CN111805062A - Welding observation device and welding system - Google Patents
Welding observation device and welding system Download PDFInfo
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- CN111805062A CN111805062A CN202010268278.2A CN202010268278A CN111805062A CN 111805062 A CN111805062 A CN 111805062A CN 202010268278 A CN202010268278 A CN 202010268278A CN 111805062 A CN111805062 A CN 111805062A
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- 238000003466 welding Methods 0.000 title claims abstract description 182
- 238000003384 imaging method Methods 0.000 claims abstract description 105
- 230000004927 fusion Effects 0.000 claims abstract description 14
- 230000003287 optical effect Effects 0.000 claims description 52
- 230000005540 biological transmission Effects 0.000 claims description 36
- 239000000463 material Substances 0.000 claims description 27
- 238000005516 engineering process Methods 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 19
- 238000010586 diagram Methods 0.000 description 13
- 238000012545 processing Methods 0.000 description 12
- 238000002844 melting Methods 0.000 description 11
- 230000008018 melting Effects 0.000 description 11
- 238000000034 method Methods 0.000 description 7
- 238000000295 emission spectrum Methods 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 238000012795 verification Methods 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 101100165186 Caenorhabditis elegans bath-34 gene Proteins 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 238000004891 communication Methods 0.000 description 4
- 230000001678 irradiating effect Effects 0.000 description 4
- 239000011324 bead Substances 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 2
- 239000010953 base metal Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 241001272720 Medialuna californiensis Species 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 210000001503 joint Anatomy 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 230000005499 meniscus Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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- 239000002893 slag Substances 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/16—Arc welding or cutting making use of shielding gas
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/24—Features related to electrodes
- B23K9/26—Accessories for electrodes, e.g. ignition tips
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/32—Accessories
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Mechanical Engineering (AREA)
- Laser Beam Processing (AREA)
- Arc Welding In General (AREA)
Abstract
The invention provides a technology for judging a molten state just below a welding wire in a molten part according to an image of the molten part only by shooting the image. The welding observation device is a welding observation device for observing a fusion site during arc welding. The welding observation apparatus includes an imaging unit that receives light in a specific wavelength range corresponding to an image capable of identifying a molten state directly below a welding wire and images an image capable of identifying a molten state directly below the welding wire.
Description
The present application claims priority based on japanese patent application No. 2019-076654, applied on 12/4/2019. The entire contents of this Japanese application are incorporated by reference into this specification.
Technical Field
The invention relates to a welding observation device and a welding system.
Background
Conventionally, arc welding has been widely used as a welding method. In such arc welding, if a welding failure (for example, fusion failure due to non-melting of the base material, blowholes due to entrainment of air or gas, or the like) occurs, the welding portion is broken or the strength is reduced, and therefore, it is desirable to observe the molten state of the welding portion to suppress the occurrence of such a welding failure.
Therefore, conventionally, a technique capable of observing a welding portion during arc welding has been proposed. For example, patent document 1 below discloses a welding imaging device in which an optical filter that transmits light of a desired wavelength range and a desired light amount is provided to clearly observe the state of a welded portion, and the light transmitted through the optical filter is received by a CMOS imaging element.
Patent document 1: japanese patent laid-open publication No. 2013-207439
However, in the technique disclosed in patent document 1, since the observation target is a wide range of arc light, a weld pool, and a weld bead, and the wavelength region of light transmitted through the optical filter is a relatively wide region of 410nm to 670nm, only an image in which only arc light with the highest brightness is conspicuous can be captured in the molten portion. Therefore, in the technique disclosed in patent document 1, the molten state just below the wire in the molten portion cannot be determined from the image captured by the welding camera.
In addition, in general, in the conventional techniques, in order to determine the molten state of the molten portion, it is necessary to irradiate the molten portion with a strong laser beam, provide a plurality of imaging devices, or perform special image processing. That is, in the conventional technology, the molten state of the molten portion cannot be discriminated from the image only by capturing the image of the molten portion.
Disclosure of Invention
Therefore, it is expected that the molten state just below the wire in the molten portion can be discriminated from the image by merely photographing the image of the molten portion.
A welding observation device of one embodiment observes a fusion site during arc welding, and includes an imaging unit that receives light in a specific wavelength region corresponding to an image that enables discrimination of a fusion state directly below a welding wire, and captures an image that enables discrimination of a fusion state directly below the welding wire.
According to one embodiment, the molten state just below the wire in the molten portion can be determined from the image by simply capturing the image of the molten portion.
Drawings
Fig. 1 is a diagram showing a configuration of a welding system according to embodiment 1 of the present invention.
Fig. 2 is a schematic configuration diagram of a nozzle provided in a welding torch according to embodiment 1 of the present invention.
Fig. 3 is a diagram showing an example of an image captured by the imaging device according to embodiment 1 of the present invention.
Fig. 4 is a diagram schematically showing a state of a molten portion in the welding apparatus according to embodiment 1 of the present invention.
Fig. 5 is a graph showing an emission spectrum of an arc measured by the inventors in arc welding.
Fig. 6 is a graph showing the result of the inventors deriving the luminous intensity of the molten pool from the formula of planck's radiation law.
Fig. 7 is a diagram showing an example of an image captured by the imaging device according to embodiment 2 of the present invention.
Fig. 8 is an enlarged view of a portion of the image shown in fig. 7.
Fig. 9 is a view schematically showing the state of the fusion site reflected in the image (h) shown in fig. 7 and 8.
In the figure: 1. 2-welding system, 10-welding device, 11-welding torch, 11A-nozzle, 11B-contact tip, 11C-gas supply line, 12-welding wire, 13-power supply device, 14-shielding gas supply device, 15-wire feeder, 20-welding observation device, 21-camera, 21A-optical filter, 21B-camera, 30A-base metal, 30B-base metal, 30C-joint, 32-arc, 34-weld pool, 36-weld bead.
Detailed Description
Hereinafter, embodiments will be described with reference to the drawings.
[ Structure of welding System 1]
Fig. 1 is a diagram showing a configuration of a welding system 1 according to embodiment 1 of the present invention. As shown in fig. 1, the welding system 1 includes a welding apparatus 10 and a welding observation apparatus 20.
(construction of the welding apparatus 10)
The welding apparatus 10 is an apparatus for joining two base materials 30A and 30B by gas metal arc welding. The welding apparatus 10 includes a welding torch 11, a welding wire 12, a power supply device 13, a shielding gas supply device 14, and a wire feeder 15.
The shielding gas supply device 14 is a device for supplying shielding gas to the welding torch 11. The shielding gas is injected from the tip of a nozzle 11A provided in the welding torch 11 to the melting portion, thereby covering the melting portion and preventing the intrusion of the atmosphere into the melting portion. The protective gas is argon or CO2Gas, or argon and CO2A mixture of gases.
The wire feeder 15 is a device that automatically feeds the welding wire 12 to the welding torch 11. As the welding wire 12, a solid wire, a flux-cored wire, or the like can be used.
The power supply device 13 is a device that supplies welding current for generating an arc between the welding wire 12 and the base materials 30A and 30B to the welding wire 12. One electrode of the power supply device 13 is connected to one or both of the two base members 30A and 30B, and the other electrode is connected to a contact tip 11B (see fig. 2) provided in the welding torch 11.
The welding torch 11 has a nozzle 11A, and feeds the welding wire 12 supplied from the wire feeder 15 from the tip of the nozzle 11A to the melting point. The welding torch 11 injects the shielding gas supplied from the shielding gas supply device 14 from the tip of the nozzle 11A toward the melting point. Then, the welding torch 11 supplies the welding current supplied from the power supply device 13 to the welding wire 12 fed from the tip of the nozzle 11A toward the melting point, thereby generating an arc 32 (see fig. 2) between the welding wire 12 and the base materials 30A and 30B. The welding torch 11 is moved by a moving mechanism (not shown) such as a robot arm over the joint portion 30C of the two base materials 30A and 30B, and the joint portion 30C can be welded linearly. The joint portion 30C is a portion where the end surface of the base material 30A and the end surface of the base material 30B abut against each other. The specific structure of the nozzle 11A will be described later with reference to fig. 2.
(construction of nozzle 11A)
Fig. 2 is a schematic configuration diagram of a nozzle 11A provided in a welding torch 11 according to embodiment 1 of the present invention. As shown in fig. 2, a contact tip 11B and a gas supply passage 11C are provided in the cylinder of the nozzle 11A.
The contact tip 11B is a cylindrical member made of metal. The contact tip 11B is made of, for example, a copper material. The welding wire 12 fed from the wire feeder 15 passes through the inside of the tube of the contact tip 11B, and is fed from the tip of the contact tip 11B to the melting point. The contact tip 11B is connected to the other electrode of the power supply device 13, and thereby can supply the welding current supplied from the power supply device 13 to the welding wire 12.
The gas supply passage 11C is provided around the contact tip 11B. The shielding gas supplied from the shielding gas supply device 14 passes through the gas supply passage 11C and is ejected from the tip of the nozzle 11A to the melting point.
In the welding apparatus 10 configured as described above, the welding torch 11 moves on the joint portion 30C of the two base materials 30A and 30B along the joint portion 30C in the extending direction of the joint portion 30C (the direction of arrow a, the positive direction of the X axis in fig. 2). At this time, since the welding current is supplied from the power supply device 13 to the welding wire 12 via the contact tip 11B, the arc 32 is generated between the welding wire 12 and the base materials 30A and 30B. Then, the welding wire 12 and the base materials 30A and 30B are melted by the high heat generated by the arc 32, and the molten metal composed of the molten welding wire 12 and the base materials 30A and 30B forms a molten pool 34 centered directly below the welding wire 12. Then, the molten metal is cooled and solidified, thereby forming a weld bead 36 along the joint portion 30C. Thereby, the two base materials 30A, 30B are welded together.
(Structure of welding observation device 20)
As shown in fig. 1, welding observation apparatus 20 includes an imaging device 21, a communication cable 23, and a processing device 24.
The imaging device 21 is an example of an "imaging means" and captures an image that enables discrimination of a molten state directly below the wire 12 in a molten portion (hereinafter, referred to as a "molten state distinguishable image"). As shown in fig. 1, the imaging device 21 includes an optical filter 21A and an imaging unit 21B.
The optical filter 21A is provided so as to cover the lens surface of the imaging unit 21B. The optical filter 21A transmits light in a specific wavelength range. Light of a specific wavelength region means: light in a wavelength region corresponding to the image distinguishable from the molten state.
The imaging unit 21B receives light of a specific wavelength region transmitted through the optical filter 21A, and captures an image in which the molten state directly below the welding wire 12 can be determined. For example, the imaging unit 21B is configured to include a lens, a sensor (e.g., a CCD sensor, a CMOS sensor, etc.), an image processor, and the like.
In the present embodiment, as the optical filter 21A, a filter having a Full Width at Half Maximum (FWHM) including a center transmission wavelength of 10nm or less is used. In particular, in the present embodiment, as the optical filter 21A, a filter having a center transmission wavelength of any one of 680nm, 720nm, 750nm, 830nm, 840nm, 850nm, 960nm, and 970nm is used. These center transmission wavelengths are preferable wavelengths found by the inventors of the present invention.
Thus, the imaging device 21 can capture a molten state distinguishable image capable of distinguishing the molten state directly below the welding wire 12 in the molten portion by capturing an image of the molten portion (i.e., without irradiating external light, providing a plurality of imaging devices, or performing special image processing).
In the present embodiment, the imaging device 21 is disposed at a preferable position of the imaging device 21, i.e., at a position forward (positive X-axis direction in the drawing) or rearward (negative X-axis direction in the drawing) in the moving direction of the welding torch 11. Fig. 1 shows an example in which the imaging device 21 is disposed forward (in the positive X-axis direction in the drawing) in the movement direction of the welding torch 11. In the present embodiment, the imaging angle θ is preferably set in the range of 40 ° to 50 ° as the imaging device 21 for imaging the melting portion from above. The shooting angle θ is: the angle of depression of the welding torch 11 from above with respect to a plane is assumed while moving on the plane. This imaging angle θ is also a preferable angle found by the inventors of the present invention. For example, if the imaging angle θ exceeds 50 °, a portion immediately below the welding wire 12 may be blocked by the welding torch 11. Further, for example, if the imaging angle θ is smaller than 40 °, the portion directly below the wire 12 may be blocked by the base materials 30A and 30B, and the portion directly below the wire 12 may not be observed.
The imaging device 21 may be configured to move together with the welding torch 11. At this time, even when the welding torch 11 is moved, the imaging direction of the imaging device 21 is not changed, and the imaging angle θ with respect to the molten portion can be maintained within the range of 40 ° to 50 °.
Alternatively, the imaging device 21 may be configured not to move together with the welding torch 11. At this time, when the welding torch 11 is moved, the imaging direction of the imaging device 21 can be kept fixed as long as the imaging angle θ with respect to the molten portion can be maintained within the range of 40 ° to 50 °.
On the other hand, when the welding torch 11 is moved, if the imaging angle θ of the imaging device 21 with respect to the molten portion cannot be maintained within the range of 40 ° to 50 °, the imaging direction can be automatically changed by an arbitrary imaging direction changing mechanism, and thereby the imaging angle θ of the imaging device 21 with respect to the molten portion can be maintained within the range of 40 ° to 50 °. In this case, the imaging direction changing means may calculate the imaging angle θ using a predetermined calculation formula, a predetermined conversion table, or the like, based on the position of the imaging device 21 and the position of the welding torch 11, for example.
The communication cable 23 connects the imaging unit 21B and the processing device 24. The image data of the image captured by the imaging unit 21B is transmitted to the processing device 24 via the communication cable 23. The imaging unit 21B may transmit the image data to the processing device 24 by wireless communication.
The processing device 24 performs various processes on the image data acquired from the imaging unit 21B. For example, the processing device 24 may store the image data acquired from the imaging unit 21B, or may display a fusion state distinguishable image based on the image data acquired from the imaging unit 21B. The imaging unit 21B may capture either a moving image or a still image as a molten state distinguishable image. As the processing device 24, for example, a PC (Personal Computer) or the like is used.
[ 1 st embodiment ]
Hereinafter, embodiment 1 of the welding system 1 according to embodiment 1 will be described. In this embodiment 1, the welding device 10 of the welding system 1 described in embodiment 1 is used to weld two base materials 30A and 30B, and at this time, the image (moving image) of the welded portion is captured by the imaging device 21 and the welded portion is observed. The inventors used LCTF (Liquid Crystal Tunable Filter) as the optical Filter 21A, and examined what image was captured at each center transmission wavelength by sequentially changing the center transmission wavelength of the optical Filter 21A at intervals of 10nm in a range of 650nm to 1100 nm. In addition, the full width at half maximum of the LCTF used in the verification is 10nm or less at any wavelength.
(welding conditions)
The welding conditions used in embodiment 1 are as follows.
The material is as follows: SM490A
Shape of the seam: butt joint
Power mode: DC pulse-free mode
Welding wires: YM-28S (phi 1.2mm)
Projection length: 20mm
Protective gas: ar + 20% CO2(20L/min)
Current: 300A
Voltage: 30V
Welding speed: 30 cm/min
(conditions for shooting)
The shooting conditions used in embodiment 1 are as follows.
A camera: acA2040-90umNIR (manufactured by Basler corporation)
Frame rate: 100Hz
Aperture: f16
External light source: is free of
An optical filter: LCTF (650 to 1100nm)
Exposure time: 3000 mus
The observation direction is as follows: front side
Shooting angle θ: 45 degree
(results of verification)
Fig. 3 is a diagram showing an example of an image captured by the imaging device 21 according to embodiment 1 of the present invention. Fig. 3 (b) is a diagram showing a representative example of an image captured by the imaging device 21 when the central transmission wavelength of the optical filter 21A is 680nm, 720nm, 750nm, 830nm, 840nm, 850nm, 960nm, or 970 nm. Fig. 3 (a) and (c) are views showing a typical example of an image captured by the imaging device 21 when the center transmission wavelength of the optical filter 21A is a value other than the above values.
As shown in fig. 3 (b), when the center transmission wavelength of the optical filter 21A is 680nm, 720nm, 750nm, 830nm, 840nm, 850nm, 960nm, or 970nm, the amount of light of the arc 32 is appropriate in the image captured by the imaging device 21. Therefore, the inventors can determine the molten state just below the wire 12 in the molten portion from the image.
On the other hand, when the center transmission wavelength of the optical filter 21A is a value other than the above value, as shown in fig. 3 (a), the amount of light of the arc 32 becomes excessive in the image captured by the imaging device 21, and the entire melted portion becomes white. Therefore, the inventors cannot determine the molten state directly below the wire 12 in the molten portion from the image. Alternatively, as shown in fig. 3 (c), in the image captured by the imaging device 21, the amount of light of the arc 32 becomes too small, and the entire melted portion becomes dark. Therefore, the inventors cannot determine the molten state directly below the wire 12 in the molten portion from the image.
From the above-described verification results, it was confirmed that a molten state distinguishable image capable of discriminating the molten state directly below the welding wire 12 in the molten portion was able to be captured by setting the full width at half maximum of the optical filter 21A to 10nm and setting the center transmission wavelength of the optical filter 21A to any one of 680nm, 720nm, 750nm, 830nm, 840nm, 850nm, 960nm, and 970 nm.
(State of molten portion)
Fig. 4 is a diagram schematically showing a state of a molten portion in welding apparatus 10 according to embodiment 1 of the present invention. Fig. 4 (a) is a diagram schematically showing the state of the molten portion when viewed from the left side (negative direction of Y axis in the figure). Fig. 4 (b) is a schematic view showing the state of the molten portion when viewed from the front (positive X-axis direction in the figure) and from above (positive Z-axis direction in the figure). That is, fig. 4 (b) is a diagram schematically showing the state of the fusion site when viewed from the same direction as the imaging device 21.
In fig. 4 (a) and (b), a region 32A surrounded by a broken line indicates a region of the arc 32. In fig. 4 (a) and B), a hatched region 38 is a portion immediately below the welding wire 12 in the molten portion, and is a region where the welding wire 12 and the base materials 30A and 30B are directly melted by the arc 32. That is, the region 38 is a region where it is desired to be able to discriminate the molten state. The welding apparatus 10 of the present embodiment captures a molten state distinguishable image so that the molten state of the region 38 can be discriminated.
As shown in fig. 4 (a) and (b), the region 38 is a region included in the range of the arc 32, and is a region in the central portion of the region 32A of the arc 32. Therefore, as illustrated in fig. 3 (a), if the light amount of the arc 32 becomes excessive in the image captured by the imaging device 21, the entire area 32A of the arc 32 becomes white. Therefore, the inventors cannot determine the molten state of the region 38 from the image.
Therefore, in welding device 10 of the present embodiment, the molten state of image area 38 captured by imaging device 21 can be determined by determining the transmission characteristics of optical filter 21A so that the amount of light incident on arc 32 of imaging device 21 is appropriate, as illustrated in fig. 3 (b).
As described above, the welding observation apparatus 20 according to embodiment 1 of the present invention is a welding observation apparatus 20 that observes a molten portion during arc welding, and includes the imaging device 21, and the imaging device 21 receives light in a specific wavelength region corresponding to an image that enables discrimination of a molten state directly below the welding wire 12 and captures an image that enables discrimination of a molten state directly below the welding wire 12.
Accordingly, welding observation apparatus 20 according to embodiment 1 of the present invention can determine the molten state directly below welding wire 12 from the image captured by imaging apparatus 21 without irradiating a molten portion with a strong laser beam, without providing a plurality of imaging apparatuses, or without performing special image processing. Therefore, according to welding observation apparatus 20 according to embodiment 1 of the present invention, the molten state directly below welding wire 12 in the molten portion can be determined from the image of the molten portion by simply capturing the image.
Further, in welding observation apparatus 20 according to embodiment 1 of the present invention, imaging apparatus 21 includes: an optical filter 21A that transmits light in a specific wavelength region; and an imaging unit 21B that receives light of a specific wavelength region transmitted through the optical filter 21A to capture an image that enables determination of the molten state directly below the wire 12.
Accordingly, welding observation apparatus 20 according to embodiment 1 of the present invention can capture an image in which the molten state directly below welding wire 12 can be discriminated by a relatively simple configuration in which only optical filter 21A is provided for imaging unit 21B.
In welding observation apparatus 20 according to embodiment 1 of the present invention, optical filter 21A has a characteristic of transmitting light in a specific wavelength region having a full width at half maximum of 10nm or less.
As a result, welding observation apparatus 20 according to embodiment 1 of the present invention can capture an image in which the molten state directly below welding wire 12 can be favorably determined.
In welding observation apparatus 20 according to embodiment 1 of the present invention, the center transmission wavelength of optical filter 21A is any one of 680nm, 720nm, 750nm, 830nm, 840nm, 850nm, 960nm, and 970 nm.
As a result, welding observation apparatus 20 according to embodiment 1 of the present invention can capture an image in which the molten state directly below welding wire 12 can be favorably determined.
In welding observation apparatus 20 according to embodiment 1 of the present invention, imaging device 21 is disposed in front of or behind welding apparatus 10 in the moving direction, and has an imaging angle θ from above with respect to the molten portion.
As a result, welding observation apparatus 20 according to embodiment 1 of the present invention can capture an image from an imaging direction in which a molten state directly below welding wire 12 can be favorably determined.
In welding observation apparatus 20 according to embodiment 1 of the present invention, imaging angle θ of imaging device 21 is in the range of 40 ° to 50 °.
As a result, welding observation apparatus 20 according to embodiment 1 of the present invention can capture an image from an imaging direction in which a molten state directly below welding wire 12 can be favorably determined.
Further, a welding system 1 according to embodiment 1 of the present invention includes: a welding device 10 for welding arc welding bases 30A and 30B; and a welding observation device 20 for observing a fusion site during arc welding.
Thus, welding system 1 according to embodiment 1 of the present invention can determine the molten state directly below welding wire 12 from the image captured by imaging device 21 provided in welding observation device 20 without irradiating a strong laser beam to the molten portion, providing a plurality of imaging devices, or performing special image processing. Therefore, according to the welding system 1 of embodiment 1 of the present invention, the molten state of the molten portion can be determined from the image by simply capturing the image of the molten portion.
[ 2 nd embodiment ]
Next, embodiment 2 will be described with reference to the drawings. Hereinafter, the welding system 2 according to embodiment 2 will be mainly described about differences from the welding system 1.
The configuration of the welding system 2 according to embodiment 2 is substantially the same as the configuration of the welding system 1 shown in fig. 1. However, the imaging unit 21B and the optical filter 21A in the welding system 2 according to embodiment 2 are different from the welding system 1 according to embodiment 1. As a result, the welding system 2 according to embodiment 2 can capture an image in which the molten state distinguishable image can be easily distinguished from the state of a wider area of the molten pool 34.
In welding system 2 according to embodiment 2, a near-infrared camera capable of capturing a near-infrared image is used as imaging unit 21B. Specifically, in welding system 2 according to embodiment 2, a near-infrared camera capable of capturing an image of light in a near-infrared wavelength region (i.e., a wavelength region of 980 to 1650nm) is used as imaging unit 21B.
In welding system 2 according to embodiment 2, an optical filter 21A including a filter having a full width at half maximum (FWHM) of a center transmission wavelength of 10nm or less and a center transmission wavelength of 1300nm, 1310nm, or 1320nm is used. These center transmission wavelengths are more preferable wavelengths found by the inventors of the present invention.
Thus, the imaging device 21 according to embodiment 2 can capture a molten state distinguishable image in which the state of the portion directly below the wire 12 in the molten pool 34 and the surrounding portion thereof can be easily discriminated by capturing an image of the molten portion (that is, without irradiating external light, providing a plurality of imaging devices, or performing special image processing). That is, the imaging device 21 according to embodiment 2 can capture a molten state distinguishable image in which the state of a wider area of the molten pool 34 can be easily discriminated.
(preferred method of deriving center transmission wavelength)
Hereinafter, a method of deriving a preferred center transmission wavelength by the inventors of the present invention will be described with reference to fig. 5 and 6.
Fig. 5 is a graph showing an emission spectrum of an arc measured by the inventors in arc welding. As shown in fig. 5, the emission intensity of the arc during arc welding is extremely low in the wavelength region of near-infrared light (850nm — 850 nm) compared with the wavelength regions of ultraviolet light and visible light. Based on this fact, the inventors of the present invention have found that the brightness of the arc can be reduced in the molten state distinguishable image by combining the image pickup device 21 with a band pass filter which transmits only light in the near infrared region and then capturing the molten state distinguishable image.
Fig. 6 is a graph showing the result of deriving the luminous intensity of the molten pool from the formula of planck's law of radiation by the inventors. In the graph shown in fig. 6, the luminous intensity of the molten pool is shown in terms of the surface temperature. As shown in fig. 6, when the surface temperature of the molten pool during arc welding is 1950 ℃ which is normal, the light emission intensity of the molten pool becomes the strongest in the wavelength region around 1310 nm. From this fact, the inventors of the present invention have found that the molten state distinguishable image can be obtained by capturing an image based on the molten state of light having a wavelength near 1310nm (any one of 1300nm, 1310nm, and 1320 nm) by the imaging device 21, and the brightness of the molten pool can be increased in the molten state distinguishable image.
Each emission spectrum shown in fig. 6 is calculated by the inventors of the present invention using planck's law expressed by the following equation (1).
[ mathematical formula 1]
The parameters in the above formula (1) are as follows.
E: radiant energy
L: wavelength of light
C: speed of light (299,792,458)
H: planck constant
K: boltzmann constant
T: temperature of
As described above, the inventors of the present invention have found that by setting the center transmission wavelength of the optical filter 21A to near infrared light (900nm — 900 nm) and either 1300nm, 1310nm, or 1320nm, it is possible to capture an image in which the molten state distinguishable image in a wider range of the molten pool 34 can be easily recognized with the brightness of the arc 32 suppressed and the brightness of the molten pool 34 improved.
In the present embodiment, iron is used as the material of the base materials 30A and 30B, and the center transmission wavelength of the optical filter 21A is derived as described above. Therefore, when a material other than iron (for example, aluminum or the like) is used as the material of the base materials 30A and 30B, the emission spectra of the arc and the molten pool may be different from the graphs shown in fig. 5 and 6. However, in this case, the center transmission wavelength of the optical filter 21A may be derived from the emission spectrum of the arc and the molten pool corresponding to the material.
[ example 2 ]
Hereinafter, example 2 of welding system 2 according to embodiment 2 will be described. In this 2 nd embodiment, when two base materials 30A and 30B are welded by using the welding device 10 of the welding system 2 according to the 2 nd embodiment, an image (moving image) of the welded portion is captured by the imaging device 21 and the welded portion is observed. The inventors used a bandpass filter different from that of example 1 as the optical filter 21A, and examined what image was captured at each center transmission wavelength by sequentially changing the center transmission wavelength of the optical filter 21A in the range of 980nm to 1600 nm. The full width at half maximum of the bandpass filter used in this verification was 10nm or less at any wavelength.
(welding conditions)
The welding conditions used in embodiment 2 are the same as those used in embodiment 1.
(conditions for shooting)
The shooting conditions used in embodiment 2 are as follows.
A camera: near infrared camera (sensor sensitivity: 980 to 1650nm) (manufactured by Xenics Co., Ltd.)
Frame rate: 100Hz
Aperture: f16
External light source: is free of
An optical filter: band-pass filter (980 nm to 1650nm)
The observation direction is as follows: front side
Shooting angle θ: 45 degree
(results of verification)
Fig. 7 is a diagram showing an example of an image captured by the imaging device 21 according to embodiment 2 of the present invention. Fig. 8 is an enlarged view of a portion of the image shown in fig. 7.
The image (a) in fig. 7 is an image captured by the imaging device 21 without the optical filter 21A as a comparative example.
Images (b) to (f) and (j) to (l) in fig. 7 are images captured by the imaging device 21 as comparative examples, with the center transmission wavelengths of the optical filter 21A being 980nm, 1030nm, 1064nm, 1100nm, 1200nm, 1400nm, 1520nm, and 1600 nm.
Images (g), (h), and (i) in fig. 7 and 8 are images captured by the imaging device 21 with the center transmission wavelengths of the optical filter 21A set at 1300nm, 1310nm, and 1320nm, which are preferred embodiments found by the present inventors.
As shown in images (b) to (f) and (j) to (l) in fig. 7 and 8, when the center transmission wavelength of the optical filter 21A is a wavelength other than 1300nm, 1310nm, and 1320nm, the brightness of the molten pool 34 is insufficient over a wide range, and the image is not clear. Therefore, it is difficult to distinguish the state of the molten pool 34 over a wide range of the molten pool 34 from the images (b) to (f) and (j) to (l).
On the other hand, as shown in images (g), (h), and (i) in fig. 7 and 8, when the center transmission wavelength of the optical filter 21A is set to any one of 1300nm, 1310nm, and 1320nm, the brightness of the arc 32 is suppressed in the region 38 directly below the arc 32 in the molten pool 34, and the image becomes clear, whereas the brightness is increased in the other regions in the molten pool 34, and the image becomes clear. Therefore, in the images (g), (h), and (i), the outer peripheral edge portion of the meniscus shape of the continuous melting bath 34 (the boundary between the molten bath 34 and the base materials 30A and 30B) can be recognized, that is, the state of the molten bath 34 (for example, foreign matters such as bubbles and slag; fusion failure, blowholes, and flow of molten metal) over a wide range of the molten bath 34 (but not including a dead space portion formed by the nozzle 11A) can be easily determined.
In the images (g), (h), and (i), the outer peripheral edge of the molten pool 34 has a substantially half-moon shape because a part of the molten pool 34 is covered with the nozzle 11A when viewed from the imaging device 21, and therefore a dead space is generated in the molten pool 34.
In this way, in example 2, it was confirmed that an image in which the state of the molten pool 34 in a wide range can be easily discriminated can be captured by setting the center transmission wavelength of the optical filter 21A to any one of 1300nm, 1310nm, and 1320 nm.
(State of molten portion)
Fig. 9 is a schematic view showing the state of the fusion site shown in the image (h) shown in fig. 7 and 8.
As shown in fig. 9, in the image (h), since the center transmission wavelength of the optical filter 21A is 1310nm, the brightness of the molten pool 34 is improved, and thus the image is clearly reflected over a wide range of the molten pool 34 (but not including a blind spot portion formed by the nozzle 11A), and the molten state can be easily recognized.
Further, as shown in fig. 9, in the image (h), since the center transmission wavelength of the optical filter 21A is set to 1310nm (near infrared light), the brightness of the arc 32 is suppressed, and thus the image is clearly reflected also in the region 38 directly below the arc 32 in the molten pool 34, and the molten state can be easily recognized.
In fig. 9, the region 38 is a region immediately below the welding wire 12 in the molten portion, and is also a region in which the welding wire 12 and the base materials 30A and 30B are directly melted by the arc 32.
As described above, in welding observation apparatus 20 according to embodiment 2 of the present invention, the center transmission wavelength of optical filter 21A is any one of 1300nm, 1310nm, and 1320 nm.
As a result, welding observation apparatus 20 according to embodiment 2 of the present invention can adjust the brightness of region 38 directly below arc 32 in molten pool 34 and the brightness of the other region in molten pool 34 in the image captured by imaging apparatus 21 to an appropriate brightness. Therefore, the welding observation apparatus 20 according to embodiment 2 of the present invention can capture an image in which the molten state over a wide range of the molten pool 34 (however, the molten state does not include the blind spot portion formed by the nozzle 11A) can be favorably discriminated.
In addition, the imaging device 21 (near infrared camera) of embodiment 2 can observe the state of the wide area of the molten pool 34, compared to the imaging device 21 (visible light camera) of embodiment 1, but is expensive. However, the imaging device 21 according to embodiment 1 is sufficient to observe only the state directly below the arc 32. Therefore, for example, in the case of giving priority to cost, the imaging device 21 of embodiment 1 may be adopted, and in the case of giving priority to the observation range of the molten pool 34, the imaging device 21 of embodiment 2 may be adopted.
Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.
For example, the full width at half maximum and the center transmission wavelength of the optical filter 21A are not limited to those exemplified in the embodiments. That is, the full width at half maximum and the center transmission wavelength of the optical filter 21A can be appropriately changed according to various welding conditions and various imaging conditions so that an image that can discriminate the molten state directly below the wire can be captured.
For example, the optical filter 21A may be a filter having a fixed light transmission characteristic or a filter having a variable light transmission characteristic.
For example, in the above embodiment, the imaging unit 21B and the optical filter 21A are provided separately, but the present invention is not limited to this, and the optical filter 21A may be provided integrally with the imaging unit 21B. The imaging unit 21B may have a structure capable of selectively receiving light of a specific wavelength region (for example, an imaging element capable of selectively receiving light of a specific wavelength region) instead of the optical filter 21A.
Claims (8)
1. A welding observation device for observing a fusion site during arc welding,
the welding wire welding device is provided with an imaging mechanism which receives light in a specific wavelength region corresponding to an image capable of distinguishing a molten state right below a welding wire and captures an image capable of distinguishing the molten state right below the welding wire.
2. The welding viewing device of claim 1,
the imaging mechanism includes:
an optical filter which transmits light in the specific wavelength region; and
and an imaging unit that receives the light of the specific wavelength region transmitted through the optical filter and captures an image in which a molten state directly below the wire can be determined.
3. The welding viewing device of claim 2,
the optical filter has a characteristic of transmitting light in the specific wavelength region having a full width at half maximum of 10nm or less.
4. The welding viewing device of claim 3,
the center transmission wavelength of the optical filter is any one of 680nm, 720nm, 750nm, 830nm, 840nm, 850nm, 960nm and 970 nm.
5. The welding viewing device of claim 3,
the center transmission wavelength of the optical filter is 1300nm, 1310nm or 1320 nm.
6. The welding observation apparatus of any one of claims 1 to 5,
the imaging mechanism is disposed in front of or behind the movement direction of the welding torch, and has an imaging angle θ from above with respect to the fusion site.
7. The welding viewing device of claim 6,
the shooting angle theta of the shooting mechanism is within the range of 40-50 degrees.
8. A welding system is characterized by comprising:
a welding device for arc welding a base material; and
the welding observation apparatus according to any one of claims 1 to 7 for observing a fusion site in the arc welding.
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| CN112882435A (en) * | 2020-12-28 | 2021-06-01 | 中国核工业第五建设有限公司 | Data acquisition and image processing control system and method suitable for narrow space |
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