Electroslag welding device, method for controlling electroslag welding device, and program

Abstract

The invention provides an electroslag welding device, a method for controlling the electroslag welding device, and a program, wherein the influence related to the installation accuracy of the device is suppressed in electroslag welding and the convenience of a user is improved. This electroslag welding device is provided with: a welding torch for performing electroslag welding; an imaging device which is configured to be capable of imaging a molten welding slag bath in a groove formed by a base material; a specifying means for specifying the region of the molten slag bath from the image captured by the imaging device; and an adjustment mechanism that adjusts the position of the tip of the welding torch in the first direction on the basis of the difference in the first direction between the position of the region determined by the determination mechanism and the position of the tip of the welding torch in the groove.

Description

Technical Field

[0001] The present invention relates to an electroslag welding device, a control method and a program for the electroslag welding device. Background Art

[0002] In the manufacture of structures in the fields of shipbuilding and reinforced construction, vertical welding is performed. In this vertical welding, for example, electroslag welding (ESW) using the Joule heat of molten slag as a heat source is used, and automation is being promoted. Electroslag welding generates heat in the molten slag to melt the welding wire and the base material, so no arc radiation heat is generated. In addition, less smoke and spatter are generated, which is suitable for improving the working environment. In addition, since the weld metal is shielded from the atmosphere in the molten slag, there is no need for a shielding gas, and the protection effect does not deteriorate even if the plate thickness increases. It is possible to effectively prevent nitrogen and the like present in the atmosphere from invading the molten metal regardless of the plate thickness. Therefore, the mechanical properties of the weld metal are good.

[0003] In vertical welding such as electroslag welding, for example, Patent Document 1 discloses a structure in which the depth of a slag bath is maintained at a state suitable for welding without providing a detector for detecting the slag bath.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6460910

[0007] In vertical welding, the device welds while ascending along the groove of the welding object, that is, along a track set parallel to the ascending direction. At this time, it is sought to accurately set the track that will become the moving path of the device in parallel, but it is difficult to set it manually, and it may cause deviation in the left and right directions. In vertical welding, it is necessary to maintain the welding torch and copper plate in the center of the groove, and adjust them manually in the event of deviation. In order to solve such a problem, for example, as a structure for automatically welding while correcting the deviation, it is considered to use a mechanical imitation device obtained by inserting a roller into the groove of the groove. However, in such a structure, there are problems such as high cost, large degree of error, and restrictions on the handling of the groove width. Summary of the invention

[0008] Problems to be solved by the invention

[0009] In the present invention, based on the above-mentioned problems, an object of the present invention is to suppress the influence of the installation accuracy of the device in electroslag welding and to improve the convenience for the user.

[0010] Solutions to Solve Problems

[0011] In order to solve the above problems, the present invention has the following structure. That is, the electroslag welding device has:

[0012] A welding torch for performing electroslag welding;

[0013] a photographing device configured to photograph a molten slag bath within a groove formed by a base material;

[0014] a determining mechanism that determines the area of ​​the molten slag bath from the image captured by the capturing device; and

[0015] An adjustment mechanism adjusts the position of the tip of the welding torch in the first direction based on a difference in the first direction between the position of the area determined by the determination mechanism and the position of the tip of the welding torch in the groove.

[0016] In addition, another embodiment of the present invention has the following structure. That is, the control method of the electroslag welding device has:

[0017] an acquisition step of acquiring an image captured by an imaging device configured to capture a molten slag bath in a groove formed by a base material;

[0018] a determining step of determining a region of the molten slag bath from the image; and

[0019] The adjusting step adjusts the position of the tip of the welding torch in the first direction based on the difference in the first direction between the position of the area determined in the determining step and the position of the tip of the welding torch in the groove.

[0020] In addition, another embodiment of the present invention has the following structure. That is, the program causes the computer to execute the following steps:

[0021] an acquisition step of acquiring an image captured by an imaging device configured to capture a molten slag bath in a groove formed by a base material;

[0022] a determining step of determining a region of the molten slag bath from the image; and

[0023] The adjusting step adjusts the position of the tip of the welding torch in the first direction based on the difference in the first direction between the position of the area determined in the determining step and the position of the tip of the welding torch in the groove.

[0024] Effects of the Invention

[0025] According to the present invention, in electroslag welding, the influence associated with the installation accuracy of the device can be suppressed, and the convenience for the user can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1This is a schematic diagram showing a configuration example of a welding system according to an embodiment of the present invention.

[0027] Figure 2 This is a block diagram showing an example of the functional configuration of a welding system according to one embodiment of the present invention.

[0028] Figure 3A It is a schematic diagram showing a structural example of a groove according to one embodiment of the present invention.

[0029] Figure 3B It is a schematic diagram showing a structural example of a groove according to one embodiment of the present invention.

[0030] Figure 3C It is a schematic diagram showing a structural example of a groove according to one embodiment of the present invention.

[0031] Figure 4 This is an illustration showing an example of an image according to one embodiment of the present invention.

[0032] Figure 5A This is an example diagram for explaining image processing according to one embodiment of the present invention.

[0033] Figure 5B This is an example diagram for explaining image processing according to one embodiment of the present invention.

[0034] Figure 5C This is an example diagram for explaining image processing according to one embodiment of the present invention.

[0035] Fig. 6A This is an illustration showing an example of an image according to one embodiment of the present invention.

[0036] Figure 6B This is an illustration showing an example of an image according to one embodiment of the present invention.

[0037] Figure 6C This is an illustration showing an example of an image according to one embodiment of the present invention.

[0038] Fig.6D This is an illustration showing an example of an image according to one embodiment of the present invention.

[0039] Figure 7 This is a graph for explaining control timing according to one embodiment of the present invention.

[0040] Figure 8 This is a graph for explaining control timing according to one embodiment of the present invention.

[0041] Fig. 9 This is a flowchart of a control process according to one embodiment of the present invention.

[0042] Description of Reference Numerals

[0043] 1 Copper plate

[0044] 3. Base material

[0045] 4 welding torch

[0046] 5Conductive nozzle

[0047] 6. Welding wire

[0048] 7 Molten Slag Bath

[0049] 8. Welding current

[0050] 9 Molten Metal

[0051] 10 Weld Metal

[0052] 11 Solidified welding slag

[0053] 12. Flux

[0054] 13 Sliding copper pressure plate for welding (copper pressure plate)

[0055] 14Flux supply device

[0056] 15Welding control device

[0057] 16 Traveling trolley

[0058] 17 Traveling trolley control device

[0059] 18 Filming Devices

[0060] 19 Display device

[0061] 100 Welding device (electroslag welding device). DETAILED DESCRIPTION

[0062] Hereinafter, the present specific embodiment will be described with reference to the accompanying drawings, etc. It should be noted that the embodiment described below is used to illustrate an embodiment of the present invention, and is not intended to limit the interpretation of the present invention. In addition, the structures described in each embodiment may not all be structures necessary to solve the problems of the present invention. In addition, in each of the accompanying drawings, the same constituent elements are indicated by marking the same reference numerals to show the corresponding relationship.

[0063] <First embodiment>

[0064] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0065] [Welding system]

[0066] Figure 1 1 is a schematic diagram showing a configuration example of an electroslag welding device 100 (hereinafter referred to as welding device 100) according to the present embodiment. Figure 1 Although omitted in the figure, the welding device 100 is configured to include a welding power source, a welding wire feeding device, and an operation box which are not shown. Each part can be connected via various cables such as a power cable and a signal cable. Figure 1 : shows a coordinate system consisting of three axes: X-axis, Y-axis, and Z-axis. The X-axis is the plate thickness direction of the base material 3, the Y-axis is the direction in which a pair of base materials are arranged, that is, the horizontal direction along the surface of the base material 3, and the Z-axis is the direction along the welding line of the base material 3, that is, the up-down direction.

[0067] like Figure 1 As shown, the welding device 100 of this embodiment includes a fixed copper pressure plate 1, a sliding copper pressure plate 13 for welding (hereinafter also referred to as the copper pressure plate 13), a welding torch 4, a flux supply device 14, a welding control device 15, a traveling trolley 16, a traveling trolley control device 17, a shooting device 18 and a display device 19.

[0068] In the welding device 100, a fixed copper pressing plate 1 is arranged on the back side of the groove of a pair of base materials 3 as steel plates, and a copper pressing plate 13 as a sliding plate is arranged on the surface side of the groove. Here, a backing member made of heat-resistant ceramic can be used instead of the copper pressing plate 1 on the back side. In addition, the copper pressing plate 13 on the surface side is a copper pressing plate that slides in the up and down direction, for example, by water cooling. It should be noted that in the present embodiment, copper is cited as the material of the copper pressing plate 13, but it is not limited to copper. As long as it is a material with good thermal conductivity, the material used for the pressing plate is not particularly limited. In the present embodiment, for convenience, the side where the fixed copper pressing plate 1 is arranged is set as the "back side of the groove" or "the inner side of the groove", and the side where the copper pressing plate 13 is arranged is set as the "surface side of the groove" or "the front side of the groove", but the copper pressing plate 13 can also be arranged on both sides of the groove.

[0069] The copper pressing plate 13 is configured to be movable upward, i.e., in the Z-axis direction, by the traveling carriage 16, and also to be movable leftward, i.e., in the Y-axis direction, by the control described later. The copper pressing plate 13 is set to press against the base material 3 with a predetermined force in the X-axis direction before welding. Figure 1 Although not shown in the figure, a slag detection terminal for detecting the surface (upper surface) of the molten slag bath 7 may be provided on the upper part of the copper pressing plate 13 .

[0070] The welding torch 4 supplies power to the welding wire 6 by welding current 8 supplied from the welding power source 200 to weld the base material 3. The welding torch 4 also includes a contact tip 5 for guiding the welding wire 6 and supplying the welding current 8 to the welding wire 6.

[0071] In the groove surrounded by the base material 3, the copper pressing plate 1 and the copper pressing plate 13, the welding wire 6 is fed from the front end of the conductive tip 5 of the welding torch 4 and fed into the molten slag bath 7 formed in the groove. The welding current 8 flows from the welding wire 6 through the molten slag bath 7 to the molten metal 9. At this time, Joule heat is generated by the welding current 8 flowing in the molten slag bath 7 and the resistance of the molten slag bath 7, and welding progresses while the welding wire 6 and the base material 3 are melted.

[0072] The welding sliding copper platen 13 moves upward along the surface of the groove as the vertical welding progresses. The flux supply device 14 supplies the flux 12 by spreading the flux 12 to the molten slag bath 7. The flux 12 melts to become molten slag, so the amount, that is, the depth of the molten slag bath 7 increases by supplying the flux 12.

[0073] The flux supply device 14 adjusts the supply amount and timing of the flux 12 supplied to the molten slag bath 7 based on the instruction of the welding control device 15. The control of the timing of supplying the flux 12 and the like will be described later.

[0074] As vertical welding progresses, the molten metal 9 is cooled to become the weld metal 10, and a portion of the molten slag bath 7 becomes a molten slag layer formed between the copper platen 1 and the weld metal 10 and between the copper platen 13 and the weld metal 10. The molten slag layer cools to become solidified slag 11. In this way, a portion of the molten slag bath 7 becomes solidified slag 11 covering the weld bead surface, and is consumed as welding progresses, and the depth Ls of the molten slag bath 7 gradually decreases. In order to compensate for the reduction of the molten slag bath 7, the flux 12 that melts to become the molten slag bath 7 is additionally supplied.

[0075] The amount of solidified slag 11 covering the surface of the weld bead varies depending on the width of the weld bead and the width of the weld groove. In addition, the amount of solidified slag 11 also varies depending on the degree of close contact between the copper platen 1, copper platen 13 and the base material 3, and the cooling state of the copper platen 1, copper platen 13. Therefore, the amount of solidified slag 11 is not constant, and in order to keep the depth Ls of the molten slag bath 7 constant, it is necessary to change the amount of flux 12 supplied. The constant here is not limited to the case where the depth Ls of the molten slag bath 7 is always a value, and also includes the case where the depth Ls of the molten slag bath 7 shows a value within a constant range in consideration of the error. That is, the depth Ls of the molten slag bath 7 is controlled in a manner to maintain it within a predetermined depth range.

[0076] Here, the wire length Ld (hereinafter referred to as the dry stick-out length Ld) is defined as the distance from the front end of the contact tip 5 to the upper surface of the molten slag bath 7. This is based on the premise that the front end of the contact tip 5 is usually the position where the welding wire 6 and the contact tip 5 are energized. For example, when the front end of the contact tip 5 is protected by ceramic or the like, and the energized portion between the welding wire 6 and the contact tip 5 is provided above the front end of the contact tip 5, the position of the energized portion becomes the reference for determining the dry stick-out length Ld.

[0077] The traveling carriage 16 is equipped with a welding torch 4, a sliding copper platen 13 for welding, a flux supply device 14, a welding control device 15, a traveling carriage control device 17, and a camera 18. The traveling carriage 16 moves upward, that is, in the Z-axis direction, on a track not shown in the figure while welding, so as to raise and lower the welding device 100. That is, the traveling carriage 16 moves as a whole with the welding torch 4, the sliding copper platen 13 for welding, the flux supply device 14, the welding control device 15, the traveling carriage control device 17, and the camera 18, so that the relative positional relationship of each does not change. As the traveling carriage 16 rises, vertical welding is performed along the Z-axis direction. The track not shown in the figure is set along the welding direction around the base material 3 by manual labor before the start of welding.

[0078] The welding control device 15 controls various functions in addition to the image processing of the present embodiment. The traveling carriage control device 17 increases or decreases the traveling speed of the traveling carriage 16 based on the instruction of the welding control device 15, thereby controlling the movement of the traveling carriage 16. Figure 1 In the example of FIG. 1 , the welding control device 15 and the traveling carriage control device 17 are configured as a single structure, but they may be integrated into a single control device.

[0079] The imaging device 18 is arranged above the molten slag bath 7 in the Z-axis direction so as to be able to image the region of the molten slag bath 7 during welding. Figure 1 Where Lc represents the distance between the surface of the molten slag bath 7 in the Z-axis direction and the lens position of the camera 18. During welding, the positional relationship between the camera 18 and the traveling carriage 16 is set constant. The installation position of the camera 18 is not particularly limited, and for example, it can be arranged at the upper part of the groove formed by the base material 3, and configured as Ls = 30 cm. In addition, the camera 18 is provided with, for example, an ND (density) filter, and is configured to dim the light generated during welding to a constant degree (for example, dim 1 / 8) to obtain an image.

[0080] The display device 19 displays, for example, an image captured by the camera 18 and the results of various image processing described later. The display device 19 and the welding device 100 may be connected in a wired manner or wirelessly via an external interface not shown. In addition, it may be configured to be able to communicate with an external device other than the display device 19 via an external interface not shown. In this case, it may be configured to transmit the image captured by the camera 18 and the image obtained by performing various processing described later to the external device.

[0081] The various control devices provided in the traveling vehicle 16 are composed of a processing unit and a storage unit. The processing unit may be composed of, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a DSP (Digital Single Processor), or a dedicated circuit. In addition, the storage unit may be composed of, for example, a volatile or non-volatile memory such as an HDD (Hard Disk Drive), a ROM (Read Only Memory), or a RAM (Random Access Memory). The processing unit implements various control processes by executing a computer program for power supply control stored in the storage unit.

[0082] (Functional Structure)

[0083] Figure 2 1 is a block diagram showing an example of the functional configuration of welding control device 15 according to the present embodiment. Welding control device 15 includes image acquisition unit 201 , image processing unit 202 , image analysis unit 203 , welding control unit 204 , flux spreading control unit 205 , and output control unit 206 .

[0084] The image acquisition unit 201 acquires an image captured by the image capture device 18. The image acquisition unit 201 may also control the timing and the like related to the image capture by the image capture device 18. The image processing unit 202 applies various image processing to the image acquired by the image acquisition unit 201. The types of image processing are not particularly limited, but may include, for example, filtering processing, blurring processing, binarization processing, region extraction processing, filling processing, and the like.

[0085] The image analysis unit 203 uses the image acquired by the image acquisition unit 201 and the image processed by the image processing unit 202 to analyze the area and state included in the image. The welding control unit 204 controls each part of the welding device 100 based on the analysis result analyzed by the image analysis unit 203. For example, the welding control unit 204 issues an instruction to the traveling carriage control device 17 or performs oscillation control of the welding torch 4. A specific example of the oscillation action of this embodiment will be described later, but the oscillation action refers to an action of swinging the welding torch 4 in a predetermined direction.

[0086] The flux spreading control unit 205 controls the timing and amount of flux spreading by the flux supply device 14 based on the analysis result analyzed by the image analysis unit 203. The output control unit 206 displays the image captured by the image acquisition unit 201 on the display device 19 or outputs various messages related to welding.

[0087] [Example of groove]

[0088] Figure 3A to Figure 3C An example of a groove formed in a base material welded by the welding device 100 according to the present embodiment is shown. Figure 3A to Figure 3C This is a schematic diagram viewed from the upper side along the Z-axis direction, that is, from the direction photographed by the photographing device 18. Figure 3A to Figure 3C Although omitted in the figure, the welding device 100 is arranged on the side of the sliding copper pressing plate 13 for welding.

[0089] Figure 3A The example of V-shaped groove G is shown. The groove G is surrounded by base materials 3a and 3b arranged along the Y-axis direction, and copper platen 1 and welding sliding copper platen 13 arranged along the X-axis direction. The examples shown in the following images all show V-shaped examples. Figure 3B An example of an I-type groove G is shown. Figure 3C An example of a "レ"-shaped groove G is shown.

[0090] [Image example]

[0091] Figure 4: is a diagram showing an example of an image processed in the present embodiment. It should be noted that, in the three-dimensional coordinate system shown in the following image, the setting of the coordinates in the image and the origin is not particularly limited, and the corresponding position can be determined in the image and between images. In addition, the coordinate system of the welding device 100 and the coordinate system of the imaging device 18 can be transformed to establish a corresponding relationship. Therefore, they can establish a corresponding relationship in an absolute coordinate system or in a relative coordinate system. Therefore, the coordinates determined based on the image captured by the imaging device 18 are constituted to be able to be reflected as parameters during the action control of the welding device 100. In addition, the image captured by the imaging device 18 can be obtained in a manner that at least the groove, that is, the area of ​​the molten slag bath 7 is included near the center, and its viewing angle, image size, etc. are not particularly limited. As described above, the imaging device 18 is set before the start of welding.

[0092] Figure 4 The image 400 is an image captured by the camera 18 from the upper side along the Z-axis direction. In the image 400, a bright area Rt corresponding to the molten slag bath 7 and a dark area Ro as a peripheral area of ​​the bright area are formed. As described above, the base materials 3a, 3b, the copper platen 1, and the sliding copper platen 13 for welding are located around the molten slag bath 7. In addition, the welding torch 4 is included in the image 400. Point Cb represents the center of gravity of the area closer to the copper platen 1 side (the inner side of the groove) than the center in the X-axis direction in the groove area Rt. In addition, point Ct represents the front end position of the welding torch 4.

[0093] Figure 5A An example of an original image 500 captured by the imaging device 18 is shown. Figure 5B Show Figure 5A FIG. 5 is an example of an image 510 obtained by applying the binarization process to the image 500. The image 510 is divided into a bright area having a brightness not less than a predetermined threshold value, that is, an area 511 corresponding to the molten slag bath 7 and other areas 512 by the binarization process.

[0094] Figure 5C1 is an example of calculating the point Cb of the region Rt corresponding to the molten slag bath 7 based on the image 500 and the image 510. The point Cb shows the center of gravity position of the region from the center of the groove along the X-axis direction to the copper platen 1 side in the region Rt. In the present embodiment, the center of gravity point is derived by focusing on the prescribed range in the X-axis direction in the region Rt. Here, as a prescribed range, an example of deriving the point Cb by taking the inner half of the region Rt as the object is shown. The shadow of the welding torch 4 and the cutting of the copper platen 13 exist on the copper platen 13 side, that is, the front side of the molten slag bath 7. Due to the accumulation of flux and the inclination of the welding torch 4, these factors may reduce the accuracy of coordinate detection. Therefore, in the present embodiment, such an area is removed and the center of gravity point is derived. It should be noted that the above-mentioned prescribed range is not particularly limited. For example, the range of the area for deriving the center of gravity point can be specified according to the viewing angle of the camera 18, the shooting direction, etc.

[0095] Fig. 6A This is an example of an image 600 showing a case where the welding torch 4 has moved to the back side in the X-axis direction, that is, to the copper platen 1 side, due to the oscillation operation. Figure 6B 610 is an example of an image 610 showing a case where the welding torch 4 moves to the front side in the X-axis direction, i.e., the copper platen 13 side, due to the oscillating motion. In the present embodiment, the welding torch 4 performs an oscillating motion along the X-axis direction, i.e., the front-to-back direction of the welding device 100. The oscillation width in the front-to-back direction during the oscillating motion varies according to the thickness of the base material 3. Fig. 6A The image 600 with Figure 6B When compared with the image 610 of FIG. 1 , the range of the region Rt corresponding to the molten slag bath 7 extracted from the image is different. In particular, the image 600 in which the welding torch 4 is located on the front side in the X-axis direction can detect a larger region Rt.

[0096] Figure 6C is an example of an image 620 showing the state immediately after flux is applied to the groove. Figure 5A The image 500 with Figure 6C When compared with the image 620 of FIG. 1 , immediately after the flux is spread, the brightness of the image, more specifically, the periphery of the molten slag bath 7 decreases. Therefore, in the image immediately after the flux is spread, the accuracy of extraction of the region corresponding to the molten slag bath 7 decreases.

[0097] Fig.6DAn example of an image 630 is shown in which the tip of the welding torch 4, i.e., the welding wire 6, and the surface of the molten slag bath 7 are exposed and the arc is visually confirmed (hereinafter referred to as "open arc"). As shown in the image 630, the state in which the open arc is generated is the state in which the depth of the molten slag bath 7 is insufficient. When the open arc is generated, a smoke-like area 631 is generated. The predetermined pixel values ​​of the area 631, specifically the ratio of blue (B) and green (G) are high, so by determining their pixel values, the generation of the open arc can be captured. In other words, the area corresponding to the molten slag bath 7 is extracted from the image when the open arc is generated. As the threshold value for the pixel value used for the judgment of the open arc, for example, the upper limit and lower limit of (B, R, G) = (140, 0, 100) to (255, 220, 245) can be used. Here, an example is shown in which the three colors of B (blue), R (red), and G (green) are represented by 8 bits in each pixel.

[0098] [Action example]

[0099] In this embodiment, the position of the front end of the welding torch 4 in the left-right direction, that is, in the Y-axis direction, is adjusted using the above-mentioned image. In addition, the welding torch 4 is assumed to oscillate along the X-axis direction. Figure 4 As shown, in this embodiment, it is possible to determine the coordinates of the point Cb corresponding to the center of gravity of the molten slag bath 7 and the point Ct corresponding to the tip position of the welding torch 4. When the positions (coordinates) of these points in the Y-axis direction are offset, the left-right direction position of the tip position of the welding torch 4 is adjusted.

[0100] In addition, if Fig. 6A as well as Figure 6B As shown, the range of the area corresponding to the molten slag bath 7 observed from the imaging device 18 is different due to the oscillating action of the welding torch 4. Therefore, in this embodiment, an image of the case where the tip of the welding torch 4 is located on the front side is used to capture the range of the area corresponding to the molten slag bath 7 as wide as possible.

[0101] In addition, if Figure 6C As shown, immediately after the flux is spread, the extraction accuracy of the region corresponding to the molten slag bath 7 from the image observed by the imaging device 18 decreases. Therefore, in this embodiment, in order to further improve the extraction accuracy of the region corresponding to the molten slag bath 7, images within a certain period of time from the flux spreading are not used.

[0102] Figure 7 2 is a diagram for explaining the change in the X-axis direction of the region corresponding to the molten slag bath 7 determined from the image. Figure 7In FIG. 7 , the horizontal axis represents time [seconds] and the vertical axis represents the coordinates [pixels] in the X-axis direction. Curve 701 shows the center of gravity position of the region corresponding to the molten slag bath 7 determined from the image captured by the imaging device 18, i.e., Figure 4 The coordinate of the point Cb in the X-axis direction. Curve 702 shows the timing of spreading the flux. In the curve 702, the timing of spreading the flux becomes the position of the peak.

[0103] Referring to the curves 701 and 702, it can be seen that the coordinates of the point Cb change immediately after the flux is spread. That is, immediately after the flux is spread, there is a concern that a position different from the coordinates of the original point Cb may be detected, and the detection accuracy may be reduced. Therefore, in order to further improve the extraction accuracy of the region corresponding to the molten slag bath 7, images within a certain period of time from the flux spreading are not used.

[0104] In addition, if Fig.6D As shown, when a bright arc occurs, the extraction accuracy of the region corresponding to the molten slag bath 7 from the image observed by the imaging device 18 decreases. Therefore, in this embodiment, in order to further improve the extraction accuracy of the region corresponding to the molten slag bath 7, the image in which a bright arc occurs is not used.

[0105] Figure 8 This is a graph showing a control example in which welding is performed along a track that is set to be offset 9 mm to the left in the Y-axis direction between the initial position and the final position during electroslag welding. That is, it is more preferable that the track (not shown) that is the moving path of the welding device 100 is set parallel to the groove direction without offset. However, such an arrangement is difficult in reality, and therefore the setting position of the track at the start position and the end position of welding may be offset.

[0106] exist Figure 8 In the figure, the horizontal axis represents the passage of time [seconds], and the vertical axis represents the relative position [mm] to the left and right of the start position of welding. In this embodiment, the left and right here correspond to the Y-axis direction. In addition, in the Y-axis direction, the left direction is set as positive, and the right direction is set as negative. Figure 8 In the example, the upward direction of the vertical axis corresponds to the positive (left direction).

[0107] The dotted line 801 shows the center position of the assumed molten slag bath 7. As described above, when the start position is set to 0, the end position is offset to the left by 9 mm. The threshold value Th1 and the threshold value Thr are threshold values ​​for correcting the tip position of the welding torch 4. The threshold value Th1 is a threshold value for the offset to the left, and the threshold value Thr is a threshold value for the offset to the right. Each threshold value can be determined according to the accuracy of welding, and is set to be predetermined and stored in a storage unit or the like.

[0108] Curve 802 shows the position of the welding torch 4 relative to the Y-axis (left-right) direction. Curve 803 shows the position of the copper platen 13 relative to the Y-axis (left-right) direction. It should be noted that the welding torch 4 and the copper platen 13 can be configured to perform the same action synchronously in the Y-axis direction, or can be configured to be able to adjust their positions separately. Curve 804 shows the position of the molten slag bath 7 relative to the Y-axis (left-right) direction determined based on the image obtained by the camera 18. Figure 4 As shown in FIG. 1 and FIG. 2 , the position of the point Cb which is the center of gravity of the molten slag bath 7 will be described.

[0109] In this embodiment, when the position of the point Cb of the molten slag bath 7 shown by the curve 804 exceeds the threshold value, that is, when it deviates in the left-right direction by more than the threshold value, the positions of the welding torch 4 and the copper platen 13 are corrected. Figure 8 In the example of , the positions of the welding torch 4 and the copper platen 13 are adjusted to the left when a deviation above the threshold occurs around 190 seconds, 250 seconds, 290 seconds, 380 seconds, 510 seconds, 620 seconds, and 660 seconds from the start time. Figure 8 In the example shown, the value from the start of welding to about 100 seconds is merely the effect of the beginning of welding and is not considered here.

[0110] [Processing Flow]

[0111] Fig. 9 The flowchart of the control process of this embodiment is shown. This process flow is realized by, for example, a processing unit provided in the welding device 100 reading out and executing a corresponding program from a storage unit. This process flow is executed when the welding device 100 is set to the base material 3 to be welded. Here, in order to simplify the description, the processing subject is generally described as the welding device 100.

[0112] In S901, the welding device 100 starts welding. The start here may be in accordance with the user's instructions, or may be started when a predetermined condition is satisfied. The welding here also includes the rising action of the welding device 100 and the feeding of the welding wire 6 by the control of the traveling carriage 16.

[0113] In S902, the welding device 100 starts imaging the molten slag bath 7 by the imaging device 18. Figure 4 The image shown.

[0114] In S903, welding device 100 starts the copy control of welding torch 4. In the present embodiment, the copy control is performed by causing welding torch 4 to oscillate along the X-axis direction.

[0115] In S904, the welding device 100 analyzes the images captured by the imaging device 18 in sequence. The analysis here may be performed at a predetermined frame rate. During the analysis, the image may be subjected to image processing such as filtering, blurring, binarization, region extraction, and filling. The image processing is performed in parallel with the welding operation, so it is preferable to set the processing load to a level that can achieve a certain degree of responsiveness.

[0116] In S905, the welding device 100 determines whether the image analysis performed in S904 has detected the occurrence of a bright arc. Fig.6D As shown in FIG. 1 , when a bright arc is generated, an area having a predetermined pixel value is generated, so it can be determined based on the pixel value of each pixel included in the image. When the generation of a bright arc is detected (Yes in S905), the process of the welding device 100 proceeds to S906. On the other hand, when the generation of a bright arc is not detected (No in S905), the process of the welding device 100 proceeds to S908.

[0117] In S906, the welding device 100 performs flux spreading. The amount of flux spread here can be predetermined. In addition, the flux spreading can be performed in a predetermined amount at once, or can be performed in stages. In addition, when spreading the flux, the welding device 100 can also stop other actions such as the rising action. In addition, along with the detection of the bright arc in S905, the welding device 100 can also display the generation of the bright arc on the display device 19 in addition to the spreading of the flux.

[0118] In S907, the welding device 100 waits for a predetermined time. That is, it waits until the flux spread in S906 melts and no open arc is generated. The waiting time here can also be predetermined according to the amount of flux spread. After that, the processing of the welding device 100 returns to S904 and the processing is repeated.

[0119] In S908, the welding device 100 determines whether the front end of the welding torch 4 is located at a predetermined position. The welding torch 4 performs an oscillating motion along the X-axis direction. Fig. 6A as well as Figure 6BAs described above, the accuracy of determining the center of gravity position of the molten slag bath 7 varies according to the position of the welding torch 4. Therefore, in the present embodiment, the situation where the front end of the welding torch 4 is located on the front side is taken as the prescribed position to make the determination accuracy of the center of gravity position higher. It should be noted that the prescribed position may also be the situation where the front end of the welding torch 4 comes to the most front side within the movable range. In addition, the prescribed position may also be specified by a range, for example, it may be determined as being located at a prescribed position when the front end of the welding torch 4 is located on the front side at a certain ratio or more within the range of the X-axis direction in which the front end of the welding torch 4 can move. When it is determined that the front end of the welding torch 4 is located at the prescribed position (yes in S908), the processing of the welding device 100 proceeds to S910. On the other hand, when the front end of the welding torch 4 is not at the prescribed position (no in S908), the processing of the welding device 100 proceeds to S909.

[0120] In S909, welding device 100 waits for a predetermined time. The waiting time here can be determined based on, for example, the oscillation cycle of welding torch 4. Thereafter, the processing of welding device 100 returns to S904 and the processing is repeated.

[0121] In S910, the welding device 100 extracts a region corresponding to the molten slag bath 7 from the captured image. Figure 5C In this embodiment, the image is subjected to Gaussian blur processing, binarization processing based on brightness, and filling processing outside the largest area with high brightness in sequence, thereby extracting the area. These processes are well known, so the detailed description is omitted here. In addition, the coordinates of the area in the image can also be extracted at the same time.

[0122] In S911, the welding device 100 determines the center of gravity position based on the region corresponding to the molten slag bath 7 extracted in S910. Figure 5C The coordinates of the point Cb of the center of gravity of the region as shown. In addition, as described above, the center of gravity position within a predetermined range may be calculated for the entire region corresponding to the molten slag bath 7. In the present embodiment, the center of gravity position is calculated by focusing on the inner half of the entire region corresponding to the molten slag bath 7. It should be noted that the method for calculating the center of gravity position in the region corresponding to the molten slag bath 7 can use a known calculation formula and is not particularly limited.

[0123] In S912, the welding device 100 adjusts the left-right position of the front end of the welding torch 4 based on the Y-axis direction, i.e., the left-right direction offset between the center of gravity of the molten slag bath 7 and the front end of the welding torch 4 determined in S911. Figure 8As described above, adjustment is performed when the left-right deviation between the center of gravity of the molten slag bath 7 determined in S911 and the tip position of the welding torch 4 exceeds a predetermined threshold. At this time, the tip position of the welding torch 4 can be determined based on the captured image, the setting angle, the oscillation period, etc.

[0124] In S913, the welding device 100 determines whether the welding is completed. Whether the welding is completed can be determined based on an instruction from the user, or can be determined based on the welding device 100 moving a predetermined distance in the upward direction. When it is determined that the welding is completed (Yes in S913), this processing flow ends. On the other hand, when it is determined that the welding is not completed (No in S913), the processing of the welding device 100 returns to S904 and the processing is repeated.

[0125] As described above, according to the present embodiment, in electroslag welding, the influence related to the setting accuracy of the device can be suppressed, and the convenience of the user can be improved. In particular, it is possible to realize high-precision vertical welding while automatically correcting the error of track setting with a relatively simple structure. In addition, vertical welding corresponding to various groove shapes can be performed.

[0126] In addition, the influence of flux spreading can be taken into account and the error of automatic track setting can be corrected with good accuracy. In addition, the generation of a bright arc can be detected and the influence caused thereby can be taken into account and the error of automatic track setting can be corrected with good accuracy. In addition, due to the simple structure, it is also possible to prevent the failure of the welding device and suppress the cost.

[0127] <Other embodiments>

[0128] In the above-mentioned embodiment, an example of adjusting the position of the front end of the welding torch 4 in the left-right direction and the position of the welding sliding copper platen is shown. However, it is not limited to this, and a structure in which the front end position of the welding torch 4 in the depth direction, i.e., the X-axis direction, is adjusted may be adopted. With such a structure, for example, the reference position of the oscillating action can be adjusted, and an oscillating action with higher precision can be performed.

[0129] In the above embodiment, an example using one imaging device 18 is shown, but the present invention is not limited thereto. A plurality of imaging devices may be used to reduce blind spots caused by the welding torch 4 and to configure a region capable of detecting the molten slag bath 7 with greater accuracy.

[0130] In addition, in the above-mentioned embodiment, an example is shown in which the upper surface of the molten slag bath 7 is photographed from directly above, but the present invention is not limited thereto. For example, a structure in which the molten slag bath 7 is photographed from the front side where the sliding copper platen 13 for welding is arranged may be used. With such a structure, the height of the upper surface of the molten slag bath relative to the sliding copper platen 13 for welding can be determined. And by using it in determining whether flux spreading is necessary or not, the determination accuracy can be improved.

[0131] In addition, in the above-mentioned example, blur processing, binarization processing, and area detection are shown as examples of image processing, but the present invention is not limited to these. Figure 3A to Figure 3C As shown, when the shape of the groove of the welding object can be determined in advance, the region can be extracted by matching the region in the image with the pattern of the groove shape. Alternatively, a learned model generated by a well-known machine learning method can be used to perform region detection.

[0132] It should be noted that in this specification, the terms "first" and "second" are used only to distinguish other elements and are not intended to be limited to specific components. Therefore, they may be appropriately renamed according to the structure to which the present invention is applied.

[0133] The present invention can also be implemented by providing a program or application for implementing the functions of one or more of the above-mentioned embodiments to a system or device using a network or storage medium, and one or more processors in a computer of the system or device read out and execute the program.

[0134] Alternatively, the circuit may be implemented by a circuit that implements one or more functions. Examples of the circuit that implements one or more functions include ASIC (Application Specific Integrated Circuit) and FPGA (Field Programmable Gate Array).

[0135] As described above, the following matters are disclosed in this specification.

[0136] (1) An electroslag welding device (e.g., 100), wherein:

[0137] The electroslag welding device (e.g., 100) has:

[0138] A welding torch (e.g., 4) for performing electroslag welding;

[0139] a photographing device (e.g., 18) configured to be able to photograph a molten slag bath (e.g., 7) within a groove (e.g., G) formed by a base material (e.g., 3);

[0140] a determining mechanism (e.g., 15, 202, 203) that determines the area of ​​the molten slag bath from the image captured by the capturing device; and

[0141] An adjustment mechanism (e.g., 15, 204) adjusts the front end position of the welding torch in a first direction (e.g., Y-axis direction) based on a difference between a position of the area determined by the determination mechanism (e.g., Cb) and the front end position of the welding torch in the groove (e.g., Ct).

[0142] According to this structure, in electroslag welding, the influence related to the setting accuracy of the device can be suppressed, and the convenience of the user can be improved. In particular, it is possible to realize high-precision vertical welding while automatically correcting the error of track setting with a relatively simple structure. In addition, it is possible to make vertical welding for various groove shapes possible.

[0143] (2) The electroslag welding device according to (1), wherein:

[0144] The electroslag welding device includes a sliding plate (for example, 13) that is slidable relative to the base material.

[0145] The adjustment mechanism further adjusts the position of the slide plate in the first direction based on the position of the area determined by the determination mechanism.

[0146] According to this structure, the influence related to the installation accuracy of the device can be suppressed, and the convenience of the user can be improved. In particular, the position of the slide plate can be adjusted according to the position of the groove.

[0147] (3) The electroslag welding device according to (1) or (2), wherein:

[0148] The welding torch oscillates along a second direction (e.g., an X-axis direction) that is orthogonal to the first direction.

[0149] The identifying means identifies the region of the molten slag bath using an image when the tip of the welding torch is located at a predetermined position (front side in the X-axis direction) during the oscillating operation.

[0150] According to this configuration, the region of the slag bath can be detected with high accuracy, and the accuracy of position correction can be improved.

[0151] (4) The electroslag welding device according to (3), wherein:

[0152] The adjustment mechanism adjusts the front end position of the welding torch in the first direction based on the difference between the center of gravity position (e.g., Cb) of the determined area of ​​the molten slag bath within a specified range away from the welding torch side in the second direction and the front end position (e.g., Ct) of the welding torch in the first direction.

[0153] According to this configuration, even when a positional deviation in the left-right direction occurs when the rail is installed, for example, the positional adjustment in the left-right direction can be performed with high accuracy.

[0154] (5) The electroslag welding device according to (3) or (4), wherein:

[0155] The adjustment mechanism further adjusts the position of the tip of the welding torch in the second direction based on the position of the area determined by the determination mechanism and the position of the tip of the welding torch in the groove.

[0156] According to this structure, for example, the position adjustment can be performed also in the direction of the oscillating motion. In addition, the user's workload related to the oscillating motion can be reduced, and the user's skill dependence can be reduced.

[0157] (6) The electroslag welding device according to any one of (1) to (6), wherein:

[0158] The electroslag welding device includes a flux spreading control mechanism (e.g., 14) for controlling the spreading of the flux (e.g., 12) to the groove.

[0159] The identifying means identifies the region of the molten slag bath using an image obtained after a predetermined time has passed since flux was sprayed on the groove.

[0160] According to this configuration, the influence of the spreading of the flux can be suppressed and the position adjustment can be performed with high accuracy.

[0161] (7) The electroslag welding device according to (6), wherein:

[0162] The determination means determines that the molten slag bath is insufficient (for example, an open arc) when there is a region consisting of pixels whose blue components and green components have values ​​greater than a predetermined threshold value in the image acquired by the imaging device,

[0163] The flux spreading control mechanism spreads the flux in accordance with the shortage of the molten slag bath.

[0164] According to this configuration, it is possible to detect an open arc and spread flux corresponding to the open arc.

[0165] (8) The electroslag welding device according to (7), wherein:

[0166] The electroslag welding device includes an output mechanism (for example, 19) for notifying the deficiency when it is determined that the molten slag bath is insufficient.

[0167] According to this configuration, it is possible to detect a bright arc and notify it.

[0168] (9) A control method for an electroslag welding device (e.g., 100), wherein:

[0169] The control method of the electroslag welding device (e.g., 100) includes:

[0170] an acquisition step (e.g., S902) of acquiring an image captured by an imaging device (e.g., 18) configured to capture a molten slag bath (e.g., 7) within a groove (e.g., G) formed by a base material (e.g., 3);

[0171] a determining step (e.g., S910, S911), determining the area of ​​the molten slag bath from the image; and

[0172] An adjustment process (e.g., S912) adjusts the front end position of the welding torch (e.g., 4) in the first direction (e.g., Y-axis direction) based on the difference between the position of the area determined by the determination process (e.g., Cb) and the front end position (e.g., Ct) of the welding torch (e.g., 4) in the groove.

[0173] According to this structure, in electroslag welding, the influence related to the installation accuracy of the device can be suppressed, and the convenience of the user can be improved. In particular, it is possible to realize high-precision vertical welding while automatically correcting the error of the track installation with a relatively simple structure.

[0174] Furthermore, vertical welding of various groove shapes can be performed.

[0175] (10) A program, wherein:

[0176] The program is used to make a computer (for example, 15) execute the following steps:

[0177] an acquisition step (e.g., S920) of acquiring an image captured by a camera (e.g., 18) configured to capture a molten slag bath (e.g., 7) in a groove (e.g., G) formed by a base material (e.g., 3);

[0178] a determining step (eg, S910, S911) of determining the region of the molten slag bath from the image; and

[0179] An adjustment process (e.g., S912) adjusts the front end position of the welding torch (e.g., 4) in the first direction (e.g., Y-axis direction) based on the difference between the position of the area determined by the determination process (e.g., Cb) and the front end position (e.g., Ct) of the welding torch (e.g., 4) in the groove.

[0180] According to this structure, in electroslag welding, the influence related to the setting accuracy of the device can be suppressed, and the convenience of the user can be improved. In particular, it is possible to realize high-precision vertical welding while automatically correcting the error of track setting with a relatively simple structure. In addition, it is possible to make vertical welding for various groove shapes possible.

Claims

1. An electroslag welding device, wherein: The electroslag welding device comprises: A welding torch for performing electroslag welding; a photographing device configured to photograph a molten slag bath within a groove formed by a base material; a determining mechanism for determining the area of ​​the molten slag bath from the image captured by the capturing device; as well as An adjustment mechanism adjusts the position of the tip of the welding torch in the first direction based on a difference in the first direction between the position of the area determined by the determination mechanism and the position of the tip of the welding torch in the groove.

2. The electroslag welding device according to claim 1, wherein: The electroslag welding device includes a sliding plate that is slidable relative to the base material. The adjustment mechanism further adjusts the position of the slide plate in the first direction based on the position of the area determined by the determination mechanism.

3. The electroslag welding device according to claim 1, wherein: The welding torch oscillates along a second direction orthogonal to the first direction. The specifying means specifies the region of the molten slag bath using an image when the tip of the welding torch is located at a predetermined position during the oscillating motion.

4. The electroslag welding device according to claim 3, wherein: The adjustment mechanism adjusts the tip position of the welding torch in the first direction based on the difference between the center of gravity position of a specified range of the determined molten slag bath area away from the welding torch in the second direction and the tip position of the welding torch in the first direction.

5. The electroslag welding device according to claim 3, wherein: The adjustment mechanism further adjusts the position of the tip of the welding torch in the second direction based on the position of the area determined by the determination mechanism and the position of the tip of the welding torch in the groove.

6. The electroslag welding device according to claim 1, wherein: The electroslag welding device has a flux spreading control mechanism for controlling the spreading of flux to the groove. The identifying means identifies the region of the molten slag bath using an image obtained after a predetermined time has passed since flux was sprayed on the groove.

7. The electroslag welding device according to claim 6, wherein: The determination means determines that the molten slag bath is insufficient when there is a region consisting of pixels having blue components and green components having values ​​greater than a predetermined threshold value in the image acquired by the imaging device. The flux spreading control mechanism spreads the flux in accordance with the shortage of the molten slag bath.

8. The electroslag welding device according to claim 7, wherein: The electroslag welding device includes an output mechanism for providing a notification regarding the insufficiency when it is determined that the molten slag bath is insufficient.

9. A control method for an electroslag welding device, wherein: The control method of the electroslag welding device comprises: an acquisition step of acquiring an image captured by an imaging device configured to capture a molten slag bath in a groove formed by a base material; a determining step of determining a region of the molten slag bath from the image; and The adjusting step adjusts the position of the tip of the welding torch in the first direction based on the difference in the first direction between the position of the area determined in the determining step and the position of the tip of the welding torch in the groove.

10. A recording medium storing a program, wherein: The program is used to make the computer execute the following steps: an acquisition step of acquiring an image captured by an imaging device configured to capture a molten slag bath in a groove formed by a base material; a determining step of determining a region of the molten slag bath from the image; as well as The adjusting step adjusts the position of the tip of the welding torch in the first direction based on the difference in the first direction between the position of the area determined in the determining step and the position of the tip of the welding torch in the groove.

Images