JP4483362B2 - Laser hybrid arc welding system - Google Patents

Description

    The present invention relates to a laser hybrid arc welding machine and a laser hybrid arc welding system for welding workpieces using both an arc and a laser.

    In recent years, laser hybrid arc welding using both a laser and an arc welder has attracted attention. In this laser hybrid arc welding system, arc and laser outputs are simultaneously output to a workpiece for welding. A system in which a YAG laser or a semiconductor laser is used for the laser oscillator used for this and a pulse MIG welder is combined with the arc welder is common. This laser hybrid welding system is effective for deep penetration shape, improved welding speed, improved arc stability, improved bead appearance, etc. Attention has been paid.

As a conventional laser hybrid arc welding system, there is one that changes the laser output in synchronization with the pulse peak section of the pulse welder for the purpose of increasing the laser absorption efficiency and improving the welding stability in the base section ( For example, see Patent Document 1).
JP 2003-25081 A

    In the laser hybrid arc welding system described above, it is important that the target position of the welding wire on the workpiece and the target position (offset) of the laser are within a few mm.

    In such a laser hybrid arc welding system, the laser is applied to the workpiece and heat is applied to the workpiece. However, because the offset is close, depending on the construction conditions such as the droplet transfer status and workpiece shape, the welding wire tip can be used. The detached droplets and the laser may interfere with each other. At this time, the laser beam directly or reflected from the workpiece was irradiated to the droplet, and the applied heat applied explode the droplet and spattered into a fine spatter, which sometimes deteriorated the appearance of the bead.

    This phenomenon is remarkable at the time of construction using 5356 wires, and the frequency of occurrence decreases in the order of 4043 wires and 1100 wires. This is considered to be because the 5356 wire material contains more Mg than the 4043 wire and 1100 wire, and the boiling point of the wire is low. Inclusion of Mg is necessary to ensure the strength of the workpiece. If the above-mentioned droplet explosion occurs during construction using 5356 wire and the wire component is spattered, the Mg content in the workpiece decreases. As a result, the desired workpiece strength may not be ensured.

    In addition, during welding, the arc length may become extremely short depending on the construction state such as the state of droplet transfer and the workpiece shape. In that case, the laser beam directly or reflected from the workpiece may be irradiated to the tip of the welding wire, and the welding wire may be melted unnecessarily. Originally, melting of the welding wire is controlled by the waveform control sequence by the arc welder. Therefore, if unnecessary welding of the welding wire occurs due to laser interference as described above, it will be a disturbance that is not expected to be controlled. Caused unstable welding, resulting in poor welding and welding defects.

    Furthermore, in the laser hybrid arc welding system, the problem is that the cost of the laser equipment occupying the entire system is high, and there is a problem of improving the operating rate such as low cost equipment introduction and no line stoppage. .

    In order to solve the above-described problems, the present invention can detect a construction state such as an arc current, an arc voltage, and a molten pool image, and can control the laser output and the arc output according to each situation. The purpose of the present invention is to provide a laser hybrid arc welding machine and a laser hybrid arc welding system that can suppress the introduction cost of the laser.

    In order to solve the above-described problems, the laser hybrid welding system of the present invention observes a construction state such as an arc current, an arc voltage, and a molten pool image, detects a detachment state of a droplet, and the like according to each situation. A laser output control unit and an arc output control unit for controlling output and arc output are provided.

    And by this structure, the stable welding without a welding defect, the favorable bead appearance, and welding strength can be obtained. In addition, by providing a laser output switching machine that can superimpose or distribute the output of multiple laser oscillators to multiple laser hybrid arc welding systems, the introduction cost of the laser oscillator can be reduced, and the laser oscillator The operating rate can be increased.

    As described above, the present invention reduces the laser output to an appropriate value during the transfer of the droplet, thereby avoiding the interference between the transferred droplet and the laser, preventing the explosion of the droplet, Reduction, improvement of bead appearance, and work strength can be ensured. Further, when the arc length is shortened, the welding wire and the laser are prevented from interfering with each other, so that unnecessary welding wire melting can be avoided, welding stability can be improved, and welding defects can be prevented.

    In addition, the number of laser oscillators can be reduced by providing a laser output switching machine that superimposes and divides the output from multiple laser oscillators and switches to multiple laser heads, and introduces high-power lasers. Is no longer necessary. As a result, the facility introduction cost can be suppressed. Further, since the production line does not need to be stopped at the time of failure or maintenance, the operation rate is improved.

    Embodiments of the present invention will be described below.

    1 to 3 and 9 to 11, 1 is a laser output control unit, 2 is an arc output control unit, 3 is a construction state detector, 4 is an arc power supply unit, 5 a is a laser oscillator, 5 ′ is Second laser oscillator, 6 is a laser head, 6 'is a second laser head, 7 is a welding torch, 7' is a second welding torch, 8 is a workpiece, 8 'is a second workpiece, and 9 is a laser. A hybrid arc welder, 9 'is a second laser hybrid arc welder, 10 is a laser output switching machine, and 11 is a laser oscillator for laser hybrid arc welding.

4 to 7, in the figure, T1 is a predetermined first time, L1 is a predetermined first laser output value, L2 is a predetermined second laser output value, and E1 is a droplet detachment. At the time of detection, E2 is the time when the transition of the droplet to the molten pool is detected, E3 is the time when the predetermined first time T1 has elapsed since the laser output was changed to the predetermined first laser output value L1, E4 is a pulse base control start point, F1 is a predetermined first function, and F2 is a predetermined second function.

In FIG. 8, H1 is a predetermined first pulse frequency value, P1 is a predetermined first pulse peak value, B1 is a predetermined first pulse base value, and H2 is a predetermined second pulse frequency. , P2 is a constant second pulse peak value, B2 is a predetermined second pulse base value, VE1 is detected when the arc length is shortened, and VE2 has an appropriate arc length Indicates the time.
(Embodiment 1)
The operation of the laser hybrid arc welding system configured as shown in FIG. 1 will be described.

    In the following, an explanation will be given using an example in which a semiconductor laser is used as the laser oscillator and a consumable electrode type pulse MIG welder is used as the arc welder.

    The arc power supply unit 4 feeds the supplied input power between the welding torch 7 and the workpiece 8, and the arc is ignited between the tip of the welding wire and the workpiece 8 fed from the tip of the welding torch 7. I do. The input power supplied to the laser oscillator 5 is converted into a laser, transmitted to the laser head 6 via a transmission fiber, and laser welding is performed by irradiating the workpiece 8 with the laser from the laser head 6. The transmission path may be another optical system such as a mirror capable of transmitting light. At this time, it is important that the laser spot diameter is 2 mm or less. However, depending on the state of construction, this is not limited to the above, and it is effective to increase the spot diameter and lower the laser energy density when the machining accuracy of the workpiece is low and the target tolerance is required. The distance between the laser head 6 and the workpiece 8 is preferably 15 cm or more. This is to avoid interference with the workpiece 8 and to prevent damage to the laser head 6 from spatter, fumes and radiant heat around the workpiece 8. However, this is not limited to the above depending on the state of construction, and if the optical system (condensing lens) used for the laser head does not have a desired specification, the distance between the workpiece and the laser head may be unavoidable. Also, the laser irradiation position is preferably around the weld pool tip 2-3 mm ahead of the welding wire aiming position on the workpiece. However, depending on the construction state, this is not the case.

    Next, the construction state detector 3 will be described. The construction state detector 3 detects an arc current, an arc voltage, an arc power, a workpiece melting state, a welding wire protrusion length, an arc length, and a welding wire droplet transfer state, and a laser output control unit 1 and an arc output control unit 2. The construction state detection information is output to The arc current is measured using CT or the like. The arc voltage is measured with a voltmeter at any one of the measuring terminals such as the output terminal of the arc power source 4, the tip of the welding torch 6, the work 8, and the welding wire feed feeder. Arc power is measured with a power meter. The melted state of the workpiece, the welding wire protrusion length, the arc length, and the welding wire droplet transfer state are detected by image processing using a high-speed camera image, or calculated from the arc current and arc voltage.

Next, the laser output control unit 1 will be described. The laser output control unit 1 detects the moment when the droplets are detached from the welding wire tip from the construction state detection information input from the construction state detector 3. As a detection method, there are a method of capturing a rapid change in arc impedance from an arc current and an arc voltage, and a method of detecting a high-speed camera image on the work 8 by image processing.
As shown in FIG. 4, the laser output control unit 3 outputs a laser output control signal for changing the laser output to a predetermined first laser output value L1 from the time point E1 at which the detachment of the droplet is detected. Alternatively, as shown in FIGS. 2 and 5, a laser output control signal for changing the laser output to a predetermined first laser output value L1 by receiving a signal at the pulse base control start time point E4 from the arc power supply unit 4. Is output. The predetermined first laser output value L1 needs to be sufficiently lower than the predetermined second laser output value L2 that is the laser output during the main welding or 0 (laser oscillation off). The laser oscillator 5 outputs in accordance with the signal.

    Next, as shown in FIG. 4, the laser output control unit 1 changes the laser output to a predetermined second laser output value L2 from the time point E2 at which the transition of the droplet to the molten pool is detected. Alternatively, as shown in FIG. 6, the laser output is output to a predetermined second laser output value L2 after a predetermined first time T1 from a time point E1 when the previous separation is detected and changed to the predetermined laser output 1L1. To change. The predetermined first time T1 needs to be long enough to complete the transfer of the droplets, and may be about 2 ms if pulse welding is performed at a pulse frequency of 100 Hz. However, it is not limited to the above depending on the construction state.

    The value L2 of the predetermined second laser output needs to be a value that can provide a sufficient effect as laser hybrid arc welding. For example, when a workpiece of general-purpose 5000 series aluminum alloy A5052 plate thickness t2.0 mm is welded with φ1.2 diameter 5356 wire at an arc current of 180 A, a welding speed of 4.0 m / min, a spot diameter of 2 mm, and an offset of 2 mm, The value L2 of the second laser output is desirably 2.0 kW or more. However, this is not limited to the above depending on the construction.

    The value during the fluctuation of the laser output may change in a pulse shape as shown in FIG. 4, and, as shown in FIG. 7, a predetermined second value from the predetermined first laser output value L1. The predetermined first function F1 is transferred when the laser output is shifted to the value L2, and the predetermined first function F1 is transferred when the laser output is shifted from the predetermined second laser output value L2 to the predetermined first laser output value L1. The laser output may be in accordance with the second function F2. The predetermined first function F1 and the predetermined second function F2 may be linear functions having a slope of 4 kW / ms. However, it is not limited to the above depending on the construction state.

    As described above, by detecting the detachment of the droplets and controlling the laser output during the transition of the detachment of the droplets to be reduced or zero, the frequency of occurrence of interference between the laser and the droplets is reduced, causing interference. The effect at the time becomes weaker. Therefore, explosion of droplets during welding transfer is unlikely to occur, and a bead appearance with good spatter generation can be obtained.

    Next, the arc output control unit 2 will be described. As shown in FIG. 8, the arc output control unit 2 sets the pulse peak value to a predetermined first pulse peak value P1 from the arc power source unit 4 at the time point VE1 when the arc length is detected to be extremely short. The arc output control signal to be changed to is output. As a method for detecting the arc length, there are a method for detecting an abrupt decrease in voltage, an increase in the number of short circuits, a method by image processing, and the like. The arc power supply unit 4 performs an arc output according to the signal. The predetermined first pulse peak value P1 needs to be higher than the predetermined second pulse peak value P2, which is the pulse peak value during the main welding. For example, the value may be 10% higher than the value of the pulse peak during the main welding (for example, 350A when the value of the pulse peak during the main welding is 320A). As a result, the arc voltage increases and the arc length can be extended. By extending the arc length, interference between the laser and the wire tip can be avoided, and stable welding becomes possible.

    The above is an example in which only the pulse peak value is changed. However, any one or a plurality of values of the pulse base value, the pulse frequency value, and the pulse width value may be changed.

    Next, as shown in FIG. 8, the arc output control unit 2 changes the pulse peak value to a predetermined second pulse peak value P2 with respect to the welding power source from the time point VE2 when the arc length becomes appropriate. An arc output control signal is output. The arc power supply unit 4 performs an arc output according to the signal.

The above is an example in which a semiconductor laser is used for the laser oscillator 5, but the laser oscillator 5 may be a YAG laser, a CO 2 laser, or the like capable of laser oscillation. Further, although the consumable electrode type pulse MIG welding machine is used as the arc power source unit 4, the consumable electrode type pulse CO2 / MAG welding machine, the consumable electrode type CO2 / MAG / MIG welding machine, which can be arc welded, An electrode type AC pulse CO2 / MAG / MIG welding machine may be used.
(Embodiment 2)
The operation of the laser hybrid arc welding system configured as shown in FIG. 2 will be described.

    In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

    In FIG. 2, the laser output control unit 1 detects at least one set value of a set current, a set voltage, a wire feed speed, a shield gas type, a wire type, a wire diameter, a workpiece material, and a welding speed, and a construction state detection. The construction state detection information such as the arc current, arc voltage, and arc length detected by the unit 3 is input, and the predetermined first laser output value L1, the predetermined second laser output value L2 in FIGS. The first time T1, the predetermined first function F1, and the predetermined second function F2 are set. For example, in the case of the set current 180A, a table that sets the predetermined first time T1 to 2 ms may be used. Alternatively, a function expressed as “predetermined first time T1 = predetermined constant / arc current at time E1” may be used.

    In FIG. 2, the arc output control unit 2 includes at least one set value of a set current, a set voltage, a wire feed speed, a shield gas type, a wire type, a wire diameter, a workpiece material, and a welding speed, The construction state detection information such as the arc current, arc voltage, and arc length detected by the state detection unit 3 is input, and the predetermined first pulse peak value P1 and the predetermined second pulse peak value P2 in FIG. The first pulse base value B1, the predetermined second pulse base value B2, the predetermined first pulse frequency value H1, and the predetermined second pulse frequency value H2 are set. For example, in the case of construction of φ1.2 mm diameter 5356 wire and set current 180A, a condition table is set in which the predetermined first pulse peak value P1 is set to 350A and the predetermined second pulse peak value is set to 320A. Also good. Alternatively, it may be set by a function expressed as “predetermined first pulse peak value P1 = predetermined second pulse peak value P2 + predetermined coefficient × (set voltage−arc voltage)”.

As described above, when the arc length is shortened, by increasing the value of the pulse peak, the arc length can be kept appropriate, avoiding interference between the welding wire and the laser, and unnecessary welding wire melting. It is possible to avoid the improvement of welding stability and the occurrence of welding defects.
(Embodiment 3)
The operation of the laser hybrid arc welding system configured as shown in FIG. 3 will be described.

    In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

    In the configuration of FIG. 3, the laser hybrid arc welding system is composed of two laser oscillators 5, 5 ′ and two laser hybrid arc welders 9, 9 ′. You may be comprised from an oscillator and 2 or more units | sets or 1 laser hybrid arc welding machine. As shown in FIG. 3, the laser outputs of the laser oscillator 5 and the second laser oscillator 5 ′ are switched to the laser head 6 and the second laser head 6 ′ by the laser output switching machine 10. The switching method may be a method of switching by rotating the mirror physically, or a method of switching the fiber.

(Embodiment 4)
The operation of the laser hybrid arc welding system configured as shown in FIG. 9 will be described.

    In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

    FIG. 9 shows an example in which one laser oscillator 5 and two laser hybrid arc welders are combined.

    The two laser hybrid arc welders 9, 9 'weld the two workpieces 8, 8'. The laser output from the laser oscillator 5 is switched by the laser output switching machine 10, and when construction is performed by the laser head 6, the laser output is supplied to the laser head 6, and the second laser head 6 ′. When construction is performed, a laser output is supplied to the second laser head 6 ′. As a result, it is possible to construct two laser hybrid arc welding systems using one laser oscillator 5, and the introduction cost can be reduced as compared with the case where two laser oscillators are conventionally required. I can plan.

The above is based on the premise that the laser head 6 and the second laser head 6 ′ do not output laser simultaneously, but the laser output to the laser head 6 and the second laser head 6 ′ is pulsed during construction. By switching, it is also possible to perform construction at the same time. Further, the laser output can be simultaneously supplied to the two laser heads by dividing the laser output using a semiconductor element.
(Embodiment 5)
The operation of the laser hybrid arc welding system configured as shown in FIG. 10 will be described.

    In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

    FIG. 10 shows an example in which two laser oscillators and one laser hybrid arc welder are combined. In FIG. 10, the laser outputs of the laser oscillator 5 and the second laser oscillator 5 ′ are superposed and output to the laser head 6 depending on the construction situation, and cannot be obtained with one laser oscillator. Output can be obtained. As a result, it is not necessary to introduce high-cost laser oscillator equipment, which is expensive, and by combining existing laser oscillators, various constructions including high-power laser construction can be handled.

In addition, by preparing a spare laser oscillator in advance, even if one laser oscillator fails, the output of the spare laser oscillator is automatically switched, and the system (production line) Etc.) can be avoided. Further, it is not necessary to stop the system when the maintenance of the laser oscillator is performed.
(Embodiment 6)
The operation of the laser hybrid arc welding system configured as shown in FIG. 11 will be described.

In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 11 shows a laser oscillator 11 for laser hybrid arc welding including a construction state detector 3, a laser output controller 1, an arc output controller 2, and a laser oscillator that performs a laser output operation in accordance with a laser output control signal. 2 is an example of a laser hybrid arc welding system including an arc power supply unit 4 that performs an arc output operation according to an arc output control signal output from the laser oscillator for laser hybrid arc welding, a welding torch 7 and a laser head 6.

  According to the laser hybrid arc welding machine and the laser hybrid arc welding system of the present invention, stable welding without welding defects, good bead appearance and welding strength can be obtained, and the introduction cost of the laser oscillator can be suppressed. Since it is possible, it is useful industrially.

The figure which shows the whole structure in Embodiment 1 of this invention. The figure which shows the whole structure in Embodiment 2 of this invention. The figure which shows the whole structure in Embodiment 3 of this invention. The figure which shows the laser output control method of the laser welding system in this invention The figure which shows the laser output control method of the laser welding system in this invention The figure which shows the laser output control method of the laser welding system in this invention The figure which shows the laser output control method of the laser welding system in this invention The figure which shows the arc output control method of the laser welding system in this invention The figure which shows the whole structure in Embodiment 4 of this invention. The figure which shows the whole structure in Embodiment 5 of this invention. The figure which shows the whole structure in Embodiment 6 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser output control part 2 Arc output control part 3 Construction state detector 4 Arc power supply part 5 Laser oscillator 5 'Second laser oscillator 6 Laser head 6' Second laser head 7 Welding torch 7 'Second welding Torch 8 Work piece 8 ′ Second work 9 Laser hybrid arc welder 9 ′ Second laser hybrid arc welder 10 Laser output switching machine 11 Laser oscillator T1 for laser hybrid arc welding Predetermined first time L1 Predetermined first 1 Laser output value L2 Predetermined second laser output value E1 Time point when droplet detachment is detected E2 Time point when transition of droplet to molten pool is detected E3 Predetermined first laser output value L1 Time point E4 when a predetermined first time T1 has elapsed after changing the laser output E4 Pulse base control start time point F1 Predetermined first function F2 Predetermined second function H1 Predetermined first Pulse frequency value P1 Predetermined first pulse peak value B1 Predetermined first pulse base value H2 Predetermined second pulse frequency value P2 Predetermined second pulse peak value B2 Predetermined second Pulse base value VE1 When it is detected that the arc length has become shorter VE2 When the arc length becomes appropriate

Claims (2)

A construction state detector that monitors at least one construction state of arc current, arc voltage, arc power, workpiece melting state, welding wire protrusion length, arc length, welding wire droplet transfer state, and the construction state detector A laser output control unit that outputs a laser output control signal that controls the laser output and an arc that outputs a signal from the construction state detector and outputs an arc output control signal that controls the arc output A laser hybrid arc welding machine provided with an output control unit and an arc power source unit that performs an output operation according to the arc output control signal;
A welding torch for applying an arc output of the laser hybrid arc welder to a workpiece;
A laser oscillator that performs a laser output operation in accordance with a laser output control signal output by the laser hybrid arc welder;
A laser hybrid arc welding system provided with a laser head for irradiating a workpiece with the laser output of the laser oscillator,
Two laser oscillator and two laser heads provided, laser hybrid arc welding system in which a laser output switching unit for switching the laser output of the two laser oscillator to the two laser heads. A construction state detector that monitors at least one construction state of arc current, arc voltage, arc power, workpiece melting state, welding wire protrusion length, arc length, welding wire droplet transfer state, and the construction state detector A laser output control unit that outputs a laser output control signal that controls the laser output and an arc that outputs a signal from the construction state detector and outputs an arc output control signal that controls the arc output A laser hybrid arc welding machine provided with an output control unit and an arc power source unit that performs an output operation according to the arc output control signal;
A welding torch for applying an arc output of the laser hybrid arc welder to a workpiece;
A laser oscillator that performs a laser output operation in accordance with a laser output control signal output by the laser hybrid arc welder;
A laser hybrid arc welding system provided with a laser head for irradiating a workpiece with the laser output of the laser oscillator,
A plurality of laser oscillator and one laser head, the laser hybrid arc having a laser output switching unit for outputting from one laser oscillator is switched to either the laser output of the laser oscillator to the one laser head Welding system.