An automated welding system and method for achieving full penetration of fillet welds in thick plates.

Abstract

This invention discloses an automated welding system and method for achieving full penetration of fillet welds in thick plates, belonging to the field of welding technology. It includes at least two linear motion systems and at least two welding devices, with the linear motion systems and welding devices respectively positioned on both sides of the plate to be welded, moving at the same speed along the weld direction on the plate. Each welding device includes an industrial robot mounted on one of the linear motion systems, and a welding torch positioned at the output end of the industrial robot, maintaining a constant distance and angle from the weld. This invention then uses the industrial robot to adjust the position and posture of the welding torch, controlling the welding devices on both sides to simultaneously weld the plate to be welded; this not only eliminates the grinding process, significantly saving costs and reducing material usage, but also allows for simultaneous welding on both sides, greatly saving 66% of labor time.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, and in particular to an automatic welding system and method for achieving full penetration of thick plate fillet welds. Background Technology

[0002] As the primary structural form of long-span bridges, the welding quality of steel structure bridges directly affects the overall construction and engineering quality. Furthermore, the design service life of long-span bridges is often several decades or even centuries, which places stricter requirements on the welding quality of steel structure bridges. In the construction of steel structure bridges, to ensure weld penetration, welding requirements have gradually evolved from single-sided partial penetration welding to double-sided full penetration welding, increasing the weldable depth and thus improving the fatigue strength and service life of the steel structure bridge.

[0003] Thick plate welding using a deep penetration welding machine can achieve full penetration welding, provided that the welding torch maintains a constant distance from the weld and a constant angle (ideally perpendicular to the weld normal). However, thick plate welding is often not a perfectly straight line; the weld seam is curved, arc-shaped, or wavy. Therefore, real-time weld seam tracking is required to guide and adjust the position and orientation of the welding torch to track the weld and maintain a constant angle (ideally perpendicular to the weld normal).

[0004] Currently, all weld seam tracking systems on the market, including those imported from abroad, can only track the spatial position of the weld seam, but cannot automatically adjust the posture of the welding torch. The posture of the robot welding torch needs to be preset manually at a fixed position. This is because it cannot achieve deep penetration automatic welding for thick plates with uncertain bending or corrugated weld seams (and may even cause frequent torch collisions). Summary of the Invention

[0005] To overcome the above-mentioned technical defects, the present invention provides an automatic welding system and method for full penetration of thick plate fillet welds, so as to solve the problems involved in the background art.

[0006] This invention provides an automated welding system and method for achieving full penetration of fillet welds in thick plates, comprising:

[0007] At least two linear motion systems are arranged on both sides of the plate to be welded and move along the weld direction on the plate at the same speed; the plate to be welded includes a first plate placed horizontally, a second plate placed on the first plate at a predetermined angle, and a bevel provided on one side of the second plate.

[0008] At least two welding devices are located on both sides of the plates to be welded; the welding devices include industrial robots respectively mounted on the linear motion system, and welding torches mounted on the output end of the industrial robots, which always maintain a constant distance from the weld and a constant angle with the normal vector of the weld on the second plate.

[0009] Preferably or optionally, the automatic welding system further includes at least two laser tracking devices located on both sides of the plate to be welded;

[0010] The laser tracking device includes a column disposed on one side of the transmission device, a linear motion module mounted on the column and parallel to the transmission surface of the transmission device, and a laser tracking system mounted on the output end of the linear motion module and whose spacing relative to the weld seam is always consistent or within a predetermined range.

[0011] Preferably or optionally, the linear motion system includes: a linear guide rail disposed on one side of the transmission device, and a trolley slidably mounted on the linear guide rail;

[0012] The laser tracking device and welding device are installed on the upper surface of the mobile vehicle.

[0013] Preferably or optionally, the automatic welding system further includes an electrical control cabinet disposed on the upper surface of the mobile trolley, the electrical control cabinet being signal-connected to the laser tracking device, the welding device and the mobile trolley respectively.

[0014] Preferably or optionally, the industrial robot includes at least 6 degrees of freedom.

[0015] Preferably or optionally, the industrial robot includes: a base; a waist rotation mechanism rotatably mounted on the base; a large arm mechanism rotatably mounted on the waist rotation mechanism; a forearm mechanism rotatably mounted at the other end of the large arm mechanism; a wrist mechanism rotatably disposed at the other end of the forearm mechanism; and an end effector rotatably mounted at the other end of the wrist mechanism for mounting a welding torch.

[0016] Preferably or optionally, the welding torches are all deep penetration welding torches.

[0017] Preferably or optionally, the first and second plates are pre-assembled together by manual spot welding.

[0018] Preferably or optionally, a transmission device is provided between the two linear motion systems, which is suitable for conveying the plate to be welded to the processing station.

[0019] The present invention also provides a welding method for an automatic welding system for full penetration of fillet welds in thick plates, comprising:

[0020] Step 1: Place the second plate to be beveled at a predetermined angle at a predetermined position on the first plate and pre-install it to form the plate to be welded;

[0021] Step 2: Transfer the sheet metal to be welded to the processing station of the automatic welding system;

[0022] Step 3: Obtain the weld path of the plate to be welded using a laser tracking device;

[0023] Step 4: Driven by the linear motion system, the welding guns on both sides of the plate to be welded move along the weld seam at a predetermined speed, and the welding points of the welding guns on both sides are always located at the same position on the weld seam path; then the industrial robot adjusts the position of the welding guns so that the welding guns always maintain a constant distance from the weld seam and a constant angle with the normal vector of the weld seam on the second plate, while welding is performed on both sides of the plate to be welded.

[0024] This invention relates to an automated welding system and method for achieving full penetration of fillet welds in thick plates, which has the following advantages compared to existing technologies:

[0025] 1. This invention, through the design of a laser tracking device and an industrial robot, automatically and in real-time adjusts the spatial position (TCP) of the robot welding torch to maintain a constant distance from the weld seam, while simultaneously and in real-time adjusting the welding torch posture to maintain a constant angle (preferably perpendicular to the weld seam). This enables the tracking welding of weld seams of the sheet metal to be welded, including arbitrary bends, arcs, angles, and corrugations, thereby achieving the best welding effect.

[0026] 2. This invention adds a servo motor-driven linear motion module to the laser tracking system, ensuring that the laser tracking system remains within the optimal measurement range of the weld seam. This effectively expands the application scenarios of the laser tracking system and accurately acquires the path of irregularly shaped weld seams. It keeps the laser at its optimal tracking range and, by superimposing the laser's detection data, obtains the true spatial coordinates of the weld seam.

[0027] 3. By mounting the laser tracking device and welding device on a linear motion system, this invention can greatly improve the movement accuracy of the laser tracking device and welding device, and ensure the welding uniformity of the plates to be welded.

[0028] 4. The present invention is equipped with a control device that organically connects the laser tracking device, the welding device, and the moving carriage. The weld path is obtained through the laser tracking device, and the welding parameters are adjusted in a timely manner according to the position of the welding torch relative to the weld path, thereby ensuring the welding quality.

[0029] 5. By employing an industrial robot with at least 6 degrees of freedom, this invention can not only compensate for the spatial position of the welding torch in the weld seam, but also automatically adjust the posture of the welding torch so that the welding torch is always perpendicular to the weld seam path or maintains a constant angle with the weld seam path, thereby achieving a more perfect welding effect.

[0030] 6. This invention reduces the number of welding operations and improves welding quality by simultaneously performing deep welding on both sides of the plates to be welded using a deep penetration welding torch.

[0031] 7. This invention welds two plates together by manual spot welding, without the need for other fixing devices, which facilitates subsequent automated processing.

[0032] 8. By setting up a transmission device, the present invention facilitates the transportation of the plates to be welded and improves the automation level of the entire equipment.

[0033] 9. This invention uses automated equipment to weld both sides of the plates to be welded simultaneously, ensuring the welding quality on both sides. It eliminates the need for beveling, which can significantly save costs, reduce material usage, improve efficiency, and reduce labor.

[0034] 10. This invention uses an industrial robot to adjust the position of the welding torch and control the welding devices on both sides to weld the plates to be welded simultaneously; it not only eliminates the grinding process, greatly saving costs and reducing materials, but also saves 66% of labor time by welding simultaneously on both sides. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the automatic welding system in this invention.

[0036] Figure 2 This is a structural schematic diagram of one side of the automatic welding system in this invention.

[0037] Figure 3 This is a top view of one side of the automatic welding system in this invention.

[0038] Figure 4 This is a side view of one side of the automatic welding system of the present invention.

[0039] Figure 5 This is a schematic diagram of the laser tracking device in this invention.

[0040] Figure 6 This is a schematic diagram of the welding device in this invention.

[0041] The attached figures are labeled as follows: laser tracking device 500, column 510, telescopic module 520, laser tracking system 530, angle adjustment device 540, lifting module 550, mounting base 521, servo motor 522, linear motion module 523, sliding base 524, cable chain 525.

[0042] Welding device 600, industrial robot 610, welding torch 620, base 611, waist rotation mechanism 612, upper arm mechanism 613, forearm mechanism 614, wrist mechanism 615, end effector 616.

[0043] Linear motion system 700, linear guide rail 710, moving trolley 720

[0044] Electrical control cabinet 800

[0045] A. Corrugated plate, B. Top plate, C. Weld path, D. Bevel. Detailed Implementation

[0046] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0047] See appendix Figures 1 to 6 An automated welding system for full penetration of fillet welds in thick plates includes: at least two linear motion systems 700, at least two welding devices 600, and at least two laser tracking devices 500.

[0048] Two linear motion systems 700 are respectively positioned on both sides of the plate to be welded, and move along the weld seam direction on the plate at the same speed. The plate to be welded includes a first plate placed horizontally, a second plate placed on the first plate at a predetermined angle, and a bevel D on one side of the second plate. Two laser tracking devices 500 and a welding device 600 are mounted on the linear motion systems 700, respectively located on both sides of the plate to be welded. The welding device 600 includes an industrial robot 610 mounted on the linear motion systems 700, and a welding torch 620 mounted at the output end of the industrial robot 610, maintaining a constant distance from the weld seam and a constant angle with the normal vector of the weld seam on the second plate. The weld seam path C is obtained by the laser tracking devices 500, and then, based on the position and orientation of the welding torch 620 relative to the weld seam path C, the industrial robot 610 adjusts the orientation of the welding torch 620, controlling the welding devices 600 on both sides to simultaneously weld the plate to be welded. By designing a laser tracking device 500 and an industrial robot 610 in conjunction, the space position (TCP) of the welding torch and the distance between it and the weld seam are automatically and in real time adjusted to maintain a constant distance. At the same time, the posture of the welding torch is also automatically and in real time adjusted to maintain a constant angle with the weld seam (preferably perpendicular to the weld seam). This enables the tracking welding of weld seams of the sheet metal to be welded, which can be arbitrarily curved, arc-shaped, inclined, or corrugated, thereby achieving the best welding effect.

[0049] Since neither the first nor the second plate is a regular shape, please refer to the appendix. Figure 1 Appendix Figure 2 The first plate is the top plate B, which is designed with a certain curvature according to the requirements of the bridge, generally 0 to 10°; the second plate is the corrugated plate A, with a wavy cross-section, and is installed on the top plate B with the same curvature; the traditional laser tracking system 530 has a small measurement range of about 150 mm, which is not large enough for such a large-amplitude curved weld in the field of thick plates.

[0050] See appendix Figure 5 This embodiment proposes an adaptive laser tracker servo guidance system. The laser tracking device 500 includes: a column 510 disposed on one side of the transmission device; a linear motion module 523 mounted on the column 510 and parallel to the transmission surface of the transmission device; and a laser tracking system 530 mounted on the output end of the linear motion module 523 and whose spacing relative to the weld seam remains consistent or within a predetermined range. The laser tracking system 530 maintains an optimal tracking range at all times. Furthermore, laser tracking systems 530 are disposed on both sides of the plate to be welded. By superimposing the detection data from both laser tracking systems 530, the true spatial coordinates of the weld seam are obtained.

[0051] The column 510 is vertically installed on the working plane, and a transmission device is provided on the working plane to transport the plates to be welded, facilitating the transportation of the plates and improving the automation level of the entire equipment. In this embodiment, the column 510 is located on one side of the transmission device, and the laser tracking device 500 is installed on one side of the transmission device.

[0052] The linear motion module 523 includes: a servo motor 522 fixedly mounted on the mounting base 521; a lead screw mounted on the mounting base 521 and driven by the servo motor 522; guide rails disposed on both sides of the lead screw; and a sliding seat 524 slidably mounted on the lead screw and the guide rails. Of course, those skilled in the art will recognize that the linear motion module 523 can also be other types of programmable linear modules, which will not be elaborated upon here.

[0053] In addition, a drag chain 525 is provided on the mounting base 521, which is suitable for accommodating control lines and power supply lines. The control lines and power supply lines are connected to the servo motor 522 and are suitable for controlling the opening and closing and speed of the servo motor 522.

[0054] The laser tracking system 530 is mounted on the output end of the linear motion module 523, forming a predetermined angle with the working plane. The predetermined angle ranges from 15° to 75°, preferably 45°. Furthermore, driven by the linear motion module, the distance between the laser tracking system 530 and the weld seam remains consistent or within a predetermined range, ensuring that the weld seam is always within the optimal measurement range of the laser tracking system 530.

[0055] The laser tracking system 530 is a commercially available product. In this embodiment, the laser tracking system 530 includes: a mounting bracket fixedly installed on the sliding seat 524; a laser generator disposed on the mounting bracket with its emission port always facing the weld; and a laser detector mounted on the mounting bracket and adapted to acquire the laser signal reflected back from the target.

[0056] In a further embodiment, the column 510 is also equipped with a lifting module 550, and a telescopic module 520 is installed on the output end of the lifting module 550. An angle adjustment device 540 is also provided between the sliding seat 524 and the laser tracking system 530. When producing products of different types and specifications, users can adjust the height of the laser tracking system 530 relative to the working plane and the predetermined angle with the working plane through the lifting module 550 and the angle adjustment device 540, optimize relevant detection parameters, and improve the application range of the laser weld seam tracking device.

[0057] In a further embodiment, the welding device 600 includes: an industrial robot 610 disposed on one side of the transmission device, and a welding torch 620 disposed at the output end of the industrial robot 610, maintaining a constant angle with the weld seam. The industrial robot 610 has at least six degrees of freedom. Through the cooperation of the six-axis robot and the welding torch 620, the entire welding device 600 can not only compensate for the spatial position of the weld seam, but also automatically adjust the posture of the welding torch 620, ensuring that the welding torch 620 is always perpendicular to the weld seam path C or maintains a constant angle with the weld seam path C, thereby achieving a more perfect welding effect.

[0058] See appendix Figure 6 This embodiment provides an exemplary structure of a six-axis robot. The industrial robot 610 includes: a base 611; a waist rotation mechanism 612 rotatably mounted on the base 611; a large arm mechanism 613 rotatably mounted on the waist rotation mechanism 612; a forearm mechanism 614 rotatably mounted on the other end of the large arm mechanism 613; a wrist mechanism 615 rotatably disposed on the other end of the forearm mechanism 614; and an end effector 616 rotatably mounted on the other end of the wrist mechanism 615 for mounting a welding torch 620.

[0059] In a further embodiment, since the deep penetration welding torch 220 uses digitally controlled arc curve parameters to further compress the arc, the arc heat is more concentrated and has better penetration ability, thus increasing the welding penetration depth. Therefore, there is no need for reverse root cleaning, and the groove size can be optimized while ensuring the penetration depth. This can reduce the consumption of welding materials, reduce costs, and improve efficiency.

[0060] In a further embodiment, the linear motion system 700 includes: a linear guide rail 710 disposed on one side of the transmission device, and a trolley 720 slidably mounted on the linear guide rail 710; the laser tracking device 500 and the welding device 600 are mounted on the upper surface of the trolley 720. Compared with the transmission device, the linear motion system 700 uses a geared motor plus a rack and pinion drive method, which has higher motion accuracy. During the welding process, a linear telemetry system is used to control the movement of the laser tracking device 500 and the welding device 600.

[0061] It is understandable that the automatic welding system also includes an electrical control cabinet 800 located on one side of the transmission device. On the one hand, the electrical control cabinet 800 is electrically connected to the laser tracking device 500 and the welding device 600 respectively, providing power for the movement of the laser tracking device 500 and the welding device 600. On the other hand, the electrical control cabinet 800 is signal connected to the laser tracking device 500 and the welding device 600 respectively, for controlling the precise movement of the laser tracking device 500 and the welding device 600.

[0062] To facilitate understanding of the technical solution of the automated welding system for full penetration of thick plate fillet welds, a brief description of its welding process is provided:

[0063] Step 1: Taking the welding of the top web of a bridge as an example, the second plate (corrugated plate A) to be bevel D is placed at a predetermined angle at a predetermined position of the first plate (top plate B), and pre-installed by manual spot welding to form the plate to be welded. The weld between corrugated plate A and top plate B is a wavy line.

[0064] Step 2: Transfer the sheet metal to be welded to the processing station of the automatic welding system using a conveying device;

[0065] Step 3: Input the relevant parameters of the wavy weld path C under theoretical conditions into the servo motor 522 and the linear motion system 700. With the cooperation of the telescopic module 520 and the linear motion system 700, the distance between the laser tracking system 530 and the weld is kept consistent or within a predetermined range. The laser tracking system 530 is located within its optimal measurement range, and the position information of the weld path C under actual working conditions can be accurately obtained.

[0066] Step 4: With the cooperation of the six-axis robot and the linear motion system 700, the six-axis robot adjusts the spatial position and attitude of the welding torches 620 on both sides to achieve compensation in the weld seam spatial position. The attitude adjustment of the welding torches 620 ensures that the welding torches 620 are always perpendicular to the weld seam path C on the second plate or maintain a constant angle with the normal vector of the weld seam on the second plate. With the cooperation of the linear motion system 700, the welding torches 620 on both sides of the plate to be welded move along the weld seam at a predetermined rate, and the welding points of the welding torches 620 on both sides are always located at the same position on the weld seam path C, thereby achieving a more perfect welding effect.

[0067] Traditional full-fusion welding generally includes the following steps: Step 1, placing the beveled plate at a predetermined angle on the other half of the plate, and then welding the bevel side; Step 2, manually grinding the bevel on the non-bevel side; Step 3, welding on the manually ground bevel side. Compared to traditional welding processes, for multi-layer, multi-pass deep-penetration welding of thick plates, the welding of the root of the first bevel has particularly strict requirements for tracking. Since traditional processes cannot achieve the welding precision of this application, it is necessary to clean the root of the thick plate weld back. Traditional thick plate fillet welds require manual grinding of the bevel on the non-bevel side using air gouging, which increases processing materials and costs, and has low processing efficiency. However, the automatic welding process in this embodiment not only eliminates the need for grinding the bevel D, significantly saving costs and reducing materials, but also allows for simultaneous welding on both sides, greatly saving 66% of the labor time.

[0068] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A welding method for achieving full penetration of fillet welds in thick plates, characterized in that, The welding method is based on a welding system, which includes: A conveying device suitable for conveying the plates to be welded to the processing station; At least two linear motion systems are respectively disposed on both sides of the plate to be welded and move along the weld direction on the plate to be welded at the same speed; the plate to be welded includes a horizontally placed top plate, a corrugated plate placed on the top plate at a predetermined angle, and a bevel disposed on one side of the corrugated plate. At least two welding devices are located on the linear motion system, respectively; the welding devices include industrial robots respectively mounted on the linear motion system, and welding torches mounted on the output end of the industrial robots and always maintaining a constant distance from the weld and a constant angle with the normal vector of the weld on the corrugated plate. Two laser tracking devices are respectively located on the linear motion system; each laser tracking device includes a column set on one side of the transmission device, a lifting module set on the column, a telescopic module installed on the output end of the lifting module, and a laser tracking system installed on the output end of the telescopic module and whose distance relative to the weld seam is always kept consistent or within a predetermined range. The linear motion system includes: a linear guide rail disposed on one side of the transmission device, and a trolley slidably mounted on the linear guide rail; the laser tracking device and the welding device are mounted on the upper surface of the trolley. The welding method includes: Step 1: Place the beveled corrugated plate at a predetermined angle at a predetermined position on the top plate and pre-install it to form a plate to be welded; the weld path between the corrugated plate and the top plate is a wavy line. Step 2: Transfer the sheet metal to be welded to the processing station of the automatic welding system; Step 3: Input the relevant parameters of the wavy weld path under theoretical conditions into the servo motor and linear motion system of the linear motion module. With the cooperation of the telescopic module and the linear motion system, the distance between the laser tracking system and the weld is kept consistent or within a predetermined range and within the optimal measurement range of the laser tracking system. The position information of the weld path under actual working conditions is obtained through the laser tracking device. Step 4: With the cooperation of the industrial robot and the linear motion system, the industrial robot adjusts the spatial position and posture of the welding torches on both sides to compensate for the spatial position of the weld seam. The welding torch posture is adjusted so that the welding torch is always perpendicular to the weld seam path on the corrugated plate or maintains a constant angle with the normal vector of the weld seam on the corrugated plate. With the cooperation of the linear motion system, the welding torches on both sides of the plate to be welded move along the weld seam at a predetermined speed and the welding points of the welding torches on both sides are always located at the same position on the weld seam path.

2. The welding method for full penetration of thick plate fillet welds according to claim 1, characterized in that, The automatic welding system also includes an electrical control cabinet mounted on the upper surface of the mobile trolley, which is connected to the laser tracking device, the welding device, and the mobile trolley via signal connections.

3. The welding method for full penetration of thick plate fillet welds according to claim 1, characterized in that, The industrial robot has at least 6 degrees of freedom.

4. The welding method for full penetration of thick plate fillet welds according to claim 3, characterized in that, The industrial robot includes: a base; a waist rotation mechanism rotatably mounted on the base; a large arm mechanism rotatably mounted on the waist rotation mechanism; a forearm mechanism rotatably mounted at the other end of the large arm mechanism; a wrist mechanism rotatably mounted at the other end of the forearm mechanism; and an end effector rotatably mounted at the other end of the wrist mechanism for mounting a welding torch.

5. The welding method for full penetration of thick plate fillet welds according to claim 1, characterized in that, The top plate and the corrugated plate are pre-installed together by manual spot welding.

6. The welding method for full penetration of thick plate fillet welds according to claim 1, characterized in that, All welding torches used are deep penetration welding torches.

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