JP4772957B2 - Laser irradiation AC arc welding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a laser irradiation arc welding method for performing high-speed welding by irradiating a laser to an arc generating portion.
[0002]
[Prior art]
Laser welding using a YAG laser, a carbon dioxide laser, or the like is a heat source with a high energy density, so that high-speed welding can be performed over 2 [m / min] to about 8 [m / min]. However, in this laser welding, when there is any gap in the joint part in welding to a lap joint, a butt joint, etc., both ends of the joint part with a gap are melted because the beam spot of the laser irradiation part is small. I can't weld. Therefore, in laser welding, since it is necessary to make a state where there is no gap in the joint portion of the workpiece, the practical application range is very limited.
[0003]
As one method for solving the above-described problems of laser welding, a combined laser irradiation DC arc welding method using both laser irradiation and DC arc welding has been proposed. This welding method secures high-speed weldability by the above-mentioned high energy density heat source formed by laser irradiation, melts the joint part widely by a wide heat source formed by a DC arc, and gaps the welding wire. By filling the portion, good high-speed welding can be performed even on a joint portion having a gap. Hereinafter, an example of this laser irradiation DC arc welding method will be described as Prior Art 1. In the following description, the case where the welding speed is 2 [m / min] or higher is referred to as high-speed welding.
[0004]
[Prior art 1]
FIG. 2 is a configuration diagram of a welding apparatus for carrying out the laser irradiation DC arc welding method of Prior Art 1. Hereinafter, a description will be given with reference to FIG.
The laser oscillation device 6 is an oscillation device such as a YAG laser or a carbon dioxide gas laser, and irradiates the work piece 2 with a laser 31 via a laser torch 41. The DC arc welding power supply device 71 controls the rotation of the feeding roll 5 of the wire feeding device to feed the welding wire 1 through the welding torch 42 and also a DC arc between the welding wire 1 and the workpiece 2. The welding voltage Vw and the welding current Iw for generating 32 are output.
The position where the laser 31 is irradiated may be the arc generating part of the work piece 2 or its peripheral part, and any position on the front, rear, right side or left side of the arc generating part with reference to the welding direction. Good.
[0005]
FIG. 3 is a block diagram of the laser oscillation device 6 described above. Hereinafter, a description will be given with reference to FIG.
The output start circuit ST outputs an output start signal St for starting laser output. The output setting circuit PS outputs an output setting signal Ps for setting the laser output value [W]. When the output start signal St is input, the laser output control circuit ROC irradiates the workpiece with a laser beam via the laser torch 41 with the output value set by the output setting signal Ps.
[0006]
As described above, the laser irradiation DC arc welding method of the prior art 1 enables high-speed welding to a joint portion having a gap, but the gap allowable range is as small as about 0.3 [mm] or less. The practical application range of this welding method is quite limited. Therefore, an AC arc welding method, which is a welding method that generally has a large gap tolerance, will be described as Prior Art 2.
[0007]
[Prior Art 2]
FIG. 4 is a configuration diagram of a welding apparatus for carrying out the AC arc welding method of Prior Art 2. In the figure, the same components as those in FIG. 2 described above are denoted by the same reference numerals, and description thereof is omitted. Hereinafter, an AC arc welding power supply 72 different from FIG. 2 will be described with reference to FIG. Here, the case where AC arc welding is AC pulse arc welding is illustrated.
[0008]
The AC arc welding power supply 72 controls the feeding of the welding wire 1 and re-ignites the arc by applying a re-ignition voltage at the time of polarity switching, as described later with reference to FIG. A welding voltage Vw and a welding current Iw for generating an AC arc 33 that alternately repeats the negative polarity of the electrode are output.
[0009]
FIG. 5 is a current / voltage waveform diagram showing the output waveform of the AC arc welding power supply 72 described above. FIG. 4A shows the time change of the welding current Iw, and FIG. 4B shows the time change of the welding voltage Vw. Hereinafter, a description will be given with reference to FIG.
[0010]
(1) Period from time t1 to t2 (peak period Tp)
During this period, the welding wire serves as an anode and the electrode has a positive polarity (EP) where the work piece serves as a cathode, and as shown in FIG. A predetermined peak current Ip is applied. Further, as shown in FIG. 5B, the welding voltage Vw during this period is the peak voltage Vp corresponding to the energization of the peak current Ip.
[0011]
(2) Period from time t2 to t3 (electrode minus period Ten)
When the electrode positive polarity (EP) is switched to the electrode negative polarity (EN) at the time t2, as shown in FIG. 5A, a predetermined amount that does not cause droplet transfer during a predetermined electrode negative period Ten is predetermined. The negative electrode current Ien is applied. Further, as shown in FIG. 5B, the welding voltage Vw during this period becomes the electrode minus voltage Ven corresponding to the energization of the electrode minus current Ien. In addition, when the polarity is switched at the time t2, the arc of the electrode positive polarity once disappears. Therefore, in order to re-ignite the arc with the electrode minus polarity, as shown in FIG. It is necessary to apply the re-ignition voltage Vrs between the welding wire (−) and the workpiece (+) for only a short time.
[0012]
(3) Period from time t3 to t4 (base period Tb)
When switching from negative electrode polarity (EN) to positive electrode polarity (EP) at time t3, as shown in FIG. 5A, a predetermined base that does not cause droplet transfer during a base period Tb described later The current Ib is energized. In addition, as shown in FIG. 5B, the welding voltage Vw during this period is the base voltage Vb corresponding to the energization of the base current Ib. At the end point (time t4) of the base period Tb, the average value of the welding voltage Vw (peak voltage Vp and base voltage Vb) during the electrode positive polarity period is a predetermined voltage setting value shown in FIG. It is automatically determined by being controlled to be equal to Vs.
Further, as described above, even when the polarity is switched at the time t3, the arc having the negative polarity of the electrode is once extinguished, so that the arc can be re-ignited with the positive polarity of the electrode as shown in FIG. It is necessary to apply a re-ignition voltage Vrs of about [V] between the welding wire (+) and the work piece (−) for only a short time.
[0013]
In the above-mentioned AC arc welding method, the heat input to the work piece and the amount of wire melt can be precisely controlled by controlling the time ratio between the electrode positive polarity and the electrode negative polarity. The tolerance is increased.
[0014]
FIG. 6 is a block diagram of the AC arc welding power supply 72 described above. Hereinafter, each circuit block will be described with reference to FIG.
The commercial power source AC is an input power source for the welding power source, and usually three-phase 200/220 [V] is often used. The output control circuit INV includes a primary side rectifier circuit that rectifies the commercial power supply AC, a smoothing circuit that smoothes the rectified rippled voltage, an inverter circuit that converts the smoothed DC voltage into high-frequency AC, The inverter circuit includes a plurality of sets of power transistor drive circuits and a PWM control circuit that performs PWM control of the inverter circuit using an error amplification signal Ea described later as an input signal.
[0015]
The high frequency transformer INT steps down the high frequency alternating current to a voltage value suitable for an arc load. The secondary side rectifiers D2a to D2d rectify the stepped-down high-frequency alternating current into direct current. The polarity switching drive circuit DR outputs the electrode minus polarity drive signal Nd (High level) when an electrode minus period signal Ten described later is input (High level), and does not input (Low level). ) Outputs the electrode positive polarity drive signal Pd (High level). Accordingly, when the electrode negative polarity drive signal Nd is output, the electrode positive polarity drive signal Pd is not output. Conversely, when the electrode negative polarity drive signal Nd is not output, the electrode positive polarity drive signal Pd is output. They are in a logically inverted relationship. The electrode positive polarity transistor PTR is turned on when the electrode positive polarity drive signal Pd is output, and the output of the welding power source device is in the electrode positive polarity period. On the other hand, the electrode negative polarity transistor NTR is turned on when the electrode negative polarity drive signal Nd is output, and the output of the welding power source device is in the electrode negative polarity period.
[0016]
The reactor WL smoothes the rippled output for energizing the electrode positive polarity transistor PTR or the electrode negative polarity transistor NTR and supplies the smoothed output to the AC arc 33. The above-described peak current Ip and base current Ib during the electrode positive polarity period shown in FIG. 5 are energized through the route of D2a or D2b → PTR → WL → welding wire 1 → workpiece 2. On the other hand, the electrode minus current Ien during the electrode minus polarity period is energized through a path of the workpiece 2 → welding wire 1 → WL → NTR → D2c or D2d.
[0017]
The re-ignition voltage application circuit VRS receives an electrode minus period signal Ten, which will be described later, as an input, and at the rise of the electrode minus period signal Ten corresponding to the switching from the electrode plus polarity to the electrode minus polarity and from the electrode minus polarity to the electrode plus. When the electrode minus period signal Ten corresponding to the switching to the polarity falls, the re-ignition voltage Vrs is output.
[0018]
The peak period timer circuit TP outputs a peak period signal Tp that is at a high level for a predetermined period, triggered by the input of a comparison signal Cm (to be described later) (High level). The electrode minus period timer circuit TEN outputs an electrode minus period signal Ten that is at a high level for a predetermined period, triggered by the end (falling) of the peak period signal Tp.
[0019]
The voltage detection circuit VD detects the welding voltage Vw and outputs a voltage detection signal Vd. The voltage setting circuit VS outputs a voltage setting signal Vs that is a target value of the average value of the welding voltages (the peak voltage Vp and the base voltage Vb in FIG. 5 described above) during the electrode positive polarity period. The comparison circuit CM receives the voltage detection signal Vd, the voltage setting signal Vs, and the electrode minus period signal Ten as an input, and the voltage during the period when the electrode minus period signal Ten is not input (electrode plus polarity period). When the average value of the detection signal Vd becomes equal to the voltage setting signal Vs (time t4 in FIG. 5 described above), the comparison signal Cm that is at a high level for a short time is output. The comparison circuit CM described above when the average value of the voltage detection signal Vd during the electrode positive polarity period from the output start time of the peak period signal Tp becomes equal to the voltage setting signal Vs. It becomes a trigger signal for the peak period timer circuit TP to start outputting again.
[0020]
The peak current setting circuit IP outputs a predetermined peak current setting signal Ip that causes droplet transfer. The electrode minus current setting circuit IEN outputs a predetermined electrode minus current setting signal Ien that does not cause droplet transfer. The base current setting circuit IB outputs a predetermined base current setting signal Ib that does not cause droplet transfer. The peak period switching circuit SP is switched to the a side when the above-described peak period signal Tp is input (at the high level), and outputs the peak current setting signal Ip as the current control setting signal Isc. When it is not (Low level), it is switched to the b side and a switching setting signal Se described later is output as a current control setting signal Isc. The electrode minus period switching circuit SE is switched to the a side when the above-described electrode minus period signal Ten is input (at the high level), and outputs the electrode minus current setting signal Ien as the switching setting signal Se. When the signal is not input (at the low level), it is switched to the b side and the base current setting signal Ib is output as the switching setting signal Se.
The peak period switching circuit SP and the electrode minus period switching circuit SE are configured to set the peak current setting signal Ip when the peak period signal Tp is input, and set the electrode minus current when the electrode minus period signal Ten is input. When neither the period signal Tp nor Ten is input, the base current setting signal Ib is output as the current control setting signal Isc.
[0021]
The current detection circuit ID detects an AC welding current Iw and outputs a current detection signal Id obtained by converting the value into an absolute value. The error amplification circuit EA amplifies an error between the current detection signal Id and the current control setting signal Isc, and outputs an error amplification signal Ea. By this error amplification signal Ea, the output control circuit INV controls the energization value of the welding current Iw as described above. Therefore, the peak current Ip is energized when Isc = Ip, the electrode minus current Ien is energized when Isc = Ien, and the base current Ib is energized when Isc = Ib.
[0022]
FIG. 7 is a timing chart of each signal in the AC arc welding power supply 72 described above. FIG. 4A shows the time change of the welding current Iw, FIG. 3B shows the time change of the welding voltage Vw, and FIG. 4C shows the time change of the peak period signal Tp. (D) shows the time change of the electrode minus period signal Ten, and (E) shows the time change of the comparison signal Cm. FIGS. 5A and 5B are the same as FIG. 5 described above. Hereinafter, a description will be given with reference to FIG.
[0023]
(1) Period from time t1 to t2 (peak period Tp)
During this period, since the electrode minus period signal Ten shown in FIG. 4D is not output (Low level), the electrode plus polarity drive signal Pd of the polarity switching drive circuit DR described above is outputted and the electrode plus polarity transistor is output. The PTR is turned on and the output is in the electrode positive polarity period. Further, as shown in FIG. 6C, the peak period signal Tp is output (High level), so that the peak current Ip is energized as shown in FIG. As shown, the welding voltage Vw becomes the peak voltage Vp.
[0024]
(2) Period from time t2 to t3 (electrode minus period Ten)
During this period, since the electrode minus period signal Ten shown in FIG. 4D is output (High level), the electrode minus polarity drive signal Nd of the polarity switching drive circuit DR described above is outputted and the electrode minus polarity transistor is output. The NTR is turned on and the output is in the electrode negative polarity period. At the same time, since the electrode minus period signal Ten is output, the electrode minus current Ien is energized as shown in FIG. 5A, and the welding voltage Vw is equal to the electrode minus voltage Ven as shown in FIG. Become.
Further, as described above, at the time t2 when the electrode minus period signal Ten shown in FIG. 4D rises and at the time t3 when it falls, the re-ignition voltage Vrs is applied as shown in FIG.
[0025]
(3) Period from time t3 to t4 (base period Tb)
During this period, since the electrode minus period signal Ten shown in FIG. 4D is not output (Low level), the electrode has a positive polarity as in the period (1). During this period, neither the peak period signal Tp shown in FIG. 5C nor the electrode minus period signal Ten shown in FIG. 4D is output (Low level). As shown, the base current Ib is energized, and the welding voltage Vw becomes the base voltage Vb as shown in FIG.
As described above, since the average value of the welding voltage detection signal Vd and the value of the voltage setting signal Vs during the electrode positive polarity period become equal at time t4, the comparison signal Cm is short as shown in FIG. The time period becomes the high level, and when this is triggered, the peak period signal Tp shown in FIG. 4C starts to be output, and the operation of the above item (1) is performed again.
[0026]
[Problems to be solved by the invention]
As described above, in the laser irradiation DC arc welding method of the prior art 1, high-density energy heat input by laser irradiation, wide melting of the joint portion by a heat source with a DC arc spread, and filling of the welding wire in the gap portion are performed. High-speed welding to a joint portion having a very small gap of about 0.3 [mm] or less is possible. However, since the practical application is considerably limited with a very small gap tolerance as described above, it has been a problem to increase the gap tolerance during high-speed welding.
[0027]
On the other hand, as described above, the AC arc welding method of the prior art 2 has a large gap tolerance range because the heat input to the work piece and the wire melting amount can be precisely controlled. However, only with a heat source having an AC arc spread, there is a limit to the amount of heat input to the workpiece, so that welding can be performed only when the welding speed is about 2 [m / min] or less.
[0028]
Furthermore, in the welding method of the prior art 2, as described above, a high re-ignition voltage of about 300 [V] is applied to re-ignite the arc when switching the polarity. However, by applying this high re-ignition voltage, the re-ignition position of the arc on the workpiece may not be a short distance (target welding position) from the wire tip but a position away from it. . In such a case, the arc is re-ignited once at the time of polarity switching, but when the re-ignition voltage is applied, the long arc length cannot be maintained and an arc break occurs (hereinafter referred to as this). This phenomenon is called arc break after re-ignition). The cause of this arc break is that it is necessary to apply a high re-ignition voltage of about 300 [V] in order to ensure re-ignition, while application of such a high re-ignition voltage. Therefore, as described above, the re-ignition position is often formed at a distant position, and as a result, an arc break occurs. If an arc break occurs during welding, a weld defect such as a poor bead appearance or poor penetration occurs.
[0029]
Therefore, in the present invention, it is possible to perform good high-speed welding of 2 [m / min] or more on the joint portion having a large gap, and the arc is re-ignited smoothly, and the re-ignition is performed. Provided is a laser-irradiated AC arc welding method that does not cause subsequent arc breakage.
[0030]
[Means for Solving the Problems]
  According to the first aspect of the present invention, an AC arc welding is performed in which a consumable electrode is fed to a workpiece and an AC arc that alternately repeats the positive electrode polarity and the negative electrode polarity is generated between the consumable electrode and the workpiece. In the method
  A laser with a predetermined high output during a predetermined irradiation time from immediately before switching the polarity of the AC arc to the arc generating part of the workpiece or its peripheral part, and with a predetermined low output during other periods. To increase the temperature of the workpiece and the tip of the welding wire adjacent to the workpiece and smoothly re-ignite the arc when switching the polarity of the AC arc without applying a re-ignition voltage. This is a laser irradiation AC arc welding method to be performed.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
An example of an embodiment of the present invention is shown in FIG. 1 (the same diagram as FIG. 8),
In the AC arc welding method of feeding the consumable electrode 1 to the work piece 2 and welding by generating an AC arc 33 between the consumable electrode and the work piece and alternately repeating the electrode positive polarity and the electrode negative polarity,
By irradiating the arc generating portion of the workpiece 2 or its peripheral portion with a laser 31, the temperature of the workpiece 2 and the tip of the welding wire 1 adjacent thereto is raised, and the re-ignition voltage Vrs is set. This is a laser irradiation AC arc welding method in which re-ignition of the arc at the time of switching the polarity of the AC arc 33 is performed smoothly by applying a re-ignition voltage LVrs of a low voltage value without application.
[0035]
【Example】
[Example 1]
  The invention of Example 1 isIn the consumable electrode alternating current arc welding method in which the electrode positive polarity and the electrode negative polarity are alternately repeated, by irradiating a laser to the arc generation part of the work piece or its peripheral part, the work piece and the welding wire adjacent thereto are irradiated. TipIncrease the temperature,A laser irradiation re-ignition voltage non-applied AC arc welding method that smoothly performs re-ignition without applying a re-ignition voltage when switching the polarity of the AC arc. Hereinafter, the invention of Example 1 will be described with reference to FIGS.
[0036]
FIG. 8 is a configuration diagram of a welding apparatus for carrying out the laser irradiation re-ignition voltage non-applied AC arc welding method of the first embodiment. In the figure, the same components as those shown in FIG. 2 or FIG. Hereinafter, a re-ignition voltage non-applied AC arc welding power supply device 73 different from FIG. 2 or FIG. 4 will be described with reference to FIG. In addition, the case where alternating current arc welding is alternating current pulse arc welding is illustrated similarly to the time of FIG.
[0037]
The re-ignition voltage non-applied AC arc welding power supply device 73 controls the feeding of the welding wire 1 and, as will be described later with reference to FIG. 10, does not apply the re-ignition voltage Vrs at the time of polarity switching. The welding current Iw and the welding voltage Vw are generated to generate the AC arc 33 that causes the arc to be smoothly re-ignited and that alternately repeats the electrode positive polarity and the electrode negative polarity without causing arc break after re-ignition. To do.
[0038]
FIG. 9 is a block diagram of the re-ignition voltage non-applied AC arc welding power supply device 73 described above with reference to FIG. In the figure, as described above, the re-ignition voltage application circuit VRS described above with reference to FIG. 6 is not required because no re-ignition voltage is applied during polarity switching, and the other circuit blocks are the same as those in FIG. Therefore, the description thereof is omitted.
[0039]
FIG. 10 is a diagram showing the relationship between the welding current / voltage waveform and the AC arc generation state in Example 1 described above. FIG. 4A shows the change over time of the welding current Iw, FIG. 4B shows the change over time of the welding voltage Vw, and FIGS. 4C1 to 3C3 show the laser irradiation part and the AC arc. The time change of the state of a generation | occurrence | production part is shown. Hereinafter, a description will be given with reference to FIG.
[0040]
(1) When switching polarity at time t2.
When the polarity is switched from the positive electrode polarity (EP) to the negative electrode polarity (EN) at time t2, the negative electrode arc is re-ignited without applying the re-ignition voltage Vrs as shown in FIG. To do. The arc generation state at this time is shown in FIG. Hereinafter, a description will be given with reference to FIG.
As shown in the figure (C1), the welding wire 1 becomes a cathode (-) and a cathode spot is formed, and the workpiece 2 becomes an anode and an anode spot is formed. The cathode spot has the property that it is not easily formed because it requires energy to emit electrons. For this purpose, in the prior art 2, the cathode spot is formed by applying a high re-ignition voltage Vrs. On the other hand, in this invention, the temperature of the front-end | tip part of the to-be-welded object 2 and the welding wire 1 adjacent to it is raised by irradiating the arc generation part or its peripheral part with the laser 31. Since electrons are likely to be emitted when the temperature of the wire tip becomes high, the cathode spot is easily formed at the wire tip without applying the re-ignition voltage Vrs.
[0041]
On the other hand, since the anode point is on the side for accepting electrons, it has the property of being easily formed. Therefore, an anode point is formed at a welding target position where the distance between the wire tip and the workpiece 2 is the shortest in the feeding direction of the welding wire 1. As described above, the cathode spot and the anode spot are formed, and the negative electrode AC arc 33 is smoothly re-ignited without applying the re-ignition voltage Vrs.
[0042]
(2) Period from time t2 to t3 (electrode minus period Ten)
During this period, the electrode minus bulb Ien is energized as shown in FIG. 5A, and the welding voltage Vw becomes the electrode minus voltage Ven as shown in FIG. When the polarity is switched from the negative electrode polarity (EN) to the positive electrode polarity (EP) at time t3, the positive electrode arc is re-ignited without applying the re-ignition voltage Vrs as shown in FIG. To do. The arc generation state at this time is shown in FIG. Hereinafter, a description will be given with reference to FIG.
As shown in FIG. 2C2, the welding wire 1 becomes an anode (+) and an anode spot is formed, and the workpiece 2 becomes a cathode (−) and a cathode spot is formed. As described above, since the formation of the cathode spot is not easy, the prior art 2 forms the cathode spot by applying a high re-ignition voltage Vrs. On the other hand, in this invention, the temperature of the front-end | tip part of the to-be-welded object 2 and the welding wire 1 adjacent to it is irradiated by irradiating the arc generation part or its peripheral part with the laser 31. Since the electron is easily emitted when the workpiece 2 becomes high temperature, the cathode spot is smoothly formed in the laser irradiation of the workpiece 2 without applying the re-ignition voltage Vrs.
[0043]
On the other hand, as described above, the anode spot is formed at the tip of the welding wire 1 because the anode spot is easily formed. As described above, the cathode spot and the anode spot are formed, and the electrode positive polarity AC arc 33 is smoothly re-ignited without applying the re-ignition voltage Vrs.
[0044]
(3) Period from time t3 to t4 (base period Tb)
During this period, the base current Ib is energized as shown in FIG. 5A, and the welding voltage Vw becomes the base voltage Vb as shown in FIG. Further, during this period, the droplet does not normally transfer.
[0045]
(4) Period from time t4 to t5 to t6 (peak period Tp)
During the period from time t4 to t6, the peak current Ip is energized as shown in FIG. 9A, and the welding voltage Vw is the peak voltage Vp as shown in FIG. At time t5, as shown in FIG. 3C3, the tip of the wire is melted by the application of a large peak current Ip and the droplet moves, and the cathode spot is set so that the arc length is minimized. The formation position may move from the laser irradiation part to the welding target position. Conversely, the cathode spot may not move during this period depending on the setting of the surface condition of the work piece, laser output value, peak current value Ip, and the like. In either case, there is no effect on the welding quality.
[0046]
In the welding method of Example 1 described above, high-speed welding is possible by laser irradiation, a large gap is allowed by an AC arc, and the arc can be smoothly re-applied without applying a re-ignition voltage by laser irradiation. It can be ignited and arc break after re-ignition does not occur. Therefore, good high-speed welding can be performed on a joint portion having a large gap.
[0047]
[Example 2]
  The invention of Example 2 isIn the consumable electrode AC arc welding method in which the electrode positive polarity and the electrode negative polarity are alternately repeated, the welding object 1 and the welding wire 1 adjacent thereto are irradiated by irradiating a laser to the arc generating part or the peripheral part thereof. And a low re-ignition voltage LVrl of 50 [V] or more and 150 [V] or less, which is less than half that of the prior art 2, is applied at the time of switching the polarity of the AC arc, This is a laser irradiation low re-ignition voltage application AC arc welding method for smoothly performing arc re-ignition. The invention of Example 2 will be described below.
[0048]
The construction of the welding apparatus for carrying out the laser irradiation low re-ignition voltage application AC arc welding method of Example 2 will be described later with reference to FIG. It becomes the structure replaced with the low re-ignition voltage application AC arc welding power supply device.
FIG. 11 is a block diagram of the low re-ignition voltage application AC arc welding power source apparatus. The circuit configuration in FIG. 6 is a configuration in which the re-ignition voltage application circuit VRS in FIG. 6 described above is replaced with a low re-ignition voltage application circuit LVR, and other circuit blocks are the same. The low re-ignition voltage application circuit LVR receives the electrode negative period signal Ten as an input, and at the rising of the electrode negative period signal Ten corresponding to the switching from the electrode positive polarity to the electrode negative polarity and from the electrode negative polarity to the electrode positive. When the electrode minus period signal Ten corresponding to the switching to the polarity falls, the low re-ignition voltage LVrs of 50 [V] or more and 150 [V] or less is applied.
[0049]
In the welding method of the second embodiment described above, by applying the low re-ignition voltage LVrs, the temperature increase due to the low re-ignition voltage LVrs and the laser irradiation can be achieved even when the laser irradiation position is away from the arc generating portion. Due to the synergistic effect of both actions, the re-ignition of the arc is carried out smoothly and the applied re-ignition voltage value is less than half that of the prior art 2, so that arc break after re-ignition also occurs. do not do. Here, the reason why the lower limit value of the low re-ignition voltage LVrs is 50 [V] is that the no-load voltage value of the welding voltage Vw is about 50 to 80 [V], and the lower re-pointing voltage is lower than that. This is because the above effect is not obtained even when an arc voltage is applied. On the other hand, the reason why the upper limit value of the low re-ignition voltage LVrs is 150 [V] is that when a re-ignition voltage higher than this is applied, arc break after re-ignition occurs as described above. is there.
[0050]
[Example 3]
  The invention of Example 3 isThe output synchronization for smoothly performing the re-ignition of the arc by performing the laser irradiation in the first and second embodiments described above for a predetermined irradiation time Ta immediately before switching the polarity of the AC arc. This is a laser-irradiated AC arc welding method. That is, in the inventions of the first and second embodiments, the laser is continuously irradiated, but in the invention of the third embodiment, the laser is irradiated intermittently for the irradiation time Ta described above. The invention of Example 3 will be described below.
[0051]
FIG. 12 is a configuration diagram of a welding apparatus for carrying out the output synchronous laser irradiation AC arc welding method of the third embodiment. In the configuration shown in FIG. 8, the re-ignition voltage non-applied AC arc welding power source 73 in FIG. 8 is replaced with an output synchronous AC arc welding power source 74 described later in FIG. 12, and the laser oscillation device 6 is replaced with FIG. The irradiation time for synchronizing the polarity switching of the AC arc and the laser irradiation from the output synchronous AC arc welding power source 74 to the output synchronous laser oscillation device 61 instead of the output synchronous laser oscillation device 61 described later in FIG. In this configuration, the signal Ta is output. Hereinafter, both apparatuses will be described.
[0052]
FIG. 13 is a block diagram of the output synchronous AC arc welding power supply 74 described above. In the figure, the same circuit blocks as those in FIG. 9 described above are denoted by the same reference numerals, and description thereof is omitted. Hereinafter, the electrode plus irradiation start timer circuit TPA, the electrode minus irradiation start timer circuit TEA, and the irradiation time timer circuit TA surrounded by dotted lines, which are circuit blocks different from those in FIG. 9, will be described.
[0053]
The electrode plus irradiation start timer circuit TPA outputs an electrode plus irradiation start signal Tpa that is at a high level for a predetermined period, triggered by the end of output of the peak period signal Tp (change from high level to low level). The time length of the above-described electrode plus irradiation start signal Tpa so that the end point of the output of the electrode plus irradiation start signal Tpa is a point of time preceding the polarity switching point from the electrode plus polarity to the electrode minus polarity by the preceding time Tpb. Set the size.
The electrode minus irradiation start timer circuit TEA outputs an electrode minus irradiation start signal Tea that is at a high level for a predetermined period, triggered by the end of output of the electrode minus period signal Ten (change from high level to low level). The time length of the above-described electrode minus irradiation start signal Tea is such that the end point of the output of the electrode minus irradiation start signal Tea is a time point preceding the polarity switching point from the electrode minus polarity to the electrode plus polarity by the preceding time Tb. Set the size.
The irradiation time timer circuit TA outputs an irradiation time signal Ta that is at a high level for a predetermined period, triggered by the output end of both the electrode plus irradiation start signal Tpa and the electrode minus irradiation start signal Tea. This signal Ta is input to the output synchronous laser oscillation device 61.
[0054]
FIG. 14 is a block diagram of the output synchronous laser oscillation device 61 described above with reference to FIG. The circuit block shown in the figure is different from the circuit block shown in FIG. 3 only in the output synchronization start circuit STA, and will be described below.
The output synchronization start circuit STA outputs the output start signal St only while the irradiation time signal Ta from the above-described output synchronous AC arc welding power supply 74 is being output (High level). As a result, the laser is irradiated in synchronization with the irradiation time signal Ta.
[0055]
FIG. 15 is a timing chart of each signal in the output synchronous AC arc welding power supply 74 and the output synchronous laser oscillation device 61 described above. FIG. 4A shows the time change of the welding current Iw, FIG. 3B shows the time change of the welding voltage Vw, and FIG. 4C shows the time change of the peak period signal Tp. (D) shows the time change of the electrode minus period signal Ten, (E) shows the time change of the electrode plus irradiation start signal Tpa, and (F) shows the electrode minus irradiation. FIG. 4G shows the time change of the irradiation time signal Ta, and FIG. 4H shows the time change of the output start signal St of the output synchronous laser oscillation device 61. FIG. Show. Since FIGS. 7A to 7D are the same as FIG. 7 described above, description thereof is omitted. Hereinafter, FIGS. 5E to 5H will be described.
[0056]
(1) At time t1, as shown in FIG. 6C, triggered by the output of the peak period signal Tp, the electrode plus irradiation start signal Tpa is generated at time t11 as shown in FIG. Until the electrode plus irradiation start time Tpa is reached (High level). As described above in the description of FIG. 13, the above-described electrode plus irradiation start time Tpa is equal to Tp according to the preceding time Tb and the peak period Tp that are set in advance to irradiate the laser immediately before the polarity switching at time t2. -Tb is set.
[0057]
(2) At time t2, as shown in FIG. 4D, triggered by the output of the electrode minus period signal Ten, the electrode minus irradiation start signal Tea becomes time as shown in FIG. It is output (High level) during the electrode minus irradiation start time Tea up to t22. As described above in the description section of FIG. 13, the above-described electrode minus irradiation start time Tea is determined by the preceding time Tb and the electrode minus period Ten that are set in advance to irradiate the laser immediately before the polarity switching at time t3. It is set to be Ten-Tb.
[0058]
(3) As shown in FIG. 5G, the irradiation time signal Ta is output for a predetermined irradiation time Ta triggered by the fall of the electrode plus irradiation start signal Tpa or the electrode minus irradiation start signal Te. (High level). Therefore, the irradiation time signal Ta is output during both periods t11 to t21 and t22 to t31 before and after the polarity switching. Then, as shown in FIG. 5G, the output start signal St is also output (High level) in both the above periods, and the laser is irradiated during these periods.
[0059]
In the welding method of Example 3 described above, the arc can be smoothly re-ignited by irradiating the laser during the irradiation time before and after the polarity change, and the arc break after the re-ignition also occurs. do not do.
[0060]
[Example 4]
  The invention of Example 4 isIn the first and second embodiments described above, the laser is irradiated at a predetermined high output for a predetermined irradiation time Ta immediately before the switching of the polarity of the AC arc, and the predetermined low power is output during the other periods. This is a high and low power synchronous laser-assisted AC arc welding method in which a re-ignition of an arc is smoothly performed by irradiating a laser with an output. That is, in the invention of Example 1 and Example 2, the laser is continuously irradiated, and in the invention of Example 3, the laser is intermittently irradiated only during the irradiation time Ta described above. In the invention of 4, the laser is irradiated with a high output during the irradiation time Ta as described above, and the laser is irradiated with a low output during the other periods. The invention of Example 4 will be described below.
[0061]
A welding apparatus for carrying out the high-low power synchronous laser irradiation AC arc welding method of the fourth embodiment. In FIG. 12, only the output synchronous laser oscillation device 61 is replaced with a high and low output synchronous laser oscillation device 62 described later with reference to FIG. Accordingly, the other components, such as the output synchronous AC arc welding power source 74, are the same and will not be described. Hereinafter, the high-low output synchronous laser oscillation device 62 different from that shown in FIG. 12 will be described.
[0062]
FIG. 16 is a block diagram of the high-low power synchronous laser oscillation device 62 described above. In the figure, the same circuit blocks as those in FIG. 3 described above are denoted by the same reference numerals, and description thereof is omitted. Hereinafter, the high output setting circuit HPS, the low output setting circuit LPS, and the output setting switching circuit SPS different from those in FIG. 3 will be described.
[0063]
The high output setting circuit HPS outputs a high output setting signal HPs for setting a high output value [W] of the laser. The low output setting circuit LPS outputs a low output setting signal LPs for setting a low output value [W] of the laser. The output setting switching circuit SPS switches to the a side and outputs the high output setting signal HPs when the irradiation time signal Ta from the above-described output synchronous AC arc welding power supply 74 is inputted (when at the high level). When the irradiation time signal Ta is not input (at the low level), it is output as the setting signal Ps and switched to the b side, and the low output setting signal LPs is output as the output setting signal Ps.
[0064]
FIG. 17 is a timing chart of each signal in the welding apparatus of Example 4 described above. FIG. 4A shows the time change of the welding current Iw, FIG. 3B shows the time change of the welding voltage Vw, and FIG. 4C shows the time change of the peak period signal Tp. (D) shows the time change of the electrode minus period signal Ten, (E) shows the time change of the electrode plus irradiation start signal Tpa, and (F) shows the electrode minus irradiation. FIG. 4G shows the time change of the irradiation time signal Ta, and FIG. 4H shows the time change of the output setting signal Ps of the output synchronous laser oscillation device 62. FIG. Show. Since FIGS. 11A to 11H are the same as FIG. 15 described above, description thereof will be omitted. Hereinafter, FIG. 5H will be described.
[0065]
As shown in FIG. 6H, the output setting signal Ps is the value of the high output setting signal HPs when the irradiation time signal Ta shown in FIG. This is the value of the signal LPs. Therefore, the laser is irradiated at a high output during the irradiation time Ta before and after the polarity switching of the AC arc, and the laser is irradiated at a low output during the other periods.
[0066]
In the welding method of Example 4 described above, the arc can be re-ignited smoothly by irradiating the laser with high power during the irradiation time before and after the polarity switching, and the arc after the re-ignition is performed. No cutting occurs.
[0067]
In the output synchronous AC arc welding power supply device 74 of the third and fourth embodiments described above with reference to FIG. 13, the case where there is no low re-ignition voltage application circuit LVR is illustrated, but there is this low re-ignition voltage application circuit LVR. The same applies to the case.
[0068]
[effect]
FIG. 18 is a gap tolerance comparison diagram showing the effect of the present invention. This figure shows the maximum gap length [mm] shown on the vertical axis for the welding speed [m / min] shown on the horizontal axis under the welding conditions shown below. It is the figure compared by 2 and each welding method of this invention. The figure uses an aluminum / magnesium alloy (JIS A5052) with a thickness of 1 [mm] for the work piece and an aluminum / magnesium alloy wire (JIS A5356) with a diameter of 1.2 [mm] for the welding wire. This is a case where overlapped fillet welding is performed.
[0069]
As shown in the figure, in the laser irradiation DC arc welding method of the prior art 1, the maximum gap length that can be welded at a welding speed of 2 [m / min] is only 0.3 [mm], and the welding speed is If it exceeds 3 [m / min], only a smaller gap length is allowed. Further, in the AC arc welding method of the prior art 2, when the welding speed is 2 [m / min] or less, the maximum gap length that can be welded is as large as about 1.5 [mm]. Cannot weld due to lack.
In contrast, in the laser irradiation AC arc welding method of the present invention, the maximum gap length that can be welded at a welding speed of 2 [m / min] is as large as 1.5 [mm], and the welding speed is 5 [ m / min], the maximum gap length that can be welded is as large as 1.0 [mm]. For this reason, the welding method of the present invention has a large gap allowable range even during high-speed welding exceeding 2 [m / min], so that the application range in the actual construction can be greatly expanded.
[0070]
【The invention's effect】
In the laser irradiation AC arc welding method of the present invention, high-speed welding exceeding 2 [m / min] is possible by heat input of high-density energy by laser irradiation to the generating part of the AC arc, and around the irradiation part by laser irradiation. When the polarity of the AC arc is switched, the re-ignition of the arc is smoothed by the temperature rise of the arc, and no arc break occurs after re-ignition, and high-speed welding is achieved by filling the gap portion of the welding wire by AC arc welding. Since the gap tolerance range at the time becomes large, it is possible to perform good high-speed welding exceeding 2 [m / min] to about 5 [m / min] even for a workpiece having a large gap in the joint portion. .
In addition to the above effects, the inventions of the third and fourth embodiments precisely control the amount of heat input to the workpiece by laser irradiation by irradiating laser irradiation intermittently or switching between high and low outputs. Therefore, it is possible to improve the quality of the welding result and expand the application range.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a welding apparatus illustrating an embodiment of the present invention.
FIG. 2 is a configuration diagram of a welding apparatus of a laser irradiation DC arc welding method according to prior art 1;
FIG. 3 is a block diagram of a laser oscillation device of prior art 1;
FIG. 4 is a configuration diagram of a welding apparatus of the AC arc welding method of Prior Art 2.
FIG. 5 is a current / voltage waveform diagram showing an output waveform of prior art 2;
6 is a block diagram of an AC arc welding power supply device 72 of prior art 2. FIG.
FIG. 7 is a timing chart of each signal in Prior Art 2.
FIG. 8 is a configuration diagram of a welding apparatus according to the first embodiment.
FIG. 9 is a block diagram of an AC arc welding power supply device 73 with no re-ignition voltage applied according to the first embodiment.
FIG. 10 is a diagram showing the relationship between the welding current / voltage waveform and the AC arc generation state in Example 1;
11 is a block diagram of a low re-ignition voltage application AC arc welding power source apparatus according to Embodiment 2. FIG.
FIG. 12 is a configuration diagram of a welding apparatus of the output synchronous laser irradiation AC arc welding method according to the third embodiment.
FIG. 13 is a block diagram of an output synchronous AC arc welding power source 74 according to a third embodiment.
FIG. 14 is a block diagram of an output-synchronized laser oscillation device 61 according to a third embodiment.
FIG. 15 is a timing chart of signals in Example 3.
FIG. 16 is a block diagram of a high / low output synchronous laser oscillation device 62 according to a fourth embodiment;
FIG. 17 is a timing chart of signals in Example 4.
FIG. 18 is a gap tolerance comparison diagram showing the effect of the present invention.
[Explanation of symbols]
1 Welding wire
2 Workpiece
31 DC arc
33 AC Arc
41 Torch for laser
42 Welding torch
5 Feeding roll
6 Laser oscillator
61 Output synchronous laser oscillator
62 High and low output synchronous laser oscillator
71 DC arc welding power supply
72 AC Arc Welding Power Supply
73 AC Arc Welding Power Supply without Re-ignition Voltage
74 Output Synchronous AC Arc Welding Power Supply
AC commercial welding power supply
CM comparison circuit
Cm comparison signal
D2a to D2d secondary clarifier
DR polarity switching drive circuit
EA error amplification circuit
Ea Error amplification signal
EN Electrode negative polarity
EP electrode positive polarity
HPS high output setting circuit
HPs High output setting signal
IB Base current setting circuit
Ib Base current (setting signal)
ID current detection circuit
Id Current detection signal
IEN electrode negative current setting circuit
Ien electrode negative current (setting signal)
INT high frequency transformer
INV output control circuit
IP peak current setting circuit
Ip peak current (setting signal)
Isc Current control setting signal
Iw welding current
LPS low output setting circuit
LPs Low output setting signal
LVR low re-ignition voltage application circuit
LVrs Low re-ignition voltage
Nd electrode minus polarity drive signal
NTR electrode negative polarity transistor
Pd electrode positive polarity drive signal
PS output setting circuit
Ps output setting signal
PTR electrode plus polarity transistor
ROC laser output control circuit
SE electrode minus period switching circuit
Se switching setting signal
SP peak period switching circuit
SPS output setting switching circuit
ST output start circuit
St output start signal
STA output synchronization start circuit
t time
TA irradiation time timer circuit
Ta irradiation time (signal)
Tb Base period (signal)
TEA electrode minus irradiation start timer circuit
Tea electrode minus irradiation start (time / signal)
TEN electrode minus period timer circuit
Ten electrode minus period (signal)
TP peak period timer circuit
Tp Peak period (signal)
TPA electrode plus irradiation start timer circuit
Tpa electrode plus irradiation start (time / signal)
Vb Base voltage
VD voltage detection circuit
Vd Voltage detection signal
Vep electrode negative voltage
Vp peak voltage
VRS re-ignition voltage application circuit
Vrs Re-ignition voltage
VS voltage setting circuit
Vs Voltage setting signal
Vw welding voltage
WL Welding reactor

Claims (1)

In the AC arc welding method in which the consumable electrode is fed to the work piece, and an AC arc that alternately repeats the positive electrode polarity and the negative electrode polarity is generated between the consumable electrode and the work piece.
A laser with a predetermined high output during a predetermined irradiation time from immediately before switching the polarity of the AC arc to the arc generating part of the workpiece or its peripheral part, and with a predetermined low output during other periods. To increase the temperature of the workpiece and the tip of the welding wire adjacent to the workpiece and smoothly re-ignite the arc when switching the polarity of the AC arc without applying a re-ignition voltage. Laser irradiation AC arc welding method to be performed.

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