Aircraft oil filter support laser powder bed fusion rapid repair method

Abstract

The application discloses a kind of aircraft oil filter support laser powder bed fusion rapid repair method, belong to the field of aviation equipment maintenance technology, comprising the following steps: damage site cutting;Cutting surface polishing;Cutting surface cleaning;Damage cutting part model reconstruction;Damage part positioning;Repair powder processing;Repair cabin preparation;Repair;Finish machining.The application replaces repair aluminum alloy oil filter support by welding with laser powder bed fusion technology, Al-Mg-Sc-Zr aluminum alloy powder is repair material, can realize the rapid repair of oil filter support, overcome the shortcomings of traditional aluminum alloy repair welding deformation, many weld defects, poor quality;Laser powder bed fusion repair technology is used to repair the oil filter surface crack, and the performance of the oil filter support meets the technical index requirements, and the repair fusion interface is defect-free;Compared with traditional mechanical processing new piece cycle, the laser powder bed fusion repair technology is used to repair the oil filter surface crack, and the cycle is greatly shortened.

Description

Technical Field

[0001] This invention relates to the field of aviation equipment repair and molding technology, and more specifically to a method for rapid repair of aircraft oil filter brackets using laser powder bed melting. Background Technology

[0002] The aluminum alloy oil filter bracket is installed inside the aircraft air intake and is mainly used for the fixed installation of the hydraulic oil filter. The specific structure is as follows: Figure 1 As shown, its dimensions are approximately 88mm × 60mm × 55mm. Figure 1 The round hole end face connects to the machine body support, and the four assembly holes are fixed with bolts; the other end face has four pillars connected by threads for the installation of hydraulic oil filters.

[0003] During aircraft service, aluminum alloy oil filter brackets often develop multiple cracks on the round hole end face. The oil filter bracket material is 2D70, with a tensile strength ≥390MPa and elongation ≥6% in the heat-treated state. There are two existing repair methods: one is to weld the cracked area; the other is to remanufacture it using machining. Welding aluminum alloys is prone to severe deformation after welding, and defects such as porosity, slag inclusions, and incomplete penetration can easily form in the weld metal, leading to cracks and affecting product quality and performance. Machining, due to the inherent thermal conductivity and plasticity of aluminum alloys, is prone to wear, burrs, deformation, and cracking during processing. Furthermore, the part's complex structure relies heavily on tooling, resulting in a long replacement cycle and hindering repair efficiency.

[0004] Therefore, how to develop a rapid repair method for aircraft oil filter brackets using laser powder bed melting is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method for rapid repair of aircraft oil filter brackets by laser powder bed melting.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for rapid repair of aircraft oil filter brackets using laser powder bed melting includes the following steps:

[0008] (1) Cutting the damaged area: Cut off the entire end face of the aircraft oil filter bracket with cracks to obtain a horizontal cut surface;

[0009] (2) Grinding the cut surface: Grind the cut surface until it is smooth;

[0010] (3) Cleaning the cut surface: Wipe the cut surface with alcohol or acetone to remove surface oil and dirt;

[0011] (4) Model reconstruction of the damaged and cut parts: The three-dimensional model of the damaged and cut parts is reconstructed using a reverse scanner and the model is converted into STL format;

[0012] (5) Location of damaged parts: The position of damaged parts and the reference surface are measured using a coordinate measuring machine;

[0013] (6) Powder treatment for repair: Vacuum drying of metal powder;

[0014] (7) Preparation of the repair chamber of the laser powder bed fusion 3D printer: The repair chamber is cleaned with alcohol or acetone, the substrate material is aluminum alloy, the protective atmosphere is high-purity argon, and the substrate is preheated at the same time.

[0015] (8) Repair process:

[0016] ① Fix the aircraft oil filter bracket to be repaired onto the positioning fixture. The positioning fixture is fixed to the aluminum alloy base plate with bolts, and measure the coordinate points of the positioning fixture on the base plate.

[0017] ② Set the repair parameters;

[0018] ③ Apply powder to the area to be repaired using a rubber scraper. After the first application of powder, the cut end face of the area to be repaired is evenly covered with a thin layer of powder. The powder does not clump or agglomerate.

[0019] ④ Import the STL format 3D model reconstructed in step (4) into the data processing software, and place the model on the software-simulated substrate according to the coordinate points recorded in step ①. Then perform slice path planning to generate the damage area repair scanning path.

[0020] ⑤ Repair begins once the environment of the chamber to be repaired reaches the set value. The first scan involves three laser remelting steps to ensure that the repaired end face is fully melted and well bonded with the reconstructed damage area. Subsequent laser scans only need to be performed once per layer.

[0021] ⑥ Repeatedly scan along the set scanning path until the damaged area is processed;

[0022] ⑦ Once the environment in the repair chamber has returned to room temperature, open the repair chamber and remove the repair parts;

[0023] (9) Finishing: Finishing the damaged parts of the parts.

[0024] Furthermore, in step (2), the surface is ground until the flatness is ≤0.05mm.

[0025] Furthermore, in step (6), the metal powder comprises the following components by mass percentage: Mg 4%–9%, ​​Sc 0.5%–0.8%, Zr 0.2%–0.5%, Mn ≤ 0.8%, Si ≤ 1.0%, Fe ≤ 0.4%, Zn ≤ 0.25%, O ≤ 0.05%, N ≤ 0.05%, with the balance being Al. The particle size of the metal powder is 20–63 μm, and it is nearly spherical.

[0026] Furthermore, in step (6), the temperature of the vacuum drying is 80-100℃, the time of vacuum drying is 4-8h, and the Hall flow rate of the metal powder after vacuum drying is <50s / 50g.

[0027] Furthermore, in step (7), the protective mirror of the galvanometer and the rubber strip of the scraper in the repair chamber are cleaned with alcohol or acetone.

[0028] Furthermore, in step (7), the substrate material is selected as an aluminum alloy with a parallelism of ≤50μm; the protective atmosphere is high-purity argon with a purity of 99.999%; and the substrate is preheated to 150-170°C.

[0029] Furthermore, in step ②, the repair parameters are set as follows: laser power 350-400W, scanning speed 1100-1200mm / s, printing layer thickness 0.03mm, dot pitch 0.12mm, scanning strategy using 67° rotation scanning, and oxygen content in the repair chamber controlled below 100ppm.

[0030] Furthermore, in step ⑤, the environment of the repair chamber reaches the set values, specifically: the preheating temperature of the substrate in the repair chamber reaches 150℃~170℃; and the oxygen content in the repair chamber is <100ppm.

[0031] Furthermore, in step (9), the surface is finished to a surface roughness of Ra6.3μm.

[0032] The beneficial effects of this invention are:

[0033] First, laser powder bed melting technology is used to replace welding repair of aluminum alloy oil filter brackets. Al-Mg-Sc-Zr aluminum alloy powder is used as the repair material, which can realize rapid repair of oil filter brackets and overcome the shortcomings of traditional aluminum alloy welding repair, such as deformation, many weld defects and poor quality.

[0034] Secondly, laser powder bed melting repair technology was used to repair cracks in the cross-section of the oil filter. The performance of the oil filter support met the technical requirements, and the repaired molten interface was defect-free.

[0035] Third, the laser powder bed melting repair technology for repairing cracks in oil filters significantly shortens the cycle time compared to traditional machining of new parts. Attached Figure Description

[0036] Figure 1Schematic diagram of an aircraft oil filter bracket.

[0037] Figure 2 Schematic diagram of cross-sectional cracks in an aircraft oil filter support.

[0038] Figure 3 Image of a tensile specimen repaired from an aircraft furnace sample. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Example 1

[0041] A rapid repair method for aircraft oil filter brackets using laser powder bed melting includes the following steps:

[0042] (1) Cutting of the damaged area: The cross-sectional crack of the aircraft oil filter bracket is as follows Figure 2 As shown, the entire cracked end face of the aircraft oil filter bracket was cut off to obtain a horizontal cut surface.

[0043] (2) Grinding the cut surface: Grind the cut surface until the flatness is ≤0.05mm;

[0044] (3) Cleaning the cut surface: Wipe the cut surface with alcohol or acetone to remove surface oil and dirt;

[0045] (4) Model reconstruction of the damaged and cut parts: The three-dimensional model of the damaged and cut parts is reconstructed using a reverse scanner and the model is converted into STL format;

[0046] (5) Location of damaged parts: The position of damaged parts and the reference surface are measured using a coordinate measuring machine;

[0047] (6) Powder treatment for repair: The metal powder is vacuum dried. The metal powder includes the following components by mass percentage: Mg 4%, Sc 0.5%, Zr 0.2%, Mn 0.5%, Si 0.8%, Fe 0.3%, Zn 0.15%, O 0.04%, N 0.04%, with the balance being Al. The particle size of the metal powder is 20-63 μm and it is nearly spherical. The vacuum drying temperature is 8℃ and the vacuum drying time is 4h. After vacuum drying, the Hall flow rate of the metal powder is 25s / 50g.

[0048] (7) Preparation of the repair chamber for the laser powder bed fusion 3D printer: The repair chamber, including the galvanometer protective mirror and the scraper rubber strip, is cleaned by wiping with alcohol or acetone. The substrate material is aluminum alloy with a parallelism of 50μm. The protective atmosphere is high-purity argon with a purity of 99.999%. At the same time, the substrate is preheated to 150℃.

[0049] (8) Repair process:

[0050] ① Fix the aircraft oil filter bracket to be repaired onto the positioning fixture. The positioning fixture is fixed to the aluminum alloy base plate with bolts, and measure the coordinate points of the positioning fixture on the base plate.

[0051] ② Set the repair parameters as follows: laser power 350W, scanning speed 1100mm / s, printing layer thickness 0.03mm, dot pitch 0.12mm, scanning strategy adopts 67° rotation scanning, and oxygen content in the repair chamber is controlled at 10ppm;

[0052] ③ Apply powder to the area to be repaired using a rubber scraper. After the first application of powder, the cut end face of the area to be repaired is evenly covered with a thin layer of powder. The powder does not clump or agglomerate.

[0053] ④ Import the STL format 3D model reconstructed in step (4) into the data processing software, and place the model on the software-simulated substrate according to the coordinate points recorded in step ①. Then perform slice path planning to generate the damage area repair scanning path.

[0054] ⑤ The environment of the repair chamber reaches the set value: the preheating temperature of the substrate in the repair chamber reaches 150℃; the repair chamber oxygen content is 10ppm to start the repair process. The first scan laser remelts three times to ensure that the repair end face is melted through and well bonded with the reconstructed damage area. Subsequent lasers only need to scan each layer once.

[0055] ⑥ Repeatedly scan along the set scanning path until the damaged area is processed;

[0056] ⑦ Once the environment in the repair chamber has returned to room temperature, open the repair chamber and remove the repair parts.

[0057] (9) Finishing: The damaged repair area of ​​the part is finished to a surface roughness of Ra6.3μm.

[0058] Effect Experiment:

[0059] Preparation of furnace-fed specimens: Tensile specimens such as Figure 3As shown, the upper part is the substrate (original part material 2D70), and the lower part is the laser powder bed fusion repair part (material Al-Mg-Sc-Zr, same as in Example 1). The process parameters and procedures for the repair part are the same as those for the part repair in Example 1. Performance testing: The furnace-fed sample prepared simultaneously with the part repair was subjected to metallographic microstructure testing and room temperature tensile property testing. The fracture site of the tensile sample was the substrate part, with a tensile strength of 404 MPa and an elongation of 11%.

[0060] Example 2

[0061] A rapid repair method for aircraft oil filter brackets using laser powder bed melting includes the following steps:

[0062] (1) Cutting the damaged area: Cut off the entire end face of the aircraft oil filter bracket with cracks to obtain a horizontal cut surface;

[0063] (2) Grinding the cut surface: Grind the cut surface until the flatness is ≤0.05mm;

[0064] (3) Cleaning the cut surface: Wipe the cut surface with alcohol or acetone to remove surface oil and dirt;

[0065] (4) Model reconstruction of the damaged and cut parts: The three-dimensional model of the damaged and cut parts is reconstructed using a reverse scanner and the model is converted into STL format;

[0066] (5) Location of damaged parts: The position of damaged parts and the reference surface are measured using a coordinate measuring machine;

[0067] (6) Powder treatment for repair: The metal powder is vacuum dried. The metal powder includes the following components by mass percentage: Mg 9%, Sc 0.8%, Zr 0.5%, Mn 0.8%, Si 1.0%, Fe 0.4%, Zn 0.25%, O 0.05%, N 0.05%, with the balance being Al. The particle size of the metal powder is 20-63 μm and it is nearly spherical. The vacuum drying temperature is 100℃ and the vacuum drying time is 8h. After vacuum drying, the Hall flow rate of the metal powder is 40s / 50g.

[0068] (7) Preparation of the repair chamber for the laser powder bed fusion 3D printer: The repair chamber, including the galvanometer protective mirror and the scraper rubber strip, is cleaned by wiping with alcohol or acetone. The substrate material is aluminum alloy with a parallelism of 30μm. The protective atmosphere is high-purity argon with a purity of 99.999%. At the same time, the substrate is preheated to 170℃.

[0069] (8) Repair process:

[0070] ① Fix the aircraft oil filter bracket to be repaired onto the positioning fixture. The positioning fixture is fixed to the aluminum alloy base plate with bolts, and measure the coordinate points of the positioning fixture on the base plate.

[0071] ② Set the repair parameters as follows: laser power 400W, scanning speed 1200mm / s, printing layer thickness 0.03mm, dot pitch 0.12mm, scanning strategy adopts 67° rotation scanning, and the oxygen content in the repair chamber is controlled at 100ppm;

[0072] ③ Apply powder to the area to be repaired using a rubber scraper. After the first application of powder, the cut end face of the area to be repaired is evenly covered with a thin layer of powder. The powder does not clump or agglomerate.

[0073] ④ Import the STL format 3D model reconstructed in step (4) into the data processing software, and place the model on the software-simulated substrate according to the coordinate points recorded in step ①. Then perform slice path planning to generate the damage area repair scanning path.

[0074] ⑤ The environment of the repair chamber reaches the set value: the preheating temperature of the substrate in the repair chamber reaches 170℃; the oxygen content in the repair chamber is 100ppm to start the repair. The first scan laser remelts three times to ensure that the repair end face is melted through and well bonded with the reconstructed damage area. Subsequent lasers only need to scan each layer once.

[0075] ⑥ Repeatedly scan along the set scanning path until the damaged area is processed;

[0076] ⑦ Once the environment in the repair chamber has returned to room temperature, open the repair chamber and remove the repair parts.

[0077] (9) Finishing: The damaged repair area of ​​the part is finished to a surface roughness of Ra6.3μm.

[0078] Example 3

[0079] A rapid repair method for aircraft oil filter brackets using laser powder bed melting includes the following steps:

[0080] (1) Cutting the damaged area: Cut off the entire end face of the aircraft oil filter bracket with cracks to obtain a horizontal cut surface;

[0081] (2) Grinding the cut surface: Grind the cut surface until the flatness is ≤0.05mm;

[0082] (3) Cleaning the cut surface: Wipe the cut surface with alcohol or acetone to remove surface oil and dirt;

[0083] (4) Model reconstruction of the damaged and cut parts: The three-dimensional model of the damaged and cut parts is reconstructed using a reverse scanner and the model is converted into STL format;

[0084] (5) Location of damaged parts: The position of damaged parts and the reference surface are measured using a coordinate measuring machine;

[0085] (6) Powder treatment for repair: The metal powder is vacuum dried. The metal powder includes the following components by mass percentage: Mg 6.5%, Sc 0.65%, Zr 0.35%, Mn 0.65%, Si 0.9%, Fe 0.35%, Zn 0.2%, O ≤ 0.045%, N ≤ 0.045%, and the balance is Al. The particle size of the metal powder is 20-63 μm and it is nearly spherical. The vacuum drying temperature is 90℃ and the vacuum drying time is 6h. After vacuum drying, the Hall flow rate of the metal powder is 35s / 50g.

[0086] (7) Preparation of the repair chamber for the laser powder bed fusion 3D printer: The repair chamber, including the galvanometer protective mirror and the scraper rubber strip, is cleaned with alcohol or acetone. The substrate material is aluminum alloy with a parallelism of ≤50μm. The protective atmosphere is high-purity argon with a purity of 99.999%. At the same time, the substrate is preheated to 160℃.

[0087] (8) Repair process:

[0088] ① Fix the aircraft oil filter bracket to be repaired onto the positioning fixture. The positioning fixture is fixed to the aluminum alloy base plate with bolts, and measure the coordinate points of the positioning fixture on the base plate.

[0089] ② Set the repair parameters as follows: laser power 375W, scanning speed 1150mm / s, printing layer thickness 0.03mm, dot pitch 0.12mm, scanning strategy adopts 67° rotation scanning, and oxygen content in the repair chamber is controlled at 50ppm;

[0090] ③ Apply powder to the area to be repaired using a rubber scraper. After the first application of powder, the cut end face of the area to be repaired is evenly covered with a thin layer of powder. The powder does not clump or agglomerate.

[0091] ④ Import the STL format 3D model reconstructed in step (4) into the data processing software, and place the model on the software-simulated substrate according to the coordinate points recorded in step ①. Then perform slice path planning to generate the damage area repair scanning path.

[0092] ⑤ The environment of the repair chamber reaches the set value: the preheating temperature of the substrate in the repair chamber reaches 160℃; the repair chamber starts when the oxygen content is 50ppm. The first scan laser remelts three times to ensure that the repair end face is melted through and well bonded with the reconstructed damage area. Subsequent lasers only need to scan each layer once.

[0093] ⑥ Repeatedly scan along the set scanning path until the damaged area is processed;

[0094] ⑦ Once the environment in the repair chamber has returned to room temperature, open the repair chamber and remove the repair parts.

[0095] (9) Finishing: The damaged repair area of ​​the part is finished to a surface roughness of Ra6.3μm.

[0096] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for rapid repair of aircraft oil filter brackets using laser powder bed melting, characterized in that, Includes the following steps: (1) Cutting the damaged area: Cut off all the ends of the aircraft oil filter bracket with cracks to obtain a horizontal cut surface; (2) Grinding the cut surface: Grind the cut surface until it is smooth; (3) Cleaning the cut surface: Wipe the cut surface with alcohol or acetone to remove surface oil and dirt; (4) Model reconstruction of the damaged and cut parts: The three-dimensional model of the damaged and cut parts is reconstructed using a reverse scanner and the model is converted into STL format; (5) Location of damaged parts: The location of damaged parts and reference surfaces are measured using a coordinate measuring machine; (6) Powder treatment for repair: Vacuum drying of metal powder; (7) Preparation of the repair chamber for the laser powder bed fusion 3D printer: The repair chamber is cleaned with alcohol or acetone, the substrate material is aluminum alloy, the protective atmosphere is high-purity argon, and the substrate is preheated at the same time. (8) Repair process: ① Fix the aircraft oil filter bracket to be repaired onto the positioning fixture. The positioning fixture is fixed to the aluminum alloy base plate with bolts, and measure the coordinate points of the positioning fixture on the base plate. ② Set the repair parameters; ③ Apply powder to the area to be repaired using a rubber scraper. After the first application of powder, the cut end face of the area to be repaired is evenly covered with a thin layer of powder. The powder does not clump or agglomerate. ④ Import the STL format 3D model reconstructed in step (4) into the data processing software, and place the model on the software-simulated substrate according to the coordinate points recorded in step ①. Then perform slice path planning to generate the damage area repair scanning path. ⑤ Repair begins once the environment of the chamber to be repaired reaches the set value. The first scan involves three laser remelting steps to ensure that the repaired end face is fully melted and well bonded with the reconstructed damage area. Subsequent laser scans only need to be performed once per layer. ⑥ Repeatedly scan along the set scanning path until the damaged area is processed; ⑦ Once the environment in the repair chamber has returned to room temperature, open the repair chamber and remove the repair parts; (9) Finishing: Finishing the damaged parts of the parts; In step (6), the metal powder comprises the following components by mass percentage: Mg 4%~9%, Sc 0.5%~0.8%, Zr 0.2%~0.5%, Mn≤0.8%, Si≤1.0%, Fe≤0.4%, Zn≤0.25%, O≤0.05%, N≤0.05%, with the balance being Al.

2. The rapid repair method for aircraft oil filter brackets using laser powder bed melting according to claim 1, characterized in that, In step (2), the flatness is ground to ≤0.05 mm.

3. The rapid repair method for aircraft oil filter brackets using laser powder bed melting according to claim 1, characterized in that, In step (6), the metal powder has a particle size of 20~63μm and is nearly spherical.

4. The rapid repair method for aircraft oil filter brackets using laser powder bed melting according to claim 1, characterized in that, In step (6), the temperature of vacuum drying is 80~100℃, the time of vacuum drying is 4~8h, and the Hall flow rate of the metal powder after vacuum drying is <50s / 50g.

5. The rapid repair method for aircraft oil filter brackets using laser powder bed melting according to claim 1, characterized in that, In step (7), the galvanometer protective mirror and scraper rubber strip of the repair chamber are cleaned with alcohol or acetone.

6. The rapid repair method for aircraft oil filter brackets using laser powder bed melting according to claim 1, characterized in that, In step (7), the substrate material is an aluminum alloy with a parallelism of ≤50 μm; the protective atmosphere is high-purity argon with a purity of 99.999%; and the substrate is preheated to 150~170℃.

7. The rapid repair method for aircraft oil filter brackets using laser powder bed melting according to claim 1, characterized in that, In step ②, the repair parameters are set as follows: laser power 350~400W, scanning speed 1100~1200mm / s, printing layer thickness 0.03mm, dot pitch 0.12mm, scanning strategy adopts 67° rotation scanning, and the oxygen content in the repair chamber is controlled below 100 ppm.

8. The rapid repair method for aircraft oil filter brackets using laser powder bed melting according to claim 1, characterized in that, In step ⑤, the environment of the repair chamber reaches the set values, specifically: the preheating temperature of the substrate in the repair chamber reaches 150℃~170℃; and the oxygen content in the repair chamber is <100ppm.

9. The rapid repair method for aircraft oil filter brackets using laser powder bed melting according to claim 1, characterized in that, In step (9), the surface is finished to a roughness of Ra6.3μm.

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