A laser polishing apparatus incorporating gas protection and substrate heat dissipation and a method of use

Abstract

The application provides a laser polishing device combining gas protection and substrate heat dissipation and a use method; the device comprises a focusing mirror (1), a laser beam (2), a sample to be polished (3), a gas nozzle (4), a gas pipe (5), a high-pressure gas cylinder (6), a dust collector (7), a cooling liquid liquid level (8), a metal substrate (9), a stage (10), a water tank (11), a laser (12); the application also relates to a use method of the aforementioned device. The application forms a micro-nano rough structure on the surface of the metal substrate by chemical etching, electrochemical etching or laser etching and the like, introduces a hydrophilic oxide layer by oxidation treatment or plasma treatment, and further enhances the super-hydrophilic performance. The device has excellent liquid cooling capacity, gas protection performance and oxidation resistance, can efficiently conduct and dissipate heat during the laser polishing process, ensures the uniformity of the sample surface temperature, and prevents overheating and oxidation.

Description

Technical Field

[0001] This invention relates to the field of advanced manufacturing technology for aero-engines; and more particularly to a laser polishing apparatus and method of use that combines gas protection and substrate heat dissipation. Background Technology

[0002] Laser polishing is an advanced surface finishing technology that uses a high-energy laser beam to locally melt and rapidly solidify the surface of a material, thereby achieving a smooth surface. Compared to traditional mechanical and chemical polishing, laser polishing offers significant advantages such as non-contact processing, high precision, and high efficiency. It is particularly suitable for processing difficult-to-handle high-performance materials, such as nickel-based alloys, titanium alloys, and ceramic matrix composites. With the continuous advancement of aerospace technology, laser polishing plays an increasingly important role in improving the surface quality of key components and extending their service life, and has become an indispensable process in this field.

[0003] Taking IN718 nickel-based alloy as an example, this is a precipitation-hardening nickel-chromium-based superalloy. Due to its excellent high-temperature strength, creep resistance, corrosion resistance, and good machinability, it is widely used in the manufacture of key components such as turbine blades, turbine disks, and rocket nozzles for aero-engines. However, these materials typically possess high strength and high hardness, making them typical difficult-to-machine materials. Traditional polishing methods are prone to surface oxidation, thermal damage, and microcracks during processing. Laser polishing technology overcomes these technical challenges due to its unique processing principle, but its heat dissipation and surface protection under high-temperature processing environments still require further optimization. Summary of the Invention

[0004] The purpose of this invention is to provide a laser polishing apparatus and method of use that combines gas protection and substrate heat dissipation.

[0005] This invention is achieved through the following technical solution:

[0006] The present invention relates to a laser polishing device that combines gas protection and substrate heat dissipation, comprising: a focusing lens 1, a laser beam 2, a sample to be polished 3, a gas nozzle 4, a gas pipe 5, a high-pressure gas cylinder 6, a vacuum cleaner 7, a coolant surface 8, a metal substrate 9, a stage 10, a water tank 11, and a laser 12.

[0007] The surface of the metal substrate 9 is provided with a cooling liquid film consisting of a micro-nano structure and a hydrophilic oxide layer.

[0008] The stage 10 is placed inside the water tank 11, and the metal substrate 9 is placed at the upper end of the stage 10.

[0009] The sample 3 to be polished is placed on the metal substrate 9; the gas nozzle 4 and the vacuum cleaner 7 are respectively set at both ends of the sample 3 to be polished; the focusing lens 1 is suspended above the sample 3 to be polished.

[0010] The nozzle diameter of gas nozzle 4 is 5-10 mm, and the gas flow rate is controlled at 15-30 L / min.

[0011] The present invention also relates to a method of using the aforementioned laser polishing apparatus combining gas protection and substrate heat dissipation, comprising the following steps:

[0012] Step 1: The untreated metal substrate is subjected to ultrasonic cleaning to remove surface dirt and oil stains, dried, laser etched or etched with etching solution, rinsed with deionized water to remove surface debris and impurities, and then placed in an oxidation solution for oxidation treatment.

[0013] Step 2: Place the metal substrate 9 on the stage 10 and add coolant until a thin coolant film is formed on the surface of the metal substrate 9.

[0014] Step 3: Clean the surface of the sample 3 to be polished by ultrasonic cleaning to remove dirt and oil stains, and then dry it.

[0015] Step 4: Place the sample 3 to be polished after ultrasonic cleaning and drying pretreatment in the middle of the metal substrate 9 in the water tank 11 (the side of the sample to be polished is aligned with the laser head, and the other side is partially immersed in the coolant on the metal substrate). Due to the presence of the coolant film on the surface of the metal substrate 9, the bottom of the sample can be partially immersed in the coolant. The side of the metal substrate 9 to be polished faces the laser beam 2 of the focusing lens 1.

[0016] Step 5: Adjust the position of focusing lens 1 to the working focal length;

[0017] Step 6: Turn on the vacuum cleaner 7, the high-pressure gas cylinder 6 for protection gas, and the laser 12 in sequence, and adjust the parameters to perform polishing.

[0018] Step 7: Turn off the laser 12, high-pressure gas cylinder 6 and vacuum cleaner 7, clean the water tank 11 and the platform 10, and take out the sample for cleaning and drying.

[0019] Preferably, in step 1, the ultrasonic cleaning specifically involves ultrasonic cleaning with ethanol for 20-30 minutes; the material of the metal substrate is copper or aluminum conductive metal.

[0020] Preferably, in step 1, the drying temperature is 250–300°C and the drying time is 25–30 min.

[0021] Preferably, in step 1, the specific method of laser etching or etching solution etching is as follows: using a high-precision laser to etch micro-nano-scale uneven structures on the surface of the metal substrate 9, or treating the surface with acid or alkali solutions to form complex micro-nano-scale structures.

[0022] Preferably, in step 1, the oxidation treatment specifically involves introducing a hydrophilic oxide layer on the surface of the metal substrate 9 to enhance the superhydrophilic properties of the surface.

[0023] Preferably, in step 2, the coolant is a water-based coolant (such as deionized water, alcohol), fluorinated liquid, or silicone oil; the stage 10 is made of materials with good thermal conductivity, such as copper, aluminum, titanium, stainless steel, or aluminum alloy.

[0024] Preferably, in step 3, the ultrasonic cleaning specifically involves ultrasonic cleaning with ethanol for 20-30 minutes; and the sample is a high-temperature resistant metal or superalloy material such as a nickel-based high-temperature alloy, an iron-based high-temperature alloy, or an aluminum alloy; the drying temperature is 250-300°C, and the drying time is 25-30 minutes.

[0025] Preferably, in step 5, the working focal length of the focusing lens is 170-180mm.

[0026] Preferably, in step 6, the diameter D of the vacuum cleaner's pipe is 20-40mm, the air velocity at the hood opening is V1 = 0.4-0.6m / s, and the air velocity inside the hood is V2 < 3m / s.

[0027] The laser 12 used in this invention is a YAG solid-state laser, a CO2 pulsed laser, or a semiconductor laser; its laser wavelength range is 200nm to 10.6μm, and its output power range is 10% to 100%; a circular laser spot or a square laser spot is selected for laser processing, wherein the diameter of the circular laser spot is 1mm to 20mm, and the side length of the square laser spot is 1mm to 25mm; the pulse width range is 2ns to 400ns, the pulse frequency range is 10Hz to 5000kHz, the scanning speed range is 1000mm / s to 9000mm / s, the line spacing range is 0.01mm to 5mm, and the average laser power density ranges from 50W / cm². 2 ~500W / cm 2 The laser scanning path consists of two mutually orthogonal arc-shaped trajectories, each of which scans sequentially along a predetermined direction, and the scanning directions of the two arc-shaped trajectories are perpendicular to each other.

[0028] The present invention has the following advantages:

[0029] (1) Significantly improved heat dissipation efficiency: The device of the present invention greatly improves the wettability and heat transfer efficiency of the coolant by constructing a super-hydrophilic micro-nano structure on the surface of the metal-based heat sink, enabling it to quickly absorb and remove the heat generated during laser polishing. In addition, the device combines gas protection cooling and partial immersion cooling to achieve multi-dimensional synergistic heat dissipation. Compared with traditional single cooling technologies (such as gas cooling or liquid cooling), the heat dissipation efficiency is higher and the heat distribution is more uniform, ensuring that the temperature of the processing area is always within the ideal range.

[0030] (2) Precise thermal management: The device of the present invention integrates a real-time temperature monitoring and feedback system, which can monitor the temperature distribution of the processing area in real time through sensors, and automatically adjust the coolant flow rate and gas jet intensity according to the feedback, thereby achieving precise thermal management; in addition, the device focuses on local cooling of the processing area, avoiding the problems of overcooling or interference with the laser beam path caused by traditional liquid immersion cooling, ensuring that the processing process is more stable and controllable.

[0031] (3) Significantly improved processing quality: The device of the present invention forms an inert gas protective layer in the processing area through a gas protection system, which effectively prevents material oxidation or thermal damage caused by high temperature, thereby improving the smoothness and performance of the processed surface; in addition, the efficient heat dissipation and precise temperature control function of the device can avoid defects such as surface microcracks and deformation caused by heat accumulation, significantly reducing the roughness of the processed surface and greatly improving the overall processing quality.

[0032] (4) Strong applicability: The device of the present invention is applicable to a variety of metal materials (such as aluminum alloy, stainless steel, copper alloy, etc.) and can meet the processing needs of workpieces of different sizes and shapes. It has a wide range of applications, covering multiple fields such as aerospace, automobile manufacturing, and precision instruments. In addition, the device adopts a modular design, supports quick disassembly and flexible adjustment, and can be easily integrated into existing laser processing equipment to adapt to different laser power and process requirements, and has extremely strong industrial adaptability. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the laser polishing device combining gas protection and substrate heat dissipation according to the present invention.

[0034] Figure captions: 1-Focusing lens, 2-Laser beam, 3-Sample to be polished, 4-Gas nozzle, 5-Gas tube, 6-High-pressure gas cylinder, 7-Vacuum cleaner, 8-Coolant level, 9-Metal substrate, 10-Stage, 11-Water tank, 12-Laser. Detailed Implementation

[0035] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are merely further illustrations of the present invention, but the scope of protection of the present invention is not limited to the following embodiments.

[0036] Example 1

[0037] This example relates to a laser polishing apparatus that combines gas protection and substrate heat dissipation, see [link to example]. Figure 1 As shown, it includes: a focusing lens 1, a laser beam 2, a sample to be polished 3, a gas nozzle 4, a gas pipe 5, a high-pressure gas cylinder 6, a vacuum cleaner 7, a coolant surface 8, a metal substrate 9, a stage 10, a water tank 11, and a laser 12.

[0038] The surface of the metal substrate 9 is provided with a cooling liquid film consisting of a micro-nano structure and a hydrophilic oxide layer.

[0039] The stage 10 is placed inside the water tank 11, and the metal substrate 9 is placed at the upper end of the stage 10.

[0040] The sample 3 to be polished is placed on the metal substrate 9; the gas nozzle 4 and the vacuum cleaner 7 are respectively set at both ends of the sample 3 to be polished; the focusing lens 1 is suspended above the sample 3 to be polished.

[0041] The nozzle diameter of gas nozzle 4 is 5-10 mm, and the gas flow rate is controlled at 15-30 L / min.

[0042] This embodiment also relates to a method of using a laser polishing apparatus that combines gas protection and substrate heat dissipation, the specific steps of which are as follows:

[0043] Step 1: Place the smooth and flat copper plate sample, after ultrasonic cleaning with ethanol, into a drying oven and dry at 250°C for 25 minutes.

[0044] Step 2: Place the copper substrate, which has been pretreated by ultrasonic cleaning and drying, on the stage 10 of the laser. Use a nanosecond fiber laser to perform laser ablation on the sample surface. The laser wavelength is 1064nm, the maximum repetition frequency is 1000kHz, the pulse width is 4-200ns, the maximum scanning speed is 8000mm / s, and the maximum power is 20W. The laser processing is carried out in air, and the spot diameter on the target surface is 50μm during the processing.

[0045] Step 3: Immerse the etched copper plate in an ethanol solution to clean it and remove surface metal debris and impurities.

[0046] Step 4: Place the cleaned copper plate into a high-temperature furnace and heat it at 300°C for 60 minutes. After heating, allow the copper plate to cool naturally inside the furnace.

[0047] Step 5: Place the processed copper plate on the stage 10 in the water tank 11 of the laser 12, and add deionized water to just cover the copper plate.

[0048] Step 6: Cut the 2mm thick IN718 nickel-based alloy, which has been sandblasted with 8 mesh, into 20mm*20mm square plates.

[0049] Step 7: Place the cut IN718 sample in anhydrous ethanol and ultrasonically clean it for 25 minutes to remove surface metal debris and impurities.

[0050] Step 8: Place the cleaned IN718 sample in an oven and dry it at 250°C for 25 minutes.

[0051] Step 9: Take out the dried sample and place it in the center of the copper substrate in the laser water tank;

[0052] Step 10, turn on the vacuum cleaner 7;

[0053] Step 11: Turn on the argon gas and control the gas flow rate at 20 L / min.

[0054] Step 12: Turn on laser 12, set the power to 90W, the spacing to 0.15mm, and the linear speeds to 60mm / s, 90mm / s, 120mm / s, and 150mm / s respectively, and perform cross-scanning for each group of arc-shaped crosses;

[0055] Step 13: Turn off laser 12, argon gas and vacuum cleaner 7, and remove the sample.

[0056] Example 2

[0057] This example relates to a method of using a laser polishing apparatus that combines gas protection and substrate heat dissipation. The specific steps are as follows:

[0058] Step 1: Place the smooth and flat copper plate sample, after ultrasonic cleaning with ethanol, into a drying oven and dry at 250°C for 25 minutes.

[0059] Step 2: The copper substrate, after ultrasonic cleaning and drying pretreatment, is placed on the stage 10 of the laser 12. A nanosecond fiber laser is used to perform laser ablation on the sample surface. The laser wavelength is 1064nm, the maximum repetition frequency is 1000kHz, the pulse width is 4-200ns, the maximum scanning speed is 8000mm / s, and the maximum power is 20W. The laser processing is carried out in air, and the spot diameter on the target surface is 50μm during the processing.

[0060] Step 3: Immerse the etched copper plate in an ethanol solution to clean it and remove surface metal debris and impurities.

[0061] Step 4: Place the cleaned copper plate in a 3% hydrogen peroxide solution and let it stand for 15 minutes.

[0062] Step 5: After rinsing the processed copper plate with deionized water, place it on the stage 10 in the water tank 11 of the laser 12, and add deionized water until it just covers the copper plate.

[0063] Step 6: Cut the 2mm thick IN718 nickel-based alloy, which has been sandblasted with 8 mesh, into 20mm*20mm square plates.

[0064] Step 7: Place the cut IN718 sample in anhydrous ethanol and ultrasonically clean it for 25 minutes to remove surface metal debris and impurities.

[0065] Step 8: Place the cleaned IN718 sample in an oven and dry it at 250°C for 25 minutes.

[0066] Step 9: Take out the dried sample and place it in the center of the copper substrate in the water tank 11 of the laser 12.

[0067] Step 10, turn on the vacuum cleaner 7;

[0068] Step 11: Turn on the argon gas and control the gas flow rate at 20 L / min.

[0069] Step 12: Turn on laser 12, set the power to 90W, the spacing to 0.15mm, and the linear speeds to 60mm / s, 90mm / s, 120mm / s, and 150mm / s respectively, and perform cross-scanning for each group of arc-shaped crosses;

[0070] Step 13: Turn off laser 12, argon gas and vacuum cleaner, and remove the sample.

[0071] Example 3

[0072] This example relates to a method of using a laser polishing apparatus that combines gas protection and substrate heat dissipation. The specific steps are as follows:

[0073] Step 1: Place the smooth and flat copper plate sample, after ultrasonic cleaning with ethanol, into a drying oven and dry at 250°C for 25 minutes.

[0074] Step 2: Place the copper substrate, which has undergone ultrasonic cleaning and drying pretreatment, into a 25% nitric acid solution for etching for 5 minutes.

[0075] Step 3: Rinse the etched copper plate with deionized water to remove surface metal debris and impurities;

[0076] Step 4: Place the cleaned copper plate into a solution containing sodium hydroxide (NaOH): 0.5 mol / L: hydrogen peroxide (H2O2, 30%) at a volume ratio of 1:10 (i.e., 100 mL H2O2 is added to 1 L of NaOH solution) for oxidation treatment for 10 min, and then rinse with deionized water.

[0077] Step 5: Place the processed copper plate on the stage 10 in the water tank 11 of the laser 12, and add deionized water to just cover the copper plate.

[0078] Step 6: Cut the 2mm thick IN718 nickel-based alloy, which has been sandblasted with 8 mesh, into 20mm*20mm square plates.

[0079] Step 7: Place the cut IN718 sample in anhydrous ethanol and ultrasonically clean it for 25 minutes to remove surface metal debris and impurities.

[0080] Step 8: Place the cleaned IN718 sample in an oven and dry it at 250°C for 25 minutes.

[0081] Step 9: Take out the dried sample and place it in the center of the copper substrate in the water tank 11 of the laser 12.

[0082] Step 10, turn on the vacuum cleaner 7;

[0083] Step 11: Turn on the argon gas and control the gas flow rate at 20 L / min.

[0084] Step 12: Turn on laser 12, set the power to 90W, the spacing to 0.15mm, and the linear speeds to 60mm / s, 90mm / s, 120mm / s, and 150mm / s respectively, and perform cross-scanning for each group of arc-shaped crosses.

[0085] Step 13: Turn off laser 12, argon gas and vacuum cleaner 7, and remove the sample.

[0086] Example 4

[0087] This example relates to a method of using a laser polishing apparatus that combines gas protection and substrate heat dissipation. The specific steps are as follows:

[0088] Step 1: Place the smooth and flat copper plate sample, after ultrasonic cleaning with ethanol, into a drying oven and dry at 250°C for 25 minutes.

[0089] Step 2: Place the copper substrate, which has been ultrasonically cleaned and dried, into a solution of ferric chloride powder dissolved in deionized water at a mass ratio of 40%, and etch at a constant temperature of 40°C for 15 minutes.

[0090] Step 3: Rinse the etched copper plate with deionized water to remove surface metal debris and impurities;

[0091] Step 4: Immerse the cleaned copper plate in a 10% nitric acid solution for 2 minutes for oxidation treatment, and then rinse with deionized water.

[0092] Step 5: Place the processed copper plate on the stage 10 in the water tank 11 of the laser 12, and add deionized water to just cover the copper plate.

[0093] Step 6: Cut the 2mm thick IN718 nickel-based alloy, which has been sandblasted with 8 mesh, into 20mm*20mm square plates.

[0094] Step 7: Place the cut IN718 sample in anhydrous ethanol and ultrasonically clean it for 25 minutes to remove surface metal debris and impurities.

[0095] Step 8: Place the cleaned IN718 sample in an oven and dry it at 250°C for 25 minutes.

[0096] Step 9: Take out the dried sample and place it in the center of the copper substrate in the water tank 11 of the laser 12.

[0097] Step 10, turn on the vacuum cleaner 7;

[0098] Step 11: Turn on the argon gas and control the gas flow rate at 20 L / min.

[0099] Step 12: Turn on laser 12, set the power to 90W, the spacing to 0.15mm, and the linear speeds to 60mm / s, 90mm / s, 120mm / s, and 150mm / s respectively, and perform cross-scanning for each group of arc-shaped crosses.

[0100] Step 13: Turn off laser 12, argon gas and vacuum cleaner 7, and remove the sample.

[0101] In summary, to address the problems of heat accumulation, surface oxidation, and insufficient cooling efficiency during laser polishing, this invention proposes and develops a superhydrophilic micro / nanostructured metal-based heat dissipation device that combines gas-protected cooling and partial immersion cooling. This device significantly improves the wettability and heat dissipation efficiency of the coolant by constructing superhydrophilic micro / nano structures on the metal substrate surface. Simultaneously, the inert gas protection effectively prevents surface oxidation at high temperatures. Furthermore, the combined effect of the coolant and gas can rapidly reduce the temperature of the processing area, avoiding thermal damage and ensuring the stability of the laser path, thereby significantly improving processing efficiency and surface quality.

[0102] This invention's heat dissipation device is not only applicable to the laser polishing of IN718 nickel-based alloys, but can also be extended to the surface processing of other key materials in the aerospace field, such as titanium alloys, aluminum-lithium alloys, and high-performance composite materials. In the future, by combining intelligent sensing and automated control technologies, this device is expected to achieve real-time monitoring and dynamic adjustment of the processing process, further improving processing accuracy and reliability. As a green and efficient auxiliary technology, this device will provide crucial support for high-end manufacturing in the aerospace field and demonstrate broad application prospects in other high-end manufacturing sectors.

[0103] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method of using a laser polishing apparatus combining gas protection and substrate heat dissipation, characterized in that, Includes the following steps: Step 1: The untreated metal substrate is subjected to ultrasonic cleaning to remove surface dirt and oil stains, dried, laser etched or etched with etching solution, rinsed with deionized water to remove surface debris and impurities, and then placed in an oxidation solution for oxidation treatment. Step 2: Place the metal substrate (9) on the stage (10) and add coolant until a thin coolant film is formed on the surface of the metal substrate (9); Step 3: Clean the surface of the sample (3) to be polished by ultrasonic cleaning to remove dirt and oil stains, and then dry it; Step 4: Place the sample (3) to be polished after ultrasonic cleaning and drying pretreatment in the middle of the metal substrate (9) in the water tank (11), with the side of the sample (3) to be polished facing the laser beam (2) of the focusing lens (1). Step 5: Adjust the position of the focusing lens (1) to the working focal length; Step 6: Turn on the vacuum cleaner (7), the high-pressure gas cylinder (6) for protection gas, and the laser (12) in sequence, and adjust the parameters to perform polishing; Step 7: Turn off the laser (12), high-pressure gas cylinder (6) and vacuum cleaner (7), clean the water tank (11) and platform (10), and take out the sample for cleaning and drying; In step 1, the ultrasonic cleaning specifically involves ultrasonic cleaning with ethanol for 20-30 minutes; the material of the metal substrate is copper or aluminum; the drying temperature is 250-300℃ and the drying time is 25-30 minutes; the specific method of laser etching or etching solution etching is to use a high-precision laser to etch micro-nano-scale uneven structures on the surface of the metal substrate (9) or to process the surface with acid and alkali solutions to form complex micro-nano-scale structures; the specific oxidation treatment is to introduce a hydrophilic oxide layer on the surface of the metal substrate (9); In step 5, the inert gas used is any one or a combination of helium, neon and argon, the nozzle diameter is 5-10 mm, and the gas flow rate is controlled at 15-30 L / min. In step 6, the diameter D of the vacuum cleaner's pipe is 20-40mm, the air velocity at the hood opening is V1=0.4-0.6m / s, and the air velocity inside the hood is V2<3m / s. The laser polishing device used in this method, which combines gas protection and substrate heat dissipation, includes: a focusing lens (1), a laser beam (2), a sample to be polished (3), a gas nozzle (4), a gas pipe (5), a high-pressure gas cylinder (6), a vacuum cleaner (7), a coolant surface (8), a metal substrate (9), a stage (10), a water tank (11), and a laser (12). Among them, the surface of the metal substrate (9) is provided with a cooling liquid film composed of micro-nano-scale structure and hydrophilic oxide layer; The stage (10) is set inside the water tank (11), and the metal substrate (9) is set on the upper end of the stage (10); The sample to be polished (3) is placed on the metal substrate (9); the gas nozzle (4) and the vacuum cleaner (7) are respectively set at both ends of the sample to be polished (3); the focusing lens (1) is suspended above the sample to be polished (3).

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