Patent ID: 12241174

REFERENCE NUMERALS IN THE DRAWINGS

1. computer;2. pulsed laser;3. peristaltic pump;4. workpiece work arm;5. reflector;6. focusing lens;7. laser beam;8. tool anode;9. working tank;10. direct-current pulse power supply;11. thin-walled tubular workpiece;12. motion controller;13. tool anode work arm;14. x-y-z three-axis motion platform;15. plane localized coating;16. electric field line;17. annular localized coating;18. region to be plated;19. electrodeposition solution;20. thin-walled flat-plate workpiece;21. second tool anode;22. thin-walled box-shaped workpiece.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present disclosure are described in detail below and are exemplified in the accompanying drawings, where the same or similar reference signs indicate the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present disclosure, instead of limiting the present disclosure.

In the description of the present disclosure, it should be understood that terms such as “central”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “upper”, “lower”, “axial”. “radial”, “vertical”, “horizontal”, “inner”, and “outer” indicate directional or positional relationships based on the accompanying drawings. They are merely used for the convenience and simplicity of the description of the present disclosure, instead of indicating or implying that the demonstrated device or element is located in a specific direction or is constructed and operated in a specific direction. Therefore, they cannot be construed as limitations to the present disclosure. In the present disclosure, unless otherwise expressly specified and defined, terms such as “mounted”, “interconnected”, “connected”, and “fixed” should be understood in a broad sense. For example, they may be fixed connections, detachable connections, or integral connections; may be mechanical connections or electrical connections; may be direct connections or indirect connections through an intermediate medium; and may be internal communications between two elements. The specific meanings of the above terms in the present disclosure can be understood by persons of ordinary skill in the art according to specific situations.

A method for repairing an inner wall of a material through localized electrodeposition by using a hybrid laser-electrochemical technology is provided. A laser beam7emitted by a laser is focused and irradiated on a surface of a workpiece to be repaired, heat generated by the laser is transferred via thermal conduction to an inner surface of the workpiece to be repaired, and localized electrodeposition in a corresponding region on the back side of the workpiece to be repaired is induced by the regional thermal effect of the laser. Positive and negative electrodes of a direct-current pulse power supply10are connected to a tool anode8and the workpiece to be repaired, respectively. The tool anode8is arranged in the center of the workpiece to be repaired and is spaced from the workpiece to be repaired. The workpiece to be repaired is a conductor with good thermal conductivity, for example, a metallic material. The spatial and temporal distribution of laser energy and electrochemical parameters are adjusted to implement electrodeposition on the inner surface of the workpiece to be repaired, and the electrodeposition rate is controllable. The tool anode8with a helical structure is clamped by a tool anode work arm13and coaxially arranged with the hollow workpiece to be repaired. A motion control system is used to adjust the rotation speed and control the flow of an electrodeposition solution19. The tool anode8with the helical structure enables circulation of the electrodeposition solution19and quick replenishment of metal ions, hydrogen bubbles generated by the electrodeposition reaction are discharged in time, negative thermal impacts outside the laser irradiated region are significantly eliminated, the concentration and localization of the thermal effect of laser irradiation are optimized, and the precision and deposition rate of the coating are improved. The laser beam is focused on the outer surface of the workpiece to realize localized repairing of the inner wall, which avoids influences on the machining due to the blocking by the tool anode8and the direct laser ablation of the coating, realizes localized electrodeposition on inner surfaces of workpieces such as tubes and shafts that have inner walls difficult to machine, and greatly saves the plating solution.

The Specific Steps are as Follows:

A motion path model is drawn according to graphics of a region to be repaired. The model is optimized and then imported into a computer1.

The inner and outer surfaces of the workpiece to be repaired are pretreated.

The workpiece to be repaired is clamped by a workpiece work arm4and then fixed above a working tank9. The tool anode8is connected to the positive electrode of the direct-current pulse power supply10and is clamped by the tool anode work arm13to be placed in the center of the workpiece to be repaired. The tool anode8is coaxially arranged with the workpiece to be repaired and is spaced from the workpiece to be repaired. The workpiece to be repaired is connected to the negative electrode of the direct-current pulse power supply10.

The deposition solution19is injected into the working tank9. A liquid inlet and a liquid outlet of a peristaltic pump3are connected to the working tank9and an end of the workpiece to be repaired, respectively. The peristaltic pump3is turned on and the flow is adjusted to make the inner surface of the workpiece to be repaired and the tool anode8immersed in the deposition solution19. After being powered on, the workpiece to be repaired and the tool anode8form an electrochemical circuit. A uniform concentration of the deposition solution19is ensured during the electrochemical reaction.

The workpiece work arm4and the tool anode work arm13are mounted on an x-y-z three-axis motion platform14and their heights and positions are adjusted, so that the laser beam7is focused on the outer surface of the workpiece to be repaired and corresponds to the region to be repaired on the inner surface of the workpiece to be repaired.

The direct-current pulse power supply10and the pulsed laser2are turned on to achieve the effect of laser-induced electrochemical deposition.

A motion controller12controls rotation of the workpiece work arm4and coordinated motion of the x-y-z three-axis motion platform14to perform three-dimensional rapid machining on the workpiece according to a set motion path.

A device for repairing an inner wall of a material through localized electrodeposition by using a hybrid laser-electrochemical technology is provided, which includes a laser irradiation system, an electrodeposition machining system, a motion control system, and a circulation system of the electrodeposition solution19. The laser irradiation system includes the pulsed laser2, a reflector5, and a focusing lens6. The laser beam7emitted by the laser2is reflected at 45° by the reflector5and is redirected to be focused by the focusing lens6onto the surface of the workpiece to be repaired. The electrodeposition machining system includes the direct-current pulse power supply10, the working tank9, the workpiece to be repaired, and the tool anode8. The workpiece to be repaired is connected to the negative electrode of the direct-current pulse power supply10and is clamped by the workpiece work arm4to be placed above the working tank9. The tool anode8is connected to the positive electrode of the direct-current pulse power supply10and is clamped by the tool anode work arm13to be placed directly below the workpiece to be repaired, where the tool anode8is spaced from the workpiece to be repaired. The motion control system includes the computer and the motion controller. The computer controls the pulsed laser2, the peristaltic pump3, and the direct-current pulse power supply10. The motion controller controls the x-y-z three-axis motion platform14, the workpiece work arm4, and the tool anode work arm13. The circulation system of the electrodeposition solution19includes the tool anode8, the peristaltic pump3, and a pump tube. The peristaltic pump3provides a sufficient inlet flow of the electrodeposition solution19to make the electrodeposition solution19fully contact the cathode and the anode to form a circuit. The workpiece is clamped by the work arm4to perform axial rotation, so that rotary machining on the rotatable workpiece to be repaired can be implemented.

Referring toFIG.1, the computer1is connected to the direct-current pulse power supply10, the pulsed laser2, the peristaltic pump3, and the motion controller12. The computer1controls and adjusts laser parameters of the pulsed laser2, electrical parameters of the direct-current pulse power supply10, and flow parameters of the peristaltic pump3. The motion controller12controls the motion of the x-y-z three-axis motion platform14and the rotation of the workpiece work arm4and the tool anode work arm13that clamp the workpiece to be repaired and the tool anode8, respectively.

The workpiece to be repaired is placed above the working tank9. The tool anode8is located in the center of the workpiece to be repaired and is spaced from the inner wall of the workpiece to be repaired. The flow parameters of the peristaltic pump3are adjusted to make the space filled with the electrodeposition solution19. The positive electrode of the direct-current pulse power supply10is connected to the tool anode8and the negative electrode of the direct-current pulse power supply10is connected to the workpiece to be repaired to form an electrochemical circuit. The laser beam7emitted by the pulsed laser2is redirected by the reflector5and then focused by the focusing lens6onto the surface of the workpiece to be repaired. The thermal effect of the laser on the surface is transferred to the inner wall of the workpiece to be repaired to induce electrodeposition on the inner wall of the workpiece to be repaired. The motion controller12controls the rotation of the workpiece work arm4and the laser scanning path adjusted by the computer to implement deposition in the shape of the region to be repaired. The liquid inlet and the liquid outlet of the peristaltic pump3are connected to the working tank9and one end of the workpiece to be repaired, respectively. The electrodeposition solution19is stored in the working tank9. The peristaltic pump3provides power to deliver the deposition solution19from the working tank9into the workpiece to be repaired, and the electrodeposition solution19flows back into the working tank9via the other end of the workpiece to be repaired to form circulation.

Referring toFIG.2andFIG.3, the thermal effect generated after the laser beam is focused on the surface of the workpiece to be repaired is transferred to the inner wall of the workpiece to be repaired to cause a regional electric field concentration effect, thereby restricting electrodeposition to the back side of the laser irradiated region. When the focused laser beam7cyclically scans back and forth along the preset path, the repairing of a plane coating is realized on the inner wall of the workpiece to be repaired. The laser parameters, the electrical parameters, and the rotation speed of the tool anode8are adjusted and controlled for control over the thickness, precision, and deposition rate of the coating. After the workpiece to be repaired is adjusted and controlled to rotate by the motion controller12, the computer1adjusts different laser parameters and light output frequencies to prepare annular repaired coatings of different shapes and sizes.FIG.4is a process sectional view of the coating after localized repairing. Localized electroplating of the region to be repaired18is implemented via mutual cooperation of the rotation of the workpiece to be repaired and the scanning path of the laser beam7.

The Specific Implementation of the Present Disclosure is as Follows:

The shape of the region to be repaired is analyzed to design the laser scanning path and the dynamic adjustment and control scheme of the x-y-z three-axis motion platform14, to ensure that the repaired coating has the same flatness as the original coating and the dimensional precision of the coating meets the requirements.

The workpiece to be repaired needs to be made of a material with good thermal conductivity and has a thickness of 0 to 3 mm. The space between the inner wall of the workpiece and the tool anode8is kept in a range of 3 mm to 5 mm. The inner and outer surfaces of the workpiece to be repaired are pretreated. The workpiece to be repaired is connected to the negative electrode of the direct-current pulse power supply10, and the tool anode8is connected to the positive electrode of the direct-current pulse power supply10.

The material of the tool anode8is reasonably selected according to requirements of the coating and the deposition solution, and the shape of the tool anode8is customized according to the shape of the workpiece. The end of the tool anode8clamped by the tool anode work arm13needs to be insulated to ensure that the electric field only exists uniformly in the space between the tool anode8and the workpiece to be repaired.

The electrodeposition solution19is added into the working tank9. The tool anode8with the helical surface structure is clamped by the tool anode work arm13and rotates to enable rapid flowing of the electrodeposition solution. Therefore, the negative thermal impacts outside the laser irradiated region are significantly eliminated, the concentration of the thermal effect of laser irradiation is optimized, the localization of the coating is improved, and stray deposition is avoided.

The peristaltic pump3is turned on to enable circulation of the deposition solution, so that the metal ions are quickly replenished, the influence of concentration polarization is suppressed, the hydrogen bubbles generated by the electrodeposition reaction are discharged in time, and the surface quality and production efficiency of the coating are improved.

The laser2, the direct-current pulse power supply10, and the motion controller12are turned on and the x-y-z three-axis motion platform14is dynamically adjusted according to the shape and size of the region to be repaired, so that the size of the laser spot and the defocusing amount of the laser are adjusted to achieve efficient deposition in the region to be repaired.

Embodiment 1

A round tube made of a nickel sheet is taken as an example below to illustrate the implementation of a method for induced localized electrodeposition on a back side of a thin-walled workpiece through laser irradiation according to the present disclosure. The method includes the following steps:(1) The cathode used in this embodiment is a copper-based nickel-plated round tube with an outer diameter of 130 mm, a wall thickness of 0.1 mm, and a length of 30 mm. The tool anode is an insoluble anode made of a ruthenium-iridium coated titanium plate (15×20×2 mm) and is arranged inside the cathode. The cathode and the anode are spaced apart by 10 mm. The tube is filled with the electrodeposition solution. The current density is 2 A/m2, a unidirectional pulse power supply is adopted, the pulse frequency is 1 kHz, and the duty cycle is 50%, the laser single-pulse energy is 6 μJ, the scanning speed is 2000 mm/s, the laser pulse frequency is 4000 kHz, the scanning pitch is 0.02 mm, and the laser scanning time is 60 s, the ambient temperature is 25° C., and the deposited pattern is a linear coating.(2) Referring toFIGS.5A-5BandFIGS.6A-6B, the tube is cut open and the morphology of the coating on its inner surface is observed. The coating is 1 mm wide and about 3 μm thick. It can be seen that the coating has a clear shape, high brightness and flatness, and good appearance. Localized electrodeposition on the inner surface of the tube can be realized.

According to the method for induced localized electrodeposition on the back side of the thin-walled workpiece through laser irradiation, the laser beam7emitted by the laser is focused and irradiated on a front side of a thin-walled tubular workpiece11, heat generated by the laser is rapidly transferred via thermal conduction to a back side of the workpiece to induce electrodeposition, and the temperature rise in other regions on the back side is insufficient to cause electrochemical deposition; therefore, localized electrodeposition on the back side of the thin-walled tubular workpiece11is realized. The positive and negative electrodes of the direct-current pulse power supply10are connected to the tool anode8and the thin-walled tubular workpiece11, respectively. The thin-walled tubular workpiece11is a metal thin-walled workpiece with good thermal conductivity. The laser beam is focused on the front side of the workpiece to realize localized electrodeposition on the back side of the workpiece. This method is applicable to localized deposition on the back sides of thin-walled parts such as plates, tubes, and boxes.

Referring toFIG.7toFIG.9, the thermal effect generated after the laser beam is focused on the outer surface of the thin-walled tubular workpiece11is transferred to the inner wall of the thin-walled tubular workpiece11to cause a regional electric field concentration effect, thereby restricting electrodeposition to the back side of the laser irradiated region. When the focused laser beam7cyclically scans back and forth along the preset path, localized deposition of a plane coating is realized on the inner wall of the thin-walled tubular workpiece11. The laser parameters, the electrical parameters, and the rotation speed of a helical tool anode21are adjusted and controlled for control over the thickness, precision, and deposition rate of the coating. After the thin-walled tubular workpiece11is adjusted and controlled to rotate by the motion controller12, the computer1adjusts different laser parameters and light output frequencies to prepare annular localized coatings of different shapes and sizes.FIGS.5A-5Bare a process sectional view of the localized electrodeposited coating. Localized electroplating in the region to be deposited18is implemented via mutual cooperation of the rotation of the thin-walled tubular workpiece11and the scanning path of the laser beam7.

A thin-walled box-shaped workpiece22is placed in the working tank9. The tool anode8is located in the thin-walled box-shaped workpiece22and does not contact the thin-walled box-shaped workpiece22. The flow parameters of the peristaltic pump3are adjusted to make the thin-walled box-shaped workpiece22filled with the electrodeposition solution19. The positive electrode of the direct-current pulse power supply10is connected to the tool anode8and the negative electrode of the direct-current pulse power supply10is connected to the thin-walled box-shaped workpiece22to form an electrochemical circuit. The laser beam7emitted by the pulsed laser2is redirected by the reflector5and then focused by the focusing lens6onto the surface of the thin-walled box-shaped workpiece22. The thermal effect of the laser on the surface is transferred to the inner wall of the thin-walled box-shaped workpiece22to induced electrodeposition on the inner wall of the thin-walled box-shaped workpiece22. The motion controller12controls the position of the thin-walled box-shaped workpiece22and the laser scanning path adjusted by the computer to implement deposition in the shape of the target region. The liquid inlet and the liquid outlet of the peristaltic pump3are connected to the bottom of the thin-walled box-shaped workpiece22and the top of the working tank9, respectively. The electrodeposition solution19is stored in the working tank9. The peristaltic pump3provides power to deliver the deposition solution19from the bottom of the thin-walled box-shaped workpiece22to the top of the working tank9.

Embodiment 2

A nickel sheet is taken as an example below, that is, a thin-walled flat-plate workpiece20made of a nickel sheet is used to illustrate the implementation of the method for induced localized electrodeposition on the back side of the thin-walled workpiece through laser irradiation according to the present disclosure. The method includes the following steps:(1) The cathode and anode parameters, laser parameters, electrical parameters, and solution proportioning are determined. The cathode used in this embodiment is a copper-based nickel-plated plate (30×20×0.1 mm), the tool anode is an insoluble anode made of a ruthenium-iridium coated titanium mesh (15×20×2 mm), and the cathode and the anode are spaced apart by 3 mm. The current density is 2 A/m2, a unidirectional pulse power supply is adopted, the pulse frequency is 1 kHz, and the duty cycle is 50%, the laser single-pulse energy is 6 μJ, the scanning speed is 2000 mm/s, the laser pulse frequency is 2500 kHz, and the scanning pitch is 0.02 mm. The adopted electrodeposition system is an acid cyanide gold plating system, the solution is mainly composed of 6 g/L of potassium auric cyanide, 70 g/L of citric acid, 90 g/L of potassium citrate, and 3 g/L of cobalt sulfate heptahydrate, the pH value of the solution is 3.9 to 4.0, and the ambient temperature is 25° C.(2) The laser scanning path shown inFIG.10is drawn by the computer1. After the laser beam7is focused on the front side of the thin-walled flat-plate workpiece20and scans for 30 s according to the scanning motion path inFIG.10, a localized coating shown inFIGS.11A-11Dare obtained. It can be clearly seen from the figure that a localized coating completely consistent with the scanning path is obtained in the laser irradiated region on the front side of the workpiece. Due to the law of thermal conduction, the backside deposited region is slightly different from the scanning path, but the shape of the deposited region is still clear and complete, and the interface between the coating and the substrate is clear. This embodiment shows that the present disclosure can realize high-precision backside and double-sided localized deposition, and the process effects and expected results mentioned in the specification can be completely realized.(3) In order to verify whether the service performance of the coating prepared in this embodiment meets the requirements, the corrosion resistance, bonding force, soldering performance, and microhardness of the coating are tested and compared with the performance of gold-plated samples provided by professional electroplating companies, and the test results show that the prepared coating completely meets the actual production requirements.

Corrosion resistance test: The coating is immersed in 2 mol/L hydrochloric acid for 24 h, and the morphology changes of the coating are observed with an optical microscope and an electron microscope. If there is no obvious change in the coating and no evidence of corrosion such as cracking and stripping is found on the surface, it indicates that the gold-plated layer has good corrosion resistance. In addition, Tafel test is carried out on the coating in a 3.5% NaCl solution, and the test results show that the corrosion current density and the corrosion potential are equal to or superior to those of the coating prepared by a conventional gold plating process.

Bonding force test: A bending test and a thermal shock test are performed to check the bonding force of the gold-plated layer. In the bending test, the sample is repeatedly bent by 180° until it breaks and it is observed whether the coating falls off at the break. In the thermal shock test, the plated workpiece is placed in a resistance furnace at 280° C. for 30 min and then immediately quenched in water at the room temperature to observe the morphology of the coating. If stripping of the coating at the break is not found in the bending test and phenomena such as peeling, bulging, and stripping of the coating are not found in the thermal shock test, it indicates that the gold-plated layer in this application has good bonding force and can overcome extreme service conditions.

Soldering performance test: A constant-temperature electric soldering iron is used to perform a spot soldering test on the surface of the substrate and the gold-plated layer to observe and compare their wettability. The gold-plated layer prepared in this application has good surface wettability and the solder joints can be evenly spread, which ensures the soldering performance of the parts and guarantees the electronic stability of the electronic components.

Microhardness test: The microhardness of the gold-plated layer prepared with the optimized parameters is measured by a microhardness tester at a load of 10 g for 20 s. Five gold-plated samples are prepared with the optimized parameters, and five points are selected from each sample for microhardness testing and an average value is recorded. It can be seen from the microhardness test values that the average microhardness of the coating is 130 HV to 195 HV, which meets the microhardness requirements of the gold-plated layer and is applicable to the service conditions of repeated plugging and unplugging of the electronic components.

Embodiment 3

A round tube made of a nickel sheet is taken as an example below to illustrate the implementation of the method for induced localized electrodeposition on the back side of the thin-walled workpiece through laser irradiation according to the present disclosure. The method includes the following steps:(1) The cathode used in this embodiment is a copper-based nickel-plated round tube as shown inFIGS.5A-5B. The cathode has an outer diameter of 130 mm, a wall thickness of 0.1 mm, and a length of 30 mm. The tool anode is an insoluble anode made of a ruthenium-iridium coated titanium plate (15×20×2 mm) and is arranged inside the cathode. The cathode and the anode are spaced apart by 10 mm. The tube is filled with the electrodeposition solution. The current density is 2 A/m2, a unidirectional pulse power supply is adopted, the pulse frequency is 1 kHz, and the duty cycle is 50%, the laser pulse frequency is 4000 kHz, the scanning pitch is 0.02 mm, and the laser single-pulse energy is 3.6 μJ, the ambient temperature is 25° C., and the deposited pattern is a circle with a diameter of 3 mm.FIGS.6A-6Bshow comparison between the morphologies of the coatings obtained at different scanning speeds.(2)FIGS.13A-13Care images at the scanning speeds of 10 mm/s, 20 mm/s, and 30 mm/s, respectively. It can be observed that electrodeposition on the inner wall surface of the tube can be induced at different scanning speeds. The coating obtained at the scanning speed of 30 mm/s has a clear shape, high brightness and flatness, and good appearance.

Embodiment 4

A nickel sheet is taken as an example below to illustrate the implementation of the method for induced localized electrodeposition on the back side of the thin-walled workpiece through laser irradiation according to the present disclosure. The method includes the following steps:(1) The cathode used in this embodiment is a copper-based nickel-plated sheet (30×20×0.1 mm), the tool anode is an insoluble anode made of a ruthenium-iridium coated titanium plate (15×20×2 mm), and the cathode and the anode are spaced apart by 3 mm. The cathode and the anode are placed in parallel and facing each other. A unidirectional pulse power supply is adopted, the pulse frequency is 1 kHz, and the duty cycle is 50%, the laser pulse frequency is 3000 kHz, the ambient temperature is 25° C., and the deposited patterns are a 3×3 mm square and a circle with a diameter of 3 mm.FIGS.14A-14D,FIGS.15A-15F,FIGS.16A-16F, andFIGS.17A-17Fshow comparison between the morphologies of the coatings obtained with different laser single-pulse energy, scanning speeds, scanning pitches, and current densities, respectively.(2) As shown inFIGS.14A-14D, when the scanning speed is 10 mm/s, the scanning pitch is 0.02 mm, and the current density is 2 A/m2, the laser single-pulse energy forFIG.14AandFIG.14Cis 2.93 μJ and the laser single-pulse energy forFIG.14BandFIG.14Dis 4.8 μJ. It can be observed that localized electrodeposition on the back side of the metal thin-walled workpiece can be induced by different single-pulse energy. The coating obtained with the single-pulse energy of 4.8 μJ has a clear shape, high brightness and flatness, and good appearance.(3) As shown inFIGS.15A-15F, when the single-pulse energy is 4.8 μJ, the scanning pitch is 0.02 mm, and the current density is 2 A/m2, comparison is made between the coatings obtained at the scanning speeds of 5 mm/s inFIG.15AandFIG.15D, 10 mm/s inFIG.15BandFIG.15E, and 25 mm/s inFIG.15CandFIG.15F. It can be observed that localized electrodeposition on the back side of the metal thin-walled workpiece can be induced by different scanning speeds. The coating obtained at the scanning speed of 10 mm/s has a clear shape, high brightness and flatness, and good appearance.(4) As shown inFIGS.16A-16F, when the single-pulse energy is 4.8 μJ, the scanning speed is 10 mm/s, and the current density is 2 A/m2, comparison is made between the coatings obtained with the scanning pitches of 0.02 mm inFIG.16AandFIG.16D, 0.03 mm inFIG.16BandFIG.16E, and 0.05 mm inFIG.16CandFIG.16F. It can be observed that localized electroplating on the back side of the metal thin-walled workpiece can be induced by different scanning pitch parameters. The coating obtained with the scanning pitch of 0.02 mm has a clear shape, high brightness and flatness, and good appearance.(5) As shown inFIGS.17A-17F, when the single-pulse energy is 4.8 μJ, the scanning speed is 10 mm/s, and the scanning pitch is 0.02 mm, comparison is made between the coatings obtained with the current densities of 1 A/m2inFIG.17AandFIG.17D, 2 A/m2inFIG.17BandFIG.17E, and 3 A/m2inFIG.17CandFIG.17F. It can be observed that localized electroplating on the back side of the thin-walled workpiece can be induced by different current densities. The coating obtained with the current density of 2 A/m2has a clear shape, high brightness and flatness, and good appearance.

According to Embodiments 1 to 4, good localized repairing can be achieved with the thickness of the thin-walled tubular workpiece and the sheet in 0 to 3 mm, the laser single-pulse energy of 0.1 μJ to 30 μJ, the scanning speed of 10 mm/s to 2000 mm/s, the laser scanning frequency of 500 kHz to 4000 kHz, the laser scanning pitch of 10 μm to 100 μm, and the laser scanning time of 5 s to 300 s, the voltage of 1 V to 5 V, the current pulse frequency of 1 kHz to 1000 kHz, and the current density of 0.1 A/m2to 5 A/m2.

In this specification, descriptions with reference to the terms “one embodiment”, “some embodiments”, “examples”, “specific examples”, “some examples” and the like denote that the specific features, structures, materials, or characteristics illustrated by the embodiments or examples are incorporated in at least one embodiment or example of the present disclosure. In this specification, the schematic statements of the above terms do not necessarily mean the same embodiments or examples. Moreover, the illustrated specific features, structures, materials, or characteristics can be properly combined in any one or more embodiments or examples.

Although the embodiments of the present disclosure have been shown and described, it can be understood that the above embodiments are exemplary and shall not be construed as limitations to the present disclosure. Changes, modifications, replacements, and variations can be made to these embodiments within the scope of the present disclosure by persons of ordinary skill in the art without departing from the principle and purpose of the present disclosure.