Welding apparatus and welding method

Abstract

To provide a welding apparatus and a welding method which are capable of controlling sputter in switching from short-circuit transfer arc welding to pulsed arc welding in arc-welding of alternately repeating short-circuit transfer arc welding and pulsed arc welding.SOLUTION: A welding apparatus 100 comprises: a welding current control part 110 which controls a welding current supplied from a welding power source 130 to a welding wire W in a welding torch 140 corresponding to short-circuit transfer arc welding and pulsed arc welding; and a wire feeding control part 120 which controls feed of the welding wire W so as to forward-reverse feed the welding wire W from a wire feeding device 150 in the period of short-circuit transfer arc welding and forward feed the welding wire W from the wire feeding device 150 in the period of pulsed arc welding, where the welding current control part 110 makes at least one pulse of a welding current after switching from short-circuit transfer arc welding to pulsed arc welding larger than a pulse at a steady state in pulsed arc welding.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a welding apparatus and a welding method. [Background technology]

[0002] Conventionally, short-circuit transfer arc welding has been known, in which the tip of a welding wire is short-circuited with the base metal to transfer molten metal to the base metal. Furthermore, a robot welding system has been developed in which, during the arc period of short-circuit transfer arc welding, the welding wire is fed in the forward direction toward the base metal, and during the short-circuit period, the welding wire is fed in the reverse direction away from the base metal, thereby reducing spatter.

[0003] Pulsed arc welding is also known, in which the welding current is made to have a periodic pulse waveform, and one molten droplet is detached from the welding wire and transferred to the base metal per pulse.

[0004] Furthermore, a welding method in which welding is performed by alternately switching between short circuit transfer arc welding and pulse arc welding is also known, and Patent Document 1 discloses an arc welding method in which welding is performed by alternately switching between a period in which the welding wire is fed forward and backward and a period in which the welding wire is fed forward and pulse arc welding is performed. In Patent Document 1, in order to smoothly switch between short circuit transfer arc welding and pulse arc welding, the welding wire is fed backward when the period in which pulse arc welding is performed begins, and is switched to forward feeding after a predetermined period has elapsed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-23968 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the arc welding method disclosed in Patent Document 1, when switching to pulse arc welding (immediately after switching), the resistance heat generated by the current flowing through the welding wire and the heat input from the arc generated at the tip of the welding wire are insufficient. As a result, in pulse arc welding, one droplet cannot be detached from the welding wire per pulse (welding current in a pulse waveform), and this may become a large droplet, resulting in the risk of spatter scattering.

[0007] Therefore, an object of the present invention is to provide a welding device and a welding method that can suppress spatter when switching from short-circuit transfer arc welding to pulse arc welding in arc welding in which short-circuit transfer arc welding and pulse arc welding are alternately repeated. [Means for solving the problem]

[0008] A welding apparatus according to one embodiment of the present invention is a welding apparatus that alternately repeats short-circuit transfer arc welding and pulse arc welding, and includes a welding current control unit that controls the welding current supplied to the welding wire in the welding torch from the welding power source unit depending on whether short-circuit transfer arc welding or pulse arc welding is performed, and a wire feed control unit that controls the feeding of the welding wire so that the welding wire is fed in forward and reverse directions from the wire feeder during short-circuit transfer arc welding, and so that the welding wire is fed in forward directions from the wire feeder during pulse arc welding. The welding current control unit makes at least one pulse of the welding current after switching from short-circuit transfer arc welding to pulse arc welding larger than the steady-state pulse in pulse arc welding.

[0009] According to this aspect, the welding current control unit controls the welding current supplied from the welding power source unit to the welding wire in the welding torch in accordance with short-circuit transfer arc welding and pulse arc welding, and the wire feed control unit controls the feeding of the welding wire so that the welding wire is fed forward and backward from the wire feeder during short-circuit transfer arc welding and fed forward from the wire feeder during pulse arc welding. The welding current control unit then makes at least one pulse of the welding current after switching from short-circuit transfer arc welding to pulse arc welding larger than the pulse during steady state in pulse arc welding. This increases the resistance heat generated by the current flowing through the welding wire, eliminates the heat input deficiency, and appropriately separates one droplet from the welding wire for at least one pulse after switching to pulse arc welding. As a result, spattering during switching from short-circuit transfer arc welding to pulse arc welding can be suppressed.

[0010] In the above aspect, the welding current control unit may make the peak current of at least one pulse larger than the peak current of the pulse in a steady state.

[0011] According to this aspect, by increasing the peak current of at least one pulse after switching from short-circuit transfer arc welding to pulse arc welding, it is possible to appropriately increase the resistance heat generated by the current flowing through the welding wire and eliminate insufficient heat input.

[0012] In the above aspect, the welding current control section may set a base current of at least one pulse to be greater than a base current of the pulse in a steady state.

[0013] According to this aspect, by increasing the peak current of at least one pulse after switching from short-circuit transfer arc welding to pulse arc welding and increasing the base current accordingly, the relationship between the peak current and the base current can be maintained and stabilized in the same manner as for a steady-state pulse.

[0014] In the above aspect, the welding current control unit may set the peak time of at least one pulse to be longer than the peak time of a pulse in a steady state.

[0015] According to this aspect, by increasing the peak time for supplying the peak current of at least one pulse after switching from short circuit transfer arc welding to pulse arc welding, it is possible to appropriately increase the resistance heat generated by the current flowing through the welding wire and eliminate insufficient heat input.

[0016] In the above-described aspect, the welding current control unit may make the multiple pulses of the welding current after switching from short-circuit transfer arc welding to pulse arc welding larger than the pulses during steady state in pulse arc welding, and gradually reduce them to approach the pulses during steady state.

[0017] According to this aspect, by increasing the number of pulses after switching from short-circuit transfer arc welding to pulse arc welding, it is possible to appropriately increase the resistance heat generated by the current flowing through the welding wire during a specified period (corresponding to the number of pulses), thereby eliminating insufficient heat input.

[0018] A welding method according to one embodiment of the present invention is a welding method that alternates between short-circuit transfer arc welding and pulse arc welding, in which during short-circuit transfer arc welding, the welding wire is fed in both forward and reverse directions from the wire feeding device by the wire feeding control unit, and during pulse arc welding, the welding wire is fed in the forward direction from the wire feeding device by the wire feeding control unit, and at least one pulse of the welding current after switching from short-circuit transfer arc welding to pulse arc welding is made larger than the steady-state pulse in pulse arc welding by a welding current control unit that controls the welding current supplied from the welding power source to the welding wire in the welding torch depending on whether short-circuit transfer arc welding or pulse arc welding is performed.

[0019] According to this aspect, during the period of short-circuit transfer arc welding, the wire feeder feeds the welding wire in the forward and reverse directions by the wire feeder according to short-circuit transfer arc welding and pulse arc welding, and during the period of pulse arc welding, the wire feeder feeds the welding wire in the forward direction by the wire feeder. Then, the welding current control unit makes at least one pulse of the welding current after switching from short-circuit transfer arc welding to pulse arc welding larger than the pulse during steady state in pulse arc welding. This increases the resistance heat generated by the current flowing through the welding wire, eliminates the heat input deficiency, and appropriately separates one droplet from the welding wire for at least one pulse after switching to pulse arc welding. As a result, spattering during switching from short-circuit transfer arc welding to pulse arc welding can be suppressed. Effect of the Invention

[0020] According to the present invention, a welding device and a welding method can be provided that can suppress spatter when switching from short-circuit transfer arc welding to pulse arc welding in arc welding in which short-circuit transfer arc welding and pulse arc welding are alternately repeated. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram showing a welding device 100 according to an embodiment of the present invention. [Diagram 2] 1 is a diagram showing the state of feeding of a welding current and a welding wire W in a welding method in which short-circuit transfer arc welding and pulse arc welding are alternately repeated. FIG. [Diagram 3] FIG. 11 is a diagram showing an example of the feeding of the welding current and the welding wire W after switching from short-circuit transfer arc welding to pulse arc welding. [Figure 4] 11A to 11C are diagrams showing another example of the feeding of the welding current and the welding wire W after switching from short-circuit transfer arc welding to pulse arc welding. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings. Note that the embodiment described below is merely a specific example for carrying out the present invention, and is not intended to limit the interpretation of the present invention. In addition, in order to facilitate understanding of the description, the same reference numerals are used as far as possible for the same components in each drawing, and duplicated descriptions may be omitted.

[0023] <One embodiment> [Welding equipment configuration] Fig. 1 is a schematic diagram showing a welding device 100 according to one embodiment of the present invention. As shown in Fig. 1, the welding device 100 includes a welding current control unit 110, a wire feed control unit 120, a welding power source unit 130, a welding torch 140, and a wire feeder 150, and alternately repeats short-circuit transfer arc welding and pulse arc welding.

[0024] In addition, welding current control unit 110 and wire feed control unit 120 may be configured as a welding power supply device together with welding power supply unit 130, or may be configured as a control unit (control device) separate from welding power supply unit 130 (welding power supply device).

[0025] Welding current control unit 110 controls the welding current supplied from welding power supply unit 130 to welding wire W in welding torch 140 in accordance with short-circuit transfer arc welding and pulse arc welding.

[0026] Wire feed control unit 120 controls the feeding of welding wire W in wire feeder 150, and controls motor M so as to feed welding wire W forward and reverse during short circuit transfer arc welding and forward during pulse arc welding. Here, forward feeding means feeding the welding wire W fed from wire feeder 150 in a direction approaching a workpiece (base material) to be welded, and forward and reverse feeding means repeatedly feeding the welding wire W in a direction approaching base material T and reverse feeding in a direction away from base material T.

[0027] The welding power supply unit 130 supplies a welding current and a welding voltage to generate an arc between a tip of the welding wire W in the welding torch 140 and the base material T. The welding current supplied by the welding power supply unit 130 is controlled by the welding current control unit 110 in accordance with whether short-circuit transfer arc welding or pulse arc welding is performed.

[0028] The welding torch 140 includes a contact tip for applying a voltage to the welding wire W, and a welding voltage is applied between the contact tip and the base metal T, causing a welding current to flow.

[0029] The wire feeder 150 feeds the welding wire W to the welding torch 140. The wire feeder 150 is configured to include a motor M and a roller, and the feeding of the welding wire W is controlled by a wire feed control unit 120.

[0030] The welding apparatus 100 performs arc welding by alternating between short-circuit transfer arc welding and pulse arc welding. As described above, the welding current control unit 110 controls the welding current supplied from the welding power source unit 130 in accordance with short-circuit transfer arc welding and pulse arc welding, and the wire feed control unit 120 controls the feeding of the welding wire W in the wire feeder 150.

[0031] 2 is a diagram showing the state of feeding of the welding current and the welding wire W in a welding method in which short circuit transfer arc welding and pulse arc welding are alternately repeated. With reference to FIG. 2, the welding current controlled by the welding current control unit 110 and the feeding of the welding wire W controlled by the wire feed control unit 120 will be described.

[0032] Welding current control unit 110 controls the welding current supplied from welding power supply unit 130 in accordance with short-circuit transfer arc welding and pulse arc welding.

[0033] During the short circuit transfer arc welding period, the welding current control unit 110 increases the welding current so as to rise during the short circuit period in which the tip of the welding wire W and the base metal T are short circuited, and then controls the welding current to be supplied in a predetermined welding current (approximately pulsed) during the arc period in which an arc is generated between the tip of the welding wire W and the base metal T, and then reduces the welding current in preparation for the next short circuit period. During the short circuit transfer arc welding period, the welding current control unit 110 repeatedly performs these controls.

[0034] Wire feed control unit 120 controls welding wire W fed from wire feeder 150 to be fed in reverse (at a constant feed speed: negative) in a direction away from base material T during the short circuit period, and to be fed in forward (at a constant feed speed: positive) in a direction approaching base material T during the arc period. During the short circuit transfer arc welding period, wire feed control unit 120 repeats these operations, i.e., feeds welding wire W from wire feeder 150 in forward and reverse directions.

[0035] During the pulse arc welding period, the welding current control unit 110 controls the supply of the welding current as a pulse waveform with an appropriate period so that one droplet is detached from the welding wire W per one pulse.

[0036] Wire feed control unit 120 controls welding wire W fed from wire feeder 150 so as to be fed in a forward direction toward base material T (feed speed is constant: forward).

[0037] Here, the period of short circuit transfer arc welding and the period of pulse arc welding are set in advance, and accordingly, welding current control unit 110 and wire feed control unit 120 respectively control the welding current supplied from welding power source unit 130 and the feeding of welding wire W in wire feeder 150. Furthermore, welding current control unit 110 and wire feed control unit 120 may control the above-mentioned welding current and feeding of welding wire W according to preset welding conditions related to welding (e.g., specific settings of the magnitude of the welding current and / or welding voltage, and the feeding speed of the welding wire, etc.).

[0038] Each of these items may be set automatically or manually, and may also be set and adjusted by the user.

[0039] Furthermore, when a welding robot is used as welding device 100, for example, a user operates a teaching pendant to teach the welding robot how to operate, and the taught operation is stored as an operation program in a storage unit such as a memory in the robot control device. When the welding robot operates according to the operation program, welding current control unit 110 and wire feed control unit 120 may control the welding current supplied from welding power source unit 130 and the feed of welding wire W in wire feeder 150, respectively, based on the period of short circuit transfer arc welding, the period of pulse arc welding, the welding current, and the feed speed of welding wire W, which are taught in the operation program.

[0040] [Welding current and wire feed when switching to pulsed arc welding] Next, the welding current and wire feeding when switching from short-circuit transfer arc welding to pulse arc welding will be described in detail.

[0041] Fig. 3 is a diagram showing an example of the feeding of the welding current and the welding wire W after switching from short circuit transfer arc welding to pulse arc welding. As shown in Fig. 3, during the period of short circuit transfer arc welding, the wire is fed forward and reversely by the wire feed control unit 120, and immediately after switching to pulse arc welding, the reverse feeding speed of the wire may be reduced and forward feeding may be performed after a predetermined period has elapsed. Then, the welding current control unit 110 controls the welding current to be supplied as a pulse waveform.

[0042] Immediately after switching to pulse arc welding, the feed speed (negative) is reduced and wire is fed in reverse for a predetermined period to increase the arc length, and then the welding current control unit 110 controls to supply a welding current as the first pulse waveform in pulse arc welding. This makes it possible to more appropriately form droplets when switching to pulse arc welding, and to smoothly switch from short circuit transfer arc welding to pulse arc welding.

[0043] Welding current control unit 110 makes the first pulse larger than the subsequent pulses in the steady state. For example, welding current control unit 110 makes the peak current of the first pulse larger than the peak current of the pulse in the steady state. Specifically, the peak current of the first pulse is made about 10% larger than the peak current of the pulse in the steady state. For example, if the peak current of the pulse in the steady state is 350A, the peak current of the first pulse may be 385A.

[0044] Immediately after switching from short-circuit transfer arc welding, which has a low heat input, to pulse arc welding, the peak current of the first pulse is increased to increase the resistance heat generated by the current flowing through the welding wire W, eliminating the insufficient heat input and appropriately causing one droplet to detach from the welding wire W in response to the first pulse. As a result, spattering can be suppressed when switching from short-circuit transfer arc welding to pulse arc welding.

[0045] Here, the peak current of the first pulse, which is made larger than the steady-state pulse, is made larger, but the base current may also be made larger accordingly, and it is preferable to maintain and stabilize the relationship between the peak current and the base current between the steady-state pulse and the first pulse, which is made larger than the steady-state pulse.

[0046] Also, here, as a specific example of making the first pulse larger than the steady pulse, the peak current of the first pulse is made larger, but this is not limited thereto, and for example, the peak time during which the peak current of the first pulse is supplied may be made larger than the peak time during which the peak current of the steady pulse is supplied. This similarly increases the resistance heat generated by the current flowing through the welding wire W immediately after switching from short circuit transfer arc welding to pulse arc welding, eliminates the heat input deficiency, and allows one droplet to be appropriately detached from the welding wire W in response to the first pulse.

[0047] As described above, according to the welding device 100 according to one embodiment of the present invention, in arc welding in which short-circuit transfer arc welding and pulse arc welding are alternately repeated, the welding current control unit 110 controls the welding current supplied from the welding power source unit 130 to the welding wire W in the welding torch 140 according to short-circuit transfer arc welding and pulse arc welding, and the wire feed control unit 120 controls the feeding of the welding wire W so that the welding wire W is fed forward and backward from the wire feeder 150 during the short-circuit transfer arc welding period, and the welding wire W is fed forward from the wire feeder 150 during the pulse arc welding period. Then, the welding current control unit 110 increases the resistance heat generated by the current flowing through the welding wire W by making the first pulse larger than the subsequent steady pulse immediately after switching from short-circuit transfer arc welding to pulse arc welding, thereby eliminating the heat input shortage and appropriately detaching one droplet from the welding wire W in response to the first pulse. As a result, spattering can be suppressed when switching from short-circuit transfer arc welding to pulse arc welding.

[0048] In this embodiment, the first pulse after switching from short-circuit transfer arc welding to pulse arc welding is made larger than the pulse during steady state, but the number of pulses that is made larger is not limited to one. For example, multiple pulses after switching from short-circuit transfer arc welding to pulse arc welding may be made larger than the pulse during steady state.

[0049] Immediately after switching from short-circuit transfer arc welding, which has a low heat input, to pulse arc welding, the number of pulses is increased, thereby increasing the resistance heat generated by the current flowing through the welding wire W during a specified period (the number of pulses), eliminating the heat input deficiency, and allowing one droplet to appropriately detach from the welding wire W for each of the number of pulses.

[0050] Fig. 4 is a diagram showing another example of the welding current and the feeding of the welding wire W after switching from short-circuit transfer arc welding to pulse arc welding. As shown in Fig. 4, the peak current of three pulses after switching from short-circuit transfer arc welding to pulse arc welding is increased to be larger than the pulses in a steady state. Furthermore, the peak current of each of the three pulses is reduced in stages to gradually approach the pulses in a steady state.

[0051] 3 and 4, the wire feed control unit 120 feeds the welding wire W at a constant speed during the pulse arc welding period, but the speed may be changed according to the magnitude of the welding current (pulse). Specifically, when the pulse is increased, the feed speed of the welding wire W may be increased according to the magnitude of the pulse.

[0052] The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The elements of the embodiments, as well as their arrangements, materials, conditions, shapes, sizes, etc., are not limited to those shown as examples and can be changed as appropriate. In addition, configurations shown in different embodiments can be partially substituted or combined with each other. [Explanation of symbols]

[0053] 100...welding device, 110...welding current control unit, 120...wire feed control unit, 130...welding power source unit, 140...welding torch, 150...wire feeder, M...motor, T...base material, W...welding wire

Claims

1. A welding device that alternately repeats short-circuit transfer arc welding and pulse arc welding, a welding current control unit that controls a welding current supplied from a welding power source unit to a welding wire in a welding torch in accordance with the short circuit transfer arc welding and the pulse arc welding; a wire feed control unit that controls feeding of the welding wire so that the welding wire is fed in forward and reverse directions from the wire feeder during the short circuit transfer arc welding period and is fed in the forward direction from the wire feeder during the pulse arc welding period, The welding current control unit makes at least one pulse of the welding current after switching from the short circuit transfer arc welding to the pulse arc welding larger than a pulse during steady state in the pulse arc welding. Welding equipment.

2. The welding current control unit sets a peak current of the at least one pulse to be greater than a peak current of the pulse in a steady state.

2. The welding apparatus of claim 1.

3. The welding current control unit sets a base current of the at least one pulse to be larger than a base current of the pulse in a steady state.

3. The welding apparatus of claim 2.

4. The welding current control unit sets a peak time of the at least one pulse to be longer than a peak time of the pulse in a steady state.

2. The welding apparatus of claim 1.

5. The welding current control unit makes the multiple pulses of the welding current after switching from the short circuit transfer arc welding to the pulse arc welding larger than the pulses during steady state in the pulse arc welding, and gradually reduces the pulses to approach the pulses during steady state.

2. The welding apparatus of claim 1.

6. A welding method in which short-circuit transfer arc welding and pulse arc welding are alternately repeated, During the short circuit transfer arc welding period, the welding wire is fed in forward and reverse directions from the wire feeder by the wire feed control unit, During the pulse arc welding period, the welding wire is forward-fed from the wire feeder by the wire feed control unit, A welding current control unit controls a welding current supplied from a welding power source to the welding wire in the welding torch in accordance with the short-circuit transfer arc welding and the pulse arc welding, so that at least one pulse of the welding current after switching from the short-circuit transfer arc welding to the pulse arc welding is made larger than a steady pulse in the pulse arc welding. Welding method.

Images