JP2014069225A - Arc welding control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that a lift movement of a torch is performed while continuing forward delivery of the wire, when it is determined that a tip of the wire comes into contact with a base metal, and "moment stop" can be effectively reduced by shortening a cycle time in the starting of the arc and also stabilizing the arc and reducing an arc start failure, in the control of separating wire from a base metal and generating an initial arc, however gas cavities remain when welding a galvanized steel sheet.SOLUTION: A welding control method includes an arc generation step of separating wire from a base metal and generating arc after bringing the wire into contact with the base metal, and a current application step of applying a current less than a critical current for a predetermined time in which a droplet formed in the wire does not leave. In the welding of the galvanized steel sheet, the surface of the steel sheet is broiled by using the heat of the droplet to vaporize the zinc, so that the welding is performed while the zinc on the surface of the steel sheet is reduced, and thereby the occurrence of gas cavities in the starting of the arc can be suppressed.

Description

  The present invention relates to an arc welding control method that realizes reduction of spatter, blowhole, and pit at the time of arc start when welding a surface-treated member such as a galvanized steel sheet.

  Galvanized steel sheets are excellent in rust prevention and corrosion resistance. Therefore, in recent years, it is used for automobile parts, building steel members, and the like, and its demand is increasing year by year.

  However, there are problems with the use of galvanized steel sheets. Zinc plated on the surface of a galvanized steel sheet has a lower melting point than iron. Therefore, when a galvanized steel sheet is welded, the zinc is vaporized, and zinc vapor passes through the molten pool and the molten metal and tends to diffuse outside. When the solidification of the molten metal is fast, zinc vapor cannot be diffused to the outside and remains as blowholes or pits (hereinafter referred to as pores) in the weld metal or on the weld metal surface. These can also lead to serious weld defects. In particular, at the time of arc start, there is a problem that the generation probability of pores is higher than that in steady welding. At the time of the arc start, compared to the steady welding performed after the arc start, it is difficult for heat to enter the galvanized steel sheet, and the zinc on the surface of the galvanized steel sheet cannot be volatilized.

  As a conventional arc start control, when it is determined that the tip of the welding wire is in contact with the base material that is the workpiece, the welding torch is operated by the manipulator that constitutes the industrial robot while continuing the forward feeding of the welding wire. Is known to generate an initial arc by pulling up the welding wire and pulling the welding wire away from the base material (see, for example, Patent Document 1).

  FIG. 5 is a diagram showing a schematic configuration of a welding system that performs the above-described conventional arc start control. The welding wire 31 that is a consumable electrode is fed out from the wire spool 32 toward the welding torch 34 by the wire feed motor 33. The welding power source device 35 generates an arc 38 by applying a predetermined welding current I and welding voltage V between the welding wire 31 and the base material 37 which is a workpiece to be welded via the welding torch 34 and the welding tip 36. At the same time, the wire feed motor 33 is controlled to perform welding. The robot manipulator 39 holds the welding torch 34, positions the welding torch 34 (not shown), and moves the welding torch 34 along a welding line (not shown). The robot manipulator 39 is controlled by the robot control device 40. Further, the robot control device 40 performs bidirectional communication S with the welding power source device 35 and transmits welding conditions such as a welding current I and a welding voltage V, a welding start command, a welding end command, and the like. To do.

  A consumable electrode type welding method performed by the welding system configured as described above will be described with reference to a time chart of FIG. FIG. 6 shows each situation of the moving speed TV of the welding torch 34, the feeding speed WF of the welding wire 31, the short-circuit determination signal A / S, the welding current I, and the welding voltage V in the vertical direction. FIG. 6 shows time on the horizontal axis. As a timing, a time point when the welding start signal is transmitted from the robot control device 40 to the welding power source device 35 is set as a time point T0. Thereafter, a time point T1 to a time point T5 are described later. Each timing is shown.

  In FIG. 6, when a welding start signal is transmitted from the robot controller 40 to the welding power source 35, the welding power source 35 applies a no-load voltage V 0 between the welding wire 31 and the base material 37, and The feeding motor 33 is activated to accelerate the welding wire 31 toward the base material 37. When the feeding speed of the welding wire 31 reaches the initial wire speed W0, the feeding of the welding wire 31 by the wire feeding motor 33 is stopped and the feeding of the welding wire 31 is continued at a constant speed. Eventually, when the welding wire 31 and the base material 37 come into contact with each other at time T1, a short circuit signal A / S indicating that a short circuit has occurred is output by a short circuit determination means (not shown) inside the welding power source device 35. . The short-circuit determination signal A / S is transmitted to the robot control device 40 by the bidirectional communication S, and the robot control device 40 controls the robot manipulator 39 to move the welding torch 34 in a direction that is generally away from the base material 37. The welding torch 34 is pulled up.

  Between the time point T1 and the time point T3 is an initial short-circuit period. During this period, the welding wire 31 is continuously fed at the initial wire speed W0, and the robot manipulator 39 continues the pulling-up operation of the welding torch 34. Therefore, the speed of the tip of the welding wire 31 is a combined speed of the wire speed WF and the torch speed TV, as indicated by the wavy line in the figure. Therefore, the tip of the welding wire 31 after the time point T1 presses the welding wire 31 against the base material 37 until the time point T2 when the combined speed indicated by the wavy line in the drawing becomes zero. However, after time T2, since the composite speed turns negative, the pressing amount decreases, and the short circuit is released at time T3. The time point T3 is a time point when the area of the triangle hji that is the lifting amount exceeds the area of the triangle fgh that is the pressing amount of the welding wire 31.

  When an initial short circuit occurs at time T1, welding power supply device 35 controls welding current I to current I1, increases the welding current to current I2 after a predetermined time has elapsed, and waits for the short circuit to open. The reason why the welding current is controlled to a relatively low current I1 as the first stage of the initial short circuit period is that the welding wire 31 is melted by Joule heating of the tip of the welding wire 31 due to the initial short circuit, and the arc 38 is generated. At the same time, the molten welding wire 31 is prevented from scattering and becoming spatter. The reason for changing the welding current from the current I1 to the current I2 is to give sufficient energy to generate the arc 38 when the short circuit is released at the time T3. Incidentally, the magnitude of the current I3 when the arc 38 is generated is a large current of 400 to 600A.

  As described above, when it is determined that the tip of the welding wire 31 is in contact with the base material 37 that is the workpiece, the robot manipulator 39 pulls up the welding torch 34 while continuing the forward feeding of the welding wire 31. As a result, the welding wire 31 is pulled away from the base material 37 to generate an initial arc. By doing so, it is not necessary to reverse the feeding wire 31 feeding operation or the robot manipulator 39 moving movement at the time of arc start, and the dead time is reduced and the tact time is shortened. It is possible to stabilize the arc 38 and effectively reduce “choco stop”.

JP 2009-12079 A

  The above-described conventional arc start control method can effectively reduce “choco stop” by shortening the tact time at the time of arc start, stabilizing the arc, and reducing arc start defects, and further reducing spatter. Can be reduced. However, when galvanized steel sheets are welded, zinc vapor tends to diffuse outside through the molten pool and molten metal, but the period until the molten pool is formed immediately after the arc start is higher than that of steady welding. Because of the rapid solidification of zinc, there was a problem that zinc vapor could not be diffused outside and remained as pores in the weld metal or on the weld metal surface.

  The present invention can be widely applied to the welding of surface-treated steel sheets such as galvanized steel sheets and the like, and an arc welding control method for surface-treated steel sheets such as galvanized steel sheets that realizes reduction of pores at the time of arc start The purpose is to provide.

  In order to solve the above problems, an arc welding control method of the present invention includes an arc generation step of generating an arc by separating a welding wire from a base material after contacting the welding wire and the base material; A first current energizing step for energizing a first current during a first predetermined period after the occurrence, and a second predetermined period longer than the first predetermined period after the first predetermined period There is provided a second current application step for supplying a second current larger than the first current in between.

  In the arc welding control method of the present invention, in addition to the above, the magnitude of the second current is such that the droplet formed on the welding wire is larger than the first current and does not separate.

  In addition to the above, the arc welding control method of the present invention further includes a third current energizing step for energizing a third current until the arc is generated in the arc generating step, wherein the first current is the third current. The current is larger than the current.

  In addition to the above, the arc welding control method of the present invention continuously increases the welding current from the first current to the second current or increases the welding current stepwise. is there.

  Moreover, in addition to the above, the arc welding control method of the present invention performs an arc generation step, a first current energization step, and a second current energization step during the arc start period. Pulse welding is performed during the steady welding period, and the second current has a smaller magnitude than the peak current during the steady welding period, and the second predetermined period is longer than the peak current period during the steady welding period.

  In addition to the above, the arc welding control method according to the present invention further includes reducing the current to the same magnitude as the base current of the pulse welding performed in the steady welding period after the second predetermined period, and then performing the pulse in the steady welding period. Welding is started.

  In addition to the above, the arc welding control method of the present invention is not limited to the above, and during the arc start period, the welding torch for feeding the welding wire is not moved in the welding line direction, and the steady welding period in which pulse welding is performed. The weld torch is moved in the weld line direction after the droplets have been detached at least once.

  Moreover, in addition to the above, the arc welding control method of the present invention uses a steel plate subjected to surface treatment as a base material.

  In addition to the above, the arc welding control method of the present invention uses a galvanized steel plate as a base material.

  As described above, according to the present invention, in welding of a steel sheet subjected to surface treatment such as a galvanized steel sheet, an arc generated from the droplet is formed in a large size without detaching the droplet at the wire tip at the start of the arc. The surface of the steel sheet is scooped with heat, the surface treatment part of the steel sheet is volatilized, and welding can be performed with a small amount of the surface treatment part of the steel sheet, suppressing the occurrence of pores (blow holes and pits) at the time of arc start can do.

The figure which shows schematic structure of the welding system in Embodiment 1 of this invention. The figure which shows the welding current waveform and droplet transfer state in Embodiment 1 of this invention The figure which shows the welding current waveform and droplet transfer state in Embodiment 1 of this invention (A) The figure which shows the welding current waveform in Embodiment 1 of this invention (b) The figure which shows the welding current waveform in Embodiment 1 of this invention (c) The welding current waveform in Embodiment 1 of this invention is shown. Figure The figure which shows schematic structure of the conventional arc welding apparatus Timing chart at arc start in conventional arc welding equipment

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment 1)
FIG. 1 shows a schematic configuration of the welding system according to the first embodiment. In FIG. 1, a welding power source device 1 includes a primary side rectification unit 3, a switching unit 4, a main transformer 5, a secondary side rectification unit 6, a reactor 7, a welding current detection unit 8, and a welding voltage detection. Unit 9, short circuit / arc detection unit 10, output control unit 11, wire feed speed control unit 12, output terminal 13 a, output terminal 13 b, and timer unit 21.

  A robot manipulator 22 and a teaching pendant 24 for teaching the robot manipulator 22 are connected to the robot controller 23. A welding torch 17 is attached to the robot manipulator 22. In addition, the welding power supply device 1 is connected to the robot control device 23 through a signal line, and is configured to be able to perform bidirectional communication with the robot control device 23. With this configuration, the teaching pendant 24 can be used to set the welding conditions such as the welding current and the welding voltage and the welding start time.

  In the welding power supply device 1, the primary side rectification unit 3 rectifies and outputs the output of the input power supply device 2 that outputs AC power. The switching unit 4 controls the welding output by converting the DC output from the primary side rectification unit 3 into AC. The main transformer 5 converts the AC output of the switching unit 4. The output of the main transformer 5 is output as a welding output via the secondary side rectification unit 6 that rectifies the secondary side output of the main transformer 5 and the reactor 7. The welding current detection unit 8 detects a welding current. The welding voltage detector 9 detects the welding voltage. Based on the signal from the welding voltage detection unit 9, the short circuit / arc detection unit 10 determines whether the welding state is a short circuit state in which the welding wire 15 and the base material 14 are in contact with each other, or the short circuit is opened. Then, it is determined whether or not the arc state where the arc 16 is generated. The output control unit 11 controls the switching unit 4 to control the welding output. The wire feed speed control unit 12 controls the wire feed unit 19 to control the feed speed of the wire 15. The timer unit 21 counts a predetermined time from the start of the arc start. The start of the arc start is instructed to start welding by the teaching pendant 24, the wire 15 is fed toward the base material 14, and a voltage is applied between the wire 15 and the base material 14, The time when the current flows when the wire 15 and the base material 14 come into contact with each other and the current is detected.

  The welding power source device 1 includes two output terminals, an output terminal 13a and an output terminal 13b. One of the two output terminals 13 a is electrically connected to the chip 18 that holds the wire 15 in the torch 17, and power is supplied to the wire 15 through the chip 18. The other output terminal 13 b of the two output terminals is electrically connected to the base material 14, and power is supplied to the base material 14. An arc 16 is generated between the tip of the wire 15 and the base material 14. The wire feeding unit 19 feeds the wire 15 from the wire storage unit 20 that stores the wire 15 toward the chip 18.

  The arc start control method will be described with reference to FIG. 2 for the welding system configured as described above. FIG. 2 shows the time change of the welding current Aw during welding in the consumable electrode type arc welding in a waveform, and also shows the droplet transfer state at that time. The consumable electrode type arc welding described in the first embodiment is pulse welding as steady welding after an arc start period having an arc generation step, a first current energization step, and a second energization step. Is to do. Details of each step will be described later. The base material 14 is a steel plate that has been subjected to surface treatment, and a galvanized steel plate is used as an example.

  In FIG. 2, the period from time ta to time td is a third current energization step in which the third current I3 is energized before the arc 16 is generated. First, at the time point ta, the teaching pendant 24 outputs a welding start signal, and the feeding of the wire 15 is started. When the wire 15 and the base material 14 come into contact with each other, it is determined that a short circuit has occurred by the short circuit / arc detection unit 10 inside the welding power source apparatus 1. And since the initial short circuit occurred, the welding current Aw is controlled to the initial short circuit current I0. The time counting unit 21 counts a predetermined time from the time point ta as a time starting point, and continuously outputs the initial short-circuit current I0 during the period up to the time point tb when the predetermined time t0 has elapsed. Thereafter, current control is performed from time tb, and the welding current Aw is increased with a predetermined slope. This increase is performed until the time point tc when the welding current Aw becomes the third current I3. When the welding current Aw reaches the third current I3, the third current I3 is continuously output during the third predetermined time t3 from the time point tc to the time point td when the arc is generated. Note that the magnitude of the third current I3 is equal to or greater than the initial short-circuit current I0 and equal to or less than the first current I1 described later. The magnitude of the initial short circuit current I0 is a small current of about 10 to 30A. The reason for controlling with a current of about 10 to 30 A during the initial short circuit period until the arc 16 is generated is that the wire 15 is melted by Joule heating of the tip of the wire 15 due to the initial short circuit, and melted simultaneously with the generation of the arc 16 This is to prevent the wires 15 from being scattered and becoming spatter.

  The reason for changing from the initial short-circuit current I0 to the third current I3 before generating the arc 16 is that the torch 17 is lifted up at time td to release the contact (short-circuit) between the wire 15 and the base material 14. This is to prevent arc breakage when the arc 16 is generated (opened) and to provide sufficient energy to generate the arc 16 when the short circuit is opened. As a current energization step pattern before the generation of the arc 16, for example, as shown in FIG. 3, the initial short circuit current I0 and the third current I3 may be equal. Therefore, the current application step before the generation of the arc 16 is not necessarily two steps as shown in FIG. However, if the energy at the time of outputting the third current I3 is too small, there is a possibility that an arc break occurs immediately after the arc 16 is generated. On the other hand, if the energy is too large, a large amount of spatter is generated when the arc is generated. there is a possibility. Therefore, it is necessary to obtain an appropriate value by experiments or the like. For example, the third current I3 is in the range of 30 to 80 A, and the third predetermined time t3 is in the range of 10 to 30 msec.

  The period from the time point td to the time point tg is a period in which a first current step for energizing the first current I1 after the occurrence of the arc and a second current step for energizing the second current I2 are performed. First, at the time point td, the short circuit is opened and the arc 16 is generated, and the welding current Aw is controlled to the first current I1. The time counting unit 21 counts a predetermined time from the time td as a time starting point, and continuously outputs the first current I1 during the period up to the time te when the first predetermined time t1 has elapsed. Thereafter, current control is performed from time te to increase the welding current Aw with a predetermined slope. This increase is performed until the time point tf when the welding current Aw becomes the second current I2. When the welding current Aw reaches the second current I2, the time counting unit 21 counts a predetermined time from the time point tf as a time starting point, and during the period up to the time point tg when the second predetermined time t2 has elapsed, the second current I2 Is output continuously. The second predetermined time t2 is longer than the first predetermined time t1 and the peak current period t4 of pulse welding performed in the steady welding period after the arc start period. Note that the longer the second predetermined time t2, the higher the effect of scoring zinc on the steel sheet surface. Further, the second current I2 is larger than the first current I1, and is larger than the critical current (about 280A) at which the droplet formed on the wire 15 separates or the peak current I4 of pulse welding performed during the steady welding period. small. By setting the second current I2 to such a magnitude, the surface of the steel plate can be rolled and the droplets can be prevented from detaching.

  According to the droplet transfer state shown in FIG. 2, the droplet at the tip of the wire 15 does not detach from the arc start (from the time td) until the time tg when the energization of the second current I2 ends. The droplet can be enlarged gradually.

  As a result, the surface of the steel sheet can be rolled by the arc heat generated from the large droplets formed at the tip portion of the wire 15. In the case of a galvanized steel sheet, zinc on the surface can be volatilized, and generation of pores at the time of arc start can be suppressed. In addition, the larger the droplet formed on the wire 15 and the shorter the distance from the base material 14, the more zinc is volatilized and the more effective the pore suppression.

  Further, after the arc 16 is generated, a two-stage current application step for changing the first current I1 to the second current I2 is performed, so that the wire 15 is gradually heated without suddenly applying heat. It can be formed and prevents the droplets from detaching before the time tg. Note that if the droplets are detached before the time tg, the time for scoring the steel sheet surface is reduced, and the amount of zinc volatilization is reduced, so that the possibility of generation of pores is increased.

  In the first embodiment, the arc 16 is generated when a lift-up start is performed to pull up the entire torch 17 at time td. Here, as described in the background art, the lift-up start means that when it is determined that the tip of the wire 15 is in contact with the base material 14 that is an object to be welded, the robot 15 continues to feed forward the wire 15. By pulling up the torch 17 by the manipulator 22, the wire 15 is pulled away from the base material 14 to generate an initial arc. By performing this control at the time of arc start, arc start failure can be reduced and tact time can be shortened. Further, it is possible to prevent the wire 15 from being melted and sputtered in a short circuit state, and to reduce spatter when the arc 16 is generated.

  After time tg, the current is reduced from the second current I2 to the same magnitude as the base current I5 of pulse welding performed in the steady welding period, and then pulse welding in the steady welding period is started. The reason why the welding current is reduced from the second current I2 to the base current I5 is to reduce the amount of heat once, thereby preventing the droplets from separating before performing pulse welding in the steady welding period.

  In the pulse welding performed in the steady welding period, the welding current Aw is increased to the peak current I4, the peak current I4 is continuously output during the predetermined time t4, and then the welding current Aw is changed from the peak current I4 to the base current. Lower to I5. Then, this pulse welding is repeated. It should be noted that the droplet formed on the tip portion of the wire 15 is detached from the wire 15 only when the welding current Aw becomes the base current I5.

  In the arc welding control method of the first embodiment, during the arc start period, the torch 17 for feeding the wire 15 is not moved in the welding line direction, but at least during the steady welding period in which pulse welding is performed. After releasing the droplet once, the torch 17 is moved in the weld line direction. In this way, by moving the torch 17 after the droplets have been released, it is possible to reduce spatter and improve weldability compared to the case where the torch 17 is moved without releasing the droplets.

  Note that the increase from the first current I1 to the second current I2 in the arc start period is not limited to the pattern 1 in FIG. 4A similar to FIG. As shown in the pattern 2 in FIG. 4B, the time may be continuously increased from the time td, which is the start time of the first predetermined time t1, to the time tf at which the second current I2 is reached. Alternatively, as shown in pattern 3 of FIG. 4C, the time may be increased in a stepped manner from the time td, which is the start time of the first predetermined time t1, to the time tf at which the second current I2 is reached. As shown in FIG. 4 (b) and FIG. 4 (c), by increasing the welding current continuously or stepwise, from the time td to the time tf without detaching the droplet at the tip of the wire 15. The amount of heat applied to the wire 15 during the period can be increased. When the total amount of heat is the same as that of the pattern 1 in FIG. 4A, the second predetermined time t2 can be shortened, and the tact time can be shortened compared to the pattern 1 in FIG. Alternatively, since the amount of heat is simply increased as compared with the pattern 1 in FIG. 4A, the amount of zinc on the surface of the galvanized steel sheet is increased, and the generation of pores at the time of arc start can be further suppressed. However, if it is increased too rapidly, the droplet formed on the wire 15 may be detached before the time tg. Accordingly, it is necessary to increase the amount of droplets so that the droplets formed on the wire 15 do not separate.

  Note that the first current I1, the first predetermined time t1, the second current I2, and the second predetermined time t2 are predetermined values, and are values suitable for the welding target through experiments or the like. do it. These values are set using the teaching pendant 24, for example.

  While the droplet formed at the tip of the wire 15 is small, the surface tension of the droplet is low, so that it may be detached when a high current is applied. Therefore, the current I1 at the first predetermined time t1 is set to a value of 50 A to 120 A, for example, and the first predetermined time t1 is based on the fact that the droplet is about 2 to 3 times the wire diameter. For example, a value from 30 msec to 50 msec is set.

  During the second predetermined time t2, the second current is used in order to shorten the time required to form a large droplet at the tip of the wire 15 and to sprinkle the steel plate with arc heat to volatilize zinc. I2 is set higher than the first current. The second current I2 is set to a value of 120A to 180A, for example. The second predetermined time t2 is set to a value of, for example, 30 msec to 60 msec with reference to the fact that the droplet is about 4 to 5 times the wire diameter.

  Further, the predetermined inclination for increasing the welding current Aw from the time point te to the time point tf is a gentle inclination so that the droplets are not detached, and is set to about 50 A / msec to 200 A / msec. Thus, the droplets are prevented from separating before time tf by forming the droplets gradually without applying heat to the wire 15 abruptly. If the droplets break off before the time tf, the time for scraping the surface of the steel sheet decreases, the amount of zinc volatilization decreases, or the droplet adheres to the surface of the steel sheet and covers the surface of the steel sheet. Therefore, the possibility that pores are generated increases.

  The above-described current value and predetermined time value are values determined after confirming that the droplets actually formed on the wire 15 are not detached during the arc start period with a high-speed camera or the like. If these values are as large as possible, the droplets are detached from the wire 15 and the surface of the steel sheet cannot be swollen, so that the surface zinc cannot be sufficiently volatilized and the pores generated at the arc start are suppressed. The effect will fade.

  As described above, according to the arc welding control method of the first embodiment, after the arc is generated in the arc start period, the first current I1 and the second current that are less than the critical current at which the droplets formed on the wire 15 do not detach. Current I2 is energized for a first predetermined time t1 and a second predetermined time t2, respectively. As a result, it is possible to volatilize the zinc on the surface of the steel sheet by the arc heat generated from the droplets at the tip of the wire 15 and to perform welding with a small amount of zinc on the surface of the steel sheet. can do.

  Furthermore, by performing a lift-up start in which the entire torch 17 is pulled up to generate the arc 16, it is possible to prevent the wire 15 from melting and becoming spatter in a short-circuit state, and to reduce spatter when the arc 16 is generated.

  The arc welding control method according to the present invention includes an arc generation step for generating an arc by bringing a welding wire and a base material into contact with each other and then generating an arc after the arc is generated, and a melt formed at the tip of the welding wire. In the welding of the galvanized steel sheet, a first current energizing step and a second current energizing step for energizing the first current I1 and the second current I2 less than the critical current for which the droplet does not separate for a predetermined time. Zinc is stripped off by galvanized steel sheet surface by arc heat generated from the droplets formed at the tip, and welding can be performed with a small amount of zinc on the surface of the galvanized steel sheet. Therefore, it is industrially useful as an arc welding control method for welding a surface-treated member.

DESCRIPTION OF SYMBOLS 1 Welding power supply device 2 Input power supply device 3 Primary side rectification part 4 Switching part 5 Main transformer 6 Secondary side rectification part 7 Reactor 8 Welding current detection part 9 Welding voltage detection part 10 Short circuit / arc detection part 11 Output control part 12 Wire Feeding speed control unit 13a, 13b Output terminal 14 Base material 15 Wire 16 Arc 17 Torch 18 Tip 19 Wire feeding unit 20 Wire storage unit 21 Timekeeping unit 22 Robot manipulator 23 Robot control device 24 Teaching pendant

Claims (9)

An arc generation step of generating an arc by separating the welding wire from the base material after contacting the welding wire and the base material;
A first current application step of supplying a first current during a first predetermined period after the arc is generated;
A second current application step of supplying a second current larger than the first current for a second predetermined period longer than the first predetermined period after the first predetermined period; Arc welding control method. The arc welding control method according to claim 1, wherein the magnitude of the second current is such that the droplet formed on the welding wire is larger than the first current and does not separate. 3. The arc according to claim 1, further comprising a third current energizing step for energizing a third current before the arc is generated in the arc generating step, wherein the first current is greater than or equal to the third current. Welding control method. The arc welding control method according to any one of claims 1 to 3, wherein the welding current is continuously increased from the first current to the second current, or the welding current is increased stepwise. In the arc start period, an arc generation step, a first current energization step, and a second current energization step are performed, pulse welding is performed in a steady welding period after the arc start period, and a second current is 5. The arc welding control method according to claim 1, wherein the arc welding control method is smaller in magnitude than a peak current in a steady welding period, and the second predetermined period is longer than a peak current period in the steady welding period. The arc welding control method according to claim 5, wherein after the second predetermined period, the current is reduced to the same magnitude as the base current of the pulse welding performed in the steady welding period, and then the pulse welding in the steady welding period is started. During the arc start period, the welding torch for feeding the welding wire is not moved in the direction of the welding line, and the welding torch is removed from the welding torch after detaching the droplets at least once during the steady welding period in which pulse welding is performed. The arc welding control method according to claim 5 or 6, wherein the arc welding control method is moved in the welding line direction. The arc welding control method according to any one of claims 1 to 7, wherein the base material is a steel plate that has been subjected to a surface treatment. The arc welding control method according to claim 8, wherein the base material is a galvanized steel sheet.

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