Method for determining the state of a bond, device for determining the state of a bond

Abstract

To provide a joined state determination method and a joined state determination device capable of appropriately determining the joined state of a component.SOLUTION: This joined state determination method for determining the joined state of an arc-welded component (3) comprises: a step (S1) of acquiring welding current during arc-welding; a step (S2) of acquiring a welding voltage during the arc-welding; and a step (S6, S7, S12) of determining that the component is in a joined state when a welding voltage during a current stabilization period (AS) when the transition of the welding current is stable is within a preset joining determination voltage range (RV), and determining that the component is not in the joined state when the welding voltage is outside the joining determination voltage range.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a joint state determination method and a joint state determination device for determining the joint state of arc-welded parts.

Background Art

[0002] Conventionally, the quality of arc welding has been determined by measuring the welding current and voltage during arc welding. Further, for example, in Patent Document 1, it has also been proposed to determine the quality of arc welding by comparing the arc shape measured by a CCD camera during arc welding with the arc shape estimated based on the welding current and voltage.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the actual production site of products, although quality control is of course important, it is also very important to manage the manufacturing process. And when implementing the process of arc-welding parts, in addition to determining the quality of welding as in the prior art, it is important to determine whether the joint state of the parts affects the manufacturing process.

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a joint state determination method and a joint state determination device capable of appropriately determining the joint state of parts.

Means for Solving the Problems

[0006] A method for determining the joining state of arc-welded parts (3) includes the steps of: acquiring the welding current during arc welding (S1); acquiring the welding voltage during arc welding (S2); and determining that the parts are joined if the welding voltage during the current stabilization period (AS), in which the change in welding current is stable, is within a preset joining determination voltage range (RV), while determining that the parts are not joined if the welding voltage is outside the joining determination voltage range (S6, S7, S12). [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram showing the electrical configuration of a bonding state determination device according to one embodiment. [Figure 2] A schematic diagram showing an example of the installation of a bonding condition determination device on a manufacturing line. [Figure 3] Diagram showing the process flow for determining the bonding state. [Figure 4] Figure 1 illustrates the method for determining the bonding state. [Figure 5] Figure 2 illustrates the method for determining the bonding state. [Modes for carrying out the invention]

[0008] The embodiments will now be described with reference to the drawings. As shown in Figure 1, the joint state determination device 1 of this embodiment determines the joint state between members when arc welding is performed by the arc welding device 2. Hereinafter, one of the members to be arc-welded will be referred to as part 3, and the other member to which part 3 is welded will be referred to as another part 4.

[0009] The arc welding apparatus 2 performs arc welding by applying a voltage while there is a predetermined gap (G) between the welding electrode 7 of the welding torch 6 connected to the welding power supply device 5 and the member to which, for example, a clamp electrode 8 is attached. In this embodiment, TIG (Tungsten Inert Gas) welding is assumed. TIG welding is a method in which non-consumable tungsten is used as the welding electrode 7 provided on the welding torch 6, and members are welded by melting a welding rod, which is used as filler material, with an arc.

[0010] The welding power supply unit 5 includes a control circuit 10, a welding power output circuit 11, a monitor output circuit 12, etc. When a welding start signal is input from an external device (not shown) connected to the terminal block 13, the welding power output circuit 11 outputs a predetermined welding voltage. At this time, the monitor output circuit 12 outputs a monitor voltage corresponding to the welding voltage to the terminal block 13. The monitor voltage is a differential output signal that converts a welding voltage range, for example, from 5[V] to 100[V], to a range, for example, from 0[V] to 5[V], so that the welding voltage can be monitored by an external device, such as the joint state determination device 1. Note that the configuration of the welding power supply unit 5 is an example.

[0011] The junction state determination device 1 includes a control unit 20, a storage unit 21, a current detection circuit 22, a voltage detection circuit 23, and the like. The control unit 20 is configured by a computer and controls the entire junction state determination device 1. The control unit 20 also includes a current acquisition unit 24, a voltage acquisition unit 25, a determination unit 26, and a notification unit 27. In this embodiment, the current acquisition unit 24, the voltage acquisition unit 25, the determination unit 26, and the notification unit 27 are implemented by software executed by the control unit 20.

[0012] The current acquisition unit 24 acquires the welding current by converting the output signal from the current sensor 9, which is provided on the cable 8a to which the clamp electrode 8 is connected, using the current detection circuit 22. The voltage acquisition unit 25 acquires the welding voltage by converting the monitor voltage using the current detection circuit 22. The acquired welding current and welding voltage are stored in the storage unit 21 in chronological order.

[0013] The determination unit 26, as will be described in detail later, determines the joining state of part 3 based on the acquired welding current and welding voltage. This determination unit 26 determines that a state in which the arc-welded part 3 is unlikely to come off or is unlikely to come off is a joined state, and that a state in which the arc-welded part 3 is likely to come off or is highly likely to come off is an unjoined state. Hereinafter, the state in which part 3 is joined will simply be referred to as joined, and the state in which part 3 is not joined will be referred to as unjoined.

[0014] The notification unit 27 notifies the determination result of the determination unit 26, indicating whether the parts are joined or not. The notification unit 27 notifies the determination result by means of, for example, displaying it on a display device 30 such as a display, lighting a warning lamp 31, sounding a buzzer 32, or outputting a signal to a control device 33 that manages the manufacturing line 40. In this embodiment, the notification unit 27 notifies at least when it is necessary to stop the manufacturing line 40, that is, when the parts 3 are not joined. Note that the notification methods shown here are just examples and do not necessarily have to be all of them, and other notification methods can also be adopted.

[0015] Such a joint state determination device 1 is installed, for example, in a manufacturing line 40 as shown in Figure 2. In this manufacturing line 40, as indicated by the black arrows, a separate part 4 is transported by a transport device 41 to a predetermined welding position (P). When the separate part 4 is transported to the welding position, a holding robot 42, acting as a holding device, takes part 3 from, for example, a parts box 43 and holds part 3 in a holding position for welding to the separate part 4. Once part 3 is held in the holding position, a welding robot 44 arc-welds part 3 to the separate part 4 while moving the welding torch 6 to a predetermined position. When arc welding is completed, the separate part 4 with part 3 welded to it is transported from the welding position (P) to the next process. However, the configuration of the manufacturing line 40 shown in Figure 2 is just an example and is not limited thereto.

[0016] Next, the operation and effects of the above configuration will be explained. As described above, in an actual manufacturing site, although quality control is of course important, it also becomes very important to manage the manufacturing process. When arc welding the component 3, it becomes important to determine whether the joining state of the arc-welded component 3 affects the manufacturing process.

[0017] For example, in the case of the manufacturing line 40 shown in FIG. 2, the component 3 is arc-welded to another component 4 while being held at the holding position, and then the other component 4 is conveyed to the subsequent process by the conveying device 41. In this case, if the joining of the component 3 is insufficient and the component 3 falls off, it may affect the manufacturing process, such as making it impossible to perform the work in the subsequent process. Also, if the component 3 falls off when the holding robot 42 releases the component 3 after arc welding or when being conveyed by the conveying device 41, there is a possibility that the component 3 may be sandwiched by the conveying device 41 or the conveying device 41 may be damaged. That is, the dropping of components may cause unintended problems such as significantly stopping the manufacturing line 40, and in that case, it will have a great impact on the manufacturing process.

[0018] Therefore, when the joining of the component 3 is insufficient, that is, when there is a possibility that the component 3 may fall off, it is desirable to take measures against the dropping of the component 3, such as not releasing the held component 3 or not conveying it after arc welding.

[0019] However, the possibility of the component 3 falling off may not always coincide with the determination result of the quality of arc welding. For example, when it is determined that the quality is good, since it is considered that the joining of the component 3 is also sufficient, it can be determined that the possibility of the component 3 falling off is none or very low. That is, when it is determined that the quality is good, it is considered that the possibility of affecting the manufacturing process is low.

[0020] On the other hand, when it is determined that the quality is defective, if the joining of part 3 is insufficient, a situation is assumed where part 3 will fall off when it is separated after arc welding. Also, depending on the degree of joining, a situation is assumed where part 3 will fall off due to vibration applied during conveyance. Also, even when it is determined that the quality is defective, a situation is assumed where the joining of part 3 is sufficient and there is no possibility or a low possibility that part 3 will fall off. That is, in the conventional determination of the quality of welding, although quality can be determined, it does not assume part dropout and does not accurately reflect the joining state of parts that affect the manufacturing process.

[0021] Therefore, in view of the above problems in the actual manufacturing site, the joining state determination device 1 newly adopts a determination criterion different from the conventional determination criterion for quality control, enabling appropriate determination of the joining state of part 3. Specifically, the joining state determination device 1 executes the joining state determination process shown in FIG. 3. Each process shown in FIG. 3 is executed by the current acquisition unit 24, voltage acquisition unit 25, determination unit 26, or notification unit 27, but for simplicity of explanation, it will be described below mainly with the joining state determination device 1 as the main body.

[0022] Here, in order to facilitate understanding of the flow of the process shown in FIG. 3, first, each term will be explained while referring to FIGS. 4 and 5. The current stabilization period (AS) in the joining determination process means, as shown by graph G1A in FIG. 4, the period during which the welding current during arc welding transitions within the current determination range (RA) defined by the preset upper current value (RA-H) and lower current value (RA-L).

[0023] Also, the duration (ΔT) means, as shown by graph G1V in FIG. 4, the time during which the welding voltage during the current stabilization period continuously transitions within the joining determination voltage range (RV) defined by the preset upper voltage value (RV-H) and lower voltage value (RV-L). In FIGS. 4 and 5, for the sake of distinction, it is shown as duration (ΔT1), duration (ΔT2), duration (ΔT3), and duration (ΔT4).

[0024] In this embodiment, the joint determination voltage range is set as a welding voltage range in which there is no possibility of part 3 being lost when transporting another part 4 after arc welding, or in which the possibility of part 3 being lost is considered low. Furthermore, the joint determination voltage range is preset based on at least one of the shape, material, or weight of part 3, and the determination unit 26 is configured to change the joint determination voltage range according to at least one of the shape, material, or weight of part 3.

[0025] This joint detection voltage range is predetermined by prior testing. For example, graph G2V in Figure 4 shows the welding voltage when no arc is generated, and graph G2A shows the welding current in that state. As can be seen from graph G2A, the welding current, even when no arc is generated, is roughly the same as the welding current when an arc is generated, as shown in graph G1A. On the other hand, the welding voltage shown in graph G2V deviates significantly from the welding voltage when an arc is generated, as shown in graph G1V, when no arc is generated. In other words, by obtaining the welding voltage, it is possible to determine whether or not an arc is generated.

[0026] Then, by repeatedly performing preliminary tests while changing the welding voltage, for example by changing the gap length, it is possible to determine the welding voltage range in which part 3 is stably joined and the time in which part 3 is stably joined. This range is set as the joining determination voltage range, and this time is set as the determination time (Tv). In this embodiment, the joining determination voltage range is set to be a range in which the welding state is such that there is a low possibility of part 3 coming off when the holding device releases part 3, and also a range in which the welding state is such that there is a low possibility of part 3 coming off during transport. In other words, the joining determination voltage range in this embodiment is set to be a range in which it is possible to determine whether or not part 3 will come off when arc-welded.

[0027] Therefore, if the welding voltage during the current stabilization period remains within the joint determination voltage range and continues beyond the determination time, it can be determined that there is no loss of the arc-welded part 3, or that the possibility of part 3 losing its part is low, in other words, that part 3 is joined.

[0028] Furthermore, the total duration refers to the sum of the individual durations measured during a single welding cycle, for example, as shown in Figure 5. In this embodiment, the total duration is the sum of the durations exceeding a preset minimum judgment time (Tvmin). This minimum judgment time is determined in advance through a preliminary test as the time at which it can be determined that the joint is melted, and is stored in the memory unit 21 or the like.

[0029] Next, the specific details of the joint determination process will be explained. When the joint state determination device 1 starts processing, it acquires the welding current (S1) and the welding voltage (S2). At this time, the joint state determination device 1 stores the welding current and welding voltage acquired at the same time in the storage unit 21, corresponding to the acquisition time. Note that steps S1 and S2 can be performed in any order.

[0030] Next, the joining state determination device 1 determines whether it is a current stabilization period (S3). In the case of Figure 4, the joining state determination device 1 identifies the period from time (t2), when it is confirmed that the welding current reaches the current determination range at time (t1) after the start of one welding cycle and that the welding current acquired over multiple times has continuously remained within the current determination range, until time (t5), when the welding current falls outside the current determination range, as the current stabilization period. Note that there may be multiple current stabilization periods within a single welding cycle. Alternatively, the start time of the current determination range may be determined by checking the fluctuation rate of the welding current or by checking whether it is within the current determination range in multiple samples taken after time (t2).

[0031] For example, immediately after the welding cycle has started, the joint status determination device 1 determines whether the duration is being measured (S10) because it is not the current stabilization period (S3:NO). The joint status determination device 1 determines that the component 3 is not joined (S12) because the duration measurement has not yet started immediately after the welding cycle has started (S10:NO) and the duration has not exceeded the determination time (S6:NO). In other words, the joint status determination device 1 determines that the component 3 is not joined at this time.

[0032] Next, if the welding cycle is not complete (S8: NO), the joining state determination device 1 proceeds to step S1 and repeats processes such as acquiring the welding current, acquiring the welding voltage, and determining whether it is the current stabilization period. Then, if the joining state determination device 1 determines that it has entered the current stabilization period at the time (t2) shown in Figure 4 (S3: YES), it determines whether the welding voltage is within the joining determination voltage range (S4). At this time, the joining state determination device 1 sets an appropriate range for the joining determination voltage range according to at least one of the shape, material, or weight of the part 3.

[0033] The joint state determination device 1 measures the duration (ΔT1) (S5) if, for example, the welding voltage (V1) acquired at time (t3) is within the joint determination voltage range (S4:YES). While the time (t3) at which the acquisition of the welding voltage begins could be the same as the time (t2) at which the current stabilization period begins, in this embodiment, in order to more accurately measure the duration (ΔT1), the measurement of the duration (ΔT1) is started from time (t3) because the rate of change of the welding voltage after time (t2) is checked, and confirmation that it is within the joint determination voltage range is performed through multiple samples taken after time (t2).

[0034] Next, if the current stabilization period continues (S3:YES) and the welding voltage remains within the joint determination voltage range (S4:YES), the joint state determination device 1 measures the duration (ΔT1) (S5). In this case, the joint state determination device 1 continues measuring the duration (ΔT1).

[0035] Then, the joint state determination device 1 determines that a joint has been formed (S6:YES) if the welding voltage (Vn) acquired from time (t3) to time (t4) after the determination time has elapsed has remained within the joint determination voltage range, since the duration (ΔT1) has exceeded the determination time. In other words, the joint state determination device 1 determines that the arc-welded part 3 is in a state where it will not fall off, or where the possibility of it falling off is low.

[0036] In contrast, the joining state determination device 1 determines that the joint is not joined (S12) if, for example, the welding current shown in graph G2A in Figure 4 is within the current stability range (S3:YES), but the welding voltage shown in graph G2V continues to be outside the joining determination voltage range (S4:NO), because the measurement of the duration has not been started (S10:NO) and the duration has not exceeded the determination time (S6:NO). In other words, the joining state determination device 1 determines that the part 3 is not sufficiently joined and that there is a possibility that the part 3 may fall off after arc welding.

[0037] Furthermore, the joining state determination device 1 starts measuring the duration (ΔT2) if, for example, the welding current shown in graph G3A in Figure 5 is within the current stability range, and the welding voltage (V2) at time (t11) is within the joining determination voltage range, as shown in graph G3V. Then, if the welding voltage (V2n) acquired at time (t15) is outside the joining determination voltage range, the joining state determination device 1 terminates the measurement (S10:YES) because it is still measuring the duration (ΔT2), and determines the duration (ΔT2) to be up to the time (t14) when the welding voltage (V2n-1) immediately before it was within the joining determination voltage range was acquired.

[0038] The bonding state determination device 1 determines that bonding has occurred if the duration (ΔT2) exceeds the determination time (S6:YES), while determining that bonding has not occurred if the duration (ΔT2) does not exceed the determination time (S6:NO), as shown in Figure 5 (S12). Furthermore, suppose that the welding voltage (V31) acquired at time (t16) falls within the joint determination voltage range again, and continues to fall within the joint determination voltage range until the welding voltage (V3n) acquired at time (t18). In this case, the joint state determination device 1 can be configured to determine the duration (ΔT3) and, if the sum of that duration (ΔT3) and the aforementioned duration (ΔT2) reaches the determination time, determine that a joint has been formed. Of course, if the joint state determination device 1 continues to fall within the joint determination voltage range until the welding voltage (V3n+α) acquired after the determination time has elapsed from time (t16), it will determine that a joint has been formed if that duration (ΔT4) reaches the determination time.

[0039] In other words, the joining state determination device 1 determines that the part 3 is joined if it confirms at least one instance of a duration exceeding the determination time during a single welding cycle, or if the total duration during a single welding cycle exceeds the determination time. In this case, in step S6, it is sufficient to determine whether any of the durations exceeded the determination time, and whether the total duration, which is the sum of the durations, exceeded the determination time.

[0040] Thus, the determination of the joint status is performed before the welding cycle is completed. After determining whether the joint status is joined or not, the joint status determination device 1 notifies the determination result (S9) when the welding cycle is completed (S8:YES). At this time, if it is determined that the joint status is not joined, continuing the process as is may lead to damage to the equipment, so the device will display a warning on the display device 30, sound the buzzer 32, or output a signal to the control device 33 to notify it that it should stop. For example, the joint status determination device 1 can output a signal to the control device 33 that controls the transport device 41 to stop, or output a signal to the controller of the holding robot 42 to instruct it not to release the part 3. It is also possible to configure the device to not notify if the joint status is not met, and only notify if the joint status is not met.

[0041] According to the embodiments described above, the following effects can be obtained. A method for determining the joining state of an arc-welded part 3 includes the steps of: acquiring the welding current during arc welding; acquiring the welding voltage during arc welding; and determining that the part 3 is joined if the welding voltage during the current stabilization period, when the change in welding current is stable, is within a preset joining determination voltage range, while determining that the part 3 is not joined if the welding voltage is outside the joining determination voltage range.

[0042] This allows for a proper assessment of the joint condition of part 3, which could not always be determined by conventional quality-based welding assessments, and thus reduces the risk of part 3 coming loose, thereby reducing the potential impact on the manufacturing process. Furthermore, since the joint condition is assessed before the welding cycle is completed, it becomes possible to address the issue of part 3 coming loose before it affects equipment or subsequent processes.

[0043] Furthermore, the joining state determination device 1 for determining the joining state of arc-welded parts 3 includes a current acquisition unit 24 that acquires the welding current during arc welding, a voltage acquisition unit 25 that acquires the welding voltage during arc welding, and a determination unit 26 that determines that parts 3 are joined if the welding voltage during the current stabilization period when the change in welding current is stable is within a preset joining determination voltage range, and determines that parts 3 are not joined if the welding voltage is outside the joining determination voltage range.

[0044] This joint state determination device 1 can appropriately determine the possibility of component 3 being missing, thereby reducing the risk of affecting the manufacturing process. Furthermore, since the joint state is determined before the welding cycle is completed, it becomes possible to take action before the missing component 3 affects the equipment or subsequent processes, thus achieving the same effects as the joint state determination method described above.

[0045] Furthermore, if the duration during which the welding voltage remains within the joint determination voltage range is defined as the duration, the determination unit 26 determines that the component 3 is joined when the duration reaches a preset determination time. This allows the joint status to be determined while suppressing the influence of noise and other factors, thereby improving the accuracy of the determination.

[0046] Furthermore, if the duration during which the welding voltage remains within the joint determination voltage range is defined as the duration during the current stabilization period, the determination unit 26 determines that the part 3 is joined when the total duration, which is calculated as the sum of the durations exceeding a preset minimum determination time, reaches a preset determination time. This allows for appropriate determination of the joint state even when there are defects during arc welding, when welding irregularly shaped part 3, the welding voltage fluctuates significantly, or when welding multiple small welding areas.

[0047] Furthermore, part 3 is arc-welded while held in a predetermined holding position by a holding device, and the joint determination voltage range is set to a welding voltage range in which there is no possibility, or a low possibility, of part 3 falling off when the holding device releases part 3 after arc welding. This makes it possible to determine whether it is safe to release part 3 after arc welding, and to avoid in advance the risk of part 3 falling off when released, which could affect the equipment or manufacturing process.

[0048] Furthermore, part 3 is arc-welded to another part 4, and the other part 4 is transported by a transport device 41. The joining determination voltage range is set to a welding voltage range in which there is no possibility, or a low possibility, of part 3 being lost when transporting the other part 4 after arc welding. This makes it possible to determine whether it is safe to transport the other part 4 after arc welding, and to avoid in advance the risk of part 3 being dropped during transport and affecting the equipment or manufacturing process.

[0049] Furthermore, the joint state determination device 1 is further equipped with a notification unit 27 that notifies the determination result from the determination unit 26. This makes it possible, for example, to notify workers and managers on the manufacturing line 40 of the risk of part 3 falling off via screen or sound, to output a stop signal to the management device 33 that controls the transport device 41, or to instruct the controller of the holding robot 42 not to let go of part 3, thereby preventing in advance the risk of part 3 falling and affecting the equipment or manufacturing process.

[0050] The embodiments described above are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0051] In the embodiment, a configuration was shown that determines a joint has been formed if a duration exceeding the judgment time is confirmed during a single welding cycle. However, the configuration can be adapted to determine a joint if multiple durations exceeding the judgment time are confirmed.

[0052] In this embodiment, a configuration is shown in which the joint determination process continues even if a joint is determined to have been formed. However, the configuration can be set to terminate as soon as a joint is determined to have been formed. However, if a joint is not determined to have been formed, the process will continue until the completion of the welding cycle, or until the remaining time until the scheduled completion time of the welding cycle becomes less than the determination time. Furthermore, for example, if an operator transports the product after arc welding, there is considered to be some time leeway after the completion of arc welding, so the configuration can be set to determine whether a joint has been formed or not after the completion of the welding cycle. The scheduled completion time of the welding cycle can be obtained from the controller of the welding robot 44 or a higher-level management device 33, etc.

[0053] In this embodiment, a joint determination voltage range was set that results in a weld state where there is a low probability of the part 3 falling off when the holding device releases it, and a joint determination voltage range that results in a weld state where there is a low probability of the part 3 falling off during transport. However, these two ranges can be set to different ranges. In other words, the joint determination voltage range can be set or selected as appropriate according to the actual work content.

[0054] In this embodiment, an example is shown in which a separate part 4 is transported by a transport device 41. However, if an operator transports the separate part 4, the joining state determination device 1 can be applied to a manufacturing process in which the part is brought to the welding position and then removed after arc welding. In this case, the joining determination voltage range should be set to a welding voltage range in which there is no possibility of part 3 falling off when the holding robot 42 releases part 3 after arc welding, or in which there is a low possibility of part 3 falling off.

[0055] The control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the control unit and its method described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium. [Explanation of symbols]

[0056] In the drawing, 1 is a joint state determination device, 3 is a component, 4 is a separate component, 24 is a current acquisition unit, 25 is a voltage acquisition unit, 26 is a determination unit, 27 is a notification unit, 41 is a conveying device, and 42 is a holding robot (holding device).

Claims

1. A method for determining the joint state of arc-welded parts (3), The process of acquiring the welding current during arc welding (S1), The process of acquiring the welding voltage during arc welding (S2), The process includes the steps (S6, S7, S12) of determining that the component is joined if the welding voltage during the current stabilization period (AS), in which the change in the welding current is stable, is within a preset joining determination voltage range (RV), while determining that the component is not joined if the welding voltage is outside the joining determination voltage range. If the duration (ΔT) is defined as the time during which the welding voltage continuously remains within the joining determination voltage range during the current stabilization period, The bonding state determination method, in the determination step, determines that the parts are bonded when the duration reaches a predetermined determination time (Tv).

2. A method for determining the joint state of arc-welded parts (3), The process of acquiring the welding current during arc welding (S1), The process of acquiring the welding voltage during arc welding (S2), The process includes the steps (S6, S7, S12) of determining that the component is joined if the welding voltage during the current stabilization period (AS), in which the change in the welding current is stable, is within a preset joining determination voltage range (RV), while determining that the component is not joined if the welding voltage is outside the joining determination voltage range. If the duration (ΔT) is defined as the time during which the welding voltage continuously remains within the joining determination voltage range during the current stabilization period, The bonding state determination method, in the determination step, determines that the parts are bonded when the total duration, which is the sum of the durations exceeding a preset minimum determination time (Tvmin), reaches a preset determination time (Tv).

3. A joint state determination device (1) for determining the joint state of arc-welded parts (3), A current acquisition unit (24) that acquires the welding current during arc welding, A voltage acquisition unit (25) that acquires the welding voltage during arc welding, The system includes a determination unit that determines that the component is joined if the welding voltage during the current stabilization period (AS), in which the welding current is stable, is within a preset joining determination voltage range (RA), and determines that the component is not joined if the welding voltage is outside the joining determination voltage range. If the duration (ΔT) is defined as the time during which the welding voltage continuously remains within the joining determination voltage range during the current stabilization period, The determination unit is a bonding state determination device that determines that the parts are bonded when the duration reaches a predetermined determination time (Tv).

4. A joint state determination device (1) for determining the joint state of arc-welded parts (3), A current acquisition unit (24) that acquires the welding current during arc welding, A voltage acquisition unit (25) that acquires the welding voltage during arc welding, The system includes a determination unit that determines that the component is joined if the welding voltage during the current stabilization period (AS), in which the welding current is stable, is within a preset joining determination voltage range (RA), and determines that the component is not joined if the welding voltage is outside the joining determination voltage range. If the duration (ΔT) is defined as the time during which the welding voltage continuously remains within the joining determination voltage range during the current stabilization period, The determination unit determines that the parts are joined when the total duration, which is calculated as the sum of the durations exceeding a preset minimum determination time (Tvmin), reaches a preset determination time (Tv).

5. The aforementioned part is arc-welded while being held in a predetermined holding position. The joint state determination device according to claim 3 or 4, wherein the joint determination voltage range is set as a welding voltage range in which there is no possibility of the part falling off when the part is separated after arc welding, or in which there is a low possibility of the part falling off.

6. The aforementioned part is arc-welded to another part (4), The aforementioned separate component is transported by the transport device (41), The joint state determination device according to claim 3 or 4, wherein the joint determination voltage range is set as a welding voltage range in which there is no possibility of the component being lost when transporting the other component after arc welding, or in which there is a low possibility of the component being lost.

7. The bonding state determination device according to claim 3 or 4, further comprising a notification unit (27) for notifying the determination result by the determination unit.

8. The junction determination voltage range is set in advance based on at least one of the shape, material, or weight of the component. The bonding state determination device according to claim 3 or 4, wherein the determination unit changes the bonding determination voltage range according to at least one of the shape, material, or weight of the component.

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