A plate material magnetic high-speed punch forming device and processing method

Abstract

The application belongs to the technical field of plate electromagnetic forming and discloses a plate magnetic high-speed stamping forming device, which comprises a matching concave die and convex die, and a plate to be processed is arranged between the concave die and the convex die; the outer side of the convex die is provided with a guide bin and a supporting block, and the supporting block is located at the bottom of the guide bin; a driving plate is located at the bottom of the convex die and connected with the convex die; an insulating block is fixed with an electromagnetic coil, and the electromagnetic coil is connected with a pulse current loop through a wire; the electromagnetic coil discharges to generate an electromagnetic force to drive the driving plate to move upward so as to drive the convex die to impact the plate to be processed at high speed, and plastic deformation occurs in the thickness direction of the material. A processing method for processing the plate by using the device is also provided. The device and the method have the advantages of high forming efficiency and high forming precision.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic forming technology, specifically to a magnetostrictive high-speed stamping forming apparatus and processing method for sheet metal. Background Technology Stamping is a common plastic forming process. Its principle involves using external force to drive a punch to contact the sheet metal, causing plastic deformation within a certain time. However, after stamping, the unloading of the die and other external forces inevitably cause springback, severely affecting the forming accuracy of the parts. Controlling material springback is a key issue in improving the formability of sheet metal. Current springback control methods mainly include die springback compensation, finite element simulation optimization, manual shaping, or thermoforming. These methods typically suffer from problems such as repeated die trials, die repairs and optimization, long part production cycles, and high production costs.

[0002] CN112091072A discloses a high-efficiency, high-precision magnetic pulse forming apparatus and method for sheet metal. The forming apparatus includes an elastic pad, an electromagnetic coil, and a punch and a die that can move relative to each other to form the sheet metal. The elastic pad is disposed between the punch and the die and covers the forming cavity of the die. The punch and / or die are provided with force-applying components that can be driven by the electromagnetic coil to apply force to the sheet metal in the forming cavity. This invention utilizes the punch and die to stamp the sheet metal, achieving high-precision deformation of the sheet metal; then, electromagnetic force is used to drive the punch to move at high speed, and the elastic pad is used to achieve high-frequency oscillation of the sheet metal within a small range, ultimately reducing springback; after stamping, the unloading of the die and other external forces will inevitably cause springback, which seriously affects the forming accuracy of the parts. How to control material springback is a key issue in improving the formability of sheet metal. Summary of the Invention

[0003] The technical problem to be solved by this invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a high-efficiency, high-precision sheet metal magnetostrictive high-speed stamping forming apparatus and processing method. To solve the above technical problem, the technical solution proposed by this invention is: a sheet metal magnetostrictive high-speed stamping forming apparatus, comprising: The die and punch work together, with the sheet material to be processed placed between them; a guide chamber and a support block are provided on the outside of the punch, with the support block located at the bottom of the guide chamber; The drive plate is located at the bottom of the punch and is connected to the punch. An insulating block is used, on which an electromagnetic coil is fixed. The electromagnetic coil is connected to a pulse current circuit through a wire. The electromagnetic coil discharges to generate electromagnetic force, which causes the drive plate to move upward, thereby driving the punch to impact the sheet material to be processed at high speed, causing plastic deformation in the thickness direction of the material.

[0004] In one embodiment, a heating device is provided inside the die cavity for heating the sheet material to be processed; a heat insulation plate is provided between the guide chamber and the die cavity to prevent heat from being transferred to the guide chamber and the support block.

[0005] In one embodiment, an electrode connected to the guide chamber is also included. The guide chamber and the electrode are connected in series with the electromagnetic coil via a wire. An insulating plate is provided between the die and the guide chamber, and between the guide chamber and the support block.

[0006] In one embodiment, the sheet material to be processed is a composite metal sheet material, which is connected to a guide chamber, and the guide chamber is connected to an electrode and a current circuit is connected through a wire.

[0007] In one embodiment, a connecting plate is provided at the bottom of the insulating block, and the connecting plate is connected to a driving device for pre-deforming and stamping the sheet material to be processed.

[0008] In one embodiment, the top of the punch is a flat punch, and a sealing ring is installed on the top of the flat punch to form a sealing cavity between the top of the flat punch and the sheet material to be processed, and the sealing cavity is filled with a magnetic fluid.

[0009] A processing method for a sheet metal magnetostrictive high-speed stamping forming apparatus, employing the sheet metal magnetostrictive high-speed stamping forming apparatus as described above, includes the following steps: S1: Place the sheet material to be processed between the die and the punch; S2: Connect the pulse current circuit of the electromagnetic coil, discharge to generate electromagnetic force, causing the drive plate to move upward, thereby driving the punch to impact the workpiece at high speed, causing plastic deformation in the thickness direction of the workpiece.

[0010] In one embodiment, the sheet material to be processed is heated by a heating device, or the circuit containing the sheet material to be processed is connected to heat the sheet material.

[0011] In one embodiment, before the pulse current circuit of the electromagnetic coil is turned on, the punch is driven to move upward by a drive device connected to the connecting plate for pre-deformation stamping of the sheet material to be processed.

[0012] In one embodiment, the sheet material to be processed is a large-size sheet material, and the process further includes the following steps: S3: After the pulse current circuit discharge ends, the punch resets, moves and repositions the large sheet metal. S4: Reconnect the pulse current circuit of the electromagnetic coil, discharge to generate electromagnetic force to make the drive plate move upward, thereby driving the punch to impact the workpiece at high speed, causing plastic deformation in the thickness direction of the workpiece. S5: Repeat steps S3 and S4 until the plastic deformation in the thickness direction of the large sheet material is completed.

[0013] Compared with existing technologies, the beneficial effects of this invention are as follows: the bending deformation of sheet metal includes both plastic deformation and elastic deformation. After the load is removed, the plastic deformation of the material is retained, while the elastic deformation allows the material to recover its elasticity due to the release of elastic strain energy. In existing technologies, the sheet metal is first stamped using a punch and die to achieve high-precision deformation; then, electromagnetic force is used to drive the punch to move at high speed, and an elastic pad is used to achieve high-frequency oscillation of the sheet metal within a small range, ultimately reducing springback. This results in large springback and very small plastic deformation. Therefore, the inner layer of the sheet metal is subjected to tangential compressive stress, the outer layer to tangential tensile stress, and the force in the thickness direction is very small, while the absolute value of the stress in the tangential direction is the largest. In this application, however, an electromagnetic coil discharge is directly used to generate electromagnetic force, causing the drive plate to move upward, thereby driving the punch to impact the sheet metal at high speed, resulting in plastic deformation in the thickness direction. The forces on both the inner and outer layers of the sheet metal are tangential compressive stresses, with the force in the thickness direction being the largest, i.e., the absolute value of the stress in the thickness direction is the largest. Compared with the existing electromagnetic stamping technology, the elastic pad is repeatedly compressed, which will apply thickness compressive stress to the sheet metal along the thickness direction, which helps to reduce springback. However, in reality, springback is still uncontrollable, causing the punch to oscillate along the height direction. This application uses a large electromagnetic drive forming, which is a high-speed forming. The punch impacts the sheet metal at high speed and works together with the die, so that the sheet metal thickness is subjected to a large thickness compressive stress. This changes the original bending stress state of the sheet metal from internal pressure and external tension to a unidirectional compressive stress state or a certain stress state is greatly reduced, thereby making the material plastic dissipation energy greater and the material thickness direction plastic deformation occurs. Therefore, the sheet metal springback is smaller and the forming accuracy is higher. The device and processing method of this application also have the following advantages: (1) Short forming time, which can make the material form in a very short time. (2) High forming accuracy. The method of this invention is a high-speed forming method, which can effectively reduce springback, improve the forming accuracy of the material, and reduce the time of repeated mold trials and mold repairs. (3) Only a single mold is required. For different parts, only the corresponding punches and dies need to be machined, which facilitates mass automated production and helps reduce production costs. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of a sheet metal magnetostrictive high-speed stamping forming apparatus according to one embodiment. Figure 2 This is a schematic diagram of a sheet metal magnetostrictive high-speed stamping forming apparatus according to one embodiment. Figure 3This is a schematic diagram of a sheet metal magnetostrictive high-speed stamping forming apparatus according to one embodiment. Figure 4 This is a schematic diagram of a sheet metal magnetostrictive high-speed stamping forming apparatus according to one embodiment. Figure 5 This is a schematic diagram of a sheet metal magnetostrictive high-speed stamping forming apparatus according to one embodiment. Figure 6 This is a schematic diagram of a sheet metal magnetostrictive high-speed stamping forming apparatus according to one embodiment. Figure 7 This is a schematic diagram of a sheet metal magnetostrictive high-speed stamping forming apparatus according to one embodiment. Figure 8 This is a schematic diagram of a sheet metal magnetostrictive high-speed stamping forming apparatus according to one embodiment. Figure 9 This is a schematic diagram of a sheet metal magnetostrictive high-speed stamping forming apparatus according to one embodiment. Figure 10 This is a schematic diagram of a sheet metal magnetostrictive high-speed stamping forming apparatus according to one embodiment. Figure 11 This is a schematic diagram of a large-size sheet metal forming apparatus according to one embodiment of a sheet metal magnetostrictive high-speed stamping forming device.

[0016] Figure descriptions: 1: Bolt; 2: Upper mold base; 3: Die; 4: Sheet metal; 5: Punch; 6: Guide chamber; 7: Support block; 8: Drive plate; 9: Coil; 10: Insulating block; 11: Lower mold base; 12: Connecting plate; 13: Guide sleeve; 14: Guide post; 15: Heating rod; 16: Heat insulation plate; 17: Insulating plate; 18: Electrode; 19: Wire; 22: Wall panel; 23: Wall panel filler; 24: Fluid; 25: Flat punch; 26: Sealing ring; 27: Large sheet metal. Detailed Implementation

[0017] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0018] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0019] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0020] Please see Figure 1-11One embodiment of a sheet metal magnetostrictive high-speed stamping forming apparatus includes a die 3 and a punch 5 used in conjunction, with the sheet metal to be processed placed between the die 3 and the punch 5. Specifically, an upper die holder 2 is provided above the die 3, and the upper die holder 2 and the die 3 are connected by bolts 1. The upper die holder 2 and the lower die holder 11 are positioned by guide sleeves and guide posts 14. An electromagnetic coil 9 and an insulating block 10 are placed below the punch 5, and a drive plate 8 is located at the bottom of the punch 5 and connected to the punch 5. The drive plate 8 is located between the insulating block 10 and the punch 5. The electromagnetic coil 9 is fixed on the insulating block 10, and the electromagnetic coil 9 is connected to a pulse current circuit through a wire. Specifically, in one embodiment, the insulating block 10 can be an insulating material block such as an epoxy block, nylon block, or polytetrafluoroethylene block. The electromagnetic coil 9 discharges to generate electromagnetic force, causing the drive plate to move upward, thereby driving the punch to impact the sheet metal to be processed at high speed, causing plastic deformation in the thickness direction of the material. A connecting plate 12 is provided at the bottom of the electromagnetic coil 9 and the insulating block 10. The punch 5 and the drive plate 8 are connected together by bolts, welding, or adhesive, and are placed above the electromagnetic coil 9. A guide chamber 6 and a support block 7 are provided on the outer side of the punch 5. The support block 7 is placed above the lower die holder 11, and the guide chamber 6 is placed above the support block 7. Preferably, in one embodiment, when pre-deformation stamping of the sheet metal is required, a lower oil cylinder, air cylinder, or other drive device of the press is connected below the connecting plate 12.

[0021] Please see reading Figure 2 Specifically, in one embodiment, a heating device 15 is provided inside the die cavity 3. In this embodiment, the heating device 15 is a heating rod. In other embodiments, it may be a heating tube, a heating plate, etc., used to heat the sheet material to be processed. A heat insulation plate 16 is provided between the guide chamber 6 and the die cavity 3 to prevent heat from being transferred to the guide chamber 6 and the support block 7.

[0022] Please see reading Figure 3 In one embodiment, an electrode 18 connected to the guide chamber 6 is also included. The guide chamber 6 and the electrode 18 are connected in series with the electromagnetic coil 9 via a wire 19. An insulating plate 17 is provided between the die 3 and the guide chamber 6, and between the guide chamber 6 and the support block 7. Since the electrode 18 and the electromagnetic coil 9 are connected in series, a pulsed current can be applied to the sheet metal to be processed. Utilizing the electroplastic effect of the current, the plastic deformation capacity of the material is improved and springback is reduced. The reduction of springback by current is the combined effect of the Joule heating effect and the electrical effect. The current can increase the material temperature, thereby softening the material, reducing the flow stress of the material, and decreasing springback.

[0023] Please see reading Figure 4In another embodiment, the sheet metal to be processed is connected to the guide chamber 6, and the guide chamber 6 is connected to the electrode 18 and to the current circuit via the wire 19. In this case, the current circuit and the circuit containing the electromagnetic coil 9 are two independent current circuits. During use, the current circuit containing the sheet metal to be processed is connected first, and then the pulse current circuit containing the electromagnetic coil 9 is connected. In this embodiment, the sheet metal to be processed is a composite metal sheet or other conductive metal sheet.

[0024] Under the aforementioned heating conditions using heating devices or electric heating, the sheet metal's deformability is enhanced, and high-speed forming reduces springback; both factors work together to improve forming accuracy. Specifically, for titanium and magnesium alloys, heating is performed to the phase transformation temperature. For materials such as aluminum alloys, heating is performed to the failure temperature. This heating allows the device to process sheets of high-strength alloys with greater hardness, such as titanium and magnesium alloys.

[0025] Please see Figure 5 In one embodiment, the sheet material to be processed is a wall panel, and wall panel filler 23 is provided between adjacent ribs at the bottom of the wall panel 22. This embodiment differs only in the structure of the sheet material.

[0026] Please see Figure 6 In one embodiment, the top of the punch 5 is a flat punch 25, and a sealing ring 26 is installed on the top of the flat punch 25, forming a sealing cavity 24 between the top of the flat punch 25 and the sheet material to be processed. The sealing cavity is filled with a magnetic fluid. Commonly used magnetic fluids include Fe, Ni, and Co as magnetic particles, water, organic solvents, and oil as the base liquid, and oleic acid as an activator to prevent agglomeration. Using a magnetic fluid as the transfer medium, the sheet material exhibits better forming uniformity due to the removal of the shape constraints of the die 3 and the fluidity properties of the liquid.

[0027] Based on the same inventive concept, this application also provides a processing method for a sheet metal magnetostrictive high-speed stamping forming apparatus, which employs the sheet metal magnetostrictive high-speed stamping forming apparatus as described above, and includes the following steps: S1: Place the sheet material to be processed between the concave die 3 and the convex die 5; S2: Connect the pulse current circuit of the electromagnetic coil 9, discharge to generate electromagnetic force, causing the drive plate 8 to move upward, thereby driving the punch 5 to impact the workpiece at high speed, causing plastic deformation in the thickness direction of the workpiece.

[0028] In one embodiment, the sheet material to be processed is heated by a heating device 15, or the circuit containing the sheet material to be processed is connected to heat the sheet material.

[0029] In one embodiment, when the sheet material to be processed is a high-strength material, such as titanium alloy or high-strength aluminum alloy, before the pulse current circuit of the electromagnetic coil 9 is turned on, the punch can be driven upward by a drive device connected to the connecting plate 12 for pre-deformation stamping of the sheet material to be processed.

[0030] Preferably, the sheet metal can also be softened by heating, which generates dislocations in the sheet metal. The presence of dislocations increases the strength of the material. Using a heating device or current heating can reduce the dislocation density, softening the material and facilitating high-speed electromagnetically driven forming. Both high-speed forming and current (heating) help reduce springback. The reduction of springback by current is due to the combined effects of Joule heating and electrical effects. Current increases the material temperature, softening the material, reducing flow stress, and decreasing springback.

[0031] In one embodiment, when the sheet material to be processed is a large-size sheet material 27, please refer to [reference needed]. Figure 7-11 In addition to the steps described above, the following steps are also included: S3: After the pulse current circuit discharge ends, the punch 5 is reset, and the large-size sheet metal 27 is moved and repositioned. S4: Reconnect the pulse current circuit of electromagnetic coil 9, discharge to generate electromagnetic force to make the drive plate move upward, thereby driving the punch to impact the plate to be processed at high speed, and the plate to be processed undergoes plastic deformation in the thickness direction. S5: Repeat steps S3 and S4 until the plastic deformation in the thickness direction of the large sheet material is completed.

[0032] Compared with existing technologies, the beneficial effects of this invention are as follows: the bending deformation of sheet metal includes both plastic deformation and elastic deformation. After the load is removed, the plastic deformation of the material is retained, while the elastic deformation allows the material to recover its elasticity due to the release of elastic strain energy. In existing technologies, the sheet metal is first stamped using a punch and die to achieve high-precision deformation; then, electromagnetic force is used to drive the punch to move at high speed, and an elastic pad is used to achieve high-frequency oscillation of the sheet metal within a small range, ultimately reducing springback. This results in large springback and very small plastic deformation. Therefore, the inner layer of the sheet metal is subjected to tangential compressive stress, the outer layer to tangential tensile stress, and the force in the thickness direction is very small, while the absolute value of the stress in the tangential direction is the largest. In this application, however, an electromagnetic coil discharge is directly used to generate electromagnetic force, causing the drive plate to move upward, thereby driving the punch to impact the sheet metal at high speed, resulting in plastic deformation in the thickness direction. The forces on both the inner and outer layers of the sheet metal are tangential compressive stresses, with the force in the thickness direction being the largest, i.e., the absolute value of the stress in the thickness direction is the largest. Compared with the existing electromagnetic stamping technology, the elastic pad is repeatedly compressed, which will apply thickness compressive stress to the sheet metal along the thickness direction, which helps to reduce springback. However, in reality, springback is still uncontrollable, causing the punch to oscillate along the height direction. This application uses a large electromagnetic drive forming, which is a high-speed forming. The punch impacts the sheet metal at high speed and works together with the die, so that the sheet metal thickness is subjected to a large thickness compressive stress. This changes the original bending stress state of the sheet metal from internal pressure and external tension to a unidirectional compressive stress state or a certain stress state is greatly reduced, thereby making the material plastic dissipation energy greater and the material thickness direction plastic deformation occurs. Therefore, the sheet metal springback is smaller and the forming accuracy is higher. The device and processing method of this application also have the following advantages: (1) Short forming time, which can make the material form in a very short time. (2) High forming accuracy. The method of this invention is a high-speed forming method, which can effectively reduce springback, improve the forming accuracy of the material, and reduce the time of repeated mold trials and mold repairs. (3) Only a single mold is required. For different parts, only the corresponding punches and dies need to be machined, which facilitates mass automated production and helps reduce production costs.

Claims

1. A processing method for a sheet metal magnetostrictive high-speed stamping forming device, characterized in that, A sheet metal magnetostrictive high-speed stamping forming device is employed, comprising: a die and a punch used in conjunction, with the sheet metal to be processed placed between the die and the punch; a guide chamber and a support block are provided on the outside of the punch, with the support block located at the bottom of the guide chamber; a drive plate located at the bottom of the punch and connected to the punch; an insulating block with an electromagnetic coil fixed on it, the electromagnetic coil being connected to a pulse current circuit via a wire; the electromagnetic coil discharges to generate electromagnetic force, causing the drive plate to move upward, thereby driving the punch to impact the sheet metal at high speed, resulting in plastic deformation in the thickness direction of the material; the forces on the inner and outer layers of the sheet metal are both tangential compressive stresses, with the maximum force and the largest absolute value of the stress in the thickness direction; it also includes electrodes connected to the guide chamber, the guide chamber and the electrodes being connected in series with the electromagnetic coil via wires; insulating plates are provided between the die and the guide chamber, and between the guide chamber and the support block; a lower hydraulic cylinder or pneumatic cylinder of a press is connected below the connecting plate; The sheet material to be processed is a large-sized sheet material, and the process includes the following steps: S1: Place the sheet material to be processed between the die and the punch; before the pulse current circuit of the electromagnetic coil is turned on, drive the punch to move upward through the drive device connected to the connecting plate for pre-deformation stamping of the sheet material to be processed; S2: The pulse current circuit of the electromagnetic coil is turned on, and the discharge generates electromagnetic force, which makes the drive plate move upward, thereby driving the punch to impact the workpiece at high speed, causing plastic deformation in the thickness direction of the workpiece; S3: After the pulse current circuit discharge ends, the punch resets, moves and repositions the large sheet metal. S4: Reconnect the pulse current circuit of the electromagnetic coil, discharge to generate electromagnetic force to make the drive plate move upward, thereby driving the punch to impact the workpiece at high speed, causing plastic deformation in the thickness direction of the workpiece. S5: Repeat steps S3 and S4 until the plastic deformation in the thickness direction of the large sheet material is completed.

2. The processing method according to claim 1, characterized in that, The material to be processed is heated by a heating device, or the circuit containing the material to be processed is connected to heat the material.

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