of the molten pool WY. The welding progress direction rear end position and the welding progress direction front end position are detected, and the detected welding progress direction rear end position of the keyhole WK formed on the lower surface of the weld pool WY and the upper surface of the weld pool WY are formed. Based on the welding progress direction rear end position P3 of the keyhole WK, the shape connecting these positions in a straight line is estimated as the shape of the keyhole WK on the rear end side in the welding progress direction, and the detected molten pool WY A shape that connects these positions in a straight line based on the front end position of the keyhole WK formed on the lower surface in the welding progress direction and the front end position P4 of the keyhole WK formed on the upper surface of the weld pool WY. Estimating a welding direction front end side of the shape of the keyhole WK.

  The wire supply adjusting unit 61 then melts the estimated shape of the rear end side of the keyhole WK in the welding progress direction, that is, the position of the rear end of the keyhole WK formed in the lower surface of the molten pool WY and the welding progress direction. A portion corresponding to the upper metal plate W1 in a shape connecting the rear end position P3 of the keyhole WK formed in the upper surface of the pond WY in a straight line and a predetermined position at the predetermined entry position Xp to the molten pool WY. The operation of the wire nozzle horizontal movement mechanism 55 and / or the wire nozzle rotation drive mechanism 56 is controlled so that the extension line IL of the filler wire X entering at a predetermined entry depth H does not intersect. Then, the filler wire entry position Xp and the entry angle θ with respect to the molten pool WY are adjusted.

  In this way, when the two metal plates W1 and W2 stacked one above the other while supplying the filler wire X are laser welded, the extension line IL of the filler wire X entering the molten pool WY is The entry position Xp and the entry angle θ of the filler wire X with respect to the molten pool WK are adjusted so as not to intersect the portion corresponding to the upper metal plate W1 in the estimated shape of the keyhole WK. The filler wire X can be supplied to a suitable position in the molten pool WY without entering the keyhole WK.

  Thus, in this embodiment, the filler wire X that enters the molten pool WY is set so that the penetration depth H is within the range of the thickness of the upper metal plate W1, and enters the molten pool WY. The extension line IL of the filler wire X that enters at an entrance angle θ in Xp does not intersect the portion corresponding to the upper metal plate W1 in the estimated shape S1 on the rear end side in the welding progress direction inside the molten pool WY. And the approach position Xp and the entrance angle of the filler wire X with respect to the molten pool WY so as not to intersect with the portion corresponding to the upper metal plate W1 in the estimated shape S3 of the rear end side of the welding progress direction of the keyhole WK θ is adjusted.

  That is, the filler wire X that enters the molten pool WY has an extension line IL of the filler wire X that enters the molten pool WY at the entry position Xp at the entry position Xp, and the rear end in the welding progress direction inside the estimated molten pool WY. A position P10 corresponding to the lower surface of the upper metal plate W1 in the shape S1 and a position P11 corresponding to the lower surface of the upper metal plate W1 in the estimated shape S3 on the rear end side in the welding progress direction of the keyhole WK. The entry position Xp and the entry angle θ of the filler wire X with respect to the molten pool WY are adjusted so as to intersect with the linearly connected portion.

  As a result, the filler wire X that has entered the molten pool WY comes into contact with the upper molten metal plate W1 or the welded portion WB or enters the keyhole WK formed in the upper molten metal plate W1. This can be prevented, and the filler wire X can be supplied to a suitable position in the molten pool WY.

  As described above, in this embodiment, the filler wire X is welded to the molten pool WY formed by the laser beam LB from the upper surface of the upper metal plate W1 to the lower surface of the lower metal plate W2, as compared with the laser beam LB. When supplying from the rear side in the direction, based on the upper surface shape of the molten pool WY imaged by the first imaging means 6 and the lower surface shape of the molten pool WY imaged by the second imaging means 7, The internal shape is estimated, and the entry position Xp and the entry angle θ of the filler wire X with respect to the molten pool WY are adjusted based on the estimated internal shape of the molten pool WY. The filler wire X can be supplied to a suitable position in the molten pool WY without being brought into contact with W1 or the welded part WB or entering the keyhole WK. To stabilize the welding by the Ya supply state substantially constant, it is possible to satisfactorily laser welding two metal plates W1, W2. Even when the internal shape of the molten pool WY changes, such as when the size of the gap Z generated between the two metal plates W1, W2 changes, the filler wire depends on the estimated internal shape of the molten pool WY. X can be supplied to a suitable position in the molten pool WY, and the above effect can be obtained effectively.

  In the embodiment described above, the wire supply adjustment unit 61 converts the upper surface shape of the molten pool WY imaged by the first imaging device 6 and the lower surface shape of the molten pool WY imaged by the second imaging device 7. Based on the welding progress direction rear end position P1 of the upper surface shape of the molten pool WY and the welding progress direction rear end position P5 of the lower surface shape of the molten pool WY, the shape S1 linearly connects the welding progress direction inside the molten pool WY. Although it is estimated that the shape is the end side, the rear end position P1 in the welding progress direction of the upper surface shape of the molten pool WY and the position where the laser beam center LBc intersects the lower surface of the lower metal plate W2 are linearly formed. It is also possible to estimate the shape to be tied as the shape on the rear end side in the welding progress direction inside the molten pool WY.

  Even in such a case, in the wire supply adjusting unit 61, the extension line IL of the filler wire X entering the molten pool WY at the predetermined entry position Wp at the predetermined entry angle θ is the welding progress inside the estimated molten pool WY. The entry position Xp and the entry angle θ of the filler wire X with respect to the molten pool WY are adjusted so as not to intersect with the portion corresponding to the upper metal plate W1 in the shape on the rear end side in the direction. Thereby, the filler wire X can be supplied to the suitable position in the molten pool WY, without making the filler wire X entered into the molten pool WY contact the non-molten metal plate W1 or the to-be-welded part WB. .

  In this case, the welding progress inside the molten pool WY estimated based on the upper surface shape of the molten pool WY and the lower surface shape of the molten pool WY imaged using the first imaging device 6 and the second imaging device 7. Since the shape on the rear end side in the welding progress direction inside the molten pool WY estimated from the shape S1 on the rear end side in the direction is estimated on the front side in the welding progress direction, the second imaging device 7 is used. In addition, the above effect can be effectively obtained by using one imaging device 6.

  As described above, the present invention is not limited to the illustrated embodiments, and it goes without saying that various improvements and design changes can be made without departing from the gist of the present invention.

  In the present invention, when two metal plates stacked on top and bottom are fed while supplying filler wires, even when the gap formed between the metal plates changes, the upper and lower metal plates are connected well. The laser welding apparatus and the laser welding method can be provided and can be widely used not only in the automobile industry but also in industries that require welding of two metal plates.

6 First imaging device 7 Second imaging device 10 Laser welding device 60 Control unit 61 Wire supply adjustment unit
62 Molten pool shape estimation part LB Laser beam R Welding path W1, W2 Metal plate WK Keyhole Wy, Wy 'Molten metal WY Molten pool X Filler wire Xp Filler wire entry position θ Filler wire entry angle

Claims (5)

While irradiating a laser beam toward the upper metal plate surface of the two metal plates stacked one above the other, the laser beam is relatively directed to the two metal plates along a predetermined welding path. And forming a molten pool in which the molten metal is stored by melting two metal plates by moving the laser beam from the upper surface of the upper metal plate to the lower surface of the lower metal plate, and a filler wire is formed in the molten pool Is a laser welding apparatus that laser-welds two metal plates while supplying filler wire from the rear side of the welding progress direction than laser light,
Wire supply adjusting means for adjusting the entry position and the entry angle of the filler wire with respect to the molten pool;
First imaging means for imaging the upper surface of the molten pool;
Second imaging means for imaging the lower surface of the molten pool;
A molten pool shape that estimates an internal shape of the molten pool based on an upper surface shape of the molten pool imaged by the first imaging unit and a lower surface shape of the molten pool imaged by the second imaging unit. An estimation means;
With
The wire supply adjusting means adjusts the entry position and the entry angle of the filler wire with respect to the molten pool based on the internal shape of the molten pool estimated by the molten pool shape estimating means.
A laser welding apparatus characterized by that. In the laser welding apparatus according to claim 1,
The molten pool shape estimating means includes a rear end position in the welding progress direction of the upper surface shape of the molten pool imaged by the first imaging means, and a lower surface shape of the molten pool imaged by the second imaging means. Based on the welding progress direction rear end position, estimate the shape of the welding progress direction rear end side inside the molten pool,
The wire supply adjusting means is configured so that an extension line of the filler wire entering the molten pool at a predetermined entry position at a predetermined entry position is after the welding progress direction inside the molten pool estimated by the molten pool shape estimating means. Adjust the entry position and the entry angle of the filler wire with respect to the molten pool so as not to intersect with the portion corresponding to the upper metal plate in the end side shape,
A laser welding apparatus characterized by that. In the laser welding apparatus according to claim 1 or 2,
The molten pool shape estimation means includes a welding progress direction rear end position of the upper surface shape of the molten pool imaged by the first imaging means and a lower surface shape weld of the molten pool imaged by the second imaging means. Estimating the shape that linearly connects the rear end position in the traveling direction as the shape on the rear end side in the welding traveling direction inside the molten pool,
A laser welding apparatus characterized by that. In the laser welding apparatus according to any one of claims 1 to 3,
The molten pool shape estimating means uses the laser light based on the upper surface shape of the molten pool imaged by the first imaging means and the lower surface shape of the molten pool imaged by the second imaging means. Estimating the shape of the keyhole formed in the molten pool,
The wire supply adjusting means is configured such that an extension line of the filler wire entering the molten pool at a predetermined entry position at a predetermined entry position is an upper side of the keyhole shape estimated by the molten pool shape estimating means. Adjusting the entry position and the entry angle of the filler wire with respect to the molten pool so as not to intersect with the portion corresponding to the metal plate of
A laser welding apparatus characterized by that. While irradiating a laser beam toward the upper metal plate surface of the two metal plates stacked one above the other, the laser beam is relatively directed to the two metal plates along a predetermined welding path. And forming a molten pool in which the molten metal is stored by melting two metal plates by moving the laser beam from the upper surface of the upper metal plate to the lower surface of the lower metal plate, and a filler wire is formed in the molten pool Is a laser welding method in which two metal plates are laser-welded while supplying filler wire from the rear side of the welding progress direction than laser light,
The upper surface of the molten pool and the lower surface of the molten pool are respectively imaged, and based on the imaged upper surface shape of the molten pool and the lower surface shape of the molten pool, the internal shape of the molten pool is estimated and estimated. Further, based on the internal shape of the molten pool, the entry position and the entry angle of the filler wire with respect to the molten pool were adjusted,
A laser welding method characterized by that.

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