A multi-way draw whole-part forming die and method for a part including a closed angle feature

Abstract

This invention relates to the field of forming and manufacturing technology for thin-walled metal components in aerospace, shipbuilding, and rail transportation equipment, and particularly to an integral forming mold and method for parts with multi-directional curved edges and closed-angle features. Its features include an upper mold, a lower mold, a main support base for the lower mold, and a secondary support base for the lower mold. The lower mold consists of a side lower mold and a main lower mold, mounted on the main support base and the secondary support base. A main sliding rod is provided below the main lower mold, with a spring correspondingly installed at its lower end. A secondary sliding rod is provided below the secondary support base, and lower mold limiting blocks are provided on both sides of the lower mold. It employs a two-step forming method and a modular mold design to achieve integral forming of complex parts with multi-directional curved edges and closed-angle features. Furthermore, the device and operation method of this invention are safe and reliable, further reducing the labor intensity of workers and enabling continuous mass production.

Description

Technical Field

[0001] This invention relates to the field of forming and manufacturing technology of thin-walled metal components for aerospace, shipbuilding, rail transportation and other equipment, and particularly to an integral forming mold and method for a part with multi-directional curved edges including closed angle features. Background Technology

[0002] Thin-walled metal components are widely used in aerospace, shipbuilding, and rail transportation due to their lightweight, high strength, and good formability. However, with the increasing complexity of various equipment designs, the structural designs of parts are also becoming more complex, often including complex parts with multi-directional bends and closed-angle features. For such parts, traditional forming processes face numerous technical challenges and limitations in terms of precision, quality, cycle time, and number of processes. Traditional processes typically include: 1) Stamping: A process in which pressure is applied to a thin metal sheet using a die to induce plastic deformation and obtain the desired shape. For parts with multi-directional bends and closed angles, it is usually necessary to break the part down into smaller, easily formable parts without closed angles, and then assemble these smaller parts into the final part through other processes. This process is characterized by: a large number of dies, high die manufacturing costs and long cycles; low material utilization, with a large amount of waste generated during stamping (such as burrs, edge scraps, etc.), especially for complex-shaped parts; numerous forming steps, including many joining (welding, mechanical connections, etc.) and heat treatment processes, resulting in long manufacturing cycles and difficulty in controlling precision, leading to the inability to achieve the geometric accuracy required by the design.

[0003] 2) Stretch forming: A process in which a thin metal sheet is stretched using a die to achieve the desired shape. For parts with multi-directional bends and closed angles, additional forming dies or equipment are required to achieve the final shape, resulting in low production efficiency. Deformation uniformity is poor; in closed angle regions, the flow of metal material is uneven, easily leading to uneven thickness distribution and stress concentration, affecting the strength and durability of the parts. Equipment investment is high; stretch forming requires specialized equipment (such as stretching machines), and frequent die changes increase equipment maintenance and operating costs.

[0004] 3) Bending Forming: A process in which a thin metal sheet is bent using a punch press or bending machine to achieve the desired angle. For parts with multi-directional bends and closed-angle features, multiple clamping and die position adjustments are usually required. Furthermore, due to the closed-angle characteristics, the formed part is difficult to remove from the die. Precision control is challenging; when bending in multiple directions, each operation requires precise alignment of the workpiece, but due to the influence of material elastic deformation, the final geometric accuracy of the part is difficult to guarantee.

[0005] In summary, the above methods share the following common problems: low material utilization; whether stamping, stretching, or bending, traditional forming methods generate a large amount of waste when handling multi-directional bends and closed-angle features, leading to material waste. Frequent mold changes; due to the complex structure of the parts, multiple molds need to be designed or their positions adjusted, increasing production preparation time and costs. Low production efficiency; traditional processes typically require multiple clamping, adjustment, and forming operations, making it difficult to achieve efficient mass production. Insufficient precision and stability; in multi-directional bending and closed-angle regions, material flow and stress distribution are difficult to control, resulting in unstable part dimensions and compromised geometric accuracy.

[0006] For complex parts with multi-directional curved edges and closed angles in thin-walled metal components, traditional forming methods, while able to meet basic shape requirements, have significant shortcomings in mold design, production efficiency, material utilization, and precision control. To meet the demands of modern industry for high quality, high efficiency, and low cost, it is necessary to explore innovative mold structure designs and forming processes to overcome the limitations of traditional methods. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art by providing a part integral forming mold and method with multi-directional bending edge including closed angle features. This mold combines the elastic-plastic deformation characteristics of metal and comprehensively considers structural features such as multi-directional bending edge and closed angle, so as to achieve high-quality integral forming of the part.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A multi-directional curved edge integral forming mold with closed angle features includes an upper mold, a lower mold, a lower mold main support base, and a lower mold secondary support base. The lower mold consists of a side lower mold and a main lower mold. The lower mold is mounted on the lower mold main support base and the lower mold secondary support base. The main lower mold is mounted on the top of the lower mold main support base, and the side lower molds are mounted on the lower mold secondary support base. A lower mold main slide rod is provided below the main lower mold, and a spring is correspondingly provided at the lower end of the lower mold main slide rod. The upper end of the lower mold main slide rod passes through the lower mold main support base and connects to the main lower mold. A lower mold secondary slide rod is provided below the lower mold secondary support base, and lower mold limiting blocks are provided on both sides of the lower mold.

[0009] Furthermore, the lower surface of the upper mold matches the upper shape of the preformed part; the upper surface of the lower mold matches the lower shape of the preformed part; the lower mold limiting block matches the side shape of the preformed part; the overall fit of the lower surface of the upper mold, the upper surface of the lower mold, and the inner surface of the lower mold limiting block is ≥98%, with a maximum local gap ≤0.03mm, ensuring controllable springback and stable dimensional accuracy of the formed part. The lower surface of the upper mold, the upper surface of the lower mold, and the lower mold limiting block are all fully fitted with the theoretical digital model of the part using a conjugate coupling, without additional draft angle or gap compensation; a gap is provided between the upper mold and the lower mold limiting block for forming the internal bending closed angle feature of the part, and the gap dimension D is designed according to the following formula: D = L + (1.2 ~ 1.5)R D is the gap between the upper and lower mold limiting blocks, L is the projected length of the inner bend closed angle feature of the part relative to the side wall of the part, and R is the radius of the inner bend closed angle.

[0010] Furthermore, the side lower mold includes left and right lower molds, which are installed on both sides of the lower part of the main lower mold. The side lower mold and the main lower mold are assembled to form the lower mold. The side lower mold has a wedge-shaped structure and is provided with a protrusion structure for forming the internal bending closed angle feature of the part.

[0011] The side lower mold is provided with a wedge-shaped surface, and a sliding boss is provided on the wedge-shaped surface. The lower mold main support base is provided with a wedge-shaped surface, and a sliding groove is provided on the wedge-shaped surface. The wedge-shaped surface on the side lower mold is installed on the wedge-shaped surface of the lower mold main support base. The sliding boss and the sliding groove cooperate to realize the movement of the side lower mold.

[0012] Furthermore, the clearance between the sliding boss and the sliding groove of the lower side mold is ≤0.015mm; the spring preload during clamping is set at 1.2 times the yield strength of the material to ensure no movement during the forming process; the surface roughness Ra of all working surfaces of the mold is ≤0.8μm to ensure the surface quality and dimensional consistency of the parts, while ensuring smooth relative movement of each part of the mold.

[0013] The lower mold main slide rod includes a slide rod and a sleeve. The sleeve moves up and down along the slide rod. The slide rod is fitted in a spring, and the spring supports the sleeve. The up and down movement of the lower mold main slide rod is achieved through the elastic deformation of the spring, which in turn drives the main lower mold to move up and down.

[0014] Furthermore, the lower mold auxiliary slide bar has the same structure as the lower mold main slide bar, and the lower end of the lower mold auxiliary slide bar is also provided with a spring for realizing the up and down movement of the lower mold auxiliary slide bar.

[0015] A method for integral forming of a part with a multi-directional curved edge including a closed angle feature, characterized by the following steps: Step 1: Place the preform on the lower mold of the integral forming mold of the multi-directional curved edge containing the closed angle feature. At this time, the lower mold is pushed upward under the action of spring force and is not in the final forming position. Step 2: Start mold closing. The upper mold moves towards the lower mold. When the upper mold contacts the preform placed in the lower mold, the main lower mold moves downward through the main slide rod of the lower mold under the action of the mold closing force of the upper mold. Step 3: When the main lower die moves downward, it drives the side lower dies to move downward; at the same time, due to the action of the wedge-shaped surface, the two lower dies are pushed out to both sides along the wedge-shaped surface respectively; Step 4: When the lower side mold moves downward, it drives the lower mold auxiliary support seat to move downward through the lower mold auxiliary slide rod, and at the same time compresses the spring outside the lower mold auxiliary slide rod; due to the action of the lower mold limiting block, the side wall of the preform always remains in its theoretical forming position; Step 5: When the main lower mold descends onto the main support seat of the lower mold, the upper mold and the main lower mold stop moving. At this time, the side lower molds move to their theoretical positions on both sides, pushing the inner curved closed angle feature out toward the preform. At this time, the upper mold and the lower mold limit blocks close to the theoretical position. Under the combined action of the total forming pressure between the upper mold and the lower mold limit blocks and the ejection force of the side lower molds, the inner curved closed angle feature is formed. Step 6: Lift the upper mold upwards, and the lower mold will be pushed upwards by the spring force to remove the formed part, thus completing the part forming process.

[0016] Furthermore, in step five, the total forming pressure between the upper mold and the lower mold limiting block is 1.5 to 2.0 times the tensile strength of the material, and the mold closing speed is 5 to 10 mm / s; the initial contact pressure when the upper mold and the lower mold limiting block close is 30% to 40% of the total forming pressure, and it is increased to the set total forming pressure value during the mold closing process, with a holding time of 15 to 30 seconds.

[0017] The beneficial effects of this invention are as follows: The integral forming mold and method for a multi-directional curved part with closed-angle features employs a two-step forming method and a modular mold design to achieve integral forming of complex parts with multi-directional curved edges and closed-angle features. Simultaneously, the device and operation method of this invention are safe and reliable, further reducing the labor intensity of workers, enabling continuous mass production. The mold-related structures can be made of different materials according to actual needs, achieving forming of different materials at high and low temperatures, ensuring that the final parts meet multiple requirements such as forming accuracy, surface quality, mechanical properties, and service performance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the component structure of the multi-directional curved edge of the present invention, which includes the closed angle feature. Figure 2 This is a schematic diagram of the preform structure of the multi-directional curved edge of the present invention, which includes the closed angle feature. Figure 3 This is a schematic diagram of the pre-forming assembly structure of the final forming mold of the present invention; Figure 4 This is a schematic diagram of the assembly structure of the final forming mold of the present invention during final forming; Figure 5 This is a schematic diagram of the lower mold structure of the final forming mold of the present invention; Figure 6 This is a schematic diagram of the main support structure of the lower mold of the present invention; Figure 7 This is a schematic diagram of the side lower mold structure of the present invention.

[0019] In the figure, 1. Preform; 2. Upper mold; 3. Lower mold; 3-1. Side lower mold; 3-1-1. Side lower mold wedge surface; 3-1-2. Side lower mold sliding boss; 3-2. Main lower mold; 4. Lower mold main support seat; 4-1. Lower mold main support seat wedge surface; 4-2. Lower mold main support seat sliding groove; 5. Lower mold main slide rod; 6. Lower mold secondary support seat; 7. Lower mold secondary slide rod; 8. Lower mold limiting block; 9. Spring; 10. Inner bend closed angle feature. Detailed Implementation

[0020] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0021] To achieve the above objectives, the present invention provides the following specific embodiments: like Figure 3-7 As shown, a multi-directional curved edge integral forming mold for a part with closed angle features includes an upper mold 2, a lower mold 3, a lower mold main support 4, and a lower mold secondary support 6. The lower mold 3 is composed of a side lower mold 3-1 and a main lower mold 3-2. The lower mold 3 is mounted on the lower mold main support 4 and the lower mold secondary support 6. The main lower mold 3-2 is mounted on the top of the lower mold main support 4, and the side lower mold 3-1 is mounted on the lower mold secondary support 6. A lower mold main slide rod 5 is provided below the main lower mold 3-2, and a spring 9 is correspondingly provided at the lower end of the lower mold main slide rod 5. The upper end of the lower mold main slide rod 5 passes through the lower mold main support 4 and connects to the main lower mold 3-2. A lower mold secondary slide rod 7 is provided below the lower mold secondary support 6, and lower mold limiting blocks 8 are provided on both sides of the lower mold 3.

[0022] Furthermore, the lower surface of the upper mold 2 matches the upper shape of the preform 1; the upper surface of the lower mold 3 matches the lower shape of the preform 1; the lower mold limiting block 8 matches the side shape of the preform 1; the overall fit of the lower surface of the upper mold 2, the upper surface of the lower mold 3, and the inner surface of the lower mold limiting block 8 is ≥98%, with a maximum local gap ≤0.03mm, ensuring controllable springback and stable dimensional accuracy of the formed part. The lower surface of the upper mold 2, the upper surface of the lower mold 3, and the lower mold limiting block 8 are all fully fitted with the theoretical digital model of the part using a conjugate coupling, without additional draft angle or gap compensation; a gap is provided between the upper mold 2 and the lower mold limiting block 8 for forming the inner bending closed angle feature 10 of the part, and the gap dimension D is designed according to the following formula: D = L + (1.2 ~ 1.5)R D is the gap between the upper and lower mold limiting blocks, L is the projected length of the inner bend closed angle feature of the part relative to the side wall of the part, and R is the radius of the inner bend closed angle.

[0023] Furthermore, the side lower mold 3-1 includes left and right lower molds, which are installed on both sides of the lower part of the main lower mold 3-2. After the side lower mold 3-1 and the main lower mold 3-2 are assembled, the lower mold 3 is formed. The side lower mold 3-1 has a wedge-shaped structure, and a protrusion structure is provided on the side lower mold 3-1 for forming the inner bending closed angle feature 10 of the part.

[0024] The lower side mold 3-1 is provided with a wedge-shaped surface 3-1-1, and a sliding boss 3-1-2 is provided on the wedge-shaped surface 3-1-1. The lower mold main support 4 is provided with a wedge-shaped surface 4-1, and a sliding groove 4-2 is provided on the wedge-shaped surface 4-1. The wedge-shaped surface 3-1-1 on the lower side mold 3-1 is installed on the wedge-shaped surface 4-1 of the lower mold main support 4. The sliding boss 3-1-2 cooperates with the sliding groove 4-2 to realize the movement of the lower side mold 3-1.

[0025] Furthermore, the clearance between the sliding boss 3-1-2 of the side lower mold 3-1 and the sliding groove 4-2 is ≤0.015mm; the preload of the spring 9 during clamping is set at 1.2 times the yield strength of the material to ensure no movement during the forming process; the surface roughness Ra of all mold working surfaces is ≤0.8μm to ensure the surface quality and dimensional consistency of the parts, while ensuring smooth relative movement of each part of the mold.

[0026] The lower mold main slide rod 5 includes a slide rod and a sleeve. The sleeve moves up and down along the slide rod. The slide rod is fitted in the spring 9. The spring 9 supports the sleeve. The lower mold main slide rod 5 moves up and down through the elastic deformation of the spring 9, which in turn drives the main lower mold 3-2 to move up and down.

[0027] Furthermore, the lower mold auxiliary slide rod 7 has the same structure as the lower mold main slide rod 5, and the lower end of the lower mold auxiliary slide rod 7 is also provided with a spring for realizing the up and down movement of the lower mold auxiliary slide rod 7.

[0028] A method for integral forming of a part with a multi-directional curved edge including a closed angle feature, such as... Figure 1-7 As shown, its characteristic includes the following steps: Step 1: Place the preform 1 on the lower mold 3 of the integral forming mold of the part with multi-directional curved edge containing closed angle features. At this time, the lower mold 3 is pushed upward under the action of spring force and is not in the final forming position. Step 2: Start mold closing. The upper mold 2 moves towards the lower mold 3. When the upper mold 2 contacts the preform 1 placed in the lower mold 3, the main lower mold 3-2 moves downward through the main slide bar 5 of the lower mold under the action of the mold closing force of the upper mold 2. Step 3: When the main lower die 3-2 moves downward, it drives the side lower die 3-1 to move downward; at the same time, due to the action of the wedge surface 3-1-1, the two lower dies 3-1 are pushed out to both sides along the wedge surface 3-1-1 respectively. Step 4: When the lower side mold 3-1 moves downward, it drives the lower mold auxiliary support 6 to move downward through the lower mold auxiliary slide rod 7, and at the same time compresses the spring 9 outside the lower mold auxiliary slide rod 7; due to the action of the lower mold limiting block 8, the side wall of the preform 1 always remains in its theoretical forming position. Step 5: When the main lower mold 3-2 descends onto the main support seat 4 of the lower mold, the upper mold 2 and the main lower mold 3-2 stop moving. At this time, the side lower mold 3-1 moves to the theoretical position on both sides, pushing the inner curved closed angle feature 10 out toward the preform 1. At this time, the upper mold 2 and the lower mold limiting block 8 close to the theoretical position. Under the combined action of the total forming pressure between the upper mold 2 and the lower mold limiting block 8 and the ejection force of the side lower mold 3-1, the inner curved closed angle feature 10 is formed. Step 6: Lift the upper mold 2 upwards, and the lower mold 3 will be pushed upwards under the action of the spring force to remove the formed part, thus completing the forming of the part.

[0029] Furthermore, in step five, the total forming pressure between the upper mold 2 and the lower mold limiting block 8 is 1.5 to 2.0 times the tensile strength of the material, and the mold closing speed is 5 to 10 mm / s; the initial contact pressure when the upper mold 2 and the lower mold limiting block 8 close is 30% to 40% of the total forming pressure, and it is increased to the set total forming pressure value during the mold closing process, with a holding time of 15 to 30 seconds.

[0030] Furthermore, for a multi-directional curved edge part integral forming mold with positioning and assembly requirements among its components, locating pins, guide pillars, and other structures can be used for assembly and positioning. The coaxiality tolerance of the locating pins / guide pillars and their locating holes / guide holes is ≤0.02mm.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A mold for integral forming of a part with a multi-directional curved edge including a closed angle feature, characterized in that, Includes upper mold, lower mold, lower mold main support base, and lower mold auxiliary support base; The lower mold consists of a side lower mold and a main lower mold, and the lower mold is installed on the lower mold main support base and the lower mold auxiliary support base; The main lower mold is installed on the top of the main support seat of the lower mold, and the side lower mold is installed on the auxiliary support seat of the lower mold. A lower mold main slide rod is provided below the main mold, and a spring is provided at the lower end of the lower mold main slide rod. The upper end of the lower mold main slide rod passes through the lower mold main support base and is connected to the main lower mold. A lower mold auxiliary slide rod is provided below the lower mold auxiliary support base, and lower mold limiting blocks are provided on both sides of the lower mold.

2. The integral forming mold for a part with a multi-directional curved edge including a closed angle feature as described in claim 1, characterized in that, The lower surface of the upper mold matches the upper shape of the preformed part; the upper surface of the lower mold matches the lower shape of the preformed part. The lower mold limiting block matches the side profile of the preformed part; the overall fit of the lower mold surface, the upper mold surface, and the inner surface of the lower mold limiting block is ≥98%, and the maximum local gap is ≤0.03mm; A gap is provided between the upper die and the lower die limiting block to form the inward bending closed angle feature of the part. The gap dimension D is designed according to the following formula: D = L + (1.2 ~ 1.5)R, D is the gap between the upper and lower mold limiting blocks, L is the projected length of the inner bend closed angle feature of the part relative to the side wall of the part, and R is the radius of the inner bend closed angle.

3. The integral forming mold for a part with a multi-directional curved edge including a closed angle feature as described in claim 1, characterized in that, The side lower mold includes left and right lower molds, which are installed on both sides of the lower part of the main lower mold. The side lower mold and the main lower mold are assembled to form the lower mold. The side lower mold has a wedge-shaped structure and is provided with a protrusion structure for forming the internal bending closed angle feature of the part.

4. The integral forming mold for a part with a multi-directional curved edge including a closed angle feature as described in claim 1, characterized in that, The lower side mold is provided with a wedge-shaped surface, and a sliding boss is provided on the wedge-shaped surface. The main support base of the lower mold is provided with a wedge-shaped surface, and a sliding groove is provided on the wedge-shaped surface. The wedge-shaped surface on the lower side mold is installed on the wedge-shaped surface of the main support base of the lower mold. The sliding boss and the sliding groove cooperate to realize the movement of the lower side mold.

5. The integral forming mold for a part with a multi-directional curved edge including a closed angle feature as described in claim 4, characterized in that, The clearance between the sliding boss and the sliding groove of the lower side mold is ≤0.015mm; the spring preload is set at 1.2 times the yield strength of the material during clamping to ensure no movement during the forming process; the surface roughness Ra of all working surfaces of the mold is ≤0.8μm to ensure the surface quality and dimensional consistency of the parts, while ensuring smooth relative movement of each part of the mold.

6. The integral forming mold for a part with a multi-directional curved edge including a closed angle feature as described in claim 1, characterized in that, The lower mold main slide rod includes a slide rod and a sleeve. The sleeve moves up and down along the slide rod. The slide rod is fitted in a spring, and the spring supports the sleeve. The up and down movement of the lower mold main slide rod is achieved through the elastic deformation of the spring, which in turn drives the main lower mold to move up and down.

7. The integral forming mold for a part with a multi-directional curved edge including a closed angle feature as described in claim 1, characterized in that, The lower mold auxiliary slide rod has the same structure as the lower mold main slide rod, and a spring is also provided at the lower end of the lower mold auxiliary slide rod to realize the up and down movement of the lower mold auxiliary slide rod.

8. A method for integral forming of a part using an integral forming mold for a multi-directional bent edge comprising a closed angle feature as described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Place the preform on the lower mold of the integral forming mold of the multi-directional curved edge containing the closed angle feature. At this time, the lower mold is pushed upward under the action of spring force and is not in the final forming position. Step 2: Start mold closing. The upper mold moves towards the lower mold. When the upper mold contacts the preform placed in the lower mold, the main lower mold moves downward through the main slide rod of the lower mold under the action of the mold closing force of the upper mold. Step 3: When the main lower die moves downward, it drives the side lower dies to move downward; at the same time, due to the action of the wedge-shaped surface, the two lower dies are pushed out to both sides along the wedge-shaped surface respectively; Step 4: When the lower side mold moves downward, it drives the lower mold auxiliary support seat to move downward through the lower mold auxiliary slide rod, and at the same time compresses the spring outside the lower mold auxiliary slide rod; due to the action of the lower mold limiting block, the side wall of the preform always remains in its theoretical forming position; Step 5: When the main lower mold descends onto the main support seat of the lower mold, the upper mold and the main lower mold stop moving. At this time, the side lower molds move to their theoretical positions on both sides, pushing the inner curved closed angle feature out toward the preform. At this time, the upper mold and the lower mold limit blocks close to the theoretical position. Under the combined action of the total forming pressure between the upper mold and the lower mold limit blocks and the ejection force of the side lower molds, the inner curved closed angle feature is formed. Step 6: Lift the upper mold upwards, and the lower mold will be pushed upwards by the spring force to remove the formed part, thus completing the part forming process.

9. The integral forming method for a part with a multi-directional curved edge including a closed angle feature as described in claim 8, characterized in that, In step five, the total forming pressure between the upper mold and the lower mold limiting block is 1.5 to 2.0 times the tensile strength of the material, and the mold closing speed is 5 to 10 mm / s. The initial contact pressure when the upper mold and the lower mold limiting block close is 30% to 40% of the total forming pressure, which is increased to the set total forming pressure value during the mold closing process, and the pressure holding time is 15 to 30 seconds.

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