Welding control method, welding control device, welding power source, welding system, program, welding method, and additive manufacturing method

Abstract

In an arc welding method in which the forward feeding and the reverse feeding of the front end of the wire are periodically repeated, both the stable depth of penetration and the reduction of spatter are taken into consideration. The control is performed as follows: the period in which the forward feeding period (T P ) and the reverse feeding period (T N ) are combined is set as one cycle, the frequency (f) is set to 50 to 150 Hz, the relationship between the average current (I IP ) of the current non-suppression period (T P‑AVE ) and the average current (I IB ) of the current suppression period (T B‑AVE ) is set to 0.65 ≤ I P‑AVE / (I P‑AVE + I B‑AVE ) ≤ 0.90, the variation amplitude of the position of the front end of the wire between the uppermost end and the lowermost end, that is, the wave height (Wh) is set to 14 to 35% with respect to the distance between the nozzle and the base material, the relationship between an arbitrary current non-suppression period (T IP ) and the current suppression period (T IB ) immediately after it is set to 0.30 ≤ T IB / (T IP + T IB ) ≤ 0.60, the relationship between the forward feeding period (T P ) and the reverse feeding period (T N ) is set to 0.40 ≤ T N / (T P + T N ) ≤ 0.70, and the relationship between the current non-suppression period (T IP ), the current suppression period (T IB ), the forward feeding period (T P ), and the reverse feeding period (T N ) is set to {T N / (T P + T N )} > {T IB / (T IP + T IB )}, and the current non-suppression period T IP occupies a period of more than 2 / 3 of the forward feeding period (T P ).

Description

Technical Field

[0001] This invention relates to welding control methods, welding control devices, welding power sources, welding systems, programs, welding methods, and additional manufacturing methods in arc welding where the welding wire feed alternately and periodically repeats forward and reverse feed. Background Technology

[0002] In the welding of thick plates, particularly in industries such as steel frames and construction machinery, ensuring a certain depth of penetration is crucial. Furthermore, in the welding of galvanized steel sheets used in industries like automobiles, preventing porosity defects is essential. Ensuring this depth of penetration and preventing porosity defects can be achieved by increasing the thermal energy of the electric arc. Therefore, gas-shielded metal arc welding (GMAW) has been employed, utilizing shielding gases with high potential gradients, such as carbon dioxide, to increase the arc current density or the welding current itself. However, the use of shielding gases with high potential gradients and high welding currents has become a major cause of increased sputtering, leading to a decrease in weld operability, primarily due to sputtering.

[0003] To address the aforementioned problems, Patent Document 1 discloses the following: In the case of arc welding by alternately and periodically repeating forward and reverse feeds of the welding wire (hereinafter also referred to as "wire") which serves as a consumable electrode, the goal is to suppress sputtering even when a large current flows through the wire. When the wire tip is fed into the base material during the periodic switching between forward and reverse feeds, a control unit that changes the welding current according to the periodically varying position of the wire tip enables sputtering reduction even in a high-current domain capable of efficient welding with high heat input, i.e., a current domain with a transition mode other than short-circuit transfer.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-49506 Summary of the Invention

[0007] -The problem the invention aims to solve-

[0008] As mentioned above, Patent Document 1 discloses a method for reducing sputtering in a high-current domain where welding can be performed efficiently with high heat input, but it does not specifically mention the penetration depth. That is, Patent Document 1 does not mention any effect that can ensure a stable penetration depth or prevent porosity defects.

[0009] Patent Document 1 describes an arc welding method involving periodic forward and reverse feeds. Unlike conventional short-circuit transfer methods, this method involves control to prevent short circuits. However, due to variations in workpiece conditions, welding posture, and other welding-related factors, short circuits and misaligned droplet detachment timing can occur during welding control, potentially leading to unstable weld penetration and increased spatter generation. Therefore, regardless of the welding environment, a higher precision welding control system that balances stable weld penetration and spatter reduction is required.

[0010] The present invention was made in view of the above-mentioned problems, and its object is to provide a welding control method, welding control device, welding power source, welding system, program, welding method and additional manufacturing method, which can achieve both stable penetration depth and reduced sputtering in an arc welding mode in which the feed of the welding wire alternately and periodically repeats forward and reverse feed.

[0011] -Methods for solving problems-

[0012] Therefore, the above-mentioned objective of the present invention is achieved by the structure of the welding control method described below [1].

[0013] [1] A welding control method, in gas metal arc welding of a welding wire to which a welding current is supplied, wherein the feed rate of the welding wire is controlled such that the tip of the welding wire moves from the position furthest from the base material (i.e., the uppermost end) to the position closest to the base material (i.e., the lowermost end), i.e., the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N While periodically switching the welding current, the welding current is fed into the base material, and at least based on the tip position of the welding wire or the feed speed signal of the welding wire, the welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB The welding control is performed as follows: the forward feed period T is controlled... P and the reverse feed period T N The combined period is defined as a cycle, and its frequency f is set to 50–150 Hz. The non-suppressed current period T is defined as... IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE)≤0.90, the variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, relative to the distance between the tip and the base material of the welding wire, is set to 14-35%, and the arbitrary current non-suppression period T is set to IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB If )≤0.60, the forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and during the non-suppression period of the current T IP During the current suppression period T IB The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +T IB Furthermore, during the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

[0014] Furthermore, the above-mentioned objective of the present invention is achieved by the structure of the welding control device described below [2].

[0015] [2] A welding control device, in gas metal arc welding of a welding wire, controls the feed speed of the welding wire such that the tip of the welding wire moves from the position furthest from the base material (i.e., the uppermost end) to the position closest to the base material (i.e., the lowermost end), i.e., the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N While periodically switching the welding current, the welding current is fed into the base material, and at least based on the tip position of the welding wire or the feed speed signal of the welding wire, the welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB The welding control device has the function of controlling the forward feed period T as follows: P and the reverse feed period T NThe combined period is defined as a cycle, and its frequency f is set to 50–150 Hz. The non-suppressed current period T is defined as... IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE )≤0.90, the variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, relative to the distance between the tip and the base material of the welding wire, is set to 14-35%, and the arbitrary current non-suppression period T is set to IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB If )≤0.60, the forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and during the non-suppression period of the current T IP During the current suppression period T IB The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +T IB Furthermore, during the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

[0016] Furthermore, the above-mentioned objective of the present invention is achieved by the following [3] structure related to the welding power source.

[0017] [3] A welding power source equipped with the welding control device described in [2].

[0018] Furthermore, the above-mentioned objective of the present invention is achieved by the structure of the welding system described below [4].

[0019] [4] A welding system comprising the welding control device described in [2] or the welding power source described in [3].

[0020] Furthermore, the above-mentioned objective of the present invention is achieved by the structure of the procedure described below [5].

[0021] [5] A program that enables a computer of a welding system having at least a welding control device to perform functions in gas metal arc welding of a welding wire, wherein the welding control device controls the feed rate of the welding wire such that the tip of the welding wire moves from the position furthest from the base material (i.e., the uppermost end) to the position closest to the base material (i.e., the lowermost end), i.e., the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N While periodically switching the welding current, the welding current is fed into the base material, and at least based on the tip position of the welding wire or the feed speed signal of the welding wire, the welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB In this function, the welding control device is controlled as follows: the forward feed period T is controlled... P and the reverse feed period T N The combined period is defined as a cycle, and its frequency f is set to 50–150 Hz. The non-suppressed current period T is defined as... IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE )≤0.90, the variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, relative to the distance between the tip and the base material of the welding wire, is set to 14-35%, and the arbitrary current non-suppression period T is set to IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB If )≤0.60, the forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and during the non-suppression period of the current T IP During the current suppression period T IB、 The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (TP +T N )}>{T IB / (T IP +T IB Furthermore, during the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

[0022] Furthermore, the above-mentioned objective of the present invention is achieved by the structure described below [6] of the welding method.

[0023] [6] A welding method in which welding control is performed while the gas metal arc welding is performed, wherein in the gas metal arc welding in which welding current is supplied to the welding wire, the welding control controls the feed rate of the welding wire so that the tip of the welding wire moves from the position furthest from the base material (i.e., the uppermost end) to the position closest to the base material (i.e., the lowermost end), i.e., the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N While periodically switching the welding current, the welding current is fed into the base material, and at least based on the tip position of the welding wire or the feed speed signal of the welding wire, the welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB The welding control is performed as follows: the forward feed period T is controlled to be such that... P and the reverse feed period T N The combined period is defined as a cycle, and its frequency f is set to 50–150 Hz. The non-suppressed current period T is defined as... IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE )≤0.90, the variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, relative to the distance between the tip and the base material of the welding wire, is set to 14-35%, and the arbitrary current non-suppression period T is set to IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB If )≤0.60, the forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (TP +T N )≤0.70, and during the non-suppression period of the current T IP During the current suppression period T IB The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +T IB Furthermore, during the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

[0024] Furthermore, the above-mentioned objective of the present invention is achieved by the following [7] structure involved in the additional manufacturing method.

[0025] [7] An additional manufacturing method, wherein welding control is performed simultaneously with said additional manufacturing, wherein in said additional manufacturing using gas metal arc welding in which welding current is supplied to the welding wire, the welding control controls the feed rate of the welding wire such that the tip of the welding wire moves from the position furthest from the base material (i.e., the uppermost end) to the position closest to the base material (i.e., the lowermost end), i.e., the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N While periodically cutting, the welding current is fed into the base material, and at least based on the tip position of the welding wire or the feed speed signal of the welding wire, the welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB The welding control is performed as follows: the forward feed period T is controlled to be such that... P and the reverse feed period T N The combined period is defined as a cycle, and its frequency f is set to 50–150 Hz. The non-suppressed current period T is defined as... IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE )≤0.90, the variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, relative to the distance between the tip and the base material of the welding wire, is set to 14-35%, and the arbitrary current non-suppression period T is set to IPWith the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB If )≤0.60, the forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and during the non-suppression period of the current T IP During the current suppression period T IB The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +T IB Furthermore, during the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

[0026] -Invention Effects-

[0027] According to the welding control method, welding control device, welding power source, welding system, program, welding method, and additional manufacturing method of the present invention, in an arc welding mode in which the feed of the welding wire alternately and periodically repeats forward and reverse feed, it is possible to achieve both stable penetration depth and reduced sputtering. Attached Figure Description

[0028] Figure 1 This is a schematic diagram showing a structural example of the welding system involved in this embodiment.

[0029] Figure 2 This is a block diagram showing the outline structure of the power control unit in a welding power source.

[0030] Figure 3 This indicates the wire feed speed F W Waveform diagram showing the time variation.

[0031] Figure 4 It is a waveform diagram illustrating the time-varying position of the welding wire tip.

[0032] Figure 5 This is a flowchart illustrating an example of basic control of welding current in this embodiment.

[0033] Figure 6This is a diagram illustrating a control example of a current setting signal Ir that represents a specified welding current value.

[0034] Figure 7 These are continuous photographs taken by a high-speed camera, representing an example of the progress of welding in a conventional short-circuit transition method. They are also substitute photographs taken at each elapsed time for Test No. 24, the reference example described later.

[0035] Figure 8 These are continuous photographs taken by a high-speed camera, representing an example of the progress of welding in this embodiment. They are also substitute photographs taken at each elapsed time for Test No. 8 of the embodiment described later.

[0036] Figure 9A This is used to explain the welding current setting value I. P1 The end position and welding current setting I P2 The setting of the end position indicates the wire feed speed F W A diagram showing the relationship between the wire tip position and the welding current setting.

[0037] Figure 9B It is used to explain the current suppression period T IB The setting of the end position indicates the wire feed speed F W A diagram showing the relationship between the wire tip position and the welding current setting.

[0038] Figure 10 It is a graph used to represent the relationship between the number of short circuits and the penetration depth. Detailed Implementation

[0039] Hereinafter, embodiments of the welding control method, welding control device, welding power source, welding system, program, welding method, and additional manufacturing method involved in the present invention will be described in detail based on the accompanying drawings.

[0040] Furthermore, this embodiment is an example of a case using a welding robot, and the welding control method of the present invention is not limited to the structure of this embodiment. For example, the welding control method of the present invention can be applied to an automatic welding device using a trolley, or it can be applied to a mobile small welding robot. In addition, in this embodiment, a gas metal arc welding method utilizing pulse waveforms is used.

[0041] Therefore, in this embodiment, a gas metal arc welding method using the welding control method of the present invention will be described. However, the welding control method of the present invention can also be applied to additional manufacturing methods using gas metal arc welding.

[0042] Furthermore, the method for measuring the welding behavior involved in this invention is useful not only in welding but also in add-on manufacturing techniques utilizing GMAW, specifically wire and arc additive manufacturing (WAAM). Additionally, while the term add-on manufacturing is sometimes used broadly in the context of WAAM or rapid prototyping, it is used uniformly throughout this invention. When the method involved in this invention is applied to add-on manufacturing techniques, "welding" is referred to as "deposition," "add-on manufacturing," or "deposition," etc. For example, when processed as welding, it is called "welding behavior," but when the invention is used as add-on manufacturing, it is called "deposition behavior"; when processed as welding, it is called "welding system," but when the invention is used as add-on manufacturing, it can be called "add-on manufacturing system."

[0043] <Overview of Welding Systems>

[0044] Figure 1 This is a schematic diagram showing a structural example of the welding system according to this embodiment. The welding system 50 includes a welding robot 110, a welding control device 120, a feed device (not shown) for feeding welding wire 100, a welding power source 140, and a controller 150.

[0045] The welding power source 140 is connected to the welding robot 110 via a positive power cable (not shown) to energize the welding wire 100, which serves as a consumable electrode, and is connected to the workpiece (hereinafter also referred to as "base material") 200 via a negative power cable (not shown). This connection is for welding with opposite polarities; in the case of welding with positive polarity, the welding power source 140 simply needs to be reversed.

[0046] In addition, the welding power source 140 and the feeding device for feeding the welding wire 100 are connected by a signal wire, which can control the feeding speed of the welding wire.

[0047] The welding robot 110 has a welding torch 111 as an end effector. The welding torch 111 has an energizing mechanism, namely a welding nozzle, for energizing the welding wire 100. The welding wire 100 generates an electric arc from its tip by energizing the welding nozzle, and uses this heat to weld the workpiece 200, which is the object to be welded. In addition, the welding nozzle is sometimes also referred to as a conductive nozzle.

[0048] Furthermore, the welding torch 111 is equipped with a protective gas nozzle that serves as a mechanism for ejecting the protective gas. The protective gas can be any gas composition that exhibits droplet transfer characteristics in the controlled manner used in this embodiment; specifically, it preferably includes at least one of carbon dioxide, nitrogen, hydrogen, and oxygen, which have a high potential gradient. Moreover, from a generality point of view, it is more preferable to use carbon dioxide alone, and in the case of a mixed gas with argon (hereinafter also referred to as "Ar gas"), it includes at least one of carbon dioxide, nitrogen, hydrogen, and oxygen; more preferably, the total volume percentage of gases other than Ar gas is 5 to 50%. Additionally, the protective gas is supplied by a protective gas supply device not shown in the figure.

[0049] The welding wire 100 used in this embodiment is not particularly limited; for example, it can be either a solid wire without flux or a flux-coated wire with flux. Furthermore, the material of the welding wire 100 is not limited; for example, it can be mild steel, stainless steel, aluminum, titanium, or its surface can be plated with Cu, etc. Moreover, the diameter of the welding wire 100 is not particularly limited. In this embodiment, it is preferable to set the upper limit of the diameter to 1.6 mm and the lower limit to 0.8 mm.

[0050] Furthermore, in this embodiment, the specific structure of the workpiece 200 is not particularly limited, nor are the construction conditions such as the joint shape, welding posture, and bevel shape particularly limited.

[0051] The welding control device 120 primarily controls the movements of the welding robot 110. The welding control device 120 pre-stores teaching data that determines the welding robot 110's movement mode, welding start position, welding end position, welding conditions, oscillation movements, etc., and instructs the welding robot 110 to control its movements. Furthermore, according to the teaching data, the welding control device 120 supplies welding conditions such as welding current, welding voltage, and feed rate to the welding power source 140 during the welding operation.

[0052] In addition, such as Figure 1 As shown, the welding system 50 in this embodiment is configured with the welding control device 120 and the welding power source 140 being independent, but it can also be configured with the welding control device 120 included in the welding power source 140.

[0053] The controller 150 is connected to the welding control device 120 to create and display programs for the welding robot 110, input teach data, and provide these programs to the welding control device 120. Furthermore, the controller 150 also has the function of manually operating the welding robot 110. The connection between the controller 150 and the welding control device 120 can be wired or wireless.

[0054] The welding power source 140 supplies power to the welding wire 100 and the workpiece 200 according to instructions from the welding control device 120, thereby generating an electric arc between the welding wire 100 and the workpiece 200. In addition, the welding power source 140 outputs a signal to a feed device (not shown) to control the speed of feeding the welding wire 100 according to instructions from the welding control device 120.

[0055] <Functional Structure of Welding Power Source>

[0056] Next, refer to Figure 2 The functional structure of the welding power source 140 involved in this embodiment will be described in detail. Figure 2 This is a block diagram showing the general structure of the power control unit in the welding power source 140.

[0057] The control system portion of the welding power source 140 is executed, for example, by a welding control device 120 or a computer program (not shown).

[0058] The control system of the welding power source 140 includes a current setting unit 36. In this embodiment, the current setting unit 36 ​​has the function of setting various current values ​​of the welding current that is specified to flow in the welding wire 100, and also has the function of setting the start time and end time of the period during which the welding current value is suppressed by the current suppression period setting unit 36A, and the function of obtaining information on the tip position of the welding wire 100 by the wire tip position changing unit 36B.

[0059] Additionally, the non-suppression period T described later... IP Various condition settings, such as the rising interval T U The descending interval T D The current setting point and other functions include the function of setting various current values ​​of the specified welding current in the current setting unit 36.

[0060] In this embodiment, the welding current represents the alternating repetitive current non-suppression period T. IP and current suppression period T IB The pulse waveform of the welding current. Furthermore, the current setting unit 36 ​​sets the current non-suppression period T. IP The set current value Ip (hereinafter also referred to as "peak current Ip") and the current suppression period T IBThe set current value Ib (hereinafter also referred to as "base current Ib") is used. Alternatively, a stable current Ia for resetting the droplet detachment timing, described later, can also be set. Furthermore, in this embodiment, the welding current is essentially controlled by two values: the peak current Ip and the base current Ib. Therefore, the start time t1 of the current suppression period represents the start time of the base current Ib, i.e., the base current start time. Furthermore, the end time t2 of the current suppression period represents the end time of the base current Ib, i.e., the base current end time. Additionally, the current non-suppression period T... IP The start time is represented by the peak current start time, and the non-suppression period T. IP The end time can also be expressed as the peak current end time.

[0061] The main power circuit of the welding power supply 140 consists of a three-phase AC power supply (hereinafter also referred to as "AC power supply") 1, a primary side rectifier 2, a smoothing capacitor 3, a switching element 4, a transformer 5, a secondary side rectifier 6, and a reactor 7.

[0062] The AC power input from AC power source 1 is fully rectified by primary-side rectifier 2, and then smoothed by smoothing capacitor 3 to be converted into DC power. Next, the DC power is converted into high-frequency AC power by inverter control via switching element 4, and then converted into secondary-side power by transformer 5. The AC output of transformer 5 is fully rectified by secondary-side rectifier 6, and then smoothed by reactor 7. The output current of reactor 7 is supplied as output from the main power supply circuit to welding nozzle 8, energizing welding wire 100, which serves as a consumable electrode.

[0063] The welding wire 100 is fed by the feed motor 24 and the feed device 130, generating an arc 9 between itself and the base material 200. In this embodiment, the feed motor 24 feeds the welding wire 100 such that during the forward feed period T during which the tip of the welding wire 100 moves toward the base material 200,... P During the reverse feed period T, the tip of the welding wire 100 moves in the opposite direction to that of the base material 200. N Periodic switching.

[0064] Furthermore, the term "wire tip" as used here generally refers to the wire tip without considering the presence of molten droplets hanging from it. That is, the wire molten by the electric arc is considered to be transitioning to the base material. As will be described later, its position is determined by the speed difference between the wire feed rate and the wire melting rate.

[0065] The feed motor 24 controls the feeding of the welding wire 100 by a control signal Fc from the feed drive unit 23. Furthermore, the average feed speed is approximately the same as the melting speed. In this embodiment, the feeding of the welding wire 100 by the feed motor 24 is also controlled by the welding power source 140.

[0066] A voltage setting signal Vr, representing the target value of the voltage applied between the welding nozzle 8 and the base material 200, is supplied from the voltage setting unit 34 to the current setting unit 36. This voltage setting signal Vr is also fed to the voltage comparison unit 35 and compared with the voltage detection signal Vo detected by the voltage detection unit 32. The voltage detection signal Vo is a measured value. The voltage comparison unit 35 amplifies the difference between the voltage setting signal Vr and the voltage detection signal Vo, outputting it as a voltage error amplification signal Va to the current setting unit 36. The current setting unit 36 ​​controls the welding current to keep the length of the arc 9 (hereinafter also referred to as "arc length") constant. In other words, the current setting unit 36 ​​performs constant voltage control by controlling the welding current.

[0067] The current setting unit 36 ​​sets the value of the peak current Ip, the value of the base current Ib, the period during which the peak current Ip is given, or the value of the peak current Ip and the value of the base current Ib based on the voltage setting signal Vr and the voltage error amplification signal Va, and outputs the current setting signal Ir corresponding to the set period or the value to the current error amplification unit 37.

[0068] The current error amplification unit 37 amplifies the difference between the current setting signal Ir, which is given as the target value, and the current detection signal Io detected by the current detection unit 31, and outputs it to the inverter drive unit 30 as the current error amplification signal Ed. The inverter drive unit 30 corrects the drive signal Ec of the switching element 4 using the current error amplification signal Ed.

[0069] The current setting unit 36 ​​is also input with a detachment detection signal Drl, which is a signal used to detect the detachment of a molten droplet from the tip of the welding wire 100. The detachment detection signal Drl is output from the detachment detection unit 33. The detachment detection unit 33 monitors the change in the voltage detection signal Vo output by the voltage detection unit 32 and detects the detachment of the molten droplet from the welding wire 100 based on this change. The detachment detection unit 33 is an example of a detection unit.

[0070] The detachment detection unit 33 here detects droplet detachment, for example, by comparing the value obtained by differentiating or second-order differentiating the voltage detection signal Vo with a detection threshold. The detection threshold is pre-stored in a storage unit (not shown). Alternatively, the detachment detection unit 33 can also generate a detachment detection signal Drl based on the change in resistance calculated from the measured voltage detection signal Vo and the current detection signal Io.

[0071] The current setting unit 36 ​​also assigns an average feed rate Fave to the fed welding wire 100. The average feed rate Fave is output based on the teaching data stored in a storage unit (not shown) in the average feed rate setting unit 20. In other words, the average feed rate Fave can also be referred to as the set value (command value) of the feed rate.

[0072] The current setting unit 36 ​​determines the values ​​of peak current Ip, base current Ib, the start time t1 of base current Ib, and the end time t2 of base current Ib based on the given average feed rate Fave.

[0073] In this embodiment, such as Figure 2 As shown, the average feed rate Fave is input to the current setting unit 36. However, the signal input to the current setting unit 36 ​​can also be replaced by a value related to the average feed rate Fave as the setting value. For example, if a database containing the average feed rate Fave and an average current value that can perform optimal welding for that average feed rate Fave is stored in a storage unit (not shown), the average current value can also be replaced by the average feed rate Fave as the setting value.

[0074] The average feed rate Fave is also provided to the amplitude feed rate setting unit 21 and the feed rate command setting unit 22. Here, the amplitude feed rate setting unit 21 determines the values ​​of amplitude Wf ​​and period Tf based on the input average feed rate Fave. Amplitude feed refers to a feed pattern in which periods of feed rate greater than the average feed rate Fave (i.e., forward feed periods) and periods of feed rate less than the average feed rate Fave (i.e., reverse feed periods) alternate. Furthermore, periods of feed rate less than the average feed rate Fave refer to periods less than the average feed rate Fave, including negative feed rates, i.e., the speed at which the wire tip moves in the opposite direction to the position of the base material 200. Amplitude Wf ​​gives the magnitude of change relative to the average feed rate Fave, and period Tf gives the time of amplitude change as a repeating unit. The amplitude feed rate setting unit 21 generates and outputs an amplitude feed rate Ff corresponding to the determined values ​​of amplitude Wf ​​and period Tf or frequency f.

[0075] The feed rate command setting unit 22 outputs a feed rate command signal Fw based on the amplitude feed rate Ff and the average feed rate Fave. In this embodiment, the feed rate command signal Fw is represented by the following formula.

[0076] Fw = Ff + Fave ... Equation (1)

[0077] However, the feed rate command signal Fw represented by equation (1) is limited to the case where it is detected during the period during which the molten droplet is expected to detach from the tip of the welding wire 100. If the detachment of the molten droplet is not detected during the expected period, the feed rate command setting unit 22 may also switch the feed rate command signal Fw to feed control based on a constant speed. For example, the feed rate command setting unit 22 switches the feed rate command signal Fw to feed based on the average feed rate Fave. The switching from feed based on the average feed rate Fave to feed control represented by equation (1) is determined according to the timing of detecting the detachment of the molten droplet. In addition, specific control examples will be described later.

[0078] The feed rate setting unit 22 detects which phase of the amplitude feed has disengaged based on the disengagement detection signal Drl given by the disengagement detection unit 33.

[0079] The feed speed command signal Fw is output to the phase offset detection unit 26, the feed error amplification unit 28, and the current setting unit 36.

[0080] The feed error amplification unit 28 amplifies the difference between the feed speed command signal Fw, which is the target speed, and the feed speed detection signal Fo, which is the actual feed speed of the feed motor 24 for the welding wire 100, and outputs the speed error amplification signal Fd, which has been corrected for the error, to the feed drive unit 23.

[0081] The feed drive unit 23 generates a control signal Fc based on the speed error amplification signal Fd and sends it to the feed motor 24. The feed speed conversion unit 25 here converts the rotation amount of the feed motor 24 into the feed speed detection signal Fo of the welding wire 100.

[0082] In this embodiment, the phase offset detection unit 26 compares the feed speed command signal Fw with the feed speed detection signal Fo, which is a measured value, and outputs the phase offset time Tθd. Alternatively, the phase offset detection unit 26 can also measure the feed operation of the feed motor 24 when parameters such as period Tf, amplitude Wf, and average feed speed Fave are variable, to determine the phase offset time Tθd.

[0083] The phase offset time Tθd is given to the wire tip position changing unit 36B of the current setting unit 36. The wire tip position changing unit 36B calculates the tip position of the welding wire 100 with the base material 200 as the reference plane based on the feed speed command signal Fw and the phase offset time Tθd, and gives the calculated tip position information to the current suppression period setting unit 36A. Here, the current suppression period setting unit 36A sets the period for suppressing the welding current, that is, the period for controlling the current setting signal Ir to the base value current Ib, based on the tip position information of the welding wire 100, or based on the tip position information of the welding wire 100 and the feed speed command signal Fw.

[0084] The current setting unit 36 ​​here is an example of a control unit that changes the welding current according to the position of the tip of the welding wire 100.

[0085] Basic control of welding current based on information about the tip position of the welding wire or the feed speed command signal Fw.

[0086] The following describes an example of controlling the welding current of the welding power source 140 based on information about the tip position of the welding wire 100 or the feed speed command signal Fw.

[0087] The welding current is controlled by the current setting unit 36 ​​that constitutes the welding power supply 140. As described above, in this embodiment, the current setting unit 36 ​​achieves control by executing a program.

[0088] In this embodiment, the current setting unit 36 ​​controls the switching of the welding current value based on information about the tip position of the welding wire 100 and the feed speed command signal Fw of the welding wire 100. Therefore, before explaining the control of the welding current, the time variation of the feed speed command signal Fw and the time variation of the tip position of the welding wire 100 will be explained.

[0089] Figure 3 This is a waveform diagram illustrating the time-varying change of the feed rate command signal Fw. The horizontal axis represents time (phase), and the vertical axis represents the wire feed rate. The unit of the vertical axis is meters per minute or rotational speed. Figure 3 In this embodiment, a speed greater than the average feed rate Fave is denoted as "forward feed," and a speed less than the average feed rate Fave is denoted as "reverse feed." In this embodiment, the feed rate command signal Fw varies in a sinusoidal shape defined by the period Tf and the amplitude Wf. Hereinafter, the period during which the feed rate is greater than the average feed rate Fave is referred to as the forward feed period T. P Conversely, the period during which the feed rate is smaller than the average feed rate Fave is called the reverse feed period T. N Furthermore, for ease of explanation, the first half of each feed period will be referred to as the "early stage" and the second half as the "late stage".

[0090] Here, the average feed rate Fave can be considered as the wire melting rate Fm. The following is as follows: Figure 3 As shown, sometimes the periodic repetition of the forward feed period T is... P and reverse feed period T N The amplitude feed is called the "initial condition".

[0091] Figure 4 This is a waveform diagram illustrating the time-varying position of the tip of the welding wire 100 (hereinafter also referred to as "wire tip position"). The horizontal axis represents time (phase), and the vertical axis represents the distance (height) from the surface of the base material 200 upwards in the normal direction.

[0092] However, in Figure 4 In this context, the position (height) of the welding wire 100 when fed at the maximum or minimum feed speed is used as the reference distance. Distances larger than the reference distance are represented by positive values, and distances smaller than the reference distance are represented by negative values.

[0093] exist Figure 4 In this context, T0 and T4 represent the time points corresponding to the positions where the tip of the welding wire 100 is closest to the base material surface (hereinafter also referred to as the "lowest point"), and T2 represents the time point corresponding to the positions where the tip of the welding wire 100 is furthest from the base material surface (hereinafter also referred to as the "top point"). The vertex here is an example of the top point.

[0094] like Figure 4 As shown, the period during which the tip of the welding wire 100 approaches the surface of the base material over time, specifically the period during which the tip of the welding wire 100 moves from the top to the bottom, is called the "forward feed period T". P The period during which the tip of the welding wire 100 moves away from the base material surface over time, specifically the period during which the tip of the welding wire 100 moves from the bottom to the top, is called the "reverse feed period T". N ".

[0095] Furthermore, time points corresponding to the reference distance are designated as T1 and T3. T1 is the midpoint between the lowest point (the position closest to the base material surface at the tip of the welding wire 100) and the highest point (the position furthest from the tip). T3, on the other hand, is the midpoint between the highest and lowest points. Figure 4 As shown, the range of change from the reference distance to the top or the bottom is called "amplitude Wf", and the range of change from the top to the bottom is called "wave height Wh".

[0096] In addition, refer to Figure 3 as well as Figure 4It can be seen that when the tip of the welding wire 100 is at the top or bottom, the feed speed of the welding wire 100 is set to a predetermined average feed speed Fave value. Therefore, even if the wire feed speed changes periodically, the melting speed of the wire and the wire feed speed are balanced, the arc length is approximately constant, and continuous and stable welding can be achieved.

[0097] Figure 5 This is a flowchart illustrating an example of basic control of welding current in this embodiment. Figure 5 The control shown is in Figure 2 The current setting unit 36 ​​described herein is executed. Additionally, the symbol S in the figure indicates a step. Figure 5 The control shown corresponds to a one-cycle change in the position of the tip of the welding wire 100. Therefore, in Figure 5 In this embodiment, the state at time point T0 is taken as step 1. The current setting unit 36 ​​calculates the tip position of the welding wire 100 to control the current setting signal Ir. The average feed rate Fave is equal to the wire melting rate Fm. Therefore, by integrating the difference between the feed rate command signal Fw and the wire melting rate Fm (≈ Fave), the tip position of the welding wire 100 can be determined. Therefore, the current setting unit 36 ​​sets the tip position of the welding wire 100 based on the following formula.

[0098] Position of the wire tip = ∫(Fw-Fave)·dt···Equation (2)

[0099] In addition, the change in the front end position calculated by equation (2) is related to Figure 4 correspond.

[0100] However, in the feeding of welding wire 100, the use of... Figure 2 In the case of the feed motor 24 described herein, a phase shift sometimes occurs between the commanded feed speed and the actual feed speed, i.e., the feed speed detection signal Fo. Therefore, the current setting unit 36 ​​corrects the base current start time t1 based on the phase shift time Tθd given by the phase shift detection unit 26, wherein the base current start time t1 is calculated corresponding to the tip position of the welding wire 100, and the tip position of the welding wire 100 is calculated based on the average feed speed Fave and the feed speed command signal Fw. Specifically, the value of the base current start time t1 is then set as shown in the following formula.

[0101] t1=t1+Tθd···Equation (3)

[0102] Similarly, the current setting unit 36 ​​corrects the base current end time t2 calculated based on the average feed rate Fave and the feed rate command signal Fw based on the phase offset time Tθd.

[0103] t2=t2+Tθd···Equation (4)

[0104] Here, we have explained the case where the start time t1 and end time t2 of the base current are controlled from the perspective of feed rate, but the same applies from the perspective of position control.

[0105] Figure 6 This is a diagram illustrating a control example where the current setting signal Ir represents the specified welding current value. The horizontal axis represents time, and the vertical axis represents the current detection signal Io. The time points T0, T1, T2, T3, and T4 in the diagram correspond to... Figure 4 The time points T0, T1, T2, T3, and T4 are determined based on the tip position of the welding wire 100, which is calculated from the average feed rate Fave at the tip position of the welding wire 100 and the feed rate command signal Fw.

[0106] like Figure 6 As shown, the base current start time t1 represents the time point T0 when the tip of the welding wire 100 is at its lowest point, i.e., from the positive feed period T. P During the switch to reverse feed period T N The phase is delayed by a specific point in time. Additionally, in Figure 6 In this context, t1' represents the maximum value of the base current starting time t1.

[0107] Here, return Figure 5 The explanation is as follows. As shown in step 2, if the tip of the welding wire 100 is at its lowest point, which is time point T0, the current setting unit 36 ​​determines whether the time T measured from time point T0 is greater than or equal to the base current start time t1. During the period when the determination result in step 2 is negative (False), as shown in step 3, the current setting unit 36 ​​continues to output the peak current Ip as the current setting signal Ir. This period corresponds to... Figure 6 During the non-suppression period of the current T IP .

[0108] Next, as Figure 5 As shown, when the determination result of step 2 is affirmative (True), as shown in step 4, the current setting unit 36 ​​starts outputting the base value current Ib as the current setting signal Ir. As described above, at the time point when the switching to the base value current Ib begins, the feed of the welding wire 100 has already switched to reverse feed during the T period. N The tip of the welding wire 100 begins to move away from the surface of the base material.

[0109] Near time point T0, when the tip of the welding wire 100 is at its lowest point, the molten droplet is located near the molten pool, thus shortening the arc length. Furthermore, after time point T0, during the period of switching to reverse feed, T... NThat is, the tip of the welding wire 100 is moved to be lifted. The growing droplet as a whole has an inertial force in the positive feed direction, that is, the direction close to the base material 200. In contrast, the welding wire 100 moves in the opposite direction, that is, away from the base material 200. Therefore, the droplet further changes into a hanging shape, which further promotes detachment.

[0110] Furthermore, by switching the welding current value to the base current Ib during the predicted detachment period, the arc reaction force can be reduced compared to the period when the peak current Ip is supplied. As a result, the force lifting the molten droplet is further weakened, making it easier for the droplet to form a drooping shape. Thus, by suppressing the welding current during the current suppression period T... IB By causing the molten droplets to detach from the tip of the welding wire 100, a reduction in sputtering can be expected.

[0111] Return again Figure 5 The explanation is as follows. As shown in step 5, the current setting unit 36, which switches the current setting signal Ir to the base value current Ib, determines whether the time T is greater than or equal to the base value current end time t2. Figure 6 In this context, t2' represents the maximum value of the base current end time t2. During the period when the determination result in step 5 is negative (False), as shown in step 4, the current setting unit 36 ​​outputs the base current Ib as a current setting signal Ir. After the supply of the base current Ib begins, the tip of the welding wire 100 moves so that it is lifted to the apex, i.e., the position where the tip is furthest from the base material 200, as the molten droplet detaches.

[0112] After the droplet detaches, in order to melt the welding wire 100 and form a droplet, it is necessary to end the supply period of the base current Ib, i.e., the current suppression period T. IB The period during which the peak current Ip is switched to be supplied, i.e., the period during which the current is not suppressed, T. IP Therefore, it is preferable that the supply of the base current Ib ends during the time period T1 to T2.

[0113] When the determination result of step 5 is affirmative (True), as shown in step 6, the current setting unit 36 ​​begins to output the peak current Ip as the current setting signal Ir. Next, as shown in step 7, the current setting unit 36 ​​determines whether the time T measured from time point T0 is time point T4. During the period when the determination result of step 7 is negative (False), as shown in step 6, the current setting unit 36 ​​outputs the peak current Ip as the current setting signal Ir. On the other hand, if the determination result of step 7 is affirmative (True), the current setting unit 36 ​​returns to step 1. Through the above control, the current setting signal Ir becomes a pulse waveform of periodically repeating peak current Ip and base current Ib.

[0114] <Control methods for droplet detachment>

[0115] The above description constitutes the basic control of the welding current of the welding power source 140 based on information about the tip position of the welding wire 100 or the feed speed command signal Fw. In actual welding, under construction conditions and in welding environments with interference, the expected detachment may not occur.

[0116] In this embodiment, the values ​​of frequency f and peak current Ip (i.e., the non-suppression period of current T) are determined under the conditions described in the following detailed description. IP The set current, the base current Ib, and the current suppression period T IB Setting current, current non-suppression period T IP (Also known as the "peak current period"). Current suppression period T IB (Also known as the "base current period"). Forward feed period T P During the reverse feed period T N By implementing control measures, droplet detachment can be controlled with greater precision.

[0117] In addition, during the non-suppression period of the current T IP The set current, or the current suppression period T IB The set current is not limited to a fixed value and can be changed during various periods. Therefore, T represents the period during which the current is not suppressed. iP During the overall or current suppression period T IB The overall thermal energy index is expressed as T during the non-suppressed current period. IP Or during the current suppression period T IB The average current is used to represent the current during the non-suppressed period T. IP The average current is expressed as "I P-AVE "During the current suppression period T" IB The average current is expressed as "I B-AVF ".

[0118] The following is a detailed explanation of each control element.

[0119] (Frequency f: 50~150Hz)

[0120] This will make the forward feed period T P During the reverse feed period T N The combined period is defined as a cycle, and its frequency f is controlled to suppress short circuits by stably detaching or dripping the molten droplets formed at the tip of the welding wire. This frequency f, as a condition described later—namely, maintaining the weld penetration depth and forming the optimal droplet size—is set in the range of 50–150 Hz.

[0121] At frequencies below 50 Hz, although excessively large droplets are formed at the wire tip, the inertial force acting on the droplets is insufficient. Therefore, the large droplets easily contact the molten pool and are difficult to detach. As a result, short circuits increase, leading to increased sputtering and an inability to achieve a stable melt depth.

[0122] On the other hand, if the frequency f exceeds 150 Hz, the droplet formed at the tip of the wire will not fully grow to its optimal size, and the inertial force will be insufficient. Therefore, during the current suppression period T... IB Stable detachment is impossible. Therefore, the molten droplet detaches at unexpected times, causing short circuits or sputtering.

[0123] Therefore, the frequency f is specified to be in the range of 50 to 150 Hz, preferably 60 to 130 Hz, and more preferably 70 to 120 Hz.

[0124] Furthermore, the droplet size suitable for the aforementioned frequency f is preferably 1.7 to 5.0 mm in terms of average volume. 3 The droplet size mentioned here refers to the size of the droplet before it detaches from the molten droplet. Examples include methods such as calculating the volume based on the melting rate Fm, or calculating the volume based on two-dimensional images obtained from images taken by a vision sensor from one or more directions. For instance, the average volume before detachment is 1.7–5.0 mm. 3 Within this range, short circuits can be suppressed more effectively, and sputtering can be reduced effectively, as well as the penetration depth can be stabilized.

[0125] (0.65≤I P-AVE / (I P-AVE +I B-AVE ≤0.90)

[0126] I P-AVE Compared to the current non-suppression period T IP Average current and current suppression period T IB Average current I B-AVE The ratio of the sum of, i.e., I P-AVE / (I P-AVE +I B-AVE The range is 0.65 to 0.90.

[0127] If the above ratio is less than 0.65, then during the non-suppressed current period T IP During the current suppression period T, the electromagnetic constriction force acting on the molten droplet decreases, and the current suppression period T IB In the molten droplet, inertial force alone is insufficient for detachment, leading to timing deviations and a tendency to short-circuit. Furthermore, this short-circuit causes sputtering, resulting in inconsistent melt depth. Additionally, during the non-suppressed current period T... IPIn this process, there is a tendency for the thermal energy to decrease, resulting in a particularly shallow melting depth.

[0128] On the other hand, if the aforementioned ratio exceeds 0.90, then during the non-suppressed current period T IP In this process, the droplet size becomes too large, and the arc pressure applied to the droplet (hereinafter referred to as "arc reaction force" in the context of arc pressure applied to the droplet) becomes too large, causing the pushed droplet to detach in a direction different from the molten pool, thus easily producing large-particle sputtering. In addition, arc depletion and long-term short circuits are also prone to occur, thus causing sputtering and making it impossible to obtain a stable melt depth.

[0129] Therefore, I P-AVE / (I P-AVE +I B-AVE The value is specified in the range of 0.65 to 0.90, preferably 0.70 to 0.85.

[0130] (Wave height Wh: 14-35% relative to the distance between the nozzle and the base material)

[0131] like Figure 4 As shown, the wave height Wh, which represents the variation in the position of the tip of the welding wire 100 between the uppermost and lowermost ends, is in the range of 14% to 35% relative to the nozzle-base material distance. For example, when the nozzle-base material distance is 25 mm, the wave height Wh should be set in the range of 3.75 mm to 8.75 mm.

[0132] If the aforementioned wave height Wh is outside the range of 14% to 35% of the distance between the nozzle and the base material, short circuits cannot be prevented. Furthermore, the "reference distance" that serves as the reference position for the wave height Wh and amplitude Wf ​​can be arbitrarily set.

[0133] (0.30≤T IB / (T IP +T IB ≤0.60)

[0134] Relative to any current non-suppression period T IP With the subsequent current suppression period T IB The sum of the currents during the suppression period T IE The ratio, that is, T IE / (T IP +T IB The range is 0.30 to 0.60.

[0135] If the above ratio is less than 0.30, then during the current suppression period T IB During the period when the molten droplet formed at the tip of the wire is not completely detached, it is susceptible to current non-suppression during the T period. IPThe electric arc reaction force causes the circuit to break away simultaneously, which increases short circuits, increases sputtering, and prevents the achievement of a stable melt depth.

[0136] On the other hand, if the above ratio exceeds 0.60, the electromagnetic clamping force is insufficient, therefore during the current suppression period T... IB Stable detachment is impossible. Therefore, the molten droplet detaches at unexpected times, causing short circuits or sputtering.

[0137] Therefore, T IB / (T IP +T IB The value is specified in the range of 0.30 to 0.60, preferably 0.31 to 0.58, and more preferably 0.31 to 0.52.

[0138] (0.40≤T N / (T P +T N ≤0.70)

[0139] Relative to the forward feed period T P During the reverse feed period T N The sum of the reverse feed period T N The ratio, i.e., T N / (T P +T N The range is 0.40 to 0.70.

[0140] If the ratio mentioned above is less than 0.40, sufficient time for droplet detachment cannot be obtained during the current suppression period T. IB Stable detachment is impossible. Therefore, the molten droplet detaches at unexpected times, causing short circuits or sputtering.

[0141] On the other hand, if the above ratio exceeds 0.70, the droplets formed at the wire tip will extend finely during the reverse feed T. N Before starting, short circuits are prone to occur. Therefore, T N / (T P +T N The value is specified in the range of 0.40 to 0.70.

[0142] {T N / (T P +T N )}>{T IB / (T IP +T IB )}

[0143] Relative to the forward feed period T p During the reverse feed period T N The sum of the reverse feed period T NThe ratio is {T} N / (T P +T N )}, and relative to the current non-suppression period T IP During the current suppression period T IB The sum of the currents during the suppression period T IB The ratio is {T} IB / (T IP +T IB Let the relationship between {T} be {T} N / (T P +T N )}>{T IB / (T IP +T IB )}.

[0144] If {T N / (T P +T N The value of )} is {T IB / (T IP +T IB If the value of )} is below, the timing of the electric arc force when the tip of the wire approaches the molten pool before reverse feeding becomes insufficient, and the melting depth becomes shallower.

[0145] That is, when there is sufficient arc pressure before and after the wire tip is at the bottom, even assuming a short average arc length, sufficient penetration depth can be obtained by achieving a short-circuit-free submerged arc state. However, as mentioned above, if the timing before and after the wire tip is at the bottom is the current suppression period T... IB If the electric arc pressure is insufficient, the molten droplets are prone to short-circuiting with the molten pool, resulting in insufficient melting depth.

[0146] In addition, submerged arc refers to the state in which an electric arc is generated by the wire penetrating into the molten pool due to strong arc pressure. Generally speaking, the higher the welding current, the stronger the arc pressure.

[0147] (During the period of non-suppression of current T) IP During the positive feed period T P (more than 2 / 3 of the period)

[0148] Requires current during non-suppression period T IP This period accounts for more than two-thirds of the time during which the tip of the welding wire 100 moves from the top to the bottom. Here, the period during which the wire tip moves from the top to the bottom, as described above, refers to the forward feed period T. P .

[0149] Here, refer to Figure 7 as well as Figure 8 Please provide an explanation. Figure 7These are continuous photographs taken by a high-speed camera, showing an example of the welding progress in a conventional short-circuit transfer method, along with the advance or retraction of the welding wire, the period of non-current suppression, and the period of current suppression. They are substitute photographs for each elapsed time in Test No. 24, the reference example described later. Furthermore, Figure 8 These are continuous photographs taken by a high-speed camera showing an example of the progress of welding in this embodiment, along with the advance or retreat of the welding wire, the period of non-current suppression, and the period of current suppression. They are substitute photographs for each elapsed time in the embodiment described later, namely Test No. 8.

[0150] like Figure 7 As shown, in the conventional short-circuit transition wire feed control, the forward feed period T, indicated by "forward" in the figure, is... P The time is approximately 8.4ms, ranging from 0ms to around 8.4ms. In contrast, the forward feed period T... P During the non-suppression period of the current T IP The time interval is approximately 2.4ms, ranging from 0ms to around 2.4ms. Therefore, the forward feed period T... P During the non-suppression period of the current T IP The proportion is less than 1 / 2.

[0151] Thus, in the previous short-circuit transition method of wire feed control, by controlling the forward feed period T... P During the non-suppression period of the current T IP When the ratio is controlled to be less than 1 / 2, low-sputter welding can be performed. As a result, the arc pressure does not act on the molten pool, thus the penetration depth becomes shallower.

[0152] On the other hand, such as Figure 8 As shown, in the wire feed control involved in this embodiment, the forward feed period T P The time is approximately 8.4ms, ranging from 0ms to 8.4ms. In contrast, the forward feed period T... P During the non-suppression period of the current T IP The forward feed time is approximately 7.2ms, ranging from 0ms to around 7.2ms. P During the non-suppression period of the current T IP They account for more than two-thirds.

[0153] Thus, in the wire feed control involved in this embodiment, by controlling the forward feed period T... P During the non-suppression period of the current T IP The ratio is controlled to be more than 2 / 3. As the wire tip approaches the molten pool, the sufficient arc pressure penetrates the molten pool, thus increasing the melting depth.

[0154] Next, the preferred conditions in this embodiment will be described in detail.

[0155] like Figure 9A As shown, during the non-suppressed current period T IP The preferred current control is divided into the following intervals: from the base current change to a predetermined current value, followed by the current suppression period T. IB The subsequent upward range T U The period T immediately following the current suppression from the change of the predetermined current value to the base current. IB The previous descending range T D ; and the rising interval T U and the descending interval T D The current control range T outside C .

[0156] The rising interval T U For the purpose of adjusting droplet size or promoting droplet detachment, it is preferable to select the droplet size relative to the non-suppressed current period T. IP The proportion, i.e., "(the rising interval T)" U / Current non-suppression period T IP The value of "()×100%" is below 20%. Additionally, the rising interval T... U The way the welding current value increases can also be Figure 9A The abrupt change shown, in other words, the rising interval T U Compared to the current non-suppression period T IP The proportion is infinitely close to 0%.

[0157] Furthermore, the falling interval TD is intended to adjust the droplet size before reverse feeding, and is preferably relative to the current non-suppression period T. IP The proportion, i.e., "(decreasing interval T)" D / Current non-suppression period T IP The value of "()×100%" is below 20%. Additionally, the decreasing interval T... D The way the welding current value decreases can also be Figure 9A The sharp change shown, in other words, the decrease in the TD interval relative to the current non-suppression period T IP The proportion is infinitely close to 0%.

[0158] Additionally, the rising range T U The descending interval T D It can vary individually in a straight line, a curve, or a step, or it can be a combination of them.

[0159] Next, as Figure 9A As shown, it is preferable to be in the current control range T CAt least two welding current settings are set. Here, the two welding current settings are set as the first welding current setting I. P1 and the second welding current setting value I P2 .

[0160] Furthermore, when the value is set to 0 degrees based on the uppermost position of the welding wire 100, the first welding current setting value I is used as the reference. P1 For timing, the first welding current set value I is preferably set. P1 The end position of the range is set below 20 degrees. This is achieved by setting the first welding current value I... P1 Setting the end position of the range below 20 degrees can suppress the shaking of the molten droplets that are beginning to form, and can maintain a more stable detachment.

[0161] Furthermore, when the value is set to 0 degrees with the uppermost position of the welding wire 100 as a reference, the second welding current setting value I is used for setting. P2 For timing, it is preferable to set the second welding current value I. P2 The end position of the range is set in the range of 135 to 220 degrees. This is achieved by setting the second welding current value I... P2 Setting the end position of the range to 135–220 degrees allows the arc pressure to act effectively on the molten pool, resulting in a stable melting depth.

[0162] Furthermore, such as Figure 9B As shown, when the welding current setting value I is... P2 The end of the range is set as the current control interval T. c At the end, set the welding current value I P2 When the end position of the range is set to Xdeg, it is preferable to set the current suppression period T. IB The end position is set in the range of (X+100) to (X+220) degrees. This is achieved by suppressing the current during the T period. IB The end position is set in the range of (X+100) to (X+220) degrees, and during the current suppression period T IB It includes the timing when inertial forces are most effective, and is therefore preferred from the viewpoint of stabilizing droplet detachment.

[0163] With the first welding current setting value I P1 The preferred welding current is in the range of 250 to 600 A, with the second welding current setting value I. P2 The preferred welding current is in the range of 300–650 A. This is achieved by setting the first welding current value I. P1 and the second welding current setting value I P2The set currents are respectively set to the above ranges, which can further improve the performance of the first welding current set value I. P1 and the second welding current setting value I P2 The effect obtained.

[0164] Additionally, using the second welding current setting value I P2 The set welding current is always higher than the first welding current setting value I. P1 The maximum value of the welding current is set.

[0165] Preferably in the current control range T C Specifically, at the first welding current setting value I P1 Second welding current setting value I P2 During the welding process, the external characteristics of the welding power source are set. More specifically, by setting the external characteristics of the welding power source within the range of 0.05V to 20V / 100A, even in cases of significant length variations during welding, the arc length can be controlled to remain approximately constant by varying the welding current.

[0166] From the perspective of adjusting the droplet size, the optimal current non-suppression period T is preferred. IP Average current I P-AVE The current range is 300–650A. Furthermore, the current suppression period T... IB Average current I B-AVE The range is 80–150 A. Furthermore, from the viewpoint of adjusting the droplet size, the current non-suppression period T is preferred. IP The duration is in the range of 3.0–12.0 ms. Furthermore, the current suppression period T... IB The range is 2.0 to 9.0 ms.

[0167] Additionally, during the forward feed period T P and the reverse feed period T N The preferred range is based on the frequency f and {T} mentioned above. N / (T P +T N The period calculated within their respective defined ranges.

[0168] Example

[0169] The present invention will be described in more detail below with examples. The present invention is not limited to these examples, and modifications can be made to implement it within the scope of the spirit of the invention; all such modifications are included within the technical scope of the present invention.

[0170] [1. Preliminary Test]

[0171] First, before the formal test shown below, a preliminary test on the relationship between the number of short circuits and the penetration depth is conducted.

[0172] Figure 10 It is a graph used to show the relationship between the number of short circuits and the penetration depth. Figure 10 The upper photograph is a cross-sectional view of the welded section taken under welding conditions of 309A welding current, 36.7V welding voltage, and 50cm / min welding speed, with a short-circuit frequency of 97.7 times / second. Furthermore, Figure 10 The lower layer of the photograph shows a cross-sectional view of the welded section under welding conditions of 307A welding current, 36.8V welding voltage, and 50cm / min welding speed, with a short-circuit frequency of 9.6 times / second.

[0173] These cross-sectional photographs show a correlation between the number of short-circuit cycles and the weld penetration depth. In the lower-layer test examples with significantly fewer short-circuit cycles, the weld penetration depth was deeper. Furthermore, visual inspection confirmed that fewer short-circuit cycles resulted in less spatter. That is, it is believed that fewer short-circuit cycles lead to a stable weld penetration depth and reduced spatter. Based on the above, in the following formal tests, the results of the short-circuit cycle count will be used to determine whether a stable weld penetration depth and reduced spatter have been achieved.

[0174] [2. Formal Trial]

[0175] Next, as an experiment to confirm the effectiveness of the welding control method involved in the present invention, various tests of the comparative examples shown below were conducted.

[0176] <Common Welding Conditions>

[0177] The common welding conditions are as follows.

[0178] Welding wire: Soft steel solid wire

[0179] Base material: SS400 (General structural rolled steel JIS G 3101:2004)

[0180] Welding speed of welding wire: 40cm / min

[0181] Welding method: Flat plate overlay welding

[0182] <Evaluation Methods>

[0183] As explained in [1. Preliminary Test] above, the number of short-circuit cycles is considered to be related to whether a stable penetration depth and sputtering reduction have been achieved. Therefore, the stable penetration depth and sputtering reduction were evaluated based on the number of short-circuit cycles. In the formal test, a short-circuit cycle of 5.0 cycles / second or less was rated A (Excellent), a short-circuit cycle of more than 5.0 cycles / second but less than 10.0 cycles / second was rated B (Good), and a short-circuit cycle of more than 10.0 cycles / second was rated C (Unacceptable).

[0184] The test results, along with welding conditions other than the common test conditions, are shown in Tables 1 and 2.

[0185] [Table 1]

[0186]

[0187] [Table 2]

[0188]

[0189] As shown in Tables 1 and 2, experiments No. 1 to No. 10 are embodiments that fully satisfy the requirements of the present invention, resulting in a very low number of short circuits. Therefore, this demonstrates a deep penetration depth and low sputtering volume. On the other hand, experiments No. 11 to No. 23 are comparative examples that do not satisfy at least some of the requirements of the present invention, all resulting in a very high number of short circuits. Therefore, this demonstrates a shallow penetration depth and high sputtering volume.

[0190] Additionally, in Table 1, the values ​​for "Frequency f (Hz)", "(Wave height Wh / mouth-base material distance) × 100 (%)", and "I" are also specified. P-AVE / (I P-AVE +I B-AVE ) "T" IB / (T IP +T IB ) "T" N +(T P +T N ) "{T N / (T P +T N )}>{T IB / (T IP +T IB In the phrase “)}”, numerical values ​​are underlined to indicate values ​​that do not fall within the scope of this invention.

[0191] Furthermore, test No. 24 in Table 1 uses Figure 8 In the reference example of the feed process based on the conventional short-circuit transition method described above, the current non-suppression period T is not satisfied. IP During the positive feed period TP Examples of conditions for a period of more than 2 / 3.

[0192] The following is a detailed examination of each experiment.

[0193] Test No. 1, as an example, satisfies all the requirements of the present invention, especially since the frequency f is 60Hz, which is within the range of 50 to 150Hz. Therefore, the inertial force acts on the front end of the wire, resulting in fewer short circuits, thus earning a B rating.

[0194] Test No. 2, as an example, satisfies all the requirements of the present invention, especially since the frequency f is 130Hz, which is within the range of 50 to 150Hz. Therefore, the inertial force acts on the front end of the wire, resulting in fewer short circuits, thus achieving an A rating.

[0195] Test No. 3, as an example, satisfies all the requirements of the present invention. In particular, the value of {(wave height Wh / distance between nozzle and base material) × 100} is 15%, which meets the range of 14-35%. Therefore, the inertial force acts on the tip of the wire, and the number of short circuits is small, thus it is rated as B.

[0196] Test No. 4, as an example, satisfies all the requirements of the present invention. In particular, the value of {(wave height Wh / distance between nozzle and base material) × 100} is 32%, which is within the range of 14-35%. Therefore, the inertial force acts on the tip of the wire, resulting in fewer short circuits, thus achieving an A rating.

[0197] As an example, Experiment No. 5 satisfies all the requirements of the present invention, especially {I} P-AVE / (I P-AVE +I B-AVE The value is 0.67, which falls within the range of 0.65 to 0.90. Therefore, the droplet size is appropriate, the electromagnetic clamping force plays an effective role, and the number of short circuits is low, thus qualifying as a B rating.

[0198] As an example, Experiment No. 6 satisfies all the requirements of the present invention, especially {I} P-AVE / (I P-AVE +I B-AVE The value is 0.88, which falls within the range of 0.65 to 0.90. Therefore, the droplet size is appropriate, the electromagnetic clamping force plays an effective role, and the number of short circuits is low, thus qualifying as a B rating.

[0199] As an example, Experiment No. 7 satisfies all the requirements of the present invention, especially {T} IB / (T IP +T IB The value is 0.31, which meets the range of 0.30 to 0.60. Therefore, the droplet size is appropriate, the electromagnetic clamping force plays an effective role, and the number of short circuits is low, thus achieving an A rating.

[0200] As an example, Experiment No. 8 satisfies all the requirements of the present invention, especially {T} IB / (T IP +T IB The value is 0.58, which falls within the range of 0.30 to 0.60. Therefore, the droplet size is appropriate, the electromagnetic clamping force plays an effective role, and the number of short circuits is low, thus qualifying as a B rating.

[0201] As an example, Experiment No. 9 satisfies all the requirements of the present invention, especially {T} N +(T P +T N The value of 0.40 satisfies the range of 0.40 to 0.70, so the inertial force is effectively applied to the front end of the wire, resulting in fewer short circuits, thus achieving an A rating.

[0202] As an example, Experiment No. 10 satisfies all the requirements of the present invention, especially {T} N +(T P +T N The value of 0.70 satisfies the range of 0.40 to 0.70, so the inertial force is effectively applied to the front end of the wire, resulting in fewer short circuits, thus achieving an A rating.

[0203] On the other hand, the frequency f of test No. 11, which is a comparative example, is 45 Hz, which is less than the range specified in this invention. Therefore, the inertial force acting on the tip of the wire is insufficient, and the molten droplet cannot be detached. As a result, there are many short circuits, which is rated as C.

[0204] As a comparative example, the frequency f of test No. 12 was 155 Hz, which exceeded the range specified in this invention. Therefore, the droplet size was too small, the inertial force acting on the tip of the wire was insufficient, and the droplet could not detach. As a result, there were many short circuits, and it was rated C.

[0205] As a comparative example, Test No. 13 had a value of 13% for {(wave height Wh / distance between end and base material) × 100}, which is less than the range specified in this invention. Therefore, the inertial force acting on the tip of the wire was insufficient, and the molten droplet could not detach. As a result, there were many short circuits, and it was rated C.

[0206] As a comparative example, Test No. 14 had a {(wave height Wh / nozzle-base material distance) × 100} of 38%, which exceeded the range specified in this invention. Therefore, even with a normal arc length, the short circuit increased, resulting in a high number of short circuits and a C rating.

[0207] As a comparative example, in Test No. 15, the {(wave height Wh / nozzle-base material distance) × 100} was 13%, which is less than the range specified in this invention. Therefore, the inertial force acting on the tip of the wire was insufficient, and the droplet could not detach. In addition, due to {T IB / (T IP +TIB The value of T is 0.22, which is less than the range specified in this invention. Therefore, during the current suppression period, T... IB During the period when the molten droplet formed at the tip of the wire is not completely detached, it is susceptible to current non-suppression during the T period. IP The electric arc reaction force is released simultaneously, short circuits increase, sputtering increases and a stable melt depth cannot be obtained, so the number of short circuits is high, resulting in a C rating.

[0208] As a comparative example, in Test No. 16, the {(wave height Wh / nozzle-base material distance) × 100} was 40%, exceeding the range specified in this invention. Therefore, even with a typical arc length, short circuits increased. Furthermore, {T IB / (T IP +T IB The value of T is 0.14, which is less than the range specified in this invention. Therefore, during the current suppression period, T... IB During the period when the molten droplet formed at the tip of the wire is not completely detached, it is susceptible to current non-suppression during the T period. IP The electric arc reaction force is released simultaneously, short circuits increase, sputtering increases and a stable melt depth cannot be obtained, so the number of short circuits is high, resulting in a C rating.

[0209] As a comparative example, test No. 17 {I P-AVE / (I P-AVE +I B-AVE The value of {T} is 0.60, which is less than the range specified in this invention. Therefore, the electromagnetic pinch force acting on the molten droplet is also small. In addition, {T} N / (T P +T N )}<{T IB / (T IP +T IB Since the conditions specified in this invention are not met, the timing of the electric arc force when the tip of the wire approaches the molten pool before reverse feeding becomes insufficient, which easily leads to short circuits and shallower melting depth. Therefore, the number of short circuits is high, resulting in a C rating.

[0210] As a comparative example, test No. 18 {I P-AVE / (I P-AVE +I B-AVE The value of 0.91 exceeds the range specified in this invention. Therefore, the droplet size is large, and the droplet is repelled and detached due to the reaction force of the electric arc, resulting in arc depletion and long-term short circuit. As a result, the number of short circuits is high, which leads to a C rating.

[0211] As a comparative example, in experiment No. 19, {T} IB / (T IP +T IB The value of T is 0.29, which is less than the range specified in this invention. Therefore, during the current suppression period, T...IB During the non-suppressed current period T, the molten droplet formed at the wire tip does not completely detach and is susceptible to current. IP The electric arc reaction force is released simultaneously, short circuits increase, sputtering increases and a stable melt depth cannot be obtained, so the number of short circuits is high, resulting in a C rating.

[0212] As a comparative example, test No. 20 {T IB / (T IP +T IB The value of T is 0.64, which exceeds the range specified in this invention. Therefore, the electromagnetic clamping force is insufficient during the current suppression period. IB The droplet cannot detach stably, detaching at unexpected times, causing short circuits or sputtering. Furthermore, due to {T} N / (T P +T N )}<{T IB / (T IP +T IB If the conditions specified in this invention are not met, the timing of the electric arc force generated when the front end of the wire fed in reverse approaches the molten pool becomes insufficient, which easily leads to short circuits and shallower melting depth. Therefore, the number of short circuits is high, resulting in a C rating.

[0213] As a comparative example, in experiment No. 21, {T} N +(T P +T N The value of T is 0.35, which is less than the range specified in this invention. Therefore, sufficient time for droplet detachment cannot be obtained during the current suppression period. IB The droplets cannot detach stably, detaching at unexpected times, causing short circuits or sputtering. Furthermore, {T} N / (T P +T N )}<{T IB / (T IP +T IB If the conditions specified in this invention are not met, the timing of the electric arc force generated when the front end of the wire fed in reverse approaches the molten pool becomes insufficient, which easily leads to short circuits and shallower melting depth. Therefore, the number of short circuits is high, resulting in a C rating.

[0214] As a comparative example, in test No. 22, {T} N +(T P +T N The value is 0.75, which exceeds the range specified in this invention. Therefore, the droplets formed at the wire tip are thin and tend to extend. Before the reverse feed begins, short circuits are likely to occur, and the melt depth becomes shallower. As a result, there are many short circuits, which leads to a C rating.

[0215] As a comparative example, experiment No. 23 is {T} N / (T P +T N )}<{T IB / (T IP +T IB If the conditions specified in this invention are not met, the timing of the electric arc force when the tip of the wire approaches the molten pool before reverse feeding becomes insufficient, which easily leads to short circuits and shallower melting depth. Therefore, the number of short circuits is high, resulting in a C rating.

[0216] Furthermore, the present invention is not limited to the above-described embodiments and examples, and can be appropriately modified and improved.

[0217] As stated above, the following matters are disclosed in this specification.

[0218] (1) A welding control method, in gas metal arc welding of a welding wire to which a welding current is supplied, wherein the feed rate of the welding wire is controlled such that the tip of the welding wire moves from the position furthest from the base material (i.e., the uppermost end) to the position closest to the base material (i.e., the lowermost end), i.e., the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N While periodically switching the welding current, the welding current is fed into the base material, and at least based on the tip position of the welding wire or the feed speed signal of the welding wire, the welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB The welding control is performed as follows: the forward feed period T is controlled... P and the reverse feed period T N The combined period is defined as a cycle, and its frequency f is set to 50–150 Hz. The non-suppressed current period T is defined as... IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I p-AVE / (I P-AVE +I B-AVE )≤0.90, the variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, relative to the distance between the tip and the base material of the welding wire, is set to 14-35%, and the arbitrary current non-suppression period T is set to IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IBIf )≤0.60, the forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and during the non-suppression period of the current T IP During the current suppression period T IB The forward feed period T P and the reverse feed period T N The relationship is set as PT N / (T P +T N )}>{T IB / (T IP +T IB Furthermore, during the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

[0219] According to this structure, in an arc welding method that involves periodically repeating forward and reverse feeds at the tip of the wire, it is possible to achieve both stable penetration depth and reduced sputtering.

[0220] (2) According to the welding control method described in (1), the feed rate of the welding wire when the front end of the welding wire is located at the uppermost end or the lowermost end is a predetermined average feed rate value.

[0221] According to this structure, even if the wire feed speed changes periodically, the wire melting speed and the wire feed speed are balanced, the arc length is roughly constant, and continuous and stable welding can be achieved.

[0222] (3) The welding control method according to (1) or (2), wherein the current non-suppression period T IP By the current suppression period T IB The subsequent rising interval, immediately following the current suppression period T IB The previous falling interval, the rising interval, and the current control interval T outside the falling interval. C The rising interval is defined relative to the current non-suppression period T. IP The decrease is below 20%, and the decrease range is relative to the current non-suppression period T. OP It is below 20%.

[0223] According to this structure, in the rising interval T U In the process, it is possible to adjust the droplet size or promote droplet detachment, within the descent range T. DIn this process, the droplet size can be adjusted before reverse feeding.

[0224] (4) According to the welding control method described in (3), wherein, in the current control interval T C It has at least two welding current settings I P1 I P2 When the uppermost position of the welding wire is set to 0 degrees, the welding current setting value I is... P1 The end position of the range is set below 20 degrees, and the welding current setting value I is... P2 The end position of the range is set in the range of 135 to 220 degrees.

[0225] Based on this structure, by setting the first welding current value I... P1 Setting the end position of the range below 20 degrees can suppress the shaking of the molten droplets at the beginning of formation, thus maintaining a more stable detachment. Furthermore, by setting the second welding current value I... P2 Setting the end position of the range to 135–220 degrees allows the arc pressure to act effectively on the molten pool, resulting in a stable melting depth.

[0226] (5) According to the welding control method described in (4), wherein the welding current setting value I is... P2 The end of the range is defined as the current control interval T. C At the end, the welding current setting value I is set. P2 When the end position of the range is set to Xdeg, the current suppression period T is... IB The end position is set in the range of (X+100) to (X+220) deg.

[0227] According to this structure, due to T during the current suppression period IB It includes the timing when inertial forces are most effective, thus enabling the stabilization of droplet detachment.

[0228] (6) The welding control method according to (4) or (5), wherein the welding current setting value I is... P1 The set current is set to 250-600A, and the welding current setting value I is... P2 The set current is set to 300-650A.

[0229] Based on this structure, it is possible to further improve the efficiency of setting the first welding current setting value I. P1 and the second welding current setting value I P2 The effect obtained.

[0230] (7) The welding control method according to any one of (4) to (6), wherein, in the current control interval T C In this process, the external characteristics of the welding power source are set.

[0231] According to this structure, even in cases where there are significant length variations during welding, the arc length can be controlled to remain approximately constant by varying the welding current.

[0232] (8) The welding control method according to any one of (1) to (7), wherein the average volume of the molten droplet detaching from the tip of the welding wire is 1.7 to 5.0 mm. 3 .

[0233] According to this structure, short circuits can be suppressed more effectively, sputtering can be reduced, and a more stable penetration depth can be obtained.

[0234] (9) A welding control device, in gas metal arc welding to which a welding current is supplied, controls the feed rate of the welding wire such that the tip of the welding wire moves from the position furthest from the base material (i.e., the uppermost end) to the position closest to the base material (i.e., the lowermost end), i.e., the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N While periodically switching the welding current, the welding current is fed into the base material, and at least based on the tip position of the welding wire or the feed speed signal of the welding wire, the welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB The welding control device has the function of controlling the forward feed period T as follows: P and the reverse feed period T N The combined period is defined as a cycle, and its frequency f is set to 50–150 Hz. The non-suppressed current period T is defined as... IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE )≤0.90, the variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, relative to the distance between the tip and the base material of the welding wire, is set to 14-35%, and the arbitrary current non-suppression period T is set to IPIP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IBIf )≤0.60, the forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and during the non-suppression period of the current T IP During the current suppression period T IB The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +T IB Furthermore, during the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

[0235] According to this structure, in an arc welding method that involves periodically repeating forward and reverse feeds at the tip of the wire, it is possible to achieve both stable penetration depth and reduced sputtering.

[0236] (10) A welding power source comprising the welding control device described in (9).

[0237] According to this structure, in an arc welding method that involves periodically repeating forward and reverse feeds at the tip of the wire, it is possible to achieve both stable penetration depth and reduced sputtering.

[0238] (11) A welding system comprising the welding control device of (9) or the welding power source of (10).

[0239] According to this structure, in an arc welding method that involves periodically repeating forward and reverse feeds at the tip of the wire, it is possible to achieve both stable penetration depth and reduced sputtering.

[0240] (12) A program that enables a computer of a welding system having at least a welding control device to perform functions in gas metal arc welding of a welding wire, wherein the welding control device controls the feed rate of the welding wire such that the tip of the welding wire moves from the position furthest from the base material (i.e., the uppermost end) to the position closest to the base material (i.e., the lowermost end), i.e., the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. NWhile periodically switching, the welding current is fed into the base material, and at least based on the tip position of the welding wire or the feed speed signal of the welding wire, the welding current is switched and controlled during the non-suppressed current period T. IP Or during the current suppression period T IB In this function, the welding control device is controlled as follows: the forward feed period T is controlled... P and the reverse feed period T N The combined period is defined as a cycle, and its frequency f is set to 50–150 Hz. The non-suppressed current period T is defined as... IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE )≤0.90, the variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, relative to the distance between the tip and the base material of the welding wire, is set to 14-35%, and the arbitrary current non-suppression period T is set to IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB If )≤0.60, the forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and during the non-suppression period of the current T IP During the current suppression period T IB、 The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +T IB Furthermore, during the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

[0241] According to this structure, in an arc welding method that involves periodically repeating forward and reverse feeds at the tip of the wire, it is possible to achieve both stable penetration depth and reduced sputtering.

[0242] (13) A welding method in which gas metal arc welding is performed simultaneously with welding control, wherein in gas metal arc welding in which welding current is supplied to a welding wire, the welding control controls the feed rate of the welding wire such that the tip of the welding wire moves from the position furthest from the base material (i.e., the uppermost end) to the position closest to the base material (i.e., the lowermost end), i.e., the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N While periodically switching the welding current, the welding current is fed into the base material, and at least based on the tip position of the welding wire or the feed speed signal of the welding wire, the welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB The welding control is performed as follows: the forward feed period T is controlled to be such that... P and the reverse feed period T N The combined period is defined as a cycle, and its frequency f is set to 50–150 Hz. The non-suppressed current period T is defined as... IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE )≤0.90, the variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, relative to the distance between the tip and the base material of the welding wire, is set to 14-35%, and the arbitrary current non-suppression period T is set to IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB If )≤0.60, the forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and during the non-suppression period of the current T IP During the current suppression period T IB、 The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +TIB Furthermore, during the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

[0243] According to this structure, in an arc welding method that involves periodically repeating forward and reverse feeds at the tip of the wire, it is possible to achieve both stable penetration depth and reduced sputtering.

[0244] (14) An auxiliary manufacturing method, wherein the auxiliary manufacturing is performed simultaneously with welding control, wherein in the auxiliary manufacturing using gas metal arc welding in which welding current is supplied to the welding wire, the welding control controls the feed rate of the welding wire such that the tip of the welding wire moves from the position furthest from the base material (i.e., the uppermost end) to the position closest to the base material (i.e., the lowermost end), i.e., the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N While periodically switching the welding current, the welding current is fed into the base material, and at least based on the tip position of the welding wire or the feed speed signal of the welding wire, the welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB The welding control is performed as follows: the forward feed period T is controlled to be such that... P and the reverse feed period T N The combined period is defined as a cycle, and its frequency f is set to 50–150 Hz. The non-suppressed current period T is defined as... IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE )≤0.90, the variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, relative to the distance between the tip and the base material of the welding wire, is set to 14-35%, and the arbitrary current non-suppression period T is set to IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB If )≤0.60, the forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N)≤0.70, and during the non-suppression period of the current T IP During the current suppression period T IB The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +T IB Furthermore, during the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

[0245] According to this structure, in an additional manufacturing method of arc welding in which the forward and reverse feeds of the wire tip are repeated periodically, it is possible to achieve both stable penetration depth and reduced sputtering.

[0246] Various embodiments have been described above with reference to the accompanying drawings, but the present invention is not limited to these examples. Those skilled in the art will understand that various modifications or alterations can be conceived within the scope of the claims, and these also fall within the technical scope of the present invention. Furthermore, the structural elements in the above embodiments can be combined arbitrarily without departing from the spirit of the invention.

[0247] Furthermore, this application is based on Japanese Patent Application No. 2021-152554, filed on September 17, 2021, the contents of which are incorporated herein by reference.

[0248] -Explanation of Figure Markers-

[0249] 50 Welding System

[0250] 100 welding wire

[0251] 110 Welding Robot

[0252] 111 Welding torch

[0253] 120 Welding Control Device

[0254] 140 welding power supply

[0255] 150 controller

[0256] 200 Workpiece (base material)

[0257] f frequency

[0258] Fave average feed rate

[0259] Fw feed rate command signal (feed rate signal)

[0260] I B-AVE During the current suppression period T IB average current

[0261] I P-AVE During the non-suppression period of current T IP average current

[0262] I P1 First welding current setting value

[0263] I P2 Second welding current setting value

[0264] T C Current control range

[0265] T D Declining range

[0266] T IB Current suppression period

[0267] T IP During the non-suppression period of current

[0268] T N During reverse feed

[0269] T P During forward feed

[0270] T U rising range

[0271] Wh wave height.

Claims

1. A welding control method, In gas metal arc welding where welding current is supplied to the welding wire... While controlling the feed speed of the welding wire, the tip of the welding wire moves from the position furthest from the base material (topmost end) to the position closest to the base material (bottommost end), which is the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N During the periodic switching, the material is fed into the parent material. One side is based at least on the tip position of the welding wire or the feed speed signal of the welding wire. The welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB To take control The welding control method is characterized by controlling the welding process as follows: This will make the positive feed period T P and the reverse feed period T N The combined period is defined as one cycle, and its frequency f is set to 50–150 Hz. During the non-suppression period of the current T IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE )≤0.90, The variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, is set relative to the distance between the welding wire tip and the base material to be 14-35%. During any of the current non-suppression periods T IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB )≤0.60, The forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and, During the non-suppression period of the current T IP During the current suppression period T IB The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +T IB )},and, During the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

2. The welding control method according to claim 1, wherein, When the tip of the welding wire is located at the uppermost or lowermost end, the feed speed of the welding wire is set to a predetermined average feed speed value.

3. The welding control method according to claim 1 or 2, wherein, During the non-suppression period of the current T IP By the current suppression period T IB The subsequent upward interval T U During the current suppression period T IB The previous descending range T D and the rising interval T U and the descent interval T D The current control range T outside C constitute, The rising interval T U Relative to the current non-suppression period T IP The decrease range T is below 20%. D Relative to the current non-suppression period T IP It is below 20%.

4. The welding control method according to claim 3, wherein, In the current control range T C It has at least two welding current settings I P1 I P2 , When the uppermost position of the welding wire is set to 0deg, The welding current setting value I P1 The end of the range is set below 20 degrees. The welding current setting value I P2 The end position of the range is set in the range of 135 to 220 degrees.

5. The welding control method according to claim 4, wherein, The welding current setting value I P2 The end of the range is defined as the current control interval T. c At the end, When the welding current setting value I is set P2 When the end position of the range is set to Xdeg, During the current suppression period T IB The end position is set in the range of (X+100) to (X+220) deg.

6. The welding control method according to claim 4, wherein, The welding current setting value I P1 The set current is set to 250-600A. The welding current setting value I P2 The set current is set to 300-650A.

7. The welding control method according to claim 5, wherein, The welding current setting value I P1 The set current is set to 250-600A. The welding current setting value I P2 The set current is set to 300-650A.

8. The welding control method according to claim 4, wherein, In the current control range T C In this context, the external characteristics of the welding power source are set.

9. The welding control method according to claim 5, wherein, In the current control range T C In this context, the external characteristics of the welding power source are set.

10. The welding control method according to claim 6, wherein, In the current control range T C In this context, the external characteristics of the welding power source are set.

11. The welding control method according to claim 7, wherein, In the current control range T C In this context, the external characteristics of the welding power source are set.

12. The welding control method according to claim 1 or 2, wherein, The average volume of the molten droplet detaching from the tip of the welding wire is 1.7–5.0 mm. 3 .

13. A welding control device, In gas metal arc welding where welding current is supplied to the welding wire... While controlling the feed speed of the welding wire, the tip of the welding wire moves from the position furthest from the base material (topmost end) to the position closest to the base material (bottommost end), which is the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N During the periodic switching, the material is fed into the parent material. One side is based at least on the tip position of the welding wire or the feed speed signal of the welding wire. The welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB To take control The welding control device is characterized in that it has the following control function: This will make the positive feed period T P and the reverse feed period T N The combined period is defined as one cycle, and its frequency f is set to 50–150 Hz. During the non-suppression period of the current T IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE )≤0.90, The variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, is set relative to the distance between the welding wire tip and the base material to be 14-35%. During any of the current non-suppression periods T IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB )≤0.60, The forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and, During the non-suppression period of the current T IP During the current suppression period T IB The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +T IB )},and, During the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

14. A welding power source comprising the welding control device of claim 13.

15. A welding system comprising the welding control device of claim 13 or the welding power source of claim 14.

16. A recording medium that records a program, said program causing a welding system computer, which has at least a welding control device, to perform functions. In gas metal arc welding where welding current is supplied to the welding wire... The welding control device controls the feed speed of the welding wire so that the tip of the welding wire moves from the position furthest from the base material (topmost end) to the position closest to the base material (bottommost end), which is the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N During the periodic switching, the material is fed into the parent material. One side is based at least on the tip position of the welding wire or the feed speed signal of the welding wire. The welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB To take control The recording medium is characterized in that, in the aforementioned function, the welding control device is controlled as follows: This will make the positive feed period T P and the reverse feed period T N The combined period is defined as one cycle, and its frequency f is set to 50–150 Hz. During the non-suppression period of the current T IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE )≤0.90, The variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, is set relative to the distance between the welding wire tip and the base material to be 14-35%. During any of the current non-suppression periods T IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB )≤0.60, The forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and, During the non-suppression period of the current T IP During the current suppression period T IB The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +T IB )},and, During the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

17. A welding method that performs gas metal arc welding while simultaneously controlling the welding process. In gas metal arc welding where welding current is supplied to the welding wire... The welding control controls the feed speed of the welding wire so that the tip of the welding wire moves from the position furthest from the base material (topmost end) to the position closest to the base material (bottommost end), which is the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N During the periodic switching, the material is fed into the parent material. One side is based at least on the tip position of the welding wire or the feed speed signal of the welding wire. The welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB To take control The welding method is characterized by performing welding control as follows: This will make the positive feed period T P and the reverse feed period T N The combined period is defined as one cycle, and its frequency f is set to 50–150 Hz. During the non-suppression period of the current T IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I BvAVE )≤0.90, The variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, is set relative to the distance between the welding wire tip and the base material to be 14-35%. During any of the current non-suppression periods T IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB )≤0.60, The forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and, During the non-suppression period of the current T IP During the current suppression period T IB The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +T IB )},and, During the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

18. An additive manufacturing method that performs additive manufacturing simultaneously with welding control. In the aforementioned additional manufacturing process, gas metal arc welding, which involves supplying welding current to the welding wire, is applied. The welding control controls the feed speed of the welding wire so that the tip of the welding wire moves from the position furthest from the base material (topmost end) to the position closest to the base material (bottommost end), which is the forward feed period T. P The reverse feed period T is the period during which the material moves from the lowest point to the highest point. N During the periodic switching, the material is fed into the parent material. One side is based at least on the tip position of the welding wire or the feed speed signal of the welding wire. The welding current is switched to the current non-suppression period T. IP Or during the current suppression period T IB To take control The additional manufacturing method is characterized by performing the welding control as follows: This will make the positive feed period T P and the reverse feed period T N The combined period is defined as one cycle, and its frequency f is set to 50–150 Hz. During the non-suppression period of the current T IP Average current I P-AVE During the current suppression period T IB Average current I B-AVE The relationship is set as 0.65≤I P-AVE / (I P-AVE +I B-AVE )≤0.90, The variation range of the tip position of the welding wire between the uppermost and lowermost ends, i.e., the wave height Wh, is set relative to the distance between the welding wire tip and the base material to be 14-35%. During any of the current non-suppression periods T IP With the current suppression period T that immediately follows IB The relationship is set as 0.30≤T IB / (T IP +T IB )≤0.60, The forward feed period T P During the reverse feed period T N The relationship is set as 0.40≤T N / (T P +T N )≤0.70, and, During the non-suppression period of the current T IP During the current suppression period T IB The forward feed period T P and the reverse feed period T N Let the relationship be {T} N / (T P +T N )}>{T IB / (T IP +T IB )},and, During the non-suppression period of the current T IP Occupy the positive feed period T P More than 2 / 3 of the period.

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