Forming method of titanium alloy hinge structure

Abstract

The invention discloses a forming method of a titanium alloy hinge structure, which comprises the following steps: firstly, selecting additive forming equipment to complete blank forming, and forming a cylindrical section on a small end face of a blank as a process chuck; a positioning tool is manufactured, and a positioning hole capable of clamping the blank is formed in the positioning tool; the process chuck is clamped by a chuck on one side of turning and milling equipment, turning and milling operation is carried out, and machining of the inner profile and the outer profile of the blank is completed; a chuck on the other side of the turning and milling equipment clamps the positioning tool, the blank is taken down and turned over, the blank is positioned through the positioning hole, turning and milling operation is conducted, the process chuck is removed, and a primary part product is obtained; performing deburring treatment on corners and orifices of the part primary product, and polishing the surface until the roughness requirement is met; and after the requirements are met, finished parts are obtained, the machining procedures and the clamping frequency are reduced, the clamping difficulty of the special-shaped parts is lowered, efficiency is improved, and cost is reduced.

Description

Technical Field

[0001] This application relates to the field of titanium alloy parts forming technology, and in particular to a forming method for a titanium alloy hinge structure. Background Technology

[0002] In the aerospace field, the performance and reliability of aircraft depend on the material properties and processing quality of each key structural component. Among them, titanium alloys, with their high strength, low density, excellent fatigue resistance, strong corrosion resistance and excellent high and low temperature adaptability, have become the ideal material for manufacturing core structural components of aircraft and are widely used in key parts such as fuselage frames, engine components and wing surface connection structures.

[0003] Titanium alloy hinge joint components, as core load-bearing and transmission parts on aircraft wings, directly affect wing deployment, retraction, and flight attitude control. Their machining quality and precision have a decisive impact on the overall safety and handling stability of the aircraft. However, current machining techniques for these titanium alloy hinge joint components face numerous insurmountable drawbacks due to material properties and product structure characteristics. These include: high tool wear and machining costs, difficult clamping and inconsistent precision, cumbersome and inefficient machining processes, and long production cycles with challenging cost control. Existing machining technologies for titanium alloy hinge joint components exhibit significant deficiencies in cost control, clamping accuracy, machining efficiency, and adaptability to mass production. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application provides a method for forming titanium alloy hinge structures, thereby solving the problems of high forming cost, low precision, and low efficiency in the forming of titanium alloy structures in existing technologies.

[0005] The above-mentioned objectives of this application are mainly achieved through the following technical solutions: A method for forming a titanium alloy hinge structure, the method comprising: Additive molding equipment is selected to complete the blank forming, and a cylindrical segment is formed on the small end face of the blank as a process chuck; A positioning fixture is fabricated, wherein the positioning fixture is provided with positioning holes for clamping the blank; The process chuck is held in a chuck on one side of the milling and turning equipment to perform milling and turning operations, thereby completing the machining of the inner and outer surfaces of the blank. The positioning fixture is clamped in the chuck on the other side of the milling machine, and the blank is removed and flipped. The blank is positioned through the positioning hole and milled to remove the process chuck and obtain the initial part. The edges and openings of the initial part are deburred, and the surface is polished until the roughness requirements are met. After quality inspection, the finished part is obtained once it meets the requirements.

[0006] In an optional implementation, when selecting additive molding equipment for blank forming, a processing allowance is reserved for the blank based on the forming accuracy of the additive molding equipment.

[0007] In an optional implementation, when reserving machining allowance for the blank, a machining allowance of 2-4mm is reserved on one side based on the final design dimensions of the part.

[0008] In an optional implementation, when forming the small end face of the blank using a chuck, the additive molding equipment integrally forms a cylindrical segment with a length of 20-30mm, the diameter of which matches the clamping range of the chuck of the milling and turning equipment.

[0009] In an optional embodiment, when machining the inner and outer surfaces of the blank, rough machining is performed first, then the process chuck is removed, and the end face of the removed process chuck is machined. After the part is re-clamped with the end face as a positioning reference, fine machining is performed to obtain the initial part.

[0010] In an optional implementation, during rough machining, an alloy milling cutter is first used to rough mill the shape, machining along the contour path of the part, with a 0.5mm allowance reserved on each side. The milling speed is controlled at 800-1000r / min, and the feed rate is 80-100mm / min.

[0011] In an optional implementation, after rough milling of the outer shape, rough boring is performed using an internal boring tool. The internal hole structure of the part is machined in the order from large hole to small hole, with a 0.5mm allowance on each side. The boring speed is 600-800r / min, the feed rate is 50-70mm / min, and the roughness of the inner hole wall is kept not greater than 12.5μm.

[0012] In an optional implementation, during finishing, precision milling and precision boring are performed using cutting tools until the dimensional tolerance of the outer surface is controlled within ±0.03mm, the surface roughness is not greater than 3.2μm, the roundness of the inner hole is not greater than 0.01mm, the cylindricity is not greater than 0.02mm, and the surface roughness is not greater than 1.6μm.

[0013] In an optional implementation, during finishing, the boring and milling speeds are increased to 1200-1500 r / min, and the feed rate is reduced to 30-50 mm / min.

[0014] In an optional implementation, when performing quality inspection, the dimensions of the parts are first checked with calipers and micrometers. After confirming that the dimensions meet the requirements, the quality inspection is carried out by coordinate measuring machine and / or mechanical property testing until the finished parts meet the requirements.

[0015] Compared with the prior art, the advantages of this application are: The forming method in this application is used for forming titanium alloy hinge structures. The forming method includes: selecting additive forming equipment to complete blank forming, and forming a cylindrical segment on the small end face of the blank as a process chuck; making a positioning fixture, the positioning fixture having positioning holes for clamping the blank; clamping the process chuck with a chuck on one side of a milling machine, performing milling operations to complete the machining of the inner and outer surfaces of the blank; clamping the positioning fixture with a chuck on the other side of the milling machine, removing the blank and flipping it, positioning the blank through the positioning holes, performing milling operations, removing the process chuck, and obtaining a preliminary part; deburring the edges and openings of the preliminary part, and grinding the surface until the roughness requirements are met; performing quality inspection, and obtaining the finished part after meeting the requirements.

[0016] The forming method first uses additive manufacturing equipment to form the blank, and integrally forms a cylindrical section on the small end face of the blank as a process chuck. Then, a suitable positioning fixture is made, which has a pre-set positioning hole for stable clamping of the blank. In the machining stage, the process chuck of the blank is directly clamped by the chuck on one side of the milling machine. The milling and turning of the inner and outer surfaces of the blank is completed by the rotation of the chuck and the feed of the tool. After the machining of one side is completed, the positioning fixture is clamped by the chuck on the other side of the milling machine. The blank is removed from the chuck on one side and flipped. The positioning hole of the positioning fixture is used to achieve rapid and accurate positioning of the blank. Then, the remaining machining is completed by the rotation of the chuck on the other side and the feed of the tool, and the process chuck is removed to obtain the initial part. After deburring of the edges and holes, the surface is polished to meet the roughness requirements. Finally, the finished part is obtained after quality inspection.

[0017] This forming method precisely addresses existing defects through multi-stage collaboration: additive forming directly manufactures blanks close to the final shape, significantly reducing blank allowance and resulting in a substantial reduction in cutting volume during milling and turning. Combined with the design of the process chuck, the chuck on one side of the milling and turning equipment can achieve high-speed rotation by stably clamping the cylindrical process chuck. The tool only needs to make a small feed to complete the surface machining, which reduces cutting force and cutting temperature, reduces tool wear, and shortens cutting time. The matching design of the positioning holes of the positioning fixture with the blank, as well as the switching use of the two chucks, allows for quick clamping after the blank is flipped without repeated adjustment of the reference. Precise positioning through the positioning holes enables quick clamping, avoiding uneven clamping force and positioning deviation. At the same time, the independent movement and coordinated operation of the two chucks reduce the number of clamping operations and avoid the accumulation of errors from multiple clamping operations. The process chuck, as a temporary clamping structure, not only solves the problem of difficult direct clamping of irregularly shaped blanks, but also allows for precise cutting removal by the tool in subsequent processing without the need for additional tooling, further simplifying the process.

[0018] On the one hand, it integrates additive manufacturing with milling and turning, reducing machining steps and clamping times. On the other hand, the design of process chucks and positioning fixtures reduces the difficulty of clamping irregularly shaped parts, improving machining accuracy and stability. Tool wear is reduced, significantly decreasing tooling costs; clamping time is shortened, increasing single-piece machining efficiency; machining accuracy is improved, shortening batch production cycles, and reducing overall manufacturing costs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic flowchart illustrating the molding method provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the billet provided in the embodiments of this application; Figure 3 A schematic diagram of the structure of the part provided in the embodiments of this application. In the diagram: 100, part; 200, blank; 300, process chuck. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that the description of these embodiments is intended to aid in understanding the invention, but does not constitute a limitation thereof. The specific structural and functional details disclosed herein are merely for describing exemplary embodiments of the invention. However, the invention can be embodied in many alternative forms and should not be construed as being limited to the embodiments described herein.

[0022] In the aerospace field, the performance and reliability of aircraft depend on the material properties and processing quality of each key structural component. Among them, titanium alloys, with their high strength, low density, excellent fatigue resistance, strong corrosion resistance and excellent high and low temperature adaptability, have become the ideal material for manufacturing core structural components of aircraft and are widely used in key parts such as fuselage frames, engine components and wing surface connection structures.

[0023] Titanium alloy hinge joint components, as core load-bearing and transmission parts on aircraft wings, are directly related to wing deployment, retraction, and flight attitude control. Their machining quality and precision have a decisive impact on the overall safety and handling stability of the aircraft. However, current machining techniques for these titanium alloy hinge joint components face several insurmountable shortcomings due to material properties and product structural characteristics. These shortcomings are specifically reflected in the following aspects: The high strength and hardness of titanium alloys mean they must withstand cutting forces far exceeding those of ordinary metals during machining. Simultaneously, titanium alloys have low thermal conductivity, making it difficult for heat generated during cutting to dissipate quickly. This results in a concentration of heat in the cutting area, causing a sharp rise in cutting temperature. Excessive cutting temperature and force not only accelerate tool wear and chipping, shortening tool life, but also necessitate frequent replacements of specialized high-precision tools, significantly increasing tool procurement and replacement costs. This leads to persistently high tooling costs per machining operation, directly driving up the manufacturing cost of the parts.

[0024] Titanium alloy hinge joint components are typical irregularly shaped composite surface structures with stringent precision requirements for critical mating surfaces and a lack of stable clamping reference surfaces. Current machining processes require complex tooling designs or multiple adjustments to the clamping position to fix the parts. This is not only cumbersome and time-consuming, but also prone to deformation or displacement during machining due to uneven clamping force distribution or positioning deviations. This affects the accuracy of critical dimensions and geometric tolerances, making it difficult to meet the high-precision assembly requirements of aircraft for such components and increasing the risk of producing defective products.

[0025] These types of parts are typically machined from titanium alloy forgings. Due to the large allowance in the forging blanks and the complex structure of the parts, existing machining processes require multiple clamping and multi-step operations to gradually remove excess material in order to achieve the design dimensions and accuracy requirements. Multiple clamping not only further affects machining accuracy due to the accumulation of positioning errors, but also increases the waiting time between processes and results in poor continuity of the machining process. At the same time, the difficult-to-cut characteristics of titanium alloys limit the feed rate and cutting speed of a single cut, further extending the machining time per part. Overall, the machining efficiency is low and it is difficult to meet the needs of mass production.

[0026] Given the aforementioned problems of high tool wear, difficult clamping, and low machining efficiency, these defects are further amplified during mass production: on the one hand, frequent tool changes and complex clamping operations lead to extended single-piece machining cycles, significantly increasing the overall cycle of mass production, making it difficult to meet the aerospace industry's demand for rapid delivery of parts; on the other hand, the combined costs of tooling, fixture design, rework of defective products, and manual operation result in persistently high total costs for mass production, severely restricting the large-scale application and cost optimization of such key titanium alloy parts.

[0027] In summary, existing processing technologies for titanium alloy hinge structure joint parts have significant shortcomings in terms of cost control, clamping accuracy, processing efficiency, and adaptability to mass production.

[0028] like Figure 1 , Figure 2 as well as Figure 3As shown, Figure 1 A schematic flowchart illustrating the molding method provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the billet provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of a part provided in an embodiment of this application.

[0029] like Figure 1 As shown, a method for forming a titanium alloy hinge structure includes: like Figure 2 As shown, additive manufacturing equipment is selected to complete the forming of blank 200, and a cylindrical segment is formed on the small end face of blank 200 as a process chuck 300; A positioning fixture is fabricated, wherein the positioning fixture is provided with positioning holes for clamping the blank 200; The process chuck 300 is held in a chuck on one side of the milling and turning equipment to perform milling and turning operations, thereby completing the machining of the inner and outer surfaces of the blank 200; The positioning fixture is clamped in the chuck on the other side of the milling machine, and the blank 200 is removed and flipped. The blank 200 is positioned through the positioning hole and milling is performed. The process chuck 300 is removed to obtain the initial part 100. The edges and openings of the initial part 100 are deburred, and the surface is polished until the roughness requirements are met. like Figure 3 As shown, after quality inspection, 100 finished parts were obtained after meeting the requirements.

[0030] When selecting additive manufacturing equipment to complete the forming of blank 200, based on the three-dimensional design model of titanium alloy hinge structure joint part 100, a suitable metal additive manufacturing equipment (such as laser selective melting additive manufacturing equipment, with laser power set to 180-220W and scanning speed of 800-1200mm / s) is selected. Using TC4 titanium alloy powder as raw material, blank 200 is formed according to the preset forming path. During the forming process of blank 200, a cylindrical section is integrally formed on the small end face of blank 200 as a process chuck 300. The axis of the process chuck 300 coincides with the reference axis of the core surface of blank 200 to ensure the positioning accuracy during subsequent clamping and to provide a stable contact surface for chuck clamping.

[0031] Subsequently, a positioning fixture is manufactured according to the external dimensions and positioning requirements of the blank 200. The positioning fixture can be made of 45 steel after quenching and tempering (hardness up to HRC28-32) to ensure the structural strength and wear resistance of the fixture. Positioning holes adapted to the non-machined surfaces of the blank 200 are opened on the positioning fixture. The diameter of the positioning hole is 0.01-0.02mm larger than the diameter of the corresponding mating surface of the blank 200, to ensure that the blank 200 can be accurately positioned after being loaded, and to avoid clamping deformation caused by excessive constraint. The inner wall of the positioning hole can be honed to reduce frictional damage to the blank 200 during clamping.

[0032] Upon entering the milling and turning stage, the three-jaw self-centering chuck on one side of the milling and turning equipment (such as a horizontal milling and turning composite machine tool) is first cleaned and its precision calibrated. Then, the process chuck 300 of the blank 200 is inserted into the chuck jaws, and stable clamping is achieved through the radial clamping motion of the chuck. At this time, the milling and turning equipment is started, and the milling and turning tool (carbide coated tool) performs axial and radial feed motion according to the preset machining path, sequentially completing the milling and turning of the inner hole, outer cylindrical stepped surface and irregular surface of the blank 200. During the machining process, water-soluble cutting fluid is sprayed through the equipment's built-in cooling system to reduce the cutting temperature in real time, thereby reducing tool wear and thermal deformation of the blank 200.

[0033] After one side is processed, stop the chuck rotation and release the clamping device. Remove the blank 200 and rotate it 180° along the axis of the process chuck 300. At the same time, clamp the positioning fixture with the three-jaw chuck on the other side of the milling machine. Fix the fixture by centering the outer cylindrical surface of the fixture with the chuck. Then, put the non-machined surface of the rotated blank 200 into the positioning hole of the positioning fixture. Through the guiding and positioning effect of the positioning hole, the machined surface of the blank 200 is precisely aligned with the milling cutter. At this time, start the milling machine again. The chuck drives the positioning fixture and the blank 200 to rotate. The milling cutter feeds according to the preset path. First, the remaining surface of the blank 200 is machined. Then, the radial cutting motion of the cutter is used to precisely remove the process chuck 300, and the initial part 100 with the dimensional and geometric tolerances initially met the requirements is obtained.

[0034] After the initial processing of part 100 is completed, deburring equipment can be used to deburr the edges, corners, holes and junctions of the surface of part 100 to ensure that all sharp burrs and flash are removed. Then, surface treatment is carried out by combining grinding wheel grinding and sandpaper polishing. First, use an 800-grit alumina grinding wheel for rough grinding, and then use 1200-grit and 2000-grit silicon carbide sandpaper for fine polishing until the surface roughness of part 100 meets the requirements.

[0035] In an optional embodiment, the forming method of this application is used for forming titanium alloy hinge structures. The forming method includes: selecting additive forming equipment to form a blank 200, and forming a cylindrical segment on the small end face of the blank 200 as a process chuck 300; making a positioning fixture, the positioning fixture having positioning holes for clamping the blank 200; clamping the process chuck 300 with a chuck on one side of a milling machine, performing milling operations to complete the machining of the inner and outer surfaces of the blank 200; clamping the positioning fixture with a chuck on the other side of the milling machine, removing the blank 200 and flipping it, positioning the blank 200 through the positioning holes, performing milling operations to remove the process chuck 300, obtaining a preliminary part 100; deburring the edges and openings of the preliminary part 100, and grinding the surface until the roughness requirements are met; performing quality inspection, and obtaining the finished part 100 after meeting the requirements.

[0036] The forming method first uses additive manufacturing equipment to form the blank 200, and integrally forms a cylindrical section on the small end face of the blank 200 as the process chuck 300. Then, a suitable positioning fixture is made, which has a pre-set positioning hole for stably clamping the blank 200. In the machining stage, the process chuck 300 of the blank 200 is directly clamped by the chuck on one side of the milling machine. Through the rotation of the chuck and the feed of the tool, the milling of the inner and outer surfaces of the blank 200 is completed. After the machining on one side is completed, the positioning fixture is clamped by the chuck on the other side of the milling machine. The blank 200 is removed from the chuck on one side and flipped. The positioning hole of the positioning fixture is used to achieve fast and accurate positioning of the blank 200. Then, through the rotation of the chuck on the other side and the feed of the tool, the remaining machining is completed and the process chuck 300 is removed to obtain the initial part 100. After deburring of the edges and holes and surface grinding to meet the roughness requirements, the final part 100 is obtained after quality inspection.

[0037] This forming method precisely addresses existing defects through multi-stage collaboration: additive forming directly manufactures a near-final shape blank 200, significantly reducing the blank allowance and resulting in a substantial reduction in cutting volume during milling and turning. Combined with the design of the process chuck 300, the chuck on one side of the milling and turning equipment can achieve high-speed rotation by stably clamping the cylindrical process chuck 300. The tool only needs to make a small feed to complete the surface machining, which reduces cutting force and cutting temperature, reduces tool wear, and shortens cutting time. The matching design of the positioning holes of the positioning fixture with the blank 200, as well as the switching use of the two chucks, allows the clamping of the blank 200 after flipping to achieve quick clamping without repeated adjustment of the reference. This avoids uneven clamping force and positioning deviation. At the same time, the independent movement and coordinated operation of the two chucks reduce the number of clamping operations and avoid the accumulation of errors from multiple clamping operations. The process chuck 300, as a temporary clamping structure, not only solves the problem of the difficulty in directly clamping the irregularly shaped blank 200, but also allows it to be precisely removed by cutting tools in subsequent processing without the need for additional tooling, further simplifying the process.

[0038] On the one hand, it integrates additive manufacturing and milling / turning, reducing machining steps and clamping times. On the other hand, the design of the 300 process chuck and positioning fixtures reduces the difficulty of clamping irregularly shaped parts, improving machining accuracy and stability. Tool wear is reduced, significantly decreasing tooling costs; clamping time is shortened, increasing single-piece machining efficiency; machining accuracy is improved, shortening batch production cycles, and reducing overall manufacturing costs.

[0039] In an optional implementation, when selecting additive molding equipment to form the blank 200, a processing allowance for the blank 200 is reserved according to the forming accuracy of the additive molding equipment.

[0040] To balance additive manufacturing efficiency and subsequent milling accuracy, a machining allowance of 200mm is reserved in the blank based on the forming accuracy of the additive manufacturing equipment. Different additive manufacturing equipment, such as laser selective melting and electron beam melting, have varying forming accuracies. Directly forming to the final dimensions can easily lead to insufficient or excessive machining allowance due to equipment accuracy deviations. Insufficient allowance prevents milling from correcting surface defects such as micropores and interlayer steps, while excessive allowance increases cutting load and prolongs processing time. Reserved machining allowance ensures that subsequent milling can completely remove surface defects from the additive manufacturing process while avoiding unnecessary cutting wear, and provides sufficient adjustment space for precise control of the final dimensions of part 100.

[0041] In an optional implementation, when reserving machining allowance for blank 200, a machining allowance of 2-4mm is reserved on one side based on the final design dimensions of part 100.

[0042] On the one hand, traditional machining of titanium alloy forging blanks requires a 5-8mm allowance to account for forging defects. However, this solution uses additively formed blank 200, which has significantly better surface quality and dimensional accuracy than forgings, thus reducing the allowance. On the other hand, a 2-4mm single-sided allowance can meet the requirements of two-step machining. In the roughing stage, the overall shape deviation of the additive blank 200 can be quickly corrected, and in the finishing stage, the dimensional tolerance and surface roughness of the part 100 can be guaranteed. At the same time, this allowance range can be adapted to the cutting parameters of common milling and turning tools, avoiding tool breakage due to excessive allowance or multiple passes due to insufficient allowance, thus balancing machining efficiency and tool life.

[0043] In an optional embodiment, when the small end face of the blank 200 is formed by the chuck 300, the additive molding equipment integrally forms a cylindrical segment with a length of 20-30mm, the diameter of which matches the clamping range of the chuck of the milling and turning equipment.

[0044] This design solves the problems of difficult positioning and easy deformation of irregularly shaped parts in traditional tooling. The 20-30mm length meets the stable clamping requirements of the chuck. If the cylindrical section length is less than 20mm, the contact area between the chuck jaws and the process chuck 300 is too small, which can easily lead to deformation of the process chuck 300 due to concentrated clamping force. If the cylindrical section length is greater than 30mm, it will increase the cutting amount required to remove the process chuck 300 in the subsequent process, prolonging the machining time. Secondly, the diameter of the cylindrical section needs to be compatible with the clamping range of the turning and milling machine chuck. This ensures that the chuck jaws apply uniform clamping force to the cylindrical section (avoiding slippage due to an insufficient diameter or over-range chuck due to an excessive diameter), and also ensures that the axis of the process chuck 300 is precisely aligned with the axis of rotation of the chuck, reducing clamping eccentricity errors and providing a basis for coaxiality control in subsequent turning and milling processes.

[0045] In an optional embodiment, when machining the inner and outer surfaces of the blank 200, rough machining is performed first, then the process chuck 300 is removed, and the end face of the removed process chuck 300 is machined. After the part 100 is re-clamped with the end face as a positioning reference, fine machining is performed to obtain the initial part 100.

[0046] In traditional processes, if the process chuck 300 is always used as the reference for roughing and finishing, the cutting heat generated during roughing can easily cause slight deformation of the process chuck 300, which in turn causes the positioning reference to shift during finishing, affecting the accuracy of part 100. First, roughing is performed to quickly remove most of the excess material. At this point, the overall shape of part 100 is close to the final design. Then, the process chuck 300 is removed and the end face is machined, making this end face the new positioning reference. This reference is directly related to the core functional surfaces of part 100 and reflects the actual machining state of part 100 better than the process chuck 300. During reclamping, end face positioning combined with external diameter auxiliary positioning can further reduce clamping errors, ensuring that the tool can accurately align with the machined surface of part 100 during finishing, significantly improving the dimensional consistency and geometric tolerance accuracy of the inner and outer surfaces.

[0047] In an optional implementation, during rough machining, an alloy milling cutter is first used to rough mill the shape, machining along the outline path of part 100, with a 0.5mm allowance reserved on each side. The milling speed is controlled at 800-1000r / min, and the feed rate is 80-100mm / min.

[0048] Choosing an alloy end mill allows it to withstand the high cutting forces during rough machining of titanium alloys, preventing rapid tool wear. Secondly, machining along the contour path reduces idle time and improves rough machining efficiency. The 0.5mm single-sided allowance provides adjustment space for finishing, ensuring that the surface texture of the roughing is corrected without excessive cutting during finishing. The combination of a milling speed of 800-1000 r / min and a feed rate of 80-100 mm / min allows the cutting speed to be controlled at 20-30 m / min, ensuring a high material removal rate while avoiding a sudden rise in cutting temperature due to excessive speed. Temperatures exceeding 600℃ will exacerbate the chemical affinity between titanium alloys and tools, leading to tool sticking, or tool chatter due to excessive feed rate.

[0049] In an optional implementation, after rough milling of the outer shape, rough boring is performed using an internal boring tool. The internal hole structure of part 100 is machined in the order from large hole to small hole, with a 0.5mm allowance reserved on each side. The boring speed is 600-800r / min, the feed rate is 50-70mm / min, and the roughness of the inner hole wall is kept not greater than 12.5μm.

[0050] The machining sequence from large hole to small hole avoids interference between the tool and the already machined large hole wall during small hole machining. Simultaneously, the large hole machining provides an auxiliary observation window for subsequent small hole machining, facilitating operator monitoring of the machining status. The rigidity of the internal boring tool is weaker than that of the external milling tool, and the boring speed is lower than that of the external milling speed, with a correspondingly reduced feed rate to minimize tool chatter and ensure the roundness of the internal hole. A 0.5mm allowance is reserved on each side, consistent with the roughing of the outer shape, ensuring uniform machining during finish boring. The requirement that the internal hole wall roughness not exceed 12.5μm prevents excessive roughness from causing uneven cutting resistance during finish boring, which would affect the finishing accuracy.

[0051] In an optional implementation, during finishing, precision milling and precision boring are performed using cutting tools until the dimensional tolerance of the outer surface is controlled within ±0.03mm, the surface roughness is not greater than 3.2μm, the roundness of the inner hole is not greater than 0.01mm, the cylindricity is not greater than 0.02mm, and the surface roughness is not greater than 1.6μm.

[0052] The tolerance of ±0.03mm on the outer surface ensures precise fit between the hinge and other components of the wing surface, avoiding vibration and noise caused by excessive assembly clearance; the roundness of 0.01mm and the cylindricity of 0.02mm in the inner hole ensure smooth rotation of the hinge shaft and reduce wear; the differentiated surface roughness requirements are because the inner hole, as a moving mating surface, requires lower roughness to reduce the coefficient of friction and extend service life, while the outer surface mainly needs to meet the requirements of appearance and assembly positioning, and appropriately relaxing the roughness requirements can improve processing efficiency.

[0053] In an optional implementation, during finishing, the boring and milling speeds are increased to 1200-1500 r / min, and the feed rate is reduced to 30-50 mm / min.

[0054] The machining allowance in the finishing stage is only 0.5mm, eliminating the need for a high material removal rate. By increasing the spindle speed, the contact time between the tool and the workpiece can be reduced, decreasing cutting heat generation and preventing precision deviations in titanium alloys caused by thermal deformation. Simultaneously, reducing the feed rate decreases the amount of material removed per tooth, reducing cutting force fluctuations and resulting in a more uniform surface texture, thus achieving the preset surface roughness requirements. Furthermore, this combination of spindle speed and feed rate can be adapted to the performance characteristics of finishing tools, fully leveraging the cutting advantages of high-precision tools and avoiding wasted tool performance due to improper parameters.

[0055] In an optional implementation, when performing quality inspection, the dimensions of part 100 are first checked with calipers and micrometers. After confirming that the dimensions meet the requirements, a coordinate measuring machine and / or mechanical property test are used to perform quality inspection until the finished part 100 is obtained that meets the requirements.

[0056] Calipers and micrometers, as rapid inspection tools, can initially screen the key linear dimensions of part 100, eliminating parts that are significantly out of tolerance and avoiding the waste of resources in subsequent high-precision inspections. Secondly, a coordinate measuring machine (CMM) can comprehensively inspect the complex surfaces and geometric tolerances of part 100, ensuring that its geometric accuracy meets design requirements. Mechanical property testing, such as tensile strength and hardness testing, is crucial for the safety of titanium alloy hinges. Since the additive manufacturing process may affect the mechanical properties of titanium alloys, and residual stress may exist, testing is necessary to confirm the tensile strength and hardness of part 100, avoiding risks due to insufficient mechanical properties. For small-batch production, CMM and mechanical property testing can be performed simultaneously to ensure comprehensiveness; for large-batch production, sampling can be used for mechanical property testing, improving inspection efficiency while ensuring quality.

[0057] It should be understood that the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. Although the terms "first," "second," etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another. For example, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit, without departing from the scope of the exemplary embodiments of the invention.

[0058] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" in this article describes another relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the related objects before and after it are in an "or" relationship.

[0059] It should be understood that in the description of this invention, the terms "upper," "vertical," "inner," "outer," etc., indicate the orientation or positional relationship as commonly placed when the disclosed product is used, or the orientation or positional relationship commonly understood by those skilled in the art. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0060] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0061] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” “containing,” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, and do not exclude the presence or addition of one or more other features, quantities, steps, operations, units, components, and / or combinations thereof.

[0062] Specific details are provided in the following description to provide a complete understanding of the exemplary embodiments. However, those skilled in the art will understand that the exemplary embodiments can be implemented without these specific details. In other embodiments, well-known processes, structures, and techniques may be omitted in the depiction of non-essential details to avoid obscuring the exemplary embodiments.

[0063] The above are merely specific embodiments of this application, enabling those skilled in the art to understand or implement this application. 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 this application. Therefore, this application 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 claimed herein.

[0064] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art.

Claims

1. A method for forming a titanium alloy hinge structure, characterized in that, The molding method includes: Additive molding equipment is selected to complete the blank forming, and a cylindrical segment is formed on the small end face of the blank as a process chuck; A positioning fixture is fabricated, wherein the positioning fixture is provided with positioning holes for clamping the blank; The process chuck is held in a chuck on one side of the milling and turning equipment to perform milling and turning operations, thereby completing the machining of the inner and outer surfaces of the blank. The positioning fixture is clamped in the chuck on the other side of the milling machine, and the blank is removed and flipped. The blank is positioned through the positioning hole and milled to remove the process chuck and obtain the initial part. The edges and openings of the initial part are deburred, and the surface is polished until the roughness requirements are met. After quality inspection, the finished part is obtained once it meets the requirements.

2. The forming method of the titanium alloy hinge structure as described in claim 1, characterized in that: When selecting additive molding equipment for blank forming, allowance should be reserved for blank processing based on the forming accuracy of the additive molding equipment.

3. The forming method of the titanium alloy hinge structure as described in claim 2, characterized in that: When reserving machining allowance for blanks, a machining allowance of 2-4mm should be reserved on one side based on the final design dimensions of the part.

4. The forming method of the titanium alloy hinge structure as described in claim 1, characterized in that: When forming the small end face of the blank in the process chuck, the additive molding equipment integrally forms a cylindrical segment with a length of 20-30mm, and the diameter of the cylindrical segment matches the clamping range of the chuck of the turning and milling equipment.

5. The forming method of the titanium alloy hinge structure as described in claim 1, characterized in that: When machining the inner and outer surfaces of the blank, rough machining is performed first, then the process chuck is removed, and the end face of the removed process chuck is machined. After the part is re-clamped with the end face as the positioning reference, fine machining is performed to obtain the initial part.

6. The forming method of the titanium alloy hinge structure as described in claim 5, characterized in that: When performing rough machining, first use an alloy milling cutter to rough mill the shape, machining along the outline path of the part, and leaving a 0.5mm allowance on each side. The milling speed is controlled at 800-1000r / min, and the feed rate is 80-100mm / min.

7. The forming method of the titanium alloy hinge structure as described in claim 6, characterized in that: After rough milling of the outer shape, rough boring is performed using an internal boring tool. The internal hole structure of the part is machined in the order from large hole to small hole, with a 0.5mm allowance on each side. The boring speed is 600-800r / min, the feed rate is 50-70mm / min, and the roughness of the inner hole wall is kept not greater than 12.5μm.

8. The forming method of the titanium alloy hinge structure as described in claim 7, characterized in that: During finishing, use cutting tools for precision milling and precision boring until the external surface dimensional tolerance is controlled within ±0.03mm, the surface roughness is not greater than 3.2μm, the roundness of the inner hole is not greater than 0.01mm, the cylindricity is not greater than 0.02mm, and the surface roughness is not greater than 1.6μm.

9. The forming method of the titanium alloy hinge structure as described in claim 8, characterized in that: During finishing, the boring and milling speeds are increased to 1200-1500 r / min, and the feed rate is reduced to 30-50 mm / min.

10. The forming method of the titanium alloy hinge structure as described in claim 1, characterized in that: When conducting quality inspection, first use calipers and micrometers to check the dimensions and specifications of the parts. After confirming that the dimensions and specifications meet the requirements, use coordinate measuring machines and / or mechanical property tests to conduct quality inspection until the finished parts meet the requirements.

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