Plate magnetic high-speed stamping forming device and machining method

Abstract

The invention belongs to the technical field of plate electromagnetic forming, and discloses a plate magnetic high-speed stamping forming device which comprises a female die and a male die used in cooperation, and a plate to be machined is arranged between the female die and the male die; a guide bin and a supporting block are arranged on the outer side of the male die. The supporting block is located at the bottom of the guide bin. The driving plate is located at the bottom of the male die and connected with the male die; the insulating block is fixedly provided with an electromagnetic coil, and the electromagnetic coil is connected with the pulse current loop through a wire; the electromagnetic coil discharges to generate electromagnetic force to enable the driving plate to move upwards so as to drive the male die to impact a to-be-machined plate at a high speed, and plastic deformation occurs in the material thickness direction. The invention further provides a machining method for machining the plate through the device. The device and the method have the advantages of high forming efficiency and high forming precision.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic forming, and in particular to a plate magnetically induced high-speed stamping forming device and a processing method. Background Art Stamping is a common plastic processing technology. Its principle is to use external force to drive the punch to contact the sheet material, so that the sheet material undergoes plastic deformation within a certain period of time. However, external forces such as unloading the mold after stamping 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 the sheet metal. At present, the main methods for springback control include mold springback compensation, finite element simulation optimization, manual correction or warm forming, etc. These methods usually have problems such as repeated mold trials, mold repairs and optimization of mold size, long part production cycle and high production cost.

[0002] CN112091072A discloses a high-efficiency and high-precision magnetic pulse forming device and forming method for sheet metal, wherein the forming device comprises an elastic pad, an electromagnetic coil, and a punch and a die that can move relative to each other to form the sheet metal, wherein the elastic pad is arranged between the punch and the die and covers the forming cavity of the die, and the punch and / or the die are provided with a force-applying member that can be driven by the electromagnetic coil to apply force to the sheet metal in the forming cavity. The present invention uses a punch and a die to stamp the sheet metal to achieve 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 in a small range, and finally reduce springback; after stamping, external forces such as unloading the mold will inevitably cause springback, which seriously affects the forming accuracy of the parts. How to control the springback of the material is a key issue in improving the formability of the sheet metal. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide a high-efficiency and high-precision sheet metal magnetic high-speed stamping forming device and processing method. In order to solve the above technical problems, the technical solution proposed by the present invention is: a sheet metal magnetic high-speed stamping forming device, comprising: A concave die and a convex die are used in combination, and the sheet material to be processed is placed between the concave die and the convex die; a guide bin and a support block are provided on the outer side of the convex die, and the support block is located at the bottom of the guide bin; A driving plate is located at the bottom of the punch and connected to the punch; An insulating block is fixed with an electromagnetic coil, which is connected to a pulse current loop through a wire; the electromagnetic coil discharges to generate an electromagnetic force that 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 in the die to heat the sheet material to be processed; a heat insulation plate is provided between the guide bin and the die to prevent heat from being transferred to the guide bin and the support block.

[0005] In one embodiment, it also includes an electrode connected to the guide bin, the guide bin and the electrode are connected in series with the electromagnetic coil through a wire, and an insulating plate is provided between the die and the guide bin, and between the guide bin and the support block.

[0006] In one embodiment, the sheet material to be processed is a composite metal sheet material, the sheet material to be processed is connected to a guide bin, and the guide bin is connected to an electrode and is connected to a current loop 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 performing pre-deformation stamping on the sheet material to be processed.

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

[0009] A processing method of a plate magnetic high-speed stamping forming device, using the plate magnetic high-speed stamping forming device as described above, comprises the following steps: S1: Place the sheet material to be processed between the concave die and the convex die; S2: The pulse current loop of the electromagnetic coil is connected, and the discharge generates electromagnetic force to move the driving plate upward, thereby driving the punch to impact the sheet material to be processed at high speed, and plastic deformation occurs in the thickness direction of the sheet material to be processed.

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

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

[0012] In one embodiment, the sheet material to be processed is a large-sized sheet material, and the process further includes the following steps: S3: After the pulse current loop discharges, the punch is reset, and the large-size sheet is moved and repositioned; S4: The pulse current loop of the electromagnetic coil is connected again, and the discharge generates electromagnetic force to make the driving plate move upward, thereby driving the punch to impact the sheet material to be processed at high speed, and the sheet material to be processed undergoes plastic deformation in the thickness direction; S5: Repeat steps S3 and S4 until the plastic deformation of the large-size sheet in the thickness direction is completed.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: the bending deformation of the sheet includes plastic deformation and elastic deformation. After the load is removed, the plastic deformation of the material is retained, and the elastic deformation causes the material to recover elastically due to the release of elastic strain energy. In the prior art, the sheet is first punched with a convex and concave die to achieve high-precision deformation of the sheet; then electromagnetic force is used to drive the punch to move at high speed, and the high-frequency oscillation of the sheet in a small range is achieved with the help of an elastic pad, and finally the rebound is reduced. The sheet has large rebound and small plastic deformation. Therefore, the inner layer of the sheet is subjected to tangential compressive stress, the outer layer is subjected to tangential tensile stress, the force in the thickness direction is very small, and the absolute value of the stress in the tangential direction is the largest. In the present application, the electromagnetic coil is directly used to discharge to generate electromagnetic force to make the driving plate move upward, thereby driving the punch to impact the sheet to be processed at high speed, and plastic deformation occurs in the thickness direction of the material. The forces on the inner and outer layers of the sheet are both tangential compressive stress, and the force in the thickness direction is the largest, that is, the absolute value of the stress in the thickness direction is the largest. Compared with the electromagnetic stamping of the prior art, after the elastic pad is repeatedly compressed, the sheet metal will be subjected to a thickness compressive stress in the direction of the sheet metal thickness, which helps to reduce springback, but in fact the springback cannot be controlled, causing the punch to oscillate in the height direction. The present application uses a larger electromagnetic drive to form a high-speed forming method. The punch hits the sheet metal at high speed and acts together with the die, so that the thickness of the sheet metal is subjected to a huge thickness compressive stress, so that the original bending stress state of the sheet metal changes 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 larger and plastic deformation occurs in the thickness direction of the material. Therefore, the sheet metal rebounds less and the forming accuracy is higher. The device and processing method of the present application also have the following advantages: (1) The forming time is short, and the material can be formed in a very short time. (2) The forming accuracy is high. The method of the present invention belongs to a high-speed forming method, which can effectively reduce springback, improve the accuracy of material forming, 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 processed, which facilitates mass automated production and helps reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 It is a schematic structural diagram of a plate material magnetic high-speed stamping forming device according to one embodiment; Figure 2 It is a schematic structural diagram of a plate material magnetic high-speed stamping forming device according to one embodiment; Figure 3It is a schematic structural diagram of a plate material magnetic high-speed stamping forming device according to one embodiment; Figure 4 It is a schematic structural diagram of a plate material magnetic high-speed stamping forming device according to one embodiment; Figure 5 It is a schematic structural diagram of a plate material magnetic high-speed stamping forming device according to one embodiment; Figure 6 It is a schematic structural diagram of a plate material magnetic high-speed stamping forming device according to one embodiment; Figure 7 It is a schematic structural diagram of a plate material magnetic high-speed stamping forming device according to one embodiment; Figure 8 It is a schematic structural diagram of a plate material magnetic high-speed stamping forming device according to one embodiment; Fig. 9 It is a schematic structural diagram of a plate material magnetic high-speed stamping forming device according to one embodiment; Fig.10 It is a schematic structural diagram of a plate material magnetic high-speed stamping forming device according to one embodiment; Fig.11 It is a schematic diagram of large-size sheet metal forming by a sheet metal magnetic high-speed stamping forming device according to one embodiment.

[0016] Description of the drawings: 1: Bolts; 2. Upper mold frame; 3. Die; 4. Sheet material; 5. Punch; 6. Guide bin; 7. Support block; 8. Drive plate; 9. Coil; 10. Insulation block; 11. Lower mold frame; 12. Connecting plate; 13. Guide sleeve; 14. Guide column; 15. Heating rod; 16. Insulation board; 17. Insulation board; 18. Electrode; 19. Wire; 22. Wall panel; 23. Wall panel filler; 24. Fluid; 25. Flat convex die; 26. Sealing ring; 27. Large-size sheet material. DETAILED DESCRIPTION

[0017] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0018] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

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

[0020] See also Figure 1-11, a plate magneto-induced high-speed stamping forming device of one embodiment includes a die 3 and a punch 5 used in combination, and the sheet material to be processed is placed between the die 3 and the punch 5. Specifically, an upper die frame 2 is provided above the die 3, and the upper die frame 2 and the die 3 are connected by a bolt 1. The upper die frame 2 and the lower die frame 11 are positioned by a guide sleeve 13 and a guide column 14. The electromagnetic coil 9 and the insulating block 10 are placed below the punch 5, and the 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 the pulse current loop through a wire. Specifically, in one embodiment, the insulating block 10 can be an insulating material block such as an epoxy block, a nylon block, a polytetrafluoroethylene block, etc. The electromagnetic coil 9 discharges to generate an electromagnetic force to cause the drive plate to move upward, thereby driving the punch to impact the sheet material to be processed at a high speed, and plastic deformation occurs 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 driving plate 8 are bolted, welded or glued together and placed above the electromagnetic coil 9. The outer side of the punch 5 is provided with a guide bin 6 and a support block 7. The support block 7 is placed above the lower die frame 11, and the guide bin 6 is placed above the support block 7. Preferably, in one embodiment, when it is necessary to pre-deform and stamp the sheet material, the lower oil cylinder, air cylinder or other driving device of the press is connected below the connecting plate 12.

[0021] See Read Figure 2 Specifically, in one embodiment, a heating device 15 is provided in the die 3. In this embodiment, the heating device 15 is a heating rod. In other embodiments, the heating device 15 may be a heating tube, a heating plate, etc., for heating the sheet to be processed. A heat insulation board 16 is provided between the guide bin 6 and the die 3 to prevent heat from being transferred to the guide bin 6 and the support block 7.

[0022] See Read Figure 3 In one embodiment, it also includes an electrode 18 connected to the guide bin 6. The guide bin 6 and the electrode 18 are connected in series with the electromagnetic coil 9 through a wire 19. An insulating plate 17 is provided between the die 3 and the guide bin 6, and between the guide bin 6 and the support block 7. Since the electrode 18 and the electromagnetic coil 9 are connected in series, a pulse current can be applied to the sheet to be processed. The electroplastic effect of the current is utilized to improve the plastic deformation ability of the material and reduce the rebound. Passing current to reduce the rebound is the combined effect of the Joule heat effect and the electrical effect. Passing current can increase the material temperature, so the material softens, the flow stress of the material is reduced, and the rebound is reduced.

[0023] See Read Figure 4In another embodiment, the sheet material to be processed is connected to the guide bin 6, and the guide bin 6 is connected to the electrode 18, and is connected to the current loop through the wire 19. At this time, the current loop and the loop where the electromagnetic coil 9 is located are two independent current loops. When in use, the current loop where the sheet material to be processed is connected first, and then the pulse current loop where the electromagnetic coil 9 is located is connected. In this embodiment, the sheet material to be processed is a composite metal sheet material or other conductive metal sheet material.

[0024] Under the above-mentioned heating conditions using a heating device or electric heating, the deformation ability of the sheet is improved, and high-rate forming can reduce springback. The two work together to improve the forming accuracy. Specifically, for titanium alloy and magnesium alloy materials, heat to the phase transition temperature. For aluminum alloy and other materials, heat to the failure temperature. By heating, the device can be used to process high-strength alloys such as titanium alloys and magnesium alloys with higher hardness.

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

[0026] See also 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. A sealed cavity 24 is formed between the top of the flat punch 25 and the sheet material to be processed, and a magnetic fluid is filled in the sealed cavity. The magnetic fluid generally uses Fe, Ni, Co, etc. as magnetic particles, water, organic solvents, oils, etc. as base liquids, and oleic acid, etc. as active agents to prevent agglomeration. The use of magnetic fluid as a transmission medium can remove the restrictions on the shape of the die 3 and the fluidity of the liquid, so that the sheet material has better forming uniformity.

[0027] Based on the same inventive concept, the present application also provides a processing method of a plate magnetic high-speed stamping forming device, using the plate magnetic high-speed stamping forming device as described above, comprising the steps of: S1: placing the sheet material to be processed between the die 3 and the punch 5; S2: The pulse current loop of the electromagnetic coil 9 is connected, and the discharge generates electromagnetic force to move the driving plate 8 upward, thereby driving the punch 5 to impact the sheet material to be processed at high speed, and plastic deformation occurs in the thickness direction of the sheet material to be processed.

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

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

[0030] Preferably, the sheet material can also be heated and softened by heating, dislocations are generated in the sheet material, and the presence of dislocations will increase the strength of the material. The sheet material can be heated by a heating device or by passing current to reduce the dislocation density and soften the material, which is conducive to electromagnetically driven high-rate forming of the sheet material. High-rate forming and passing current (heating) are both conducive to reducing springback. Passing current to reduce springback is the combined effect of Joule's thermal effect and electrical effect. Passing current can increase the material temperature, so the material softens, the material's flow stress is reduced, and the springback is reduced.

[0031] In one embodiment, when the sheet material to be processed is a large-sized sheet material 27, please refer to Figure 7-11 , based on the above steps, further comprising the following steps: S3: After the pulse current loop discharges, the punch 5 is reset, and the large-size sheet material 27 is moved and repositioned; S4: The pulse current loop of the electromagnetic coil 9 is connected again, and the discharge generates an electromagnetic force to move the driving plate upward, thereby driving the punch to impact the sheet material to be processed at high speed, and the sheet material to be processed undergoes plastic deformation in the thickness direction; S5: Repeat steps S3 and S4 until the plastic deformation of the large-size sheet in the thickness direction is completed.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: the bending deformation of the sheet includes plastic deformation and elastic deformation. After the load is removed, the plastic deformation of the material is retained, and the elastic deformation causes the material to recover elastically due to the release of elastic strain energy. In the prior art, the sheet is first punched with a convex and concave die to achieve high-precision deformation of the sheet; then electromagnetic force is used to drive the punch to move at high speed, and the high-frequency oscillation of the sheet in a small range is achieved with the help of an elastic pad, and finally the rebound is reduced. The sheet has large rebound and small plastic deformation. Therefore, the inner layer of the sheet is subjected to tangential compressive stress, the outer layer is subjected to tangential tensile stress, the force in the thickness direction is very small, and the absolute value of the stress in the tangential direction is the largest. In the present application, the electromagnetic coil is directly used to discharge to generate electromagnetic force to make the driving plate move upward, thereby driving the punch to impact the sheet to be processed at high speed, and plastic deformation occurs in the thickness direction of the material. The forces on the inner and outer layers of the sheet are both tangential compressive stress, and the force in the thickness direction is the largest, that is, the absolute value of the stress in the thickness direction is the largest. Compared with the electromagnetic stamping of the prior art, after the elastic pad is repeatedly compressed, the sheet metal will be subjected to a thickness compressive stress in the direction of the sheet metal thickness, which helps to reduce springback, but in fact the springback cannot be controlled, causing the punch to oscillate in the height direction. The present application uses a larger electromagnetic drive to form a high-speed forming method. The punch hits the sheet metal at high speed and acts together with the die, so that the thickness of the sheet metal is subjected to a huge thickness compressive stress, so that the original bending stress state of the sheet metal changes 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 larger and plastic deformation occurs in the thickness direction of the material. Therefore, the sheet metal rebounds less and the forming accuracy is higher. The device and processing method of the present application also have the following advantages: (1) The forming time is short, and the material can be formed in a very short time. (2) The forming accuracy is high. The method of the present invention belongs to a high-speed forming method, which can effectively reduce springback, improve the accuracy of material forming, 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 processed, which facilitates mass automated production and helps reduce production costs.

Claims

1. A plate magnetic high-speed stamping forming device, comprising: A concave die and a convex die are used in combination, and the sheet material to be processed is placed between the concave die and the convex die; a guide bin and a support block are provided on the outer side of the convex die, and the support block is located at the bottom of the guide bin; A driving plate is located at the bottom of the punch and connected to the punch; An insulating block is fixed with an electromagnetic coil, which is connected to a pulse current loop through a wire; the electromagnetic coil discharges to generate an electromagnetic force to move the driving plate 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.

2. The plate magneto-induced high-speed stamping forming device according to claim 1 is characterized in that: A heating device is provided in the die to heat the sheet material to be processed; a heat insulation board is provided between the guide bin and the die to prevent heat from being transferred to the guide bin and the support block.

3. The plate magneto-induced high-speed stamping forming device according to claim 1, characterized in that: It also includes an electrode connected to the guide bin. The guide bin and the electrode are connected in series with the electromagnetic coil through a wire. Insulating plates are provided between the die and the guide bin, and between the guide bin and the support block.

4. The plate material magnetic high-speed stamping forming device according to claim 1, characterized in that: The sheet material to be processed is a composite metal sheet material, which is connected to a guide bin, and the guide bin is connected to an electrode, and is connected to a current loop through a wire.

5. The sheet material magnetic high-speed stamping forming device according to claim 3 or 4, characterized in that: A connecting plate is provided at the bottom of the insulating block, and the connecting plate is connected to a driving device for performing pre-deformation stamping on the sheet material to be processed.

6. The plate material magnetic high-speed stamping forming device according to claim 1, characterized in that: The top of the punch is a flat punch, a sealing ring is installed on the top of the flat punch, and a sealed cavity is formed between the top of the flat punch and the sheet material to be processed, and a magnetic fluid is filled in the sealed cavity.

7. A processing method of a plate magneto-induced high-speed stamping forming device, characterized in that: The plate magneto-induced high-speed stamping forming device according to any one of claims 1 to 6 comprises the following steps: S1: Place the sheet material to be processed between the concave die and the convex die; S2: The pulse current loop of the electromagnetic coil is connected, and the discharge generates electromagnetic force to move the driving plate upward, thereby driving the punch to impact the sheet material to be processed at high speed, and plastic deformation occurs in the thickness direction of the sheet material to be processed.

8. The processing method according to claim 7, characterized in that: The sheet material to be processed is heated by a heating device, or the circuit where the sheet material to be processed is connected is used to heat the sheet material to be processed.

9. The processing method according to claim 7, characterized in that: Before the pulse current loop of the electromagnetic coil is connected, the punch is driven to move upward by a driving device connected to the connecting plate to perform pre-deformation stamping on the sheet material to be processed.

10. The processing method according to claim 7, characterized in that: The sheet material to be processed is a large-size sheet material, and the steps include: S3: After the pulse current loop discharges, the punch is reset, and the large-size sheet is moved and repositioned; S4: The pulse current loop of the electromagnetic coil is connected again, and the discharge generates electromagnetic force to make the driving plate move upward, thereby driving the punch to impact the sheet material to be processed at high speed, and the sheet material to be processed undergoes plastic deformation in the thickness direction; S5: Repeat steps S3 and S4 until the plastic deformation of the large-size sheet in the thickness direction is completed.

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