An electromagnetic forming method and device based on a three-coil dual-power supply board

Abstract

An electromagnetic forming method and device based on a three-coil dual-power supply board. The method includes the following steps: S1. Clamp the edge of the metal board to fix the metal board, place a background magnetic field coil and an eddy current coil above the metal board, and place an improvement coil below the metal board; S2. Connect the background magnetic field coil to a long-pulse-width power supply system to generate a background magnetic field; S3. When the long-pulse-width pulse current reaches the peak value, connect the eddy current coil and the improvement coil in series and then connect them to a short-pulse-width power supply system, so that the board in the magnetic field is subjected to an upward Lorentz force and deforms upward. The present invention realizes a new scheme for forming a board by the cooperation of three groups of coils under the action of attractive electromagnetic force. By controlling the discharge voltage and the capacitor capacitance value in the three groups of power supply devices, the eddy current and the magnetic field can be flexibly regulated, and the diversified loading of the Lorentz force can be realized.

Description

Technical Field

[0001] The present invention relates to the field of metal forming manufacturing, and particularly to an electromagnetic forming method and device for a three-coil dual-power supply plate Background Art

[0002] Electromagnetic forming technology is mainly applied to the processing of plates and pipe fittings. The electromagnetic force in the process of plate electromagnetic forming can be divided into repulsive electromagnetic force and attractive electromagnetic force. The present invention mainly uses the attractive electromagnetic force to process and manufacture metal plates. The existing attractive electromagnetic forming technology for plates has the problem of low energy utilization rate, resulting in an unsatisfactory forming depth of the plates. Current patents for attractive electromagnetic forming of plates such as Patent CN201911303862.0 - A method and device for attractive forming of plates using a dual-coil power supply structure. This device mainly uses two sets of solenoid coils. A long-pulse-width pulsed current is first passed through the first set of coils to form a background magnetic field; immediately after the long-pulse-width current passed through the first set of coils reaches its peak value, a short-pulse-width current is passed through the second set of coils, and a circumferential induced eddy current is generated in the plate under the influence of the magnetic field; finally, the plate with the induced circumferential eddy current is under the action of the Lorentz force and cooperates with a forming die for controllable rapid forming. This method broadens the forming scheme for attractive plates and solves the problem of a single electromagnetic forming scheme for attractive plates. However, the energy utilization rate of the attractive electromagnetic force generated by this method is relatively low, resulting in an unsatisfactory forming depth of the plates. The present invention introduces an improved coil on the basis of the original dual-coil attractive electromagnetic forming. The magnetic field and eddy current generated after passing a short-pulse-width current effectively compensate for the intensity of the original background magnetic field and the density of the eddy current on the plate, making the electromagnetic force during the forming process greater, the forming effect of the plate better, and the energy utilization rate higher

[0003] In the existing attractive forming technology for plates, the dual-frequency current method and the dual-coil dual-power supply attractive electromagnetic forming technology both have obvious deficiencies: 1. Since the dual-frequency current method requires passing two large pulsed currents in opposite directions through a single coil, this will have a huge impact on the stability of the coil structure and shorten its service life. At the same time, the two sets of power supply devices passing through the coil need to strictly control their discharge parameters to match the corresponding electromagnetic force effect, which also makes the low energy utilization rate of the discharge system an inevitable defect of this scheme. 2. In the electromagnetic forming scheme of the dual-coil dual-power supply, since the forming process involves two discharge coils, the problems of eddy current competition and magnetic field competition will follow. The most direct impact of these two is the increase in energy loss, which in turn makes the forming effect of the plate worse, and ultimately severely restricts the energy utilization rate of the entire system Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an electromagnetic forming method and device based on a three-coil dual-power supply plate. By introducing an improvement coil at the axial positions of the original background magnetic field coil and the induction eddy current coil, after the long-pulse-width current applied to the background magnetic field coil reaches the peak value, a short-pulse-width current is simultaneously applied to the induction eddy current coil and the improvement coil, so that the overall area of the magnetic field where the plate is located is subjected to an attractive electromagnetic force. At this moment, due to the addition of the improvement coil, the situation where the original background magnetic field intensity and the eddy current density in the plate are weakened due to magnetic field competition and eddy current competition is improved, and the energy utilization rate of the system is increased. At the same time, the electromagnetic force generated by the improvement coil can promote each other with the original attractive force, generating a greater electromagnetic force, thereby enabling the plate to achieve a better forming effect.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: an electromagnetic forming method based on a three-coil dual-power supply plate, comprising the following steps:

[0006] S1. Clamp the edge of the metal plate to fix the metal plate, place a background magnetic field coil and an eddy current coil above the metal plate, and place an improvement coil below the metal plate;

[0007] S2. Connect the background magnetic field coil to a long-pulse-width power supply system to generate a background magnetic field;

[0008] S3. When the long-pulse-width pulse current reaches the peak value, connect the eddy current coil and the improvement coil in series and then connect them to a short-pulse-width power supply system, so that the plate in the magnetic field is subjected to an upward Lorentz force and deforms upward.

[0009] Preferably, the current directions of the eddy current coil and the background magnetic field coil are opposite, and the current directions of the eddy current coil and the improvement coil are the same.

[0010] Preferably, it further includes:

[0011] S4. Conduct a comparison of the forming effects. If the forming standard is not reached, return to S2; otherwise, end.

[0012] Preferably, in S1, the pressure for clamping the metal plate is set to 1 to 1.5 MPa.

[0013] Preferably, before step S1, the metal plate is annealed.

[0014] Preferably, the eddy current coil is placed above the forming area.

[0015] An electromagnetic forming device based on a three-coil dual-power supply plate includes an upper coil skeleton for arranging a background magnetic field coil and an eddy current coil, and a lower coil skeleton for arranging an improvement coil; an upper clamping part is provided at the lower end of the upper coil skeleton, the lower coil skeleton is arranged in the lower clamping part, and the upper clamping part and the lower clamping part are used to clamp the metal plate.

[0016] Preferably, the background magnetic field coil is connected to a long pulse-width power supply system, and the eddy current coil and the improvement coil are connected in series and then connected to a short pulse-width power supply system.

[0017] Preferably, the current direction of the eddy current coil is opposite to that of the background magnetic field coil, and the current direction of the eddy current coil is the same as that of the improvement coil.

[0018] Preferably, a fiberglass layer is provided on the outer sides of the background magnetic field coil, the eddy current coil and the improvement coil.

[0019] The present invention provides an electromagnetic forming method and device based on a three-coil dual-power supply plate, having the following beneficial effects:

[0020] 1. The present invention realizes a new scheme for forming a plate through the cooperation of three groups of coils under the action of attractive electromagnetic force. By controlling the discharge voltage and capacitor capacitance value in the three groups of power supply devices, the eddy current and magnetic field can be flexibly regulated, and diversified loading of the Lorentz force can be achieved.

[0021] 2. The present invention realizes the effective compensation of the background magnetic field and induced eddy current weakened due to magnetic field competition and eddy current competition by introducing a group of improvement coils.

[0022] 3. The method proposed by the present invention can not only improve the overall energy utilization rate of the system, improve the processing efficiency of workpieces, but also improve the forming quality of workpieces.

[0023] 4. The mixed loading force formed by the common discharge of the three groups of coils in the present invention has a significantly better forming effect on the plate than the forming influence of a single repulsive force and attractive force on the plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the drawings and embodiments:

[0025] Figure 1 is a schematic structural diagram of the present invention;

[0026] Figure 2 is a schematic diagram of the pulse circuit of the present invention;

[0027] Figure 3 is a schematic structural diagram of the device of the present invention;

[0028] Figure 4 is a waveform diagram of the pulse current loaded on the three groups of coils of the present invention;

[0029] Figure 5 is a decoupled electromagnetic environment diagram of the three coils of the present invention;

[0030] Figure 6 is a forming diagram of the three-coil hybrid force of the present invention;

[0031] Figure 7 It is a forming diagram of the attraction of a double coil in the prior art. Specific embodiments

[0032] The present invention provides a method and device for electromagnetic forming of a plate based on three coils and two power supplies. By using three sets of coils, a background magnetic field is generated by passing a long pulse-width current through the background magnetic field coil. When the long pulse-width current reaches its peak value, short pulse-width currents are simultaneously passed through the eddy current coil and the improvement coil to cause an induced eddy current in the plate, so that the plate is formed under the action of electromagnetic force in the magnetic field.

[0033] In the present invention, the electromagnetic forming of the plate is taken as an example for analysis and verified through theory and simulation. The present invention also provides a device for implementing the above method, mainly including three sets of forming coils. The three sets of coils are coaxially placed. The background magnetic field coil and the eddy current induction coil are sequentially placed above the plate, and the improvement coil is located below the plate. First, a long pulse-width pulsed current is passed through the set of coils at the uppermost position (background magnetic field coil) to generate a background magnetic field. When the long pulse-width pulsed current reaches its peak value, short pulse-width pulsed currents are passed through the other two sets of coils, so that the plate in the magnetic field is subjected to the action of the Lorentz force. Since the directions of the pulsed currents passed through twice are opposite, the background magnetic field generated by the eddy current coil will weaken the background magnetic field generated by the background magnetic field coil. Similarly, the eddy current generated by the background magnetic field coil in the plate will also weaken the eddy current generated by the eddy current coil in the plate, that is, magnetic field competition and eddy current competition. The addition of the improvement coil greatly alleviates the two competition problems and gives great compensation to both the background magnetic field and the induced eddy current. The present invention realizes another scheme for attracting electromagnetic forming of the plate, which can meet various processing requirements and enrich the processing methods of metal alloy plates.

[0034] As Figures 1-3 shown, an electromagnetic forming method based on a three-coil and two-power-supply plate includes the following steps:

[0035] S1. Clamp the edge of the metal plate 4 to fix the metal plate. Place the background magnetic field coil 1 and the eddy current coil 2 above the metal plate, and place the improvement coil 3 below the metal plate 4;

[0036] S2. Connect the background magnetic field coil 1 to a long pulse-width power supply system to generate a background magnetic field;

[0037] S3. When the long pulse-width pulsed current reaches its peak value, connect the eddy current coil 2 and the improvement coil 3 in series and then connect them to a short pulse-width power supply system, so that the plate in the magnetic field is subjected to an upward Lorentz force and deforms upward.

[0038] Preferably, the current directions of the eddy current coil 2 and the background magnetic field coil 1 are opposite, and the current directions of the eddy current coil 2 and the improvement coil 3 are the same.

[0039] Preferably, it further includes:

[0040] S4. Conduct a comparison of the forming effect. If the forming standard is not met, return to S2; otherwise, end.

[0041] Preferably, in S1, the pressure for clamping the metal plate 4 is set to 1 to 1.5 MPa.

[0042] Preferably, before step S1, the metal plate 4 is annealed.

[0043] Preferably, the eddy current coil is placed above the forming area.

[0044] An electromagnetic forming device based on a three-coil dual-power supply plate includes an upper coil skeleton 5 for arranging a background magnetic field coil 1 and an eddy current coil 2, and a lower coil skeleton 6 for arranging an improvement coil 3; an upper clamping part 7 is provided at the lower end of the upper coil skeleton 5, the lower coil skeleton 6 is arranged in a lower clamping part 8, and the upper clamping part 7 and the lower clamping part 8 are used to clamp the metal plate 4.

[0045] Preferably, the background magnetic field coil 1 is connected to a long pulse width power supply system, and the eddy current coil 2 and the improvement coil 3 are connected in series and then connected to a short pulse width power supply system. The capacitance of the long pulse width power supply system is 2880 - 3200 μF, and the capacitance of the short pulse width power supply system is 40 - 160 μF.

[0046] Preferably, the current direction of the eddy current coil 2 is opposite to that of the background magnetic field coil 1, and the current direction of the eddy current coil 2 is the same as that of the improvement coil 3.

[0047] Preferably, a fiberglass layer 9 is provided outside the background magnetic field coil 1, the eddy current coil 2 and the improvement coil 3.

[0048] By arranging the three groups of coils coaxially, the background magnetic field coil and the induction eddy current coil are sequentially placed above the plate, and the improvement coil is located below the plate. First, a long pulse width pulsed current is passed through the uppermost background magnetic field coil, and its main function is to generate the background magnetic field required in the electromagnetic forming process. As Figure 4 shown, when the long pulse width pulsed current reaches the peak value, a short pulse width pulsed current is passed through the other two groups of coils. The eddy current coil generates the induction eddy current required for forming in the plate. Under the mutual influence of the background magnetic field and the induction eddy current, and after being adjusted by the improvement coil, the plate is subjected to an attractive magnetic field force and then undergoes deformation.

[0049] According to the left - hand rule, the present invention first conducts the coil group connected to the long - pulse - width power supply device to control the coil discharge to generate a background magnetic field. When the long - pulse - width current reaches the peak value, the eddy - current coil and the improvement coil connected to the short - pulse - width power supply device are conducted, causing induced eddy currents to be generated in the plate. At this time, since multiple coils discharge simultaneously, a magnetic - field competition occurs between the original background magnetic field and the background magnetic field generated by the subsequently connected coils, and an eddy - current competition occurs between the induced eddy currents generated in the plate by the subsequently connected coils and the induced eddy currents generated in the plate by the original coils. Under the combined action of the radial component of the background magnetic field (since the electromagnetic force coupled by the axial component of the background magnetic field and the eddy currents in the plate has a very limited influence on the forming of the plate, it is ignored) and the induced eddy currents inside the plate, the metal plate is deformed under the influence of the attractive electromagnetic force. As Figure 5 shown in the electromagnetic decoupling diagram of the three - coil, the background magnetic field generated by the background - magnetic - field coil is defined as , and the induced eddy current it generates in the plate is ; the background magnetic field generated by the eddy - current coil is , and the induced eddy current it generates in the plate is ; the background magnetic field generated by the improvement coil is , and the induced eddy current it generates in the plate is . At the same time, the direction of the background magnetic field generated by the background - magnetic - field coil is defined as the positive direction of the background magnetic field, and the direction of the induced eddy current generated by the eddy - current coil is defined as the positive direction of the induced eddy current. Then, the relationship of the background - magnetic - field competition after introducing the improvement coil is ( + ), and the relationship of the eddy - current competition is (- + + ). At this time, if analyzed in terms of decoupling, the improvement coil can be regarded as a repulsive - force coil. Therefore, the three - coil system can also be regarded as an attraction / repulsion hybrid - force loading system. However, it should be noted that this hybrid - force loading system is not a simple superposition of the attractive force and the repulsive force. The actually coupled electromagnetic force is the result of the mutual promotion of the two. Its final comparison with the forming of the double - coil attraction is as Figure 6 , 7 shown.

[0050] The multi - physical - field analysis calculation formulas involved in the present invention are as follows:

[0051] ;

[0052] In the formula, and are the axial Lorentz force and the radial Lorentz force respectively; is the induced - eddy - current density on the plate, and the clockwise direction is specified as the positive direction; and are the axial magnetic - field component and the radial magnetic - field component respectively, and The direction pointing to the center is the positive direction; , and are the background magnetic field coil, the eddy current coil, and the improved coil that form the induced eddy current on the plate respectively; , and are the background magnetic field coil, the eddy current coil, and the improved coil that generate the axial magnetic field in the forming area respectively; represents time, is the moment when the long pulse-width current reaches the peak.

[0053] The present invention uses a long pulse-width current to generate the background magnetic field required for forming. The function of the short pulse-width current is mainly to cause an induced eddy current in the plate. The plate is deformed under the action of the attractive force under the combined influence of the radial component of the background magnetic field and the eddy current in the plate. The purpose of introducing the improved coil is mainly to improve the eddy current competition problem and the magnetic field competition problem caused by the long and short pulse-width currents, and to improve the energy utilization rate of the forming system.

[0054] The first group of coils is used to generate the background magnetic field, the second group of coils is used to generate the induced eddy current in the plate, and the third group of coils is used to solve the eddy current competition and magnetic field competition problems generated by the first and second groups of coils. The metal plate is deformed under the combined action of the background magnetic field and the induced eddy current under the influence of the attractive electromagnetic force, and the overall energy utilization rate of the system is improved.

[0055] The above embodiments are only the preferred technical solutions of the present invention and should not be regarded as limitations on the present invention. The protection scope of the present invention should be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, the equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. An electromagnetic forming device based on a three-coil dual-power supply plate, Characterized in that, It includes an upper coil skeleton (5) for arranging a background magnetic field coil (1) and an eddy current coil (2), and a lower coil skeleton (6) for arranging an improvement coil (3); an upper clamping portion (7) is provided at the lower end of the upper coil skeleton (5), the lower coil skeleton (6) is arranged in the lower clamping portion (8), and the upper clamping portion (7) and the lower clamping portion (8) are used to clamp a metal plate (4); The background magnetic field coil (1) is connected to a long pulse width power supply system, and the eddy current coil (2) and the improvement coil (3) are connected to a short pulse width power supply system in series.

2. The electromagnetic forming device based on a three-coil dual-power supply plate according to claim 1, Characterized in that, The current direction of the eddy current coil (2) is opposite to that of the background magnetic field coil (1), and the current direction of the eddy current coil (2) is the same as that of the improvement coil (3).

3. The electromagnetic forming device based on a three-coil dual-power supply plate according to claim 1, Characterized in that, A fiberglass layer (9) is provided outside the background magnetic field coil (1), the eddy current coil (2) and the improvement coil (3).

4. The forming method of the electromagnetic forming device based on a three-coil dual-power supply plate according to any one of claims 1-3, Characterized in that, It includes the following steps: S1. Clamp the edge of the metal plate (4) to fix the metal plate, place the background magnetic field coil (1) and the eddy current coil (2) above the metal plate, and place the improvement coil (3) below the metal plate (4); S2. Connect the background magnetic field coil (1) to a long pulse width power supply system to generate a background magnetic field; S3. When the long pulse width pulse current reaches the peak value, connect the eddy current coil (2) and the improvement coil (3) in series to a short pulse width power supply system, so that the plate in the magnetic field is subjected to an upward Lorentz force and deforms upward.

5. The electromagnetic forming method based on a three-coil dual-power supply plate according to claim 4, Characterized in that, The current direction of the eddy current coil (2) is opposite to that of the background magnetic field coil (1), and the current direction of the eddy current coil (2) is the same as that of the improvement coil (3).

6. The electromagnetic forming method based on a three-coil dual-power supply plate according to claim 4, Characterized in that, It further includes: S4. Compare the forming effects. If the forming standard is not reached, return to S2, otherwise end.

7. The electromagnetic forming method based on a three-coil dual-power supply plate according to claim 4, Characterized in that, In S1, the pressure for clamping the metal plate (4) is set to 1 to 1.5 MPa.

8. The electromagnetic forming method based on a three-coil dual-power supply plate according to claim 4, Characterized in that, Before step S1, the metal plate (4) is annealed.

9. The electromagnetic forming method based on a three-coil dual-power supply plate according to claim 4, Characterized in that, The eddy current coil (2) is placed above the forming area.

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