Arc-welding method
The arc welding method addresses hole defects in welds by dynamically adjusting conditions based on hole state changes, ensuring only non-closing holes are repaired, thus enhancing weld quality and yield.
Patent Information
- Application Number
- JP2024044783
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-03-21
- Publication Date
- 2025-10-03
AI Technical Summary
Existing arc welding methods for joining heat sinks and fins often result in hole defects in the weld bead, which can lead to quality variations and reduced yield due to the need for repairing all holes during welding.
An arc welding method that monitors the state of holes in the molten pool during welding and adjusts conditions based on the rate of change of hole parameters, only repairing holes that are unlikely to close naturally, thereby suppressing defects and quality issues.
This approach effectively reduces the occurrence of hole defects and associated quality variations by selectively repairing only those holes that will not close naturally, maintaining weld integrity and yield.
Smart Images
Figure 2025144880000001_ABST
Abstract
Description
[Technical Field]
[0001] An embodiment of the present invention relates to an arc welding method. [Background technology]
[0002] For example, when joining a heat sink and a fin by arc welding, holes may occur in the weld bead after welding. One way to prevent these holes from occurring is to repair holes that occur in the molten pool during welding. However, repairing all holes that occur in the molten pool during welding can lead to problems such as variations in quality and reduced yield. [Prior art documents] [Non-patent literature]
[0003] [Patent Document 1] Japanese Patent Publication No. 2022-105404 Summary of the Invention [Problem to be solved by the invention]
[0004] The problem to be solved by the present invention is to provide an arc welding method that can suppress the occurrence of hole defects and the occurrence of problems due to repair. [Means for solving the problem]
[0005] An arc welding method according to an embodiment is a method for performing arc welding by overlapping a first portion of a second material to be welded, the first portion having a flat plate-like first portion, with a first material to be welded that is flat. The arc welding method according to an embodiment includes an acquisition step and an adjustment step. In the acquisition step, a rate of change of a parameter indicating the state of a hole that has occurred in a molten pool is acquired while arc welding is performed by overlapping the second material to be welded with the first material to be welded. In the adjustment step, the arc welding conditions are adjusted based on the rate of change. In the adjustment step, if the absolute value of the rate of change is equal to or greater than a first threshold, the conditions are not changed, and if the absolute value of the rate of change is less than the first threshold, the conditions are changed. [Brief explanation of the drawings]
[0006] [Figure 1] 1 is a perspective view schematically illustrating an arc welding method according to an embodiment. [Figure 2] 2(a) and 2(b) are a plan view and a cross-sectional view, respectively, that schematically show a case where no hole is formed in the molten pool in the arc welding method according to the embodiment. [Figure 3] 3(a) and 3(b) are a plan view and a cross-sectional view, respectively, that schematically show a case where a hole is formed in a molten pool in an arc welding method according to an embodiment. [Figure 4] 4(a) to 4(c) are plan views that schematically show changes in the state of a hole formed in a molten pool in an arc welding method according to an embodiment. [Figure 5] 2 is a flowchart illustrating an example of an arc welding method according to the first embodiment. [Figure 6] 10 is a flowchart illustrating an example of an arc welding method according to a second embodiment. [Figure 7] 10 is a flowchart illustrating an example of an arc welding method according to a third embodiment. [Figure 8] 10 is a flowchart illustrating an example of an arc welding method according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION
[0007] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In this specification and in each drawing, elements similar to those previously described with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.
[0008] FIG. 1 is a perspective view schematically illustrating an arc welding method according to an embodiment. 1, the arc welding method according to the embodiment is a method of performing arc welding by overlapping a first material to be welded 11 with a second material to be welded 12. Hereinafter, the first material to be welded 11 and the second material to be welded 12 will be collectively referred to as the welding object S.
[0009] Arc welding methods according to the embodiments include, for example, arc welding methods using TIG (Tungsten Inert Gas) welding, MIG (Metal Inert Gas) welding, MAG (Metal Active Gas) welding, and carbon dioxide arc welding.
[0010] The first material to be welded 11 has a flat plate shape. The first material to be welded 11 is, for example, a heat sink. The first material to be welded 11 is, for example, a panel to be joined to a fin.
[0011] The second material to be welded 12 has, for example, a first portion 12a and a second portion 12b. The first portion 12a is flat. The second portion 12b is an upright portion rising from the first portion 12a. The second portion 12b extends, for example, in a direction perpendicular to the first portion 12a. The second material to be welded 12 is, for example, a fin.
[0012] In the arc welding method according to the embodiment, the first portion 12a of the second material to be welded 12 is superimposed on the first material to be welded 11, and the welding rod 35 is melted and dripped by the torch 30, thereby joining the first material to be welded 11 to the second material to be welded 12.
[0013] The torch 30 is provided with a metal electrode 31. The tip of the electrode 31 is exposed from the torch 30. When a voltage is applied between the electrode 31 and the object to be welded S, an arc discharge occurs. One of the electrode 31 and the object to be welded S may be set to a common potential (for example, ground potential), and only the potential of the electrode 31 and the object to be welded S may be controlled.
[0014] The welding rod 35 is, for example, a metal wire. The tip of the welding rod 35 is placed in a space where an arc discharge is occurring. The arc discharge melts the tip of the welding rod 35 and drips onto the welding object S. The molten welding rod 35 solidifies, thereby welding the welding object S.
[0015] In the arc welding method according to the embodiment, welding is performed while an image of the area where welding is being performed (welded area) is captured by a camera 40. The image may be a still image or a video image. The camera 40 includes, for example, a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor. The image may be captured while illuminating the area where welding is being performed with a lighting device, if necessary.
[0016] In the arc welding method according to the embodiment, welding is performed while moving torch 30 and welding rod 35 along first direction D1, which is the direction along which the boundary between first material to be welded 11 and second material to be welded 12 extends. Furthermore, by moving camera 40 along first direction D1 together with torch 30 and welding rod 35, welding can be performed while continuously capturing images of the welding point, the position of which changes along first direction D1.
[0017] In this arc welding method, a molten pool 20 is formed by the metal molten from the welding rod 35 and a portion of the welding object S melted by this metal. When the molten pool 20 solidifies, it becomes a bead.
[0018] 2(a) and 2(b) are a plan view and a cross-sectional view, respectively, that schematically show a case where no hole is formed in the molten pool in the arc welding method according to the embodiment. 3(a) and 3(b) are a plan view and a cross-sectional view, respectively, that schematically show a case where a hole is formed in a molten pool in an arc welding method according to an embodiment. FIG. 2(b) is a cross-sectional view taken along line A1-A2 shown in FIG. 2(a). FIG. 3(b) is a cross-sectional view taken along line B1-B2 shown in FIG. 3(a).
[0019] As shown in Figures 2(a), 2(b), 3(a), and 3(b), a hole 21 may occur in the molten pool 20 during arc welding. In Figures 2(b) and 3(b), the boundary of the area where arc discharge occurs is indicated by a two-dot chain line. Arc discharge occurs inside the area surrounded by the two-dot chain line.
[0020] The hole 21 occurs, for example, when excessive heat is input to the first portion 12a of the second material to be welded 12, causing the first portion 12a to melt down. If the molten pool 20 solidifies without closing the hole 21, a hole defect occurs in the bead.
[0021] 4(a) to 4(c) are plan views that schematically show changes in the state of a hole formed in a molten pool in an arc welding method according to an embodiment. As shown in FIGS. 4(a) to 4(c), the state of the hole 21 changes while arc welding is being performed.
[0022] When the fluidity of the molten pool 20 is high, the hole 21 may, for example, change from a medium size as shown in FIG. 4(a) to a large size as shown in FIG. 4(b) or to a small size as shown in FIG. 4(c). When the fluidity of the molten pool 20 is high, the size and shape of the hole 21 tend to change over time. In this state, the hole 21 tends to close naturally over time. In other words, such a hole 21 that tends to close naturally is unlikely to remain as a hole defect even if repair is not performed.
[0023] On the other hand, when the fluidity of the molten pool 20 decreases, the size of the hole 21 will not change from, for example, the size shown in any one of Figures 4(a) to 4(c). In other words, when the fluidity of the molten pool 20 is low, the size and shape of the hole 21 will not change easily even over time. In this state, the hole 21 will not close naturally even over time. In other words, if such a hole 21 that is difficult to close naturally is not repaired, it will likely remain as a hole defect.
[0024] One way to prevent the occurrence of hole defects is to repair holes 21 that appear in the molten pool 20 during welding. However, repairing all holes 21 that appear in the molten pool 20 during welding can lead to problems such as variations in quality and reduced yield.
[0025] Therefore, in the arc welding method according to the embodiment, instead of repairing all holes 21 that occur in the molten pool 20 during welding, only holes 21 that are difficult to close naturally are repaired. Specifically, the arc welding method according to the embodiment includes an acquisition step of acquiring information about the state of the holes 21, and an adjustment step of adjusting the arc welding conditions based on the information.
[0026] More specifically, in the acquisition process, the rate of change of a parameter indicating the state of a hole 21 formed in the molten pool 20 is acquired while arc welding is being performed by overlapping the second weld material 12 on the first weld material 11. In the acquisition process, the rate of change of the parameter indicating the state of the hole 21 formed in the molten pool 20 is acquired based on, for example, an image of the welding point taken by the camera 40.
[0027] The parameters indicating the state of the hole 21 include, for example, at least one of a parameter indicating the size of the hole 21 and a parameter indicating the shape of the hole 21. The parameters indicating the state of the hole 21 include, for example, at least one of an area of the hole 21, a circularity of the hole 21, and an aspect ratio of the hole 21.
[0028] In the acquisition step, holes are identified by, for example, image processing. In the image processing, for example, a portion of an image of a welding point whose brightness is equal to or less than a predetermined value is determined to be a hole. This makes it possible to acquire the area, circularity, aspect ratio, etc. of the hole 21. For example, by performing image processing on multiple images acquired at different times, it is possible to acquire the rate of change of parameters indicating the state of the hole 21 (such as the rate of change of the area of the hole 21, the rate of change of the circularity of the hole 21, and the rate of change of the aspect ratio of the hole 21).
[0029] Furthermore, in the acquisition step, holes may be identified based on a model created by machine learning, for example. The model is created by machine learning using, for example, images of welded portions that include holes and images of welded portions that do not include holes as training data. This makes it possible to acquire the area, circularity, aspect ratio, etc. of the hole 21. For example, by making a judgment based on the model on multiple images acquired at different times, it is possible to acquire the rate of change of parameters that indicate the state of the hole 21 (such as the rate of change of the area of the hole 21, the rate of change of the circularity of the hole 21, and the rate of change of the aspect ratio of the hole 21).
[0030] For example, the parameter at the first time is the first parameter P1, and the parameter at the second time is the second parameter P2. The rate of change from the first parameter P1 to the second parameter P2 is expressed as the ratio of the difference between the first parameter P1 and the second parameter P2 to the first parameter P1 (100×(P2−P1) / P1[%]).
[0031] FIG. 5 is a flowchart illustrating an example of the arc welding method according to the first embodiment. 5, in the arc welding method according to the first embodiment, when welding is started, images of the welding point are successively acquired. Specifically, a first image is acquired at a first time, and a second image is acquired at a second time (step S101). The second time is a time later than the first time.
[0032] Next, a first parameter which is a parameter indicating the state of the hole 21 at a first time is acquired from the first image, and a second parameter which is a parameter indicating the state of the hole 21 at a second time is acquired from the second image (step S102). More specifically, for example, a first area which is the area of the hole 21 at the first time is acquired from the first image, and a second area which is the area of the hole 21 at the second time is acquired from the second image.
[0033] Next, the rate of change from the first parameter to the second parameter is obtained (step S103). More specifically, for example, the rate of change from the first area to the second area is obtained. The rate of change is expressed as 100 × (first area - second area) / first area [%].
[0034] Next, it is determined whether the absolute value of the rate of change is equal to or greater than a first threshold value (step S104). When the parameter is the area of the hole 21, the first threshold value is set to, for example, 18%. For example, by setting the first threshold value to 18%, it is possible to perform the determination with high accuracy (for example, accuracy of 60% or more).
[0035] If the absolute value of the rate of change is equal to or greater than the first threshold (step S104: Yes), it is determined whether the second parameter is less than the second threshold (step S105). If the parameter is the area of the hole 21, the second threshold is set to, for example, 20,000 pixels. For example, by setting the second threshold to 20,000 pixels, it is possible to perform a determination with high accuracy (for example, an accuracy of 75% or more).
[0036] If the second parameter is less than the second threshold value (step S105: Yes), the arc welding conditions are not changed (step S106).
[0037] On the other hand, if the absolute value of the rate of change is less than the first threshold value (step S104: No), the arc welding conditions are changed (step S107).If the second parameter is equal to or greater than the second threshold value (step S105: No), the arc welding conditions are changed (step S107).
[0038] The arc welding conditions include, for example, at least one of the current value, voltage value, and current application time in arc welding. For example, by increasing the current value (voltage value), the amount of melting of welding rod 35 can be increased, and hole 21 can be repaired. Also, for example, by extending the current application time, the amount of melting of welding rod 35 can be increased, and hole 21 can be repaired.
[0039] The arc welding conditions may also include the position of the welding rod 35 during arc welding. For example, by moving the welding rod 35 in the first direction D1 opposite to the direction of travel, the welding rod 35 can be melted near the hole 21, thereby repairing the hole 21. In other words, by moving the welding rod 35 near the hole 21, the hole 21 can be repaired. Furthermore, for example, by moving the welding rod 35 in the second direction D2 so as to approach the hole 21, the welding rod 35 can be melted near the hole 21, thereby repairing the hole 21.
[0040] The arc welding conditions may also include the moving speed of the welding rod 35. For example, by slowing down the moving speed of the welding rod 35, the welding rod 35 can be melted near the hole 21, thereby repairing the hole 21.
[0041] In the arc welding method according to the first embodiment, steps S101 to S103 correspond to the obtaining step, and in the arc welding method according to the first embodiment, steps S104 to S107 correspond to the adjusting step.
[0042] In step S105, it may be determined whether the first parameter is less than the second threshold value, or it may be determined whether both the first parameter and the second parameter are less than the second threshold value. Furthermore, step S105 is performed as needed and can be omitted. If step S105 is omitted, when the absolute value of the rate of change is equal to or greater than the first threshold value (step S104: Yes), the arc welding conditions are not changed (step S106).
[0043] As described above, in the arc welding method according to the first embodiment, if there is a large change in the state of the hole 21, it is assumed that the hole 21 will close naturally (i.e., over time), and the arc welding conditions are not changed to repair the hole 21. On the other hand, if there is a small change in the state of the hole 21, it is assumed that the hole 21 will not close naturally (i.e., even over time), and the arc welding conditions are changed to repair the hole 21. By repairing only the holes 21 that will not close naturally, rather than repairing all of the holes 21 that appear in the molten pool 20 during welding, it is possible to suppress the occurrence of hole defects while also suppressing the occurrence of problems due to repair, such as variations in quality and reduced yields.
[0044] Furthermore, by changing the arc welding conditions when the second parameter is equal to or greater than the second threshold value, even if there is a large change in the state of hole 21, if hole 21 is unlikely to close naturally (for example, if the area of hole 21 is large), the arc welding conditions are changed to repair hole 21. This makes it possible to more reliably suppress the occurrence of hole defects.
[0045] Furthermore, by using the area of the hole 21 as a parameter indicating the state of the hole 21, it becomes easier to obtain more accurate parameters from the image than when using, for example, the circularity or aspect ratio of the hole 21, and it is possible to more accurately determine whether the hole 21 will close naturally. Therefore, it is possible to more reliably repair only the holes 21 that will not close naturally.
[0046] The determination of whether or not the hole 21 will close naturally may be made using at least one of the above parameters, or may be made using a combination of two or more of the above parameters.
[0047] When calculating the rate of change based on three or more parameters, it is preferable to calculate the rate of change based on the largest value of the parameters. In other words, when calculating the rate of change from three or more parameters, it is preferable to calculate the rate of change normalized by the largest value of the parameters. For example, assume that the first parameter is "9," the second parameter is "10," the third parameter is "6," and the fourth parameter is "1." In this case, the second parameter, which has the largest value, is used as the base. The rate of change from the first parameter to the second parameter is expressed as 100 × (second parameter - first parameter) / second parameter = 10 [%]. The rate of change from the second parameter to the third parameter is expressed as 100 × (second parameter - third parameter) / second parameter = 40 [%]. The rate of change from the third parameter to the fourth parameter is expressed as 100 × (third parameter - fourth parameter) / second parameter = 50 [%]. When calculating the rate of change based on three or more parameters, for example, if at least one of the multiple rate of change is equal to or greater than a threshold, the arc welding conditions are not changed. In other words, when the rate of change is calculated based on three or more parameters, the arc welding conditions are changed, for example, when all of the multiple rate of change are less than a threshold value. Also, when the rate of change is calculated based on three or more parameters, it is preferable to calculate the rate of change from a parameter whose value decreases over time among the multiple parameters and determine whether or not to change the arc welding conditions. For example, in the example of the first to fourth parameters above, it is preferable to calculate the rate of change from the second parameter, the third parameter, and the fourth parameter, excluding the first parameter, and make the determination.
[0048] FIG. 6 is a flowchart illustrating an example of an arc welding method according to the second embodiment. 6, in the arc welding method according to the second embodiment, when welding is started, images of the welding point are successively acquired. Specifically, a first image is acquired at a first time, a second image is acquired at a second time, and a third image is acquired at a third time (step S201). The second time is a time later than the first time. The third time is a time later than the second time.
[0049] Next, a first parameter which is a parameter indicating the state of the hole 21 at a first time is acquired from the first image, a second parameter which is a parameter indicating the state of the hole 21 at a second time is acquired from the second image, and a third parameter which is a parameter indicating the state of the hole 21 at a third time is acquired from the third image (step S202). More specifically, for example, a first area which is the area of the hole 21 at the first time is acquired from the first image, a second area which is the area of the hole 21 at the second time is acquired from the second image, and a third area which is the area of the hole 21 at a third time is acquired from the third image.
[0050] Next, a first rate of change, which is the rate of change from the first parameter to the second parameter, is acquired, and a second rate of change, which is the rate of change from the second parameter to the third parameter, is acquired (step S203). More specifically, for example, a first rate of change, which is the rate of change from the first area to the second area, is acquired, and a second rate of change, which is the rate of change from the second area to the third area, is acquired.
[0051] Next, it is determined whether the absolute value of the average change rate is equal to or greater than a first threshold value (step S205). The first threshold value in the second embodiment is the same as the first threshold value in the first embodiment.
[0052] If the absolute value of the average rate of change is equal to or greater than the first threshold (step S205: Yes), it is determined whether the third parameter is less than the second threshold (step S206). The second threshold in the second embodiment is the same as the second threshold in the first embodiment.
[0053] If the third parameter is less than the second threshold value (step S206: Yes), the arc welding conditions are not changed (step S207).
[0054] On the other hand, if the absolute value of the average rate of change is less than the first threshold (step S205: No), the arc welding conditions are changed (step S208).If the third parameter is equal to or greater than the second threshold (step S206: No), the arc welding conditions are changed (step S208).
[0055] The arc welding conditions that are changed in the second embodiment are the same as the arc welding conditions that are changed in the first embodiment.
[0056] In the arc welding method according to the second embodiment, steps S201 to S204 correspond to the obtaining step, and steps S205 to S208 correspond to the adjusting step.
[0057] In step S206, it may be determined whether the first parameter is less than the second threshold value, or whether the second parameter is less than the second threshold value, or it may be determined whether two or more of the first parameter, the second parameter, and the third parameter are less than the second threshold value. Step S206 is performed as needed and can be omitted. If step S206 is omitted, when the absolute value of the average rate of change is equal to or greater than the first threshold value (step S205: Yes), the arc welding conditions are not changed (step S207).
[0058] In this way, also in the arc welding method according to the second embodiment, if there is a large change in the state of the hole 21, it is assumed that the hole 21 will close naturally (i.e., over time), and the arc welding conditions are not changed to repair the hole 21. On the other hand, if there is a small change in the state of the hole 21, it is assumed that the hole 21 will not close naturally (i.e., even over time), and the arc welding conditions are changed to repair the hole 21. By repairing only the holes 21 that will not close naturally, rather than repairing all of the holes 21 that appear in the molten pool 20 during welding, it is possible to suppress the occurrence of hole defects while also suppressing the occurrence of problems due to repair, such as quality variations and reduced yield.
[0059] Furthermore, by obtaining an average change rate, which is the average value of the first change rate from the first parameter to the second parameter and the second change rate from the second parameter to the third parameter, and adjusting the arc welding conditions based on the average change rate, the influence of outliers in the parameters can be reduced, and only holes 21 that do not close naturally can be repaired more reliably.
[0060] In this example, two change rates are calculated from parameters at three times, and the average change rate value is calculated from the two change rates. However, three or more change rates may be calculated from parameters at four or more times, and the average change rate value may be calculated from the three or more change rates.
[0061] FIG. 7 is a flowchart illustrating an example of an arc welding method according to the third embodiment. 7, in the arc welding method according to the third embodiment, when welding starts, images of the welding point are successively acquired. Specifically, a first image is acquired at a first time, a second image is acquired at a second time, and a third image is acquired at a third time (step S301). The second time is a time later than the first time. The third time is a time later than the second time.
[0062] Next, a first parameter which is a parameter indicating the state of the hole 21 at a first time is acquired from the first image, a second parameter which is a parameter indicating the state of the hole 21 at a second time is acquired from the second image, and a third parameter which is a parameter indicating the state of the hole 21 at a third time is acquired from the third image (step S302). More specifically, for example, a first area which is the area of the hole 21 at the first time is acquired from the first image, a second area which is the area of the hole 21 at the second time is acquired from the second image, and a third area which is the area of the hole 21 at a third time is acquired from the third image.
[0063] Next, the intermittent change rate, which is the rate of change from the first parameter to the third parameter, is acquired (step S303). More specifically, for example, the intermittent change rate, which is the rate of change from the first area to the third area, is acquired.
[0064] Next, it is determined whether the absolute value of the intermittent change rate is equal to or greater than a first threshold value (step S304). The first threshold value in the third embodiment is the same as the first threshold value in the first embodiment.
[0065] If the absolute value of the intermittent change rate is equal to or greater than the first threshold (step S304: Yes), it is determined whether the third parameter is less than the second threshold (step S305). The second threshold in the third embodiment is the same as the second threshold in the first embodiment.
[0066] If the third parameter is less than the second threshold value (step S305: Yes), the arc welding conditions are not changed (step S306).
[0067] On the other hand, if the absolute value of the intermittent change rate is less than the first threshold value (step S304: No), the arc welding conditions are changed (step S307).If the third parameter is equal to or greater than the second threshold value (step S305: No), the arc welding conditions are changed (step S307).
[0068] The arc welding conditions that are changed in the third embodiment are the same as the arc welding conditions that are changed in the first embodiment.
[0069] In the arc welding method according to the third embodiment, steps S301 to S303 correspond to the obtaining step, and steps S304 to S307 correspond to the adjusting step.
[0070] In step S305, it may be determined whether the first parameter is less than the second threshold value, or it may be determined whether the second parameter is less than the second threshold value, or it may be determined whether two or more of the first parameter, the second parameter, and the third parameter are less than the second threshold value. Step S305 is performed as needed and can be omitted. If step S305 is omitted, when the absolute value of the intermittent change rate is equal to or greater than the first threshold value (step S304: Yes), the arc welding conditions are not changed (step S306).
[0071] As described above, in the arc welding method according to the third embodiment, if there is a large change in the state of the hole 21, it is assumed that the hole 21 will close naturally (i.e., over time), and the arc welding conditions are not changed to repair the hole 21. On the other hand, if there is a small change in the state of the hole 21, it is assumed that the hole 21 will not close naturally (i.e., even over time), and the arc welding conditions are changed to repair the hole 21. By repairing only the holes 21 that will not close naturally, rather than repairing all of the holes 21 that appear in the molten pool 20 during welding, it is possible to suppress the occurrence of hole defects while also suppressing the occurrence of problems due to repair, such as variations in quality and reduced yield.
[0072] In addition, by adjusting the arc welding conditions based on the intermittent change rate from the first parameter to the third parameter, the influence of outliers in the parameters can be reduced, and only holes 21 that do not close naturally can be repaired more reliably.
[0073] In this example, the rate of change of every other parameter (the first parameter at the first time and the third parameter at the third time) is calculated, but the rate of change of every third parameter (the first parameter at the first time and the fourth parameter at the fourth time), or every third parameter (the first parameter at the first time and the fifth parameter at the fifth time), or every Nth parameter (N is an integer of 2 or more) may also be calculated.
[0074] FIG. 8 is a flowchart illustrating an example of an arc welding method according to the fourth embodiment. 8, in the arc welding method according to the fourth embodiment, when welding is started, images of the welding point are successively acquired. Specifically, a first image is acquired at a first time, a second image is acquired at a second time, a third image is acquired at a third time, a fourth image is acquired at a fourth time, a fifth image is acquired at a fifth time, and a sixth image is acquired at a sixth time (step S401). The second time is later than the first time. The third time is later than the second time. The fourth time is later than the first time. The fifth time is later than the fourth time. The sixth time is later than the fifth time.
[0075] The fourth to sixth times may each be later than the second time, earlier than the second time, or the same as the second time. The fourth to sixth times may each be later than the third time, earlier than the third time, or the same as the third time. In other words, the period from the fourth to sixth times may or may not overlap with the period from the first to third times.
[0076] Next, a first parameter is obtained from the first image, which is a parameter indicating the state of the hole 21 at the first time; a second parameter is obtained from the second image, which is a parameter indicating the state of the hole 21 at the second time; a third parameter is obtained from the third image, which is a parameter indicating the state of the hole 21 at the third time; a fourth parameter is obtained from the fourth image, which is a parameter indicating the state of the hole 21 at the fourth time; a fifth parameter is obtained from the fifth image, which is a parameter indicating the state of the hole 21 at the fifth time; and a sixth parameter is obtained from the sixth image, which is a parameter indicating the state of the hole 21 at the sixth time (step S402). More specifically, for example, a first area, which is the area of hole 21 at a first time, is obtained from a first image, a second area, which is the area of hole 21 at a second time, is obtained from a second image, a third area, which is the area of hole 21 at a third time, is obtained from a third image, a fourth area, which is the area of hole 21 at a fourth time, is obtained from a fourth image, a fifth area, which is the area of hole 21 at a fifth time, is obtained from a fifth image, and a sixth area, which is the area of hole 21 at a sixth time, is obtained from a sixth image.
[0077] Next, a first average value, which is the average value of the first parameter, the second parameter, and the third parameter, and a second average value, which is the average value of the fourth parameter, the fifth parameter, and the sixth parameter, are obtained (step S403). More specifically, for example, a first average value, which is the average value of the first area, the second area, and the third area, and a second average value, which is the average value of the fourth area, the fifth area, and the sixth area, are obtained. The first average value is the average value of the second time and the times before and after the second time (the first time and the third time). The second average value is the average value of the fifth time and the times before and after the fifth time (the fourth time and the sixth time).
[0078] Next, the average value change rate, which is the rate of change from the first average value to the second average value, is obtained (step S404).
[0079] Next, it is determined whether the absolute value of the average value change rate is equal to or greater than a first threshold value (step S405). The first threshold value in the fourth embodiment is the same as the first threshold value in the first embodiment.
[0080] If the absolute value of the average value change rate is equal to or greater than the first threshold (step S405: Yes), it is determined whether the sixth parameter is less than the second threshold (step S406). The second threshold in the fourth embodiment is the same as the second threshold in the first embodiment.
[0081] If the sixth parameter is less than the second threshold value (step S406: Yes), the arc welding conditions are not changed (step S407).
[0082] On the other hand, if the absolute value of the average value change rate is less than the first threshold value (step S405: No), the arc welding conditions are changed (step S408).If the sixth parameter is equal to or greater than the second threshold value (step S406: No), the arc welding conditions are changed (step S408).
[0083] The arc welding conditions that are changed in the fourth embodiment are the same as the arc welding conditions that are changed in the first embodiment.
[0084] In the arc welding method according to the fourth embodiment, steps S401 to S404 correspond to the obtaining step, and in the arc welding method according to the third embodiment, steps S405 to S408 correspond to the adjusting step.
[0085] In step S406, it may be determined whether the first parameter is less than the second threshold, whether the second parameter is less than the second threshold, whether the third parameter is less than the second threshold, whether the fourth parameter is less than the second threshold, whether the fifth parameter is less than the second threshold, or whether two or more of the first parameter, the second parameter, the third parameter, the fourth parameter, the fifth parameter, and the sixth parameter are less than the second threshold. Step S406 is performed as needed and can be omitted. If step S406 is omitted, when the absolute value of the average value change rate is equal to or greater than the first threshold (step S405: Yes), the arc welding conditions are not changed (step S407).
[0086] As described above, in the arc welding method according to the fourth embodiment, if there is a large change in the state of the hole 21, it is assumed that the hole 21 will close naturally (i.e., over time), and the arc welding conditions are not changed to repair the hole 21. On the other hand, if there is a small change in the state of the hole 21, it is assumed that the hole 21 will not close naturally (i.e., even over time), and the arc welding conditions are changed to repair the hole 21. By repairing only the holes 21 that will not close naturally, rather than repairing all of the holes 21 that appear in the molten pool 20 during welding, it is possible to suppress the occurrence of hole defects while also suppressing the occurrence of problems due to repair, such as variations in quality and reduced yield.
[0087] Furthermore, by obtaining the average value change rate, which is the rate of change from the first average value of the first to third parameters to the second average value of the fourth to sixth parameters, and adjusting the arc welding conditions based on the average value change rate, the influence of outliers in the parameters can be reduced, and only holes 21 that do not close naturally can be repaired more reliably.
[0088] In this example, the average values of the parameters at three times are calculated, but the average values of the parameters at four or more times may be calculated.
[0089] In the arc welding method according to the fourth embodiment, the first average value and the second average value are, for example, moving average values. That is, the average value change rate is, for example, the rate of change of the moving average value. In other words, the arc welding method according to the embodiment may be an arc welding method in which, in the acquisition step, parameters are continuously acquired, and a moving average value change rate that is the rate of change from the first moving average value to the second moving average value is acquired based on a first moving average value that is the moving average value of the parameters at a first time and a second moving average value that is the moving average value of the parameters at a second time after the first time, and in the adjustment step, the conditions are not changed if the absolute value of the moving average value change rate is equal to or greater than a first threshold value, and the conditions are changed if the absolute value of the moving average value change rate is less than the first threshold value.
[0090] Embodiments may include the following features.
[0091] (Configuration 1) A method for arc welding in which a first portion of a second material to be welded having a flat plate-like first portion is overlapped on a first material to be welded having a flat plate-like first portion, an acquisition step of acquiring a rate of change of a parameter indicating a state of a hole formed in a molten pool while arc welding is being performed with the second weld material overlapped on the first weld material; an adjusting step of adjusting the arc welding conditions based on the rate of change; Equipped with In the adjusting step, If the absolute value of the rate of change is equal to or greater than a first threshold, the condition is not changed, When the absolute value of the rate of change is less than the first threshold, the condition is changed.
[0092] (Configuration 2) 2. The arc welding method according to claim 1, wherein the parameter is an area of the hole.
[0093] (Configuration 3) 3. The arc welding method according to claim 2, wherein in the acquiring step, an image of the welding point is acquired, and a portion in the image whose brightness is equal to or less than a predetermined value is determined to be the hole, thereby acquiring the rate of change in the area of the hole.
[0094] (Configuration 4) 3. The arc welding method according to claim 2, wherein in the acquiring step, an image of the welding point is acquired, and the hole in the image is determined based on a model created by machine learning, thereby acquiring a rate of change in the area of the hole.
[0095] (Configuration 5) 5. The arc welding method according to any one of configurations 1 to 4, wherein the conditions include at least one of a current value, a voltage value, and a current application time in the arc welding.
[0096] (Configuration 6) 5. The arc welding method according to any one of configurations 1 to 4, wherein the conditions include a position of a welding rod in the arc welding.
[0097] (Configuration 7) 5. The arc welding method according to any one of configurations 1 to 4, wherein the conditions include a moving speed of a welding rod in the arc welding.
[0098] (Configuration 8) 8. The arc welding method according to any one of configurations 1 to 7, wherein, in the adjustment step, if the absolute value of the rate of change is equal to or greater than the first threshold value and the parameter is less than a second threshold value, the condition is not changed, and if the absolute value of the rate of change is equal to or greater than the first threshold value and the parameter is equal to or greater than a second threshold value, the condition is changed.
[0099] (Configuration 9) In the acquiring step, the parameters are continuously acquired, and a first change rate which is a change rate from the first parameter to the second parameter and a second change rate which is a change rate from the second parameter to the third parameter are acquired based on a first parameter which is the parameter at a first time, a second parameter which is the parameter at a second time after the first time, and a third parameter which is the parameter at a third time after the second time, and an average change rate value which is an average value of the first change rate and the second change rate is acquired; In the adjusting step, If the absolute value of the average rate of change is equal to or greater than the first threshold value, the condition is not changed, 9. The arc welding method according to any one of configurations 1 to 8, wherein the condition is changed when the absolute value of the average rate of change is less than the first threshold value.
[0100] (Configuration 10) In the acquiring step, the parameters are continuously acquired, and an intermittent change rate, which is a rate of change from the first parameter to the third parameter, is acquired based on a first parameter that is the parameter at a first time, a second parameter that is the parameter at a second time after the first time, and a third parameter that is the parameter at a third time after the second time; In the adjusting step, If the absolute value of the intermittent change rate is equal to or greater than the first threshold value, the condition is not changed, 9. The arc welding method according to any one of configurations 1 to 8, wherein the condition is changed when the absolute value of the intermittent change rate is less than the first threshold value.
[0101] (Configuration 11) In the acquiring step, the parameters are continuously acquired, and a first average value which is an average value of the first parameter, the second parameter, and the third parameter, and a second average value which is an average value of the fourth parameter, the fifth parameter, and the sixth parameter, are acquired based on a first parameter which is the parameter at a first time, a second parameter which is the parameter at a second time later than the first time, a third parameter which is the parameter at a third time later than the second time, a fourth parameter which is the parameter at a fourth time later than the first time, a fifth parameter which is the parameter at a fifth time later than the fourth time, and a sixth parameter which is the parameter at a sixth time later than the fifth time, and an average value change rate which is a rate of change from the first average value to the second average value; In the adjusting step, If the absolute value of the average value change rate is equal to or greater than the first threshold value, the condition is not changed, 9. The arc welding method according to any one of configurations 1 to 8, wherein the condition is changed when the absolute value of the average value change rate is less than the first threshold value.
[0102] As described above, according to the embodiment, it is possible to provide an arc welding method that can suppress the occurrence of hole defects and the occurrence of problems due to repair.
[0103] While the present invention has been described above by way of example, it is not intended to limit the scope of the present invention. This novel embodiment may be embodied in various other forms, and various omissions, substitutions, modifications, etc. may be made without departing from the spirit of the invention. This embodiment and its modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the claims and their equivalents. [Explanation of symbols]
[0104] 11: First welding material 12: Second welding material 12a: 1st part 12b:Second part 20: Molten pool 21: Hole 30: Torch 31: Electrode 35: Welding rod 40: Camera
Claims
1. A method for arc welding in which a second material to be welded, having a flat plate-shaped first portion, is overlapped with the first portion of the second material to be welded, the method comprising: an acquisition step of acquiring a rate of change of a parameter indicating a state of a hole formed in a molten pool while arc welding is being performed with the second weld material overlapped on the first weld material; an adjusting step of adjusting the arc welding conditions based on the rate of change; Equipped with In the adjusting step, If the absolute value of the rate of change is equal to or greater than a first threshold, the condition is not changed, When the absolute value of the rate of change is less than the first threshold, the condition is changed.
2. The arc welding method of claim 1 , wherein the parameter is an area of the hole.
3. 3. The arc welding method according to claim 2, wherein the acquiring step acquires an image of the welded portion, and determines a portion of the image whose brightness is equal to or less than a predetermined value as the hole, thereby acquiring the rate of change in the area of the hole.
4. 3. The arc welding method according to claim 2, wherein the acquisition step acquires an image of the welded portion, and determines the hole in the image based on a model created by machine learning, thereby acquiring a rate of change in the area of the hole.
5. The arc welding method according to claim 1 , wherein the conditions include at least one of a current value, a voltage value, and a welding time in the arc welding.
6. The arc welding method according to claim 1 , wherein the conditions include a position of a welding rod in the arc welding.
7. The arc welding method according to claim 1 , wherein the conditions include a moving speed of a welding rod in the arc welding.
8. In the adjusting step, If the absolute value of the rate of change is equal to or greater than the first threshold value and if the parameter is less than a second threshold value, the condition is not changed; The arc welding method according to claim 1 , wherein the condition is changed when the absolute value of the rate of change is equal to or greater than the first threshold value and when the parameter is equal to or greater than a second threshold value.
9. In the acquiring step, the parameters are continuously acquired, and a first change rate which is a change rate from the first parameter to the second parameter and a second change rate which is a change rate from the second parameter to the third parameter are acquired based on a first parameter which is the parameter at a first time, a second parameter which is the parameter at a second time after the first time, and a third parameter which is the parameter at a third time after the second time, and an average change rate value which is an average value of the first change rate and the second change rate is acquired; In the adjusting step, If the absolute value of the average rate of change is equal to or greater than the first threshold value, the condition is not changed, 9. The arc welding method according to claim 1, wherein the condition is changed when the absolute value of the average rate of change is less than the first threshold value.
10. In the acquiring step, the parameters are continuously acquired, and an intermittent change rate, which is a rate of change from the first parameter to the third parameter, is acquired based on a first parameter that is the parameter at a first time, a second parameter that is the parameter at a second time after the first time, and a third parameter that is the parameter at a third time after the second time; In the adjusting step, If the absolute value of the intermittent change rate is equal to or greater than the first threshold value, the condition is not changed, 9. The arc welding method according to claim 1, wherein the condition is changed when the absolute value of the intermittent change rate is less than the first threshold value.
11. In the acquiring step, the parameters are continuously acquired, and a first average value which is an average value of the first parameter, the second parameter, and the third parameter, and a second average value which is an average value of the fourth parameter, the fifth parameter, and the sixth parameter, are acquired based on a first parameter which is the parameter at a first time, a second parameter which is the parameter at a second time after the first time, a third parameter which is the parameter at a third time after the second time, a fourth parameter which is the parameter at a fourth time after the first time, a fifth parameter which is the parameter at a fifth time after the fourth time, and a sixth parameter which is the parameter at a sixth time after the fifth time, and an average value change rate which is a rate of change from the first average value to the second average value, In the adjusting step, If the absolute value of the average value change rate is equal to or greater than the first threshold value, the condition is not changed, 9. The arc welding method according to claim 1, wherein the condition is changed when the absolute value of the average value change rate is less than the first threshold value.
Citation Information
Patent Citations
Processing device, welding system, processing method, program, and storage medium
JP2022105404A