Method for pressing copper sheet inductors and pressing die

Abstract

The application belongs to the technical field of inductance preparation, and discloses a copper sheet inductance pressing method and a pressing die. The copper sheet inductance pressing method is characterized by the following steps: firstly, pre-pressing the powder on one side of the copper sheet; then, putting the copper sheet into the pre-pressed powder; thirdly, injecting the powder into the other side of the copper sheet; and finally, simultaneously performing forming pressing on both sides of the copper sheet. The segmented filling and segmented pressing process is used to avoid the problem that the powder content on both sides of the copper sheet is different when the powder is injected due to the blockage of the copper sheet in the one-step forming pressing process, so that the copper sheet inductance with uniform density is obtained by the copper sheet inductance pressing method. The copper sheet inductance meets the performance requirements, and the formed copper sheet inductance is not prone to cracking, deformation and other adverse problems, and the product quality is excellent.

Description

Technical Field

[0001] This invention relates to the field of inductor fabrication technology, and in particular to a method for pressing copper sheet inductors and a pressing mold. Background Technology

[0002] When copper sheet inductors are pressed, the copper sheet placed in the pressing mold cavity divides the cavity into upper and lower chambers. This causes the powder content in the upper and lower parts of the copper sheet to differ due to the obstruction of the copper sheet during powder filling. As a result, after pressing, the upper and lower sides of the copper sheet inductor have a certain density difference. This not only fails to meet the performance requirements, but also makes the formed copper sheet inductor prone to cracking, deformation and other defects. Summary of the Invention

[0003] The purpose of this invention is to provide a method and mold for pressing copper sheet inductors. After pressing, the copper sheet inductor has uniform density on both sides, meets the performance standards, and is less prone to cracking, deformation and other defects, resulting in excellent product quality.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] On the one hand, a method for pressing copper sheet inductors is provided, the method comprising the following steps:

[0006] S1. Install the pressing mold into the pressure equipment. The pressing mold includes an upper mold, a lower mold, an upper die, and a lower die. The upper die has an upper punch on the side facing the lower die. The lower die has a lower cavity on the side facing the upper die. The lower die has a first channel communicating with the lower cavity. The upper die has a second channel corresponding to the first channel.

[0007] S2. Insert the lower die into the first channel and close the upper die and the lower die to make the upper punch and the lower die cavity close together to form a molding cavity;

[0008] S3. Inject a set amount of powder into the molding cavity through the second channel;

[0009] S4. Insert the upper mold into the second channel, and the pressure device simultaneously drives the upper mold and the lower mold to move closer to each other to pre-press the powder in the forming cavity to obtain a sheet product.

[0010] S5. After pressing is completed, separate the upper die and the lower die, put the copper sheet into the lower die cavity, at which time the copper sheet is located above the sheet product, and close the upper die and the lower die again.

[0011] S6. A set amount of powder is injected into the molding cavity through the second channel, at which time the powder accumulates in the second channel above the copper sheet;

[0012] S7. Insert the upper die into the second channel. The pressure device simultaneously drives the upper die and the lower die to move closer to each other and apply pressure to the upper and lower sides of the copper sheet. The lower die shapes and presses the sheet product below the copper sheet, and the upper die shapes and presses the powder above the copper sheet to obtain copper sheet inductance.

[0013] S8. After pressing is completed, the upper die and the lower die are separated. The pressure device drives the lower die to rise towards the upper die so that the copper inductor can be removed from the lower die cavity. The worker collects the removed copper inductor to complete the pressing operation.

[0014] Optionally, in step S3, the amount of powder injected should be such that after the pre-pressing as in step S4, the formed sheet product is flush with the bottom surface of the lower mold cavity.

[0015] Optionally, the thickness of the copper sheet is set to T. In step S5, when the upper die and the lower die are closed again, the gap between the upper punch and the bottom surface of the lower die cavity is W, and satisfies W = T + 0.03 mm.

[0016] Optionally, in step S4, the pressure during pre-compression is F1, and satisfies 0.95T≤F1≤1.05T.

[0017] Optionally, in step S4, the holding time during pre-compression is t1, and satisfies 0.1s≤t1≤0.3s.

[0018] Optionally, in step S7, the pressure during molding and pressing is F2, and satisfies 18.5T≤F2≤19.5T.

[0019] Optionally, in step S4, the holding time during molding and pressing is t2, and satisfies 0.1s≤t2≤0.3s.

[0020] On the other hand, a pressing die is provided, wherein the pressing die is used to perform the pressing operation by the copper sheet inductor pressing method as described in any of the preceding claims, and the pressing die includes the upper pressing die, the lower pressing die, the upper concave die, and the lower concave die.

[0021] Optionally, the pressing mold further includes a guide member, which is inserted into the upper cavity and extends out of the upper cavity toward the surface of the lower cavity, and the lower cavity has a guide channel corresponding to the guide member.

[0022] Optionally, the second channel includes a first hole segment and a second hole segment. The first hole segment is located on the side of the upper die away from the lower die, and the second hole segment is located on the side of the upper die close to the lower die. The first hole segment is a trumpet shape with a diameter that gradually decreases as it approaches the second hole segment.

[0023] The beneficial effects of this invention are:

[0024] This invention provides a method for pressing copper sheet inductors. When pressing the copper sheet inductor, powder is first pre-pressed on one side of the copper sheet, then the copper sheet is placed in, and powder is injected onto the other side of the copper sheet. Finally, both sides of the copper sheet are simultaneously pressed and shaped. By utilizing segmented filling and segmented pressing processes, the problem of uneven powder content on both sides of the copper sheet during powder injection, caused by the copper sheet obstructing the process in a single pressing step, is avoided. This results in a copper sheet inductor with uniform density, ensuring that performance requirements are met and that the formed copper sheet inductor is less prone to cracking, deformation, and other defects, resulting in excellent product quality.

[0025] The present invention also provides a pressing mold, which, by applying the above-mentioned copper sheet inductive pressing method, ensures that the pressing mold is subjected to uniform force during pressing, is not easily damaged, and thus extends the service life of the pressing mold. Attached Figure Description

[0026] Figure 1 This is a flowchart of the copper sheet inductor pressing method provided by the present invention;

[0027] Figure 2 This is an exploded view of the pressing mold provided by the present invention;

[0028] Figure 3 This is a schematic diagram of the upper concave die in the pressing mold provided by the present invention;

[0029] Figure 4 This is a cross-sectional view of the upper die in the pressing mold provided by the present invention;

[0030] Figure 5 This is a schematic diagram of the lower die in the pressing mold provided by the present invention;

[0031] Figure 6 This is a cross-sectional view of the lower die in the pressing mold provided by the present invention.

[0032] In the picture:

[0033] 1. Upper mold;

[0034] 2. Lower pressing mold;

[0035] 3. Upper die; 31. Upper punch; 32. Second channel; 321. First hole section; 322. Second hole section;

[0036] 4. Lower die; 41. Lower die cavity; 42. First channel; 43. Guide channel;

[0037] 5. Guide components. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0039] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0041] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0042] When copper sheet inductors are pressed, the copper sheet placed in the pressing mold cavity divides the cavity into upper and lower chambers. This causes the powder content in the upper and lower parts of the copper sheet to differ due to the obstruction of the copper sheet during powder filling. As a result, after pressing, the upper and lower sides of the copper sheet inductor have a certain density difference. This not only fails to meet the performance requirements, but also makes the formed copper sheet inductor prone to cracking, deformation and other defects.

[0043] Therefore, in order to solve the problems of uneven inductance density, cracking, deformation and other defects in the formed copper sheet inductor, this embodiment provides a method for pressing copper sheet inductors.

[0044] like Figures 1 to 6 As shown, the copper sheet inductor pressing method includes the following steps:

[0045] S1. Install the pressing mold into the pressure equipment. The pressing mold includes an upper pressing mold 1, a lower pressing mold 2, an upper concave mold 3 and a lower concave mold 4. The upper concave mold 3 is provided with an upper punch 31 on the side facing the lower concave mold 4. The lower concave mold 4 is provided with a lower mold cavity 41 on the side facing the upper concave mold 3. A first channel 42 communicating with the lower mold cavity 41 is opened on the lower concave mold 4. A second channel 32 corresponding to the first channel 42 is opened on the upper concave mold 3.

[0046] S2. Insert the lower die 2 into the first channel 42 and close the upper die 3 and the lower die 4 to make the upper punch 31 and the lower die cavity 41 close together to form a molding cavity.

[0047] S3. Inject a set amount of powder into the molding cavity through the second channel 32;

[0048] S4. Insert the upper mold 1 into the second channel 32. The pressure device simultaneously drives the upper mold 1 and the lower mold 2 to move closer to each other, pre-pressing the powder in the forming cavity to obtain a sheet product.

[0049] S5. After pressing is completed, separate the upper die 3 and the lower die 4, put the copper sheet into the lower mold cavity 41. At this time, the copper sheet is above the sheet product, and then close the upper die 3 and the lower die 4 again.

[0050] S6. A set amount of powder is injected into the molding cavity through the second channel 32. At this time, the powder accumulates in the second channel 32 above the copper sheet.

[0051] S7. Insert the upper die 1 into the second channel 32. The pressure device simultaneously drives the upper die 1 and the lower die 2 to move closer to each other and apply pressure to the upper and lower sides of the copper sheet. The lower die 2 shapes and presses the sheet-like product below the copper sheet, and the upper die 1 shapes and presses the powder above the copper sheet to obtain copper sheet inductance.

[0052] S8. After pressing is completed, the upper die 3 and the lower die 4 are separated. The pressure equipment drives the lower die 2 to rise towards the upper die 3 so that the copper sheet inductor can be removed from the lower die cavity 41. The workers collect the removed copper sheet inductor to complete the pressing operation.

[0053] By pre-pressing powder on one side of the copper sheet during the pressing process of copper sheet inductors, then placing the copper sheet in, injecting powder onto the other side of the copper sheet, and finally simultaneously pressing both sides of the copper sheet, the segmented filling and segmented pressing process is used to avoid the problem of uneven powder content on both sides of the copper sheet during powder injection, which occurs in a single pressing process due to the obstruction of the copper sheet. This results in uneven density on both sides of the pressed copper sheet inductor. This method produces copper sheet inductors with uniform density, which not only meets performance requirements but also makes the formed copper sheet inductors less prone to cracking, deformation, and other defects, resulting in excellent product quality.

[0054] Optionally, in step S3, the amount of powder injected should be such that after the pre-pressing in step S4, the formed sheet product is flush with the bottom surface of the lower mold cavity 41. By making the formed sheet product flush with the bottom surface of the lower mold cavity 41, the shape of the sheet product is limited, and the sheet product is prevented from occupying the space of the lower mold cavity 41, thus reserving space for the subsequent insertion of copper sheets.

[0055] Optionally, the thickness of the copper sheet is set to T. In step S5, when the upper die 3 and the lower die 4 are closed again, the gap between the upper punch 31 and the bottom surface of the lower die cavity 41 is W, which satisfies W = T + 0.03 mm. By limiting the gap W between the upper punch 31 and the lower die cavity 41 to satisfy W = T + 0.03 mm, it is ensured that when the copper sheet is placed in for forming and pressing, the upper punch 31 will not damage the copper sheet, thus affecting the product performance of the copper sheet inductor after forming.

[0056] In this embodiment, the thickness of the copper sheet is 0.3mm, so it is necessary to ensure that the gap between the upper punch 31 and the bottom surface of the lower die cavity 41 is 0.33mm.

[0057] Optionally, in step S4, the pressure during pre-pressing is F1, and it satisfies 0.95T≤F1≤1.05T. By pressing the pre-pressing pressure F1 to satisfy 0.95T≤F1≤1.05T, on the one hand, it avoids the sheet product not forming due to insufficient pre-pressing pressure, and on the other hand, it avoids the sheet product having excessive density after forming due to excessive pre-pressing pressure, which would affect the density of the copper sheet inductor after forming.

[0058] Optionally, in step S4, the holding time during pre-pressing is t1, and it satisfies 0.1s≤t1≤0.3s. By limiting the holding time t1 during pre-pressing to satisfy 0.1s≤t1≤0.3s, cracking of the sheet product after pressing is avoided.

[0059] Optionally, in step S7, the pressure during molding and pressing is F2, and it satisfies 18.5T≤F2≤19.5T. By pressing the molding and pressing pressure F2 to satisfy 18.5T≤F2≤19.5T, on the one hand, it avoids the copper sheet inductor not forming due to insufficient pressure during molding and pressing; on the other hand, it avoids the copper sheet inductor's product performance being affected by excessive pressure during molding and pressing, which would result in excessive density on both sides after molding.

[0060] Optionally, in step S4, the holding time during molding and pressing is t2, and it satisfies 0.1s≤t2≤0.3s. By limiting the holding time t2 during molding and pressing to satisfy 0.1s≤t2≤0.3s, cracking of the copper sheet inductor after pressing is avoided, which would affect the product performance of the copper sheet inductor.

[0061] like Figures 2 to 6 As shown, in this embodiment, a pressing mold is also provided. The pressing mold uses the above-mentioned copper sheet inductor pressing method to perform the pressing operation. The pressing mold includes an upper pressing mold 1, a lower pressing mold 2, an upper concave mold 3, and a lower concave mold 4.

[0062] By applying the aforementioned copper sheet inductive pressing method, the pressing mold ensures that the powder density on both sides of the copper sheet is uniform during pressing, thus ensuring that the pressing mold is subjected to uniform force during pressing, making it less prone to damage and extending the service life of the pressing mold.

[0063] In this embodiment, as shown in Table 1, the influence of the density difference between the upper and lower parts of the copper sheet inductance on the life of the pressing mold and the cracking rate is verified through one embodiment and two comparative examples.

[0064] Table 1

[0065]

[0066] As can be seen from Example 1, when the density difference between the upper and lower parts is between 0.01 g / cm3 and 0.03 g / cm3, the surface of the formed copper sheet inductor does not crack, and due to the uniform force on the pressing mold, its service life is 50034 hours.

[0067] As shown in Comparative Example 1, when the density difference between the upper and lower parts is between 1.05 g / cm3 and 1.21 g / cm3, 29.8% of the products on the surface of the formed copper sheet inductor cracked, and due to the uneven stress on the pressing mold, its service life was 1982 hours.

[0068] As shown in Comparative Example 2, when the density difference between the upper and lower parts is between 0.97 g / cm3 and 1.22 g / cm3, 32.3% of the products on the surface of the formed copper sheet inductor cracked, and due to the uneven stress on the pressing mold, its service life was 2133 hours.

[0069] In summary, when the density difference between the upper and lower sections of the formed copper sheet inductor is small, the cracking rate is low, or even nonexistent. Furthermore, the uniform stress on the pressing die significantly extends its service life. Conversely, when the density difference between the upper and lower sections of the formed copper sheet inductor is large, the cracking rate is high, and the uneven stress on the pressing die significantly shortens its service life.

[0070] Optionally, such as Figure 2 , Figure 5 As shown, the pressing mold also includes a guide member 5. The guide member 5 is inserted into the upper die 3 and extends out of the upper die 3 towards the surface of the lower die 4. The lower die 4 has a guide channel 43 corresponding to the guide member 5. By providing the guide member 5 on the upper die 3 and the guide channel 43 on the lower die 4, the guide member 5 is inserted into the guide channel 43 when the upper die 3 and the lower die 4 are closed, thereby limiting and guiding the closing of the upper die 3 and the lower die 4, thus ensuring the accuracy of the position of the upper die 3 and the lower die 4 when they are closed.

[0071] Optionally, such as Figure 4 As shown, the second channel 32 includes a first section 321 and a second section 322. The first section 321 is located on the side of the upper die 3 away from the lower die 4, and the second section 322 is located on the side of the upper die 3 closer to the lower die 4. The first section 321 is a funnel shape with its diameter gradually decreasing towards the second section 322. By making the second section 322 of the second channel 32 a funnel shape with a larger upper section and a smaller lower section, the upper die 1 can be inserted into the second channel 32 more smoothly. Furthermore, since the diameter of the second section 322 gradually decreases, it can also guide the sliding of the upper die 1 within the second channel 32.

[0072] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for pressing copper sheet inductors, characterized in that, The copper sheet inductor pressing method includes the following steps: S1. Install the pressing mold into the pressure equipment. The pressing mold includes an upper pressing mold (1), a lower pressing mold (2), an upper concave mold (3), and a lower concave mold (4). The upper concave mold (3) has an upper punch (31) on the side facing the lower concave mold (4). The lower concave mold (4) has a lower mold cavity (41) on the side facing the upper concave mold (3). The lower concave mold (4) has a first channel (42) communicating with the lower mold cavity (41). The upper concave mold (3) has a second channel (32) corresponding to the first channel (42). S2. Insert the lower die (2) into the first channel (42) and close the upper die (3) and the lower die (4) to make the upper punch (31) and the lower die cavity (41) close into a forming die cavity; S3. Inject a set amount of powder into the molding cavity through the second channel (32); S4. Insert the upper mold (1) into the second channel (32), and the pressure device simultaneously drives the upper mold (1) and the lower mold (2) to move closer to each other to pre-press the powder in the molding cavity to obtain a sheet product. S5. After pressing is completed, separate the upper concave mold (3) and the lower concave mold (4), put the copper sheet into the lower mold cavity (41), at this time the copper sheet is above the sheet product, and close the upper concave mold (3) and the lower concave mold (4) again. S6. A set amount of powder is injected into the molding cavity through the second channel (32), at which time the powder accumulates in the second channel (32) above the copper sheet; S7. Insert the upper die (1) into the second channel (32). The pressure device simultaneously drives the upper die (1) and the lower die (2) to move closer to each other and apply pressure to the upper and lower sides of the copper sheet. The lower die (2) shapes and presses the sheet product below the copper sheet, and the upper die (1) shapes and presses the powder above the copper sheet to obtain copper sheet inductance. S8. After pressing is completed, the upper die (3) and the lower die (4) are separated. The pressure device drives the lower die (2) to rise towards the upper die (3) so that the copper sheet inductor can be removed from the lower die cavity (41). The worker collects the removed copper sheet inductor to complete the pressing operation.

2. The copper sheet inductor pressing method according to claim 1, characterized in that, In step S3, the amount of powder injected should be such that after the pre-pressing in step S4 is completed, the formed sheet product is flush with the bottom surface of the lower mold cavity (41).

3. The method for pressing copper sheet inductors according to claim 1, characterized in that, The thickness of the copper sheet is set to T. In step S5, when the upper die (3) and the lower die (4) are closed again, the gap between the upper punch (31) and the bottom surface of the lower die cavity (41) is W, and satisfies that W = T + 0.03 mm.

4. The copper sheet inductor pressing method according to claim 1, characterized in that, In step S4, the pressure during pre-compression is F1, and it satisfies 0.95T≤F1≤1.05T.

5. The method for pressing copper sheet inductors according to claim 1, characterized in that, In step S4, the holding time during pre-compression is t1, and it satisfies 0.1s≤t1≤0.3s.

6. The method for pressing copper sheet inductors according to claim 1, characterized in that, In step S7, the pressure during molding and pressing is F2, and it satisfies 18.5T≤F2≤19.5T.

7. The method for pressing copper sheet inductors according to claim 1, characterized in that, In step S4, the holding time during molding and pressing is t2, and it satisfies 0.1s≤t2≤0.3s.

8. A pressing mold, characterized in that, The pressing mold is used for pressing operations using the copper sheet inductor pressing method as described in any one of claims 1-7. The pressing mold includes the upper pressing mold (1), the lower pressing mold (2), the upper concave mold (3), and the lower concave mold (4).

9. The pressing mold according to claim 8, characterized in that, The pressing mold also includes a guide (5), which is inserted into the upper concave mold (3) and extends out of the upper concave mold (3) toward the surface of the lower concave mold (4). The lower concave mold (4) has a guide channel (43) corresponding to the guide (5).

10. The pressing mold according to claim 8, characterized in that, The second channel (32) includes a first hole segment (321) and a second hole segment (322). The first hole segment (321) is located on the side of the upper die (3) away from the lower die (4), and the second hole segment (322) is located on the side of the upper die (3) close to the lower die (4). The first hole segment (321) is a trumpet shape with a diameter that gradually decreases as it approaches the second hole segment (322).

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