A high-precision surface laser double polishing method for fused quartz

Abstract

The application discloses a fused quartz high-precision surface laser double-face polishing method, and belongs to the technical field of optical element laser processing. In order to solve the problem of surface shape distortion of a fused quartz element under the existing laser polishing process, the method comprises the following steps: firstly, the fused quartz element is subjected to ultrasonic cleaning and dried by compressed air; the fused quartz appearance distribution after laser polishing is simulated through finite element simulation, and the scanning speed is optimized; then, the target surface is polished according to the process parameters and the machining path after the scanning speed is optimized; the internal temperature distribution of the fused quartz after laser polishing is obtained through finite element simulation, and the polishing power of elements with different thicknesses is optimized; the back surface of the target surface is polished by using the optimized laser power; and ultrasonic cleaning and drying are carried out again after laser polishing. The method has simple process and low cost, can significantly improve the surface shape quality and reduce the roughness, avoids the time cost of parameter cross experiment, and efficiently realizes the optimization of laser polishing parameters.

Description

Technical Field

[0001] This invention belongs to the field of optical component processing and manufacturing, and in particular, it is a method for high-precision laser double-sided polishing of fused silica surfaces. Background Technology

[0002] Fused silica glass is widely used in high-tech and modern industrial fields due to its excellent thermal, chemical, optical, and mechanical properties. In high-power laser systems, fused silica glass, with its wide bandgap, is the preferred material for core components such as windows, focusing lenses, and diffraction gratings. Theoretical calculations show that the intrinsic surface damage threshold of fused silica glass components can reach 100 J / cm². 2 This demonstrates that the intrinsic surface of fused silica optical components without any processing defects can meet the requirements of high-power laser systems. However, while the current mainstream mechanochemical polishing methods for fused silica glass can achieve low surface roughness, they introduce defects such as cracks, scratches, and contaminants on the processed surface, becoming the source of laser absorption and component damage. Therefore, it is necessary to invent a method to remove surface defects and contaminants and improve surface processing quality. Laser polishing has the advantages of no polishing aids, non-contact processing, and no introduction of surface defects or polishing hydrolysis impurities, giving it a natural advantage in controlling processing defects. Currently, the surface roughness of laser-polished components is superior to that of traditional polishing. However, after laser polishing, components are affected by temperature fluctuations, leaving ablation ripples on the surface, and residual stress can lead to surface distortion, which greatly deteriorates surface accuracy and limits further technological development.

[0003] Patent document CN 109693039 A discloses a method for laser polishing of silicon wafer surfaces, which improves surface roughness quality through surface laser polishing. The drawback of this process is that it employs a single-sided laser polishing process, which, while reducing surface roughness, severely degrades the surface shape. This problem is also present in the vast majority of laser polishing patents; they only focus on the surface roughness quality after processing, neglecting the larger-scale surface accuracy issue, thus limiting the improvement of precision in laser-polished fused silica components.

[0004] Patent document CN109590603A discloses a polishing method for fused silica optical glass, which achieves a surface roughness of 0.18 nm by utilizing a temperature control feedback system and an annealing process. The drawback of this method is that the annealing process is very complex and time-consuming. Although it can eliminate residual thermal stress, the release of thermal stress after the annealing process severely damages the surface shape of the component, causing surface distortion.

[0005] Patent document CN114149180A discloses a multi-physics field laser polishing method and equipment for brittle materials. This technical solution uses ultrasonic vibration to assist laser polishing, thereby overcoming the tendency for pores and cracks to form in the molten pool. The drawback of this solution is that it primarily focuses on pores and cracks, neglecting processing precision. Furthermore, while ultrasonic assistance can suppress the formation of pores and cracks, it cannot eliminate the severe surface distortion caused by thermal stress introduced during laser polishing.

[0006] Based on the above analysis, existing laser polishing methods struggle to simultaneously meet the surface shape and roughness requirements of CO2 laser polishing of fused silica. Furthermore, current polishing techniques cannot efficiently obtain the optimal parameters for laser polishing from these complex physical processes. CO2 laser polishing of fused silica involves a series of complex physical processes, including the absorption, evaporation, and irradiation of laser energy by the fused silica material, material viscoelasticity, melt flow, surface tension, and the Marangoni effect. Traditional cross-parameter experimental methods are extremely time-consuming. Therefore, it is essential to develop new polishing processes that incorporate finite element simulation models and consider the complex physical processes involved in laser polishing to ensure the accuracy of both surface shape and roughness. Summary of the Invention

[0007] The purpose of this invention is to propose a high-precision laser double-sided polishing method for fused silica surfaces, addressing the shortcomings of the aforementioned techniques. The method provided by this invention can significantly alleviate surface distortion and improve surface roughness during the polishing process. This method is simple to operate, low in cost, and expands the application scenarios of laser polishing.

[0008] The technical solution of this invention is to propose a method for high-precision laser double-sided polishing of fused silica surfaces, which mainly includes the following steps:

[0009] S1. Rinse the fused silica element in deionized water, then sonicate it in pure water at a temperature of 20-30℃ for 10-15 minutes, rinse it with deionized water again, and finally dry it with compressed air to obtain a clean fused silica surface.

[0010] S2. The scanning speed of the target surface is optimized. The surface contour evolution and roughness of the fused quartz element after CO2 laser polishing are simulated by finite element simulation at different scanning speeds. The fitting curve of scanning speed and surface roughness is obtained, and then the scanning speed under minimum roughness is determined.

[0011] S3. Place the fused silica element on the moving platform, set the laser polishing parameters and scanning path, and adjust the polishing starting point position. Process the target surface according to the scanning speed set in step S2.

[0012] S4. The polishing power on the back side of the target surface is optimized. The thermodynamic temperature distribution inside the fused silica element after polishing with CO2 laser at different power is calculated by finite element simulation. The temperature of both the target surface and the back side of the target surface exceeds the melting temperature of the material (1800K) and is lower than the evaporation temperature of the material (2500K). The fitting curve of element thickness and laser power is then obtained.

[0013] S5. Change the laser processing surface to the back of the target surface, measure the component thickness, select the laser power for polishing according to the fitting curve of component thickness and laser power in step S4, and keep other polishing parameters and scanning path consistent with step S3.

[0014] S6. Ultrasonic cleaning of fused silica elements: First rinse with deionized water, then sonicate in pure water at a temperature of 20-30℃ for 10-15 minutes, rinse with deionized water again, and finally dry on an ultra-clean workbench to obtain ultrasonically cleaned fused silica elements.

[0015] The specific steps of the finite element simulation described in step S2 are as follows:

[0016] S2.1 takes into account the influence of material properties on polishing effect with temperature change. Based on experimental measurements, the specific heat capacity coefficient, viscosity coefficient and thermal conductivity coefficient of fused silica with temperature change are obtained, and the three coefficients are set as parameters of material properties in finite element simulation.

[0017] The expression for the specific heat capacity coefficient of fused silica is:

[0018]

[0019] The expression for the viscosity coefficient of fused silica is:

[0020]

[0021] The expression for the thermal conductivity of fused silica is:

[0022]

[0023] S2.2 takes into account the complex physical process of laser polishing, establishes a finite element simulation model, simulates the flow field velocity distribution after laser polishing, and calculates the flow field velocity through the following formula. Then, the flow field velocity is integrated with the polishing time to obtain the surface morphology of the fused silica element. The surface contour curve is then extracted and transformed into independent contour points to obtain the height information of different contour points.

[0024] The flow velocity can be calculated using the Navier-Stokes equations, taking into account the effects of surface tension and Marangoni force on the flow velocity. The formula is as follows:

[0025]

[0026] Where η(T) is the temperature-dependent dynamic viscosity coefficient, ρ represents the density of fused silica, u is the flow velocity, and P pre Let κ be the pressure, σ0 be the surface profile curvature, and σ0 be the surface tension coefficient. For temperature gradient.

[0027] The formula for calculating the surface profile is:

[0028]

[0029] Where z is the surface profile, u is the flow velocity, and t is the polishing time;

[0030] S2.3 Calculate the surface roughness values ​​of the surface after polishing at different speeds according to the following formula, obtain the fitting curve between scanning speed and surface roughness, find the scanning speed corresponding to the minimum roughness, and select the scanning speed for polishing experiment.

[0031] The surface roughness value can be calculated using the following formula:

[0032]

[0033] Where RMS is the roughness, x is the profile height, and N is the number of profile points.

[0034] The fitting curve expression for scanning speed versus surface roughness is as follows:

[0035]

[0036] Where RMS is the roughness and v is the scanning speed.

[0037] The laser polishing parameters mentioned in step S3 include: laser wavelength of 10.6μm, power of 10W-150W, scanning speed of 1mm / s-10mm / s, path spacing of 20μm-1mm, and spot diameter of 2mm-6mm.

[0038] In step S4, the thermodynamic temperature distribution is calculated using the Fourier thermodynamic equation, and the formula is:

[0039]

[0040] Where ρ represents the density of fused silica, C p The laser represents the specific heat capacity of fused silica, A is the absorptivity, R is the reflectivity, P is the laser power, w0 is the laser beam radius, and v is the specific heat capacity of fused silica. s Here, t is the scanning speed, t is the polishing time, and x is the laser position.

[0041] Using the above formula, the internal temperature distribution of the material under different laser powers was calculated. When the temperature was within the range of melting temperature (1800K) and evaporation temperature (2500K), the laser power corresponding to different component thicknesses was obtained, and the fitting curve expression between the two was as follows:

[0042]

[0043] Where P is the laser power and d is the thickness of the component.

[0044] The scanning paths described in steps S3 and S5 include raster-type scanning paths, with the start and end points of each scanning path extending beyond the processing surface.

[0045] In the laser polishing experiment of step S3, the spot radius, laser power, laser frequency, laser wavelength, and path spacing are the same as the parameters in the finite element simulation of step S2. In the laser polishing experiment of step S5, the spot radius, laser power, laser frequency, laser wavelength, and path spacing are the same as the parameters in the finite element simulation of step S4.

[0046] In steps S3 and S5, a thermometer is used to monitor the highest surface temperature of the component in real time and to control the laser scanning speed. If the surface temperature of the component is lower than the melting temperature of fused silica (1800K), the scanning speed is reduced. If the surface temperature of the component is higher than the vaporization temperature of fused silica (2500K), the scanning speed is increased.

[0047] Compared with the prior art, the technical effects of the present invention are as follows:

[0048] (1) The scanning speed and laser power in the laser polishing process of fused silica are optimized by multi-physics field coupled finite element simulation. The method is extremely simple, avoids a large number of parameter exploration experiments, and can quickly optimize the polishing parameters.

[0049] (2) By experimentally measuring the specific heat capacity coefficient, viscosity coefficient and thermal conductivity coefficient, the evolution law of the complex properties of the material with temperature was obtained, which effectively improved the accuracy of the finite element model.

[0050] (3) This invention fully utilizes the effect of laser polishing to remelt and flow the material, significantly reducing surface roughness; high-quality fused silica surfaces are obtained by laser double-sided polishing. The process of this invention is simple and low-cost, and can significantly improve the surface quality. At the same time, it eliminates the need for any chemical polishing fluids, making it environmentally friendly. This method expands the application scenarios of laser processing and is of great significance to the field of laser ultra-precision machining. Attached Figure Description

[0051] Figure 1 A flowchart of a high-precision laser double-sided polishing method for fused silica surfaces;

[0052] Figure 2 This is a schematic diagram of the laser polishing device of the present invention;

[0053] Figure 3 This is a schematic diagram of the laser double-sided polishing method of the present invention;

[0054] Figure 4 The image shows a comparison of the surface shape of a fused silica element before and after laser polishing. In the image, a is the surface shape after mechanical and chemical polishing, b is the surface shape after single-sided laser polishing, and c is the surface shape after double-sided laser polishing.

[0055] Figure 5 The roughness comparison is shown before and after laser polishing of fused silica components. In the figure, a is the roughness after mechanical and chemical polishing, b is the roughness after single-sided laser polishing, and c is the roughness after double-sided laser polishing. Detailed Implementation

[0056] The method for high-precision laser double-sided polishing of fused silica surfaces is described in detail below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the scope of protection of the present invention.

[0057] In this embodiment, the parameters are set as follows: laser wavelength is 10.6 μm, laser power is 100 W, laser frequency is 95 kHz, scanning speed is 1.3 mm / s, path spacing is 200 μm, beam radius is 4 mm, and the scanning path is a grid path. The start and end points of each scanning path extend beyond the processing surface to avoid heat accumulation at turning points. During processing, a temperature sensor is used to monitor the highest surface temperature of the component in real time, and the laser scanning speed is controlled accordingly. If the surface temperature of the component is lower than the melting temperature of fused silica (1800 K), the scanning speed is reduced; if the surface temperature of the component is higher than the vaporization temperature of fused silica (2500 K), the scanning speed is increased. The workpiece to be processed is a square fused silica planar workpiece with a side length of 30 mm and a thickness of 3 mm.

[0058] A high-precision laser double-sided polishing method for fused silica surfaces, the process flow of which is as follows: Figure 1 As shown in the figure, the method includes the following steps:

[0059] 1) Rinse the fused silica element in deionized water, then sonicate it in pure water at 20-30℃ for 10-15 minutes, rinse it with deionized water, and dry it with compressed air to obtain a clean fused silica surface.

[0060] 2) Optimize the scanning speed of the target surface. Use COMSOL software for finite element simulation to simulate the surface profile evolution and roughness of the fused silica element after CO2 laser polishing at different scanning speeds. Obtain the fitting curve of scanning speed versus surface roughness, and then determine the scanning speed with minimum roughness. The specific steps are as follows:

[0061] ① The influence of material properties on polishing effect with temperature change was considered. The specific heat capacity coefficient, viscosity coefficient and thermal conductivity coefficient of fused silica with temperature change were obtained by experimental measurement. The three coefficients were set as parameters of material properties in finite element simulation, and other parameters were consistent with experimental parameters.

[0062] The expression for the specific heat capacity coefficient of fused silica is:

[0063]

[0064] The expression for the viscosity coefficient of fused silica is:

[0065]

[0066] The expression for the thermal conductivity of fused silica is:

[0067]

[0068] ② Establish a simulation model, perform mesh generation on it with a minimum mesh size of 2nm, then set the material property parameters from ①, and then set the same polishing parameters as in the experiment. Substitute these parameters into the model settings to perform transient simulation calculations, run the software to calculate the flow field velocity, then integrate the flow field velocity with the polishing time to obtain the surface morphology of the fused silica element, then extract the surface profile curve, transform the surface profile curve into independent profile points, and obtain the height information of different profile points.

[0069] The flow velocity can be calculated using the Navier-Stokes equations, taking into account the effects of surface tension and Marangoni force on the flow velocity. The governing equation for surface tension is:

[0070]

[0071] In the formula, κ is the surface profile curvature, and σ0 is the surface tension coefficient.

[0072] The governing equation for the Marangoni force is:

[0073]

[0074] For temperature gradient.

[0075] The formula for calculating flow velocity is:

[0076]

[0077] Where η(T) is the temperature-dependent dynamic viscosity coefficient, ρ represents the density of fused silica, u is the flow velocity, and P pre Let κ be the pressure, σ0 be the surface profile curvature, and σ0 be the surface tension coefficient. For temperature gradient.

[0078] The formula for calculating the surface profile is:

[0079]

[0080] Where z is the surface profile, u is the flow velocity, and t is the polishing time.

[0081] ③ Calculate the surface roughness values ​​after polishing at different speeds according to the following formula, obtain the fitting curve between scanning speed and surface roughness, find the scanning speed corresponding to the minimum roughness, and select this scanning speed for polishing experiments.

[0082] The surface roughness value can be calculated using the following formula:

[0083]

[0084] Where RMS is the roughness, x is the profile height, and N is the number of profile points.

[0085] The fitting curve expression for scanning speed versus surface roughness is as follows:

[0086]

[0087] Where RMS is the roughness and v is the scanning speed.

[0088] 3) Place the fused silica element on the moving platform, set the laser polishing parameters and scanning path, and adjust the polishing starting point position. Process the target surface according to the scanning speed set in step 2). A schematic diagram of the laser polishing device is shown below. Figure 2 As shown;

[0089] 4) The polishing power on the back side of the target surface was optimized. Finite element simulation was used to calculate the internal thermodynamic temperature distribution of the fused silica element after CO2 laser polishing with different powers. The thermodynamic temperature distribution was calculated using the Fourier thermodynamic equation, the formula of which is:

[0090]

[0091] Where ρ represents the density of fused silica, C p represents the specific heat capacity of fused silica, and Q represents the laser heat source;

[0092] The expression for the laser heat source is:

[0093]

[0094] Where A is the absorptivity, R is the reflectivity, P is the laser power, w0 is the laser beam radius, and v s t represents the scanning speed, t represents the polishing time, and x represents the laser position.

[0095] Using the above formula, the internal temperature distribution of the material under different laser powers can be calculated. When the temperature is within the range of melting temperature (1800K) and evaporation temperature (2500K), the laser power corresponding to different component thicknesses can be obtained, and the fitting curve expression between the two is as follows:

[0096]

[0097] Where P is the laser power and d is the thickness of the component.

[0098] It is worth noting that the parameters in the laser polishing experiment are the same as those in the finite element simulation.

[0099] 5) Switch the laser processing surface to the back of the target surface, measure the component thickness, and select the laser power for polishing according to the fitting curve of component thickness and laser power in step 4). Keep other polishing parameters and scanning path consistent with step 3). A schematic diagram of laser double-sided polishing is shown below. Figure 3 As shown;

[0100] 6) Ultrasonic cleaning of fused silica elements: First rinse with deionized water, then sonicate in pure water at 20-30℃ for 10-15 minutes, rinse with deionized water again, and finally dry on a clean bench to obtain ultrasonically cleaned fused silica elements.

[0101] The surface shape of the fused silica element processed by the method of this invention was inspected using a laser interferometer (VeriFire XPZ, Zygo), and the results are as follows. Figure 4 As shown, a represents the surface finish after mechanical and chemical polishing, b represents the surface finish after single-sided laser polishing, and c represents the surface finish after double-sided laser polishing. The roughness of the fused silica element processed by the method of this invention was measured using a 4D optical profilometer (NanoCam Sq, 4D Technology). The test size was 0.5mm × 0.5mm. The results are as follows: Figure 5 As shown, a) represents the surface roughness after mechanical and chemical polishing, b) represents the surface roughness after single-sided laser polishing, and c) represents the surface roughness after double-sided laser polishing. The results show that, compared to the single-sided laser polishing method, the surface roughness (PV) and RMS of the fused silica element processed by the method of this invention decreased from 2.140λ and 0.435λ to 0.957λ and 0.194λ, respectively. The RMS value of the fused silica element roughness decreased from 1.349 nm on the initial surface to 0.270 nm after processing by the method of this invention. When processing fused silica elements, the processing method of this invention can significantly suppress surface roughness deterioration and significantly improve surface roughness. The processing results observed in the examples demonstrate the significant practical effect of this invention.

[0102] This invention employs multiphysics coupled finite element simulation to optimize the scanning speed and laser power during the laser polishing process of fused silica. The method is extremely simple, avoiding extensive parameter exploration experiments and enabling rapid optimization of polishing parameters. Furthermore, by experimentally measuring the specific heat capacity, viscosity coefficient, and thermal conductivity, the evolution of the material's complex properties with temperature was obtained, effectively improving the accuracy of the finite element model. High-quality fused silica surfaces are obtained through double-sided laser polishing. This invention features a simple and low-cost process that significantly improves surface quality and reduces roughness, while eliminating the need for any chemical polishing solutions, making it environmentally friendly. This method expands the application scenarios of laser processing and has significant implications for the field of laser ultra-precision machining.

Claims

1. A method for high-precision laser double-sided polishing of fused silica surfaces, characterized in that, The main steps include: S1 Fused Quartz Surface Pretreatment: Rinse the fused quartz element in deionized water, then sonicate it in pure water at a temperature of 20-30℃ for 10-15 minutes, rinse it with deionized water again, and finally dry it with compressed air to obtain a clean fused quartz surface. S2 target surface scanning speed optimization: The scanning speed at which CO2 laser polishing is achieved is determined by finite element simulation of the results at different scanning speeds. S3 Target Surface Machining: Place the fused silica element on the moving platform, set the laser polishing parameters and scanning path, adjust the polishing starting point position, and perform target surface machining according to the scanning speed set in step S2; S4 Target Side Back Polishing Power Optimization: The thermodynamic temperature distribution inside the fused quartz element after polishing with CO2 lasers of different powers was calculated by finite element simulation. The temperature of both the target side and the back side of the target side exceeded the melting temperature of the material (1800K) and was lower than the evaporation temperature of the material (2500K). Thus, the fitting curve of element thickness versus laser power was obtained. S5 Target Back Side Processing: Change the laser processing surface to the back side of the target surface, measure the component thickness, select the laser power for polishing according to the fitting curve of component thickness and laser power in step S4, and keep other polishing parameters and scanning path consistent with step S3. S6 fused silica element ultrasonic cleaning: First rinse with deionized water, then sonicate in pure water at 20-30℃ for 10-15 minutes, rinse with deionized water again, and finally place on a clean bench to dry, to obtain the ultrasonically cleaned fused silica element.

2. The laser double-sided polishing method for high-precision fused silica surfaces as described in claim 1, characterized in that, The specific steps of the finite element simulation described in step S2 are as follows: S2.1 Based on experimental measurements, the specific heat capacity coefficient, viscosity coefficient, and thermal conductivity coefficient of fused silica as a function of temperature are obtained, and these three coefficients are set as parameters of material properties in finite element simulation. The expression for the specific heat capacity coefficient of fused silica is: The expression for the viscosity coefficient of fused silica is: The expression for the thermal conductivity of fused silica is: S2.2 Establish a finite element simulation model to simulate the flow field velocity distribution after laser polishing, and calculate the flow field velocity using the following formula. Integrate the flow field velocity with respect to the polishing time to obtain the surface morphology of the fused silica element, then extract the surface contour curve, and transform the surface contour curve into independent contour points to obtain the height information of different contour points. The flow velocity was calculated using the Navier-Stokes equations, taking into account the effects of surface tension and Marangoni force on the flow velocity. The formula is as follows: Where η(T) is the temperature-dependent dynamic viscosity coefficient, ρ represents the density of fused silica, u is the flow velocity, and P pre Let κ be the pressure, σ0 be the surface profile curvature, and σ0 be the surface tension coefficient. For temperature gradient; The formula for calculating the surface profile is: Where z is the surface profile, u is the flow velocity, and t is the polishing time; S2.3 Calculate the surface roughness values ​​of the surface after polishing at different speeds according to the following formula, obtain the fitting curve between scanning speed and surface roughness, find the scanning speed corresponding to the minimum roughness, and select the scanning speed for polishing experiment. The formula for calculating surface roughness is as follows: Where RMS is the roughness, x is the profile height, and N is the number of profile points; The fitting curve expression for scanning speed versus surface roughness is as follows: Where RMS is the roughness and v is the scanning speed.

3. The laser double-sided polishing method for high-precision fused silica surfaces as described in claim 1, characterized in that, The laser polishing parameters mentioned in step S3 include: laser wavelength of 10.6μm, power of 10W-150W, scanning speed of 1mm / s-10mm / s, path spacing of 20μm-1mm, and spot diameter of 2mm-6mm.

4. The method for high-precision laser double-sided polishing of fused silica surfaces as described in claim 1, characterized in that, The scanning paths described in steps S3 and S5 include raster-type scanning paths, with the start and end points of each scanning path extending beyond the processing surface.

5. The laser double-sided polishing method for high-precision fused silica surfaces as described in claim 1, characterized in that, In step S4, the thermodynamic temperature distribution is calculated using the Fourier thermodynamic equation, as shown in the following formula: Where ρ represents the density of fused silica, C p The laser represents the specific heat capacity of fused silica, A is the absorptivity, R is the reflectivity, P is the laser power, w0 is the laser beam radius, and v is the specific heat capacity of fused silica. s Here, t is the scanning speed, t is the polishing time, and x is the laser position. The internal temperature distribution of the material under different laser powers was calculated using the above formula. When the temperature was within the range of melting temperature and evaporation temperature (melting temperature = 1800K, evaporation temperature = 2500K), the laser power corresponding to different component thicknesses was obtained, and the fitting curve expression between the two was: Where P is the laser power and d is the thickness of the component.

6. The method for high-precision laser double-sided polishing of fused silica surfaces as described in claim 1, characterized in that, In the laser polishing experiment of step S3, the spot radius, laser power, laser frequency, laser wavelength, and path spacing are the same as the parameters in the finite element simulation of step S2. In the laser polishing experiment of step S5, the spot radius, laser power, laser frequency, laser wavelength, and path spacing are the same as the parameters in the finite element simulation of step S4.

7. The laser double-sided polishing method for high-precision fused silica surfaces as described in claim 1, characterized in that, In steps S3 and S5, a thermometer is used to monitor the highest surface temperature of the component in real time and to control the laser scanning speed. If the surface temperature of the component is lower than the melting temperature of fused silica (1800K), the scanning speed is reduced. If the surface temperature of the component is higher than the evaporation temperature of fused silica (2500K), the scanning speed is increased.

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