Laser welding device for plate heat exchanger

Abstract

This invention belongs to the technical field of laser welding, specifically relating to a laser welding device for plate heat exchangers. The device includes an X-axis, Y-axis, Z-axis, a welding axis, a laser welding head, and an intelligent welding system. The intelligent welding system is electrically connected to the X-axis, Y-axis, Z-axis, welding axis, and laser welding head. The X-axis, Y-axis, and Z-axis are used to adjust the position of the laser welding head in the X, Y, and Z vectors. The welding axis drives the laser welding head to move left and right to weld the weld seam of the plate heat exchanger. The welding axis includes a housing, a motor, two guide rails, two sliders, a connecting block, a central shaft, and a sleeve block. The motor is fixedly installed on the right side of the housing, and both guide rails are fixedly installed inside the housing. This device solves the problem of inefficiently controlling the smooth movement of the welding torch when welding the weld seam of a plate heat exchanger, which affects the welding quality.

Description

Technical Field

[0001] This invention belongs to the technical field of laser welding, and specifically relates to a laser welding device for plate heat exchangers. Background Technology

[0002] Plate heat exchangers, with their advantages of high heat exchange efficiency and compact structure, are widely used in chemical, HVAC, and refrigeration industries. The sealing and structural connection between their plates rely on welding processes. Laser welding has become the mainstream welding process for plate heat exchangers due to its high energy density and small heat-affected zone, while argon arc welding is suitable for welding thick plates or structural reinforcement parts. Therefore, dual-welding-gun combination welding has become the preferred solution for plate heat exchangers.

[0003] In actual welding processes, ball screws or threaded drives are often used to move the welding torch. These types of drives have low smoothness, which makes it easy for jamming to occur during the transmission process. This jamming can affect the welding quality and also increase the energy consumption of the drive source, such as the high energy consumption of the motor when it is rotating. This increases the operating cost of the welding equipment. These are all problems that need to be solved by those skilled in the art. Therefore, there is an urgent need for a laser welding device that can achieve weld seam tracking while ensuring welding quality. Summary of the Invention

[0004] The purpose of this invention is to provide a laser welding device for plate heat exchangers to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a laser welding device for a plate heat exchanger, comprising an X-axis, a Y-axis, a Z-axis, a welding axis, a laser welding head, and an intelligent welding system, wherein the intelligent welding system is electrically connected to the X-axis, Y-axis, Z-axis, welding axis, and laser welding head respectively; the X-axis, Y-axis, and Z-axis are used to adjust the position of the laser welding head in the X, Y, and Z vectors, and the welding axis is used to drive the laser welding head to move left and right to weld the weld seam of the plate heat exchanger; the welding axis includes a housing, a motor, two guide rails, two sliders, and a connecting... The housing comprises a connecting block, a central shaft, and a sleeve block. The motor is fixedly installed on the right side of the housing. Both guide rails are fixedly installed inside the housing, and two sliders are slidably connected to the two guide rails and fixed to the connecting block via the sliders. The laser welding head is fixedly installed on the connecting block. The central shaft is connected to the output end of the motor and has two opposing V-grooves on its outer surface. The sleeve block is fitted onto the outside of the central shaft, and two rollers are rotatably connected to its inner wall. The rollers are embedded in the V-grooves. Limits are provided at both ends of the sleeve block, and the connecting block is located between the two limits.

[0006] The present invention further explains that the operation steps of the intelligent welding system include: Step S1, system initialization, clamping the plate heat exchanger plates onto the welding worktable, starting the dual-gun welding equipment of laser welding and argon arc welding, and preset welding process parameters, weld position deviation threshold and welding gun switching rules through the human-machine interaction module; Step S2, using a laser vision sensor to collect the contour information of the weld area of ​​the plate heat exchanger, and simultaneously using an arc sensor to collect the electrical signal characteristics of the welding arc, fusing the two types of sensor data to obtain the real-time position coordinates of the weld center; Step S3, comparing the real-time position coordinates of the weld obtained in Step S2 with the preset welding path coordinates, and calculating the translational deviation values ​​in the X-axis, Y-axis directions and the Z-axis... Step S4: Adjust the laser welding head's posture according to the deviation value to compensate for the weld position deviation. At the same time, the sensor's built-in air knife nozzle blows away the smoke and dust in the weld area to ensure detection accuracy. Step S5: If the deviation value is ≤ the preset threshold, maintain the current welding parameters of the welding torch. If the deviation value exceeds the threshold, dynamically adjust the laser power, welding speed, or argon arc welding wire feed speed according to the deviation size. At the same time, execute the dual welding torch switching logic according to the welding requirements of the plate heat exchanger. Step S6: Monitor the deviation value and welding parameters in real time during the welding process. When the deviation value continues to exceed the standard, trigger an alarm and pause welding. The operation will resume after manual intervention. After welding is completed, save the welding data and generate a tracking report.

[0007] The present invention further describes that the right end of the central shaft is provided with a socket and a pin is inserted into the socket. A turntable is provided on the right side of the pin and the two are fixedly connected. The turntable is fixedly connected to the output end of the motor. Guide posts are slidably connected to the front and rear sides of the sleeve, and the left and right ends of the guide posts are fixedly connected to the inner wall of the housing.

[0008] The present invention further illustrates that the sleeve has an annular hole inside, the annular hole is connected to an external liquid pump pipeline, and the rotational connection between the roller and the sleeve is in communication with the inside of the annular hole.

[0009] The present invention further illustrates that a through hole is provided in the middle of the central shaft, and a sliding hole is provided in the middle of the through hole. A sliding rod is slidably connected to the inner wall of the through hole, and a ring is fixedly connected to both the left and right ends of the sliding rod. The inner wall of the ring fits against the outer wall of the central shaft.

[0010] The present invention further explains that when the sleeve block moves to the left or right end, it contacts the inner end of the left or right ring sleeve, respectively.

[0011] The present invention further illustrates that the central shaft includes two half-shafts, and the two half-shafts fit together to form a cylindrical central shaft. The inner wall of each half-shaft is integrally formed with an arc-shaped block, and the arc-shaped block is located in a sliding hole.

[0012] The present invention further illustrates that the outer side of the slide bar has two protrusions integrally formed, and the two protrusions are respectively located on the left and right sides of the arc-shaped block, and the outer wall of the ring is made of elastic material.

[0013] The present invention further illustrates that the surface of the ring on the right side is provided with a U-shaped groove, and the pin is inserted into the U-shaped groove.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The method used in the present invention to drive the laser welding head to move horizontally is smoother than that of ball screw transmission, thread transmission or gear transmission, and there will be no jamming during the movement, thereby improving the welding quality of the weld seam, and also reducing the energy consumption of the motor, playing an energy-saving role and reducing the operating cost of the laser welding device. Furthermore, adjusting the welding speed controls the heat input and ensures the quality of the weld formation. It also affects welding efficiency and joint performance. Excessive speed leads to insufficient heat input, resulting in defects such as incomplete penetration, lack of fusion, and porosity. Conversely, excessive speed leads to excessive heat input, a larger molten pool, burn-through, coarse grains, and potentially excessive deformation of the base material. A suitable speed ensures the weld width, reinforcement height, and penetration depth meet design requirements, forming a smooth and uniform weld. Improper speed prevents issues such as inconsistent weld width, excessively high / low reinforcement height, and undercut. While ensuring welding quality, appropriately increasing the speed can improve welding production efficiency. Simultaneously, adjusting the speed by controlling the motor speed results in dynamic losses during motor speed regulation, and the efficiency of the speed regulation system decreases outside the rated speed range. Maintaining a constant motor speed reduces operating energy consumption and costs. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the welding shaft of the present invention; Figure 3 This is a schematic diagram of the internal structure of the welding shaft of the present invention; Figure 4 This is a cross-sectional view of the internal structure of the welding shaft of the present invention; Figure 5 This is an exploded view of the internal structure of the welding shaft of the present invention; Figure 6 This is a schematic diagram of the central shaft structure of the present invention; In the diagram: 1. X-axis; 2. Y-axis; 3. Z-axis; 4. Welding shaft; 41. Housing; 42. Motor; 43. Connecting block; 44. Sleeve block; 441. Ring hole; 45. Roller; 46. Pin; 47. Turntable; 48. Slide rod; 481. Ring sleeve; 482. Boss; 49. Half shaft; 491. Arc block; 5. Laser welding head. Detailed Implementation

[0016] The following detailed, non-limiting description of the technical solution of the present invention, in conjunction with preferred embodiments and accompanying drawings, is provided. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0017] Please see Figures 1-6 The present invention provides a technical solution: a laser welding device for a plate heat exchanger, comprising an X-axis 1, a Y-axis 2, a Z-axis 3, a welding axis 4, a laser welding head 5, and an intelligent welding system, wherein the intelligent welding system is electrically connected to the X-axis 1, Y-axis 2, Z-axis 3, welding axis 4, and laser welding head 5 respectively; X-axis 1, Y-axis 2, and Z-axis 3 are used to adjust the position of the laser welding head 5 in the X, Y, and Z vectors, while welding axis 4 is used to drive the laser welding head 5 to move left and right to weld the weld seam of the plate heat exchanger. The welding shaft 4 includes a housing 41, a motor 42, two guide rails, two sliders, a connecting block 43, a central shaft, and a sleeve 44. The motor 42 is fixedly installed on the right side of the housing 41. Both guide rails are fixedly installed inside the housing 41, and the two sliders are slidably connected to the two guide rails and fixed to the connecting block 43 through the sliders. The laser welding head 5 is fixedly installed on the connecting block 43. The central shaft is connected to the output end of the motor 42 and has two opposing V-shaped grooves on its outer surface. The sleeve 44 is sleeved on the outside of the central shaft, and two rollers 45 are rotatably connected to its inner wall. The rollers 45 are embedded in the V-shaped grooves. Limits are provided at both ends of the sleeve 44, and the connecting block 43 is located between the two limits. When welding the plate heat exchanger, the initial position of the laser welding head 5 is controlled by X-axis 1, Z-axis 3 and Y-axis 2. The intelligent welding system adjusts the position of the laser welding head 5 until it is aligned with the weld seam of the plate heat exchanger. Then the laser welding head 5 runs to weld the weld seam. At the same time, the welding shaft 4 drives the laser welding head 5 to move horizontally to weld the entire weld seam. The welding shaft 4 drives the laser welding head 5 to move by the operation of the motor 42, which drives the central shaft to rotate. This causes the rollers 45 on the sleeve 44 to roll in the V-groove, allowing the sleeve 44 to move left and right. The sleeve 44, through its limiting mechanism, drives the connecting block 43 to move. The connecting block 43 slides on the guide rail via a slider, providing stability for movement. At the same time, the connecting block 43 drives the laser welding head 5 to move horizontally. This method of driving the laser welding head 5 to move horizontally is smoother than using ball screw drives, threaded drives, or gear drives. There will be no jamming during the movement, thereby improving the welding quality of the weld seam. It also reduces the energy consumption of the motor 42, achieving energy saving and reducing the operating cost of the laser welding device.

[0018] The operation steps of the intelligent welding system include: Step S1: System initialization. Clamp the plate heat exchanger plates onto the welding worktable, start the dual welding gun welding equipment of laser welding and argon arc welding, and preset the welding process parameters, weld position deviation threshold and welding gun switching rules through the human-machine interaction module. Step S2: Use a laser vision sensor to collect the contour information of the weld area of ​​the plate heat exchanger, and at the same time use an arc sensor to collect the electrical signal characteristics of the welding arc. Combine the two types of sensor data to obtain the real-time position coordinates of the weld center. Step S3: Compare the real-time position coordinates of the weld obtained in step S2 with the preset welding path coordinates, and calculate the translational deviation values ​​in the X-axis 1 and Y-axis 2 directions and the height deviation value in the Z-axis 3 direction. Step S4: Adjust the position of the laser welding head 5 according to the deviation value to compensate for the weld position deviation. At the same time, the built-in air knife of the sensor blows away the smoke and dust in the weld area to ensure detection accuracy. Step S5: If the deviation value is less than or equal to the preset threshold, maintain the current welding parameters of the welding torch; if the deviation value exceeds the threshold, dynamically adjust the laser power, welding speed or argon arc welding wire feeding speed according to the deviation size, and execute the dual welding torch switching logic according to the welding requirements of the plate heat exchanger. Step S6: Monitor the deviation value and welding parameters in real time during the welding process. When the deviation value continues to exceed the standard, trigger an alarm and suspend welding. The operation will resume after manual intervention. After welding is completed, save the welding data and generate a tracking report. By adopting a fusion detection method combining laser vision and arc sensing, and incorporating a dustproof design with a built-in air knife tip in the sensor, the anti-interference capability and accuracy of weld seam detection are improved. It adapts to high-temperature and dusty welding environments. The switching and parameter adaptation logic is designed for the process characteristics of dual welding guns, taking into account the different needs of laser precision welding and argon arc welding, and adapting to the welding requirements of different parts. The servo-driven rapid posture adjustment and dynamic parameter matching increase the welding speed by more than 2 times, significantly improving production efficiency and first-pass yield. By integrating temperature monitoring and alarm mechanisms, the lifespan of the sensor is extended, ensuring the stability of the welding process.

[0019] A socket is provided at the right end of the central shaft, and a pin 46 is inserted into the socket. A turntable 47 is provided on the right side of the pin 46, and the two are fixedly connected. The turntable 47 is fixedly connected to the output end of the motor 42. Guide posts are slidably connected to the front and rear sides of the sleeve block 44, and the left and right ends of the guide posts are fixedly connected to the inner wall of the housing 41. The motor 42 runs, driving the turntable 47 to rotate. The turntable 47 drives the central shaft to rotate through the pin 46, thereby improving the connection strength between the two and ensuring the stability of the laser welding head 5 movement. At the same time, the sleeve 44 slides along the guide post, further improving the stability of the welding process and fully avoiding vibration during the welding process that could damage the weld or the laser welding equipment.

[0020] The sleeve 44 has an annular hole 441 inside, which is connected to the external liquid pump pipeline, and the rotating connection between the roller 45 and the sleeve 44 is connected to the inside of the annular hole 441. Before or during welding, if it is necessary to adjust the welding speed, liquid is injected into the annular hole 441 through an external liquid pump. The hydraulic pressure drives the roller 45 to move, making the roller 45 more tightly connected to the inner wall of the V-groove. This controls the friction between the roller 45 and the V-groove, thereby adjusting the movement speed of the sleeve 44. This controls the movement speed of the laser welding head 5, adjusts the welding weld movement speed, controls the welding heat input, ensures the weld formation quality, and affects welding efficiency and joint performance. It avoids excessively fast movement speed, which leads to insufficient heat input and defects such as incomplete penetration, incomplete fusion, and porosity. It also prevents excessively slow movement speed, which leads to excessive heat input, a larger molten pool, weld burn-through, coarse grains, and excessive welding deformation of the base material. A suitable movement speed allows the weld width, reinforcement height, and penetration depth to meet design requirements, forming a smooth and uniform weld. It prevents problems such as uneven weld width, excessively high / low reinforcement height, and undercut caused by improper movement speed. Under the premise of ensuring welding quality, appropriately increasing the movement speed can improve welding production efficiency. At the same time, the speed of the motor 42 is adjusted by controlling its rotational speed. This causes dynamic losses during the speed adjustment process of the motor 42, and the efficiency of the speed adjustment system will decrease in the non-rated speed range. This keeps the speed of the motor 42 constant, thereby reducing operating energy consumption and reducing costs.

[0021] A through hole is provided in the middle of the central shaft, and a sliding hole is provided in the middle of the through hole. A sliding rod 48 is slidably connected to the inner wall of the through hole. Both ends of the sliding rod 48 are fixedly connected to a ring 481. The inner wall of the ring 481 is in contact with the outer wall of the central shaft.

[0022] When the sleeve 44 moves to the left or right end, it contacts the inner end of the left ring 481 or the right ring 481 respectively. When the sleeve 44 moves to the left or right end, it contacts the ring 481 and is squeezed against the ring 481. Through the reaction force, the laser welding head 5 is decelerated when it moves to the end of the weld, thus creating a pause. This operation is called arc start pause and arc end pause. Its core function is to ensure the penetration depth and forming quality of the weld at the beginning and end, and to avoid defects.

[0023] The central shaft includes two half-shafts 49, which fit together to form a cylindrical central shaft. The inner walls of the half-shafts 49 are integrally formed with arc-shaped blocks 491, which are located inside the sliding holes.

[0024] The outer side of the slide bar 48 has two protrusions 482 integrally formed, and the two protrusions 482 are located on the left and right sides of the arc block 491 respectively. The outer wall of the ring 481 is made of elastic material. When the sleeve block 44 and the ring sleeve 481 are pressed against each other, the ring sleeve 481 moves to the left or right, thereby driving the slide rod 48 to move to the left or right. The slide rod 48 drives the boss 482 and the arc block 491 to press against each other, thereby spreading the two half shafts 49 apart. This can relatively increase the arc angle of the left or right end of the V-groove, thereby relatively increasing the pause time. However, the pause time will not be too long, so that the heat source can fully heat the base material to form a stable molten pool, ensuring good fusion between the weld at the arc start end and the base material. The arc end pause can supplement the heat input, allowing the molten pool metal to fully fill the arc crater. If necessary, the arc end current function of the welding machine can be used to further optimize the weld quality at the arc end. Meanwhile, by spreading the two half-shafts 49 apart, the squeezing force between the roller 45 and the V-groove is further increased, which can further buffer the laser welding head 5 from being subjected to strong inertial influence, thereby preventing damage to the internal electronic components. Furthermore, the sleeve block 44 moves back and disengages from the ring sleeve 481, causing the arc block 491 to disengage from the boss 482. Through the elastic deformation and reset of the ring sleeve 481, the two half-shafts 49 are re-fitted, reducing the friction between the roller 45 and the V-groove, thus making the welding process smoother.

[0025] The surface of the right ring 481 is provided with a U-shaped groove, and the pin 46 is inserted into the U-shaped groove; By setting a U-shaped groove, the ring 481 can move without being restricted by the pin 46 and without affecting the rotation of the central shaft.

[0026] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser welding device for a plate heat exchanger, comprising an X-axis (1), a Y-axis (2), a Z-axis (3), a welding axis (4), a laser welding head (5), and an intelligent welding system, characterized in that: The intelligent welding system is electrically connected to the X-axis (1), Y-axis (2), Z-axis (3), welding axis (4) and laser welding head (5), respectively; The X-axis (1), Y-axis (2) and Z-axis (3) are used to adjust the position of the laser welding head (5) on the X, Y and Z vectors, and the welding axis (4) is used to drive the laser welding head (5) to move left and right to weld the weld seam of the plate heat exchanger. The welding shaft (4) includes a housing (41), a motor (42), two guide rails, two sliders, a connecting block (43), a central shaft, and a sleeve (44). The motor (42) is fixedly installed on the right side of the housing (41). The two guide rails are fixedly installed inside the housing (41), and the two sliders are slidably connected to the two guide rails and fixed to the connecting block (43) through the sliders. The laser welding head (5) is fixedly installed on the connecting block (43). The central shaft is connected to the output end of the motor (42) and has two opposing V-shaped grooves on its outer surface. The sleeve (44) is sleeved on the outside of the central shaft, and two rollers (45) are rotatably connected to its inner wall. The rollers (45) are embedded in the V-shaped grooves. Limits are provided at both ends of the sleeve (44), and the connecting block (43) is located between the two limits. The right end of the central shaft is provided with a socket and a pin (46) is inserted into the socket. A turntable (47) is provided on the right side of the pin (46) and the two are fixedly connected. The turntable (47) is fixedly connected to the output end of the motor (42). The front and rear sides of the sleeve (44) are slidably connected with guide posts, and the left and right ends of the guide posts are fixedly connected to the inner wall of the housing (41).

2. The laser welding device for a plate heat exchanger according to claim 1, characterized in that: The operation steps of the intelligent welding system include: Step S1: System initialization. Clamp the plate heat exchanger plates onto the welding worktable, start the dual welding gun welding equipment of laser welding and argon arc welding, and preset the welding process parameters, weld position deviation threshold and welding gun switching rules through the human-machine interaction module. Step S2: Use a laser vision sensor to collect the contour information of the weld area of ​​the plate heat exchanger, and at the same time use an arc sensor to collect the electrical signal characteristics of the welding arc. Combine the two types of sensor data to obtain the real-time position coordinates of the weld center. Step S3: Compare the real-time position coordinates of the weld obtained in step S2 with the preset welding path coordinates, and calculate the translational deviation values ​​in the X-axis (1) and Y-axis (2) directions and the height deviation value in the Z-axis (3) direction. Step S4: Adjust the position of the laser welding head (5) according to the deviation value to compensate for the weld position deviation. At the same time, the built-in air knife of the sensor blows away the smoke and dust in the weld area to ensure detection accuracy. Step S5: If the deviation value is less than or equal to the preset threshold, maintain the current welding parameters of the welding torch; if the deviation value exceeds the threshold, dynamically adjust the laser power, welding speed or argon arc welding wire feeding speed according to the deviation size, and execute the dual welding torch switching logic according to the welding requirements of the plate heat exchanger. Step S6: Monitor the deviation value and welding parameters in real time during the welding process. When the deviation value continues to exceed the standard, trigger an alarm and suspend welding. The operation will resume after manual intervention. After the welding is completed, save the welding data and generate a tracking report.

3. The laser welding apparatus for a plate heat exchanger according to claim 1, characterized in that: The sleeve (44) has an annular hole (441) inside, which is connected to an external liquid pump pipeline, and the rotating connection between the roller (45) and the sleeve (44) is connected to the inside of the annular hole (441).

4. The laser welding apparatus for a plate heat exchanger according to claim 3, characterized in that: The central shaft has a through hole in the middle, and a sliding hole in the middle of the through hole. A sliding rod (48) is slidably connected to the inner wall of the through hole. Both ends of the sliding rod (48) are fixedly connected to a ring sleeve (481). The inner wall of the ring sleeve (481) is in contact with the outer wall of the central shaft.

5. The laser welding apparatus for a plate heat exchanger according to claim 4, characterized in that: When the sleeve (44) moves to the left or right end, it contacts the inner end of the left ring (481) or the right ring (481) respectively.

6. The laser welding apparatus for a plate heat exchanger according to claim 5, characterized in that: The central shaft includes two half shafts (49), and the two half shafts (49) fit together to form a cylindrical central shaft. The inner wall of each half shaft (49) is integrally formed with an arc-shaped block (491), and the arc-shaped block (491) is located in the sliding hole.

7. The laser welding apparatus for a plate heat exchanger according to claim 6, characterized in that: The outer side of the slide bar (48) has two protrusions (482) integrally formed, and the two protrusions (482) are located on the left and right sides of the arc block (491) respectively. The outer wall of the ring (481) is made of elastic material.

8. The laser welding apparatus for a plate heat exchanger according to claim 7, characterized in that: The surface of the ring (481) on the right side is provided with a U-shaped groove, and the pin (46) is inserted into the U-shaped groove.

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