A device for high-rate fluid-driven precise forming of sheet metal and a forming method thereof

Abstract

The application discloses a kind of high-speed fluid driving sheet accurate forming device and its forming method, including electromagnetic forming coil, coil reinforcement plate, conductive driving block, driving punch, fluid constraint mould and forming mould, electromagnetic forming coil is installed in coil reinforcement plate, the lower end of driving punch is provided with coil reinforcement plate, and the upper end is sealed slidingly connected with the constraint cavity in fluid constraint mould, forming mould is set to be able to press the sheet in the upper of constraint cavity, fluid with liquid level lower than sheet is arranged in constraint cavity, and the side of forming mould close to sheet is provided with forming cavity.The application adopts inverted forming device, when liquid level is lower than sheet surface, electromagnetic forming coil discharge can drive punch to accelerate liquid.When high-speed liquid and sheet contact, sheet is endowed with very high deformation speed, so as to improve the forming limit of material.

Description

Technical Field

[0001] The present invention relates to the technical field of material processing and forming, and in particular to a device for accurately forming sheet materials driven by a high-speed fluid and a forming method thereof. Background Art

[0002] Electromagnetic forming (EMF) is a high-speed machining technique that utilizes electromagnetic forces exerted on metals in a strong pulsed magnetic field to cause them to plastically deform. This process significantly increases the material's ductility and forming limit. However, a major challenge with EMF is the difficulty in controlling part shape under high-velocity impacts. Consequently, many researchers have combined EMF with traditional forming processes.

[0003] The patented "Method for Collaboratively Controlling Springback and Fracture of Complex Curved Parts by Stamping and Magnetic Pulse Forming" combines conventional stamping with electromagnetic forming. Using conventional stamping, sheet metal is initially bent into a complex curved part. Then, a coil within a punch discharges the sheet metal for secondary forming, resulting in a more precisely shaped, complex curved part. However, manufacturing the coil and properly inserting it into the mold while ensuring a long lifespan for both coil and mold present significant challenges.

[0004] The patent, "An Electromagnetic Forming Device and Method for Forming Sheet Metal by Fluid Impact," utilizes electromagnetic force to drive the fluid into high-speed motion, achieving part formation. The coil and mold manufacturing are relatively simple. However, this method also presents challenges, such as difficulty achieving high fluid velocity in the initial forming phase and the electromagnetic force decreasing as the distance between the coil and the drive plate increases, thus affecting forming quality. Summary of the Invention

[0005] The object of the present invention is to provide a device and a forming method for accurately forming sheet metal driven by high-speed fluid, thereby solving the above-mentioned problems.

[0006] To achieve the above-mentioned objectives, the present invention first discloses a device for precise forming of sheet metal driven by high-speed fluid, comprising an electromagnetic forming coil, a coil reinforcement plate, a conductive driving block, a driving punch, a fluid constraint mold and a forming mold, wherein the electromagnetic forming coil is installed in the coil reinforcement plate, the lower end of the driving punch is provided with the coil reinforcement plate, and the upper end is sealed and slidably connected with the constraint cavity in the fluid constraint mold, the forming mold is configured to press the sheet metal above the constraint cavity, the constraint cavity is provided with a fluid with a liquid level lower than that of the sheet metal, and the forming mold is provided with a forming cavity on the side close to the sheet metal.

[0007] Furthermore, a fixed base plate is provided below the coil reinforcement plate, and a telescopic driving member that can drive the coil reinforcement plate to move upward is provided on the base plate, and the telescopic end of the telescopic driving member is connected to the coil reinforcement plate.

[0008] Furthermore, the telescopic driving member is a spring or a cylinder.

[0009] Furthermore, a conductive recoil plate is fixedly mounted on the bottom of the coil reinforcement plate, the coil reinforcement plate is abutted against the upper end surface of the conductive recoil plate, and the coil reinforcement plate with the electromagnetic forming coil inside is fixedly mounted on the bottom of the conductive recoil plate.

[0010] Furthermore, the fluid constraint mold or forming mold is provided with a countersink capable of accommodating the sheet material, the countersink is clearance-matched with the sheet material, and a lateral flow channel connecting the edge of the sheet material and the constraint cavity is formed in the countersink.

[0011] Furthermore, it also includes a lateral electromagnetic forming coil, a lateral coil reinforcement plate, a lateral conductive driving block, a lateral fluid constraint mold and a lateral driving punch. The fluid constraint mold, the forming mold and the outer side of the sheet form a fluid flow channel at the end of the sheet. The lateral electromagnetic forming coil is installed in the lateral coil reinforcement plate, the lateral conductive driving block is arranged above the lateral coil reinforcement plate, the lateral coil reinforcement plate is installed at the lower end of the lateral driving punch, the upper end of the lateral driving punch is slidably connected to the lateral constraint cavity of the lateral fluid constraint mold, the lateral constraint cavity is filled with fluid, and the upper end of the lateral constraint cavity is sealed and connected to the fluid flow channel at the end of the sheet.

[0012] Furthermore, the driving punch includes a plurality of split driving punches, and the split driving punches are sealed and slidably connected with each other.

[0013] The present invention then discloses a method for precise sheet metal forming driven by high-speed fluid, comprising any of the above-mentioned devices for precise sheet metal forming driven by high-speed fluid, and comprising the following steps:

[0014] S1. Installing the fluid confinement die, the electromagnetic forming coil, the coil reinforcement plate, the conductive driving block, and the driving punch, wherein the driving punch and the fluid confinement die form the confinement cavity;

[0015] S2, adding fluid into the constraint cavity, controlling the liquid level at the upper end of the fluid to be lower than the upper end surface of the fluid constraint mold;

[0016] S3, placing a sheet material on the upper end surface of the fluid confinement mold, and controlling the forming mold to press the edge of the sheet material onto the upper end surface of the fluid confinement mold;

[0017] S4. Power the electromagnetic forming coil to enable the driving punch to drive the fluid to impact the sheet material.

[0018] Furthermore, in step S1, the sheet material is pre-deformed from one side to increase the surface area of ​​the sheet material, and then the sheet material is subjected to fluid impact from the other side of the pre-deformation.

[0019] Furthermore, in step S4, the lateral electromagnetic forming coil is controlled to discharge simultaneously so that the lateral driving punch drives the fluid to impact the edge of the sheet material.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] (1) The present invention adopts an inverted forming device. When the liquid level is lower than the sheet surface, the discharge of the electromagnetic forming coil can drive the punch to accelerate the liquid. When the high-speed liquid contacts the sheet, the sheet is given a very high deformation speed, thereby improving the forming limit of the material;

[0022] (2) The present invention sets a spring or cylinder at the bottom of the electromagnetic forming coil. At the initial moment, the spring and cylinder are compressed due to the pressure of the liquid and the punch, as well as the preload applied to the spring. When the electromagnetic forming coil is discharged, the punch drives the liquid upward, and the compressed energy of the spring and cylinder is released to drive the electromagnetic forming coil upward. This reduces the distance between the electromagnetic forming coil and the high-conductivity drive plate, thereby improving the forming efficiency.

[0023] (3) The present invention sets a high-conductivity driving plate at the bottom of the electromagnetic forming coil. When the electromagnetic forming coil discharges, the upper and lower parts of the electromagnetic forming coil will be subjected to downward and upward electromagnetic forces due to the concentrated magnetic field. As the upper high-conductivity driving plate and the punch move upward, the pressure of the upper driving plate on the electromagnetic forming coil decreases, so that the electromagnetic forming coil also moves upward, thereby reducing the distance between the electromagnetic forming coil and the high-conductivity driving plate, thereby improving the forming efficiency;

[0024] (4) The present invention provides a radial side-pushing hydraulic pressure at the end of the sheet material, thereby significantly increasing the forming height of the part;

[0025] (5) The present invention sets the punch and the electromagnetic forming coil as a separate structure, which can form the sheet metal in different areas, further improving the flexibility of forming;

[0026] (6) The present invention first pre-deforms the sheet material to increase the surface area of ​​the sheet material, and then performs reverse fluid impact, thereby reducing phenomena such as cracking that may occur when the parts are deformed.

[0027] The present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0029] Figure 1 This is a schematic diagram of a forming device disclosed in Example 1 in which the fluid surface is flush with the bottom surface of the sheet material;

[0030] Figure 2 This is a schematic diagram of the forming device disclosed in the first embodiment in which the fluid surface is lower than the bottom surface of the sheet material;

[0031] Figure 3 This is a schematic diagram of a compressed spring installed at the bottom of the electromagnetic forming coil disclosed in Example 2;

[0032] Figure 4 This is a schematic diagram of the second embodiment in which, after discharge, the driving plate drives the punch to squeeze the fluid, and the compressed spring pushes the electromagnetic forming coil to move closer to the driving plate;

[0033] Figure 5 This is a schematic diagram of the electromagnetic forming coil driven by the cylinder to move according to the second embodiment;

[0034] Figure 6 This is a schematic diagram of driving the coil to move by arranging a high-conductivity driving plate at the bottom of the electromagnetic forming coil disclosed in the third embodiment;

[0035] Figure 7 This is an initial structural diagram of the fluid confinement chamber with lateral channels disclosed in Example 4;

[0036] Figure 8 This is a diagram of a deformed structure of the fluid confinement chamber with a lateral channel disclosed in Example 4;

[0037] Figure 9 This is the initial structural diagram of the fifth embodiment in which an independent lateral fluid drive is provided at the end of the sheet;

[0038] Figure 10 This is a diagram of a deformed structure in which an independent lateral fluid drive is provided at the end of the sheet material according to the fifth embodiment;

[0039] Figure 11 This is an initial structural diagram of the split driving punch and split electromagnetic forming coil disclosed in Example 6;

[0040] Figure 12 This is a schematic diagram of the left electromagnetic forming coil discharging first to drive the left punch to move first and the sheet metal to deform according to the sixth embodiment;

[0041] Figure 13 Schematic diagram of the side punch moving and sheet metal deformation driven by the discharge of the right electromagnetic forming coil disclosed in Example 6;

[0042] Figure 14 This is a schematic diagram of the structure of first deforming the horizontal plate disclosed in the seventh embodiment;

[0043] Figure 15 This is a schematic diagram of placing the deformed sheet material in the reverse direction on the forming device according to the seventh embodiment;

[0044] Figure 16 This is a schematic diagram of the final forming of the sheet material disclosed in Example 7.

[0045] Legend:

[0046] 1. Forming die; 2. Fluid constraint die; 3. Sheet material; 4. Fluid; 5. Driving punch; 6. Electromagnetic forming coil; 7. Coil reinforcement plate; 8. Conductive driving block; 9. Bottom plate; 10. Spring; 11. Cylinder; 12. Conductive recoil plate; 13. Lateral flow channel; 14. Lateral electromagnetic forming coil; 15. Fluid flow channel at the end of sheet material; 16. Split driving punch; 17. Lateral coil reinforcement plate; 18. Lateral conductive driving block; 19. Lateral fluid constraint die; 20. Lateral driving punch; 21. Constraint cavity; 22. Lateral constraint cavity. DETAILED DESCRIPTION

[0047] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered by the claims.

[0048] Example 1:

[0049] like Figure 1 and 2As shown, the present invention first discloses a device for high-speed fluid-driven precision forming of sheet metal. The device comprises an electromagnetic forming coil 6, a coil reinforcement plate 7, a conductive drive block 8, a drive punch 5, a fluid confinement die 2, and a forming die 1. The electromagnetic forming coil 6 is mounted within a groove in the coil reinforcement plate 7. In this embodiment, the coils are all forming coils that provide electromagnetic force, thereby increasing the strength and rigidity of the electromagnetic forming coil 6 and preventing deformation due to reaction force during discharge. The conductive drive block 8 is a high-conductivity drive block, thereby increasing the forming speed. The coil reinforcement plate 7 is provided at the lower end of the drive punch 5, and the upper end is in sealing and sliding contact with the confinement chamber 21 within the fluid confinement die 2. The forming die 1 is configured to press the sheet metal 3 against the upper portion of the confinement chamber 21. The confinement chamber 21 contains a fluid 4 whose liquid level is lower than that of the sheet metal 3. In this embodiment, the fluid 4 is liquid water. A forming cavity is provided on the side of the forming die 1 near the sheet metal 3. The forming cavity matches the shape of the sheet metal 3 to be formed. Therefore, when the liquid level is below the surface of the sheet metal 3, the discharge of the electromagnetic forming coil 6 drives the drive punch 5 to accelerate the fluid 4. When the high-speed fluid 4 contacts the sheet material 3, the sheet material 3 is given a very high deformation speed, thereby increasing the forming limit of the material.

[0050] The present invention then discloses a method for precise sheet metal forming driven by high-speed fluid, comprising the above-mentioned device for precise sheet metal forming driven by high-speed fluid, and comprising the following steps:

[0051] S1. Install the fluid confinement die 2, the electromagnetic forming coil 6, the coil reinforcement plate 7, the conductive driving block 8, and the driving punch 5. The driving punch 5 and the fluid confinement die 2 form a confinement cavity 21.

[0052] S2. Add fluid 4 into the constraint chamber 21 and control the liquid level of the upper end of the fluid 4 to be lower than the upper end surface of the fluid constraint mold 2, thereby providing space for the fluid 4 to accelerate;

[0053] S3. Place the sheet material 3 on the upper end surface of the fluid confinement mold 2, with the middle portion of the sheet material 3 covering the upper end opening of the confinement cavity 21. Control the forming mold 1 to seal and press the edge of the sheet material 3 against the upper end surface of the fluid confinement mold 2.

[0054] S4. Power is supplied to the electromagnetic forming coil 6 to enable the driving punch 5 to drive the fluid 4 to accelerate rapidly until the sheet material 3 is impacted and formed.

[0055] Example 2:

[0056] like Figure 3-5As shown, in this embodiment, a fixed base plate 9 is provided below the coil reinforcement plate 7, and a telescopic drive member that can drive the coil reinforcement plate 7 to move upward is provided on the base plate 9, and the telescopic end of the telescopic drive member is connected to the coil reinforcement plate 7. Specifically, the telescopic drive member is a spring 10 or a cylinder 11. Therefore, at the initial moment, due to the pressure of the fluid 4 and the driving punch 5, as well as the application of preload force to the spring 10, the spring 10 and the cylinder 11 are compressed. When the electromagnetic forming coil 6 is discharged, the driving punch 5 drives the fluid 4 to move upward, and the compressed energy of the spring 10 and the cylinder 11 is released to drive the coil reinforcement plate 7 to move upward. This reduces the distance between the coil reinforcement plate 7 and the conductive drive block 8, ensures a larger electromagnetic force between the coil reinforcement plate 7 and the conductive drive block 8, and improves the forming efficiency.

[0057] Example 3:

[0058] like Figure 6 As shown, in this embodiment, a conductive recoil plate 12 is fixedly mounted on the bottom of the coil reinforcement plate 7. The coil reinforcement plate 7 abuts the upper end surface of the conductive recoil plate 12. A coil reinforcement plate 7, which houses an electromagnetic forming coil 6, is fixedly mounted on the bottom of the conductive recoil plate 12. When the electromagnetic forming coil 6 discharges, both the upper and lower portions of the coil reinforcement plate 7 are subjected to downward and upward electromagnetic forces due to the concentrated magnetic field. As the upper conductive drive block 8 and the drive punch 5 move upward, the pressure exerted by the upper drive punch 5 on the coil decreases, causing the coil to move upward, thereby reducing the distance between the coil and the conductive drive block 8 and improving forming efficiency. Furthermore, an electromagnetic forming coil 6 is positioned below the conductive recoil plate 12, creating a multi-stage propulsion similar to a rocket launch. Discharging the electromagnetic forming coil 6 below the conductive recoil plate 12 creates a primary propulsion, while discharging the electromagnetic forming coil 6 above the conductive recoil plate 12 creates a secondary propulsion. Furthermore, multiple electromagnetic forming coils 6 can be stacked to create a third or even fourth stage propulsion, enabling rapid acceleration of the drive punch 5 in a very short time.

[0059] Example 4:

[0060] like Figure 7 and 8 As shown, in this embodiment, the fluid-constraining die 2 or forming die 1 is provided with a counterbore for accommodating the sheet material 3. The counterbore is loosely fitted with the sheet material 3, and a lateral flow channel 13 is formed in the counterbore, connecting the edge of the sheet material 3 and the constraint cavity 21. This creates a radial hydraulic pressure at the end of the sheet material 3, significantly increasing the formed height of the part.

[0061] Embodiment 5:

[0062] like Figure 9 and 10As shown, in this embodiment, it also includes a lateral electromagnetic forming coil 14, a lateral coil reinforcement plate 17, a lateral conductive drive block 18, a lateral fluid constraint die 19, and a lateral drive punch 20. The fluid constraint die 2, the forming die 1, and the outer side of the sheet 3 form a sheet end fluid flow channel 15. The sheet end fluid flow channel 15 is a sealed annular flow channel arranged at the outer edge of the sheet 3. The lateral electromagnetic forming coil 14 is installed in the lateral coil reinforcement plate 17. The lateral conductive drive block 18 is arranged above the lateral coil reinforcement plate 17. The lateral coil reinforcement plate 17 is installed at the lower end of the lateral drive punch 20. The upper end of the lateral drive punch 20 is in sliding contact with the lateral constraint cavity 22 of the lateral fluid constraint die 19. The lateral constraint cavity 22 is filled with fluid 4. The upper end of the lateral constraint cavity 22 is sealed with the sheet end fluid flow channel 15. Similarly, a radial side push hydraulic pressure is provided at the end of the sheet 3, thereby significantly increasing the forming height of the part.

[0063] During the control process, the main steps are the same as those in the first embodiment, except that, in step S4 , the lateral electromagnetic forming coil 14 is simultaneously controlled to discharge so that the lateral driving punch 20 drives the fluid to impact the edge of the sheet material 3 .

[0064] Example 6:

[0065] like Figure 11-13 As shown, the driving punch 5 includes a plurality of split driving punches 16, which are sealed and slidably connected with each other. Correspondingly, the electromagnetic forming coil 6 is also set as a one-to-one corresponding split structure, so that the sheet material 3 can be formed in partitions, further improving the forming flexibility, thereby meeting the needs of sheet material forming that requires a sequential fluid driving process.

[0066] Embodiment seven:

[0067] In this embodiment, the main structure is basically the same as that of the fourth embodiment, except that: Figure 14-16 As shown, in step S1, the sheet material 3 is pre-deformed from one side to increase the surface area of ​​the sheet material 3, and then the sheet material 3 is subjected to fluid impact from the other side of the pre-deformation, thereby reducing the phenomenon of cracking and the like that may occur when the part is deformed.

[0068] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A device for precise forming of sheet metal driven by high-speed fluid, characterized in that: The invention comprises an electromagnetic forming coil (6), a coil reinforcement plate (7), a conductive driving block (8), a driving punch (5), a fluid constraint die (2) and a forming die (1), wherein the electromagnetic forming coil (6) is installed in a groove of the coil reinforcement plate (7), the lower end of the driving punch (5) is provided with the coil reinforcement plate (7), and the upper end is sealed and slidably connected with the constraint cavity (21) in the fluid constraint die (2), and the forming die (1) is configured to press the sheet material (3) onto the upper portion of the constraint cavity (21). The constraint cavity (21) is provided with a fluid (4) whose liquid level is lower than that of the sheet material (3); the forming mold (1) is provided with a forming cavity on the side close to the sheet material (3); the bottom of the coil reinforcement plate (7) is provided with a conductive recoil plate (12); the coil reinforcement plate (7) is abutted against the upper end surface of the conductive recoil plate (12); the bottom of the conductive recoil plate (12) is fixedly provided with the coil reinforcement plate (7) in which the electromagnetic forming coil (6) is provided; and the lateral electromagnetic forming coil (1 4), a lateral coil reinforcement plate (17), a lateral conductive drive block (18), a lateral fluid constraint die (19) and a lateral drive punch (20), wherein the fluid constraint die (2), the forming die (1) and the outer side of the sheet material (3) form a sheet material end fluid flow channel (15), the lateral electromagnetic forming coil (14) is installed in the lateral coil reinforcement plate (17), the lateral conductive drive block (18) is arranged above the lateral coil reinforcement plate (17), and the lateral coil reinforcement plate (17) is installed At the lower end of the lateral driving punch (20), the upper end of the lateral driving punch (20) is in sliding connection with the lateral constraint cavity (22) of the lateral fluid constraint die (19), the lateral constraint cavity (22) is filled with fluid (4), and the upper end of the lateral constraint cavity (22) is sealed and connected to the fluid flow channel (15) at the end of the sheet material; the driving punch (5) includes a plurality of split driving punches (16) for partitioning the sheet material (3), and the split driving punches (16) are sealed and slidingly connected with each other.

2. The device for precise sheet metal forming driven by high-speed fluid according to claim 1, characterized in that: The fluid constraint mold (2) or the forming mold (1) is provided with a countersink capable of accommodating the plate material (3), the countersink is clearance-matched with the plate material (3), and a lateral flow channel (13) is formed in the countersink to connect the edge of the plate material (3) and the constraint cavity (21).

3. A method for precise sheet metal forming driven by high-speed fluid, comprising the device for precise sheet metal forming driven by high-speed fluid according to any one of claims 1-2, characterized in that: The invention comprises the following steps: S1, installing the fluid constraint mold (2), the electromagnetic forming coil (6), the coil reinforcement plate (7), the conductive driving block (8) and the driving punch (5), wherein the driving punch (5) and the fluid constraint mold (2) form the constraint cavity (21); S2, adding fluid (4) into the constraint cavity (21), and controlling the liquid level of the upper end of the fluid (4) to be lower than the upper end surface of the fluid constraint mold (2); S3, placing a sheet material (3) on the upper end surface of the fluid constraint mold (2), and controlling the forming mold (1) to press the edge of the sheet material (3) onto the upper end surface of the fluid constraint mold (2); S4, energizing the electromagnetic forming coil (6) so that the driving punch (5) drives the fluid (4) to impact the sheet material (3).

4. The high-speed fluid-driven sheet metal precision forming method according to claim 3, characterized in that: In step S1, the sheet material (3) is pre-deformed from one side to increase the surface area of ​​the sheet material (3), and then the sheet material (3) is impacted by a fluid (4) from the other side of the pre-deformation.

5. The high-speed fluid-driven sheet metal precision forming method according to claim 4, characterized in that: In step S4, the lateral electromagnetic forming coil (14) is simultaneously controlled to discharge so that the lateral driving punch (20) drives the fluid to impact the edge of the sheet material (3).

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