JP2012240063A - Laser welding method and laser welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser welding method by which an appropriate weld bead can be obtained even when any disturbance occurs during welding, in a laser welding method wherein a filler is supplied to a welding position while applying simultaneously laser welding and arc welding by feeding a wire at a welding position of a workpiece to be welded, and to provide a laser welding equipment.SOLUTION: This equipment includes a laser generating means 9, an arc generating means 13, a heating means 20, a wire feeding means 17, a filler feeding means 18, a voltage detection means 24, a regulating means 25, and a control means 26. When the phenomenon of contact failure between a filler 7 and a weld pool 6 is detected during application of heating current to the filler 7 for heating, the control means 26 adjusts the feeding speed of the filler 7 or the tip position thereof so that the filler 7 may be contact with the weld pool 6 and conducts welding. Therefore the contact between the filler 7 and weld pool 6 can be ensured and an appropriate weld bead be obtained even when any disturbance occurs during welding.

Description

  The present invention relates to a laser welding method and a laser welding apparatus that perform laser welding and arc welding simultaneously on an object to be welded, and in particular, feed a filler while feeding a wire while performing arc welding and simultaneously heating to a welding position. The present invention relates to a laser welding method and a laser welding apparatus that perform welding by feeding.

  Laser welding is a method suitable for high-speed welding, but has a drawback in that a laser beam escapes from a gap in an object to be welded, resulting in welding defects. In order to compensate for this drawback, a method of supplying a filler and a method of using it together with consumable electrode arc welding have been proposed.

  The former has a problem in improving the melting efficiency of the filler, and the latter has a problem in independent adjustment between the welding speed of the wire and the welding current. In order to solve these problems, the inventor of the present invention supplies a filler provided separately from the arc welding wire to the welding position, and independently adjusts the welding speed and the welding current and heats the filler. Further, a method for improving the welding speed is proposed.

  FIG. 3 is a schematic diagram showing the configuration of a conventional laser welding method proposed by the inventors of the present invention. 1 is a workpiece, 2 is a laser beam, 3 is a wire, 4 is an arc generated between the wire 3 and the workpiece 1, 5 is a droplet formed by melting the wire 3, The molten pool formed by the laser beam 2 and the arc 4 on the workpiece 1, 7 is a filler fed to the welding position of the workpiece 1, and 8 is a bead formed by solidification of the molten pool 6. It is.

  Since the filler 7 can be adjusted regardless of the welding current supplied to the wire 3, by adjusting only the feeding speed of the filler 7 without increasing the amount of heat input to the workpiece 1. It is possible to increase the amount of molten metal to the molten pool 6 (see, for example, Patent Document 1).

International Publication No. 2010/021094

  In view of the problems of the prior art, the problem to be solved by the present invention is to perform filler welding at the welding position while simultaneously performing laser welding and arc welding performed by feeding a wire to the welding position of the workpiece. In the laser welding method to be supplied, when welding is performed while heating the filler by bringing the filler into contact with the workpiece and passing an electric current between the filler and the workpiece, during welding It is an object of the present invention to provide a laser welding method and a laser welding apparatus that obtain a good weld bead even when there is a disturbance.

  In order to achieve the above object, the present invention controls a laser generating means for irradiating a welding position of a workpiece to be welded, a wire feeding means for feeding a wire to the welding position, and the wire feeding means. An arc generating means for supplying electric power for arc welding to the wire and the workpiece, a filler feeding means for feeding a filler to the welding position, a heating means for passing an electric current to the filler, Voltage detecting means for detecting a voltage between the filler and the workpiece, and control means for controlling the laser generating means, the arc generating means, and the heating means by inputting a detection signal of the voltage detecting means; When the filler is heated by bringing the filler into contact with the workpiece or the molten pool and passing a heating current through the filler, the filler and the workpiece or When a sign of poor contact with the molten pool is detected, the control means adjusts the feeding speed of the filler or the tip position of the filler so that the filler and the workpiece or the molten pool come into contact with each other. It is a laser welding apparatus which performs welding while.

  Moreover, this invention is a laser welding apparatus which uses the voltage value between the said filler and the said to-be-welded object or a molten pool for the detection of the precursor of the poor contact between a filler and a to-be-welded object or a molten pool.

  Further, the present invention is a laser welding apparatus that uses a resistance value between the filler and the workpiece or the molten pool for detection of a precursor of poor contact between the filler and the workpiece or the molten pool.

  As described above, the present invention provides a laser welding method for supplying a filler to the welding position while simultaneously performing laser welding and arc welding performed by feeding a wire to a welding position of an object to be welded. When the welding object or the molten pool is brought into contact and a heating current is passed through the filler, if a precursor of a contact failure between the filler and the workpiece or the molten pool is detected, the filler and the welded pool are detected. Even if there is a disturbance during welding by adjusting the feeding speed of the filler or the tip position of the filler so that the object or the molten pool is in contact, the filler and the welded object or the molten pool Contact can be ensured and a good weld bead can be obtained.

Schematic diagram showing the configuration of the laser welding apparatus according to Embodiment 1 of the present invention. Schematic diagram showing the contact state between the filler and the molten pool Schematic diagram showing the structure of a conventional laser welding method Schematic diagram showing the configuration of a laser welding apparatus according to a reference example

(Reference example)
Before describing the present invention in detail, the configuration of another laser welding method proposed by the inventor of the present invention to further improve the welding speed by heating the filler will be described.

  FIG. 4 is a schematic diagram showing such a configuration. In addition, the same code | symbol is attached | subjected to the place which has the structure, operation | movement, and effect similar to the content shown in FIG. 3, detailed description is abbreviate | omitted, and it demonstrates centering on a different part.

  Reference numeral 9 denotes a laser generating means comprising a laser oscillator 10, a laser transmission means 11, and a condensing optical system 12. 13 is connected to the torch 16 through which the wire 3 is passed by the cable 14, and is connected to the work piece 1 by the cable 15, and power for generating the arc 4 between the wire 3 and the work piece 1. Arc generating means for feeding 17 is a wire feeding means for feeding the wire 3 to the workpiece 1 through the torch 16, and 18 is a filler feeding means for feeding the filler 7 to the welding position of the workpiece 1 through the torch 19. is there. A heating unit 20 is connected to the torch 19 and the workpiece 1 by the cable 21 and the cable 22 and heats the filler 7 by supplying current to the filler 7. Reference numeral 23 denotes control means for controlling the laser generating means 9, the arc generating means 13, the filler feeding means 18, and the heating means 20.

  The laser generating means 9 condenses the laser beam 2 by the condensing optical system 12 and irradiates the work piece 1. The condensing optical system 12 may be composed of one or a plurality of lenses. The laser transmission means 11 may be an optical fiber or a transmission system combined with a lens. Although not shown, the laser oscillator 10 can freely control its output value and output timing by an external control device.

  The arc generating means 13 controls the wire feeding means 17 at the start of welding, and feeds the wire 3 toward the workpiece 1 while the wire 3 and the workpiece 1 are in contact with each other. The arc 4 is controlled to be generated. At the end of welding, the wire feeding means 17 stops feeding the wire 3 and controls the arc 4 to stop.

  The filler feeding means 18 or the wire feeding means 17 can freely control the feeding speed and the start and stop of feeding by an external control device. The heating means 20 can supply a predetermined current, and the current value and supply timing can be controlled by an external control device. The heating unit 20 may be, for example, a power source that supplies a constant direct current or a power source that supplies a pulsed current. Something like a TIG power supply may be used.

  During welding, the control unit 23 controls the heating unit 20 to supply a current for heating the filler 7. Although not shown, welding is performed while heating the filler 7 by bringing the filler 7 into contact with the workpiece 1 or the molten pool 6 and passing an electric current through the filler 7. As a result, the welding speed could be increased, and a wide allowable gap could be obtained in joint welding.

(Embodiment 1)
As shown in the above-mentioned reference example, in the laser welding method proposed by the inventor in the past, welding was performed while heating the filler, and the allowable gap for joint welding could be widened by increasing the welding speed.

  However, if there is a disturbance during welding, the filler tip moves away from the work piece or the molten pool, so the heating effect is lost, and a predetermined welding speed cannot be obtained. There is a possibility that it will be impossible to make. A more preferable configuration in which this point is improved will be described in detail in the first embodiment.

  FIG. 1 is a schematic diagram showing a configuration of a laser welding apparatus according to Embodiment 1 of the present invention. In addition, the same code | symbol is attached | subjected to the place which show | plays the same structure, operation | movement, and effect as the content shown to FIG. 3 and FIG. 4, detailed description is abbreviate | omitted, and it demonstrates centering on a different part.

  Reference numeral 24 denotes a voltage detection means for detecting a voltage that is connected to the torch 19 and the workpiece 1 and that is generated when the filler 7 is heated. Reference numeral 25 denotes adjustment means for adjusting the tip position of the filler 7 by attaching the torch 19 and adjusting the torch 19. The adjusting means 25 can adjust the torch 19 in the horizontal direction, vertical direction, or vertical direction of the paper.

  Reference numeral 26 denotes a control means for inputting and calculating a signal from the voltage detection means 24 and controlling the laser generation means 9, arc generation means 13, filler feeding means 18, heating means 20, and adjustment means 25. The control means 26 may use a computer, but may use components, devices, apparatuses, or combinations thereof having a calculation function such as a computer. As the control means 26, a robot may be used. In this case, although detailed description is omitted, the manipulator unit of the robot may be used instead of the adjusting means 25. Although not shown in the drawing, the control means 26 is the timing of welding start (arc start, laser irradiation start), the feed speed of the wire 3 or the filler 7 or the timing of changing it, the heating current of the filler 7 or the same. The timing to change can be controlled.

  The operation of the laser welding apparatus in the first embodiment of the present invention will be described. As shown in FIG. 1, the control means 26 controls the laser generating means 9 and the arc generating means 13 to irradiate the welding position of the workpiece 1 with the laser beam 2 or generate the arc 4 for welding. At the same time, the filler 7 is supplied to the welding position. The control means 26 operates to control the heating means 20 to supply a heating current for heating the filler 7 so as to increase the feeding speed of the filler 7. Further, the control means 26 inputs the voltage signal from the voltage detection means 24, calculates it, adjusts the adjustment means 25 according to the calculation result, and adjusts the tip position of the filler 7. Operate. The principle will be described with reference to FIG.

  FIG. 2 is a schematic diagram showing a contact state between the filler 7 and the molten pool 6. FIG. 2A shows a normal contact state, and FIG. 2B shows a disturbance state in which the filler 7 tends to leave the molten pool 6 due to the influence of the disturbance.

  In a normal state, there is a sufficient contact length L1 between the filler 7 and the molten pool 6, and heat concentration at the contact portion A is small. On the other hand, in the disturbance state, the filler 7 tends to move away from the molten pool 6, so that the contact length L2 between them becomes shorter than the contact length L1 in the normal state. For this reason, the cross-sectional area at the contact portion B is reduced and the electrical resistance is increased, so that heat concentration may occur at the contact portion B. If the concentration of heat in the contact portion B is too large, the temperature rise of the molten metal in this region becomes too high, and in some cases, there is a possibility that scattering accompanying boiling occurs. In actual welding, it is necessary to prevent this. That role is fulfilled by the control means 26.

  Specifically, in the disturbance state as shown in FIG. 2B, the current-carrying area at the contact portion B decreases and the temperature of the molten metal increases, so that the voltage drop during this period increases. This voltage drop signal is always detected by the voltage detection means 24 and input to the control means 26. Although not shown, the control means 26 compares the preset voltage drop reference value with the preset voltage drop reference value. When the voltage drop signal exceeds the reference voltage drop reference value, a disturbance is applied. Judged as a state. Thereafter, the control means 26 operates so as to make the disturbance state normal by any of the following operations.

  1) The adjusting means 25 is controlled to operate so that the tip of the filler 7 approaches the molten pool 6 by a predetermined value and the contact length L2 approaches L1.

  2) The filler feeding means 18 is controlled so as to increase the feeding speed of the filler 7 by a predetermined value so that the tip of the filler 7 approaches the molten pool 6.

  3) Perform both operations 1) and 2).

  During welding, the above operation is performed at a predetermined sampling period and control period, and the contact between the filler 7 and the molten pool 6 is maintained in a normal state.

  As described above, according to the laser welding apparatus in the first embodiment of the present invention, the filler is supplied to the welding position while simultaneously performing the laser welding and the arc welding performed by feeding the wire to the welding position of the workpiece. In the laser welding method, when the filler is brought into contact with the workpiece or the molten pool and a heating current is passed through the filler, a sign of poor contact between the filler and the workpiece or the molten pool is detected. Then, even if there is a disturbance during welding by performing welding while adjusting the feed speed of the filler or the tip position of the filler so that the filler and the workpiece or the molten pool are in contact with each other, Contact between the filler and the workpiece or the molten pool can be ensured, and a good weld bead can be obtained.

  As described above, the current used in the heating means 20 according to the first embodiment of the present invention is not particularly specified, but the filler 7 can be more effectively heated using the pulsed current.

  As described above, regarding the operation of the control unit 26 according to the first embodiment of the present invention, the disturbance state is determined based on the voltage drop signal detected by the voltage detection unit 24. Although not shown, a resistance signal is calculated from the heating current signal of the heating means 20 and the voltage drop signal, and the disturbance state is determined using either the resistance signal or the differential value of the resistance signal. Good. By doing so, it is possible to detect a disturbance state even when a pulsed current is used. Needless to say, a differential value of the voltage signal may be used.

  As described above, according to the present invention, in the laser welding method of supplying filler to the welding position while simultaneously performing laser welding and arc welding performed by feeding a wire to the welding position of the work piece, the filler And the welded object or the molten pool are brought into contact, and when a heating current is passed through the filler, if a precursor of poor contact between the filler and the welded object or the molten pool is detected, the filler and the molten pool Even if there is a disturbance during welding by adjusting the feeding speed of the filler or the tip position of the filler so that the workpiece or the molten pool is in contact, the filler and the workpiece or the molten pool are welded. It is possible to provide a laser welding method and a laser welding apparatus capable of ensuring contact with the laser beam and obtaining a good weld bead.

DESCRIPTION OF SYMBOLS 1 Workpiece 2 Laser beam 3 Wire 4 Arc 5 Droplet 6 Molten pool 7 Filler 8 Bead 9 Laser generating means 10 Laser oscillator 11 Laser transmission means 12 Condensing optical system 13 Arc generating means 14 Cable 15 Cable 16 Torch 17 Wire feed Feeding means 18 Filler feeding means 19 Torch 20 Heating means 21 Cable 22 Cable 23 Control means 24 Voltage detection means 25 Adjustment means 26 Control means A Contact part B Contact part L1 Contact length L2 Contact length

Claims (6)

A laser welding method for supplying a filler to the welding position while simultaneously performing laser welding and arc welding performed by feeding a wire to a welding position of a workpiece,
When a precursor of poor contact between the filler and the workpiece or the molten pool is detected when the filler is brought into contact with the workpiece or the molten pool and a heating current is passed through the filler, the filler is detected. Welding method in which welding is performed while adjusting the feeding speed of the filler or the tip position of the filler so that the workpiece and the weld pool are in contact with each other. The laser welding method according to claim 1, wherein a precursor of poor contact between the filler and the workpiece or the molten pool is detected by a voltage value between the filler and the workpiece or the molten pool. The laser welding method according to claim 1, wherein a precursor of poor contact between the filler and the workpiece or the molten pool is detected by a resistance value between the filler and the workpiece or the molten pool. Laser generating means for irradiating a welding position of a workpiece to be welded, wire feeding means for feeding a wire to the welding position, and an arc on the wire and the workpiece to be welded while controlling the wire feeding means An arc generating means for supplying electric power for welding, a filler feeding means for feeding a filler to the welding position, a heating means for passing an electric current through the filler, and between the filler and the workpiece Voltage detecting means for detecting a voltage; and control means for controlling the laser generating means, the arc generating means, and the heating means by inputting a detection signal of the voltage detecting means,
When the filler is heated by bringing the filler into contact with the workpiece or the molten pool and a heating current is passed through the filler, a sign of poor contact between the filler and the workpiece or the molten pool is detected. Then, the said control means is a laser welding apparatus which welds, adjusting the feed speed of the said filler, or the front-end | tip position of the said filler so that the said filler, the said to-be-welded object, or the said molten pool may contact. The laser welding apparatus according to claim 4, wherein a sign of poor contact between the filler and the workpiece or the molten pool is detected by a voltage value between the filler and the workpiece or the molten pool. The laser welding apparatus according to claim 4, wherein a sign of poor contact between the filler and the workpiece or the molten pool is detected by a resistance value between the filler and the workpiece or the molten pool.

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