Welding parameter adjustment method, welding parameter setting device, and arc welding system

Abstract

To provide a welding parameter adjustment method that can adjust a welding parameter without requiring shape measurement using cameras or the like in order to suppress undercuts and humping beads.SOLUTION: A welding parameter adjustment method sets a welding table containing a welding parameter and the number of short circuits per unit time as an evaluation index and performs trial welding on a workpiece 200, measures a welding current at this time and calculates an evaluation score related to the evaluation index, estimates a value of the welding parameter on the basis of the evaluation score, repeatedly executes a series of processing from trial welding to estimation of the value of the welding parameter, and changes the value of the welding parameter on the basis of the estimation result of the value of the welding parameter at each starting point, when determining that additional trial welding of the workpiece 200 is no longer required, selects the welding parameter in a case where the evaluation score is highest, and updates the welding table.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a welding parameter adjustment method, a welding parameter setting device, and an arc welding system. [Background technology]

[0002] Conventionally, arc welding is performed on workpieces of various shapes and materials. Welding conditions are set according to the shape and material of the workpiece. In addition, welding parameters for determining the welding current, welding voltage, wire feed amount, etc. are set in accordance with the welding conditions in order to maintain welding quality.

[0003] However, these welding conditions require a wide range of settings, and the number of welding parameters that need to be adjusted is also increasing.

[0004] Therefore, various methods have been proposed for measuring the welding current waveform, welding voltage waveform or other physical quantities during welding and determining the welding parameters based on the measurement results.

[0005] For example, Patent Document 1 proposes a method of learning and optimizing welding parameters based on image data of the appearance of a weld bead and the waveform of an arc sound generated during welding.

[0006] Patent Document 2 proposes a method for pulse arc welding in which the timing of occurrence of a short circuit between the welding wire and the workpiece is detected for each pulse period, an index representing the distribution of the timing of short circuit occurrence per unit time is calculated, and pulse parameters in the welding current waveform are changed based on the index.

[0007] Moreover, Patent Document 3 proposes a method of using a camera to associate welding waveform information with spatter amount and bead shape information, and automatically create optimal welding parameters.

[0008] Patent Document 4 proposes a welding parameter adjustment method capable of adjusting welding parameters regardless of the proficiency of a welding operator. In this welding parameter adjustment method, a welding table and an evaluation index are set, and a workpiece is trial-welded based on the welding table. During the trial welding, a physical quantity related to the welding parameters, for example, the welding current, is measured, and an evaluation score related to the evaluation index is calculated. The value of the welding parameter is estimated based on the evaluation score. A series of processes from trial welding to estimation of the value of the welding parameter is repeatedly performed, and at the start of each round, the value of the welding parameter is changed based on the estimated result of the value of the welding parameter. When it is determined that another trial welding of the workpiece is not necessary, the welding parameter with the highest evaluation score is selected, and the welding table is updated. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 6126174 [Patent Document 2] Patent No. 6100607 [Patent Document 3] JP 2020-157347 A [Patent Document 4] JP 2023-004319 A Summary of the Invention [Problem to be solved by the invention]

[0010] The conventional configurations disclosed in Patent Documents 1 to 3 can simplify the adjustment of some of the welding parameters. Also, the conventional configuration disclosed in Patent Document 4 can adjust the welding parameters simply and reliably, regardless of the skill level of the welding operator.

[0011] Meanwhile, in the production sites of welded products, there is a demand for further improvement in the welding speed in order to shorten the tact time of welding work. In arc welding using a welding wire, when the welding speed is increased, the feeding amount of the welding wire must be increased in order to maintain the deposition amount per unit length. In this case, the heat input for melting the welding wire also increases, so it is necessary to increase the welding current value, the welding voltage value, or both.

[0012] However, when arc welding is performed with these values ​​increased, the droplet transfer from the welding wire may become a spray transfer (welding in this state is also called spray welding). In addition, when welding parameters such as the welding current are adjusted to optimize the amount of spatter, the droplet transfer may also become a spray transfer.

[0013] When the droplet transfer is a spray transfer, undercuts and humping beads are likely to occur, which may lead to a decrease in the strength of the welded portion and a decrease in the weld quality. In particular, when the welding speed is high, the occurrence of undercuts and humping beads tends to increase.

[0014] Normally, information regarding the occurrence and shape of undercuts and humping beads does not appear in the welding current waveform or welding voltage waveform. For this reason, after arc welding, the welded area, i.e., the weld bead, must be measured with a camera or the like, and the shape must be evaluated based on the image.

[0015] However, in this case, a camera must be permanently installed on the arc welding device, or a camera must be attached to the arc welding device every time the welding parameters are adjusted. This requires labor and equipment costs for adjusting the welding parameters. In addition, in order to adjust the welding parameters based on the images measured by the camera, it is necessary to develop a method for adjusting the welding parameters based on the image analysis results, including software. In other words, it is necessary to develop an environment for image analysis and for evaluating the results in association with the welding parameters.

[0016] The present disclosure has been made in consideration of the above points, and an object of the present disclosure is to provide a welding parameter adjustment method, a welding parameter setting device, and an arc welding system that are capable of adjusting welding parameters without requiring shape measurement using a camera or the like in order to suppress undercuts and humping beads. [Means for solving the problem]

[0017] In order to achieve the above object, a welding parameter adjustment method according to the present disclosure is a welding parameter adjustment method for arc welding, comprising: a first step of setting a welding table corresponding to predetermined welding conditions; a second step of setting an evaluation index corresponding to welding quality; a third step of trial welding a workpiece based on the welding table set in the first step; a fourth step of measuring physical quantities related to one or more welding parameters included in the welding table while performing the third step; a fifth step of calculating an evaluation score related to the evaluation index based on the physical quantities measured in the fourth step; a sixth step of determining whether or not to trial weld the workpiece again; and a seventh step of estimating a value of the welding parameter corresponding to the evaluation index based on a value score of the evaluation index, the physical quantity being a welding current or a welding voltage or both, and the evaluation index including at least a number of short circuits per unit time. The method further comprises an eighth step of repeatedly executing a series of processes from the third step to the seventh step, and at the start of each process, changing a value of the welding parameter corresponding to the evaluation index based on a result of estimation in the seventh step, and after determining in the sixth step that a second trial welding is not necessary, selecting the welding parameter with the highest evaluation score and updating the welding table.

[0018] The welding parameter setting device according to the present disclosure comprises at least an input unit to which at least a physical quantity related to one or more welding parameters and measured during arc welding of a workpiece is input, a welding parameter setting unit to set the welding parameters corresponding to predetermined welding conditions, an evaluation score calculation unit to calculate an evaluation score for an evaluation index corresponding to the welding quality of the workpiece based on the physical quantity input to the input unit, and a welding parameter estimation unit to estimate a value of the welding parameter to be adjusted based on the evaluation score, wherein the physical quantity is a welding current or a welding voltage or both, and the evaluation index includes at least the number of short circuits per unit time.

[0019] The arc welding system according to the present disclosure is characterized by including at least an arc welding device for welding a workpiece, and the welding parameter setting device. Effect of the Invention

[0020] According to the present disclosure, welding parameters can be adjusted to suppress undercuts and humping beads without the need for shape measurement using a camera or the like. [Brief description of the drawings]

[0021] [Figure 1] 1 is a schematic configuration diagram of an arc welding system according to a first embodiment. [Diagram 2] FIG. 1 is a schematic diagram of a welding parameter setting device. [Diagram 3] FIG. 4 is a diagram showing an example of a welding current waveform. [Figure 4] 10 is a flowchart showing a procedure for adjusting welding parameters. [Diagram 5] FIG. 4 is a schematic diagram showing an example of a procedure for estimating welding parameters. [Figure 6] 13A and 13B are diagrams illustrating an example of a welding table before and after parameter adjustment. [Figure 7] FIG. 11 is a diagram illustrating an example of a relationship between an evaluation index and an evaluation score. [Figure 8]3A to 3C are diagrams showing the surface state of a workpiece, a welding current waveform, and a welding voltage waveform during spray welding. [Figure 9] 4A to 4C are diagrams showing the surface state of a workpiece, a welding current waveform, and a welding voltage waveform during short-circuit welding. [Figure 10] 1 is a photograph showing a weld bead, an undercut, and a humping bead formed on a workpiece. [Figure 11] FIG. 11 is a diagram showing an example of a relationship between a focus point, an evaluation index, and an evaluation score of welding quality according to the second embodiment. [Figure 12] FIG. 4 is a diagram showing an example of a welding current waveform and a welding voltage waveform in a normal state. [Figure 13] FIG. 4 is a diagram showing an example of a welding current waveform and a welding voltage waveform when a short circuit occurs during a peak section. [Figure 14] 11 is a flowchart of a procedure for adjusting welding parameters according to a third embodiment. [Figure 15] 1 is a flowchart of a procedure for adjusting welding parameters related to the appearance of a weld bead. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present disclosure, its application, or its uses.

[0023] (Embodiment 1) [Arc welding system configuration] 1 is a schematic diagram of an arc welding system according to the present embodiment. The arc welding system 300 includes an arc welding device 20 and a welding parameter setting device 100.

[0024] Arc welding device 20 performs welding by generating an arc 80 between welding wire 50, which is a consumable electrode, and workpiece 200, which is an object to be welded. Note that welding wire 50 is held by torch 30, and as torch 30 moves at a predetermined speed, the tip of welding wire 50 also moves at the same speed along a predetermined welding section. Note that torch 30 has a supply port (not shown) for shielding gas that is sprayed onto workpiece 200 during welding.

[0025] Arc welding apparatus 20 has a main transformer 2, a primary side rectifier 3, a switching unit 4, a DCL (reactor) 5, a secondary side rectifier 6, a welding current detector 7, a welding voltage detector 8, a control switch unit 9, an output controller 10, a wire feed speed controller 13, and a torch 30. Arc welding apparatus 20 also has a robot controller (not shown) that controls the operation of a robot 60 that holds torch 30. Arc welding apparatus 20 may also include a wire feeder 40.

[0026] The output control unit 10 has a short circuit welding control unit 11 and a pulse welding control unit 12. The wire feed speed control unit 13 has a wire feed speed detection unit 14 and a wire feed speed calculation unit 15. The primary side rectification unit 3 rectifies the input voltage input from an input power source (three-phase AC power source) 1 external to the arc welding apparatus 20. The switching unit 4 controls the output of the primary side rectification unit 3 to an output suitable for welding. The main transformer 2 converts the output of the switching unit 4 to an output suitable for welding. The secondary side rectification unit 6 rectifies the output of the main transformer 2. The DCL (reactor) 5 smoothes the output of the secondary side rectification unit 6 to a current suitable for welding.

[0027] The welding current detection unit 7 detects the welding current. The welding voltage detection unit 8 detects the welding voltage. In the following description, the welding current and / or welding voltage measured during welding may be referred to as physical quantities.

[0028] The control switching unit 9 is a switching unit that outputs to the output control unit 10 the timing for switching from short circuit welding control to pulse welding control.

[0029] Output control unit 10 outputs a control signal to switching unit 4 to control the welding output. Short circuit welding control unit 11 controls short circuit welding when control switching unit 9 commands short circuit welding. Pulse welding control unit 12 controls pulse welding when control switching unit 9 commands pulse welding. As will be described later, welding parameters set by welding parameter setting device 100 are input to output control unit 10, and short circuit welding and pulse welding are controlled based on these parameters.

[0030] Wire feed speed control unit 13 controls wire feeder 40 to control the feed speed of welding wire 50. Wire feed speed detection unit 14 detects the wire feed speed. Wire feed speed calculation unit 15 calculates the feed amount of welding wire 50 based on a signal from wire feed speed detection unit 14. Also, it calculates an integrated amount of the feed amount of welding wire 50. Also, wire feed speed calculation unit 15 compares a command value and a detected value of the wire feed speed to find a difference, and performs feedback control so as to match the actual wire feed speed to the command value based on the integrated amount of the difference.

[0031] A wire feeder 40 and a welding parameter setting device 100 are connected to the arc welding apparatus 20. The welding parameter setting device 100 sets various welding parameters for predetermined welding conditions in the arc welding apparatus 20. The configuration of the welding parameter setting device 100 and the functions of each part will be described in detail later.

[0032] It is preferable that arc welding apparatus 20 and welding parameter setting device 100 each have a communication interface unit (not shown). Data is exchanged between arc welding apparatus 20 and welding parameter setting device 100 via each communication interface unit. In this case, arc welding apparatus 20 and welding parameter setting device 100 may be connected by Ethernet (registered trademark), an analog cable, a serial cable, or the like.

[0033] Robot 60 is a known multi-joint axis robot that moves torch 30 so that the tip of welding wire 50 held by torch 30 moves at a set welding speed along a predetermined weld line (not shown) on workpiece 200.

[0034] The above-mentioned control switching unit 9, output control unit 10, and wire feed speed calculation unit 15 may each be incorporated as a functional block in welding parameter setting device 100 (see, for example, FIG. 2).

[0035] Furthermore, welding speed calculation unit 16 (see FIG. 2) may be incorporated in welding parameter setting device 100. The rotation amount and rotation speed of each joint shaft incorporated in robot 60 are measured by an encoder (not shown), and based on the measurement results, welding speed calculation unit 16 calculates the moving speed of the tip of welding wire 50, that is, the welding speed.

[0036] When a torch SW (switch) (not shown) is turned ON, the welding output of the arc welding device 20 is supplied to the welding wire 50 via the power cable 70 and the welding tip 31. The power cable 70 is connected to both the welding tip 31 and the workpiece 200. Then, the welding output of the arc welding device 20 generates an arc 80 between the welding wire 50 and the workpiece 200, thereby performing welding.

[0037] [Welding parameter setting device configuration] FIG. 2 shows a schematic configuration diagram of a welding parameter setting device, and FIG. 3 shows an example of a welding current waveform.

[0038] As described later, welding parameter setting device 100 has a plurality of functional blocks. Typically, welding parameter setting device 100 is configured with a known computer, and a plurality of functional blocks in welding parameter setting device 100 are configured and operated by executing software implemented on a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit).

[0039] In this specification, the term "welding conditions" refers to evaluation items when welding the workpiece 200. For example, the welding conditions include the welding method (MIG / MAG / TIG, etc.) and the material of the workpiece 200 (mild steel / aluminum, etc.). The welding conditions also include the diameter (wire diameter) of the welding wire 50 and the types of welding control conditions (welding current / welding voltage / wire feed amount / welding speed, etc.).

[0040] On the other hand, "welding parameters" refer to specific items in the welding control conditions. For example, when performing pulse welding, the pulse width and rise / fall times of the welding current are both welding parameters, as shown in Figure 3. In addition, the peak current value and base current value of the welding current are also welding parameters.

[0041] 2, welding parameter setting device 100 has a number of functional blocks as shown below. Welding parameter setting device 100 has an input unit 101, an output unit 102, a memory unit 103, and a display unit 104. Welding parameter setting device 100 has a welding parameter setting unit 105, an evaluation score calculation unit 106, and a welding parameter estimation unit 107. Welding parameter setting device 100 further has an adjustment parameter selection unit 108, an evaluation function setting unit 109, a number of trials setting unit 110, and a welding table setting unit 111.

[0042] 2, the functional blocks enclosed by dashed lines may be omitted or incorporated in other devices. For example, the output control unit 10 is incorporated in the arc welding device 20 as described above. In this case, the output control unit 10 is not set in the welding parameter setting device 100.

[0043] The welding current detected by the welding current detection unit 7 of the arc welding device 20, the welding voltage detected by the welding voltage detection unit 8, or both are input to the input unit 101. In this embodiment, the welding current waveform will be described as an example.

[0044] Output unit 102 outputs a welding table (see, for example, FIG. 6) including the final changed welding parameters to output control unit 10 of arc welding apparatus 20. Note that, as indicated by the dashed line in FIG. 2, when output control unit 10 is provided inside welding parameter setting device 100, output unit 102 may be omitted.

[0045] The memory unit 103 stores the welding current waveform, or the welding voltage waveform, or both, input to the input unit 101. The memory unit 103 also stores the above-mentioned welding table. The welding table is data in which the details of the welding conditions and the items and values ​​of a plurality of welding parameters associated with the welding conditions (hereinafter, sometimes referred to as a welding parameter group) are compiled in a tabular format (see FIG. 6). Note that each piece of data may also be compiled in a text format. The memory unit 103 also stores an evaluation score and an evaluation function, which will be described later. The memory unit 103 temporarily stores estimated values ​​of the welding parameters calculated one or more times until the optimal values ​​are obtained.

[0046] The display unit 104 is configured with a known liquid crystal display, an organic EL display, etc. The display unit 104 displays the evaluation score calculated by the evaluation score calculation unit 106. In this case, the display unit 104 may display a result of comparison with a corresponding evaluation score when the welding result is evaluated using a standard table described later.

[0047] Welding parameter setting unit 105 sets welding parameters, which are specific items used to control the welding output, based on given welding conditions, or based on the welding conditions and the welding current, welding voltage, or both detected by arc welding apparatus 20. Examples of the welding parameters are as described above.

[0048] The evaluation score calculation unit 106 calculates an evaluation score for the evaluation index based on the evaluation index corresponding to the welding current, the welding voltage, or both. The evaluation index is an event that indicates welding quality that can be detected / measured from a physical quantity. Specific examples of the evaluation index will be described later. More specifically, the evaluation index is evaluated using an evaluation function set in the evaluation function setting unit 109 to calculate the evaluation score. The evaluation function is a function that calculates the evaluation score based on the quantified evaluation index. Specific examples of the evaluation function will be described later.

[0049] Welding parameter estimation unit 107 estimates the value of the welding parameter corresponding to the evaluation index based on the evaluation score calculated by evaluation score calculation unit 106. In this case, the welding parameter can be estimated by various methods, which will be described later.

[0050] The adjustment parameter selection unit 108 selects the welding parameters to be adjusted based on the welding conditions of the workpiece 200. There are various welding conditions related to the adjustment of the welding parameters, including indirect conditions.

[0051] In addition, if the change items of the welding conditions are fixed to a certain extent, the welding conditions may be displayed on display unit 104 and the change contents of the welding conditions may be selected in a pull-down format when adjusting the welding parameters. In this case, by selecting and confirming the change contents of the welding conditions, adjustment parameter selection unit 108 may automatically select the welding parameters to be adjusted.

[0052] The evaluation function setting unit 109 sets an evaluation function for calculating the evaluation score. When it is necessary to prepare a plurality of evaluation functions according to the welding conditions and the welding parameters to be adjusted, the evaluation functions are stored in the storage unit 103, and the evaluation function setting unit 109 selects a corresponding evaluation function.

[0053] Trial count setting unit 110 sets the number of trial welding and evaluations required to select optimal values ​​for the welding parameters to be adjusted.

[0054] Welding table setting unit 111 sets a welding table corresponding to given welding conditions when welding workpiece 200. Usually, for welding conditions that have been used in the past, a welding table corresponding to the welding conditions is stored in storage unit 103 as a standard table. In the standard table, welding conditions that have been used in the past and a group of welding parameters (hereinafter, sometimes referred to as standard parameters) associated therewith are summarized in a tabular form. Therefore, when changing welding conditions that have been used in the past, welding table setting unit 111 calls up the standard table from storage unit 103. For welding parameters to be adjusted from the group of standard parameters, optimal parameters are selected by repeating trial welding and evaluation, as will be described later.

[0055] Welding parameter readjustment unit 112 adjusts the values ​​of the welding parameters based on the estimation results from welding parameter estimation unit 107. However, this function may be incorporated into another functional block. For example, the function of welding parameter readjustment unit 112 may be incorporated into welding parameter setting unit 105. In that case, welding parameter readjustment unit 112 may be omitted.

[0056] The welding table is called up and the welding parameters to be set or adjusted are selected by the welding operator via input unit 101, and the selected contents are confirmed by welding table setting unit 111 and adjustment parameter selection unit 108 in response to an input signal from input unit 101. Similarly, the evaluation function and the number of trials are also set by the welding operator via input unit 101, and the setting contents are confirmed by evaluation function setting unit 109 and number of trials setting unit 110 in response to an input signal from input unit 101.

[0057] Display unit 104 may be a touch panel display. In this case, the welding operator inputs data to welding parameter setting device 100 via display unit 104.

[0058] Furthermore, welding parameter setting device 100 may be installed in a single housing together with arc welding device 20 so as to share the respective control units and arithmetic units of arc welding device 20 .

[0059] [Welding parameter adjustment method] Fig. 4 shows a flow chart of the procedure for adjusting the welding parameters. In the example shown in Fig. 4, the peak current value and peak width shown in Fig. 3 are selected as the welding parameters. However, it goes without saying that the number and types of welding parameters to be adjusted are appropriately changed depending on the modification of the welding conditions and the items and contents that are important in the welding quality. The above-mentioned two welding parameters are related to the occurrence of undercut 211 (see Fig. 10) and humping bead 212 (see Fig. 10) in workpiece 200 after welding.

[0060] When adjusting the welding parameters according to the modification of the welding conditions or the welding quality, the following procedure is performed.

[0061] First, the arc welding device 20 is initialized. A welding table is set (step S1). Specifically, the welding conditions are set according to the shape, size, material, etc. of the workpiece 200. According to the set welding conditions, the welding parameter setting unit 105 sets welding parameters based on the set welding conditions. If the welding conditions have been processed in the past, the welding table setting unit 111 calls a standard table from the storage unit 103 and sets it as the welding table. The standard table is set in the output control unit 10. If the welding conditions have not been processed in the past, the welding table setting unit 111 calls a welding table that is close to the welding conditions and has been processed in the past from the storage unit 103 and sets it as the welding table to be used for the trial welding. The welding parameter setting unit 105 may modify the welding parameters in the welding table.

[0062] Next, the adjustment parameter selection unit 108 selects the welding parameters to be adjusted based on the welding conditions of the workpiece 200 (step S2). For example, when the welding conditions in the standard table are changed, the adjustment parameter selection unit 108 selects the welding parameters to be adjusted according to the changes. In this embodiment, the peak current value and the peak width are selected.

[0063] In step S2, candidates for the welding parameters to be adjusted may be selected according to the changes in the welding conditions. For example, candidates for the changes are automatically displayed on display unit 104 via input unit 101, and the welding operator selects the corresponding changes from the candidates. When the changes are confirmed, candidates for the welding parameters associated with the changes are automatically displayed on display unit 104, and the welding operator selects the corresponding welding parameters from the candidates. Also, candidates for the welding parameters to be adjusted may be selected according to the required specifications for welding quality. The selection procedure in this case is similar to that described above.

[0064] Evaluation score calculation unit 106 selects an evaluation index corresponding to the welding parameters to be adjusted. Furthermore, evaluation function setting unit 109 selects the above-mentioned evaluation function (step S3). The evaluation index is selected in accordance with the required welding quality, and in this embodiment, the number A of short circuits per second during the welding period is the evaluation index (index 1) (see FIG. 7). Note that this number A of short circuits corresponds to the frequency of short circuit occurrence during the welding period, that is, the short circuit frequency.

[0065] Furthermore, trial count setting unit 110 sets the number of trials for changing and updating the values ​​of the welding parameters selected in step S2, and also sets a method for estimating the welding parameters, which will be described later (step S4).

[0066] Next, based on the welding table set in step S1, trial welding is performed on workpiece 200 (step S5). During execution of step S5, welding current detection unit 7 detects the welding current. Also, welding voltage detection unit 8 detects the welding voltage. Also, wire feed speed detection unit 14 detects the feed speed of welding wire 50. These measured values ​​are acquired by welding parameter setting device 100 via input unit 101 (step S6).

[0067] Next, the result of the trial welding is evaluated (step S7). The evaluation items are determined according to the required welding quality. In this embodiment, attention is focused on the appearance of a weld bead 210 (see, for example, FIG. 10) formed by welding, and specifically, the presence or absence of an undercut 211 (see FIG. 10) or a humping bead 212 (see FIG. 10) is set as an evaluation item (see FIG. 7). The evaluation result in step S7 is used in the processing of step S9 described later.

[0068] Next, based on the evaluation result in step S7, the evaluation score calculation unit 106 calculates an evaluation score corresponding to the welding parameter selected in step S2 (step S8). Specifically, the evaluation result in step S7 is quantified, and the quantitative data is input to the evaluation function selected in step S3 to obtain the evaluation score. Note that step S8 may be performed before execution of step S10.

[0069] Furthermore, it is determined whether or not to perform trial welding again (step S9). The determination in step S9 is made by the welding operator who performed the trial welding or by an evaluator who evaluated the welding results. If the determination result in step S9 is positive, that is, it is determined that trial welding of the workpiece 200 needs to be performed again, the process proceeds to step S10. On the other hand, if the determination result in step S9 is negative, that is, it is determined that trial welding of the workpiece 200 does not need to be performed any more, the process proceeds to step S12.

[0070] In step S10, welding parameter estimation unit 107 estimates values ​​of welding parameters to be applied in the next trial. These welding parameters are the parameters to be adjusted selected in step S2. The values ​​of the welding parameters are estimated according to the estimation method set in step S4. The evaluation function selected in step S3 and the evaluation score calculated in step S8 are used to estimate the values ​​of the welding parameters.

[0071] Various estimation methods can be applied. For example, random search, Bayesian optimization, machine learning using neural networks, etc. can be applied. Random search is a method of randomly combining candidate values ​​for the next numerical value to be used. Bayesian optimization is a type of optimization algorithm that searches for the next value to be searched.

[0072] The values ​​of the welding parameters are changed to the estimated values ​​estimated in step S10 (step S11). Then, the process returns to step S5, and trial welding of the workpiece 200 is performed again. The welding parameters or welding table after the values ​​have been changed are temporarily stored in the storage unit 103. At this time, the values ​​of the changed welding parameters are associated with the above-mentioned evaluation scores and stored in the storage unit 103.

[0073] A series of processes from steps S5 to S8 and steps S10 and S11 are repeatedly executed until the determination result of step S9 becomes negative. In addition, every time step S10 is executed, the welding parameters or welding table after the values ​​are changed are temporarily stored in storage unit 103.

[0074] When the determination result in step S9 becomes negative and the process proceeds to step S12, welding parameter setting unit 105 selects the value with the highest evaluation score from the values ​​of the multiple welding parameters temporarily stored in storage unit 103 (step S12), and further updates the value of the welding parameter to the value selected in step S12 (step S13).

[0075] By executing the procedure described above, welding parameters are selected according to the changes in welding conditions and the required welding quality, and the welding table is updated.

[0076] In this specification, "changing a value" refers to changing a value to a value different from the previous value. Specifically, the values ​​of the welding parameters before and after the change will be different from each other. Furthermore, "updating a value" refers to changing the previous value to a value of a new version. Specifically, the values ​​of the welding parameters before and after the update may be the same or different. The update information is associated with the updated welding parameter values, for example, as version information.

[0077] As shown in this embodiment, by repeatedly estimating the welding parameters after determining whether or not trial welding is required, it is possible to estimate the optimal values ​​of the welding parameters in a smaller number of times.

[0078] An example of the procedure for estimating welding parameters is shown in Fig. 5. Starting from the pair of peak current and peak width indicated by the star at the bottom left, trial welding and evaluation of the welding results are sequentially repeated, and a pair of peak current and peak width is estimated each time.

[0079] The appropriate range shown in Fig. 5 is, for example, a range in which the number of occurrences of undercuts 211 and humping beads 212 or the occurrence length is equal to or less than the level that satisfies the required specifications. As shown in this embodiment, a set of peak current value and peak width corresponding to the appropriate range can be estimated by the fourth and fifth estimations. However, at this point, it is not known whether this is the optimal value or not. In addition, if trial welding, evaluation of the welding results, and estimation of welding parameters are repeated to approach the optimal value, more man-hours are required, and there is a risk of reducing the efficiency of the adjustment work.

[0080] Therefore, by repeatedly estimating the welding parameters until it is determined that further trial welding is unnecessary, and selecting a final value based on the evaluation score from the multiple values ​​obtained, it is possible to estimate the optimal value of the welding parameters in fewer iterations.

[0081] As shown in Fig. 6, the welding table before adjustment is updated by incorporating the updated welding parameters. In this case, the peak current value Ip1 and peak width Tp1 before adjustment are updated to the peak current value Ip2 and peak width Tp2, respectively, after adjustment.

[0082] The adjusted welding table is stored in the storage unit 103. The welding table before the adjustment may be stored as it is in the storage unit 103. When the changes in the welding conditions are different from the example shown in FIG. 4, the options for which welding table to use as the standard table can be expanded.

[0083] [Relationship between the occurrence of undercut and humping bead and welding method] 7 is a diagram showing an example of the relationship between the evaluation index and the evaluation score, and as described above, the number of short circuits A per second during the welding period is set as index 1. In this embodiment, the evaluation score is set to 0.1 when A≦0.25, and 0.9 when A>0.25. However, this is not particularly limited, and the value of the evaluation score, the classification of the evaluation score regarding the value of A, the fluctuation range of the evaluation score, etc. can be appropriately changed according to the number of short circuits A per second and the actual occurrence status of the undercut 211 and the humping bead 212.

[0084] Here, the causes of the undercut 211 and the humping bead 212 occurring in arc welding will be described.

[0085] Fig. 8 is a diagram showing the surface condition of the workpiece, the welding current waveform, and the welding voltage waveform during spray welding, and Fig. 9 is a diagram showing the surface condition of the workpiece, the welding current waveform, and the welding voltage waveform during short-circuit welding. Fig. 10 is a photograph showing the weld bead, undercut, and humping bead formed on the workpiece.

[0086] In Fig. 8 and Fig. 9, the top diagram shows the surface state of the workpiece during welding, the center diagram shows the welding current waveform, and the bottom diagram shows the welding voltage waveform. Note that the scale of the vertical and horizontal axes of the graph in Fig. 8 is different from that of the vertical and horizontal axes of the graph in Fig. 9. In Fig. 9, the position of the welding wire 50 in Fig. 8 is indicated by a dashed line.

[0087] In the case of spray welding, the welding voltage is higher than in the case of short circuit welding, so that the arc length La1 of the arc 80 shown in FIG 8 is longer than the arc length La2 of the arc 80 shown in FIG 9.

[0088] Generally, the longer the arc length, the larger the lateral spread of the arc 80. Also, the pressure of the arc 80 tends to push the molten pool 201 formed in the workpiece 200 downward toward the inside of the workpiece 200, which tends to cause a dent.

[0089] However, as described above, there is a strong demand for increasing the welding speed in general arc welding. When the welding speed is increased, the deposition amount per unit time decreases, so the wire feed amount must be increased at the same time. However, in reality, it is difficult to ensure a wire feed amount sufficient to compensate for the insufficient deposition amount.

[0090] In this case, the molten pool 201 solidifies while being pressed down, so that an undercut 211 occurs on the periphery of the molten pool 201, i.e., on the periphery of the weld bead 210, as shown in Figure 10. Furthermore, if the welding speed is further increased under conditions that cause the undercut 211 to occur, a humping bead 212 occurs (see Figure 10).

[0091] In view of the above, in order to suppress the occurrence of undercut 211 and humping bead 212, it is preferable to short-circuit welding wire 50 and workpiece 200 at an appropriate cycle during the welding period to reduce the welding voltage (see FIG. 9). Therefore, if the occurrence or non-occurrence of undercut 211 and humping bead 212 is defined as the welding quality, in this embodiment, the evaluation index (index 1) corresponding to the welding quality is the number of short-circuits A per second during the welding period. Note that the number of short-circuits per unit time during the welding period may be selected as index 1. In this case, the unit time is set appropriately depending on the length of the welding period, the repetition cycle of the pulse current, etc.

[0092] [Effects, etc.] As described above, the welding parameter adjustment method according to this embodiment includes at least a first step (step S1) of setting a welding table corresponding to predetermined welding conditions, a second step (step S3) of setting an evaluation index corresponding to welding quality, and a third step (step S5) of welding a workpiece based on the welding table set in the first step.

[0093] The welding parameter adjustment method includes a fourth step (step S6) of measuring a physical quantity related to one or more welding parameters included in the welding table during execution of the third step, and a fifth step (step S8) of calculating an evaluation score for the evaluation index based on the physical quantity measured in the fourth step. As described above, the physical quantity is the welding current or the welding voltage, or both.

[0094] In this embodiment, the occurrence or nonoccurrence of undercut 211 and humping bead 212 is regarded as the welding quality, and the evaluation index (index 1) is the number of short circuits A per second during the welding period. As described above, index 1 may be the number of short circuits per unit time during the welding period.

[0095] The welding parameter adjustment method also includes a sixth step (step S9) of determining whether or not to perform trial welding on the workpiece 200 again, and a seventh step (step S10) of estimating values ​​of the welding parameters corresponding to the evaluation index based on the evaluation score.

[0096] A series of processes from the third step to the seventh step are repeated a predetermined number of times, and at the start of each cycle, the value of the welding parameter corresponding to the evaluation index is changed based on the estimation result in the seventh step (step S11).

[0097] The method further includes an eighth step (steps S12 and S13) of selecting the welding parameters with the highest evaluation score after it is determined in the sixth step that another trial welding is not necessary, and updating the welding parameters.

[0098] According to this embodiment, it is possible to evaluate the occurrence of undercut 211 and humping bead 212 and further suppress their occurrence, regardless of the skill level of the welding operator and without the need for a measuring unit such as a camera that directly measures the shape of weld bead 210. This makes it possible to maintain weld quality even when the welding conditions are changed.

[0099] According to the present embodiment, the welding parameters can be adjusted simply and reliably, regardless of the skill level of the welding operator. Furthermore, an increase in the number of steps required for adjusting the welding parameters can be suppressed.

[0100] In carrying out the fifth step, it is preferable to select a predetermined evaluation function and evaluate the evaluation index with the evaluation function to obtain an evaluation score.

[0101] In this way, the welding parameter values ​​can be objectively evaluated using the evaluation score. It becomes easy to compare the welding parameter values ​​estimated in multiple trials. In addition, it is easy to select the optimal value from among the multiple estimated welding parameter values.

[0102] When repeating a series of processes, it is preferable that in any one of the first steps, a standard table prepared in advance is set in accordance with the welding conditions, and in the third step, the workpiece 200 is trial-welded based on the standard table.

[0103] By performing trial welding using a standard table prepared in advance and obtaining an evaluation score for the result, the amount of adjustment of the welding parameter values ​​can be reduced, which prevents a significant increase in the number of trials required to select optimal parameters, and improves the efficiency of adjustment work. In the example shown in Fig. 4, trial welding using the standard table and evaluation of the result are performed first, but this is not particularly limited. When performing trial welding multiple times, trial welding using the standard table and evaluation of the result, and further calculation of the evaluation score may be performed.

[0104] It is also preferable to display the evaluation score in comparison with the evaluation score when the standard table is used.

[0105] In this way, the welding operator can easily check whether the adjustment of the welding parameters has been performed appropriately.

[0106] The welding parameter setting device 100 according to this embodiment includes at least an input unit 101 to which the above-mentioned physical quantities related to one or more welding parameters and measured during arc welding of a workpiece 200 are input, and a welding parameter setting unit 105 to set welding parameters corresponding to predetermined welding conditions.

[0107] In addition, welding parameter setting device 100 is equipped with an evaluation score calculation unit 106 that calculates an evaluation score for an evaluation index corresponding to the welding quality of workpiece 200 based on the above-mentioned physical quantities, and a welding parameter estimation unit 107 that estimates values ​​of welding parameters to be adjusted based on the evaluation score.

[0108] As described above, the evaluation items are the occurrence or nonoccurrence of undercut 211 and humping bead 212, and the evaluation index (index 1) is the number of short circuits A per second during the welding period. Note that, as described above, index 1 may be the number of short circuits per unit time during the welding period.

[0109] By configuring welding parameter setting device 100 in this manner, the occurrence of undercut 211 and humping bead 212 can be evaluated regardless of the skill level of the welding operator and without the need for a measuring unit such as a camera that directly measures the shape of weld bead 210. Furthermore, the occurrence of these can be suppressed. This makes it possible to maintain welding quality even when the welding conditions are changed. Furthermore, it is possible to suppress an increase in the number of steps required for adjusting the welding parameters.

[0110] It is preferable that welding parameter setting device 100 further includes a memory unit 103 that stores at least one or more welding parameters corresponding to the welding conditions, the above-mentioned physical quantities input to input unit 101, and the evaluation score calculated by evaluation score calculation unit 106, and a display unit 104 that displays at least the evaluation score.

[0111] In this manner, the welding parameters can be adjusted efficiently. Storage unit 103 may be provided outside welding parameter setting device 100. Storage unit 103 may be configured to be able to exchange data with welding parameter setting device 100, and may be provided in an external server, for example.

[0112] Welding parameter setting device 100 preferably further includes a welding table setting unit 111 that sets a welding table, which is a group of welding parameters corresponding to welding conditions, and an adjustment parameter selection unit 108 that selects the welding parameters to be adjusted. Also, it is preferable that welding parameter setting device 100 further includes an evaluation function setting unit 109 that sets an evaluation function for calculating an evaluation score, and a trial number setting unit that sets the number of trial welding operations of workpiece 200 required to estimate the values ​​of the welding parameters.

[0113] In this way, the welding parameters can be adjusted simply and reliably.

[0114] The arc welding system 300 according to this embodiment includes at least an arc welding device 20 for welding a workpiece 200 and a welding parameter setting device 100 .

[0115] By configuring the arc welding system 300 in this way, the welding parameters can be easily and appropriately adjusted in response to changes in the welding conditions and the required specifications for the welding quality, making it possible to perform arc welding while maintaining high quality on the workpieces 200 having various shapes and materials.

[0116] (Embodiment 2) In the first embodiment, the peak current value and the peak width in pulse welding are the welding parameters to be adjusted. However, the present invention is not limited to this, and candidates for the welding parameters to be adjusted may be selected according to changes in the welding conditions. Furthermore, candidates for the welding parameters to be adjusted may be selected according to the required specifications for the welding quality.

[0117] In this way, even a welding operator who does not have know-how regarding adjustment of welding parameters can easily and appropriately adjust the welding parameters according to the situation. Also, by selecting candidates for the welding parameters to be adjusted according to the specifications required for the welding quality, the welding parameters can be appropriately adjusted and the welding quality can be maintained.

[0118] In this case, the selected evaluation index and evaluation function are also changed depending on the welding parameters to be adjusted.

[0119] Furthermore, the evaluation items of the welding quality include not only the aesthetic appearance of the weld bead 210, including the presence or absence of undercut 211 and humping bead 212, but also various other items. For example, the amount of spatter during arc welding can be quantified based on a predetermined evaluation index, and an evaluation score can be calculated.

[0120] Fig. 11 shows an example of the relationship between the focus of welding quality, the evaluation index, and the evaluation score according to this embodiment. In the example shown in Fig. 11, the appearance of weld bead 210 and the amount of spatter are selected as the focus of welding quality. Also, index 1 described above is selected as the evaluation index related to the appearance of weld bead 210. Meanwhile, the ratio x (index 2) of the number of short circuits at the peak to the number of peaks, and the average current value y (index 3) during a short circuit are selected as evaluation indexes related to the amount of spatter. The amount of spatter is also an evaluation item for welding quality. Index 2 and index 3 will be further explained.

[0121] FIG. 12 shows an example of a welding current waveform and a welding voltage waveform in a normal state, and FIG. 13 shows an example of a welding current waveform and a welding voltage waveform when a short circuit occurs during the peak section.

[0122] As shown in FIG. 12, if no short circuit occurs during the peak section, the ratio x is zero. In this case, the evaluation score for index 2 is 0.5, as shown in FIG. 11. Also, when the welding voltage drops to Vs, a short circuit is detected. In the example shown in FIG. 12, a short circuit is detected after each of the two peak sections ends. Therefore, the average current value y mentioned above is (Ib+Ib) / 2=Ib. Since Ib shown in FIG. 12 is 90 A, the evaluation score for index 3 is 0.4, as shown in FIG. 11.

[0123] On the other hand, as shown in FIG. 13, if one short circuit occurs during one of the two peak intervals, the ratio x is 0.5. In this case, the evaluation score for index 2 is 0.2, as shown in FIG. 11. In the example shown in FIG. 13, a short circuit is detected during the first peak interval, and then after the second peak interval ends. Therefore, the average current value y is (Ip+Ib) / 2. Since Ip and Ib shown in FIG. 12 are 350 A and 90 A, respectively, the average current value y is 220 A, and the evaluation score for index 3 is 0.1, as shown in FIG. 11.

[0124] 11, the evaluation score for the spatter amount in the evaluation function is set to the sum of the evaluation score for index 2 and the evaluation score for index 3. Therefore, in the example shown in FIG. 12, the evaluation score is 0.9, and in the example shown in FIG. 13, the evaluation score is 0.3. That is, the example shown in FIG. 12 has a higher evaluation score than the example shown in FIG. 13. If a short circuit occurs during a peak section where the current value is high, the vibration of the molten pool formed on the workpiece 200 becomes large, spatter is more likely to occur, and the amount of spatter increases.

[0125] According to this embodiment, different evaluation indices are established for different welding quality focus points, and evaluation scores are calculated based on these evaluation indices. Furthermore, optimal welding parameter values ​​are estimated based on the calculated evaluation scores. This makes it possible to set welding parameters to satisfy each of the required specifications even when there are multiple types of welding quality. In addition, different evaluation functions are selected depending on which of the amount of spatter and the appearance of the weld bead 210 is given more importance and how.

[0126] When it is desired to equally reflect both the amount of spatter and the appearance of weld bead 210 in the evaluation score, for example, evaluation function A shown in Fig. 11 is selected. That is, the evaluation scores for indexes 1, 2, and 3 are added together to obtain the final evaluation score.

[0127] On the other hand, if you want to adjust how the amount of spatter and the appearance of weld bead 210 are reflected in the evaluation score, for example, select evaluation function B shown in Figure 11 and change the values ​​of weighting coefficients α, β, and γ in evaluation function B as appropriate.

[0128] Moreover, evaluation function setting unit 109 may set an appropriate evaluation function by inputting what is important regarding welding quality into input unit 101. For example, as described above, when display unit 104 is a touch panel that also serves as input unit 101, the required specifications for welding quality are displayed on display unit 104.

[0129] In this embodiment, the amount of spatter is taken as an evaluation item of the welding quality other than the occurrence or absence of undercut 211 and humping bead 212, but the present invention is not limited to this. For example, if the width of weld bead 210 varies more than necessary, the aesthetic appearance is also impaired. In such a case, the number of times z that short circuit welding and spray welding are mixed is used as an evaluation index, and an evaluation score is set according to the value of z. Specifically, the peak current value, peak width, base current value, etc. of the welding current are adjusted so that the value of z becomes smaller.

[0130] (Embodiment 3) In the second embodiment, when there are multiple types of welding quality points of interest, an evaluation index is set for each, and an evaluation score is calculated based on these evaluation indexes. Furthermore, the calculated evaluation scores are added as they are, or are multiplied by appropriate weighting coefficients and then added to derive a final evaluation score. Furthermore, the optimal welding parameter values ​​are estimated based on the derived final evaluation score.

[0131] However, adjusting the welding parameters and setting the weighting coefficients according to the flowchart shown in FIG. 4 may result in a significant increase in the number of trials. Therefore, when there are multiple types of welding quality to focus on, evaluation indexes corresponding to some of the welding qualities are set, and the welding parameters corresponding to those evaluation indexes are adjusted first. After that, evaluation indexes corresponding to the remaining welding qualities are set, and the welding parameters corresponding to those evaluation indexes are adjusted. If the welding parameters overlap between the former and latter, the values ​​determined in the latter adjustment work are used in the actual welding. A specific explanation is given below.

[0132] FIG. 14 is a flowchart of the procedure for adjusting the welding parameters according to this embodiment, and FIG. 15 is a flowchart of the procedure for adjusting the welding parameters relating to the appearance of the weld bead.

[0133] The flowchart shown in FIG. 15 is the same as the flowchart shown in FIG. 4, and the welding parameters adjusted in this operation are the peak current value and peak width of the pulse current.

[0134] On the other hand, steps S21 to S33 shown in Fig. 14 are similar to steps S1 to S13 shown in Fig. 4, respectively. Therefore, detailed description will be omitted. However, in the adjustment work shown in Fig. 14, welding parameters related to suppression of the amount of spatter are adjusted.

[0135] As shown in FIG. 14, between steps S21 and S22 (point A1) or after step S33 (point A2), the peak current value and peak width of the pulse current are updated to values ​​set by the adjustment work shown in FIG. 15.

[0136] When the peak current value and peak width are updated at point A2, the welding parameters are updated so as to prioritize the appearance of weld bead 210, specifically, suppression of the occurrence of undercut 211 and humping bead 212.

[0137] On the other hand, when the peak current value and peak width are updated at point A1, the welding parameters are updated so as to give priority to suppression of the amount of spatter.

[0138] In other words, in the welding parameter adjustment method according to this embodiment, when there are multiple types of focus points in the welding quality, the processing from step S1 to step S13 shown in FIG. 14 is performed to perform a first update operation of updating the peak current value and peak width of the welding current so as to increase the number A of short circuits per unit time.

[0139] Furthermore, a second update operation is performed to update the values ​​of at least one welding parameter by performing the processes from step S21 to step S23 shown in Fig. 15. In this embodiment, the second update operation is performed to update the values ​​of the welding parameters so as to request the generation of a spatter amount. However, this is not particularly limited. The types and values ​​of the welding parameters to be adjusted are appropriately changed depending on the type of welding quality to be satisfied.

[0140] Of the first and second update operations, the operation of updating the value of the welding parameter having a greater effect on the welding quality is performed later. In other words, the order in which the first and second update operations are performed is determined according to the type of welding quality to be improved.

[0141] As described above, according to this embodiment, when the welding parameters are adjusted so as to satisfy each of the required specifications for a plurality of types of welding quality, the required specification for the welding quality having a high priority can be reliably satisfied.

[0142] In addition, if some or all of the welding parameters to be adjusted overlap with respect to different required welding quality specifications, it may be difficult to converge the values ​​of the welding parameters, and the number of trials may become too large.

[0143] On the other hand, according to the present embodiment, the order of the welding parameter value update operations is determined according to the type of welding quality and the improvement priority. Therefore, in each update operation, the welding parameter values ​​can be updated with an appropriate number of trials, and an excessive number of trials can be avoided. This reduces the man-hours and costs required for the welding parameter adjustment operation.

[0144] (Other embodiments) In the first to third embodiments, the welding parameters to be adjusted in order to suppress the occurrence of undercut 211 and humping bead 212 are the peak current value and peak width of the welding current, but this is not particularly limited, and the welding parameters to be adjusted may include the peak voltage value and peak width of the welding voltage. [Industrial Applicability]

[0145] The welding parameter adjustment method disclosed herein is useful because it can adjust welding parameters to suppress undercuts and humping beads without requiring shape measurement using a camera or the like. [Explanation of symbols]

[0146] 1 Input power supply (three-phase AC power supply) 2. Main transformer 3 Primary side rectifier 4 Switching section 5 DCL (reactor) 6 Secondary rectifier 7 Welding current detector 8 Welding voltage detector 9 Control Switching Unit 10 Output control section 11 Short circuit welding control unit 12 Pulse welding control unit 13 Wire feed speed control unit 14 Wire feed speed detector 15 Wire feed speed calculation section 16 Welding speed calculation section 20 Arc welding equipment 30 Torch 40 Wire feeder 50 Welding Wire 60 Robot 70 Power Cable 80 Arc 100 Welding parameter setting device 101 Input section 102 Output section 103 Storage section 104 Display section 105 Welding parameter setting section 106 Evaluation score calculation unit 107 Welding Parameter Estimation Section 108 Adjustment parameter selection section 109 Evaluation function setting section 110 Trial count setting section 111 Welding table setting section 112 Welding parameter readjustment section 200 Work 201 Molten Pool 210 Weld Bead 211 Undercut 212 Humping Bead 300 Arc Welding System

Claims

1. 1. A method for adjusting welding parameters for arc welding, comprising: A first step of setting a welding table corresponding to predetermined welding conditions; A second step of setting an evaluation index corresponding to welding quality; A third step of trial welding the workpiece based on the welding table set in the first step; a fourth step of measuring, during execution of said third step, a physical quantity related to one or more welding parameters included in said welding table; A fifth step of calculating an evaluation score for the evaluation index based on the physical quantity measured in the fourth step; A sixth step of determining whether or not to perform trial welding on the workpiece again; and a seventh step of estimating a value of the welding parameter corresponding to the evaluation index based on the evaluation score, the physical quantity being a welding current or a welding voltage or both; The evaluation index includes at least the number of short circuits per unit time, A series of processes from the third step to the seventh step are repeatedly executed, and at the start of each process, the value of the welding parameter corresponding to the evaluation index is changed based on the estimation result in the seventh step; a step of selecting the welding parameters having the highest evaluation score and updating the welding table after determining in the step of the sixth that a further trial welding is not necessary, and

2. 2. The welding parameter adjustment method according to claim 1, The welding parameter adjusting method, characterized in that, in performing the fourth step, a predetermined evaluation function is selected, and the evaluation index is evaluated with the evaluation function to obtain the evaluation score.

3. 2. The welding parameter adjustment method according to claim 1, A welding parameter adjustment method, comprising: comparing the evaluation score with the evaluation score obtained when a standard table is used; and displaying the comparison result.

4. 2. The welding parameter adjustment method according to claim 1, a welding parameter adjusting method for adjusting a welding parameter by selecting candidates for the welding parameter to be adjusted in accordance with changes in the welding conditions;

5. 2. The welding parameter adjustment method according to claim 1, A welding parameter adjustment method comprising the steps of: selecting candidates for the welding parameters to be adjusted in accordance with a required specification of the welding quality.

6. 2. The welding parameter adjustment method according to claim 1, The sixth step of the welding parameter adjustment method includes determining whether a preset number of trials has been reached.

7. 7. The welding parameter adjustment method according to claim 6, The method for adjusting welding parameters, comprising determining the number of trials based on the number of the welding parameters to be adjusted.

8. 2. The welding parameter adjustment method according to claim 1, When there are multiple points of focus for the welding quality, a first updating operation of updating a peak current value and a peak width of the welding current by performing the processes from the first step to the eighth step so as to increase the number of short circuits per unit time; A second update operation is performed by performing the processes from the first step to the eighth step to update the value of at least one of the welding parameters; a welding parameter adjusting method for adjusting a welding parameter value, the welding parameter value having a greater influence on the welding quality being updated later, of the first updating operation and the second updating operation.

9. an input unit for inputting at least a physical quantity related to one or more welding parameters and measured during arc welding of a workpiece; a welding parameter setting unit for setting the welding parameters corresponding to predetermined welding conditions; an evaluation score calculation unit that calculates an evaluation score regarding an evaluation index corresponding to the welding quality of the workpiece based on the physical quantity input to the input unit; a welding parameter estimation unit that estimates values ​​of the welding parameters to be adjusted based on the evaluation score, the physical quantity being a welding current or a welding voltage or both; A welding parameter setting device, wherein the evaluation index includes at least the number of short circuits per unit time.

10. 10. The welding parameter setting device according to claim 9, a storage unit configured to store at least one or more of the welding parameters corresponding to the welding conditions, the physical quantities input to the input unit, and the evaluation scores calculated by the evaluation score calculation unit; A welding parameter setting device further comprising: a display unit that displays at least the evaluation score.

11. 11. The welding parameter setting device according to claim 10, a welding table setting unit that sets a welding table, which is a group of the welding parameters corresponding to the welding conditions; an adjustment parameter selection unit for selecting the welding parameter to be adjusted; An evaluation function setting unit that sets an evaluation function for calculating the evaluation score; a trial number setting unit that sets the number of trial welding times of the workpiece required to estimate the value of the welding parameter.

12. an arc welding device for welding the workpiece; An arc welding system comprising at least the welding parameter setting device according to any one of claims 9 to 11.

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