An umbrella-shaped air-cooled based electrothermal film laser engraving anti-wrinkling device and a use method thereof

Abstract

This invention provides a device for preventing curling during laser engraving of an electrothermal thin film based on umbrella-shaped air cooling, and its usage method. The device includes: a focusing lens (1), an annular air-cooled nozzle (2), a laser beam (3), a PI substrate electrothermal thin film (4), an infrared temperature sensor (5), an air pipe (6), a vacuum pump (7), a laser (8), a high-pressure gas cylinder (9), an airflow regulator (10), a high-pressure air pipe (11), a stage (12), a high thermal conductivity flexible adsorption component (13), a protective cover (14), and an exhaust port (15). This invention also relates to the usage method of the device. This invention forms a full-coverage umbrella-shaped low-temperature protective airflow through the annular air-cooled nozzle, which, combined with the negative pressure adsorption effect of the high thermal conductivity flexible adsorption component and the vacuum pump, achieves non-damaging flat fixation and dual heat dissipation of the PI substrate electrothermal thin film. The infrared temperature sensor provides real-time temperature feedback and dynamically adjusts the air cooling parameters, thus solving the curling problem of laser engraving of the PI substrate electrothermal thin film.

Description

Technical Field

[0001] This invention relates to the field of electrothermal anti-icing processing technology for aircraft; and more particularly to an anti-curling device for electrothermal thin film laser engraving based on umbrella-shaped air cooling and its usage method. Background Technology

[0002] Laser engraving is a core technology for patterning electrothermal films on polyimide (PI) substrates. Leveraging its advantages of non-contact operation, high precision, and high efficiency, it is widely used in the fabrication of anti-icing / de-icing devices for surfaces in extreme environments of aerospace vehicles. PI-based electrothermal films are composed of a flexible PI substrate and electrothermal layers such as carbon nanotubes and graphite. However, during laser engraving, the localized instantaneous high temperature (300–500°C) of the laser beam causes significant thermal stress between the PI substrate and the carbon nanotube electrothermal layer due to the difference in their coefficients of thermal expansion. The coefficient of thermal expansion of the polyimide substrate is 20–30 ppm / °C, while that of the carbon nanotube electrothermal layer is only 0.5–1 ppm / °C. This significant difference in coefficients leads to uneven shrinkage upon cooling, easily causing deformation problems such as film curling and edge warping.

[0003] In existing technologies, cooling methods for laser processing are mostly static air cooling or overall water cooling. The cooling rate is uneven, which easily generates temperature gradient stress. It is difficult to quickly and accurately remove the instantaneous heat of the laser engraving area and suppress the generation of thermal stress from the source. Some solutions use complex composite constraint structures to assist in anti-curling, but rigid constraints are prone to damaging the ultra-thin polyimide substrate (<25μm), while flexible constraints are complex in structure, expensive, and lack linkage control between cooling and constraint, resulting in limited anti-curling effect.

[0004] Furthermore, the cooling parameters and laser processing parameters of traditional laser engraving devices are mostly fixed and cannot be dynamically adjusted according to the real-time temperature of the engraving area. This easily leads to heat accumulation or overcooling, which not only exacerbates film deformation but also causes carbonization and increased burrs at the edges of the engraved pattern, reduces the uniformity of the electrothermal layer resistance, and affects the processing quality and performance of the electrothermal film. Therefore, developing an anti-curling laser engraving device and its application method that uses umbrella-shaped air cooling as the core and combines it with highly thermally conductive flexible adsorption fixation to achieve real-time linkage between cooling and processing parameters has become a key technical problem that urgently needs to be solved in the field of patterned electrothermal film processing. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-curling device and method for laser engraving of electrothermal thin films based on umbrella-shaped air cooling. This invention solves the problems of curling, warping, low processing accuracy, and easy damage to the film in the existing laser engraving process of PI substrate electrothermal thin films, and achieves high-precision, high-flatness, and high-yield laser engraving processing of PI substrate electrothermal thin films.

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

[0007] This invention relates to an anti-curling device for laser engraving of an electrothermal thin film based on umbrella-shaped air cooling, comprising: a focusing lens 1, an annular air-cooled nozzle 2, a laser beam 3, a PI substrate electrothermal thin film 4, an infrared temperature sensor 5, an air pipe 6, an air pump 7, a laser 8, a high-pressure gas cylinder 9, an airflow regulator 10, a high-pressure air pipe 11, a stage 12, a high thermal conductivity flexible adsorption component 13, a protective cover 14, and an exhaust port 15.

[0008] Focusing lens 1 is used to focus the laser beam 3 onto the surface of the PI substrate electrothermal film 4;

[0009] Laser beam 3 is emitted by laser 8 and acts on PI substrate electrothermal film 4 through focusing lens 1;

[0010] The annular gas-cooled nozzle 2 is coaxially sleeved on the outside of the laser beam 3, and is used to convert the protective gas into a full-coverage umbrella-shaped cryogenic protective gas flow.

[0011] Infrared temperature sensor 5 is used to collect the temperature of the engraved area of ​​the PI substrate electrothermal film 4 in real time.

[0012] The air tube 6 is connected to the air pump 7 and the stage 12 respectively to form a negative pressure adsorption channel.

[0013] The vacuum pump 7 is used to provide the negative pressure adsorption power;

[0014] Laser 8 is used to generate a high-energy laser beam;

[0015] High-pressure gas cylinder 9 is used to store inert protective gas;

[0016] The airflow regulator 10 is used to stabilize the pressure and flow rate of the protective gas;

[0017] One end of the high-pressure gas pipe 11 is an annular air-cooled nozzle 2, and the other end is connected to the airflow regulator 10 and the high-pressure gas cylinder 9, which are used to transport protective gas.

[0018] The stage 12 is used to support the high thermal conductivity flexible adsorption component 13, and an air extraction channel is opened inside it.

[0019] A highly thermally conductive flexible adsorption component 13 is laid on the upper surface of the stage 12 for placing and flexibly bonding the PI substrate electrothermal film 4.

[0020] The high thermal conductivity flexible adsorption component 13 is a double-layer composite structure of a hollow aluminum alloy substrate 13-1 and a porous thermally conductive graphite pad 13-2.

[0021] The protective cover 14 is located on the outside of the core processing component to isolate the processing area;

[0022] The exhaust port 15 is located on the side wall of the protective cover 14 to balance the air pressure inside the cover;

[0023] The annular air-cooled nozzle 2 has a coaxial single-channel gradient structure; it has a conical guide cone at the center and 60 to 80 gradient oblique air outlet holes evenly distributed along the lower circumference.

[0024] The angle between the gradually angled air outlet and the horizontal direction is 45° to 60°, and the diameter of the outlet gradually changes from an inner circle of 0.2 mm to an outer circle of 0.4 mm; the vertical distance between the air outlet of the annular air-cooled nozzle 2 and the surface of the PI substrate electrothermal film 4 is 8 to 10 mm.

[0025] The through holes between the hollow aluminum alloy substrate 13-1 and the porous thermally conductive graphite pad 13-2 are precisely aligned;

[0026] The mesh-like perforated channel of the hollowed-out aluminum alloy base 13-1 is connected to the internal air extraction channel of the stage 12.

[0027] The hollowed-out aluminum alloy substrate 13-1 is made of 6061-T6 material, with a thermal conductivity ≥155W / (m·K) and a hollowing rate of 35%~40%; the porous thermally conductive graphite pad 13-2 is a flexible graphite composite material with a pore size of 5~10μm, a porosity of 40%~45%, a thermal conductivity ≥120W / (m·K), and a temperature resistance range ≥500℃.

[0028] Preferably, the upper surface edge of the stage 12 is provided with a silicone elastic edge strip; wherein the height of the silicone elastic edge strip is 0.3-0.5mm and the Shore hardness is 60HA; the exhaust port 15 is an adjustable structure.

[0029] Preferably, the infrared temperature sensor 5 has a temperature measurement range of 0 to 600℃ and a temperature measurement accuracy of ±0.1℃; a high thermal conductivity ceramic airflow shield is fitted on its outer side, and the shield has a φ2mm temperature measurement through hole.

[0030] Preferably, the laser 8 is an ultraviolet picosecond / femtosecond laser with a wavelength of 355nm / 1064nm, a pulse width of <10ps, a heat-affected zone of <5μm, and is equipped with a high-speed galvanometer scanning system with a scanning speed of ≥5000mm / s and a positioning accuracy of ±1μm.

[0031] Preferably, the high-pressure gas cylinder 9 stores argon or nitrogen as an inert protective gas.

[0032] The air supply pressure adjustment range of the airflow regulator 10 is 0.2 to 0.5 MPa, and the protective gas flow rate is linearly linked to the air supply pressure: 0.2 MPa corresponds to a flow rate of 8 to 10 L / min, 0.3 to 0.4 MPa corresponds to a flow rate of 12 to 16 L / min, and 0.5 MPa corresponds to a flow rate of 18 to 20 L / min.

[0033] The air pump (7) is an oil-free vortex air pump with an air flow rate adjustment range of 10-20 L / min and a negative pressure adjustment range of 0.05-0.1 MPa.

[0034] The present invention also relates to a method of using the aforementioned umbrella-shaped air-cooled electrothermal thin film laser engraving anti-curling device, comprising the following steps:

[0035] Step 1: Clean the surface of the PI substrate electrothermal film 4 with ultrasonic cleaning to remove dirt and oil stains, and then dry it.

[0036] Step 2: Place the PI substrate electrothermal film 4 in the middle of the upper surface of the high thermal conductivity flexible adsorption component 13, with the side to be engraved aligned with the laser beam 3 of the focusing lens 1.

[0037] Step 3: Adjust the position of focusing lens 1 to the working focal length;

[0038] Step 4: Open the high-pressure gas cylinder 9 and the airflow regulator 10 for the protective gas, adjust the gas flow rate and control the introduction time to exhaust the residual air in the high-pressure gas pipe and the annular air-cooling nozzle, and at the same time use the low-temperature protective gas to form an umbrella-shaped airflow to pre-cool the PI substrate electrothermal film 4.

[0039] Step 5: Turn on laser 8 and modulate the parameters to perform engraving;

[0040] Step 6: Turn off the laser 8, high-pressure gas cylinder 9 and airflow regulator 10, maintain the negative pressure adsorption state of the vacuum pump 7 for a period of time, then turn off the vacuum pump 7, clean the stage 12 and the high thermal conductivity flexible adsorption component 13, and take out the sample for cleaning and drying.

[0041] Preferably, in step 1, the ultrasonic cleaning specifically involves ultrasonic cleaning with anhydrous ethanol for 20–30 min; the drying temperature is 250–300 °C, and the drying time is 25–30 min; the PI substrate of the PI substrate electrothermal film 4 has a PI substrate thickness of 12.5–50 μm, an electrothermal layer thickness of 1–5 μm, and the electrothermal layer material is carbon nanotubes or graphite.

[0042] Preferably, in step 4, the gas flow rate is 12-16 L / min, the air purging time is not less than 4 min, and the pre-cooling temperature is 20-25℃.

[0043] Preferably, in step 5, the processing parameters of the laser 8 are: power 5-15W, scanning speed 3000-8000mm / s, pulse frequency 100-500kHz, and engraving depth 5-15μm; during the engraving process, the infrared temperature sensor 5 collects the temperature in real time and keeps the temperature fluctuation of the engraving area ≤±2℃.

[0044] Preferably, in step 6, the adsorption time is 8-12 minutes; the cleaning specifically involves ultrasonic cleaning with deionized water at 50W power for 5 minutes; and the drying temperature is 60°C, and the drying time is 15 minutes.

[0045] The present invention has the following advantages:

[0046] (1) Significantly improved heat dissipation efficiency: The present invention forms a full-coverage umbrella-shaped low-temperature protective airflow through an annular air-cooling nozzle, and with the contact-assisted heat conduction of the high thermal conductivity flexible adsorption component, a dual heat dissipation system of "air cooling + contact heat conduction" is formed, which quickly dissipates the heat of the film and suppresses the generation of thermal stress from the source. The heat dissipation efficiency is improved by more than 30% compared with the traditional single cooling method, and the curvature of the film after engraving is ≤0.6mm / m.

[0047] (2) Precise thermal management: The present invention integrates an infrared temperature sensor and a dynamic adjustment system. The sensor monitors the temperature change of the processing area in real time and automatically adjusts the air cooling pressure and flow rate according to the feedback to achieve precise thermal management, keep the temperature fluctuation of the engraving area ≤ ±2℃, and avoid processing defects caused by heat accumulation or overcooling.

[0048] (3) Significantly improved processing quality: The present invention effectively prevents the oxidation of the material surface at high temperature by inert gas protection, avoiding thermal damage; the high thermal conductivity flexible adsorption component realizes the flat fixation of the film without damage, and with the high precision laser processing, the engraved pattern line width accuracy is within ±1μm, the edge is free of carbonization and burrs, the electric heating layer resistance is uniform, and the processing quality is greatly improved.

[0049] (4) Strong applicability: The device of this invention is applicable to PI substrate electrothermal films with different thicknesses from 12.5 to 50 μm, and is compatible with various electrothermal layer materials such as carbon nanotubes and graphite. It has a wide range of applications, covering multiple fields such as aerospace, flexible electronics, and new energy. The device adopts a modular design, with a simple structure and convenient operation. It can be easily integrated into existing laser processing equipment and has extremely strong industrial adaptability. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the overall structure of the umbrella-shaped air-cooled electrothermal thin film laser engraving anti-curling device of the present invention;

[0051] Figure 2 This is a schematic diagram of the structure of the high thermal conductivity flexible adsorption component involved in this invention;

[0052] Figure labels: 1-Focusing lens, 2-Annular air-cooled nozzle, 3-Laser beam, 4-PI substrate electrothermal film, 5-Infrared temperature sensor, 6-Gas tube, 7-Air pump, 8-Laser, 9-High-pressure gas cylinder, 10-Airflow regulator, 11-High-pressure gas tube, 12-Stage, 13-High thermal conductivity flexible adsorption component, 14-Protective cover, 15-Exhaust port, 13-1 Hollowed-out aluminum alloy substrate, 13-2 Porous thermally conductive graphite pad. Detailed Implementation

[0053] 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.

[0054] Example 1

[0055] This embodiment relates to an anti-curling device for electrothermal thin film laser engraving based on umbrella-shaped air cooling, see [link to documentation]. Figure 1 As shown, it includes a focusing lens 1, an annular air-cooled nozzle 2, a laser beam 3, a PI substrate electrothermal film 4, an infrared temperature sensor 5, an air tube 6, a vacuum pump 7, a laser 8, a high-pressure gas cylinder 9, an airflow regulator 10, a high-pressure air tube 11, a stage 12, a high thermal conductivity flexible adsorption component 13, a protective cover 14, and an exhaust port 15.

[0056] The high thermal conductivity flexible adsorption component 13 is composed of a hollow aluminum alloy base 13-1 and a porous thermally conductive graphite pad 13-2. The through holes of the two are precisely aligned and laid on the upper surface of the stage 12. The stage 12 is connected to the air pump 7 through the air pipe 6, and the edge is provided with a silicone elastic pressing strip. The annular air-cooled nozzle 2 is coaxially sleeved on the outside of the laser beam 3, and is connected to the airflow regulator 10 and the high-pressure gas cylinder 9 in sequence through the high-pressure air pipe 11. The protective cover 14 is covered on the outside of the core component, and the side wall is provided with an infrared temperature sensor 5 and an exhaust port 15.

[0057] Step 1: Cut the 25μm thick PI substrate + 3μm thick carbon nanotube electrothermal layer film into 50mm pieces. 50mm square sample;

[0058] Step 2: Place the sample in anhydrous ethanol and ultrasonically clean it for 25 minutes to remove surface impurities;

[0059] Step 3: Place the cleaned sample in an oven at 280℃ and dry for 28 minutes;

[0060] Step 4: Take out the dried sample and place it in the center of the high thermal conductivity flexible adsorption component 13, with the silicone elastic pressing strip attached to the edge of the sample.

[0061] Step 5: Open argon cylinder 9 and gas flow regulator 10, control the gas flow rate at 15L / min, continuously introduce gas for 4 minutes to purge air and pre-cool, so that the sample temperature drops to 22℃.

[0062] Step 6: Adjust the focusing lens 1 to the working focal length, start the infrared temperature sensor 5, turn on the laser 8, set the power to 8W, the scanning speed to 5000mm / s, the pulse frequency to 200kHz, and the engraving depth to 8μm, and perform an arc-shaped cross-scan with a line spacing of 0.1~0.15mm.

[0063] Step 7: After the engraving is completed, turn off the laser 8, argon cylinder 9 and airflow regulator 10, and maintain the negative pressure adsorption state of the vacuum pump 7 for 10 minutes.

[0064] Step 8: Turn off the vacuum pump 7, take out the sample, ultrasonically clean it with deionized water at 50W power for 5 minutes, and then dry it in a vacuum drying oven at 60℃ for 15 minutes.

[0065] Example 2

[0066] This example relates to an anti-curling device for laser engraving of an electrothermal thin film based on umbrella-shaped air cooling, see [link to documentation]. Figure 1 As shown, it includes a focusing lens 1, an annular air-cooled nozzle 2, a laser beam 3, a PI substrate electrothermal film 4, an infrared temperature sensor 5, an air tube 6, a vacuum pump 7, a laser 8, a high-pressure gas cylinder 9, an airflow regulator 10, a high-pressure air tube 11, a stage 12, a high thermal conductivity flexible adsorption component 13, a protective cover 14, and an exhaust port 15.

[0067] The high thermal conductivity flexible adsorption component 13 is composed of a hollow aluminum alloy base 13-1 and a porous thermally conductive graphite pad 13-2. The through holes of the two are precisely aligned and laid on the upper surface of the stage 12. The stage 12 is connected to the air pump 7 through the air pipe 6, and the edge is provided with a silicone elastic pressing strip. The annular air-cooled nozzle 2 is coaxially sleeved on the outside of the laser beam 3, and is connected to the airflow regulator 10 and the high-pressure gas cylinder 9 in sequence through the high-pressure air pipe 11. The protective cover 14 is covered on the outside of the core component, and the side wall is provided with an infrared temperature sensor 5 and an exhaust port 15.

[0068] Step 1: Cut the 12.5μm thick ultrathin PI substrate + 1μm thick carbon nanotube electrothermal layer film into 50mm pieces. 50mm square sample;

[0069] Step 2: Place the sample in anhydrous ethanol and ultrasonically clean it for 20 minutes to remove surface impurities;

[0070] Step 3: Place the cleaned sample in an oven at 250℃ and dry for 25 minutes;

[0071] Step 4: Take out the dried sample and place it in the center of the high thermal conductivity flexible adsorption component 13, with the silicone elastic pressing strip attached to the edge of the sample.

[0072] Step 5: Open argon cylinder 9 and gas flow regulator 10, control the gas flow rate at 12L / min, continuously introduce gas for 4 minutes to purge the air and pre-cool the sample to reduce the temperature to 20℃.

[0073] Step 6: Adjust the focusing lens 1 to the working focal length, start the infrared temperature sensor 5, turn on the laser 8, set the power to 5W, the scanning speed to 3000mm / s, the pulse frequency to 100kHz, and the engraving depth to 5μm, and perform an arc-shaped cross-scan with a line spacing of 0.1~0.15mm.

[0074] Step 7: After the engraving is completed, turn off the laser 8, argon cylinder 9 and airflow regulator 10, and maintain the negative pressure adsorption state of the vacuum pump 7 for 8 minutes.

[0075] Step 8: Turn off the vacuum pump 7, take out the sample, ultrasonically clean it with deionized water at 50W power for 5 minutes, and then dry it in a vacuum drying oven at 60℃ for 15 minutes.

[0076] Example 3

[0077] This example relates to an anti-curling device for laser engraving of an electrothermal thin film based on umbrella-shaped air cooling, see [link to documentation]. Figure 1 As shown, it includes a focusing lens 1, an annular air-cooled nozzle 2, a laser beam 3, a PI substrate electrothermal film 4, an infrared temperature sensor 5, an air tube 6, a vacuum pump 7, a laser 8, a high-pressure gas cylinder 9, an airflow regulator 10, a high-pressure air tube 11, a stage 12, a high thermal conductivity flexible adsorption component 13, a protective cover 14, and an exhaust port 15.

[0078] The high thermal conductivity flexible adsorption component 13 is composed of a perforated aluminum alloy substrate 13-1 and a porous thermally conductive graphite pad 13-2. Figure 2 As shown, the two through holes are precisely aligned and laid on the upper surface of the stage 12; the stage 12 is connected to the air pump 7 through the air pipe 6, and the edge is provided with a silicone elastic pressing strip; the annular air-cooled nozzle 2 is coaxially sleeved on the outside of the laser beam 3, and is connected to the airflow regulator 10 and the high-pressure gas cylinder 9 in sequence through the high-pressure air pipe 11; the protective cover 14 is covered on the outside of the core component, and the side wall is provided with an infrared temperature sensor 5 and an exhaust port 15.

[0079] Step 1: Cut the 50μm thick PI substrate + 5μm thick graphite electrothermal layer film into 50mm pieces. 50mm square sample;

[0080] Step 2: Place the sample in anhydrous ethanol and ultrasonically clean it for 30 minutes to remove surface impurities;

[0081] Step 3: Place the cleaned sample in an oven at 300℃ and dry for 30 minutes;

[0082] Step 4: Take out the dried sample and place it in the center of the high thermal conductivity flexible adsorption component 13, with the silicone elastic pressing strip attached to the edge of the sample.

[0083] Step 5: Open nitrogen cylinder 9 and gas flow regulator 10, control the gas flow rate at 18L / min to enhance the pre-cooling effect, and continue to purge the air for 4 minutes to pre-cool the sample and reduce the sample temperature to 25℃.

[0084] Step 6: Adjust the focusing lens 1 to the working focal length, start the infrared temperature sensor 5, turn on the laser 8, set the power to 15W, the scanning speed to 8000mm / s, the pulse frequency to 500kHz, and the engraving depth to 15μm, and perform an arc-shaped cross-scan with a line spacing of 0.1~0.15mm.

[0085] Step 7: After the engraving is completed, turn off the laser 8, nitrogen cylinder 9 and airflow regulator 10, and maintain the negative pressure adsorption state of the vacuum pump 7 for 12 minutes.

[0086] Step 8: Turn off the vacuum pump 7, take out the sample, ultrasonically clean it with deionized water at 50W power for 5 minutes, and then dry it in a vacuum drying oven at 60℃ for 15 minutes.

[0087] In summary, to address the technical challenges of heat accumulation, surface oxidation, and curling deformation during laser engraving of PI substrate electrothermal thin films, this invention proposes and develops an anti-curling device for electrothermal thin film laser engraving based on umbrella-shaped gas cooling and its application method. This device innovatively combines umbrella-shaped gas cooling with high thermal conductivity flexible adsorption fixation technology to create a highly efficient heat dissipation environment on the film surface, significantly improving cooling efficiency and ensuring temperature stability in the processing area. Simultaneously, the inert gas protection effectively prevents oxidation of the material surface at high temperatures, avoiding thermal damage and thus ensuring the stability and continuity of laser engraving.

[0088] This invention not only significantly improves the processing efficiency and surface quality of laser engraving on PI substrate electrothermal thin films, but also adapts to the processing of thin films with different thicknesses and electrothermal layer materials. By combining intelligent sensing technology with an automated control system, this device is expected to achieve real-time monitoring and dynamic adjustment of the processing process in the future, further improving processing accuracy, reliability, and ease of operation. Furthermore, as a green and efficient processing aid technology, this device can reduce energy consumption and environmental pollution, providing crucial support for high-end manufacturing in the aerospace field, while also showing broad application prospects in other high-end manufacturing fields such as flexible electronics, consumer electronics, and new energy.

[0089] 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 device for laser engraving anti-curling of electrothermal thin films based on umbrella-shaped air cooling, characterized in that, include: Focusing lens (1), annular air-cooled nozzle (2), laser beam (3), PI substrate electrothermal film (4), infrared temperature sensor (5), air tube (6), air pump (7), laser (8), high-pressure gas cylinder (9), airflow regulator (10), high-pressure air tube (11), stage (12), high thermal conductivity flexible adsorption component (13), protective cover (14), exhaust port (15); A focusing lens (1) is used to focus the laser beam (3) onto the surface of the PI substrate electrothermal film (4); The laser beam (3) is emitted by the laser (8) and acts on the PI substrate electrothermal film (4) through the focusing lens (1); The annular gas-cooled nozzle (2) is coaxially sleeved on the outside of the laser beam (3) to convert the protective gas into a full-coverage umbrella-shaped low-temperature protective gas flow. Infrared temperature sensor (5) is used to collect the temperature of the engraved area of ​​the PI substrate electrothermal film (4) in real time; The air tube (6) is connected to the air pump (7) and the stage (12) respectively to form a negative pressure adsorption channel; The vacuum pump (7) is used to provide negative pressure adsorption power; The laser (8) is used to generate a high-energy laser beam; High-pressure gas cylinders (9) are used to store inert protective gases; The airflow regulator (10) is used to stabilize the pressure and flow rate of the protective gas; One end of the high-pressure gas pipe (11) has an annular air-cooled nozzle (2), and the other end is connected to a gas flow regulator (10) and a high-pressure gas cylinder (9) for conveying protective gas; The stage (12) is used to support the high thermal conductivity flexible adsorption component (13), and an air extraction channel is opened inside; A highly thermally conductive flexible adsorption component (13) is laid on the upper surface of the stage (12) for placing and flexibly bonding the PI substrate electrothermal film (4). The high thermal conductivity flexible adsorption component (13) is a double-layer composite structure of a hollow aluminum alloy substrate (13-1) and a porous thermally conductive graphite pad (13-2); The protective cover (14) is located on the outside of the core processing component to isolate the processing area; The exhaust port (15) is located on the side wall of the protective cover (14) to balance the air pressure inside the cover; The annular air-cooled nozzle (2) has a coaxial single-channel gradient structure; the center of the interior is provided with a conical guide cone, and 60 to 80 gradient oblique air outlet holes are uniformly provided along the lower circumference. Among them, the angle between the gradually angled air outlet and the horizontal direction is 45° to 60°, and the diameter of the outlet gradually changes from 0.2mm inner circle to 0.4mm outer circle; the vertical distance between the air outlet of the annular air-cooled nozzle (2) and the surface of the PI substrate electrothermal film (4) is 8 to 10mm. The through holes between the hollow aluminum alloy substrate (13-1) and the porous thermally conductive graphite pad (13-2) are precisely aligned; The mesh-like hollow channel of the hollow aluminum alloy base (13-1) is connected to the internal air extraction channel of the stage (12); The perforated aluminum alloy substrate (13-1) is made of 6061-T6 material with a thermal conductivity ≥155W / (m·K) and a perforation rate of 35%~40%; the porous thermally conductive graphite pad (13-2) is a flexible graphite composite material with a pore size of 5~10μm, a porosity of 40%~45%, a thermal conductivity ≥120W / (m·K), and a temperature resistance range ≥500℃.

2. The anti-curling device for electrothermal thin film laser engraving based on umbrella-shaped air cooling as described in claim 1, characterized in that, The upper surface edge of the stage (12) is provided with a silicone elastic edge strip; wherein the height of the silicone elastic edge strip is 0.3 to 0.5 mm and the Shore hardness is 60 HA; the exhaust port (15) is an adjustable structure.

3. The anti-curling device for electrothermal thin film laser engraving based on umbrella-shaped air cooling as described in claim 1, characterized in that, The infrared temperature sensor (5) has a temperature measurement range of 0 to 600℃ and a temperature measurement accuracy of ±0.1℃; a high thermal conductivity ceramic airflow shield is fitted on its outer side, and the shield has a φ2mm temperature measurement through hole.

4. The anti-curling device for electrothermal thin film laser engraving based on umbrella-shaped air cooling as described in claim 1, characterized in that, The laser (8) is an ultraviolet picosecond / femtosecond laser with a wavelength of 355nm / 1064nm, a pulse width of <10ps, a heat-affected zone of <5μm, and is equipped with a high-speed galvanometer scanning system with a scanning speed of ≥5000mm / s and a positioning accuracy of ±1μm.

5. The anti-curling device for electrothermal thin film laser engraving based on umbrella-shaped air cooling as described in claim 1, characterized in that, The high-pressure gas cylinder (9) stores argon or nitrogen as an inert protective gas. The gas supply pressure adjustment range of the gas flow regulator (10) is 0.2 to 0.5 MPa, and the protective gas flow rate is linearly linked with the gas supply pressure: 0.2 MPa corresponds to a flow rate of 8 to 10 L / min, 0.3 to 0.4 MPa corresponds to a flow rate of 12 to 16 L / min, and 0.5 MPa corresponds to a flow rate of 18 to 20 L / min. The air pump (7) is an oil-free vortex air pump with an air flow rate adjustment range of 10-20 L / min and a negative pressure adjustment range of 0.05-0.1 MPa.

6. A method of using the umbrella-shaped air-cooled electrothermal thin film laser engraving anti-curling device as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Clean the surface of the PI substrate electrothermal film (4) with ultrasonic cleaning to remove dirt and oil stains, and then dry it; Step 2: Place the PI substrate electrothermal film (4) in the middle of the upper surface of the high thermal conductivity flexible adsorption component (13), with the side to be engraved aligned with the laser beam (3) direction of the focusing lens (1). Step 3, adjust the position of the focusing lens (1) to the working focal length; Step 4: Open the high-pressure gas cylinder (9) and the airflow regulator (10) of the protective gas, adjust the gas flow rate and control the introduction time to exhaust the residual air in the high-pressure gas pipe and the annular air-cooling nozzle, and at the same time use the low-temperature protective gas to form an umbrella-shaped airflow to pre-cool the PI substrate electrothermal film (4). Step 5: Turn on the laser (8) and modulate the parameters to perform engraving; Step 6: Turn off the laser (8), high-pressure gas cylinder (9) and airflow regulator (10), keep the vacuum pump (7) in negative pressure adsorption state for a period of time, then turn off the vacuum pump (7), clean the stage (12) and the high thermal conductivity flexible adsorption component (13), and take out the sample for cleaning and drying.

7. The method of using the umbrella-shaped air-cooled electrothermal thin film laser engraving anti-curling device as described in claim 6, characterized in that, In step 1, the ultrasonic cleaning specifically involves ultrasonic cleaning with anhydrous ethanol for 20-30 minutes; the drying temperature is 250-300℃ and the drying time is 25-30 minutes; the PI substrate of the PI substrate electrothermal film (4) has a thickness of 12.5-50 μm, an electrothermal layer thickness of 1-5 μm, and the electrothermal layer material is carbon nanotube or graphite.

8. The method of using the umbrella-shaped air-cooled electrothermal thin film laser engraving anti-curling device as described in claim 6, characterized in that, In step 4, the gas flow rate is 12-16 L / min, and the air purging time is not less than 4 min; the pre-cooling temperature is 20-25℃.

9. The method of using the umbrella-shaped air-cooled electrothermal thin film laser engraving anti-curling device as described in claim 6, characterized in that, In step 5, the processing parameters of the laser (8) are: power 5-15W, scanning speed 3000-8000mm / s, pulse frequency 100-500kHz, and engraving depth 5-15μm. During the engraving process, the infrared temperature sensor (5) collects the temperature in real time and keeps the temperature fluctuation of the engraving area ≤±2℃.

10. The method of using the umbrella-shaped air-cooled electrothermal thin film laser engraving anti-curling device as described in claim 6, characterized in that, In step 6, the adsorption time is 8-12 minutes; the cleaning process specifically involves ultrasonic cleaning with deionized water at 50W power for 5 minutes; the drying temperature is 60℃ and the drying time is 15 minutes.

Images