Injection molding Pin inductor and preparation method and application thereof

Abstract

The invention relates to an injection-molded Pin inductor and a preparation method and application thereof, and the preparation method of the injection-molded Pin inductor comprises the following steps: (1) providing an inductor blank which comprises a magnetic body and a coil partially embedded in the magnetic body; and (2) fixing a Pin and the inductor blank obtained in the step (1) in an injection mold, injecting insulating resin, and performing post-treatment on an obtained injection-molded Pin inductor semi-finished product to obtain the injection-molded Pin inductor. The magnet and the Pin are integrally formed through the injection molding process, the manufacturing process is simple, the cost is low, and the performance stability and the production efficiency of the inductor are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chip inductor preparation, and in particular to an injection molded Pin inductor and a preparation method and application thereof. Background Art

[0002] Chip inductors are small inductors that are widely used in power filtering, signal processing, and radio frequency applications to store energy and suppress noise. Due to their small size, they are suitable for high-density circuit board design. Traditional chip inductors are mostly made using winding or thin film processes, which have problems such as complex manufacturing processes, high costs, and difficulty in further reducing their size. As chip packaging technology develops towards miniaturization and integration, the requirements for the size, performance, and cost of chip inductors are becoming increasingly higher.

[0003] There is a contradiction between the volume of the inductor and the volume of the pin. Within a limited volume, the larger the inductor volume, the better the performance, which requires the volume of the pin to be as small as possible. Traditional chip inductors use the method of assembling the pin and inductor after they are formed separately. The pin volume accounts for a large proportion, the assembly process is complicated, and the coplanarity of each pad is difficult to guarantee.

[0004] CN 110660559A discloses an inductor element housing, an inductor and a manufacturing method thereof, wherein the inductor element housing comprises a housing and pins, wherein the pins comprise a plurality of bottom pins and a plurality of side pins, wherein the bottom pins are arranged at the bottom of the housing, and the side pins are arranged at the side of the housing, wherein the bottom pins are arranged for mounting, and the side pins are arranged for wire winding welding of magnetic ring leads. CN 217333809 U discloses an integrally formed chip inductor and a DC-DC circuit, wherein the integrally formed chip inductor comprises a magnetic core, a winding inside the magnetic core and a plurality of pins, wherein the plurality of pins are metal coatings formed directly on the magnet. The coplanarity of the inductor electrodes, pins and magnetic core is better, and installation space is saved at the same time. Since the electroplated metal pins are formed directly on the magnetic core, the thickness of the metal coating can be effectively controlled, thereby avoiding the error caused by pasting the pin bracket in the prior art, and reducing the production process caused by pasting the pins. CN 217822327U discloses an inductor structure for a switching power supply, comprising an inductor and a base, wherein the base comprises a base, a coil PIN pin, a support plate and a signal PIN pin; the base is fixed to the outer surface of the inductor; the coil PIN pin is mounted on the base, the support plate is fixed to the upper surface of the base, and the signal PIN pin is mounted on the support plate. The above method combines the PIN pin and the inductor by forming them separately and then assembling them, which may result in the defects of complex assembly process, large volume occupied by the PIN pin or difficulty in ensuring the coplanarity of each pad.

[0005] Therefore, in view of the shortcomings of the prior art, there is an urgent need to provide a method for preparing a Pin inductor which has a simple process, low cost, can ensure the coplanarity of each pad, and improve the performance stability of the inductor. Summary of the invention

[0006] The purpose of the present invention is to provide an injection-molded Pin needle inductor and a preparation method and application thereof, wherein the inductor and the Pin needle are integrated into one by an injection molding process, thereby simplifying the manufacturing process, reducing costs, and improving the performance stability and production efficiency of the inductor.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing an injection molded Pin inductor, the preparation method comprising the following steps:

[0009] (1) providing an inductor blank, wherein the inductor blank includes a magnetic body and a coil partially embedded in the magnetic body;

[0010] (2) Fixing the pin and the inductor blank obtained in step (1) in an injection mold, injecting insulating resin, and post-processing the obtained injection-molded pin inductor semi-finished product to obtain the injection-molded pin inductor.

[0011] The preparation method of the injection-molded Pin needle inductor provided by the present invention solves the problems that the Pin needle volume accounts for a large proportion, the assembly process is complicated, and the coplanarity of each pad is difficult to ensure, which are caused by the traditional chip inductor adopting the Pin needle and the inductor to be separately molded and then assembled. The magnet and the Pin needle are integrated into one by the injection molding process, and the spraying step can be omitted. The manufacturing process is simple and the cost is low. By adopting an injection mold, the position accuracy of each pad of the inductor can be stably controlled, the coplanarity between the pads of the inductor can be ensured, and poor welding can be avoided. The preparation method effectively improves the performance stability and production efficiency of the inductor.

[0012] Preferably, providing the inductor blank in step (1) comprises uniformly mixing soft magnetic powder and granulation resin and then granulating them, and the obtained granulation powder and the coil are pressed integrally; wherein, based on the total mass percentage being 100wt%, the soft magnetic powder and the granulation resin comprise 70-98wt% of the soft magnetic powder and 2-30wt% of the granulation resin.

[0013] The mass percentage of the soft magnetic powder is 70-98wt%, for example, it can be 70wt%, 75wt%, 80wt%, 90wt%, 95wt% or 98wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] The mass percentage of the granulated resin is 2-30wt%, for example, it can be 2wt%, 5wt%, 10wt%, 20wt%, 25wt% or 30wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] In the present invention, the ratio of soft magnetic powder to granulation resin needs to be strictly controlled. If the ratio of granulation resin is too high, the inductance will be reduced, and if the ratio of granulation resin is too low, it will be difficult to form.

[0016] Preferably, the soft magnetic powder in step (1) comprises any one of Fe-Si, Fe-Si-Al, Fe-Si-Cr, Fe-Ni or ferrite, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of Fe-Si and Fe-Si-Al, a combination of Fe-Si-Cr, Fe-Ni and ferrite, or a combination of Fe-Si, Fe-Si-Al, Fe-Si-Cr, Fe-Ni and ferrite.

[0017] Preferably, the granulation resin in step (1) comprises any one of polyvinyl alcohol, polyvinyl butyral, polyacrylic resin or epoxy resin, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of polyvinyl alcohol and polyvinyl butyral, a combination of polyvinyl butyral, polyacrylic resin and epoxy resin, or a combination of polyvinyl alcohol, polyvinyl butyral, polyacrylic resin and epoxy resin.

[0018] Preferably, the granulation method in step (1) includes any one of extrusion granulation, swing granulation or spray granulation.

[0019] Preferably, the integral pressing method in step (1) includes pressing at room temperature or pressing at a temperature.

[0020] Preferably, the temperature of the heated pressing is less than 200°C, for example, it can be 190°C, 180°C, 170°C, 160°C or 150°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, the pressing at room temperature refers to pressing at a temperature of 15-30°C.

[0022] Preferably, after the integral pressing in step (1), the steps of annealing, infiltration and baking and curing are also carried out in sequence.

[0023] Preferably, the annealing temperature is 650-800°C, for example, 650°C, 680°C, 700°C, 750°C or 800°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] Preferably, the agent used for the impregnation comprises liquid epoxy resin.

[0025] Preferably, the material of the Pin needle in step (2) includes any one of copper, tin, aluminum, iron, silver or gold, or an alloy of at least two of them. Typical but non-limiting alloys include copper-tin alloy, aluminum-iron alloy or copper-tin-aluminum alloy, preferably copper.

[0026] Preferably, the Pin in step (2) includes any one of a signal Pin, a power Pin or a ground Pin.

[0027] Preferably, the insulating resin in step (2) is a thermoplastic resin, and the thermoplastic resin includes any one of polyvinyl alcohol, polyvinyl butyral, polyacrylic resin or liquid crystal resin, or a combination of at least two of them. Typical but non-limiting combinations include a combination of polyvinyl alcohol and polyvinyl butyral, a combination of polyvinyl butyral, polyacrylic resin and liquid crystal resin, or a combination of polyvinyl alcohol, polyvinyl butyral, polyacrylic resin and liquid crystal resin.

[0028] Preferably, the post-processing in step (2) includes laser paint stripping and electroplating performed sequentially.

[0029] As a preferred technical solution of the preparation method of the present invention, the preparation method comprises the following steps:

[0030] (1) Soft magnetic powder and granulation resin are uniformly mixed and then granulated, the obtained granulation powder and the coil are integrally pressed, and then annealed at 650-800° C., impregnated with liquid epoxy resin, and baked and cured to obtain an inductor blank; based on the total mass percentage of 100wt%, the soft magnetic powder and the granulation resin are 70-98wt% and 2-30wt% of the soft magnetic powder and the granulation resin; the integral pressing method includes pressing at room temperature or pressing at a temperature of less than 200° C.;

[0031] (2) The pin and the inductor blank obtained in step (1) are fixed in an injection mold, and thermoplastic resin is injected. The obtained injection-molded pin inductor semi-finished product is subjected to laser paint stripping and electroplating in sequence to obtain the injection-molded pin inductor.

[0032] In a second aspect, the present invention provides an injection-molded Pin inductor, which is prepared by the preparation method of the injection-molded Pin inductor described in the first aspect.

[0033] The injection-molded Pin inductor provided by the present invention has good performance stability and can meet the high performance requirements of a chip inductor.

[0034] In a third aspect, the present invention provides an application of the injection-molded Pin inductor as described in the second aspect, wherein the injection-molded Pin inductor is used in a GPU power module or a CPU power module.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The preparation method of the injection-molded Pin needle inductor provided by the present invention solves the problems that the Pin needle volume accounts for a large proportion, the assembly process is complicated, and the coplanarity of each pad is difficult to ensure, which are caused by the traditional chip inductor adopting the Pin needle and the inductor to be separately molded and then assembled. The magnet and the Pin needle are integrated into one by the injection molding process, and the spraying step can be omitted. The manufacturing process is simple and the cost is low. By adopting an injection mold, the position accuracy of each pad of the inductor can be stably controlled, the coplanarity between the pads of the inductor can be ensured, and poor welding can be avoided. The preparation method effectively improves the performance stability and production efficiency of the inductor. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the positions of the signal copper pin and the inductor blank provided in Example 1 of the present invention;

[0038] Figure 2 It is a schematic diagram of a semi-finished injection-molded Pin inductor provided in Embodiment 1 of the present invention;

[0039] Figure 3 It is a schematic diagram of the positions of the signal copper pin and the inductor blank provided in Example 8 of the present invention;

[0040] Figure 4 It is a schematic diagram of a semi-finished injection-molded Pin inductor provided in Embodiment 8 of the present invention;

[0041] Among them: 1, inductor body; 2, signal copper pin; 3, liquid crystal resin. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0043] Example 1

[0044] This embodiment provides an injection-molded Pin inductor, and the preparation method of the injection-molded Pin inductor includes the following steps:

[0045] (1) Fe-Si-Al soft magnetic powder and epoxy resin are uniformly mixed and then subjected to swing granulation, the obtained granulated powder and the coil are pressed at room temperature, and then annealed at 700° C., impregnated with liquid epoxy resin, and baked and cured to obtain an inductor blank 1; based on the total mass percentage being 100wt%, the Fe-Si-Al soft magnetic powder and the epoxy resin are 95wt% and 5wt% respectively;

[0046] (2) Fix the signal copper pin 2 and the inductor blank 1 obtained in step (1) in an injection mold. The position diagram of the signal copper pin 2 and the inductor blank 1 is shown in FIG. Figure 1 As shown, the liquid crystal resin 3 is then injected, and the schematic diagram of the obtained injection molded Pin inductor semi-finished product is as shown Figure 2 As shown, the semi-finished product of the injection-molded Pin needle inductor is sequentially subjected to laser paint stripping and electroplating to obtain the injection-molded Pin needle inductor.

[0047] Example 2

[0048] This embodiment provides an injection-molded Pin inductor, and the preparation method of the injection-molded Pin inductor includes the following steps:

[0049] (1) Fe-Si soft magnetic powder and polyacrylic acid resin are uniformly mixed and then extruded and granulated, the obtained granulated powder and the coil are pressed at room temperature, and then annealed at 650° C., impregnated with liquid epoxy resin, and baked and cured to obtain an inductor body 1; based on the total mass percentage of 100wt%, the Fe-Si soft magnetic powder and the polyacrylic acid resin are 70wt% and 30wt% respectively;

[0050] (2) The signal aluminum pin and the inductor blank 1 obtained in step (1) are fixed in an injection mold, polyvinyl alcohol is injected, and the obtained injection-molded pin inductor semi-finished product is subjected to laser paint stripping and electroplating in sequence to obtain the injection-molded pin inductor.

[0051] Example 3

[0052] This embodiment provides an injection-molded Pin inductor, and the preparation method of the injection-molded Pin inductor includes the following steps:

[0053] (1) Fe-Si-Cr soft magnetic powder and polyvinyl alcohol are uniformly mixed and then subjected to swing granulation, the obtained granulated powder and the coil are pressed at room temperature, and then annealed at 800° C., impregnated with liquid epoxy resin, and baked and cured to obtain an inductor blank 1; based on the total mass percentage of 100wt%, the Fe-Si-Cr soft magnetic powder and the epoxy resin contain 98wt% of the Fe-Si-Cr soft magnetic powder and 2wt% of the epoxy resin;

[0054] (2) The signal iron pin and the inductor blank 1 obtained in step (1) are fixed in an injection mold, and polyacrylic resin is injected. The obtained injection-molded pin inductor semi-finished product is subjected to laser paint stripping and electroplating in sequence to obtain the injection-molded pin inductor.

[0055] Example 4

[0056] This embodiment provides an injection molded Pin inductor. The difference between the preparation method of the injection molded Pin inductor and that of Embodiment 1 is that, except that the mass percentage of the Fe-Si-Al soft magnetic powder in step (1) is adjusted to 65wt%, and the mass percentage of the epoxy resin is adjusted to 35wt%, the rest is the same as that of Embodiment 1.

[0057] Example 5

[0058] This embodiment provides an injection molded Pin inductor. The difference between the preparation method of the injection molded Pin inductor and that of Embodiment 1 is that, except that the mass percentage of the Fe-Si-Al soft magnetic powder in step (1) is adjusted to 99wt% and the mass percentage of the epoxy resin is adjusted to 1wt%, the rest is the same as that of Embodiment 1.

[0059] Example 6

[0060] This embodiment provides an injection molded Pin inductor. The difference between the preparation method of the injection molded Pin inductor and that of Embodiment 1 is that, except that the granulated powder and the coil in step (1) are adjusted to 180° C. for heating and pressing, the rest is the same as that of Embodiment 1.

[0061] Example 7

[0062] This embodiment provides an injection molded Pin inductor. The difference between the preparation method of the injection molded Pin inductor and that of Embodiment 1 is that step (1) does not include the steps of annealing, liquid epoxy resin infiltration, and baking and curing, and the rest is the same as that of Embodiment 1.

[0063] Example 8

[0064] This embodiment provides an injection molded Pin inductor. The difference between the preparation method of the injection molded Pin inductor and that of Embodiment 1 is that step (2) is: fixing the signal copper Pin 2 and the inductor blank 1 obtained in step (1) in an injection mold. The position diagram of the signal copper Pin 2 and the inductor blank 1 is shown in FIG. Figure 3 As shown, the signal copper pins 2 are simultaneously injection molded on multiple sides of the inductor blank 1, and then the liquid crystal resin 3 is injected. The schematic diagram of the obtained injection molded Pin inductor semi-finished product is as shown in FIG. Figure 4 As shown, the rest are the same as in Example 1.

[0065] In this embodiment, pins can be injection-molded around the inductor blank at the same time, thereby improving production efficiency.

[0066] Comparative Example 1

[0067] This comparative example provides a chip inductor, which adopts the integrated chip inductor disclosed in CN 217333809 U.

[0068] In the above-mentioned integrated chip inductor, the metal plating layer is directly formed on the magnet on the pin needle, and the coplanarity yield of the pin needle and the magnetic core is lower than that of Example 1, and only one side can be injection molded at a time, so the production efficiency is low.

[0069] The injection molded Pin inductors provided in Examples 1-7 and the chip inductors provided in Comparative Example 1 were tested for coplanarity using a 3D profilometer, and the yield was calculated based on the test results. The magnetic permeability and magnet power loss were tested using a BH tester, and the results are shown in Table 1.

[0070] Table 1

[0071]

[0072] It can be seen from Table 1 that the injection molded Pin inductor provided by the present invention has a high pad coplanarity yield and good comprehensive magnetic properties;

[0073] By comparing Example 1 with Examples 4 and 5, it can be seen that if the content of epoxy resin is too high, the magnetic permeability of the injection-molded Pin inductor will be significantly reduced, and if the content is too low, the power loss of the magnet will be increased; by comparing Example 1 with Example 7, it can be seen that the process is relatively simple without the annealing step, but it will lead to defects such as large coercive force of the magnet and high power loss of the magnet;

[0074] By comparing Example 1 with Comparative Example 1, it can be seen that Comparative Example 1 can only injection mold one side at a time, and the production efficiency is low and the coplanarity yield is low.

[0075] In summary, the preparation method of the injection-molded Pin needle inductor provided by the present invention solves the problems of large Pin needle volume proportion, complex assembly process and difficulty in ensuring the coplanarity of each pad caused by the traditional chip inductor that the Pin needle and the inductor are separately molded and assembled. The magnet and the Pin needle are integrated into one by the injection molding process, and the spraying step can be omitted. The manufacturing process is simple and the cost is low. By adopting an injection mold, the position accuracy of each pad of the inductor can be stably controlled, the coplanarity between the pads of the inductor can be ensured, and poor welding can be avoided. The preparation method effectively improves the performance stability and production efficiency of the inductor.

[0076] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing an injection molded Pin inductor, characterized in that: The preparation method comprises the following steps: (1) providing an inductor blank, wherein the inductor blank includes a magnetic body and a coil partially embedded in the magnetic body; (2) Fixing the pin and the inductor blank obtained in step (1) in an injection mold, injecting insulating resin, and post-processing the obtained injection-molded pin inductor semi-finished product to obtain the injection-molded pin inductor.

2. The preparation method according to claim 1, characterized in that: Providing the inductor blank in step (1) includes uniformly mixing soft magnetic powder and granulation resin and then granulating them, and the obtained granulation powder and the coil are pressed together; wherein, based on the total mass percentage of 100wt%, the soft magnetic powder and the granulation resin include 70-98wt% of the soft magnetic powder and 2-30wt% of the granulation resin.

3. The preparation method according to claim 2, characterized in that: The soft magnetic powder in step (1) comprises any one of Fe-Si, Fe-Si-Al, Fe-Si-Cr, Fe-Ni or ferrite, or a combination of at least two thereof; Preferably, the granulation resin in step (1) comprises any one of polyvinyl alcohol, polyvinyl butyral, polyacrylic resin or epoxy resin, or a combination of at least two thereof.

4. The preparation method according to any one of claims 1 to 3, characterized in that The granulation method in step (1) includes any one of extrusion granulation, swing granulation or spray granulation; Preferably, the integral pressing method in step (1) includes pressing at room temperature or pressing at a temperature; Preferably, the temperature of the heated pressing is less than 200°C.

5. The preparation method according to any one of claims 1 to 4, characterized in that: After the integral pressing in step (1), the method further includes the steps of annealing, impregnation and baking and curing in sequence; Preferably, the annealing temperature is 650-800°C; Preferably, the agent used for the impregnation comprises liquid epoxy resin.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The material of the pin in step (2) includes any one of copper, tin, aluminum, iron, silver or gold or an alloy of at least two of them, preferably copper; Preferably, the Pin in step (2) includes any one of a signal Pin, a power Pin or a ground Pin; Preferably, the insulating resin in step (2) is a thermoplastic resin, and the thermoplastic resin includes any one of polyvinyl alcohol, polyvinyl butyral, polyacrylic resin or liquid crystal resin, or a combination of at least two thereof.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The post-processing in step (2) includes laser paint stripping and electroplating performed in sequence.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) Soft magnetic powder and granulation resin are uniformly mixed and then granulated, the obtained granulation powder and the coil are integrally pressed, and then annealed at 650-800° C., impregnated with liquid epoxy resin, and baked and cured to obtain an inductor blank; based on the total mass percentage of 100wt%, the soft magnetic powder and the granulation resin are 70-98wt% and 2-30wt% of the soft magnetic powder and the granulation resin; the integral pressing method includes pressing at room temperature or pressing at a temperature of less than 200° C.; (2) Fixing the pin and the inductor blank obtained in step (1) in an injection mold, injecting thermoplastic resin, and sequentially subjecting the obtained injection-molded pin inductor semi-finished product to laser paint stripping and electroplating to obtain the injection-molded pin inductor.

9. An injection molded Pin inductor, characterized in that: The injection-molded Pin inductor is prepared by the method for preparing the injection-molded Pin inductor according to any one of claims 1 to 8.

10. An application of the injection molded Pin inductor as claimed in claim 9, characterized in that: The injection-molded Pin inductor is used in a GPU power module or a CPU power module.

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