JP2017131914A - Welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a joint geometry error during welding and to control welding conditions based on a detection result.SOLUTION: A wire 4 fed to a joint 3 is irradiated with a laser beam L, and the laser beam L is scanned along the joint 3, whereby a component to be welded is welded. A geometry of the joint 3 at a position separated from a position at which the laser beam L is radiated by a prescribed distance is measured prior to radiation of the laser beam L. A diameter a of the laser beam L is so controlled as to be larger than a width of the joint 3. According to increasing/decreasing of the diameter a of the laser beam L, an output of the laser beam L is increased/decreased. A feed speed of the wire 4 is controlled based on an area of a cross section of the joint 3 perpendicular to a scanning direction of the laser beam L, the diameter a of the laser beam L, and a diameter of the wire 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a welding method.

  In order to achieve the desired welding quality when welding the welded member, groove shape errors such as the gap amount and level difference of the welded part are detected, and weaving amplitude, wire feed amount, laser output, It is necessary to control welding conditions such as welding speed.

  As a technique for controlling such welding conditions, there has been proposed a laser welding apparatus that controls welding conditions according to the shape of a groove stored prior to the start of welding (Patent Document 1). In this laser welding apparatus, basic welding conditions such as laser output, welding speed, and weaving amplitude corresponding to the thickness of the member to be welded are stored in the storage means for each weld line. The storage means stores a control amount of the weaving amplitude corresponding to the groove shape error for each basic welding condition. Then, the basic welding condition of the welding line selected by the selection means and the control amount of the weaving amplitude corresponding to the detection data detected by the error detection means are selected from the storage means. As a result, welding is performed for each weld line based on the basic welding conditions and the control amount of the weaving amplitude. Thereby, even when there is a groove shape error such as a gap amount or a step amount in the welded portion, high-quality welding can be performed.

JP 2003-170284 A

  However, in the above laser welding apparatus, in order to detect a groove shape error of the welded portion, it is necessary to store in advance a groove shape as a reference before starting welding. Therefore, it is impossible to set appropriate welding conditions in the first place for the welded portion of the groove shape that is not stored.

  The present invention has been made in view of the above circumstances, and an object thereof is to detect a groove shape error during welding and to control welding conditions based on the detection result.

  A welding method according to one aspect of the present invention is a welding method for welding a member to be welded by irradiating a laser beam onto a wire fed to a groove and scanning the laser beam along the groove. The groove shape measured at a predetermined distance from the position irradiated with the laser beam is measured prior to the irradiation with the laser beam, and the diameter of the laser beam is measured as the width of the measured groove. And the output of the laser beam is increased / decreased according to the increase / decrease of the diameter of the laser beam, the area of the groove in the cross section perpendicular to the scanning direction of the laser beam, and the laser beam The wire feeding speed is controlled based on the diameter of the wire and the diameter of the wire.

  According to the present invention, it is possible to detect a groove shape error during welding and control welding conditions based on the detection result.

FIG. 3 is a perspective view schematically showing a welded portion in the welding method according to the first embodiment. It is a figure which shows typically the structure of the welding apparatus concerning Embodiment 1. FIG. It is sectional drawing which shows typically an example of the cross section (YZ cross section) after the welding of the to-be-welded member concerning Embodiment 1. FIG. It is sectional drawing which shows typically an example of the cross section (YZ cross section) of a groove | channel. It is sectional drawing which shows typically a cross section (YZ cross section) when the width | variety of a groove | channel is narrow. It is sectional drawing which shows typically the cross section (YZ cross section) in case the width | variety of a groove | channel is wide. 3 is a flowchart showing a welding method according to the first embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted as necessary.

Embodiment 1
A welding method according to the first embodiment will be described. FIG. 1 is a perspective view schematically showing a welded portion in the welding method according to the first embodiment. As shown in FIG. 1, here, an example in which the welded members 1 and 2 are welded will be described. Here, the direction in which welding proceeds is defined as the X direction. A direction perpendicular to the X direction and parallel to the main surfaces of the welded members 1 and 2 is defined as a Y direction. A direction perpendicular to the X direction and the Y direction is taken as a Z direction.

  The to-be-welded member 1 and the to-be-welded member 2 are arranged to be butted in the Y direction (so-called butt joint). Here, at the joint between the member to be welded 1 and the member to be welded 2, a part of the member to be welded 2 rides on the member to be welded 1. However, this is only an example, and it is not essential that a part of the welded member 2 rides on the welded member 1. Further, a groove 3 which is a groove extending in the X direction is provided at the joint between the member to be welded 1 and the member to be welded 2.

  The welding proceeds along the groove 3 in a direction from the − side in the X direction of FIG. 1 toward the + side, for example. A laser beam L is irradiated from the Z direction to the wire 4 made of a filler material disposed on the groove 3, and the wire 4 melts at the groove 3. As a result, a molten pool 5 in which the melted welded member 1, the welded member 2 and the wire 4 are melted is formed, and the weld pool 6 is formed by solidifying the molten pool 5. Accordingly, the welded member 1 and the welded member 2 are welded by the laser beam L scanning the groove 3 in the welding direction (X direction).

  A configuration example of an apparatus that performs the welding method according to the present embodiment will be described. FIG. 2 is a diagram schematically illustrating the configuration of the welding apparatus 100 according to the first embodiment. The welding apparatus 100 includes a processing head 10, a groove shape measuring instrument 11, a control unit 12, a laser oscillator 13, a wire feeding device 14, and a driving device 15.

  The machining head 10 irradiates the welded portion with the laser beam L output from the laser oscillator 13. Moreover, the processing head 10 guides the wire 4 fed by the wire feeding device 14 to the welded portion, for example, via the wire guide 14A.

  The groove shape measuring instrument 11 irradiates, for example, the line laser 11 </ b> A to the groove 3 ahead (+ side in the X direction) by a predetermined distance from the irradiation position of the current laser beam L. 3 cross-sectional (YZ plane) shape is measured. The measurement result is output to the control unit 12. The groove shape measuring instrument 11 can be attached to the machining head 10, for example.

  The driving device 15 is configured to be able to drive the machining head 10. The drive device 15 can be configured as an NC (Numerical Control) processing machine or a robot, for example.

  The control unit 12 controls the laser output P of the laser oscillator 13, the wire feeding speed Vf of the wire feeding device 14, and the driving speed of the machining head 10 of the driving device 15. Moreover, the control part 12 controls the beam diameter a of the laser beam L irradiated to a welding part. For example, the control unit 12 can control the beam diameter a of the laser beam L by controlling the laser oscillator 13 and controlling an optical element (for example, a lens optical system) provided in the processing head 10. For example, when the laser beam L is not a parallel beam but a tapered beam converged on the groove 3 (not shown), the control unit 12 moves the machining head 10 in the optical axis direction of the laser beam L. By moving in the (Z direction), the beam diameter a of the laser beam L can also be controlled.

Next, the welding method according to the present embodiment will be described. FIG. 3 is a cross-sectional view schematically illustrating an example of a cross section (YZ cross section) after welding of the welded members 1 and 2 according to the first embodiment. When the groove 3 is welded, a weld bead 6 formed by solidifying the welded member 1, the welded member 2, and the wire 4 is formed. Hereinafter, an extra prime height H _W height to the top of the (Z direction) of the welding bead 6 from the surface of the member to be welded 1 and 2.

  FIG. 4 is a cross-sectional view schematically showing an example of a cross section (YZ cross section) of the groove 3. In the present embodiment, the member to be welded 1 is provided with a gradient portion 1A, and the member to be welded 2 is provided with a gradient portion 2A, whereby the groove 3 is configured as a substantially V-shaped groove. Here, the top width (Y direction) of the V-shaped groove is W1, the bottom width (Y direction) is W2, the height of the gradient parts 1A and 2A (Z direction) is D1, and the height other than the gradient part is D2. And

  In welding, errors occur in the shape of the groove 3 due to manufacturing errors of the members 1 and 2 to be welded and variations in arrangement of the members 1 and 2 to be welded. FIG. 5 is a cross-sectional view schematically showing a cross section (YZ cross section) when the width of the groove 3 is narrow. In this case, if welding is performed without considering the error, the cross-sectional area of the V-shaped groove of the groove 3 is small, so that the weld bead becomes excessive and the surplus height becomes too high.

  FIG. 6 is a cross-sectional view schematically showing a cross section (YZ cross section) when the width of the groove 3 is wide. In this case, if welding is performed without taking account of the error, the cross-sectional area of the V-shaped groove of the groove 3 is large, so that a portion that is not welded to the groove 3 is generated, and a sufficiently strong joint is formed. There is a risk that it may not be possible.

  As described above, since there is an error in the shape of the groove 3, an appropriate joining width (width of the joining bead in the Y direction), joining depth (depth of the joining bead in the Z direction), and surplus height In order to carry out welding at, it is necessary to control the welding conditions following the shape change of the groove. Hereinafter, the control of the welding conditions according to the present embodiment will be specifically described. FIG. 7 is a flowchart illustrating the welding method according to the first embodiment.

Step S11
The groove shape measuring instrument 11 takes in the groove shape measurement data.

Step S12
The control unit 12 measures the width and depth of the groove 3 based on the measurement result obtained by the groove shape measuring instrument 11. Specifically, the control unit 12 measures the widths W1 and W2 at the groove 3 shown in FIG. 4, and measures D1 + D2 as the depth.

Step S13
The controller 12 calculates the beam diameter a of the laser beam L from the width of the groove 3. At this time, the beam diameter a of the laser beam L is determined so as to be larger than the width W1 of the upper end of the groove 3.

但し、αは、要求される余盛り高さによって決定される０よりも大きな値である。例としては、αは０．２とすることができる。
更に、溶接による接合速度をＶｗ、ワイヤの直径をｄとすると、ワイヤ送給速度Ｖｆは、以下の式（２）で求めることができる。

Step S14
The controller 12 calculates the wire feed speed Vf from the groove widths W1 and W2 and the depths D1 and D2. Here, let S be the area of the YZ cross section (that is, the cross section perpendicular to the X direction that is the scanning direction of the laser beam L) of the bonding bead 6 that is obtained. The cross-sectional area S of the bonding bead 6 can be obtained by the following equation (1).

However, α is a value larger than 0 determined by the required extra height. As an example, α can be 0.2.
Further, when the welding speed by welding is Vw and the diameter of the wire is d, the wire feeding speed Vf can be obtained by the following equation (2).

Step S15
The controller 12 calculates the laser output P from the beam diameter a and the wire feed speed Vf. At this time, for example, the laser output can be increased or decreased in proportion to the area of the laser beam L, in other words, in proportion to the square of the beam diameter a.

Step S16
The control unit 12 updates the beam diameter a, the wire feed speed Vf, and the laser output P to the calculated values. For example, the control unit 12 controls the machining head 10, the laser oscillator 13, and the wire feeding device 14 in order to update the beam diameter a, the wire feeding speed Vf, and the laser output P to the calculated values.

Step S17
The control unit 12 determines whether or not the welding is finished. If welding has not ended, the process returns to step S11. If welding has ended, the control of the welding conditions is ended. Note that the end of welding can be appropriately detected by a command or a sensor from the user.

  As described above, according to the welding apparatus 100 according to the present embodiment, the shape of the unwelded groove 3 is measured in advance during the welding operation. The wire feed speed, laser beam output, and beam diameter of the laser beam can be controlled based on the measured width and depth of the groove 3 so that welding can be performed at a desired height. it can. Thereby, even if the groove shape changes, the welding conditions can be controlled in accordance with the shape change, so that it is possible to suitably prevent poor welding.

  In addition, in this configuration, since the shape of the groove is sequentially measured during the welding operation, it is not necessary to prepare for measuring the groove shape in advance and storing the measurement result in the welding apparatus in order to control the welding conditions. It is. Therefore, it is possible to shorten the time required for welding work.

Other Embodiments Although the above description specifically explained the invention made by the present inventor based on the embodiment, the present invention is not limited to the embodiment already described, and departs from the gist thereof. Needless to say, various modifications can be made without departing from the scope. For example, in the above description, the configuration in which the groove shape measuring device irradiates the groove with the line laser has been described, but this is merely an example. If the groove shape measuring instrument can measure the shape of the groove, the type of laser is not limited to a line laser, and the light to be irradiated is not limited to laser light. Further, the groove shape measuring device may be configured by an imaging device such as a CCD camera, and the shape of the groove may be measured from the imaged result of the groove. Further, when the groove shape measuring device is configured by an imaging device such as a CCD camera, or when an imaging device is provided separately from the groove shape measuring device, the molten pool 5 is imaged by the imaging device and the imaged melting is performed. The beam diameter of the laser beam, the output of the laser beam, and the wire feed speed may be controlled so that the size of the pond is within a predetermined range. When an imaging device is provided separately from the groove shape measuring instrument, the above-described control by the molten pool imaging can be performed in combination with the control by the groove shape measuring instrument, or one of them is preferentially performed. It is also possible.

  In the above, the control unit 12 controls the laser oscillator 13 and the like to control the beam diameter and output of the laser beam, and controls the wire feeding device 14 to control the wire feeding speed. When the control unit 12 is configured using hardware resources such as a computer, for example, these controls performed by the control unit 12 can be executed by software. Specifically, a program for performing processing necessary for controlling the beam diameter and output of the laser beam and the wire feed speed performed by the control unit 12 is executed on a hardware resource such as a computer. Thus, the control can be realized.

  The programs described above can be stored and provided to a computer using various types of non-transitory computer readable media. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (for example, flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (for example, magneto-optical disks), CD-ROM (Read Only Memory) CD-R, CD -R / W, semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (Random Access Memory)). The program may also be supplied to the computer by various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

1, 2 to-be-welded member 1A, 2A Gradient part 3 Groove 4 Wire 5 Weld pool 6 Joining bead 10 Processing head 11 Groove shape measuring instrument 11A Line laser 12 Control part 13 Laser oscillator 14 Wire feeder 14A Wire guide 15 Drive Apparatus 100 Welding apparatus a Beam diameter L Laser beam

Claims (1)

A welding method of welding a member to be welded by irradiating a laser beam on a wire fed to a groove and scanning the laser beam along the groove,
Prior to irradiation with the laser beam, the shape of the groove at a predetermined distance from the position irradiated with the laser beam is measured,
Controlling the diameter of the laser beam to be larger than the measured groove width;
In response to an increase or decrease in the diameter of the laser beam, the output of the laser beam is increased or decreased,
Controlling the feeding speed of the wire based on the area of the groove in the cross section perpendicular to the scanning direction of the laser beam, the diameter of the laser beam, and the diameter of the wire;
Welding method.

Images