A method for manufacturing a magnetic core embedded copper inductor and the inductor

Abstract

The application relates to the field of inductor manufacturing, and particularly relates to a manufacturing method of a copper-embedded magnetic core inductor and the inductor. The method first prepares a soft magnetic material and a copper conductor. Then, the soft magnetic material is pressed into a whole magnetic core preform through a cold pressing process. Then, the copper conductor is embedded into a mounting groove along the pressing direction to form an inductor preform. Finally, the inductor preform is secondarily pressed using a hot pressing process, so that the copper conductor is tightly combined with the magnetic core preform to form a final inductor body. Through the innovative design, the magnetic core preform is arranged as a whole structure, and a mounting groove matched with the copper conductor is reserved in the magnetic core preform, and then the hot pressing combination is performed. The method not only maintains the characteristics of the product, but also improves the yield and reduces the cost.

Description

Technical Field

[0001] This application relates to the field of inductor manufacturing, and more particularly to a method for manufacturing a copper-core inductor and the inductor itself. Background Technology

[0002] Copper-core inductors are high-performance inductor components that combine the advantages of magnetic core materials with embedded copper conductors, and are widely used in high-frequency and high-power applications. Structurally, the magnetic core provides high permeability to concentrate magnetic flux, while the embedded copper conductor forms a low-resistance coil, optimizing current distribution and reducing the skin effect.

[0003] Existing methods for manufacturing copper-embedded magnetic core inductors suffer from high costs and low yields. Summary of the Invention

[0004] This application provides a method for manufacturing a copper-core inductor and the inductor itself, aiming to improve yield and reduce costs while maintaining product characteristics.

[0005] The technical solution of this application is as follows:

[0006] In a first aspect, this application provides a method for manufacturing a copper-core inductor, comprising the following steps:

[0007] S1) Prepare soft magnetic materials and copper conductors.

[0008] The soft magnetic material is a soft magnetic alloy powder with added adhesive.

[0009] The copper conductor includes a first component, a second component, and a third component connected in sequence. The first component and the third component are bent in the same direction relative to the second component. The included angle between the first component and the second component is α1, and the included angle between the third component and the second component is α2. 90°≤α1≤180°, 90°≤α2≤180°.

[0010] S2) Fabrication of magnetic core preform

[0011] Soft magnetic materials are pressed using a cold pressing process to form a monolithic magnetic core preform. Along the pressing direction, the magnetic core preform includes a first surface and a second surface that are parallel to each other, and a mounting groove is formed within the magnetic core preform. The mounting groove includes a horizontal groove, a first vertical groove, and a second vertical groove. The horizontal groove opens onto the first surface and extends parallel to the first surface. The first and second vertical grooves connect to the two ends of the horizontal groove, and extend perpendicularly to the first surface, passing through the second surface.

[0012] S3) Implanted copper conductor

[0013] Along the pressing direction, the copper conductor is inserted into the mounting groove to form the inductor preform. The second component is embedded in the horizontal groove, the first component is inserted into the first vertical groove, and the third component is inserted into the second vertical groove. The portion of the copper conductor in the mounting groove is in contact with the groove wall. S4) A hot-pressing process is used to perform a secondary pressing on the inductor preform formed in step S3), tightly bonding the copper conductor and the magnetic core preform to form the inductor body. After subsequent processing, the finished inductor is obtained. The pressing direction in the hot-pressing process is the same as the pressing direction in the cold-pressing process.

[0014] Based on the method for manufacturing a copper-embedded magnetic core inductor provided in the first aspect, this method employs relatively mature cold pressing and hot pressing processes, improving product yield. Furthermore, through ingenious design, the magnetic core preform is configured as a single-piece structure, with mounting grooves adapted to the copper conductor formed within it. Thus, during the secondary pressing process using hot pressing, the magnetic core preform, possessing sufficient structural strength, prevents the copper sheet from shifting or tilting within the preform, improving electrical performance. In addition, the fabrication of the same inductor avoids multiple magnetic core preforms, thus eliminating the phenomenon of inconsistent densities and helping to prevent cracks or splitting at the joints of multiple preforms. Moreover, the density of the magnetic core in the finished inductor is uniform, which is beneficial for improving inductor performance. This application uses a single-piece magnetic core preform, requiring only one cold pressing and one hot pressing for the same inductor. In contrast, existing technologies require multiple cold pressing processes for multiple magnetic core preforms. Therefore, compared with the prior art, the inductor manufacturing method of this application significantly improves manufacturing efficiency and shortens manufacturing time.

[0015] In one possible design, in step S3), the surface of the second component that is opposite to the bending direction of the first component is flush with the first surface.

[0016] Based on the inductor manufacturing method provided in this embodiment, after the copper conductor is placed in the mounting groove, the surface of the second component of the copper conductor facing away from the bending direction of the first component is flush with the first surface. Thus, during the secondary pressing process in step S4), the copper conductor and the integral prefabricated magnetic core can simultaneously be subjected to equal pressure. This uniform pressure not only ensures a tight bond between the two but also effectively reduces contact resistance and improves overall electrical performance.

[0017] In one possible design, in step S3), the end of the first component away from the first surface extends out of the first vertical groove, and the end of the third component away from the first surface extends out of the second vertical groove.

[0018] Based on the inductor manufacturing method provided in this embodiment, after the copper conductor is placed in the mounting slot, the end of the first component away from the first surface extends out of the first vertical slot, and the end of the third component away from the first surface extends out of the second vertical slot. After pressing, the magnetic flux area of ​​the product can be increased, thereby improving the inductance of the product and optimizing its design.

[0019] In one possible design, in step S2), the cold pressing process employs gradient pressure, sequentially including a pre-pressing stage, a main pressing stage, and a final pressing stage. The pressure per unit area in the pre-pressing stage is 2.5-3.7 T / cm². 2 The pressure per unit area during the main pressure stage is 5.0-7.5 T / cm. 2 The pressure per unit area during the final compression stage is 8.7-10.0 T / cm. 2 .

[0020] Based on the inductor manufacturing method provided by this embodiment, in the cold pressing process, gradient pressure is mainly used to increase the density of the magnetic core preform. The higher the density of the magnetic core, the lower the product loss, and at the same time, the magnetic flux density can be better guaranteed, and the electrical properties and structure of the magnetic core are more stable.

[0021] In one possible design, in step S4), the hot pressing process employs gradient pressure, including a pressurization preheating stage and a main pressure stage.

[0022] The pressurization and preheating stage is used to soften the adhesive in the soft magnetic material, and the initial pressure allows the soft magnetic material to better fill the mold and remove air.

[0023] The pressure in the main pressure stage is greater than the initial pressure, and the temperature in the main pressure stage is greater than the temperature in the pressurization and preheating stage. This is used to further compress the soft magnetic alloy powder, promote the mechanical interlocking and plastic deformation between the soft magnetic alloy powders, and complete the dynamic recrystallization and dense bonding of the soft magnetic alloy powder.

[0024] Based on the inductor manufacturing method provided in this embodiment, a preliminary pressure is applied during the preheating process. This pressure is relatively gentle, allowing the magnetic powder to better fill the mold and reducing voids between particles. This process not only helps to expel air as much as possible but also prevents residual air in the soft magnetic alloy powder from forming pores or delamination defects after compression during subsequent compression. Furthermore, since the preliminary pressure is used before the main compression stage, density abrupt changes can be significantly reduced during the main compression stage, thereby effectively reducing internal stress concentration and ensuring the structural stability and performance consistency of the final product.

[0025] In one possible design, after the main pressure stage in step S4), there is a release stage where the pressure and temperature are lower than those of the main pressure stage, in order to reduce pressure and temperature before demolding and reduce the release of internal stress.

[0026] Based on the inductor manufacturing method provided by this embodiment, during the slow release stage, by gradually reducing the pressure and temperature, the release of internal stress can be slowly reduced, reducing product cracking and expansion after demolding, and stabilizing the product's density, dimensions, etc. as much as possible, thereby improving the overall quality and performance of the product.

[0027] In one possible design, the pressure per unit area during the pressurization preheating stage is 7.5-10.0 T / cm². 2 The pressure per unit area during the main pressure stage is 11.2-15.0 T / cm. 2 The pressure per unit area during the slow-release phase is 5.0-7.5 T / cm. 2 .

[0028] Based on the inductor manufacturing method provided in this embodiment, the manufactured inductor has high density, good inductance value and yield.

[0029] In one possible design, subsequent processes include a first coating and a second coating of the inductor body.

[0030] The material sprayed in the first coat is an insulating material, and the material sprayed in the second coat is a conductive material.

[0031] Based on the inductor manufacturing method provided in this embodiment, the second coating uses conductive materials, such as materials containing carbon nanotubes and graphene. These materials can enhance the magnetic shielding effect of the product, reduce magnetic field leakage, and improve the product performance stability.

[0032] In one possible design, after the second coating, there is a step of peeling off a portion of the coating layer at a corresponding position on the first surface to expose at least a portion of the copper conductor, and a step of electroplating at the peeled-off portion of the coating layer.

[0033] Based on the inductor manufacturing method provided in this embodiment, after secondary spraying, a portion of the coating is peeled off at a corresponding position on the first surface to expose at least a portion of the copper conductor, which is then electroplated. This enhances the inductor's heat dissipation performance, effectively reduces residual losses, and improves overall efficiency and stability.

[0034] Secondly, based on the same inventive concept, this application also provides an inductor manufactured using the aforementioned method for manufacturing a copper-core inductor. The beneficial effects of the inductor provided in the second aspect can be found in the first aspect and the beneficial effects of various possible embodiments of the first aspect, and will not be repeated here. Attached Figure Description

[0035] Figure 1 A schematic diagram of the structure of the copper conductor prepared in step S1) of the embodiment of this application.

[0036] Figure 2 This is a three-dimensional structural diagram of the magnetic core preform formed in step S2).

[0037] Figure 3 for Figure 2 Top view.

[0038] Figure 4 for Figure 3 AA cross-section view.

[0039] Figure 5 This is a schematic diagram of the state of implanting the copper conductor in step S3).

[0040] Figure 6 This is a schematic diagram of the structure of the inductor body formed in step S4).

[0041] Figure 7 This is a schematic diagram of the structure of the inductor body after one and two spray coatings.

[0042] Figure 8 This is a schematic diagram of the inductor body structure after a portion of the coating is peeled off at a corresponding position on the first surface of the magnetic core, exposing a portion of the copper conductor.

[0043] Figure 9 This is a schematic diagram of the inductor body after electroplating at the coating peeling area.

[0044] Figure 10 for Figure 1 The front view of the copper conductor shown.

[0045] Figure 11 for Figure 1 The top view of the copper conductor shown.

[0046] The attached figures are labeled as follows:

[0047] 1. Copper conductor; 11. First component; 12. Second component; 13. Third component;

[0048] 2. Magnetic core preform; 2A. First surface; 2B. Second surface; 21. Horizontal groove; 22. First vertical groove; 23. Second vertical groove;

[0049] 3. Inductor body; 4. Spray coating; 5. Electroplating layer. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and drawings of this application are intended to cover non-exclusive inclusion.

[0052] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0053] The technical solution of this application will be described in detail below, starting from the background technology of this application.

[0054] Currently, copper-core inductors are mainly manufactured using copper-iron co-firing technology. The specific steps are as follows: First, copper conductors are implanted into a mold, then soft magnetic material is filled and pressed to form the desired shape. Next, the product is sintered in a high-temperature furnace, followed by impregnation and baking. Then, the product dimensions are polished to the required specifications, and processes such as spraying, paint peeling, electroplating, bonding, and electrical performance testing are carried out in sequence.

[0055] The main shortcomings of this process are as follows:

[0056] 1) The technology is not yet mature, and the current first-pass yield rate on the market is about 50% to 70%.

[0057] 2) Products are prone to cracking after high-temperature sintering.

[0058] 3) During pressing, the soft magnetic material and the copper sheet are pressed into shape at the same time. From the side, it is easy for the copper sheet to tilt, which affects its magnetic circuit and leads to unstable electrical properties of the product.

[0059] 4) The cost of raw materials is relatively high (soft magnetic materials such as iron-nickel and iron-silicon-aluminum are mainly used in the market).

[0060] 5) It uses hazardous gases, such as hydrogen.

[0061] In another existing technology, the fabrication of copper-core inductors is carried out through cold pressing and hot pressing processes. Specifically, multiple core preforms are fabricated separately using the cold pressing process, and then the copper conductor is combined with the multiple core preforms using the hot pressing process. This technology uses multiple core preforms, and the density of these preforms will vary, which will lead to the following adverse effects:

[0062] 1) During the hot pressing process, cracks and fissures are prone to occur at the joints of magnetic core preforms of different densities.

[0063] 2) The number of magnetic core preforms is large, the assembly is difficult, and the dimensional accuracy requirements for the magnetic core preforms and copper conductors are high.

[0064] 3) If the same inductor has multiple magnetic cores of different densities, the characteristics of the inductor are unstable and fluctuate greatly.

[0065] Given the shortcomings of existing copper-core inductors, such as low yield, high cost, or unstable inductance characteristics, this application proposes an improved manufacturing method that aims to reduce manufacturing difficulty and cost while maintaining product characteristics.

[0066] Figure 1 This is a schematic diagram of the structure of the copper conductor prepared in step S1) of the embodiments of this application. Figure 2 This is a three-dimensional structural diagram of the magnetic core preform formed in step S2). Figure 3 for Figure 2 Top view, Figure 4 for Figure 3 AA section view, Figure 5 This is a schematic diagram showing the state of the copper conductor being implanted in step S3). Figure 6 This is a schematic diagram of the structure of the inductor body formed in step S4).

[0067] Please refer to Figures 1 to 6 The method for manufacturing a copper-core inductor provided in this application includes the following steps:

[0068] S1) Prepare soft magnetic materials and copper conductors.

[0069] The soft magnetic material is a soft magnetic alloy powder with added adhesive.

[0070] The copper conductor 1 includes a first component 11, a second component 12, and a third component 13 connected in sequence. The first component 11 and the third component 13 are bent in the same direction relative to the second component 12. The included angle between the first component 11 and the second component 12 is α1, and the included angle between the third component 13 and the second component 12 is α2. 90°≤α1≤180°, 90°≤α2≤180°.

[0071] S2) Fabrication of magnetic core preform 2

[0072] The soft magnetic material is pressed using a cold pressing process to form a one-piece magnetic core preform 2. Along the pressing direction, the magnetic core preform 2 includes a first surface 2A and a second surface 2B that are parallel to each other, and a mounting groove is formed within the magnetic core preform 2. The mounting groove includes a horizontal groove 21, a first vertical groove 22, and a second vertical groove 23. The horizontal groove 21 opens onto the first surface 2A and extends parallel to the first surface 2A. The first vertical groove 22 and the second vertical groove 23 connect to the two ends of the horizontal groove 21, and extend perpendicularly to the first surface 2A, penetrating from the first surface 2A to the second surface 2B.

[0073] S3) Implanted copper conductor 1

[0074] Along the pressing direction, the copper conductor 1 is inserted into the mounting groove to form an inductor preform. The second component 12 is embedded in the horizontal groove 21, the first component 11 is inserted into the first vertical groove 22, and the third component 13 is inserted into the second vertical groove 23. The part of the copper conductor 1 located in the mounting groove is in contact with the groove wall of the mounting groove.

[0075] S4) A hot-pressing process is used to perform a secondary pressing of the inductor preform formed in step S3), so that the copper conductor 1 and the magnetic core preform 2 are tightly bonded to form the inductor body 3. After subsequent processing, the finished inductor is obtained. The pressing direction in the hot-pressing process is the same as the pressing direction in the cold-pressing process.

[0076] Please combine Figures 1 to 6 The method for manufacturing a copper-embedded magnetic core inductor provided in this application has the following characteristics:

[0077] 1. High Yield: Compared to the copper-iron co-firing process, this application employs more mature processes, such as cold pressing and hot pressing. Cold pressing involves using pressure to compact soft magnetic material powder (such as iron-silicon, iron-nickel, amorphous or nanocrystalline alloy powder, etc.) into a predetermined shape. Hot pressing uses a hot press to simultaneously heat and pressurize, eliminating porosity and enhancing interfacial bonding between the copper conductor 1 and the magnetic core preform 2 under thermo-coupling, thereby improving density and performance. The overall process is relatively mature, and the first-pass yield is expected to reach 90%–95%.

[0078] 2. Lower cost while maintaining product characteristics: Iron-nickel alloy powder and iron-silicon alloy powder are relatively expensive, costing 150 to 300 yuan per kilogram, while amorphous or nanocrystalline alloy powder is cheaper, costing approximately 60 to 75 yuan per kilogram. The copper-iron process better utilizes the performance of iron-nickel alloy powder and iron-silicon alloy powder. Inductors manufactured using iron-nickel alloy powder and a copper-iron co-firing process achieve efficiencies of 70% to 75%. However, using the method described in this application, inductors can be manufactured using amorphous or nanocrystalline alloy powder with efficiencies of approximately 66% to 72%, similar to the former. Therefore, with essentially the same product characteristics, using the process described in this application can reduce costs.

[0079] 3. Stable Product Characteristics: A prominent feature of the manufacturing process provided in this application is that, through ingenious design, the magnetic core preform 2 is configured as a single-piece structure, and a mounting groove adapted to the copper conductor 1 is formed within the single-piece magnetic core preform 2. This brings the following beneficial effects to the manufacturing of the copper-embedded magnetic core inductor and the characteristics of the finished inductor:

[0080] Firstly, the magnetic core preform 2 is formed through a cold pressing process. After cold pressing, the magnetic core preform 2 possesses a certain structural strength. When the copper conductor 1 is implanted, a secondary pressing process using hot pressing is performed. The magnetic core preform 2, with its structural strength, can prevent the copper sheet from shifting or tilting within the magnetic core preform 2, thus improving electrical performance. Therefore, the inductor manufacturing method provided in this application has the advantage of preventing copper sheet tilting compared to the first prior art, which is beneficial for improving the electrical performance of the inductor.

[0081] Secondly, the magnetic core preform 2 is a single, integrated preform. For the fabrication of the same inductor, there are no multiple preforms, thus eliminating the problem of inconsistent densities among them and helping to prevent cracks or splitting at the joints. Furthermore, the finished inductor has a uniform core density, resulting in more stable inductance characteristics compared to the second existing technology.

[0082] 4. Short manufacturing cycle and high production efficiency: This application uses an integrated magnetic core preform 2, requiring only one cold pressing and one hot pressing for the same inductor. In contrast, existing technologies require multiple cold pressings for multiple magnetic core preforms. Therefore, compared with existing technologies, the inductor manufacturing method of this application significantly improves manufacturing efficiency and shortens manufacturing time.

[0083] It should be noted that, Figures 2 to 4 The shape of the magnetic core shown is only one specific embodiment of this application. In other embodiments of this application, the magnetic core may have other shapes.

[0084] It should also be noted that the method for manufacturing the copper-core inductor provided in this application can also be applied to other products with similar structures. For example, in some cases, the coil material can also be other conductive metals, such as silver.

[0085] In one embodiment of this application, in step S3), the surface 121 of the second component 12 facing away from the bending direction of the first component 11 is flush with the first surface 2A.

[0086] Specifically, please combine Figure 5 and Figure 6 When the copper conductor 1 is placed in the mounting slot, the surface of the second component 12 of the copper conductor 1 facing away from the bending direction of the first component 11 is flush with the first surface 2A. Thus, during the secondary pressing process in step S4), the copper conductor 1 and the integrated prefabricated magnetic core are simultaneously subjected to equal pressure. This uniform pressure not only ensures a tight bond between the two but also effectively reduces contact resistance and improves overall electrical performance. Furthermore, this synchronous pressing method avoids material deformation or damage caused by uneven pressure, thereby ensuring the stability and reliability of the product.

[0087] In one embodiment of this application, in step S3), the end of the first component 11 away from the first surface 2A extends out of the first vertical groove 22, and the end of the third component 13 away from the first surface 2A extends out of the second vertical groove 23.

[0088] For details, please refer to [link / reference]. Figure 5 and Figure 6 When the copper conductor 1 is placed in the mounting slot, the end of the first component 11 away from the first surface 2A extends out of the first vertical slot 22, and the end of the third component 13 away from the first surface 2A extends out of the second vertical slot 23. That is, the height of the copper conductor 1 must be greater than the height of the magnetic core preform 2. After pressing, the magnetic flux area of ​​the product (Φ = B·S, where Φ represents magnetic flux, B represents magnetic induction intensity, and S represents the area through which magnetic lines of force pass) can be increased, thereby improving the inductance of the product and optimizing its design.

[0089] In one embodiment of this application, in step S2), the cold pressing process employs gradient pressure, sequentially including a pre-pressing stage, a main pressing stage, and a final pressing stage. The pressure per unit area during the pre-pressing stage is 2.5-3.7 T / cm². 2 The pressure per unit area during the main pressure stage is 5.0-7.5 T / cm. 2 The pressure per unit area during the final compression stage is 8.7-10.0 T / cm. 2 .

[0090] Specifically, in the cold pressing process, gradient pressure is mainly used to increase the density of the magnetic core preform 2. The pre-pressing stage is used to initially eliminate the gaps between loose particles and reduce the porosity of subsequent pressurization. The main pressing stage achieves material densification, and the final pressing stage stabilizes the compact size and eliminates elastic aftereffects.

[0091] The higher the density of the magnetic core, the lower the product loss, and the better the magnetic flux density can be guaranteed. The electrical properties and structure of the magnetic core are also more stable.

[0092] Furthermore, gradient pressure helps reduce internal stress concentration and residual stress. It also better matches the creep characteristics of the material, which is beneficial for improving process stability.

[0093] In one embodiment of this application, in step S4), the hot pressing process employs gradient pressure, including a pressurization and preheating stage and a main pressure stage.

[0094] The pressurization and preheating stage is used to soften the adhesive in the soft magnetic material, and the initial pressure allows the soft magnetic material to better fill the mold and remove air.

[0095] The pressure in the main pressure stage is greater than the initial pressure, and the temperature in the main pressure stage is greater than the temperature in the pressurization and preheating stage. This is used to further compress the soft magnetic alloy powder, promote the mechanical interlocking and plastic deformation between the soft magnetic alloy powders, and complete the dynamic recrystallization and dense bonding of the soft magnetic alloy powder.

[0096] Specifically, a preliminary pressure is applied during the preheating process. This pressure is relatively gentle, allowing the magnetic powder to better fill the mold and reducing voids between particles. This process not only helps to expel as much air as possible but also prevents residual air in the soft magnetic alloy powder from being compressed and forming pores or delamination defects during subsequent compression. Furthermore, since the preliminary pressure is used before the main compression stage, the density abrupt changes during the main compression stage are significantly reduced, thereby effectively reducing internal stress concentration and ensuring the structural stability and performance consistency of the final product.

[0097] In one embodiment of this application, step S4) further includes a release stage after the main pressure stage. The pressure of the release stage is lower than that of the main pressure stage, and the temperature of the release stage is lower than that of the main pressure stage. This is used to reduce the pressure and temperature before demolding and reduce the release of internal stress.

[0098] Specifically, the main compression stage involves high pressure, typically reaching 4-6 tons, and high temperature, generally between 150 and 200 degrees Celsius. This allows the material to flow fully and fill the mold under high pressure and high temperature. In the slow release stage, by gradually reducing the pressure and temperature, the release of internal stress can be slowed down, reducing product cracking and post-demolding expansion. This helps to stabilize the product's density and dimensions, thereby improving the overall quality and performance of the product.

[0099] In one embodiment of this application, the pressure per unit area during the pressurization preheating stage is 7.5-10.0 T / cm. 2 The pressure per unit area during the main pressure stage is 11.2-15.0 T / cm. 2 The pressure per unit area during the slow-release phase is 5.0-7.5 T / cm. 2 .

[0100] In practice, it has been found that when the machine pressure ranges from 3.0 to 4.0T during the preheating stage, from 4.5 to 6.0T during the main pressure stage, and from 2.0 to 3.0T during the slow release stage, the manufactured inductors exhibit higher density, better inductance, and higher yield. The following specific examples illustrate this.

[0101] In one embodiment of this application, subsequent processes include a first coating and a second coating on the inductor body 3. The material for the first coating is an insulating material, and the material for the second coating is a conductive material.

[0102] Specifically, after hot pressing, the manufacturing of the inductor also includes steps such as chamfering, spraying, grinding, varnish stripping, and electroplating. In existing technologies, the spraying process only coats the inductor surface with insulating varnish. However, this application includes two spraying processes. The second spraying uses conductive materials, such as materials containing carbon nanotubes and graphene. These materials can enhance the magnetic shielding effect of the product, reduce magnetic field leakage, and improve the product's performance stability.

[0103] Figure 7 This is a schematic diagram of the inductor body after one and two coats of spraying. Please refer to... Figure 6 and Figure 7 It is important to note that the electrode surface should be avoided during both the first and second coats. Figure 7 The intermediate coating 4 covers the exposed copper conductor 1 on the first surface 2A of the magnetic core. The first surface 2A of the magnetic core, which is also the first surface 2A of the magnetic core preform 2, is formed by hot pressing.

[0104] In one embodiment of this application, after the second coating, the process further includes a step of peeling off a portion of the coating layer 4 at a corresponding position on the first surface 2A to expose at least a portion of the copper conductor 1, and a step of electroplating the peeled portion of the coating layer 4.

[0105] Figure 8 This is a schematic diagram of the inductor body structure after a portion of the coating has been peeled off at a corresponding location on the first surface, exposing a portion of the copper conductor. Please refer to... Figure 7 and Figure 8 After peeling off part of the coating layer 4, not only the copper conductor 1 was exposed, but also part of the magnetic core was exposed. Figure 9 This is a schematic diagram of the inductor body after electroplating at the peeled-off area of ​​the spray coating.

[0106] Please continue to refer to this. Figure 8 and Figure 9 Specifically, the heat dissipation effect of metallic materials is limited by the insulation material. In this application, after secondary coating, a portion of the coating is peeled off at the corresponding position on the first surface 2A to expose at least a portion of the copper conductor 1, which is then electroplated to form an electroplated layer 5. This enhances the heat dissipation performance of the inductor, effectively reduces residual losses, and improves overall efficiency and stability.

[0107] Figure 10 for Figure 1 The front view of the copper conductor is shown. Figure 11 for Figure 1 The image shows a top view of the copper conductor. The following is in conjunction with the attached diagram. Figure 1-6 , Figure 10 and 11 Some specific embodiments of this application will be described in detail.

[0108] Example 1:

[0109] J1) Determine the shape and size requirements of the copper conductor 1 and the magnetic core preform 2.

[0110] Please combine Figure 1 , Figure 10 and Figure 11 The copper conductor 1 includes a first component 11, a second component 12, and a third component 13 connected in sequence. The first component 11 and the third component 13 are bent at 90° relative to the second component 12 in the same direction. The overall length L of the copper conductor is 4.4±0.05mm, the height H is 3.55±0.05mm, and the width W is 0.8±0.03mm. The length L1 of the first component 11 and the third component 13 is 1.1±0.05mm, and the distance D between the first component 11 and the third component 13 is 2.2±0.05mm.

[0111] The magnetic core preform 2 is rectangular in shape, with an overall length of 6.77±0.01mm, a width of 3.08±0.005mm, and a height of 3.25±0.03mm. An internal mounting groove adapted to the copper conductor 1 is provided, penetrating two large-area surfaces 2A and 2B of the rectangular prism. The shape of the mounting groove is adapted to the copper conductor 1 and includes a horizontal groove 21, a first vertical groove 22, and a second vertical groove 23. The horizontal groove 21 opens onto the first surface 2A and extends parallel to it. The first vertical groove 22 and the second vertical groove 23 connect to the two ends of the horizontal groove 21, extending perpendicularly to the first surface 2A and extending from the first surface 2A to the second surface 2B.

[0112] The second component 12 of the copper conductor 1 can be embedded in the horizontal groove 21, the first component 11 can be inserted into the first vertical groove 22, the third component 13 can be inserted into the second vertical groove 23, and the part of the copper conductor 1 located in the mounting groove can contact the groove wall of the mounting groove.

[0113] J2) Determine the structure and dimensions of the mold system used in the hot pressing and cold pressing processes based on the shape and size of the magnetic core preform 2.

[0114] J3) Prepare soft magnetic materials and copper conductors 1

[0115] The soft magnetic material is a soft magnetic alloy powder with added adhesive. The soft magnetic alloy powder is a nanocrystalline powder, and the main component of the adhesive is polyimide.

[0116] The copper conductor 1 determined in step J1) is formed by wire cutting or integral stamping.

[0117] J4) Fabrication of magnetic core preform 2

[0118] Adjust the relative position between the lower punch and the middle die of the servo press mold to form a preset height difference.

[0119] The soft magnetic material is evenly filled into the cavity formed by the middle mold and the lower punch.

[0120] First, use a machine pressure of 1.0T (pressure per unit area: 2.5T / cm²). 2 Press for 0.5 seconds, then adjust the pressure to 2.0T (pressure per unit area: 5.0T / cm²). 2 Hold the pressure for 2 seconds, then increase the pressure to 3.5T (pressure per unit area: 8.7T / cm²). 2 Hold the pressure for 0.5 seconds. Form the magnetic core preform 2 as determined in step J1).

[0121] J5) Implanted copper conductor 1

[0122] Along the pressing direction, the copper conductor 1 is inserted into the mounting groove to form an inductor preform. The second component 12 is embedded in the horizontal groove 21, the first component 11 is inserted into the first vertical groove 22, and the third component 13 is inserted into the second vertical groove 23. The part of the copper conductor 1 located in the mounting groove is in contact with the groove wall of the mounting groove.

[0123] J6) Hot pressing

[0124] The mold temperature is controlled at 150℃, and a machine pressure of 3.0T is used (pressure per unit area: 7.5T / cm²). 2 Hold the pressure for 20 seconds. Then adjust the mold temperature to 200℃ and the pressure to 4.5T (pressure per unit area: 11.2T / cm²). 2The holding time is 100 seconds. Demolding forms the inductor body 3.

[0125] J7) The inductor body 3 is subjected to processes such as chamfering, spraying, grinding, paint peeling and electroplating to obtain the finished inductor.

[0126] Comparative Example 1:

[0127] The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, no pressure was applied during the preheating stage in step S4), and the temperature of the mold was only controlled at 150°C and maintained at this temperature for 20 seconds. Subsequently, the main pressure was applied at a pressure of 11.2 T / cm². 2 The pressure holding time is 120 seconds.

[0128] Example 2:

[0129] The difference between Example 2 and Example 1 is that in Example 2, after the main pressure stage in step S4), a sustained-release stage is added, with a pressure of 5.0 T / cm². 2 The holding time is 30 seconds, and the mold temperature is 180℃.

[0130] Example 3:

[0131] The difference between Example 3 and Example 1 is that in step S4) of Example 3, different hot pressing parameters are selected compared to Example 1. In Example 3, during pressing, the temperature of the mold is first controlled at 150°C, and the pressure is 10.0 T / cm. 2 Apply pressure and hold for 20 seconds. Then adjust the mold temperature to 200℃ and the pressure to 15.0 T / cm. 2 The holding time is 100 seconds. Demolding forms the inductor body 3.

[0132] Comparative Example 2:

[0133] The difference between Comparative Example 2 and Example 3 is that in Comparative Example 2, no pressure was applied during the preheating stage in step S4), and the temperature of the mold was only controlled at 150°C and maintained at this temperature for 20 seconds. Subsequently, the main pressure was applied at a pressure of 15.0 T / cm². 2 The pressure holding time is 120 seconds.

[0134] Example 4:

[0135] The difference between Example 4 and Example 3 is that in Example 4, after the main pressure stage in step S4), a sustained-release stage is added, with a pressure of 7.5 T / cm². 2 The holding time is 30 seconds, and the mold temperature is 180℃.

[0136] Example 5:

[0137] The difference between Example 5 and Example 1 is that in step S2) of Example 5, 3.7T / cm is first used. 2 Apply pressure for 0.5 seconds, then adjust the pressure to 7.5 T / cm. 2 Hold the pressure for 2 seconds, then increase the pressure to 10.0 T / cm. 2 Hold pressure for 0.5 seconds. Form the magnetic core preform 2 as determined in step J1).

[0138] Comparative Example 3:

[0139] The difference between Comparative Example 3 and Example 1 is that in step S2) of Comparative Example 3, a single pressure of 5.0 T / cm is used. 2 Press 2S. Form the magnetic core preform 2 as determined in step J1).

[0140] Comparative Example 4:

[0141] The difference between Comparative Example 4 and Example 5 is that in Comparative Example 3, a single pressure of 7.5 T / cm is used in step S2). 2 Press 2S to form the magnetic core preform 2 determined in step J1).

[0142] During the fabrication of the inductor, the density and height dimensions of the magnetic core preforms 2 prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were measured.

[0143] The density and inductance value of the inductor bodies 3 prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were tested.

[0144] The density of the magnetic core preform 2 and the density of the inductor body 3 were both tested using the Archimedes' displacement method. The dimensions of the magnetic core preform 2 were measured using a height gauge. The inductance of the inductor body 3 was tested using impedance analysis. The test results are shown in Table 1.

[0145] Table 1:

[0146]

[0147] Test Result Analysis:

[0148] The inductor manufacturing methods of Example 1 and Comparative Example 1 are compared. The difference between Example 1 and Comparative Example 1 is that in Example 1, pressure is applied during the preheating stage of the hot pressing process, while in Comparative Example 1, only the temperature of the mold is controlled during the preheating stage of the hot pressing process, and no pressure is applied.

[0149] Comparing the density and inductance values ​​after hot pressing of Example 1 and Comparative Example 1, the inductor body produced in Example 1 has a better density and a higher inductance value. This indicates that applying pressure during the preheating stage is beneficial to increasing the density of the inductor body, thereby improving its inductance value.

[0150] Comparing the inductor manufacturing methods of Example 1 and Example 2, the difference between Example 2 and Example 1 is that Example 2 includes a slow-release stage after the main voltage stage.

[0151] Comparing the appearance of the inductor bodies produced in Example 1 and Example 2, the inductor body in Example 1 developed cracks on its side after demolding; while the inductor body in Example 2 had a smooth surface and no abnormalities after demolding.

[0152] By comparing the appearance of Example 1 and Example 2, it can be shown that in the hot pressing process, adding a slow release stage after the main pressing stage helps to prevent the inductor body from shrinking and cracking, and stabilizes the density and size of the product.

[0153] The inductor fabrication methods of Example 1 and Comparative Example 3 are compared. The difference between Example 1 and Comparative Example 3 is that Example 1 uses gradient pressure when fabricating the magnetic core preform using a cold pressing process, while Comparative Example 3 uses single pressure when fabricating the magnetic core preform using a cold pressing process.

[0154] Comparing the density values ​​of the magnetic core preforms prepared in Example 1 and Comparative Example 3, the density of the magnetic core preform prepared in Example 1 is higher than that of the magnetic core preform prepared in Comparative Example 3. This indicates that in the cold pressing process, the use of gradient pressure helps to increase the density of the magnetic core preform, which is conducive to improving the inductance value.

[0155] Comparing the dimensions of the magnetic core preforms produced in Example 1 and Comparative Example 3, the dimensions of the magnetic core preform produced in Example 1 are closer to the designed dimensions of the magnetic core preform, while the dimensions of the magnetic core preform produced in Comparative Example 3 are larger than those produced in Example 1. This indicates that in the cold pressing process, applying a final pressure with even greater pressure after the main pressure can reduce the expansion of the magnetic core preform after demolding and stabilize the dimensions of the magnetic core preform.

[0156] Example 3 and Comparative Example 2 form a comparative example, and the comparison results are similar to those of Example 1 and Comparative Example 1; Example 3 and Example 4 form a comparative example, and the comparison results are similar to those of Example 1 and Example 2; Example 5 and Comparative Example 4 form a comparative example, and the comparison results are similar to those of Example 5 and Comparative Example 3; these will not be repeated here.

[0157] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for manufacturing a copper-embedded magnetic core inductor, characterized in that, Includes the following steps: S1) Prepare soft magnetic materials and copper conductors. The soft magnetic material is a soft magnetic alloy powder with added adhesive material; The copper conductor includes a first component, a second component, and a third component connected in sequence. The first component and the third component are bent in the same direction relative to the second component. The included angle between the first component and the second component is α1, and the included angle between the third component and the second component is α2. 90°≤α1≤180°, 90°≤α2≤180°. S2) Fabrication of magnetic core preform The soft magnetic material is pressed using a cold pressing process to form an integral magnetic core preform. Along the pressing direction, the magnetic core preform includes a first surface and a second surface that are parallel to each other, and a mounting groove is formed in the magnetic core preform; the mounting groove includes a horizontal groove, a first vertical groove and a second vertical groove, the horizontal groove opens into the first surface and extends in a direction parallel to the first surface; the first vertical groove and the second vertical groove are connected to the two ends of the horizontal groove, the first vertical groove and the second vertical groove extend in a direction perpendicular to the first surface and extend from the first surface to the second surface; S3) Implanted copper conductor Along the pressing direction, the copper conductor is inserted into the mounting groove to form an inductor preform; wherein, the second component is embedded in the horizontal groove, the first component is inserted into the first vertical groove, the third component is inserted into the second vertical groove, and the portion of the copper conductor located in the mounting groove is in contact with the groove wall of the mounting groove; S4) A hot pressing process is used to perform a secondary pressing on the inductor preform formed in step S3), so that the copper conductor and the magnetic core preform are tightly bonded to form the inductor body. After subsequent processing, the finished inductor is obtained. The pressing direction in the hot pressing process is the same as the pressing direction in the cold pressing process.

2. The method for manufacturing a copper-embedded magnetic core inductor according to claim 1, characterized in that, In step S3), the surface of the second component that is away from the bending direction of the first component is flush with the first surface.

3. The method for manufacturing a copper-embedded magnetic core inductor according to claim 2, characterized in that, In step S3), the end of the first component that is away from the first surface extends out of the first vertical groove, and the end of the third component that is away from the first surface extends out of the second vertical groove.

4. The method for manufacturing a copper-embedded magnetic core inductor according to claim 1, characterized in that, In step S2), the cold pressing process employs gradient pressure, sequentially including a pre-pressing stage, a main pressing stage, and a final pressing stage. The pressure per unit area in the pre-pressing stage is 2.5-3.7 T / cm². 2 The pressure per unit area during the main pressure stage is 5.0-7.5 T / cm. 2 The pressure per unit area during the final compression stage is 8.7-10.0 T / cm. 2 .

5. The method for manufacturing a copper-embedded magnetic core inductor according to claim 1, characterized in that, In step S4), the hot pressing process uses gradient pressure, including a pressurization and preheating stage and a main pressure stage; The pressurization and preheating stage is used to soften the adhesive in the soft magnetic material, and the initial pressure allows the soft magnetic material to better fill the mold and remove air. The pressure in the main pressure stage is greater than the initial pressure, and the temperature in the main pressure stage is greater than the temperature in the pressurization and preheating stage. This is used to further compress the soft magnetic alloy powder, promote the mechanical interlocking and plastic deformation between the soft magnetic alloy powders, and complete the dynamic recrystallization and dense bonding of the soft magnetic alloy powder.

6. The method for manufacturing a copper-embedded magnetic core inductor according to claim 5, characterized in that, In step S4), a release stage is included after the main pressure stage. The pressure and temperature of the release stage are lower than those of the main pressure stage, which is used to reduce pressure and temperature before demolding and reduce the release of internal stress.

7. The method for manufacturing a copper-embedded magnetic core inductor according to claim 6, characterized in that, The pressure per unit area during the pressurization and preheating stage is 7.5-10.0 T / cm. 2 The pressure per unit area during the main pressure stage is 11.2-15.0 T / cm. 2 The pressure per unit area during the slow-release phase is 5.0-7.5 T / cm. 2 .

8. The method for manufacturing a copper-embedded magnetic core inductor according to claim 1, characterized in that, The subsequent processes include a first spray coating and a second spray coating on the inductor body; The material used for the first spraying is an insulating material, and the material used for the second spraying is a conductive material.

9. The method for manufacturing a copper-embedded magnetic core inductor according to claim 8, characterized in that, After the second coating, the process also includes the steps of peeling off a portion of the coating layer at a corresponding position on the first surface to expose at least a portion of the copper conductor, and electroplating the peeled portion of the coating layer.

10. The inductor manufactured by the method of manufacturing the copper-core inductor according to any one of claims 1 to 9.

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