Plate welding assembly tool and welding method thereof

Abstract

The invention discloses a plate welding assembly tool and a welding method thereof. The tool comprises a plane supporting platform and a support, wherein the support is located above the supporting platform and used for fixing a truss beam of a pressing mechanism; the pressing mechanism at least comprises two groups of telescopic air cylinders or oil cylinders; a strip-shaped opening is formed in the middle of the steel structure plane pressing plate; a slotted copper liner of which the middle part is provided with a strip-shaped groove; the tool is used for butt seam welding of a plane to-be-welded plate. According to the tool, non-rigid pressing plate connection is adopted, an air cylinder piston rod is only in surface contact with the pressing plate, and the problem of insufficient local pressing caused by traditional rigid connection is solved; the shape is controlled by adopting the slotted copper gasket, a groove matching structure is arranged, and the qualification rate is greatly improved in combination with the high thermal conductivity of the gasket; the tool can be automatically matched, is matched with the repeated positioning precision of a robot welding system, is simple in structure and convenient and fast to operate, and can guarantee the assembly precision, the pressing effect and the back face forming quality at the same time.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, and more particularly to the field of welding tooling design technology. Specifically, it relates to an assembly device and welding method for sheet metal in a single-sided welding double-sided forming process. Background Technology

[0002] Current conventional sheet metal welding uses general-purpose fixtures and pressure plates. After welding one side, the workpiece is flipped 180 degrees before welding the other side. This method requires secondary positioning and welding, resulting in low production efficiency. Furthermore, flipping large workpieces poses safety risks and can cause deformation and quality issues.

[0003] Currently, a single-sided welding with double-sided forming technology has been developed for welding medium and heavy plates. This technology is highly efficient, requiring only welding on one side of the plate to simultaneously create uniform and full weld beads on both the front and back sides. The successful implementation of this technology heavily relies on the precision of the plate assembly before welding, reliable fixation of the plates during welding, and effective control of the weld bead formation on the back side.

[0004] In existing technologies, simple clamps or pressure blocks are often used for fixing, which presents several technical problems: Assembly accuracy is difficult to guarantee: ordinary clamps cannot ensure the uniformity of the weld root gap and the centering of the bevel, easily leading to defects such as weld misalignment, incomplete penetration, or poor back-side formation; The clamping effect is unsatisfactory: uneven or improper clamping force can easily deform or misalign the plate during welding, affecting the forming quality; Back-side formation is not guaranteed: conventional tooling lacks a dedicated mechanism for auxiliary control of the weld back-side formation, and the quality of the back-side weld depends entirely on the self-forming of the welding material during melting. The weld gap limits the maximum welding current, easily resulting in incomplete penetration or excessively high back-side welds with poor consistency; Automation compatibility is poor: for robotic welding, there is a lack of dedicated tooling capable of precise positioning, rapid clamping, and ensuring back-side formation quality, limiting the efficiency and quality of automated welding. Summary of the Invention

[0005] This invention discloses a plate welding assembly fixture and its welding method to address the shortcomings of existing technologies. The purpose of this invention is to provide a single-sided welding and double-sided forming dedicated welding assembly fixture and its welding method that is simple in structure, easy to operate, and can simultaneously ensure assembly accuracy, clamping effect, and back-side forming quality.

[0006] This invention is achieved through the following technical solution:

[0007] A plate welding assembly tooling for butt welding of flat plates, characterized in that it includes a bracket, a clamping mechanism, a pressure plate, and a slotted copper gasket.

[0008] The support frame is a steel truss that has undergone aging treatment to eliminate internal stress, and has at least one planar support platform and a truss beam located above the support platform for fixing the clamping mechanism;

[0009] The clamping mechanism includes at least two sets of retractable cylinders or hydraulic cylinders, each retractable cylinder or hydraulic cylinder being symmetrically arranged relative to the center of the bracket, for clamping and fixing the pressure plate.

[0010] The pressure plate is an independent steel truss box-shaped planar beam. A long strip opening is provided in the middle of the planar beam to match the weld of the plate. The pressure plate is placed on the planar support platform of the bracket to press and fix the plate to be welded and place the weld of the plate to be welded in the center of the opening to allow the welding gun to weld freely.

[0011] The slotted copper pad is an independent flat pad made of copper material with thermal conductivity. The flat pad has a long groove in the middle that matches the weld seam of the plate to be welded. The slotted copper pad is placed on the surface of the flat support platform of the bracket, below the plate to be welded, and the weld seam of the plate to be welded is placed above the long groove.

[0012] Furthermore, the thickness of the slotted copper backing is 5-10mm, and the cross-sectional shape of the elongated groove in the middle is arc-shaped or rectangular, matching the expected back weld bead shape of the weld seam of the plate to be welded.

[0013] The width of the elongated groove is not less than 1.2 times the gap at the root of the weld seam of the plate to be welded, and the depth is 0.8 to 2 mm; the flatness error of the slotted copper pad is not greater than 0.1 mm / m, and the back of the plate to be welded is tightly fitted with the slotted copper pad without gaps during welding.

[0014] Furthermore, the pressure plate is a box-shaped welded structure; the bottom surface of the pressure plate is adapted to the contour of the upper surface of the plate to be welded, and the flatness error of the bottom surface is not greater than 0.2mm / m.

[0015] The width of the elongated opening is adapted to the operating range of the robot or manual welding gun, and the opening length is not less than 1.1 times the weld length of the plate to be welded.

[0016] Furthermore, the support structure consists of a steel truss support plane platform and suspended truss beams located at both ends of the steel truss. Two sets of air cylinders or hydraulic cylinders of the clamping mechanism are suspended and fixed on the truss beams to clamp and fix the pressure plate on the steel truss support plane platform.

[0017] Furthermore, the aging treatment of the support is artificial aging treatment, and the treatment conditions include: temperature 200-300℃, heat preservation for 2-4 hours; the horizontality error of the planar support platform is no greater than 0.1mm / m, the verticality error between the suspended truss beam and the planar support platform is no greater than 0.1mm / m; and the symmetry error of the axes of the two sets of cylinders or hydraulic cylinders relative to the central plane of the support is no greater than 0.2mm.

[0018] Furthermore, the planar support platform is provided with at least two detachable positioning pins. The spacing between the positioning pins is adapted to the length of the plate to be welded, and is used for positioning when assembling the plate to be welded. The coaxiality error of the positioning pins is not greater than 0.1mm.

[0019] The present invention further discloses a plate welding process for tooling using the above-mentioned plate welding assembly, comprising the following steps:

[0020] Step 1: Manually assemble the two plates to be welded on the flat support platform, and use locating pins to achieve lateral positioning, ensuring that the bevels of the plates to be welded are aligned and the gap at the root of the weld meets the welding process requirements; precisely place the slotted copper backing under the back of the weld, aligning the center of its long groove with the center of the bevel, with an alignment error of no more than 0.2mm;

[0021] Step 2: Place the pressure plate on top of the assembled plates to be welded, and ensure that the center line of the long strip opening of the pressure plate coincides with the center line of the weld seam of the plate to be welded below, with an overlap error of no more than 0.1mm;

[0022] Step 3: Operate the manual switch to control the two sets of clamping mechanisms to extend synchronously at the same speed, so that the piston rod presses down evenly against the pressure plate. The pressure plate stably presses the workpiece to be welded onto the flat support platform, and ensures that the back of the workpiece to be welded is in close contact with the slotted copper backing, maintaining a 100% fit.

[0023] Step 4: The weld seam is welded by a manual or robotic welding torch through the long strip opening of the pressure plate; during the welding process, the molten metal is supported, shaped and accelerated cooled by the groove of the slotted copper backing, and after cooling, it forms a weld bead that is full on the front and uniformly shaped on the back.

[0024] Step 5: After welding is completed, operate the switch to retract the clamping mechanism synchronously, manually remove the pressure plate, and take off the welded plate to complete the welding.

[0025] The welding assembly tooling of this invention adopts robotic automatic welding technology and single-sided welding double-sided forming technology. When assembling sheet metal parts, the back of the weld is tightly bonded to the copper backing, the two sides of the weld are flush and have a certain pressure, ensuring that the back of the weldment does not detach from the copper backing during the welding process, realizing one-time assembly welding and forming, eliminating the need for flipping and secondary welding, and greatly improving production efficiency.

[0026] This invention provides a specialized welding assembly fixture that integrates assembly, clamping, and back-side forming control. A pressure plate with a precise opening ensures welding torch alignment, a cylinder provides stable clamping force, and a freely movable pressure plate with a non-rigid connection to the cylinder adapts to the workpiece surface. A liner with a specific groove, such as a copper liner groove, is placed below the back of the workpiece weld to support the molten weld pool, thereby precisely controlling the formation of the back-side weld bead.

[0027] The welding assembly tooling of this invention is designed for the splicing welding process of the web plate and cover plate of the box girder. When using single-sided welding with double-sided forming, it is used in conjunction with a robotic welding system to ensure the quality of the weld and the appearance of the formed weld. This enables high-quality and high-efficiency welding of the girder plates with single-sided welding with double-sided forming, replacing the original double-sided welding process that requires flipping.

[0028] The application of this invention's tooling significantly improves welding quality: Forced centering of the weld seam through the pressure plate opening, combined with controlled forming using a copper backing, effectively avoids defects such as weld misalignment, incomplete penetration, and poor back-side forming, resulting in consistent and stable weld quality. This invention's tooling is simple and efficient to operate: Pneumatic clamping and one-button operation enable fast clamping, greatly improving production efficiency, making it particularly suitable for mass production. This invention's tooling is highly adaptable: The free-state connection design between the pressure plate and the cylinder reduces the requirement for workpiece surface flatness, improving adaptability. This invention's tooling facilitates automation: Its regular structure makes it easy to integrate with robotic welding systems for automated welding. This invention's tooling has a simple and reliable structure: The main components are welded parts and standard pneumatic components, resulting in low manufacturing costs, high rigidity, and long service life.

[0029] The tooling of this invention adopts a non-rigid pressure plate connection: the cylinder piston rod and the pressure plate only have surface contact, and the pressure plate can be slightly adjusted with an adjustment range of ±1mm to adapt to the unevenness of the workpiece surface and solve the problem of insufficient local clamping caused by traditional rigid connection.

[0030] The tooling of this invention uses slotted copper backing for shape control: by matching the groove size with the weld design, such as arc-shaped grooves corresponding to corner welds and rectangular grooves corresponding to butt welds, combined with the high thermal conductivity of copper, the weld bead height on the back side is controlled at 1-2mm, and the pass rate is increased to over 99%.

[0031] The tooling of this invention can be automatically adapted: the overall positioning accuracy of the tooling is ±0.2mm, which matches the repeatability of the robot welding system, enabling 24-hour continuous automated welding. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the assembly forming tooling of the present invention.

[0033] Figure 2This is a schematic diagram of the disassembly of the forming tooling components of the present invention.

[0034] Figure 3 This is a schematic diagram of the assembly forming tooling bracket of the present invention.

[0035] Figure 4 This is a schematic diagram of the anti-deformation pressure plate of the forming tooling assembly of the present invention.

[0036] Figure 5 This is a schematic diagram of the slotted copper liner of the forming tooling of the present invention.

[0037] In the diagram, 1 is the bracket, 2 is the cylinder, 3 is the pressure plate, 4 is the slotted copper gasket, and 5 is the welded plate. Specific Implementation

[0038] The present invention will be further described below with reference to specific embodiments. These specific embodiments are further explanations of the principles of the present invention and are not intended to limit the present invention in any way. Any technology that is the same as or similar to the present invention does not exceed the scope of protection of the present invention.

[0039] The following description, in conjunction with the accompanying drawings, illustrates this embodiment.

[0040] As shown in the figure, the welding assembly tooling consists of a bracket, a pressure plate, a cylinder, and a slotted copper gasket.

[0041] Support frame: As the basic frame, it is welded from structural steel and undergoes aging treatment to eliminate internal stress, ensuring the levelness of its mounting surface and the verticality and parallelism of key parts, providing a stable reference for the entire tooling.

[0042] In this embodiment, the support structure consists of a steel truss support plane platform and suspended truss beams located at both ends of the steel truss. Two sets of air cylinders or hydraulic cylinders of the clamping mechanism are suspended and fixed on the truss beams to clamp and fix the pressure plate on the steel truss support plane platform.

[0043] The aging treatment of the bracket is artificial aging, specifically at a temperature of 200-300℃ for 2-4 hours, to fully eliminate welding internal stress; the horizontal error of the planar support platform is no greater than 0.1mm / m, and the vertical error between the suspended truss beam and the planar support platform is no greater than 0.1mm / m; the symmetry error of the axes of the two sets of cylinders or hydraulic cylinders relative to the center plane of the bracket is no greater than 0.2mm, ensuring symmetrical distribution of clamping force; the planar support platform is equipped with at least two detachable positioning pins, the spacing of which is adapted to the length of the welded plates, for lateral positioning during assembly of the welded plates, and the coaxiality error of the positioning pins is no greater than 0.1mm.

[0044] Cylinders: Preferably, two symmetrically arranged cylinders are fixed to a bracket. Their operation is controlled by an external air source and a manual switch. The function of the cylinders is to provide stable and controllable downward pressure.

[0045] The pressure plate is a box-beam structure made of welded steel plates. The bottom shape of the box beam matches the upper surface of the welded plates, with a long, narrow opening in the center. The width of this opening is precisely designed to ensure that the welding range of the welding torch, especially the robotic welding torch, is covered. In this embodiment, the opening is no larger than 1 inch; sufficient space is also provided for the movement of the welding torch. The box-beam pressure plate and the piston rod of the cylinder are in a non-rigid connection, meaning the cylinder piston rod directly presses against the upper surface of the pressure plate without being fixed by screws, pins, etc. This design allows the pressure plate to adapt to minor unevenness of the workpiece surface during clamping, resulting in a more uniform distribution of clamping force. The box-beam pressure plate structure ensures that the center of the pressure plate presses against the welded plates, and when the two ends are pressed down by the cylinder, it can withstand a large downward force with minimal deflection, thus ensuring that the steel plates on both sides of the weld remain tightly against the copper backing during the welding process.

[0046] In this embodiment, the pressure plate is made of Q235 or higher strength structural steel; the bottom surface of the pressure plate matches the contour of the upper surface of the welded plate, and the flatness error of the bottom surface is no more than 0.2mm / m; the width of the elongated opening is 15-26mm, which is suitable for the operating range of the robot or manual welding gun, and the opening length is no less than 1.1 times the weld length of the plate to be welded; the piston rod of the cylinder or oil cylinder in the pressure mechanism is non-rigidly connected to the pressure plate, and the end face of the piston rod only contacts the upper surface of the pressure plate, without screws, pins or other fixed connecting parts, so that the pressure plate can adapt to the slight unevenness of the surface of the workpiece to be welded; under the rated working pressure of 0.4-0.6MPa of the pressure mechanism, the mid-span deflection of the pressure plate is no more than 0.5mm, ensuring that the welded plates on both sides of the weld are evenly stressed and tightly attached to the slotted copper backing.

[0047] Grooved copper backing: Made of thermally conductive copper, it is placed on a tooling table directly below the bevel to be welded on the workpiece. The copper backing has arc-shaped or rectangular grooves machined onto it to match the expected shape of the back weld bead on the workpiece. These grooves serve to support, shape, and accelerate cooling during welding. The thickness of the grooved copper backing is 5–10 mm.

[0048] The width of the long groove of the slotted copper pad is not less than 1.2 times the gap at the root of the weld seam of the welded plates, and the depth is 0.8 to 2 mm; the flatness error of the slotted copper pad is not greater than 0.1 mm / m, to ensure that the back of the plate and the slotted copper pad are tightly fitted together without gaps during the welding process.

[0049] The welding process is as follows:

[0050] Step 1: Manually assemble the two plates to be welded on the flat support platform, and use locating pins to achieve lateral positioning, ensuring that the bevels of the plates to be welded are aligned and the gap at the root of the weld meets the welding process requirements; precisely place the slotted copper backing under the back of the weld, aligning the center of its long groove with the center of the bevel, with an alignment error of no more than 0.2mm;

[0051] Step 2: Place the pressure plate on top of the assembled plates to be welded, and ensure that the center line of the long strip opening of the pressure plate coincides with the center line of the weld seam of the plate to be welded below, with an overlap error of no more than 0.1mm;

[0052] Step 3: Operate the manual switch to control the two sets of clamping mechanisms to extend synchronously at the same speed, so that the piston rod presses down evenly against the pressure plate. The pressure plate stably presses the workpiece to be welded onto the flat support platform, and ensures that the back of the workpiece to be welded is in close contact with the slotted copper backing, maintaining a 100% fit.

[0053] Step 4: The weld seam is welded by a manual or robotic welding torch through the long strip opening of the pressure plate; during the welding process, the molten metal is supported, shaped and accelerated cooled by the groove of the slotted copper backing, and after cooling, it forms a weld bead that is full on the front and uniformly shaped on the back.

[0054] Step 5: After welding is completed, operate the switch to retract the clamping mechanism synchronously, manually remove the pressure plate, and take off the welded plate to complete the welding.

[0055] The welding fixture drive device of this invention is not limited to a pneumatic cylinder, but can also use a linear actuator such as a hydraulic cylinder or an electric actuator. The liner material is not limited to copper, but can also be other materials with good thermal conductivity and that do not easily adhere to the molten metal.

[0056] This invention integrates assembly, clamping, and back-side forming control into one unit. It uses a pressure plate with a precise opening to ensure the welding torch is centered, a cylinder to provide stable clamping force, and a freely placement pressure plate and a non-rigid connection design with the cylinder to adapt to the workpiece surface. A pad with a specific groove is set below the back of the workpiece weld. In this embodiment, a copper pad is used. The groove supports the weld pool, thereby precisely controlling the forming of the back-side weld.

Claims

1. A plate welding assembly fixture for butt welding of flat plates, characterized in that: Includes bracket, clamping mechanism, pressure plate and slotted copper pad; The support frame is a steel truss that has undergone aging treatment to eliminate internal stress, and has at least one planar support platform and a truss beam located above the support platform for fixing the clamping mechanism; The clamping mechanism includes at least two sets of retractable cylinders or hydraulic cylinders, each retractable cylinder or hydraulic cylinder being symmetrically arranged relative to the center of the bracket, for clamping and fixing the pressure plate. The pressure plate is an independent steel truss box-shaped planar beam. A long strip opening is provided in the middle of the planar beam to match the weld of the plate. The pressure plate is placed on the planar support platform of the bracket to press and fix the plate to be welded and place the weld of the plate to be welded in the center of the opening to allow the welding gun to weld freely. The slotted copper pad is an independent flat pad made of copper material with thermal conductivity. The flat pad has a long groove in the middle that matches the weld seam of the plate to be welded. The slotted copper pad is placed on the surface of the flat support platform of the bracket, below the plate to be welded, and the weld seam of the plate to be welded is placed above the long groove.

2. The plate welding assembly tooling according to claim 1, characterized in that: The thickness of the slotted copper backing is 5-10mm, and the cross-sectional shape of the elongated groove in the middle is arc-shaped or rectangular, matching the expected back weld shape of the weld seam of the plate to be welded.

3. The plate welding assembly tooling according to claim 2, characterized in that: The width of the elongated groove is not less than 1.2 times the gap at the root of the weld seam of the plate to be welded, and the depth is 0.8 to 2 mm; the flatness error of the slotted copper pad is not greater than 0.1 mm / m, and the back of the plate to be welded is tightly fitted with the slotted copper pad without gaps during welding.

4. The plate welding assembly tooling according to claim 2, characterized in that: The pressure plate is a box-shaped welded structure; the bottom surface of the pressure plate is adapted to the contour of the upper surface of the plate to be welded, and the flatness error of the bottom surface is not greater than 0.2mm / m.

5. The plate welding assembly tooling according to claim 4, characterized in that: The width of the elongated opening is adapted to the operating range of the robot or manual welding gun, and the opening length is not less than 1.1 times the weld length of the plate to be welded.

6. The plate welding assembly tooling according to any one of claims 1 to 5, characterized in that: The support consists of a steel truss support plane platform and suspended truss beams set at both ends of the steel truss. Two sets of air cylinders or oil cylinders of the clamping mechanism are suspended and fixed on the truss beams to clamp and fix the pressure plate on the steel truss support plane platform.

7. The plate welding assembly tooling according to claim 6, characterized in that: The aging treatment of the support is artificial aging treatment, and the treatment conditions include: temperature 200-300℃, heat preservation for 2-4 hours; the horizontality error of the planar support platform is no greater than 0.1mm / m, the verticality error between the suspended truss beam and the planar support platform is no greater than 0.1mm / m; the symmetry error of the axes of the two sets of cylinders or oil cylinders relative to the central plane of the support is no greater than 0.2mm.

8. The plate welding assembly tooling according to claim 6, characterized in that: The planar support platform is provided with at least two detachable positioning pins. The spacing between the positioning pins is adapted to the length of the plate to be welded and is used for positioning when assembling the plate to be welded. The coaxiality error of the positioning pins is no more than 0.1mm.

9. A plate welding assembly process, characterized in that: The plate welding assembly tooling according to any one of claims 1 to 8 includes the following steps: Step 1: Manually assemble the two plates to be welded on the flat support platform, and use locating pins to achieve lateral positioning, ensuring that the bevels of the plates to be welded are aligned and the gap at the root of the weld meets the welding process requirements; precisely place the slotted copper backing under the back of the weld, aligning the center of its long groove with the center of the bevel, with an alignment error of no more than 0.2mm; Step 2: Place the pressure plate on top of the assembled plates to be welded, and ensure that the center line of the long strip opening of the pressure plate coincides with the center line of the weld seam of the plate to be welded below, with an overlap error of no more than 0.1mm; Step 3: Operate the manual switch to control the two sets of clamping mechanisms to extend synchronously at the same speed, so that the piston rod presses down evenly against the pressure plate. The pressure plate stably presses the workpiece to be welded onto the flat support platform, and ensures that the back of the workpiece to be welded is in close contact with the slotted copper backing, maintaining a 100% fit. Step 4: The weld seam is welded by a manual or robotic welding torch through the long strip opening of the pressure plate; during the welding process, the molten metal is supported, shaped and accelerated cooled by the groove of the slotted copper backing, and after cooling, it forms a weld bead that is full on the front and uniformly shaped on the back. Step 5: After welding is completed, operate the switch to retract the clamping mechanism synchronously, manually remove the pressure plate, and take off the welded plate to complete the welding.

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