A forming die and a hydraulic forming method for M-shaped aircraft longitudinal profile parts

Abstract

The application discloses a forming die, which comprises a die body and a die cover plate, wherein the die body comprises a bottom plate, die reinforcing bosses and die reinforcing platforms; a plurality of die reinforcing platforms are arranged on the two sides of the bottom plate; a plurality of die reinforcing platforms are uniformly arranged on one side of the bottom plate, and one die reinforcing platform is arranged on the other side of the bottom plate; the die reinforcing platforms on the two sides of the bottom plate are correspondingly arranged; a plurality of die reinforcing bosses are arranged on the die reinforcing platforms, and the one ends of the die reinforcing bosses are flush with the upper edges of the two sides of the bottom plate; the die cover plate is connected with the bottom plate of the die body, and covers the parts; the application further discloses a hydraulic forming method for M-shaped airplane longitudinal profile parts; and the application has the advantages of improving the processing efficiency and improving the forming quality.

Description

Technical Field

[0001] This invention belongs to the field of cold process sheet metal forming technology, specifically, it relates to a forming mold and a hydroforming method for M-shaped aircraft longitudinal profile parts. Background Technology

[0002] like Figure 1 The image shows a longitudinal profile part for a certain type of aircraft. The raw material for this part is a certain type of aerospace aluminum. Its prominent external features are a large slope on both sides of the curved edge, hooked edges, a relatively long longitudinal dimension, and an M-shaped cross-section (e.g., ...). Figure 2 (As shown). The traditional forming method for this type of part, according to the requirements of Q / 5A 2239-2017 "Sheet Metal Profiles," employs a manual forming method, where a hand-held hammer is used to gradually shape the blank until it fits snugly against the mold. However, this traditional forming method leaves numerous hammer marks on the part's surface, is time-consuming and labor-intensive, and has extremely low production efficiency. In particular, the severe deformation caused by heat treatment leads to a significant increase in correction work, resulting in poor surface quality after correction. Furthermore, due to the large slope of the bends on both sides, the material naturally flows downhill during forming, making it difficult to maintain the part's shape and easily leading to its scrapping.

[0003] Therefore, in order to overcome the difficulties of forming longitudinal profile parts of a certain type of aircraft, such as difficulty, long time consumption, and out-of-tolerance shape, this invention urgently needs to solve the problem of providing a forming mold and a hydraulic forming method for M-shaped longitudinal profile parts of aircraft that can improve processing efficiency, part qualification rate, and ensure part shape. Summary of the Invention

[0004] In view of the above-mentioned prior art, the purpose of this invention is to overcome the shortcomings of the prior art, adapt to the needs of reality, and thus provide a forming mold and a hydroforming method for M-shaped aircraft longitudinal profile parts that can improve processing efficiency, part qualification rate and ensure part shape.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a forming mold, comprising a mold body and a mold cover plate, wherein the mold body includes a base plate, mold reinforcing bosses and mold reinforcing platforms, and multiple mold reinforcing platforms are provided, respectively located on both sides of the base plate. Multiple mold reinforcing platforms are evenly distributed on one side of the base plate, and one mold reinforcing platform is provided on the other side, and the mold reinforcing platforms on both sides of the base plate are correspondingly arranged; multiple mold reinforcing bosses are provided, each respectively located on the mold reinforcing platform, and one end of each boss is flush with the upper edge of both sides of the base plate; the mold cover plate is connected to the base plate of the mold body, and the mold cover plate covers the part.

[0006] Furthermore, the base plate is a V-shaped long plate, and its structural shape and size match the structural shape and size of the V-shaped bend of the part.

[0007] Furthermore, the mold reinforcing platform has a convex shape, with its bottom flush with the bottom of both sides of the base plate and inclined relative to the horizontal plane. The inclination angle is consistent with the inclination angle of the V-shaped long plate on one side of the base plate. The mold reinforcing boss is a hollow trapezoidal body. The height of the trapezoidal body gradually increases from the end flush with the upper edges of both sides of the base plate to the end away from the upper edges of both sides of the base plate. The end flush with the upper edges of both sides of the base plate is the opening end of the hollow structure of the mold reinforcing boss. The mold reinforcing boss is located in the middle of the mold reinforcing platform.

[0008] Furthermore, the mold cover plate has a rectangular bottom and a triangular top, and the shape and size of the triangular top match the shape and size of the bottom plate of the mold body. Mold positioning pins are provided at both ends of the top of the mold cover plate, and the mold cover plate is fixedly connected to the bottom plate of the mold body through the mold positioning pins.

[0009] A hydroforming method for M-shaped aircraft longitudinal profile parts using the forming mold described above. This forming method is suitable for M-shaped aircraft longitudinal profile parts with a structure featuring large slopes on both sides, hooked edges, a long longitudinal dimension, and an M-shaped cross-section. The forming method includes:

[0010] The first step is to use digital means and CATIA 3D software to improve the 3D part model and process forming scheme according to the requirements. At each part notch, a process lug is added. Using CATIA software, the material neutral layer of the 3D part model is extracted to obtain the required CNC unfolding material.

[0011] The second step is to restrict the material from flowing to the lower slope, to ensure the shape of the parts and improve production efficiency. The forming mold is modified and optimized. The non-working surface of the forming mold is rounded to protect the machine tool rubber bladder. The bottom plate of the mold body fits with the parts. The mold cover plate covers the parts. The mold is reinforced and a small plane is milled out and a pin hole is opened.

[0012] The third step is to add bending pre-forming. Based on the part's digital model or template and combined with the neutral layer characteristics of the material, the bending line is calculated using digital means. The bending line is drawn on the CNC unfolded material obtained in the first step, and bending is performed to achieve pre-forming and obtain a part with a V-shaped bend.

[0013] The fourth step is to place the pre-formed V-shaped part obtained in the third step onto the mold body, and make the position of the process ear on the part correspond to the position of the mold reinforcing boss. Then, use a drill bit to pass through the pin hole at the bottom of the mold reinforcing boss upward until a punch point is made on the process ear, thereby forming two opposite small bends and opening holes. At this time, the part has a V-shaped bend and two opposite small bends.

[0014] The fifth step is to place the mold body on the worktable of the rubber bladder hydraulic press, then fix the parts obtained in the fourth step onto the mold body, cover it with the mold cover plate and rubber, and then perform hydraulic forming.

[0015] The sixth step, after the hydraulic forming in the fifth step is completed, is to trim the process ear pieces and perform local corrections to obtain the M-shaped aircraft longitudinal profile part.

[0016] Furthermore, CNC unfolded material refers to raw material cut by CNC machine tools.

[0017] Furthermore, the fillet radius of the non-working surface of the forming mold is 8mm.

[0018] Furthermore, the pin hole is a through hole and is located at the bottom of the mold reinforcing boss.

[0019] The beneficial effects of this invention are as follows: 1. Improved processing efficiency. Before using this forming method, the traditional forming method for this type of part was manual forming, that is, gradually shaping the blank with a hammer until it fits tightly against the mold; in particular, the parts undergo severe deformation after heat treatment, resulting in a significant increase in the amount of correction, which often consumes a lot of forming and correction time and physical labor. Actual production testing has proven that after adopting this forming method, the part fully meets the design requirements, and the operation is both time-saving and labor-saving for workers, and the production efficiency is greatly improved.

[0020] 2. Improved forming quality. Before using this forming method, traditional forming methods left numerous hammer marks on the surface of parts. The parts underwent severe deformation during heat treatment, leading to a significant increase in correction work and poor surface quality after correction. Furthermore, due to the large bends on both sides, material naturally flows downhill during forming, making it difficult to maintain the part's shape and easily resulting in scrap. After using this forming method, the shape accuracy of parts is significantly improved, and the inspection pass rate soars, providing a new solution for forming longitudinal profile parts for aircraft. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the longitudinal profile-type parts for M-shaped aircraft in the prior art;

[0022] Figure 2 for Figure 1 A schematic diagram of the cross-section;

[0023] Figure 3 This is a schematic diagram of the CNC unfolding and bending of the material according to the present invention;

[0024] Figure 4 This is a partial schematic diagram of the forming mold body of the present invention;

[0025] Figure 5 This is a schematic diagram of the hydroforming process of the present invention;

[0026] Figure 6 This is a schematic diagram of the structure of the mold cover plate of the present invention;

[0027] Figure 7 This is a schematic diagram of the forming mold of the present invention.

[0028] Wherein: 1 is the pin hole, 2 is the mold reinforcing boss, 3 is the mold reinforcing platform, 4 is the mold body, 5 is the mold cover plate, 6 is the part, 7 is the process ear, 8 is the CNC unfolded material, 9 is the part notch, 10 is the V-shaped bend, 11 is the opposite small bend, 12 is the mold positioning pin, and 13 is the base plate. Detailed Implementation

[0029] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0030] like Figures 4 to 7 As shown, the present invention provides a forming mold, including a mold body 4 and a mold cover plate 5. The mold body 4 includes a base plate 13, mold reinforcing bosses 2 and mold reinforcing platforms 3. Multiple mold reinforcing platforms 3 are provided and are respectively located on both sides of the base plate 13. Multiple mold reinforcing platforms 3 are evenly distributed on one side of the base plate 13 and one mold reinforcing platform 3 is provided on the other side. The mold reinforcing platforms 3 on both sides of the base plate 13 are correspondingly arranged. Multiple mold reinforcing bosses 2 are provided and are respectively provided on the mold reinforcing platforms 3. One end of each boss is flush with the upper edge of both sides of the base plate 13. The mold cover plate 5 is connected to the base plate 13 of the mold body 4 and covers the part 6.

[0031] Preferably, the base plate 13 is a V-shaped long plate, and its structural shape and size match the structural shape and size of the V-shaped bend 10 of the part 6.

[0032] Preferably, the mold reinforcing platform 3 has a convex shape, with its bottom flush with the bottom of both sides of the base plate 13 and inclined relative to the horizontal plane. The inclination angle is consistent with the inclination angle of the V-shaped long plate on one side of the base plate. The mold reinforcing boss 2 is a hollow trapezoidal body. The height of the trapezoidal body gradually increases from the end flush with the upper edge of both sides of the base plate 13 to the end away from the upper edge of both sides of the base plate 13. The end flush with the upper edge of both sides of the base plate 13 is the opening end of the hollow structure of the mold reinforcing boss 2. The mold reinforcing boss 2 is located in the middle of the mold reinforcing platform 3.

[0033] Preferably, the mold cover plate 5 has a rectangular bottom and a triangular top, and the shape and size of the triangular top match the shape and size of the base plate 13 of the mold body 4. Mold positioning pins 12 are provided at both ends of the top of the mold cover plate 5, and the mold cover plate 5 is fixedly connected to the base plate 13 of the mold body 4 through the mold positioning pins 12.

[0034] like Figures 1 to 7 As shown, the present invention also provides a hydroforming method for M-shaped aircraft longitudinal profile parts using the forming mold described above. This forming method is suitable for M-shaped aircraft longitudinal profile parts with a structure having large slopes on both sides, hooked edges, a long longitudinal dimension, and an M-shaped cross-section. The forming method includes:

[0035] The first step involves using digital methods and CATIA 3D software to improve the design based on the 3D part model and process forming scheme requirements, addressing the nine notches on each part (e.g., ...). Figure 2 As shown), add a process lug 7 to each part, and use CATIA software to extract the neutral material layer of the 3D model of the part to obtain the required CNC unfolded material 8, as shown. Figure 3 As shown;

[0036] The second step involves modifying and optimizing the forming mold to limit material flow towards the lower slope, ensuring the part's shape and improving production efficiency. The non-working surfaces of the forming mold are rounded to protect the machine tool's rubber bladder. The base plate 13 of the mold body 4 mates with the part 6, and the mold cover plate 5 covers the part 6. Figure 5 As shown, a small plane is milled out on the mold reinforcing table 3 and a pin hole 1 is drilled, as follows. Figure 4 As shown;

[0037] The third step involves adding pre-forming bending. Based on the part's digital model or template, and considering the neutral layer characteristics of the material, the bending line is calculated digitally. This bending line is then drawn on the CNC unfolded material 8 obtained in the first step, and bending is performed to achieve pre-forming, resulting in part 6 with a V-shaped bend 10. Figure 3 As shown;

[0038] Step four, as Figure 5 As shown, the part 6 with a V-shaped bend 10 obtained in the third step is placed on the mold body 4, and the position of the process lug 7 on the part 6 corresponds to the position of the mold reinforcing boss 2. Then, a drill bit is used to drill from the part 6. Figure 4 The pin hole 1 at the bottom of the mold reinforcing boss 2, as shown, extends upwards until it reaches the... Figure 3 The process ear piece 7 shown is punched with a punch point, which then forms two opposite small bends 11 and opens a hole. At this time, part 6 has a V-shaped bend 10 and two opposite small bends 11.

[0039] Fifth step, as Figure 5 As shown, the mold body 4 is placed on the worktable of the rubber bladder hydraulic press, and the part 6 obtained in the fourth step is fixed on the mold body 4. The mold cover plate 5 and the rubber are then covered and hydraulic forming is performed.

[0040] Step 6: After the hydraulic forming in step 5 is completed, trim the process ear piece 7 and perform local correction to obtain the M-shaped aircraft longitudinal profile part.

[0041] Preferably, the CNC unfolded material 8 is a rough material cut by a CNC machine tool.

[0042] Preferably, the fillet radius of the non-working surface of the forming mold is 8mm.

[0043] Preferably, the pin hole 1 is a through hole and is located at the bottom of the mold reinforcing boss 2.

[0044] As described above, changing the part forming method from manual forming to rubber bladder hydroforming significantly improved production efficiency, reduced residual stress during forming, and prevented severe deformation during heat treatment. After adopting this forming method, the prototype part achieved the expected results, with both its shape and surface quality meeting design requirements. It also significantly reduced manual workload and worker fatigue. Only localized correction was required after rubber bladder hydroforming, ensuring the surface quality of the part. Ultimately, the part forming objective was successfully achieved, and this method provides valuable reference and inspiration for the forming of similar parts.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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.

[0046] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of the invention and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A hydroforming method for M-shaped aircraft longitudinal profile parts using a forming mold, the forming method being suitable for M-shaped aircraft longitudinal profile parts with a structure having large slopes on both sides, hooked edges, a long longitudinal dimension, and an M-shaped cross-section, wherein the forming mold includes a mold body and a mold cover plate, wherein, The mold body includes a base plate, mold reinforcing bosses, and mold reinforcing platforms. Multiple mold reinforcing platforms are located on both sides of the base plate, with multiple platforms evenly distributed on one side and one platform on the other side. The mold reinforcing platforms on both sides of the base plate are correspondingly arranged. Multiple mold reinforcing bosses are also provided on the mold reinforcing platforms, with one end of each boss flush with the upper edge of both sides of the base plate. A mold cover plate is connected to the base plate of the mold body and covers the part. The forming method includes: The first step is to use digital means and CATIA 3D software to improve the 3D part model and process forming scheme according to the requirements. At each part notch, a process lug is added. Using CATIA software, the material neutral layer of the 3D part model is extracted to obtain the required CNC unfolding material. The second step is to restrict the material from flowing to the lower slope, to ensure the shape of the parts and improve production efficiency. The forming mold is modified and optimized. The non-working surface of the forming mold is rounded to protect the machine tool rubber bladder. The bottom plate of the mold body fits with the parts. The mold cover plate covers the parts. The mold is reinforced and a small plane is milled out and a pin hole is opened. The third step is to add bending pre-forming. Based on the part's digital model or template and combined with the neutral layer characteristics of the material, the bending line is calculated using digital means. The bending line is drawn on the CNC unfolded material obtained in the first step, and bending is performed to achieve pre-forming and obtain a part with a V-shaped bend. The fourth step is to place the pre-formed V-shaped part obtained in the third step onto the mold body, and make the position of the process ear on the part correspond to the position of the mold reinforcing boss. Then, use a drill bit to pass through the pin hole at the bottom of the mold reinforcing boss upward until a punch point is made on the process ear, thereby forming two opposite small bends and opening holes. At this time, the part has a V-shaped bend and two opposite small bends. The fifth step is to place the mold body on the worktable of the rubber bladder hydraulic press, then fix the parts obtained in the fourth step onto the mold body, cover it with the mold cover plate and rubber, and then perform hydraulic forming. The sixth step, after the hydraulic forming in the fifth step is completed, is to trim the process ear pieces and perform local corrections to obtain the M-shaped aircraft longitudinal profile part.

2. The hydroforming method for M-shaped aircraft longitudinal profile parts according to claim 1, characterized in that: The base plate is a V-shaped long plate, and its structural shape and size match the structural shape and size of the V-shaped bend of the part.

3. The hydroforming method for M-shaped aircraft longitudinal profile parts according to claim 1, characterized in that: The mold reinforcing platform has a convex shape, with its bottom flush with the bottom of both sides of the base plate and inclined relative to the horizontal plane. The inclination angle is the same as the inclination angle of the V-shaped long plate on one side of the base plate. The mold reinforcing boss is a hollow trapezoidal body. The height of the trapezoidal body gradually increases from the end flush with the upper edge of both sides of the base plate to the end away from the upper edge of both sides of the base plate. The end flush with the upper edge of both sides of the base plate is the opening end of the hollow structure of the mold reinforcing boss. The mold reinforcing boss is located in the middle of the mold reinforcing platform.

4. The hydroforming method for M-shaped aircraft longitudinal profile parts according to claim 1, characterized in that: The mold cover plate has a rectangular bottom and a triangular top. The shape and size of the triangular top match the shape and size of the base plate of the mold body. Mold positioning pins are provided at both ends of the top of the mold cover plate, and the mold cover plate is fixedly connected to the base plate of the mold body through the mold positioning pins.

5. The hydroforming method for M-shaped aircraft longitudinal profile parts according to claim 1, characterized in that: CNC unwrapped material refers to raw material cut by CNC machine tools.

6. The hydroforming method for M-shaped aircraft longitudinal profile parts according to claim 1, characterized in that: The fillet radius of the non-working surface of the forming mold is 8mm.

7. The hydroforming method for M-shaped aircraft longitudinal profile parts according to claim 1, characterized in that: The pin hole is a through hole and is located at the bottom of the mold reinforcing boss.

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