CURVED-SURFACE COMPONENT FORMING DEVICE AND CURVED-SURFACE COMPONENT FORMING METHOD

Description

CROSS-REFERENCE TO RELATED APPLICATION

This patent application claims the benefit and priority of Chinese Patent Application No. 2024115574820, entitled “CURVED-SURFACE COMPONENT FORMING DEVICE AND CURVED-SURFACE COMPONENT FORMING METHOD” filed on Nov. 2, 2024, the disclosure of which is incorporated by reference herein in its entirety as part of the present application.

TECHNICAL FIELD

The present disclosure relates to the field of sheet forming, and in particular to a curved-surface component forming device and a curved-surface component forming method.

BACKGROUND

Large-scale complex curved-shaped shells, as critical components in fields such as aviation, aerospace, maritime and nuclear fusion, have characteristics such as ultra-large dimensions and bidirectional variable curvature. The large-scale complex curved-surface shells have complex profiles and high dimensional accuracy requirements, making their manufacturing process a constant significant challenge. At present, the curved-surface component is mainly formed by rigid die pressing, including cold press forming and hot press forming. The cold press forming has characteristics of high production efficiency and long die service life, while hot pressing forming has characteristics of small springback and low forming load. However, the cold press forming has the defects of springback and wrinkling, while the hot press forming has high die cost and is prone to the deterioration of the microstructure and properties of the component, failing to meet the requirements for properties such as mechanical/magnetic performance. In addition, the conventional cold and hot press forming technologies are often difficult to meet the requirements of rapid and accurate forming, with prominent problems such as complex technical routes and long cycles.

To save the production cost and manufacturing cycle and improve the forming limit and dimensional accuracy, some rigid-flexible medium composite forming processes that replace part of the rigid dies with flexible media have emerged and developed, such as sheet fluid pressure forming, hot gas pressure forming, and rubber bladder forming. Flexible forming processes that use fluid media for forming basically all have sealing and medium leakage problems. Process sections and sealing sections must be added to form a closed cavity in a forming area, leading to problems such as low material utilization. Due to a large forming load required by a large-thickness component, a forming load capable of being applied by the forming media (fluid, gas and rubber bladder) in the foregoing three forming methods is limited, for example, the fluid pressure is generally less than 200 MPa, the gas pressure is generally less than 20 MPa and the rubber bladder pressure is generally less than 5 MPa. Therefore, the methods such as sheet fluid pressure forming, hot gas pressure forming and rubber bladder forming are only suitable for forming thin sheets, and cannot be applied to forming components with large thicknesses. For example, the thickness of a ship shell and the thickness of a nuclear fusion vacuum chamber shell reach several tens of millimeters, which cannot be formed by adopting the sheet fluid pressure forming, hot gas pressure forming and rubber bladder forming methods.

SUMMARY

The embodiments aim to provide a curved-surface component forming device and a curved-surface component forming method to solve the problems in the prior art. A large curved-surface shell component that meets the accuracy requirements can be obtained at low cost and high efficiency, the obtained curved-surface component has high contour accuracy and excellent surface quality, a press forming process of the curved-surface shell component can be greatly simplified, and material utilization is improved.

To achieve the objective described above, the present disclosure provides the following solutions.

The present disclosure provides a curved-surface component forming device, including a forming die and at least one elastic compensation pad. The forming die includes a male die device and a female die device. The male die device and the female die device are both rigid dies; or one of the male die devices and the female die device is the rigid die, and an other of the male die device and the female die device is an elastic die. An initial sheet blank is placed between the male die device and the female die device.

When the male die device and the female die device are both rigid dies, the at least one elastic compensation pad is arranged between the male die device and the initial sheet blank and/or between the female die device and the initial sheet blank. Each of the at least one elastic compensation pad is able to contact with partial surface of the initial sheet blank. By moving the male die device toward the female die device and/or moving the female die device toward the male die device, the at least one elastic compensation pad and the initial sheet blank are pressed against each other, and the initial sheet blank is formed into a curved-surface formed part.

When one of the male die device and the female die device is the rigid die and the other of the male die device and the female die device is the elastic die, by moving the male die device toward the female die device and/or moving the female die device toward the male die device, the initial sheet blank is formed into a curved-surface formed part.

Portions of the curved-surface formed part where a deviation of a contour dimension from a target curved-surface component exceed a specified value are surfaces to be compensated of the curved-surface formed part. The at least one elastic compensation pad is capable of being arranged between a working surface of the forming die and the surfaces to be compensated and is capable of contacting with the surfaces to be compensated.

In some embodiments, the elastic die includes at least one first elastic body. Multiple first elastic bodies are arranged in a stacked manner.

In some embodiments, each of the multiple first elastic bodies of the elastic die is flat-shaped. The initial sheet blank and the curved-surface formed part are both parts to be processed. From one side adjacent to a part to be processed to one side away from the part to be processed. Outer contour dimensions of the multiple first elastic bodies sequentially decrease. The elastic die is deformed into a convex shape or a concave shape by pressing against the part to be processed.

In some embodiments, the elastic die includes a curved-surface elastomer, and a working surface of the curved-surface elastomer is a convex curved-surface or a concave curved-surface.

In some embodiments, the elastic die includes a rigid male die and a second elastic body. The second elastic body is arranged between the rigid male die and the part to be processed. The second elastic body is deformed into a convex shape by pressing against the part to be processed.

The present disclosure provides a curved-surface component forming method based on the curved-surface component forming device, including:

• • S1, forming the initial sheet blank into the curved-surface formed part by adopting a first method or a second method, wherein:
  • the first method includes: configuring the male die device and the female die device both as rigid dies, arranging at least one elastic compensation pad between the male die device and the initial sheet blank and/or between the female die device and the initial sheet blank; moving the male die device toward the female die device and/or moving the female die device toward the male die device, enabling the elastic compensation pad and the initial sheet blank to press against each other, and forming the initial sheet blank into the curved-surface formed part;
  • the second method includes: configuring one of the male die device and the female die device as the rigid die and the other of the male die device and the female die device as the elastic die, moving the male die device toward the female die device and/or moving the female die device toward the male die device, and forming the initial sheet blank into the curved-surface formed part; and
  • S2: obtaining positions of the surfaces to be compensated on the curved-surface formed part, arranging the at least one elastic compensation pad on each of the surfaces to be compensated of the curved-surface component, and pressing the curved-surface formed part again by adopting the male die device and the female die device in the first method or the second method until the deviation between contour dimensions of the curved-surface formed part and the target curved-surface component is less than or equal to the specified value.

In some embodiments, S1 further includes: before pressing the initial sheet blank, obtaining a shape and a dimension of the initial sheet blank based on a shape and a dimension of the target curved-surface component.

In some embodiments, the elastic die includes at least one first elastic body, and multiple first elastic bodies are arranged in a stacked manner.

S1 further includes: before pressing the initial sheet blank, obtaining a material, a shape and a dimension of the elastic die based on the shape and the dimension of the target curved-surface component and the shape and the dimension of the initial sheet blank; determining a thickness of each of the multiple first elastic bodies, and obtaining a number of the multiple first elastic bodies according to a thickness of the elastic die and the thickness of each of the multiple first elastic bodies; and obtaining a stacking manner of the multiple first elastic bodies.

In some embodiments, S1 includes a method for obtaining the shape and the dimension of the initial sheet blank, including: obtaining a shape and a dimension of the initial sheet blank based on a shape of a developed blank corresponding to a developed target curved-surface component; increasing an outer contour dimension of the initial sheet blank by an allowance of 20 mm to 80 mm based on the dimension of the developed blank for the target curved-surface component, and enabling a thickness of the initial sheet blank to equal to a thickness of the target curved-surface component, or increasing the thickness of the initial sheet blank by an allowance of 0.1 mm to 8 mm based on the thickness of the target curved-surface component.

In some embodiments, S1 includes a method for obtaining the dimension of the elastic die, including: enabling the thickness of the elastic die to 1 to 2 times a maximum height of the target curved-surface component; obtaining a thickness of each of the multiple first elastic bodies, and obtaining a number of the multiple first elastic bodies based on the thickness of the elastic die and the thickness of each of the multiple first elastic bodies. A contour dimension of the elastic die is not less than a contour dimension of the initial sheet blank.

Compared with the prior art, the embodiments have the following technical effects.

The embodiments provide the curved-surface component forming device and the curved-surface component forming method. The device includes at least one elastic compensation pad, a male die device and a female die device are both rigid dies; or one of the male die device and the female die device is the rigid die, and the other of the male die device and the female die device is an elastic die; and an initial sheet blank is arranged between the male die device and the female die device. When the male die device and the female die device are both rigid dies, at least one elastic compensation pad is arranged between the male die device and the initial sheet blank and/or between the female die device and the initial sheet blank. By moving the male die device toward the female die device and/or moving the female die device toward the male die device, the elastic compensation pad and the initial sheet blank can be pressed against each other, and the initial sheet blank can be formed into a curved-surface formed part. When one of the male die device and the female die device is the rigid die and the other of the male die device and the female die device is the elastic die, by moving the male die device toward the female die device and/or moving the female die device toward the male die device, the initial sheet blank can be formed into a curved-surface formed part. A portion of the curved-surface formed part where a deviation of a contour dimension from a target curved-surface component exceeds a specified value is a surface to be compensated of the curved-surface formed part. The elastic compensation pad can be arranged between a working surface of the forming die and the surface to be compensated, and can contact with the surface to be compensated.

The above-mentioned curved-surface component forming device can obtain a curved-surface component meeting accuracy requirements at low cost and high efficiency, especially obtaining a large curved-surface shell component capable of meeting accuracy requirements at low cost and high efficiency, specifically as follows. (1) The male die device and the female die device together form a semi-closed die cavity, and the elastic die can deform and flow in the semi-closed die cavity, such that a same die assembly can adapt to the forming of sheet blanks with different thicknesses in a certain range, and the die has high flexibility. (2) When the male die device and the female die device are closed to press the initial sheet blank, the elastic die can contact with an upper surface or lower surface of the initial sheet blank, or the elastic compensation pad can contact with partial upper surface and/or lower surface of the initial sheet blank, such that the elastic die or elastic compensation pad interacts with the initial sheet blank, and the elastic die or elastic compensation pad is in a soft contact state with the initial sheet blank, which overcomes point contact loading of a conventional rigid die. A contact position enables near-uniform normal load application with surface-to-surface soft contact, which can effectively reduce a bending stress inside the initial sheet blank, reduce or eliminate wrinkling defects, significantly lower component spring-back, and improve processing quality. (3) The soft contact near-uniform load application between the elastic die and the initial sheet blank can effectively reduce or avoid scratches on the surface of the component and improve the surface quality. (4) After the initial sheet blank is processed into the curved-surface formed part, if the accuracy does not meet the requirement, local quantitative compensation can be performed on a die profile corresponding to the surface to be compensated by adopting the elastic compensation pad, a high-accuracy curved-surface shell component can be formed without or with minimal die repair. This can greatly reduce die repair time and cost, thereby shortening a manufacturing cycle and lowering the manufacturing cost. (5) In this embodiment, an elastomer (elastic die or elastic compensation pad) serves as a forming medium, the elastomer is a solid medium with a pressure bearing capacity much greater than that of a gas and fluid, and can bear a pressure greater than 200 MPa. The elastomers made of different materials can be replaced according to a forming load required by the formed part, which has stronger adaptability and wider application scope. (6) A process allowance of the initial sheet blank is very small, which, compared with conventional stretch forming and deep drawing processes, can significantly improve material utilization and reduce manufacturing cost.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the technical solutions in the embodiments of the present disclosure or in the prior art more clearly, the following briefly introduces the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description show merely some embodiments of the present disclosure, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

FIG. 1 is a structural diagram of a curved-surface component forming device according to Embodiment I;

FIG. 2 is a sectional diagram of the curved-surface component forming device according to Embodiment I;

FIG. 3 is a first structural diagram of a curved-surface component forming device according to Embodiment II;

FIG. 4 is a second structural diagram of the curved-surface component forming device according to Embodiment II;

FIG. 5 is a first structural diagram of a curved-surface component forming device according to Embodiment III;

FIG. 6 is a second structural diagram of the curved-surface component forming device according to Embodiment III;

FIG. 7 is a first structural diagram of a curved-surface component forming device according to Embodiment IV;

FIG. 8 is a second structural diagram of the curved-surface component forming device according to Embodiment IV;

FIG. 9 is a first structural diagram of a curved-surface component forming device applied in a first method according to Embodiment V;

FIG. 10 is a second structural diagram of the curved-surface component forming device applied in a first method according to Embodiment V;

FIG. 11 is a structural diagram of a target curved-surface component according to Embodiments I-V;

FIG. 12 is a first flowchart of a curved-surface component forming method according to Embodiment V;

FIG. 13 is a second flowchart of the curved-surface component forming method according to Embodiment V.

List of the reference characters: 100 curved-surface component forming device; 1 upper die plate; 2 male die device; 3 initial sheet blank; 4 female die device; 5 lower die plate; 6 rigid male die; 7 bolt; 8 steel wire rope; 9 target curved-surface component; 10 elastic compensation pad; 11 first elastic body; 12 curved-surface elastomer; 13 second elastic body.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following clearly and completely describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

The embodiments aim to provide a curved-surface component forming device and a curved-surface component forming method to solve the problems in the prior art. A large curved-surface shell component that meets the accuracy requirements can be obtained at low cost and high efficiency, the obtained curved-surface component has high contour accuracy and excellent surface quality, a press forming process of the curved-surface shell component can be greatly simplified, and material utilization is improved.

To make the foregoing objectives, features and advantages of the present disclosure more apparent and easier to understand, the present disclosure will be further described in detail with the accompanying drawings and specific implementations.

Embodiment I

As shown in FIG. 1 to FIG. 11, this embodiment provides a curved-surface component forming device 100, including a forming die and at least one elastic compensation pad 10. The forming die includes a male die device 2 and a female die device 4. The male die device 2 and the female die device 4 are both rigid dies; or one of the male die device 2 and the female die device 4 is the rigid die, and the other of the male die device 2 and the female die device 4 is an elastic die. An initial sheet blank 3 is placed between the male die device 2 and the female die device 4. When the male die device 2 and the female die device 4 are both rigid dies, at least one elastic compensation pad 10 is arranged between the male die device 2 and the initial sheet blank 3 and/or between the female die device 4 and the initial sheet blank 3, and each elastic compensation pad 10 is in contact with partial surface of the initial sheet blank 3. By moving the male die device 2 toward the female die device 4 and/or moving the female die device 4 toward the male die device 2, the elastic compensation pad 10 and the initial sheet blank 3 can be pressed against each other, and the initial sheet blank 3 can be formed into a curved-surface formed part. When one of the male die device 2 and the female die device 4 is the rigid die and the other of the male die device 2 and the female die device 4 is the elastic die, by moving the male die device 2 toward the female die device 4 and/or moving the female die device 4 toward the male die device 2, the initial sheet blank 3 can be formed into a curved-surface formed part. A portion of the curved-surface formed part where a deviation of a contour dimension from the target curved-surface component exceeds a specified value is a surface to be compensated of the curved-surface formed part. The elastic compensation pad 10 can be arranged between a working surface of the forming die and the surface to be compensated and contact with the surface to be compensated. When one of the male die device 2 and the female die device 4 is the rigid die and the other of the male die device 2 and the female die device 4 is the elastic die, a profile of the rigid die is configured to shape the initial sheet blank to ensure the processing accuracy.

The curved-surface component forming device 100 can obtain a curved-surface component meeting accuracy requirements at low cost and high efficiency, especially obtaining a large curved-surface shell component capable of meeting accuracy requirements at low cost and high efficiency. A press forming process of the curved-surface shell component can be greatly simplified, and material utilization is improved, specifically as follows. (1) The male die device 2 and the female die device 4 together form a semi-closed die cavity, and the elastic die can deform and flow in the semi-closed die cavity, such that a same die assembly can adapt to the forming of sheet blanks with different thicknesses in a certain range, and the die has high flexibility. (2) When the male die device 2 and the female die device 4 are closed to press the initial sheet blank 3, the elastic die can contact with an upper surface or lower surface of the initial sheet blank 3, or the elastic compensation pad 10 can contact with partial upper surface and/or lower surface of the initial sheet blank 3, such that the elastic die or elastic compensation pad 10 interacts with the initial sheet blank 3, and the elastic die or elastic compensation pad 10 is in a soft contact state with the initial sheet blank 3, which overcomes point contact loading of a conventional rigid die. A contact position enables near-uniform normal load application with surface-to-surface soft contact, which can effectively reduce a bending stress inside the initial sheet blank, reduce or eliminate wrinkling defects, significantly lower component spring-back, and improve processing quality. (3) The soft contact near-uniform load application between the elastic die and the initial sheet blank 3 can effectively reduce or avoid scratches on the surface of the component and improve the surface quality. (4) After the initial sheet blank is processed into the curved-surface formed part, if the accuracy does not meet the requirement, local quantitative compensation can be performed on a die profile corresponding to the surface to be compensated by using the elastic compensation pad 10, a high-accuracy curved-surface shell component can be formed without or with minimal die repair. This can greatly reduce die repair time and cost, thereby shortening a manufacturing cycle and lowering the manufacturing cost. (5) In this embodiment, an elastomer (elastic die or elastic compensation pad 10) serves as a forming medium, the elastomer is a solid medium with a pressure bearing capacity much greater than that of a gas and fluid, and can bear a pressure greater than 200 MPa. The elastomers made of different materials can be replaced according to a forming load required by the formed part, which has stronger adaptability and wider application scope. (6) A process allowance of the initial sheet blank 3 is very small, which, compared with conventional stretch forming and deep drawing processes, can significantly improve material utilization and reduce manufacturing cost.

It should be noted that the elastic die in this embodiment may be in various forms, such as a flat plate, a laminated plate, an integral block or a distributed plate. Elastic dies in various shapes can be adopted independently or in combination.

As a preferred implementation, the elastic die is made of polyurethane, nylon, rubber or polytetrafluoroethylene plastic, preferably polyurethane with Shore hardness of 85 HA. If the polyurethane with Shore hardness of 85 HA cannot meet use requirements, the polyurethane with Shore hardness of 90 HA, the polyurethane with Shore hardness of 100 HA or nylon can be selected. The shape of the elastic die is a flat plate shaped or an integral curved-surface block shaped. The thickness of the elastic die ranges from 1 mm to 1000 mm.

This embodiment can be applied to the forming of the curved-surface component made of metal and other materials, such as a stainless steel curved-surface component, an aluminum alloy curved-surface component, a magnesium alloy curved-surface component and a high-temperature alloy curved-surface component. As a preferred implementation, the target curved-surface component 9 has the thickness to ranging from 0.5 mm to 80 mm, and the maximum side length dimension lo ranging from 50 mm to 5000 mm. A curved-surface shape of the target curved-surface component 9 is a hyperboloid, including a hyperboloid in the same direction or a hyperboloid in the opposite direction (a saddle surface).

In this embodiment, the elastic die can spring back to an original shape after the press forming is finished and the die is opened, and the elastic die can be reused until it is broken and scrapped. When a compression rate of the elastic die is less than 60%, the service life of the elastic die can reach at least thousands of times.

Embodiment II

This embodiment provides a curved-surface component forming device 100, as shown in FIG. 3 and FIG. 4. One of the male die device 2 and the female die device 4 is the rigid die, and the other of the male die device 2 and the female die device 4 is the elastic die. The elastic die includes at least one first elastic body 11, and multiple first elastic bodies 11 are arranged in a stacked manner.

As a preferred implementation, each first elastic body 11 of the elastic die is flat-shaped, the initial sheet blank 3 and the curved-surface formed part are both defined as parts to be processed. From one side adjacent to the part to be processed to one side away from the part to be processed, outer contour dimensions of the multiple first elastic bodies 11 sequentially decrease. The elastic die can generate a deformation corresponding to the initial sheet blank 3 or the surface of the curved-surface formed part by pressing against the initial sheet blank 3 or the curved-surface formed part, where the deformation is convex or concave, thereby forming an elastic male die (as shown in FIG. 4) or an elastic die to play the role of a male die or a die. The flat-shaped first elastic body 11 is convenient to process. By combining the multiple flat-shaped first elastic bodies 11 to form an elastic die, the processing process can be simplified and the cost can be reduced.

In this embodiment, the device further includes an upper die plate 1 and a lower die plate 5. The upper die plate 1 is fixedly connected with one of the male die device 2 or the female die device 4, and the lower die plate 5 is fixedly connected with the other of the male die device 2 or the female die device 4. Taking a situation that the male die device 2 is an elastic die and the male die device 2 is connected with the upper die plate 1 as an example, the upper die plate 1 is provided with multiple bolts 7, and the uppermost first elastic body 11 on the elastic die is in contact with a lower surface of the upper die plate 1. The bottommost first elastic body 11 on the elastic die is connected with a screw of the upper die plate 1 through steel wire ropes 8, thereby achieving the suspension connection of all the stacked first elastic bodies 11 with the upper die plate 1. The elastic die is connected with the upper die plate to facilitate die opening and part taking. It should be noted that a connection way of the steel wire ropes 8 and the bottommost first elastic body 11 in the elastic die needs to prevent the steel wire ropes 8 from affecting the processing quality of the upper surface of the initial sheet blank 3 or curved-surface formed part.

Other structures of the curved-surface component forming device in this embodiment and their connection relations are the same as those in Embodiment I.

Embodiment III

This embodiment provides a curved-surface component forming device 100, as shown in FIG. 5 and FIG. 6. In this embodiment, one of the male die device 2 and the female die device 4 is the rigid die, and the other of the male die device 2 and the female die device 4 is the elastic die. The elastic die includes a curved-surface elastomer 12, and a working surface of the curved-surface elastomer 12 is a convex curved surface or a concave curved surface. In this embodiment, the elastic die is a curved-surface elastomer 12 in the form of an integral curved-surface block, and the elastic die can function as the male die device 2 or the female die device 4.

In this embodiment, the device further includes an upper die plate 1 and a lower die plate 5. The upper die plate 1 is fixedly connected with one of the male die device 2 or the female die device 4, and the lower die plate 5 is fixedly connected with the other of the male die device 2 or the female die device 4. Taking a situation that the male die device 2 is the elastic die and the male die device 2 is connected with the upper die plate 1 as an example, a surface, adjacent to the lower die plate 5, of the curved-surface elastomer 12 is a convex curved surface, and a surface, adjacent to the curved-surface elastomer 12, of the female die device 4 is a concave curved surface. The curved-surface elastomer 12 in the form of an integral curved-surface block is directly fixed to the upper die plate 1, and the curved-surface elastomer 12 in the form of an integral curved-surface block is configured to directly press-form the initial sheet blank 3. The initial sheet blank 3 is in a soft contact state with the elastic die, and the elastic die and the initial sheet blank 3 are deformed simultaneously to gradually press the initial sheet blank 3 against a cavity of the lower die plate 5.

Other structures of the curved-surface component forming device 100 in this embodiment and their connection relations are the same as those in Embodiment I.

Embodiment IV

This embodiment provides a curved-surface component forming device 100, as shown in FIG. 7 and FIG. 8. One of the male die device 2 and the female die device 4 is the rigid die, and the other of the male die device 2 and the female die device 4 is the elastic die. The elastic die includes a rigid male die 6 and a second elastic body 13. The second elastic body 13 is arranged between the rigid male die 6 and the part to be processed, and the second elastic body 13 can be deformed to a convex shape by pressing against the part to be processed. The second elastic body 13 directly acts on the part to be processed to play a role of a male die, the effect of the elastic die can be achieved after the second elastic body 13 and the rigid male die 6 are combined, that is, the integral body formed by the combination of the second elastic body 13 and the rigid male die 6 serves as the elastic die.

It should be noted that the female die device 4 can also be the elastic die, that is, the elastic die includes the rigid female die 4 and the second elastic body 13, and the second elastic body 13 is arranged between the rigid female die 4 and the part to be processed.

In this embodiment, the device further includes an upper die plate 1 and a lower die plate 5. The upper die plate 1 is fixedly connected with one of the male die device 2 or the female die device 4, and the lower die plate 5 is fixedly connected with the other of the male die device 2 or the female die device 4. Taking a situation that the male die device 2 is the elastic die and the male die device 2 is connected with the upper die plate 1 as an example, the upper die plate 1 is fixedly connected with the rigid male die 6, and the lower die plate 5 is fixedly connected with the rigid female die device 4. A profile of the rigid male die 6 is in fit with that of the rigid female die device 4, and the difference in curvature radius between the profile of the rigid male die 6 and the profile of the rigid female die device 4 is greater than the thickness of the initial sheet blank 3.

The second elastic body 13 is flat-shaped. The flat-shaped second elastic body 13 can be freely placed on the initial sheet blank 3, or the flat-shaped second elastic body 13 can be fixedly connected with the profile of the rigid male die 6 in a wrapping manner, and then the initial sheet blank 3 can be press-formed. The lower die plate 5 is arranged on a workbench of a press, which is a hydraulic press, a servo press and the like. The upper die plate 1 is configured to connect with a press beam, which can drive the upper die plate 1 to move up and down, and the upper die plate 1 can drive the connected rigid male die 6 to move up and down.

Other structures of the curved-surface component forming device 100 in this embodiment and their connection relations are the same as those in Embodiment I.

Embodiment V

As shown in FIG. 1 to FIG. 12, this embodiment provides a curved-surface component forming method based on the curved-surface component forming device 100 in Embodiment I, including the following steps.

In S1, an initial sheet blank 3 is formed into a curved-surface formed part by adopting a first method or a second method.

The first method is as follows. A male die device 2 and a female die device 4 are both configured as rigid dies. At least one elastic compensation pad 10 is arranged between the male die device 2 and the initial sheet blank 3 and/or between the female die device 4 and the initial sheet blank 3. By moving the male die device 2 toward the female die device 4 and/or moving the female die device 4 toward the male die device 2, the elastic compensation sheet blank 10 and the initial sheet blank 3 are pressed against each other, and the initial sheet blank 3 is formed into a curved-surface formed part.

The second method is as follows. One of the male die device 2 and the female die device 4 is configured as the rigid female die and the other of the male die device 2 and the female die device 4 is configured as an elastic die. By moving the male die device 2 toward the female die device 4 and/or moving the female die device 4 toward the male die device 2, the initial sheet blank 3 is formed into a curved-surface formed part.

In S2, a position of a surface to be compensated on the curved-surface formed part is obtained, the elastic compensation pad 10 is arranged at each surface to be compensated of the curved-surface component, and the curved-surface formed part is pressed again by adopting the male die device 2 and the female die device 4 in the first method or second method until a deviation between contour dimensions of the curved-surface formed part and a target curved-surface component 9 is less than or equal to a specified value. The curved-surface component forming device 100 undergoes multiple cycles of unloading, die opening, adjustment of the elastic compensation pad 10, and re-pressing/reshaping to ensure the curved-surface formed part conforms perfectly to the lower die plate 5.

In this embodiment, S1 further includes: before the initial sheet blank 3 is pressed, the shape and the dimension of the initial sheet blank 3 are obtained based on the shape and the dimension of the target curved-surface component 9.

In this embodiment, the elastic die includes at least one first elastic body 11, and multiple first elastic bodies 11 are arranged in a stacked manner in a direction from the upper die plate 1 to the lower die plate 5.

S1 further includes: before the initial sheet blank 3 is pressed, the material, the shape and the dimension of the elastic die are obtained based on the shape and the dimension of the target curved-surface component 9 and the shape and the dimension of the initial sheet blank 3; the thickness of each first elastic body 11 is determined, the number of the first elastic bodies 11 according to a thickness of the elastic die and the thickness of each first elastic body are obtained, and a stacking manner of the multiple first elastic bodies is obtained.

It should be noted that when the male die device and the female die device are both rigid dies, before the initial sheet blank 3 is pressed, the material, the shape and the dimension of the elastic compensation pad can be obtained based on the shape and the dimension of the target curved-surface component 9 and the shape and the dimension of the initial sheet blank 3.

In this embodiment, S1 includes a method for obtaining the shape and the dimension of the initial sheet blank, including the steps as follows. The shape and the dimension of the initial sheet blank 3 are obtained based on the shape of a developed blank corresponding to a developed target curved-surface component 9; an outer contour dimension of the initial sheet blank 3 is increased by an allowance of 20 mm to 80 mm based on the dimension of the developed blank for the target curved-surface component 9, and the thickness of the initial sheet blank 3 is equal to that of the target curved-surface component 9, or the thickness of the initial sheet blank 3 is increased by an allowance of 0.1 mm to 8 mm based on the thickness of the target curved-surface component 9. As a preferred implementation, the target curved-surface component 9 is developed by using UG, CATIA and other three-dimensional software to obtain the shape and dimensional data of the developed blank. After the dimension of the initial sheet blank 3 is obtained, the initial sheet blank 3 is obtained by cutting through one of plasma cutting, laser cutting or linear cutting methods, and then an edge of the initial sheet blank 3 is chamfered and polished by grinding until a removal depth reaches 5%-15% of the wall thickness.

In this embodiment, S1 includes a method for obtaining the dimension of the elastic die, including the steps as follows. The thickness of the elastic die is 1 to 2 times a maximum height of the target curved-surface component 9; the thickness of each first elastic body 11 is obtained, and the number of the first elastic bodies 11 is obtained based on the thickness of the elastic die and the thickness of each first elastic body 11. The contour dimension of the elastic die is not less than that of the initial sheet blank 3. If the elastic die and the initial sheet blank 3 are rectangular, a length and width of the elastic die are not less than those of the initial sheet blank 3. The thickness of each first elastic body 11 may be determined according to the dimension (depth) of the formed part in a die-closing direction. In general, all the first elastic bodies have a same thickness, and the thickness of each first elastic body 11 ranges from 2 mm to 50 mm.

In this embodiment, S1 includes a method for obtaining the position of the surface to be compensated on the curved surface forming part, including the steps as follows. 3D scanning is performed on the curved-surface formed part after spring-back, a forming surface of the male die device 2, and a forming surface of the female die device 4 to obtain contour dimensional data of the curved-surface formed part both before and after spring-back. The spring-back law or data of the curved-surface formed part is obtained according to the contour dimensional data of the curved-surface formed part before and after spring-back, and the position of the surface to be compensated of the curved-surface formed part is obtained based on the spring-back law or data of the curved-surface formed part, and then the quantity, the position, the shape and the dimension of the elastic compensation pad are determined. The elastic compensation pad 10 is placed according to a designed position to press-form the curved-surface formed part again.

As a preferred implementation, when one of the male die device 2 and the female die device 4 is the elastic die, it is possible to scan only the curved-surface molded part after spring-back and the profile of the rigid die in the male die device 2 and the female die device 4, and then the elastic compensation pad 10 is arranged on the profile of the rigid die of the male die device 2 and the female die device 4.

It should be noted that the method for obtaining the position of the compensation surface is not limited to the foregoing ways, and the position of the compensation surface may also be obtained by other ways. For example, three-dimensional scanning is performed on the curved-surface formed part after spring-back to obtain the contour dimensional data of the curved-surfaced formed part, the contour dimensional data of the curved-surface formed part is compared with that of the target curved-surface component, and a portion of the curved-surface formed part where a deviation of a contour dimension from the target curved-surface component 9 exceeds a specified value is a surface to be compensated of the curved-surface formed part.

In this embodiment, the method further includes S3: after the curved-surface formed part meets design requirements (such as dimensional accuracy requirements), the allowance is cut off by methods such as plasma cutting, laser cutting or linear cutting to obtain the final target curved-surface component 9.

As a first feasible implementation, the curved-surface component forming method provided by this embodiment includes the following steps.

• • In Step S1, the shape and the dimension of the initial sheet blank 3 are determined by reversing based on the shape and the dimension of the target curved-surface component 9.
  • In Step S2, one of the male die device 2 and the female die device 4 is a rigid die, and the other of the male die device 2 and the female die device 4 is an elastic die. The material, the shape, the dimension and the stacking configuration of the required elastic die during press-forming are determined.
  • In Step S3, the initial sheet blank 3 is placed on the rigid female die device 4 below, and the elastic die above serves as the male die device 2.
  • In Step S4, the elastic die moves downward, the elastic die is driven to interact with the initial sheet blank 3, and near-uniformly distributed normal load is applied to the initial sheet blank 3. The initial sheet blank 3 is pressed to gradually conform to the cavity of the female die device 4 and is formed into a curved-surface formed part.
  • In Step S5, unloading and die opening are performed, the elastic die springs back to its initial shape, and the curved-surface formed part springs back. A 3D scanner is configured to scan the appearance of the curved-surface formed part after spring-back to obtain the spring-back law of the curved-surface formed part.
  • In Step S6, if the contour dimension of the curved-surface formed part does not meet the accuracy requirement, the curved-surfaced formed part is placed on the female die device 4 again, and then the elastic compensation pads 10 are placed at local positions of an upper side and a lower side of the curved-surface formed part, and the die is closed again to press and reshape the curved-surface formed part.
  • In Step S7, unloading and die opening are performed to take out the curved-surface formed part, when the curved-surface formed part meets the accuracy requirement, the allowance is cut off to obtain the final curved-surface component.
  • In Step 3, the elastic die includes a rigid male die 6 and a second elastic body 13, the upper die plate 1 is fixedly connected with the rigid male die 6, and the lower die plate is fixedly connected with the rigid female die device 4. The flat-shaped second elastic body 13 is freely placed on the initial sheet blank 3, or the flat-shaped second elastic body 13 can be fixedly connected with the profile of the rigid male die 6 in a wrapping manner, and the initial sheet blank 3 is subjected to press-forming. The lower die plate 5 is arranged on a workbench of a press. The press is a hydraulic press, a servo press and the like. The upper die plate 1 is configured to connect with the press beam, which can drive the upper die plate 1 to move up and down, and the upper die plate 1 can drive the connected rigid male die 6 to move up and down.

As a second feasible implementation, the steps of the curved-surface component forming method provided in this embodiment are the same as those in the first feasible implementation mode, and the differences are as follows.

In Step 3, the initial sheet blank 3 is placed on the female die device 4. Multiple flat-shaped first elastic bodies 11 made of 85 HA polyurethane are stacked into a certain geometric configuration and placed on the initial sheet blank 3, and then are in suspension connection with the upper template 1 through the steel wire rope 8 and the bolt 7. The initial sheet blank 3 is subjected to press-forming by using the multiple first elastic bodies 11 arranged in a stacked manner. The female die device 4 and the lower die plate 5 are fixed together, and then fixed to the workbench of the press. The press is a hydraulic press and a servo press. The upper die plate 1 is connected with the press beam, and the press beam drives the upper die plate 1 to move up and down, thereby implementing die closing and die opening.

As a third feasible implementation, the steps of the curved-surface component forming method provided in this embodiment are the same as those in the first feasible implementation mode, and the differences are as follows.

In Step 3, the initial sheet blank 3 is placed on the female die device 4, the elastic die in the form of an integral curved-surface block is directly fixed to the upper die plate 1, and the elastic die in the form of an integral curved-surface block is configured to directly press-form the initial sheet blank 3. The female die device 4 and the lower die plate 5 are fixed together, and then fixed to a workbench of the press. The press is a hydraulic press and a servo press. The upper die plate 1 is connected with the press beam, and the press beam drives the upper die plate 1 to move up and down, thereby implementing die closing and die opening.

As a fourth feasible implementation, the curved-surface component forming method provided by this embodiment includes the following steps.

• • In Step S1, the shape and dimension of the initial sheet blank 3 are determined by reversing based on the shape and the dimension of the target curved-surface component 9.
  • In Step S2, the male die device 2 and the female die device 4 are both configured as rigid dies, the material, the shape, the dimension and the placing position of the required elastic compensation pad 10 are determined when the initial sheet blank 3 is press-formed.
  • In Step S3, the initial sheet blank 3 is placed between the male die device 2 and the female die device 4, the elastic compensation pad 10 is placed between the male die device 2 and the initial sheet blank 3 and/or between the female die device 4 and the initial sheet blank 3.
  • In Step S4, the elastic die moves downward, and the elastic die is driven to interact with the initial sheet blank 3, a near-uniformly distributed normal load is applied to the initial sheet blank 3. The initial sheet blank 3 is pressed to gradually conform to the cavity of the female die device 4 and is formed into a curved-surface formed part.
  • In Step S5, unloading and die opening are performed, the elastic die is enable to spring back to an original shape, the curved-surface formed part springs back, and a 3D scanner is configured to scan the appearance of the curved-surface formed part after spring-back to obtain the spring-back law of the curved-surface formed part.
  • In Step S6, if the contour dimension of the curved-surface formed part does not meet the accuracy requirement, the curved-surfaced formed part is placed on the female die device 4 again, and then the elastic compensation pads 10 with required material, shape and size are placed at local positions (surfaces to be compensated) of an upper side and a lower side of the curved-surface formed part, and the die is closed again to press and reshape the curved-surface formed part.
  • In Step S7, unloading and die opening are performed to take out the curved-surface formed part, and when the curved-surface formed part meets the accuracy requirement, the allowance is cut off to obtain the final curved-surface component.

It should be noted that the upper die plate 1 and the lower die plate 5 in the present disclosure only indicate upper and lower positions relative to a press space, and the positions of the upper die plate 1 and lower die plate 5 can be interchanged. The upper die plate 1 is usually connected with the male die device 2, and the lower die plate 5 is usually connected with the female die device 4. The female die device 4 is generally in the form of an integral block and is the rigid die, and its profile is mainly configured to ensure the contour accuracy of the target curved-surface component 9. There is no specific requirements on the profile of the male die device 2, which does not to completely match the female die device 4. However, it may be that the female die device 4 is the elastic die and the male die device 2 is the rigid mold. In this case, the placement order of the first elastic body 11, the second elastic body 13 and the initial sheet blank 3 can be changed. That is, besides being placed above the initial sheet blank 3, the first elastic body 11 and the second elastic body 13 may also be placed below the initial sheet blank 3, and the placement order is determined according to the shape and dimension characteristics of the formed part and the forming effect.

Several examples are used for illustration of the principles and implementations of the present disclosure. The description of the embodiments is merely used to help illustrate the method and its core principles of the present disclosure. In addition, a person of ordinary skill in the art can make various variations in terms of specific implementations and scope of application in accordance with the thoughts of the present disclosure. In conclusion, the content of this specification shall not be construed as a limitation to the present disclosure.