A multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device and working method thereof

Abstract

The present invention discloses a multi-degree-of-freedom ultrasound-assisted laser cladding remanufacturing device and a working method thereof, which belongs to the field of laser cladding, and comprises a workbench, a workpiece to be processed arranged on the top of the workbench via a positioning mechanism, a laser cladding mechanism erected above the workpiece to be processed, and a focusing ultrasonic vibration mechanism symmetrically arranged on both sides of the laser cladding mechanism via a multi-degree-of-freedom variable angle clamping mechanism, wherein the focused ultrasound emitted by the focusing ultrasonic vibration mechanism is aligned with the cladding area of ​​the laser cladding mechanism. The multi-degree-of-freedom ultrasound-assisted laser cladding remanufacturing device and the working method thereof are adopted, and high-intensity focusing of ultrasound waves is achieved through a multi-stage focusing method, and ultrasonic vibrations can be uniformly applied during laser irradiation, thereby effectively reducing defects such as cracks and pores, and improving the processing quality and efficiency of laser cladding remanufacturing.

Description

Technical Field

[0001] The present invention relates to the technical field of laser cladding, and in particular to a multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device and a working method thereof. Background Art

[0002] As a cutting-edge surface modification technology, laser cladding technology has shown broad application prospects in many industries due to its unique advantages. By using high-energy laser beams, it can accurately clad specific materials on the surface of the substrate, achieving local addition, repair or reconstruction of materials. In particular, the application of laser cladding technology is particularly prominent in the fields of aerospace, automobile manufacturing, building materials and energy.

[0003] Laser cladding technology has technical characteristics and advantages:

[0004] 1. Efficient and precise: Laser cladding technology can achieve highly precise control of materials, whether adding or repairing, it can achieve the desired effect;

[0005] 2. Flexibility and innovation: Combined with additive manufacturing technology, laser cladding remanufacturing technology demonstrates great flexibility and innovation capabilities;

[0006] 3. Environmental protection and economy: Through remanufacturing technology, not only can damaged or aging parts be repaired, but the service life of the equipment can also be significantly extended, a large amount of materials and precious metals can be saved, and production costs can be reduced.

[0007] With the above advantages, it has the following application examples:

[0008] 1. Surface strengthening: In mining machinery, petrochemical, electric power and other industries, many key components are worn out due to long-term use. Through laser cladding technology, a layer of high-performance alloy material can be formed on the surface of these components to improve their surface hardness and wear resistance and extend their service life;

[0009] 2. Repair and remanufacturing: For workpieces that have failed due to wear or other reasons, laser cladding technology can repair the surface and improve performance, restoring them to or even exceeding their original state.

[0010] However, laser cladding technology also faces the following challenges:

[0011] 1. Cracks and pores: During the cladding process, rapid cooling and high temperature gradients can easily lead to cracks and pores. These problems will affect the quality of the cladding layer and even damage the performance of the base material.

[0012] 2. Limitations of ultrasonic vibration-assisted technology: Although the existing ultrasonic vibration-assisted laser cladding technology has improved the quality of the cladding layer to a certain extent, it still has problems such as insufficient degrees of freedom, low ultrasonic energy transfer efficiency, poor focusing effect and uneven ultrasonic application, which limits the widespread application of the technology. Summary of the invention

[0013] The purpose of the present invention is to provide a multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device and a working method thereof to solve the above-mentioned technical problems.

[0014] To achieve the above-mentioned objectives, the present invention provides a multi-degree-of-freedom ultrasound-assisted laser cladding remanufacturing device, comprising a workbench, a workpiece to be processed arranged on the top of the workbench via a positioning mechanism, a laser cladding mechanism mounted above the workpiece to be processed, and a focused ultrasonic vibration mechanism symmetrically arranged on both sides of the laser cladding mechanism via a multi-degree-of-freedom variable angle clamping mechanism, wherein the focused ultrasound emitted by the focused ultrasonic vibration mechanism is aligned with the cladding area of ​​the laser cladding mechanism.

[0015] Preferably, the ultrasonic vibration mechanism comprises an ultrasonic generator, an ultrasonic transducer, a focusing horn and a diffraction focusing acoustic lens which are arranged in sequence, the ultrasonic generator is electrically connected to the ultrasonic transducer, the transmitting end of the ultrasonic transducer is aligned with one end of the focusing horn, the other end of the focusing horn is arranged as a concave focusing head, the concave focusing head is arranged concentrically with the diffraction focusing acoustic lens, and the diffraction focusing acoustic lens is fixedly connected to the ultrasonic transducer via a connecting rod;

[0016] The diffraction focusing acoustic lens consists of transparent rings and non-transparent rings arranged concentrically alternately.

[0017] Preferably, the multi-degree-of-freedom variable angle clamping mechanism includes a three-dimensional displacement platform, an angle adjustment unit arranged at the output end of the three-dimensional displacement platform, and a clamping ring connected to the output end of the angle adjustment unit, and the clamping ring is clamped to the outer wall of the ultrasonic transducer.

[0018] Preferably, the three-axis displacement platform comprises an X-axis adjustment component, a Y-axis adjustment component and a Z-axis adjustment component connected in sequence, each of which comprises a base and a slide plate slidably arranged on the base, a rack is fixed on the side of the base facing the slide plate, a displacement adjustment gear meshing with the rack is rotatably arranged on the slide plate, the wheel axle of the displacement adjustment gear is connected to a displacement adjustment hand wheel rotatably arranged on the slide plate, and the slide plate is also positioned and connected to the base via a positioning bolt;

[0019] The base of the X-direction adjustment component is connected to the laser cladding mechanism via a connecting plate, and the slide plate of the Z-direction adjustment component is connected to the angle adjustment unit.

[0020] Preferably, the angle adjustment unit includes a pitch angle adjustment component and a horizontal angle adjustment component, the pitch angle adjustment component includes a pitch angle adjustment gear vertically rotatably arranged on a slide plate of the Z-direction adjustment component and a pitch angle adjustment hand wheel meshed with the pitch angle adjustment gear, the pitch angle adjustment hand wheel is rotatably arranged on an adjustment plate, a slider is fixed to one end of the adjustment plate facing the slide plate of the Z-direction adjustment component, the slider is slidably connected to an arc-shaped slide groove provided on the slide plate of the Z-direction adjustment component, and the arc-shaped slide groove is concentrically arranged with the pitch angle adjustment gear;

[0021] The horizontal angle adjustment assembly includes a horizontal angle adjustment hand wheel rotatably arranged on the adjustment plate, the horizontal angle adjustment hand wheel penetrates into the adjustment plate and is connected with a worm gear, the worm gear is meshed with one end of a worm rotatably arranged inside the adjustment plate, and the other end of the worm gear is fixedly connected with a clamping ring;

[0022] The adjusting plate and the slide plate of the Z-direction adjusting component as well as the worm and the adjusting plate are all positioned and connected via positioning top screws.

[0023] Preferably, the present invention also includes a cooling mechanism, which includes a cooling water tank and a circulating pump. The outlet pipe of the cooling water tank passes through the circulating pump and then through a heat exchange pipe to be bonded to the ultrasonic transducer and the laser cladding mechanism respectively. The heat exchange pipe is also connected to the circulating pump through a return water port.

[0024] Preferably, the heat exchange tube is also connected to a water cooling plate attached to the diffraction focusing acoustic lens via a water pipe, the water cooling plate is a multi-layer annular water cooling coil structure, two adjacent layers of annular water cooling coils are connected via a connecting pipe, and the annular water cooling coil is fixedly connected to the non-transparent ring surface of the diffraction focusing acoustic lens on one side of the cladding area;

[0025] The multiple layers of annular water cooling coils are all arranged concentrically with the diffraction focusing acoustic lens, and the inner diameter of the innermost annular water cooling coil is not less than the lowest diffraction radius of the diffraction focusing acoustic lens.

[0026] Preferably, the material of the transparent ring of the diffraction focusing acoustic lens is polyimide.

[0027] Preferably, the positioning mechanism comprises a positioning cylinder arranged around the workpiece to be processed, and a positioning plate is fixed to the position of the positioning cylinder facing the workpiece to be processed.

[0028] The working method of the multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device comprises the following steps:

[0029] S1. Loading: Place the workpiece to be processed on the workbench, start the positioning cylinder, and the positioning cylinder drives the positioning plate to clamp the edge of the workpiece to be processed;

[0030] S2. Position adjustment: turn the displacement adjustment gears on the X-axis adjustment component, the Y-axis adjustment component and the Z-axis adjustment component in sequence. The displacement adjustment gear drives the slide plate to slide along the base under the meshing action of the rack, adjusts the position of the ultrasonic transducer, makes the two ultrasonic transducers symmetrical about the laser cladding mechanism, and then uses the positioning bolt to locate the current position; then turn the pitch angle adjustment handwheel to drive the adjustment plate to rotate around the pitch angle adjustment gear, thereby adjusting the pitch angle of the ultrasonic transducer, and then turn the horizontal angle adjustment handwheel to drive the ultrasonic transducer to rotate under the action of the worm gear, to ensure that the ultrasound emitted by the ultrasonic transducer is amplified by the focusing amplitude rod and propagated to the center of the diffraction focusing acoustic lens, and uses the diffraction focusing acoustic lens to focus the ultrasound to the cladding area, and finally uses the positioning top screw to locate the current position;

[0031] S3, turning on the laser cladding mechanism, aiming the laser emitted by the laser cladding head of the laser cladding mechanism at the cladding area, and the powder feeder of the laser cladding mechanism feeds the powder to the cladding area, and the powder is melted under the combined action of the laser and ultrasonic assistance, and covers the cladding area of ​​the workpiece to be processed;

[0032] The circulation pump of the cooling mechanism and the laser cladding mechanism are turned on in sequence, and the ultrasonic transducer, the laser cladding mechanism and the diffraction focusing acoustic lens are cooled simultaneously with cooling water.

[0033] Therefore, the present invention adopts the above-mentioned multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device and its working method, which has the following beneficial effects:

[0034] 1. The multi-level focusing mechanism works together to achieve precise and high-intensity focusing of ultrasonic energy, significantly improving the energy density of the cladding area, which is conducive to obtaining better processing quality; at the same time, by reducing energy loss and ineffective radiation, the utilization efficiency of ultrasonic energy is improved, energy consumption is reduced, and processing efficiency is improved, so it can be widely used in laser cladding remanufacturing of various materials, especially in fields with high requirements for remanufacturing processing quality, such as aerospace, automobile manufacturing, precision machinery, etc.

[0035] 2. Ultrasonic vibration can be precisely focused on the molten pool. At the same time, the thermal effect, cavitation effect and acoustic streaming effect generated by the ultrasonic focus can promote the formation of crystal nuclei and the fluidity of liquid metal, making the organizational composition more uniform and the structure more compact, improving the strength and wear resistance of the remanufacturing cladding layer, thereby improving the quality and efficiency of laser cladding remanufacturing processing;

[0036] 3. The two ultrasonic vibration mechanisms are symmetrically arranged to achieve a wider ultrasonic energy coverage and more uniform ultrasonic action, while reducing energy attenuation, improving ultrasonic effect, avoiding the problem of energy attenuation encountered by a single ultrasonic vibration mechanism during transmission, and more effectively controlling the microstructure of the remanufactured cladding layer; multi-dimensional ultrasonic vibration can affect the growth direction and morphology of grains, thereby achieving finer microstructure control, and can produce stronger cavitation and acoustic streaming effects, while nonlinear effects play an important role in suppressing defects (such as cracks and pores) in the cladding layer. Stronger cavitation and acoustic streaming effects can more effectively stir the molten pool, promote gas discharge and uniform distribution of crystal nuclei, and through a more efficient defect suppression mechanism, reduce the number of defects in the remanufactured cladding layer, and improve the quality and reliability of the cladding layer;

[0037] 4. The two ultrasonic vibration mechanisms can back up each other, thereby reducing the impact of downtime on production;

[0038] 5. Enhanced adaptability: The multi-degree-of-freedom variable angle clamping mechanism can flexibly adjust the position and angle of the ultrasonic vibration mechanism in three-dimensional space, increasing the universality of the device;

[0039] 6. Improve processing efficiency: Through the assistance of high-intensity focused ultrasound, the stirring of the molten pool and the uniform distribution of materials are promoted, the heating efficiency and cladding speed are improved, thereby reducing the processing cost;

[0040] 7. Easy to optimize and expand: The diffraction focusing acoustic lens has a simple structure, is easy to optimize the design, and can adapt to sound waves of different frequencies to meet the needs of various application scenarios.

[0041] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the overall structure of a multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device of the present invention;

[0043] Figure 2 It is a front view of a multi-degree-of-freedom variable-angle clamping mechanism of a multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device of the present invention;

[0044] Figure 3 It is a structural schematic diagram of an ultrasonic vibration mechanism of a multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device of the present invention;

[0045] Figure 4 The invention discloses a diffraction focusing acoustic lens for a multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device.

[0046] Reference numerals

[0047] 1. Workbench; 2. Ultrasonic transducer; 3. Focusing horn; 31. Concave focusing head; 4. Diffraction focusing acoustic lens; 41. Transparent ring; 42. Non-transparent ring; 5. Laser cladding mechanism; 6. Y-axis adjustment component; 7. X-axis adjustment component; 8. Z-axis adjustment component; 9. Pitch angle adjustment component; 10. Horizontal angle adjustment component; 11. Positioning cylinder; 12. Workpiece to be processed; 13. Ultrasonic generator; 14. Rack; 15. Displacement adjustment gear; 16. Displacement adjustment hand wheel; 17. Pitch angle adjustment gear; 18. Pitch angle adjustment hand wheel; 19. Horizontal angle adjustment hand wheel; 20. Adjustment plate; 21. Worm; 22. Snap ring; 23. Water cooling plate. DETAILED DESCRIPTION

[0048] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the invented product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "setting", "installation", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0050] like Figure 1-Figure 4 As shown, a multi-degree-of-freedom ultrasound-assisted laser cladding remanufacturing device includes a workbench 1, a workpiece 12 to be processed which is arranged on the top of the workbench 1 via a positioning mechanism, a laser cladding mechanism 5 erected above the workpiece 12 to be processed, and a focused ultrasonic vibration mechanism symmetrically arranged on both sides of the laser cladding mechanism 5 via a multi-degree-of-freedom variable angle clamping mechanism, and the focused ultrasound emitted by the focused ultrasonic vibration mechanism is aligned with the cladding area of ​​the laser cladding mechanism 5.

[0051] Among them, the ultrasonic vibration mechanism includes an ultrasonic generator 13, an ultrasonic transducer 2, a focusing horn 3 and a diffraction focusing acoustic lens 4 which are arranged in sequence, the ultrasonic generator 13 is electrically connected to the ultrasonic transducer 2, the transmitting end of the ultrasonic transducer 2 is aligned with one end of the focusing horn 3, and the other end of the focusing horn 3 is configured as a concave focusing head 31 (the concave structure not only improves the focusing ability, but also reduces the reflection and loss of energy during the transmission process through impedance matching), the concave focusing head 31 is concentrically arranged with the diffraction focusing acoustic lens 4, and the diffraction focusing acoustic lens 4 is fixedly connected to the ultrasonic transducer 2 via a connecting rod; the diffraction focusing acoustic lens 4 is composed of transparent rings 41 and non-transparent rings 42 which are alternately arranged concentrically.

[0052] The working principle of the ultrasonic generator (also called ultrasonic power supply) is to convert electrical energy into mechanical energy through a certain energy conversion mechanism; the ultrasonic transducer is used to convert electromagnetic energy into mechanical energy (acoustic energy) and generate ultrasonic waves; the main function of the focusing amplitude rod 3 is to amplify the mechanical vibration amplitude generated by the ultrasonic transducer 2 and effectively transfer the vibration energy to the molten pool or other processing areas; the design of the diffraction focusing acoustic lens 4 is based on the principle of Fresnel zone plate and uses the ring-shaped structure to phase modulate the sound wave, so that the phase difference of the sound waves of each ring-shaped zone at the focus is zero, thereby achieving the focusing of the sound wave.

[0053] Compared with the traditional focusing acoustic lens, the diffraction focusing acoustic lens 4 has the following advantages:

[0054] 1. Simple structure: The design of the diffraction focusing acoustic lens 4 is based on the principle of Fresnel zone plates. Its structure is usually a series of concentric rings or annuli. Compared with traditional refractive or reflective acoustic lenses, its structure is simpler and the difficulty of processing and manufacturing is reduced. 2. Thinner axial thickness: Since the diffraction focusing acoustic lens 4 uses the diffraction principle to achieve focusing, and does not need to rely on the refractive index difference of the material like a refractive lens, its axial thickness can be thinner, which is conducive to miniaturization and integration. 3. Wide-band characteristics: The design of the diffraction focusing acoustic lens 4 can adapt to sound waves of different frequencies by adjusting the width and spacing of the annular belt, so it can maintain a good focusing effect in a wider frequency range, and has a wider range of application than traditional lenses. 4. Obvious sound pressure amplification effect: The diffraction focusing acoustic lens 4 can effectively focus the sound wave energy to a point or a small area to achieve significant amplification of the sound pressure. 5. Wide range of applicable frequencies: Since it is based on the diffraction principle, the diffraction focusing acoustic lens 4 is not limited by the refractive index of the material, so it can be applied to a wide frequency range from low frequency to high frequency to meet the needs of different application scenarios. 6. Low cost: Advanced manufacturing technology (such as 3D printing, etc.) can be used, and the diffraction focusing acoustic lens 4 can be mass-produced, thereby reducing manufacturing costs and facilitating promotion and application. 7. Reduced transmission loss: Compared with the traditional refractive acoustic lens, the diffraction focusing acoustic lens 4 has less absorption effect on the sound waves in the process of converging the sound waves, so it can reduce the transmission loss and improve the energy utilization rate. 8. Easy to optimize the design: The ring belt structure and size of the diffraction focusing acoustic lens 4 can be easily adjusted to achieve the best focusing effect and sound pressure amplification multiple.

[0055] The multi-degree-of-freedom variable angle clamping mechanism includes a three-dimensional displacement platform, an angle adjustment unit arranged at the output end of the three-dimensional displacement platform, and a clamping ring 22 connected to the output end of the angle adjustment unit, and the clamping ring 22 is clamped with the outer wall of the ultrasonic transducer 2. Among them, the three-dimensional displacement platform includes an X-axis adjustment component 7, a Y-axis adjustment component 6, and a Z-axis adjustment component 8 connected in sequence, and the X-axis adjustment component 7, the Y-axis adjustment component 6, and the Z-axis adjustment component 8 all include a base and a slide plate slidably arranged on the base, a rack 14 is fixed on the base and on one side facing the slide plate, and a displacement adjustment gear 15 meshing with the rack 14 is rotatably arranged on the slide plate, and the wheel axle of the displacement adjustment gear 15 is connected to a displacement adjustment hand wheel 16 rotatably arranged on the slide plate, and the slide plate is also positioned and connected to the base via a positioning bolt; the base of the X-axis adjustment component 7 is connected to the laser cladding mechanism 5 via a connecting plate, and the slide plate of the Z-axis adjustment component 8 is connected to the angle adjustment unit.

[0056] By setting up a three-dimensional displacement platform, the distance between the ultrasonic vibration mechanism and the molten pool can be adjusted to achieve effective coupling between the ultrasonic vibration and the molten pool, thereby making the application of ultrasound more uniform.

[0057] The angle adjustment unit includes a pitch angle adjustment component 9 and a horizontal angle adjustment component 10. The pitch angle adjustment component 9 includes a pitch angle adjustment gear 17 vertically rotatably arranged on a slide plate of the Z-direction adjustment component 8 and a pitch angle adjustment hand wheel 18 meshing with the pitch angle adjustment gear 17. The pitch angle adjustment hand wheel 18 is rotatably arranged on an adjustment plate 20. A slider is fixed to one end of the adjustment plate 20 facing the slide plate of the Z-direction adjustment component 8. The slider is slidably connected to an arc-shaped slide groove on the slide plate of the Z-direction adjustment component 8. The arc-shaped slide groove is arranged concentrically with the pitch angle adjustment gear 17; the horizontal angle adjustment assembly 10 includes a horizontal angle adjustment hand wheel 19 rotatably set on the adjustment plate 20, and the horizontal angle adjustment hand wheel 19 is connected with the worm gear after passing through the adjustment plate 20, and the worm gear is meshed with one end of a worm 21 rotatably set inside the adjustment plate 20, and the other end of the worm 21 is fixedly connected with a retaining ring 22; the adjustment plate 20 and the slide plate of the Z-direction adjustment assembly 8 as well as the worm 21 and the adjustment plate 20 are all positioned and connected by positioning top screws.

[0058] The present invention also includes a cooling mechanism, which includes a cooling water tank and a circulation pump. The water outlet pipe of the cooling water tank is respectively attached to the ultrasonic transducer 2 and the laser cladding mechanism 5 through the heat exchange pipe after passing through the circulation pump, and the heat exchange pipe is also connected to the circulation pump through the return water port. The heat exchange pipe is also connected to the water cooling plate 23 attached to the diffraction focusing acoustic lens 4 through a water pipe. The water cooling plate 23 is a multi-layer annular water cooling coil structure. The adjacent two layers of annular water cooling coils are connected through a connecting pipe, and the annular water cooling coil is fixedly connected to the side of the non-transparent ring 42 of the diffraction focusing acoustic lens 4 facing the cladding area; the multi-layer annular water cooling coils are all arranged concentrically with the diffraction focusing acoustic lens 4, and the inner diameter of the innermost annular water cooling coil is not less than the minimum diffraction radius of the diffraction focusing acoustic lens 4.

[0059] The material of the transparent ring 41 of the diffraction focusing acoustic lens 4 is polyimide.

[0060] The positioning mechanism includes a positioning cylinder 11 arranged around a workpiece 12 to be processed, and a positioning plate is fixed to the positioning cylinder 11 facing the workpiece 12 to be processed.

[0061] The working method of the multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device comprises the following steps:

[0062] S1, loading: placing the workpiece 12 to be processed on the workbench 1, starting the positioning cylinder 11, and the positioning cylinder 11 drives the positioning plate to clamp the edge of the workpiece 12 to be processed;

[0063] S2, position adjustment: turn the displacement adjustment gear 15 on the X-axis adjustment component 7, the Y-axis adjustment component 6 and the Z-axis adjustment component 8 in sequence, and the displacement adjustment gear 15 drives the slide plate to slide along the base under the meshing action of the rack 14, adjust the position of the ultrasonic transducer 2, so that the two ultrasonic transducers 2 are symmetrical about the laser cladding mechanism 5, and then use the positioning bolt to locate the current position; then turn the pitch angle adjustment hand wheel 18 to drive the adjustment plate 20 to rotate around the pitch angle adjustment gear 17, so as to adjust the pitch angle of the ultrasonic transducer 2, and then turn the horizontal angle adjustment hand wheel 19 to drive the ultrasonic transducer 2 to rotate under the action of the worm gear 21, to ensure that the ultrasound emitted by the ultrasonic transducer 2 is amplified by the focusing amplitude rod 3 and then propagated to the center of the diffraction focusing acoustic lens 4, and the diffraction focusing acoustic lens 4 is used to focus the ultrasound to the cladding area, and finally the current position is located using the positioning top screw;

[0064] S3, turning on the laser cladding mechanism 5, aiming the laser emitted by the laser cladding head of the laser cladding mechanism 5 at the cladding area, and the powder feeder of the laser cladding mechanism 5 feeds the powder to the cladding area, and the powder is melted under the combined action of the laser and ultrasonic assistance, and covers the cladding area of ​​the workpiece 12 to be processed;

[0065] The circulation pump of the cooling mechanism and the laser cladding mechanism are turned on in sequence, and the ultrasonic transducer 2, the laser cladding mechanism 5 and the diffraction focusing acoustic lens 4 are cooled simultaneously with cooling water. In this embodiment, the working temperature of each component can be collected in real time with the help of a temperature sensor, so as to adjust the cooling water outlet temperature and keep the working temperature stable.

[0066] In step S3, a robotic arm or other displacement mechanism may be used to drive the laser cladding mechanism 5 and the ultrasonic transducer 2 to move synchronously, thereby achieving specific path processing.

[0067] Test example

[0068] 1. Preparation before debugging

[0069] (1) Material preparation: Prepare a thin polydimethylsiloxane film (PDMS film) for testing the intensity of focused ultrasound; prepare an appropriate amount of metal powder for adjusting the focusing position and angle.

[0070] (2) Environmental settings: Ensure that the working environment is clean and tidy without other interference factors so as to accurately observe and record the debugging results; adjust the shooting angle and focal length of the infrared camera or thermal camera to accurately capture the temperature changes of the PDMS film.

[0071] 2. Debug the laser cladding mechanism and ultrasonic vibration mechanism

[0072] (3) Preliminary focusing: Using the infrared generator at the nozzle of the laser head of the laser cladding mechanism, adjust the infrared light emitted by the infrared generator to form a light spot on the substrate so that it is roughly aligned with the expected remanufacturing processing position.

[0073] (2) Install the ultrasonic transducer on the multi-degree-of-freedom variable angle clamping mechanism through a clamping ring, and preliminarily set its vibration frequency and power.

[0074] (3) Use the hand wheel to adjust the position and angle of the ultrasonic vibration mechanism so that the ultrasonic focal point is roughly located in the expected cladding area.

[0075] (4) Placing the PDMS film: Place the PDMS film flatly on the workbench and ensure that its position is stable.

[0076] (5) Start the equipment: Start the ultrasonic generator and set the initial ultrasonic intensity and frequency.

[0077] (6) Temperature monitoring: Use an infrared camera or a thermal camera to focus on the PDMS film and start recording its temperature changes.

[0078] (7) Parameter adjustment: According to the temperature change, the ultrasonic intensity and frequency are gradually adjusted. The goal is to raise the temperature of the PDMS film from room temperature to 80 degrees Celsius within 20 seconds. When this goal is achieved, the current ultrasonic intensity and frequency parameters are recorded as a reference for subsequent remanufacturing.

[0079] (8) Material replacement: Remove the PDMS film and evenly spread a layer of metal powder (1 mm thick) on the substrate, while maintaining the previously set ultrasonic intensity unchanged.

[0080] (9) Position adjustment: Start adjusting the position of the ultrasonic vibration mechanism (i.e., the distance between the diffraction focusing acoustic lens and the metal powder layer). By gradually reducing the distance, observe the changes in the metal powder layer under the action of ultrasound. When the powder layer begins to produce tiny depressions, it means that the focusing effect begins to appear.

[0081] (10) Angle adjustment: At the same time, adjust the angle of the ultrasonic vibration mechanism so that the ultrasonic focal point and the light spot coincide with each other to ensure that they can accurately act on the same area. By fine-tuning the angle, observe the changes in the depression of the powder layer to find the best focusing effect.

[0082] (11) Repeated debugging: Repeatedly adjust the position and angle to determine the focal point that causes the maximum depression in the metal powder layer, and record the position and angle parameters at this time.

[0083] 3. Laser cladding remanufacturing

[0084] (1) Surface treatment of remanufactured workpieces: Use appropriate cleaning agents or solvents to clean the surface of the workpiece to be processed to remove impurities such as oil, rust, etc., perform mechanical processing to remove the oxide layer on the surface to be remanufactured, and then perform sandblasting to roughen the surface to reduce the laser reflectivity, followed by cleaning and drying.

[0085] (2) Fix the workpiece: Fix the workpiece to ensure that it does not move or shake during the processing.

[0086] (3) Preset laser path and set processing parameters: Plan the area that needs to be remanufactured based on the dimensional parameters and performance requirements of the workpiece remanufacturing surface.

[0087] (4) Parameter setting: Set processing parameters, including laser power, cladding speed, powder feeding rate, etc.

[0088] (5) Start ultrasonic and laser cladding: The laser generator uses a fiber laser, and the laser cladding head is aligned with the starting point of the area to be clad (argon is used as the powder feeding gas and protective gas in the remanufacturing process to prevent oxidation).

[0089] (6) Start ultrasound: First start the ultrasonic vibration mechanism to ensure that it works normally and generates stable ultrasonic waves, and adjust the ultrasonic intensity and frequency parameters to the previously debugged parameters.

[0090] (7) Start the laser: Turn on the synchronous powder feeder and fiber laser through the console. The laser cladding head starts to scan along the preset path. The laser cladding head and the ultrasonic vibration mechanism move synchronously to ensure that the laser beam and the ultrasonic vibration focus are at the same position in the area to be clad. During the movement, the synchronous powder feeder delivers the powder to the laser coaxial powder feeding nozzle. The powder is ejected from the lower end of the laser coaxial powder feeding nozzle and melted by the laser irradiation, covering the cladding area. At the same time, the ultrasonic vibration mechanism continues to apply ultrasonic assistance to the molten pool.

[0091] At the same time, during the processing, pay close attention to the working status of the laser cladding head and the ultrasonic vibration mechanism to ensure that the two can move synchronously and accurately act on the same area.

[0092] Monitoring and adjustment during the remanufacturing process: When repairing and remanufacturing small-sized parts, they can work continuously; when remanufacturing large-sized parts, it is necessary to monitor the temperature of the focused ultrasonic vibration head and adopt an interlayer pause strategy (that is, pausing the processing process and continuing the processing after the temperature drops or the parameters are adjusted, which helps to ensure the processing quality and equipment safety) to ensure that the focused ultrasonic head is in a suitable temperature working range. And according to the actual situation during the processing, timely adjust the parameters such as laser power, cladding speed, powder feeding rate, etc. For example, when cracks or pores are found in the cladding layer, the cladding speed can be appropriately reduced, the powder feeding rate can be increased, and the frequency and amplitude of the ultrasonic vibration can be adjusted to improve the cladding quality.

[0093] 4. End of processing and subsequent treatment

[0094] (1) Turn off the equipment: After the remanufacturing process is completed, first turn off the ultrasonic vibration mechanism and laser cladding mechanism, and then turn off the cooling mechanism.

[0095] (2) Cooling treatment: Wait until the workpiece cools down to room temperature naturally before taking out the processed workpiece. Avoid taking out the workpiece directly at high temperature to prevent deformation or burns.

[0096] (3) Post-processing: Perform necessary post-processing (such as grinding, polishing, etc.) on the processed workpiece to remove surface defects and improve its performance.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device, characterized in that: It comprises a workbench, a workpiece to be processed which is arranged on the top of the workbench via a positioning mechanism, a laser cladding mechanism which is erected above the workpiece to be processed, and a focused ultrasonic vibration mechanism which is symmetrically arranged on both sides of the laser cladding mechanism via a multi-degree-of-freedom variable angle clamping mechanism, wherein the focused ultrasonic vibration mechanism emits a focused ultrasound which is aligned with a cladding area of ​​the laser cladding mechanism; The multi-degree-of-freedom variable angle clamping mechanism comprises a three-dimensional displacement platform, an angle adjustment unit arranged at the output end of the three-dimensional displacement platform, and a clamping ring connected to the output end of the angle adjustment unit, wherein the clamping ring is clamped with the outer wall of the ultrasonic transducer; The ultrasonic vibration mechanism includes an ultrasonic generator, an ultrasonic transducer, a focusing horn and a diffraction focusing acoustic lens which are arranged in sequence, the ultrasonic generator is electrically connected to the ultrasonic transducer, the transmitting end of the ultrasonic transducer is aligned with one end of the focusing horn, the other end of the focusing horn is arranged as a concave focusing head, the concave focusing head is arranged concentrically with the diffraction focusing acoustic lens, and the diffraction focusing acoustic lens is fixedly connected to the ultrasonic transducer via a connecting rod; The diffraction focusing acoustic lens is composed of transparent rings and non-transparent rings arranged concentrically in alternation; The material of the transparent ring of the diffraction focusing acoustic lens is polyimide.

2. A multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device according to claim 1, characterized in that: The three-axis displacement platform comprises an X-axis adjustment component, a Y-axis adjustment component and a Z-axis adjustment component which are connected in sequence, wherein the X-axis adjustment component, the Y-axis adjustment component and the Z-axis adjustment component each comprise a base and a slide plate which is slidably arranged on the base, a rack is fixed on the side of the base facing the slide plate, a displacement adjustment gear which meshes with the rack is rotatably arranged on the slide plate, a wheel axle of the displacement adjustment gear is connected to a displacement adjustment hand wheel which is rotatably arranged on the slide plate, and the slide plate is also positioned and connected to the base via a positioning bolt; The base of the X-direction adjustment component is connected to the laser cladding mechanism via a connecting plate, and the slide plate of the Z-direction adjustment component is connected to the angle adjustment unit.

3. A multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device according to claim 2, characterized in that: The angle adjustment unit includes a pitch angle adjustment component and a horizontal angle adjustment component. The pitch angle adjustment component includes a pitch angle adjustment gear vertically rotatably arranged on a slide plate of the Z-direction adjustment component and a pitch angle adjustment hand wheel meshed with the pitch angle adjustment gear. The pitch angle adjustment hand wheel is rotatably arranged on an adjustment plate. A slider is fixed to one end of the adjustment plate facing the slide plate of the Z-direction adjustment component. The slider is slidably connected to an arc-shaped slide groove provided on the slide plate of the Z-direction adjustment component. The arc-shaped slide groove is concentrically arranged with the pitch angle adjustment gear. The horizontal angle adjustment assembly includes a horizontal angle adjustment hand wheel rotatably arranged on the adjustment plate, the horizontal angle adjustment hand wheel penetrates into the adjustment plate and is connected with a worm gear, the worm gear is meshed with one end of a worm rotatably arranged inside the adjustment plate, and the other end of the worm gear is fixedly connected with a clamping ring; The adjusting plate and the slide plate of the Z-direction adjusting component as well as the worm and the adjusting plate are all positioned and connected via positioning top screws.

4. The multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device according to claim 3 is characterized in that: The multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device also includes a cooling mechanism, which includes a cooling water tank and a circulating pump. The outlet pipe of the cooling water tank passes through the circulating pump and then through the heat exchange pipe to be respectively bonded to the ultrasonic transducer and the laser cladding mechanism. The heat exchange pipe is also connected to the circulating pump through a return water port.

5. The multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device according to claim 4 is characterized in that: The heat exchange tube is also connected to a water cooling plate attached to the diffraction focusing acoustic lens through a water pipe. The water cooling plate is a multi-layer annular water cooling coil structure. Two adjacent layers of annular water cooling coils are connected through a connecting pipe, and the annular water cooling coil is fixedly connected to the non-transparent ring surface of the diffraction focusing acoustic lens facing the cladding area. The multiple layers of annular water cooling coils are all arranged concentrically with the diffraction focusing acoustic lens, and the inner diameter of the innermost annular water cooling coil is not less than the lowest diffraction radius of the diffraction focusing acoustic lens.

6. The multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device according to claim 5, characterized in that: The positioning mechanism comprises a positioning cylinder arranged around the workpiece to be processed, and a positioning plate is fixed to the position of the positioning cylinder facing the workpiece to be processed.

7. A working method of a multi-degree-of-freedom ultrasonic-assisted laser cladding remanufacturing device as described in claim 6, characterized in that: The following steps are involved: S1. Loading: Place the workpiece to be processed on the workbench, start the positioning cylinder, and the positioning cylinder drives the positioning plate to clamp the edge of the workpiece to be processed; S2. Position adjustment: turn the displacement adjustment gears on the X-axis adjustment component, the Y-axis adjustment component and the Z-axis adjustment component in sequence. The displacement adjustment gear drives the slide plate to slide along the base under the meshing action of the rack, adjusts the position of the ultrasonic transducer, and makes the two ultrasonic transducers symmetrical about the laser cladding mechanism, and then uses the positioning bolt to locate the current position; then turn the pitch angle adjustment handwheel to drive the adjustment plate to rotate around the pitch angle adjustment gear, thereby adjusting the pitch angle of the ultrasonic transducer, and then turn the horizontal angle adjustment handwheel to drive the ultrasonic transducer to rotate under the action of the worm gear, to ensure that the ultrasound emitted by the ultrasonic transducer is amplified by the focusing amplitude rod and propagated to the center of the diffraction focusing acoustic lens, and the diffraction focusing acoustic lens is used to focus the ultrasound to the cladding area, and finally the positioning screw is used to locate the current position; S3, turning on the laser cladding mechanism, aiming the laser emitted by the laser cladding head of the laser cladding mechanism at the cladding area, and the powder feeder of the laser cladding mechanism feeds the powder to the cladding area, and the powder is melted under the combined action of the laser and ultrasonic assistance, and covers the cladding area of ​​the workpiece to be processed; The circulation pump of the cooling mechanism and the laser cladding mechanism are turned on in sequence, and the ultrasonic transducer, the laser cladding mechanism and the diffraction focusing acoustic lens are cooled simultaneously with cooling water.

Images