Forming production process suitable for metal sheet

Abstract

The invention discloses a forming production process suitable for a metal sheet, which comprises the following steps of: 1, mounting a driving coil formed by winding a copper wire on an upper die fixing plate of a die, and manufacturing a cavity by a lower die plate according to the shape of a target forming workpiece; secondly, the upper die and the lower die are close to each other, meanwhile, a pressing mechanism composed of a buffer pad and a blank holder is made to make contact with the formed workpiece, needed contact force is kept, and then the die is closed so that the drive coil can be placed at the position close to the formed workpiece; the electromagnetic forming technology is used for replacing a traditional forming mode, the development cost of battery pack cover plates, trays and protection plate parts is effectively reduced, and the production benefit is improved; in the production and machining process, the production process is easy to control and high in repeatability, and only a single-side mold needs to be used, so that the tool cost is saved; in addition, friction between the thin plate and the die is reduced, use of lubricating oil can be reduced or avoided, and the working environment is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic forming, in particular to a forming production process suitable for metal thin plates. Background Art

[0002] As we all know, new energy vehicles refer to vehicles that use unconventional automotive fuels as their power source and integrate advanced technologies in vehicle power control and drive to form vehicles with advanced technical principles, new technologies and new structures; new energy vehicles include pure electric vehicles, extended-range electric vehicles, hybrid vehicles, fuel cell electric vehicles, hydrogen engine vehicles, etc.

[0003] The power battery pack is one of the core components of new energy vehicles. Its function is to bear the weight of the battery and, under special circumstances, it plays a key role in the safe operation and protection of the battery module. The overall requirements for the strength, rigidity, and processability of the battery tray are relatively high. Among them, the battery pack cover, tray, and guard plate parts bear the main structural strength and anti-intrusion protection functions, protecting the vehicle and passengers from damage caused by thermal runaway, fire, smoke, and electromagnetic fields, and also isolating pollutants such as dust, debris, and moisture. In addition, the battery pack cover, tray, and guard plate parts are all large in size and thin in thickness. In order to improve the structural and anti-intrusion strength, the traditional sheet metal cold stamping process is more difficult to form when faced with the production of high-strength or even ultra-rigid strength cold-formed steel. There are problems such as low material ductility, high forming clamping force, rapid mold consumption, obvious surface indentation of parts, and large dimensional deformation.

[0004] In recent years, the market has introduced a process for hot-formed steel guard plates. This process, which involves heating the hot-formed steel sheet and then quenching it in a mold, solves the problems of cold-stamped sheet metal, such as high strength, difficulty in forming, low elongation, and high springback. It also significantly improves the material strength of the finished parts, achieving tensile strengths of 1500MPa or even 2000MPa, while also providing greater resistance to external forces. However, hot-formed guard plates still have drawbacks: the complex and costly mold structure leads to high production equipment investment costs, resulting in higher unit prices for parts. To address this, we propose a forming production process suitable for thin metal sheets.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0006] The object of the present invention is to provide a forming production process suitable for metal sheets to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a forming production process suitable for metal sheets, comprising the following steps:

[0008] Step 1: Install the drive coil made of copper wire on the upper mold fixing plate of the mold, and make the cavity of the lower mold plate according to the shape of the target workpiece;

[0009] Step 2: The upper die and the lower die are brought closer to each other, and the pressing mechanism composed of the buffer pad and the blank holder is brought into contact with the formed workpiece while maintaining the required contact force. The mold is then closed so that the driving coil is placed close to the formed workpiece.

[0010] Step 3: Under the control of the high-voltage system circuit structure, the current in the drive coil connected to the two electrodes changes suddenly, thereby exciting and generating a pulsed strong magnetic field around the drive coil;

[0011] Step 4: Since the workpiece is very close to the energized drive coil, the workpiece is in a strong pulsed magnetic field. The magnetic field generated by the energized drive coil changes, and an induced current begins to be generated inside the workpiece.

[0012] Step 5: The induced current inside the formed workpiece generates an induced magnetic field that repels the coil magnetic field. The repulsive magnetic field force and the electromagnetic force act on the formed workpiece, and the formed workpiece locally obtains huge kinetic energy in a very short time, causing the formed workpiece to quickly approach the specific shape cavity of the impact template, thereby causing plastic deformation;

[0013] Step 6: After the forming is completed, the current in the driving coil is released to eliminate the electromagnetic force;

[0014] Step 7: Move the upper die and the lower die away from each other and remove the formed workpiece from the die.

[0015] Preferably, in steps three to five, the main principle of electromagnetic forming is that the high-voltage power supply system charges the capacitor, disconnects the charging switch after charging is completed, and instantly closes the discharge circuit switch. The energy storage system will instantly release electrical energy to the discharge circuit, and a high-frequency and high-intensity pulse current will be generated in the working coil in the discharge circuit. According to Faraday's law of electromagnetic induction, at this time, the metal blank will move at a high speed away from the coil under the action of the strong magnetic field force given by the induced magnetic field and undergo plastic forming.

[0016] Preferably, in steps three to five, the essence of electromagnetic forming is a production application of Lenz's law and Faraday's law of electromagnetic induction, which mainly utilizes the high-speed movement of a current-carrying conductor under the action of the Lorentz force in a magnetic field for forming. In addition, the electromagnetic forming system is mainly composed of a high-voltage power supply system, an energy storage system, a discharge circuit and a control system.

[0017] Preferably, the magnetic field force is the Lorentz force, which is specifically the force exerted on the moving charges in the magnetic field, that is, the force exerted by the magnetic field on the moving charges.

[0018] Preferably, in step five, the instantaneous speed of electromagnetic forming of the sheet material can reach above 100 meters per second.

[0019] Preferably, the entire forming process of the sheet material is completed within 1 millisecond.

[0020] Preferably, the typical sheet metal part after forming has a thickness of 1.0 mm, is made of HC820 / 1180DP, and has a shallow molding depth.

[0021] Preferably, the typical metal sheet part has a relatively small fillet, with the minimum fillet being R2 mm.

[0022] In summary, this application includes at least one of the following beneficial technical effects:

[0023] The present invention uses electromagnetic forming technology instead of traditional forming methods, which effectively reduces the development cost of battery pack cover, tray, and guard plate parts and improves production efficiency; and electromagnetic forming of metal sheets increases the forming limit of the material, which is particularly suitable for the forming of high-strength and ultra-high-strength materials. It also has the function of reducing rebound and suppressing wrinkling. In addition, non-contact forming can make the surface quality of the formed parts good, and can directly process metals with surface coatings without damaging the protective film layer; during the production and processing process, this production process is easy to control and has high repeatability, and only needs to use a single-sided mold, thereby saving tooling costs; in addition, the friction between the thin plate and the mold is reduced, which can reduce or avoid the use of lubricating oil, thereby improving the working environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the principle of generating induced magnetic field force in the forming production process applicable to metal sheets;

[0025] Figure 2 Schematic diagram of the electromagnetic forming principle of a sheet metal in the forming production process of the present invention;

[0026] Figure 3 Schematic diagram of a typical metal sheet part in the forming production process of the metal sheet according to the present invention.

[0027] In the figure: 1. Driving coil and current; 2. Strong magnetic field; 3. Induced current; 4. Induced magnetic field; 5. Magnetic field force; 6. Metal conductor blank; 7. Upper die fixing plate; 8. Buffer pad; 9. Blank holder; 10. Lower die plate; 11. Formed workpiece; 12. Driving coil; 13. Electromagnetic force; 14. High-voltage system circuit structure; 15. Typical metal sheet parts. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] See also Figure 1-Figure 3 The present invention provides a technical solution: a forming production process suitable for metal sheets, characterized in that it includes the following steps:

[0030] Step 1: Install the drive coil 12 made of copper wire on the upper mold fixing plate 7 of the mold, and make the cavity of the lower mold plate 10 according to the shape of the target workpiece;

[0031] Step 2: The upper mold and the lower mold are brought closer to each other, and the pressing mechanism composed of the buffer pad 8 and the blank holder 9 is brought into contact with the formed workpiece 11 while maintaining the required contact force. The mold is then closed so that the driving coil 12 is placed close to the formed workpiece 11.

[0032] Step 3: Under the control of the high-voltage system circuit structure 14, the current in the driving coil 12 connected to the two electrodes changes suddenly, thereby exciting and generating a pulsed strong magnetic field 2 around the driving coil 12;

[0033] Step 4: Since the formed workpiece 11 is very close to the energized driving coil 12, the formed workpiece 11 is in the pulsed strong magnetic field 2. The magnetic field generated by the energized driving coil 12 changes, and an induced current 3 begins to be generated inside the formed workpiece 11.

[0034] Step 5: The induced current inside the formed workpiece 11 generates an induced magnetic field 4 that repels the coil magnetic field. The repulsive magnetic field force 5 and the electromagnetic force 13 act on the formed workpiece 11. The formed workpiece 11 locally obtains huge kinetic energy in a very short time, causing the formed workpiece 11 to quickly approach and impact the specific shape of the cavity of the lower template 10, thereby causing plastic deformation;

[0035] Step 6: After the forming is completed, the current in the driving coil 12 is released to eliminate the electromagnetic force;

[0036] Step 7: Move the upper die and the lower die away from each other and remove the formed workpiece 11 from the die.

[0037] In one embodiment, the main principle of electromagnetic forming is that the high-voltage power supply system charges the capacitor, disconnects the charging switch after charging is completed, and instantly closes the discharge circuit switch. The energy storage system will instantly release electrical energy to the discharge circuit, and a high-frequency and high-intensity pulse current 1 will be generated in the working coil in the discharge circuit. According to Faraday's law of electromagnetic induction, at this time, the metal blank 6 will move at high speed away from the coil under the action of the strong magnetic field force 5 given by the induced magnetic field 4 and undergo plastic forming; the essence of electromagnetic forming is a production application of Lenz's law and Faraday's law of electromagnetic induction. It mainly uses the current-carrying conductor to be subjected to the Lorentz force in the magnetic field and move at high speed for forming. In addition, the electromagnetic forming system is mainly composed of a high-voltage power supply system, an energy storage system, a discharge circuit and a control system.

[0038] In one embodiment, the magnetic field force 5 is the Lorentz force. The Lorentz force is specifically the force exerted on the moving charge in the magnetic field, that is, the force exerted by the magnetic field on the moving charge.

[0039] In one embodiment, the instantaneous speed of electromagnetic forming of the sheet material can reach over 100 meters per second, and the entire forming process of the sheet material is completed within 1 millisecond.

[0040] In one embodiment, the typical sheet metal part 15 after forming has a thickness of 1.0 mm and is made of HC820 / 1180DP. The part has a shallow molding depth and a small fillet, with a minimum fillet of R2 mm.

[0041] In summary: The present invention uses electromagnetic forming technology instead of traditional forming methods, which effectively reduces the development cost of battery pack cover plates, trays, and guard plate parts, and improves production efficiency; and electromagnetic forming of metal sheets increases the forming limit of the material, which is particularly suitable for the forming of high-strength and ultra-high-strength materials. It also has the function of reducing rebound and suppressing wrinkling. In addition, non-contact forming can make the surface quality of the formed parts good, and can directly process metals with surface coatings without damaging the protective film layer; during the production and processing process, this production process is easy to control and has high repeatability, and only needs to use a single-sided mold, thereby saving tooling costs; in addition, the friction between the thin plate and the mold is reduced, which can reduce or avoid the use of lubricating oil, thereby improving the working environment.

[0042] Parts not described in the present invention are the same as those in the prior art or can be implemented using the prior art. Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A forming production process suitable for metal sheets, characterized in that: The following steps are involved: Step 1: First, a driving coil (12) made of copper wire is installed on the upper mold fixing plate (7) of the mold, and the lower mold plate (10) is made into a mold cavity according to the shape of the target formed workpiece; Step 2: The upper mold and the lower mold are brought closer to each other, and the pressing mechanism composed of the buffer pad (8) and the pressure ring (9) is brought into contact with the formed workpiece (11) while maintaining the required contact force, and then the mold is closed so that the driving coil (12) is placed in a position close to the formed workpiece (11); Step 3: Under the control of the high-voltage system circuit structure (14), the current in the driving coil (12) connected to the two electrodes changes suddenly, thereby exciting and generating a pulsed strong magnetic field (2) around the driving coil (12); Step 4: Since the formed workpiece (11) is very close to the energized driving coil (12), the formed workpiece (11) is in a pulsed strong magnetic field (2), and the magnetic field generated by the energized driving coil (12) changes, so an induced current (3) begins to be generated inside the formed workpiece (11); Step 5: The induced current inside the formed workpiece (11) generates an induced magnetic field (4) that repels the coil magnetic field. The repulsive magnetic field force (5) and the electromagnetic force (13) act on the formed workpiece (11). The formed workpiece (11) locally obtains huge kinetic energy in a very short time, causing the formed workpiece (11) to quickly approach and impact the specific shape cavity of the lower template (10), thereby causing plastic deformation. Step 6: After the forming is completed, the current in the driving coil (12) is released to eliminate the electromagnetic force; Step 7: Move the upper die and the lower die away from each other and remove the formed workpiece (11) from the die.

2. The forming production process for metal sheets according to claim 1, characterized in that: In steps 3 to 5, the main principle of electromagnetic forming is that the high-voltage power supply system charges the capacitor, disconnects the charging switch after charging is completed, and instantly closes the discharge circuit switch. The energy storage system will instantly release electrical energy to the discharge circuit, and a high-frequency and high-intensity pulse current (1) will be generated in the working coil in the discharge circuit. According to Faraday's law of electromagnetic induction, at this time, the metal blank (6) will move at high speed away from the coil under the action of the strong magnetic field force (5) given by the induced magnetic field (4) to undergo plastic forming.

3. The forming production process for metal sheets according to claim 1, characterized in that: In steps three to five, the essence of electromagnetic forming is a production application of Lenz's law and Faraday's law of electromagnetic induction. It mainly uses the high-speed movement of current-carrying conductors under the action of Lorentz force in a magnetic field to perform forming. In addition, the electromagnetic forming system is mainly composed of a high-voltage power supply system, an energy storage system, a discharge circuit and a control system.

4. The forming production process for metal sheets according to claim 2, characterized in that: The magnetic field force (5) is the Lorentz force, which is specifically the force exerted on a moving charge in a magnetic field, that is, the force exerted by the magnetic field on the moving charge.

5. The forming production process for metal sheets according to claim 1, characterized in that: In step five, the instantaneous speed of electromagnetic forming of the sheet material can reach over 100 meters per second.

6. The forming production process for metal sheets according to claim 1, characterized in that: The entire forming process of the sheet is completed within 1 millisecond.

7. The forming production process for metal sheets according to claim 1, characterized in that: The typical sheet metal part (15) after forming has a thickness of 1.0 mm and is made of HC820 / 1180DP.

8. The forming production process for metal sheets according to claim 7, characterized in that: The minimum fillet of the typical metal sheet part (15) is R2 mm.

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