A method and device for machining film cooling holes of a blade with a thermal barrier coating

Abstract

The present invention provides a method and device for machining film cooling holes on a blade with a thermal barrier coating. The machining method includes the following steps: S1. Fix the blade with the thermal barrier coating, and use femtosecond laser to remove the thermal barrier coating at the hole punching position to expose the surface of the blade body. The incident angle of the femtosecond laser is α, where 30° ≥ α ≥ 15°; S2. Use millisecond laser to perform direct punching at the hole punching position to form a blind hole on the blade body. The incident angle of the millisecond laser is β, where 20° ≥ β - α ≥ 5°; S3. Adopt mechanical drilling to drill through the bottom hole to form a through hole; S4. Use electro-hydraulic beam to trim the hole wall to machine the film cooling holes. The present invention adopts a process combining double-laser machining, mechanical drilling, and electro-hydraulic beam hole trimming, effectively improving the machining efficiency and quality of the film cooling holes, ensuring that the machined film cooling holes meet the requirements in terms of dimensional accuracy, surface quality, etc., and can efficiently obtain high-quality film cooling holes.

Description

Technical Field

[0001] The present invention relates to the technical field of blade film hole machining, and more particularly, to a method and device for machining film holes of a blade with a thermal barrier coating. Background Art

[0002] With the continuous development of advanced aero-engines, the gas temperature before the turbine gradually increases, posing higher requirements for the temperature-bearing capacity of turbine blades. To meet the requirements of hot-end components such as turbine blades in extreme service environments with high temperature, high pressure, and high rotational speed, the aero-engine field has been using thermal barrier coating technology and film hole cooling technology to reduce the service temperature of hot-end components, thereby extending their service life.

[0003] The thermal barrier coating is generally a double-layer structure, namely the ceramic layer on the surface and the bonding layer on the inner layer, and its main functions are heat insulation and oxidation resistance. Traditional film hole machining methods such as electrical discharge machining cannot machine thermal barrier coatings with poor conductivity, and the prior coating after hole-making scheme inevitably has problems such as shrinkage holes and blocked holes, with poor design compliance. To directly drill holes in the thermal barrier coating, the prior art proposes to use laser machining methods. For example, patent document CN201410213528.7 discloses a process for preparing film cooling holes based on picosecond laser-assisted machining, and patent document CN201711450432.2 discloses a method and device for machining film holes of a blade with a thermal barrier coating using femtosecond laser, but these machining technologies have problems such as low machining efficiency and poor film hole quality. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to develop a technology for machining film holes of a blade with a thermal barrier coating to improve machining efficiency and quality.

[0005] To achieve the above purpose, the first aspect of the present invention provides a method for machining film holes of a blade with a thermal barrier coating, including the following steps:

[0006] S1. Fix the blade with a thermal barrier coating, and use a femtosecond laser to remove the thermal barrier coating at the hole-making position to expose the surface of the blade body. The incident angle of the femtosecond laser is α, and 30° ≥ α ≥ 15°;

[0007] S2. Use a millisecond laser to perform direct punching at the hole-making position to form a blind hole on the blade body. The incident angle of the millisecond laser is β, and 20° ≥ β - α ≥ 5°;

[0008] S3. Use mechanical drilling to punch through the bottom hole to form a through hole;

[0009] S4. Use electro-hydraulic beam to trim the hole wall of the film hole to obtain the film hole.

[0010] The present invention adopts a process combining double laser processing, mechanical drilling, and electro-hydraulic beam hole finishing. First, a femtosecond laser is used to remove the thermal barrier coating at the drilling site. Utilizing its ultrashort pulse and high-precision characteristics, it can accurately remove the coating with little damage to the blade body. Combined with a millisecond laser direct punching method, a blind hole is quickly formed. Then, a through hole is formed by mechanical drilling, making the hole wall basically flat. Finally, the electro-hydraulic beam is used to precisely finish the hole wall, forming a complete processing flow, effectively improving the efficiency and quality of air film hole processing, ensuring that the processed air film holes meet the requirements in terms of dimensional accuracy, surface quality, etc., and enabling high-quality air film holes to be obtained efficiently.

[0011] Furthermore, the present invention differentiates the incident angles of the femtosecond laser and the millisecond laser. The obliquely incident femtosecond laser increases the contact area between the laser and the coating, improves the photon energy absorption rate, and accelerates the peeling of the thermal barrier coating. It is limited that 30°≥α≥15°, ensuring that the laser energy is concentrated on the surface layer of the coating and avoiding deep penetration damage to the blade body. The millisecond laser has a certain angular difference from the femtosecond laser, preventing the millisecond laser from accidentally ablating the exposed blade body edge area during processing, reducing the burrs at the air film hole opening and the thickness of the heat-affected zone. The angular difference guides the molten matter of the millisecond laser to be discharged along the outer side of the hole wall, inhibiting the formation of a recast layer and reducing the subsequent workload of hole wall finishing.

[0012] In a preferred or alternative solution, in the step S1, the thickness of the thermal barrier coating is less than or equal to 0.5 mm, the pulse width of the femtosecond laser is less than 1 ps, the single-pulse energy is 20~1000 μJ, the scanning speed is 0.1~3 m / s, and the processing time is less than or equal to 10 s. Limiting the femtosecond laser parameters according to the thickness of the thermal barrier coating makes the process of removing the thermal barrier coating by the femtosecond laser more precise, efficient, and controllable, achieving rapid removal of the thermal barrier coating and avoiding excessive thermal influence while ensuring the removal effect.

[0013] In a preferred or alternative solution, in the step S1, the scanning speed of the femtosecond laser is adjusted according to the curvature of the blade surface, V = 0.1 + 0.05×(1 / R), where V is the scanning speed of the femtosecond laser in m / s and R is the local curvature radius of the blade in mm. The scanning speed of the femtosecond laser is dynamically adjusted according to the curvature of the blade surface, enabling the process of laser removing the thermal barrier coating to better fit the complex curved surface shape of the blade, ensuring that processing can be carried out at an appropriate speed at different curvature positions, thereby improving the quality and accuracy of coating removal, avoiding incomplete coating removal or damage to the blade body caused by inappropriate speed, and further enhancing the adaptability and reliability of the processing.

[0014] In a preferred or alternative embodiment, in step S2, the pulse width of the millisecond laser used is greater than or equal to 1 ms, the single-pulse energy is greater than or equal to 1 J, and the processing time is less than or equal to 1 s. The present invention uses a millisecond laser direct punching method. The larger pulse width and single-pulse energy can provide sufficient energy density, making the punching process more efficient. By controlling the processing time within 1 s, the formation of the film cooling holes can be completed quickly, and the depth-to-diameter ratio and diameter of the obtained film cooling holes meet specific requirements, ensuring the performance and cooling effect of the film cooling holes.

[0015] In a preferred or alternative embodiment, in step S2, the depth-to-diameter ratio of the blind hole obtained is greater than or equal to 20, and the diameter is greater than or equal to 0.3 mm. The larger depth-to-diameter ratio and diameter are beneficial to the flow of the cooling medium, improving the cooling efficiency, meeting the cooling requirements of the blade during actual operation, and ensuring the reliability and service life of the blade in a high-temperature environment.

[0016] In a preferred or alternative embodiment, in step S4, the electro-hydraulic beam machining voltage is 12 - 300 V, and the processing time is less than or equal to 10 s. The appropriate machining voltage can ensure the trimming effect of the electro-hydraulic beam on the hole wall and improve the surface quality of the film cooling holes.

[0017] In a preferred or alternative embodiment, in step S3, Al2O3 abrasive with a size of 20 - 50 nm is added to the electrolyte used for electro-hydraulic beam machining. Adding Al2O3 abrasive to the electrolyte enhances the polishing effect, further improves the surface quality of the hole wall, reduces the hole wall roughness, and improves the cooling effect and overall performance of the blade.

[0018] In a preferred or alternative embodiment, for the mass a of the blade body material removed in step S2, and the total mass b of the blade body material removed in steps S3 and S4, a / b > 9. Removing more than 90% of the material quickly using a millisecond laser is beneficial for shortening the time required for the electro-hydraulic beam machining step and improving the overall machining efficiency.

[0019] The second aspect of the present invention provides a device for implementing the above-mentioned method for machining film cooling holes of a blade with a thermal barrier coating, including:

[0020] A five-axis system, including three linear axis drive modules and two rotary axis drive modules. The three linear axis drive modules are respectively an X-axis drive module, a Y-axis drive module, and a Z-axis drive module, and the two rotary axis drive modules are respectively an A-axis drive module and a C-axis drive module;

[0021] A stage for fixing the blade to be machined, and the A-axis drive module and the C-axis drive module are drivingly connected to the stage;

[0022] Processing component, the processing component includes a femtosecond laser processing head, a millisecond laser processing head, a drill bit and a rotatable electro - hydraulic beam processing head, and the X - axis drive module, the Y - axis drive module and the Z - axis drive module are used to drive the processing component to perform linear movement;

[0023] Dynamic focusing system, used to scan the curvature of the blade surface in real time;

[0024] Control system, the control system is electrically connected to the five - axis system, the dynamic focusing system and the processing component. The dynamic focusing system is used to input the surface curvature data into the control system, and the control system is used to control the movement of the five - axis system, adjust the angles of the stage and the processing component, and control the process parameters of the processing component.

[0025] The processing device of the present invention realizes multi - angle and multi - azimuth processing through the five - axis system, and can flexibly adapt to the complex shapes of the blades and the processing requirements of different parts; the processing component integrates a femtosecond laser, a millisecond laser, an electro - hydraulic beam processing head and a drill bit, and the entire processing process can be completed on one device, improving the processing efficiency and accuracy; the dynamic focusing system scans the curvature of the blade surface in real time, providing accurate data support for the control system, enabling the control system to precisely control the actions of the five - axis system and the processing component, realizing precise regulation of the processing process, thereby ensuring the stable and reliable quality of the processed film holes, meeting the design requirements, and improving the automation degree and controllability of the entire processing technology.

[0026] In a preferred or alternative solution, it further includes a mounting bracket. The femtosecond laser processing head, the millisecond laser processing head, the drill bit and the electro - hydraulic beam processing head are arranged on the mounting bracket, and the X - axis drive module, the Y - axis drive module and the Z - axis drive module are all drivingly connected to the mounting bracket. The mounting bracket integrally arranges the femtosecond laser processing head, the millisecond laser processing head, the drill bit and the electro - hydraulic beam processing head, facilitating the collaborative operation and switching between the processing heads. At the same time, the X, Y, and Z - axis drive modules are drivingly connected to the mounting bracket, which can accurately control the position and movement trajectory of the processing component in space, further improving the processing accuracy and flexibility, ensuring that each processing step can be accurately carried out at the corresponding part of the blade, guaranteeing the processing quality and efficiency, and also facilitating the overall structural layout and operation and maintenance of the device.

[0027] In a preferred or alternative embodiment, it further includes a first lifting mechanism and a second lifting mechanism disposed on the mounting bracket. The first lifting mechanism is drivingly connected to the picosecond laser processing head, and the second lifting mechanism is drivingly connected to the drill bit. The two lifting mechanisms can achieve precise adjustment of the picosecond laser processing head and the drill bit in the vertical direction, enabling the picosecond laser and the drill bit to better align with the punching positions at different heights of the blade, adapting to the three-dimensional curved surface shape of the blade, and ensuring the accuracy and quality of direct punching.

[0028] In summary, through the collaborative optimization of multiple processes, the present invention has overcome the industry problem of difficult to balance quality and efficiency in the processing of film cooling holes on blades with thermal barrier coatings, and provides a reliable solution for the manufacturing of high-performance blades for aeroengines and gas turbines. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of the blade after femtosecond laser processing in an embodiment of the present invention.

[0030] Figure 2 It is a schematic structural diagram of the blade after picosecond laser processing in a specific embodiment of the present invention.

[0031] Figure 3 It is a schematic structural diagram of the blade after electro-hydraulic beam processing in a specific embodiment of the present invention.

[0032] Figure 4 It is an overall structure diagram of the film cooling hole processing device in Embodiment 1 of the present invention.

[0033] Figure 5 It is an assembly structure diagram of the processing component in Embodiment 1 of the present invention.

[0034] Figure 6 It is a sectional view of the film cooling hole obtained after picosecond laser processing in Embodiment 2 of the present invention.

[0035] Figure 7 It is an SEM image of the film cooling hole obtained after picosecond laser processing in Embodiment 2 of the present invention.

[0036] Figure 8 It is a pore wall morphology diagram of the film cooling hole after electro-hydraulic beam trimming in Embodiment 2 of the present invention.

[0037] Explanation of reference numerals:

[0038] 1. Frame; 21. X-axis drive module; 22. Y-axis drive module; 23. Z-axis drive module; 24. A-axis drive module; 25. C-axis drive module; 3. Carrier table; 41. Femtosecond laser processing head; 42. Millisecond laser processing head; 43. Drill bit; 44. Electro-hydraulic beam processing head; 5. Mounting bracket; 51. First lifting mechanism; 52. Second lifting mechanism; 6. Dynamic focusing system; 7. Control system; 81. Thermal barrier coating; 82. Blade body; 83. Film cooling hole. Detailed implementation manners

[0039] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and illustrated herein generally may be arranged and designed in a variety of different configurations.

[0040] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not require further definition and explanation in subsequent drawings.

[0041] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0042] The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0043] The detailed implementation manners of the present invention provide a method for processing film cooling holes of a blade with a thermal barrier coating, including the following steps:

[0044] S1. Fix the blade with the thermal barrier coating 81, and use a femtosecond laser to remove the thermal barrier coating 81 at the drilling position at an incident angle of α, exposing the surface of the blade body 82. The structure of the blade after this step of processing is as Figure 1 shown.

[0045] In a specific embodiment, the incident angle α of the femtosecond laser is between 15° and 30°. The obliquely incident femtosecond laser can ensure that the laser energy is concentrated on the thermal barrier coating 81, so that the thermal barrier coating 81 can be quickly peeled off while avoiding damage to the blade body 82.

[0046] In a specific embodiment, the thickness of the thermal barrier coating 81 is less than or equal to 0.5 mm, the pulse width of the femtosecond laser is less than 1 ps, the single-pulse energy is 20 - 1000 μJ, the scanning speed is 0.1 - 3 m / s, and the processing time is less than or equal to 10 s. Limiting the femtosecond laser parameters according to the thickness of the thermal barrier coating 81 makes the process of removing the thermal barrier coating 81 by the femtosecond laser more precise, efficient, and controllable. Further, the scanning speed of the femtosecond laser is adjusted according to the surface curvature of the blade, so that the process of removing the thermal barrier coating 81 by the laser can better fit the complex surface shape of the blade, ensuring that the processing can be carried out at an appropriate speed at different curvature positions, thereby improving the quality and accuracy of removing the thermal barrier coating 81. The specific calculation formula is V = 0.1 + 0.05×(1 / R), where V is the scanning speed of the femtosecond laser, the unit is m / s, and R is the local curvature radius of the blade, the unit is mm.

[0047] S2. Use a millisecond laser to perform direct punching at the punching site. The incident angle of the millisecond laser is β, and a blind hole is formed on the blade body 82. The structure of the blade after this step of processing is as Figure 2 shown.

[0048] In a specific embodiment, the pulse width of the used millisecond laser is greater than or equal to 1 ms, the single-pulse energy is greater than or equal to 1 J, the processing time is less than or equal to 1 s, and the depth-to-diameter ratio of the obtained blind hole is greater than or equal to 20, and the diameter is greater than or equal to 0.3 mm. Using the millisecond laser for direct punching, the larger pulse width and single-pulse energy can provide sufficient energy density, making the punching process more efficient and quickly completing the formation of the blind hole, and the depth-to-diameter ratio and diameter of the obtained blind hole meet the cooling requirements of the blade during actual operation.

[0049] Further, the incident angle β of the millisecond laser and the incident angle α of the femtosecond laser are designed differently, satisfying 20°≥β - α≥5°. Correspondingly, the processing area of the millisecond laser should be slightly smaller than the peeling area of the thermal barrier coating 81 to avoid interference. The differential design of the incident angle of the millisecond laser can prevent the millisecond laser from accidentally ablating the exposed edge area of the blade body 82 during processing, reduce the burrs at the hole opening and the thickness of the heat-affected zone, and the angle difference guides the molten material of the millisecond laser to be discharged along the outer side of the hole wall, inhibiting the formation of the recast layer and reducing the subsequent workload of hole trimming.

[0050] S3. Use a mechanical drilling method to drill through the bottom hole to form a through hole. In this step, a through hole is formed by the mechanical drilling method, and the hole wall is basically flat, improving the surface quality of the hole wall.

[0051] S4. Use an electro-hydrodynamic beam to trim the hole wall. The structure of the blade after this step of processing is as Figure 3 shown, and a film cooling hole 83 is processed. In a specific embodiment, the electro-hydrodynamic beam processing voltage is 12 - 300 V, and the processing time is less than or equal to 10 s.

[0052] In a specific embodiment, the mass of the blade body material removed in step S2 is a, and the total mass of the blade body material removed in step S3 and step S4 is b, satisfying a / b > 9, that is, using a millisecond laser to quickly remove more than 90% of the material, which is beneficial to shortening the time required for the electro-hydraulic beam machining step and improving the overall machining efficiency.

[0053] Furthermore, 20 - 50 nm of Al2O3 abrasive is added to the electrolyte used in electro-hydraulic beam machining, which can enhance the polishing effect, improve the surface quality of the hole wall, reduce the hole wall roughness, and enhance the cooling effect and overall performance of the blade.

[0054] The above method adopts a dual-laser machining combined with an electro-hydraulic beam hole-making process. First, a femtosecond laser is used to remove the non-conductive thermal barrier coating 81, then a millisecond laser is used to quickly form a blind hole, and then a through hole is formed by mechanical drilling, and the hole wall is made basically flat. Finally, a rotatable electro-hydraulic beam flow is used to finely machine the hole wall, and a high-quality film hole 83 can be efficiently obtained.

[0055] Example 1

[0056] Combined Figure 4 and Figure 5 As shown, this embodiment provides a processing device for film holes of a blade with a thermal barrier coating, which is used to implement the above processing method. The device includes a control system 7, a frame 1, and components such as a five-axis system, a stage 3, a processing component, and a dynamic focusing system 6 arranged on the frame 1. The five-axis system includes three linear axis drive modules and two rotary axis drive modules. The three linear axis drive modules are an X-axis drive module 21, a Y-axis drive module 22, and a Z-axis drive module 23 respectively. The two rotary axis drive modules are an A-axis drive module 24 and a C-axis drive module 25 respectively. The processing component includes four processing heads, namely a femtosecond laser processing head 41, a millisecond laser processing head 42, a drill bit 43, and a rotatable electro-hydraulic beam processing head 44. The X-axis drive module 21, the Y-axis drive module 22, and the Z-axis drive module 23 are used to drive the processing component to move linearly. The stage 3 is arranged on the frame 1 and is used to fix the blade to be processed. The A-axis drive module 24 and the C-axis drive module 25 are drivingly connected to the stage 3 and can drive the stage 3 to rotate bidirectionally. The processing device controls the relative positions and angles of each processing head and the blade to be processed through the five-axis drive module. The dynamic focusing system 6 is used to scan the curvature of the blade surface in real time, including a surface profile scanner and an adaptive zoom lens group. The control system 7 is used to control the operation of the device, and it is electrically connected to the five-axis system, the dynamic focusing system 6, and the processing component.

[0057] During the machining process, the dynamic focusing system 6 inputs the surface curvature data of the blade into the control system 7. The control system 7 controls the movement of the five-axis system, discretizes the tool path into tiny line segments using interpolation algorithms, calculates the movement of each axis segment by segment, and adjusts the angles of the stage 3 and the machining components. After the machining head moves to the appropriate position, the control system 7 controls the process parameters of the machining head, ensuring precise regulation of the entire machining process.

[0058] In this embodiment, an installation bracket 5 is provided on the frame 1. The femtosecond laser machining head 41, the millisecond laser machining head 42, the drill bit 43, and the electro-hydraulic beam machining head 44 are arranged on the installation bracket 5. The X-axis drive module 21, the Y-axis drive module 22, and the Z-axis drive module 23 are all drivingly connected to the installation bracket 5 and can drive multiple machining heads to move synchronously in the X-axis, Y-axis, and Z-axis directions. The installation bracket 5 is also provided with a first lifting mechanism 51 and a second lifting mechanism 52. The first lifting mechanism 51 is drivingly connected to the millisecond laser machining head 42, and the second lifting mechanism 52 is drivingly connected to the drill bit 43. Thus, the vertical positions of the millisecond laser machining head 42 and the drill bit 43 can be precisely adjusted, accurately aligning the punching position and ensuring the quality and accuracy of direct punching and drilling.

[0059] The above machining device integrates femtosecond laser, millisecond laser, electro-hydraulic beam, and mechanical machining in one device, realizing laser, mechanical, and electro-hydraulic beam composite machining of film cooling holes on blades with thermal barrier coatings through one device. It has high machining efficiency, is suitable for machining common conductive blade materials such as metal materials, has good material applicability, and the obtained film cooling holes have good quality.

[0060] Embodiment 2

[0061] This embodiment uses the machining device provided in Embodiment 1 for hole making, and the specific steps are as follows:

[0062] (1) Fix the blade with a thermal barrier coating on the stage. The thickness of the thermal barrier coating is 0.4 mm, and the blade body is made of metal material.

[0063] (2) Align the femtosecond laser machining head with the punching position. The incident angle α is 20°, the single-pulse energy is 100 μJ, the scanning speed is adjusted according to the surface curvature of the blade, and the calculation formula is V = 0.1 + 0.05×(1 / R). The machining time is 8 s, and the thermal barrier coating at the punching position is removed, exposing the surface of the blade body.

[0064] (3) Align the millisecond laser machining head with the punching position, and use a millisecond laser with a single-pulse energy of 2 J to perform direct punching at the punching position. The incident angle β is 30°, and the machining time is 0.5 s, forming a blind hole with a diameter of 0.7 mm and a depth of 5 mm. The morphology of the film cooling hole obtained by the millisecond laser machining is as shown in Figure 6 and Figure 7 shown, and it has cracks, recast layers, and heat-affected zones.

[0065] (4) Align the drill bit with the blind hole and use mechanical drilling to penetrate the bottom hole to form a through hole, and make the hole wall basically flat.

[0066] (5) Align the electro-hydrodynamic beam machining head with the through hole and use electro-hydrodynamic beam to trim the hole wall. The machining voltage is 50V, the feed rate is 0.1mm / s, and the machining time is 8s. The morphology of the film cooling hole obtained by machining is as Figure 8 shown. The film cooling hole has no cracks, no recast layer, and no heat affected zone.

[0067] In this embodiment, the composite hole-making process can directly make holes on the blade with a thermal barrier coating, without the need to use the processing method of making holes first and then coating. The single-hole processing time is controlled within 20 seconds, which is significantly shorter than the time required for processing a single hole by using femtosecond laser alone. Moreover, the obtained film cooling hole has no cracks, no recast layer, and no heat affected zone, improving the quality of the film cooling hole.

[0068] Example 3

[0069] In this embodiment, the processing device provided in Example 1 is used to make holes, and the specific steps are as follows:

[0070] (1) Fix the blade with a thermal barrier coating on the stage. The thickness of the thermal barrier coating is 0.3mm, and the blade body is made of carbon fiber material.

[0071] (2) Align the femtosecond laser machining head with the hole-making position. The incident angle α is 30°, the single pulse energy is 200μJ, the scanning speed is 0.5m / s, and the machining time is 6s. The thermal barrier coating at the hole-making position is removed, exposing the surface of the blade body.

[0072] (3) Align the millisecond laser machining head with the hole-making position and use the millisecond laser with a single pulse energy of 2J to perform direct punching at the hole-making position. The incident angle β is 45°, and the machining time is 1s to form a blind hole with a diameter of 1mm and a depth of 6mm.

[0073] (4) Align the drill bit with the blind hole and use mechanical drilling to penetrate the bottom hole to form a through hole, and make the hole wall basically flat.

[0074] (5) Align the electro-hydrodynamic beam machining head with the through hole and use electro-hydrodynamic beam to trim the hole wall. The machining voltage is 100V, the feed rate is 0.05mm / s, and the machining time is 9s. The film cooling hole obtained in this embodiment has no cracks, no recast layer, and no heat affected zone.

[0075] Embodiments of the present invention provide a complete set of methods and devices for machining film holes on blades with thermal barrier coatings, effectively solving problems such as low efficiency and poor quality existing in traditional machining technologies. In terms of the machining method, by leveraging the respective advantages of femtosecond lasers, millisecond lasers, mechanical machining, and electro-hydraulic beams, combined with precise parameter control and step connection, high-precision and high-quality machining of blade film holes is achieved, improving the machining efficiency, ensuring the dimensional accuracy, surface quality, and cooling performance of the film holes, and meeting the strict requirements of high-temperature components such as aeroengines for blade performance. In terms of the device, the coordinated operation of the five-axis system, dynamic focusing system, and control system, etc., realizes the automation, intelligence, and high-precision of the machining process, further enhancing the stability of machining efficiency and quality, reducing the difficulty and error of manual operation, having significant economic and social benefits, and playing an important role in promoting the development of aeroengine blade manufacturing technology.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for machining film cooling holes of a blade with a thermal barrier coating, characterized in that, It includes the following steps: S1. Fix the blade with a thermal barrier coating, and use femtosecond laser to remove the thermal barrier coating at the drilling site to expose the surface of the blade body. The incident angle of the femtosecond laser is α, where 30° ≥ α ≥ 15°. The thickness of the thermal barrier coating is less than or equal to 0.5 mm. The pulse width of the femtosecond laser is less than 1 ps, the single pulse energy is 20 - 1000 μJ, the scanning speed is 0.1 - 3 m / s, and the processing time is less than or equal to 10 s. S2. Use millisecond laser to perform direct punching at the drilling site to form a blind hole on the blade body. The incident angle of the millisecond laser is β, where 20° ≥ β - α ≥ 5°. The pulse width of the millisecond laser is greater than or equal to 1 ms, the single pulse energy is greater than or equal to 1 J, and the processing time is less than or equal to 1 s. S3. Adopt mechanical drilling to punch through the bottom hole to form a through hole. S4. Use electro - hydraulic beam to trim the hole wall to obtain a film cooling hole.

2. The method for machining the film cooling holes of the blade with a thermal barrier coating according to claim 1, wherein In the step S1, the scanning speed of the femtosecond laser is adjusted according to the surface curvature of the blade, V = 0.1 + 0.05×(1 / R), where V is the scanning speed of the femtosecond laser in m / s, and R is the local curvature radius of the blade in mm.

3. The method for machining the air film holes of the blade with a thermal barrier coating according to claim 1, characterized in that In the step S2, the depth - diameter ratio of the obtained blind hole is greater than or equal to 20, and the diameter is greater than or equal to 0.3 mm.

4. The method for machining the air film holes of the blade with a thermal barrier coating according to claim 1, wherein, In the step S4, the electro - hydraulic beam processing voltage is 12 - 300 V, and the processing time is less than or equal to 10 s.

5. The method for machining the film cooling holes of the blade with a thermal barrier coating according to claim 4, wherein In the step S4, 20 - 50 nm of Al2O3 abrasive is added to the electrolyte used for electro - hydraulic beam processing.

6. The method for machining the film cooling holes of the blade with a thermal barrier coating according to claim 1, characterized in that, The mass of the blade body material removed in the step S2 is a, and the total mass of the blade body material removed in the steps S3 and S4 is b, satisfying a / b > 9.

7. An apparatus for implementing the method for machining the film cooling holes of the blade with a thermal barrier coating as described in any one of claims 1-6, characterized in that, It includes: A five - axis system, including three linear axis drive modules and two rotary axis drive modules. The three linear axis drive modules are the X - axis drive module (21), the Y - axis drive module (22), and the Z - axis drive module (23) respectively. The two rotary axis drive modules are the A - axis drive module (24) and the C - axis drive module (25) respectively. A stage (3) for fixing the blade to be processed. The A - axis drive module (24) and the C - axis drive module (25) are drivingly connected to the stage (3). A processing assembly. The processing assembly includes a femtosecond laser processing head (41), a millisecond laser processing head (42), a drill bit (43), and a rotatable electro - hydraulic beam processing head (44). The X - axis drive module (21), the Y - axis drive module (22), and the Z - axis drive module (23) are used to drive the processing assembly to move linearly. A dynamic focusing system (6) for scanning the surface curvature of the blade in real - time. A control system (7). The control system (7) is electrically connected to the five - axis system, the dynamic focusing system (6), and the processing assembly. The dynamic focusing system (6) is used to input the surface curvature data into the control system (7). The control system (7) is used to control the movement of the five - axis system, adjust the angles of the stage (3) and the processing assembly, and control the process parameters of the processing assembly.

8. The device according to claim 7, wherein It further includes a mounting bracket (5). The femtosecond laser processing head (41), the millisecond laser processing head (42), the drill bit (43) and the electro-hydraulic beam processing head (44) are arranged on the mounting bracket (5). The X-axis drive module (21), the Y-axis drive module (22) and the Z-axis drive module (23) are all drivingly connected to the mounting bracket (5).

9. The device according to claim 8, characterized in that, It further includes a first lifting mechanism (51) and a second lifting mechanism (52) arranged on the mounting bracket (5). The first lifting mechanism (51) is drivingly connected to the millisecond laser processing head (42), and the second lifting mechanism (52) is drivingly connected to the drill bit (43).

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