Ultra-thin metal sheet forming method and mold

Abstract

The present invention discloses a method and a mold for forming an ultra-thin metal sheet, comprising an upper mold and a lower mold, wherein the upper mold is provided with an upper mold cavity, and the lower mold is provided with a lower mold cavity and a lower punch chamber which are connected to each other, an upper punch chamber is also provided in the upper mold, and the upper punch chamber is connected to the upper mold cavity through a plurality of high-pressure water distribution paths, and high-pressure sealing rings are respectively provided at the joints between the upper mold and the lower mold and the plate, and the connection position of the high-pressure water distribution path and the upper mold cavity is located at the upper corner of the mold shape of the upper mold cavity, and the upper corner is located at the upper position of the upper mold cavity, and the high-pressure sealing ring is distributed in an annular structure along the periphery of the upper mold cavity and the lower mold cavity, and the position and distribution shape of the high-pressure sealing rings of the upper mold and the lower mold are the same.

Description

Technical Field

[0001] The invention relates to the field of moulds, and in particular to an ultra-thin metal sheet forming method and a mould. Background Art

[0002] Ultra-thin metals are increasingly used in multiple fields. For example, the fuel cell metal bipolar plates currently on the market are ultra-thin metal sheets, generally 0.05-0.2MM ultra-thin metal parts, and the material is usually formed by cold extrusion or stamping. Due to the cracks and internal stress caused by the stamping of metal parts by this forming method, and the uneven wall thickness of the product at the corners, stamping or extrusion will cause the product to be stretched and cracked, as well as internal stress cracking. In addition, metal stamping and extrusion molding will also leave a scratch on the surface of the product, resulting in a reduction in the strength and time of the metal parts. Due to the charging and discharging requirements of fuel cells, the battery capacity requirements are also getting higher and higher. Since high-end fuel cells have extremely high requirements for electrodes, the electrodes have a greater impact on battery performance. The electrodes produced by traditional methods will cause the service life of fuel cell metal bipolar plates to be less than 15,000 hours, and the effect is not ideal. Summary of the invention

[0003] The invention discloses an ultra-thin metal sheet forming method and a mold, which are used to solve the deficiencies of the prior art.

[0004] To solve the above problems, the technical solution of the present invention is:

[0005] A method for forming an ultra-thin metal sheet comprises the following steps:

[0006] (1) Fill the lower mold cavity of the internal high pressure molding machine with water;

[0007] (2) Place the metal blank sheet naturally on the water surface. At this time, a natural seal is formed between the metal blank sheet and the lower mold, and the water is in a pressure-free state;

[0008] (3) The upper die is pressed down until it hits the blank sheet. Under the action of the high-pressure sealing ring, the blank sheet reaches a natural sealing state with the upper die and the lower die;

[0009] (4) The upper mold cavity and the lower mold cavity are simultaneously filled with water to increase pressure, and the upper mold simultaneously applies pressure to the lower mold. When the upper mold and the lower mold reach the set pressure, the upper mold and the lower mold are locked and pressure is maintained;

[0010] (5) Then, the upper liquid filling chamber and the lower liquid filling chamber connected to the upper mold cavity and the lower mold cavity continue to pressurize each other. When the pressurized pressure of the upper mold cavity and the lower mold cavity reaches the first-level pressure, the upper mold cavity and the lower mold cavity perform the first-level pressure maintenance under the action of the pressure control device;

[0011] (6) After the first-level pressure holding is completed, the lower liquid filling chamber of the lower mold cavity continues to increase the pressure. At this time, the metal sheet is gradually compressed toward the upper mold cavity with relatively small pressure and stable pressure under the double clamping pressure of the upper mold cavity and the lower mold cavity water pressure. Under the continuous increase in pressure of the lower liquid filling chamber of the lower mold cavity, the water in the upper mold cavity overflows back to the water tank through the overflow valve connected to the upper liquid filling chamber. The set pressure value of the overflow valve is the pressure value of the first-level pressure holding. When the lower mold cavity reaches the second-level pressure, the metal sheet is completely fitted with the inner wall of the upper mold cavity under the internal expansion of the ultra-high pressure water in the lower liquid filling chamber of the lower mold cavity, forming the shape of a thin-walled product and achieving complete forming;

[0012] (7) Perform molding and pressure maintenance on the fully molded product;

[0013] (8) After the molding and pressure holding is completed, the upper and lower mold cavities are simultaneously depressurized;

[0014] (9) After the pressure relief is completed, the upper and lower molds are opened to relieve pressure and the product is taken out to complete the product molding.

[0015] The thickness of the metal blank plate is 0.05-0.2MM.

[0016] The set pressure value is 50MPa.

[0017] The primary pressure is 100MPa.

[0018] The secondary pressure is 160-180 MPa.

[0019] The time for the locking pressure holding, the primary pressure holding and the molding pressure holding is greater than 10S.

[0020] A super-thin metal sheet forming mold comprises an upper mold and a lower mold, wherein the upper mold is provided with an upper mold cavity, and the lower mold is provided with a lower mold cavity and a lower liquid filling chamber which are interconnected. An upper liquid filling chamber is also provided in the upper mold, and the upper liquid filling chamber is connected to the upper mold cavity through a plurality of high-pressure water distribution channels. High-pressure sealing rings are respectively provided at the joints between the upper mold and the lower mold and the plate.

[0021] The connection position between the high-pressure water distribution channel and the upper mold cavity is located at the upper corner of the mold inner shape of the upper mold cavity, and the upper corner is located at the upper position of the upper mold cavity.

[0022] The high pressure sealing ring is distributed in an annular structure along the periphery of the upper mold cavity and the lower mold cavity.

[0023] The positions and distribution shapes of the high pressure sealing rings of the upper die and the lower die are the same.

[0024] The beneficial effects of the present invention are as follows: compared with traditional metal stamping and extrusion molding, the characteristics of this flexible molding are better. The internal stress of the metal plate formed by water pressure flexible molding is 95% lower than that of mechanical stamping, the distortion or cracks at the corners are 95% lower, the yield rate exceeds 95%, and there are no scratches on the surface of the product. When applied to fuel cell electrodes, it has excellent performance characteristics and the cost of improving the surface finish is also low. The battery metal bipolar plate has a long service life, and the strength and time of use of metal parts are greatly improved, with good results. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of the present invention before molding;

[0026] Figure 2 It is a schematic diagram of the structure during the molding of the present invention;

[0027] Figure 3 It is a schematic diagram of the structure after molding of the present invention;

[0028] In the figure: 1-upper die, 2-lower die, 3-upper die cavity, 4-lower die cavity, 5-high pressure sealing ring, 6-high pressure water distribution channel, 7-plate material, 8-upper liquid filling chamber, 9-lower liquid filling chamber. DETAILED DESCRIPTION

[0029] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0030] See attached Figure 1-3 , a method for forming an ultra-thin metal sheet, comprising the following steps:

[0031] (1) Fill the lower mold cavity 4 of the internal high pressure molding machine with water;

[0032] (2) The metal blank sheet 7 is then placed naturally on the water surface. At this time, a natural sealing state is formed between the metal blank sheet 7 and the lower mold 2, and the water is in a pressure-free state;

[0033] (3) The upper die 1 is pressed downward until it presses the blank sheet 7. Under the action of the high-pressure sealing ring 5, the blank sheet 7 reaches a natural sealing state with the upper die 1 and the lower die 2;

[0034] (4) The upper mold cavity 3 and the lower mold cavity 4 are simultaneously filled with water and pressurized, and the upper mold 1 simultaneously applies pressure to the lower mold 2. When the upper mold 1 and the lower mold 2 reach the set pressure, the upper mold 1 and the lower mold 2 are locked and pressure maintained;

[0035] (5) Then, the upper liquid filling chamber 8 and the lower liquid filling chamber 9 connected to the upper mold cavity 3 and the lower mold cavity 4 continue to increase the pressure of each other. When the increased pressure of the upper mold cavity 3 and the lower mold cavity 4 reaches the first-level pressure, the upper mold cavity 3 and the lower mold cavity 4 perform the first-level pressure maintenance under the action of the pressure control device;

[0036] (6) After the first-level pressure holding is completed, the lower liquid filling chamber 9 of the lower mold cavity 4 continues to increase the pressure. At this time, the metal sheet is gradually compressed toward the upper mold cavity 3 where the pressure is relatively small and remains stable under the double clamping pressure of the water pressure of the upper mold cavity 3 and the lower mold cavity 4. The water in the upper mold cavity 3 is continuously pressurized by the lower liquid filling chamber 9 of the lower mold cavity 4. The overflowed water overflows back to the water tank through the overflow valve connected to the upper liquid filling chamber 8. The set pressure value of the overflow valve is the pressure value of the first-level pressure holding. When the lower mold cavity 4 reaches the second-level pressure, the metal sheet is completely fitted with the inner wall of the upper mold cavity 3 under the internal expansion of the ultra-high pressure water in the lower liquid filling chamber 9 of the lower mold cavity 4, forming the shape of a thin-walled product and achieving complete forming;

[0037] (7) Perform molding and pressure maintenance on the fully molded product;

[0038] (8) After the molding and pressure holding is completed, the upper mold cavity 3 and the lower mold cavity 4 are simultaneously depressurized;

[0039] (9) After the pressure relief is completed, the upper mold 1 and the lower mold 2 are opened to relieve the pressure, and the product is taken out to complete the product molding.

[0040] The thickness of the metal blank plate is 0.05-0.2MM.

[0041] The set pressure value is 50MPa.

[0042] The primary pressure is 100MPa.

[0043] The secondary pressure is 160-180 MPa.

[0044] The time for the locking pressure holding, the primary pressure holding and the molding pressure holding is greater than 10S.

[0045] A super-thin metal sheet forming mold comprises an upper mold 1 and a lower mold 2, wherein the upper mold 1 is provided with an upper mold cavity 3, and the lower mold 2 is provided with a lower mold cavity 4 and a lower liquid filling chamber 9 which are connected to each other, an upper liquid filling chamber 8 is also provided in the upper mold 1, and the upper liquid filling chamber 8 is connected to the upper mold cavity 3 through a plurality of high-pressure water distribution channels 6, and high-pressure sealing rings 5 ​​are respectively provided at the joints between the upper mold 1 and the lower mold 2 and the plate 7.

[0046] The connection position between the high-pressure water distribution channel 6 and the upper mold cavity 3 is located at the upper corner of the inner shape of the upper mold cavity 1 , and the upper corner is located at the upper position of the upper mold cavity 3 .

[0047] The high pressure sealing ring 5 is distributed in an annular structure along the periphery of the upper mold cavity 3 and the lower mold cavity 4 .

[0048] The positions and distribution shapes of the high pressure sealing rings 5 ​​of the upper die 1 and the lower die 2 are the same.

[0049] In practical applications, the forming method and mold of the present invention are used in products of ultra-thin metal sheets. Compared with traditional metal stamping and extrusion molding, the characteristics of this flexible forming are better. The metal plate formed by water pressure flexible forming has an internal stress 95% lower than that of mechanical stamping, and the distortion or cracks at the corners are 95% lower. The yield rate exceeds 95%, and there are no scratches on the surface of the product. When applied to fuel cell electrodes, it has excellent performance characteristics and the cost of improving the surface finish is also low. The battery metal bipolar plate has a long service life, and the strength and time of metal parts are greatly improved. The effect is good. The upper mold cavity 3 and the lower mold cavity 4 are respectively water-injected and molded twice under primary pressure and secondary pressure to reduce the internal stress of the product and make the product more evenly stressed. At the same time, the thickness of the turning angle of the molding method is slightly different from the thickness of other parts of the product, and the product thickness is very uniform. Especially for fuel cell electrode products, there are extremely high requirements on the thickness of the product to achieve uniform charging and discharging, and due to the surface drawing marks, there will be no local discharge during charging and discharging, and the process requirements for improving the smoothness of the product in the later stage are low, and it will not affect the material thickness itself.

[0050] The above specific implementation modes are preferred embodiments of the present invention and cannot be used to limit the present invention. Any other changes or other equivalent replacement methods that do not deviate from the technical solution of the present invention are included in the protection scope of the present invention.

Claims

1. A method for forming an ultra-thin metal sheet, Features The following steps are involved: (1) Fill the lower mold cavity of the internal high pressure molding machine with water; (2) Place the metal blank sheet naturally on the water surface. At this time, a natural seal is formed between the metal blank sheet and the lower mold, and the water is in a pressure-free state; (3) The upper die is pressed down until it hits the blank sheet. Under the action of the high-pressure sealing ring, the blank sheet reaches a natural sealing state with the upper die and the lower die; (4) The upper mold cavity and the lower mold cavity are simultaneously filled with water to increase pressure, and the upper mold simultaneously applies pressure to the lower mold. When the upper mold and the lower mold reach the set pressure, the upper mold and the lower mold are locked and pressure is maintained; (5) Then, the upper liquid filling chamber and the lower liquid filling chamber connected to the upper mold cavity and the lower mold cavity continue to pressurize each other. When the pressurized pressure of the upper mold cavity and the lower mold cavity reaches the first-level pressure, the upper mold cavity and the lower mold cavity perform the first-level pressure maintenance under the action of the pressure control device; (6) After the first-level pressure holding is completed, the lower liquid filling chamber of the lower mold cavity continues to increase the pressure. At this time, the metal sheet is gradually compressed toward the upper mold cavity with relatively small pressure and stable pressure under the double clamping pressure of the upper mold cavity and the lower mold cavity water pressure. Under the continuous increase in pressure of the lower liquid filling chamber of the lower mold cavity, the water in the upper mold cavity overflows back to the water tank through the overflow valve connected to the upper liquid filling chamber. The set pressure value of the overflow valve is the pressure value of the first-level pressure holding. When the lower mold cavity reaches the second-level pressure, the metal sheet is completely fitted with the inner wall of the upper mold cavity under the internal expansion of the ultra-high pressure water in the lower liquid filling chamber of the lower mold cavity, forming the shape of a thin-walled product and achieving complete forming; (7) Perform molding and pressure maintenance on the fully molded product; (8) After the molding and pressure holding is completed, the upper and lower mold cavities are simultaneously depressurized; (9) After the pressure relief is completed, the upper and lower molds are opened to relieve pressure and the product is taken out to complete the product molding.

2. The ultra-thin metal sheet forming method according to claim 1, Features: The thickness of the metal blank plate is 0.05-0.2MM.

3. The ultra-thin metal sheet forming method according to claim 1, Features: The set pressure is 50 MPa.

4. The method for forming an ultra-thin metal sheet according to claim 1, Features: The pressure of the first-level pressure is 100MPa.

5. The method for forming an ultra-thin metal sheet according to claim 1, Features: The secondary pressure is 160-180 MPa.

6. The method for forming an ultra-thin metal sheet according to claim 1, Features: The time of the primary pressure holding and the molding pressure holding is greater than 10S.

7. An ultra-thin metal sheet forming die, used in the ultra-thin metal sheet forming method according to claim 1, Features: It includes an upper mold and a lower mold, the upper mold is provided with an upper mold cavity, the lower mold is provided with a lower mold cavity and a lower punch chamber which are connected to each other, an upper punch chamber is also provided in the upper mold, the upper punch chamber is connected with the upper mold cavity through a plurality of high-pressure water distribution channels, high-pressure sealing rings are respectively provided at the joints between the upper mold and the lower mold and the plate, the connection position of the high-pressure water distribution channel and the upper mold cavity is located at the upper corner of the inner shape of the upper mold cavity, and the upper corner is located at the upper position of the upper mold cavity.

8. The ultra-thin metal sheet forming die according to claim 7, Features: The high pressure sealing ring is distributed in an annular structure along the periphery of the upper mold cavity and the lower mold cavity.

9. The ultra-thin metal sheet forming die according to claim 7, Features: The positions and distribution shapes of the high pressure sealing rings of the upper die and the lower die are the same.

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