Module inductor and manufacturing method thereof

Abstract

The invention discloses a manufacturing method of a modular inductor. The manufacturing method comprises the following steps: selecting and preprocessing an inductor; accurate paint stripping is carried out; carrying out multi-layer nano composite electroplating; performing AOI (automatic optical inspection); fixing the ceramic-based jig; sPI detection is carried out; mounting the device; reflow soldering; finished product detection. The invention also comprises a module inductor, the welding surface, the short side surface and the bottom surface of the rectangular inductor form a continuous conductive layer through accurate paint stripping and multilayer nano composite electroplating, and the long side surface keeps an original insulating paint layer to avoid short circuit of adjacent devices; the multilayer nano composite electroplated layer comprises a bottom layer plated copper, a middle layer nickel-graphene nano composite plated layer and a surface layer tinned tin in sequence from inside to outside, and the bottom layer plated copper ensures high conductivity and reduces conduction loss; the nickel-graphene nano-composite plating layer in the middle layer improves the overall hardness and corrosion resistance of the plating layer and enhances the binding force with the upper layer and the lower layer at the same time; the tin plating on the surface layer optimizes the welding wettability and ensures the firm connection between the electronic element and the inductance carrier.

Description

Technical Field

[0001] This invention relates to the field of electronic component manufacturing technology, and in particular to a modular inductor and its manufacturing method. Background Technology

[0002] An inductor is a component that can convert electrical energy into magnetic energy and store it. It has a wide range of applications in various industries.

[0003] As PCBA board design evolves towards smaller size, higher efficiency, better heat dissipation, and higher integration, the traditional design approach of soldering capacitors and inductors separately onto the PCBA board has significant drawbacks: First, independent components occupy a large space, limiting the integration of the PCBA board; second, the long interconnection lines between components result in significant energy loss, affecting device battery life and increasing heat dissipation pressure; third, capacitors are mostly packaged with organic materials, resulting in poor heat dissipation performance and susceptibility to overheating failure during long-term operation; fourth, the independent soldering process is cumbersome, production efficiency is low, and the long signal transmission path leads to poor high-frequency performance and signal integrity. Therefore, this invention proposes a modular inductor and its manufacturing method. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a modular inductor and its manufacturing method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A modular inductor includes a carrier, wherein the carrier is a rectangular inductor, and electronic components are soldered onto the surface of the carrier, wherein the electronic components and the carrier form a module, and the electronic components include, but are not limited to, capacitors, resistors and MOSFETs.

[0007] A method for manufacturing a modular inductor includes the following steps:

[0008] Step 1: Inductor selection and preprocessing: Select a rectangular inductor as the carrier, and define the inductor's welding surface, bottom surface (parallel to the welding surface), long side surface (perpendicular to the welding surface and with a large area), and short side surface (perpendicular to the welding surface and with a small area).

[0009] Step 2, Precise Paint Stripping: The inductor is placed in a customized laser paint stripping machine, and the paint is stripped only on the solder surface, short side surface and bottom surface, while the insulating paint layer on the long side surface is preserved. The paint stripping process uses pulsed laser mode with a laser wavelength of 355nm and a pulse width of 5~10ns. Depending on the material of the inductor body, various forms such as purple light, red light and green light can be selected to strip the paint layer of specific areas on the surface, avoiding overheating damage to the inductor substrate.

[0010] Step 3, Multi-layer nanocomposite electroplating: The welded surface, short side and bottom surface after paint stripping are subjected to multi-layer nanocomposite electroplating treatment, which includes copper plating at the bottom layer, nickel-graphene nanocomposite plating in the middle layer and tin plating on the surface layer to form a conductive welded layer with high conductivity and high adhesion. In the nickel-graphene nanocomposite plating, the graphene is uniformly dispersed in the plating solution through ultrasonic dispersion process.

[0011] Step 4, AOI Inspection: The flatness and parallelism of the coating are inspected using AOI equipment. There should be no obvious pits, bumps or coating defects, and the coplanarity test should meet the product usage requirements.

[0012] Step 5, Fixing the ceramic-based fixture and printing solder paste: A special inductor solder paste printing and fixing fixture made of ceramic-based high-temperature resistant positioning material is used. The ceramic-based material is alumina-zirconia composite ceramic. The fixture uses a double fixing structure of vacuum adsorption and positioning pins to position and fix the bottom and short sides of the inductor respectively. Solder paste is printed on the fixed bottom and short sides using a customized stencil. If it is necessary to integrate devices on the electrode surface, a manual soldering station is reserved for the subsequent process.

[0013] Step 6, SPI Inspection: The height, volume, and area of ​​the printed solder paste are inspected using SPI inspection equipment. The solder paste height deviation is ≤±5%, the volume deviation is ≤±10%, and the area coverage is ≥95% to ensure compliance with the soldering process requirements. Defective products are reprinted.

[0014] Step 7, Component mounting: Electronic components are mounted onto the plated surface of the inductor. Several components are mounted on the short side and the bottom side respectively. The electronic components are capacitors, resistors and MOSFETs. The mounting process is assisted by a vision positioning system.

[0015] Step 8, Reflow Soldering: Place the mounted inductors in a reflow oven and solder them according to the preset temperature profile. The temperature profile is as follows: preheating zone 60~120℃, constant temperature zone 120~150℃, reflow zone 210~260℃, cooling zone ≤80℃. Nitrogen gas is introduced for protection during the soldering process. The nitrogen purity is ≥99.99% and the oxygen content is ≤300ppm.

[0016] Step 9, Finished Product Inspection: Conduct electrical performance and appearance inspections on the products using customized testing equipment. The on-resistance value is in the milliohm range, and the deviation of electronic component parameters is ≤±5%. Defective products are returned for repair or scrapped.

[0017] Preferably, the inductor material is selected from FeNi alloy soft magnetic material, FeSi alloy soft magnetic material, FeSiAL alloy soft magnetic material, amorphous soft magnetic material, nanocrystalline soft magnetic material, ferrite soft magnetic material, etc. Among them, ferrite inductors have high permeability and low loss characteristics, which are suitable for low and medium frequency operating scenarios, while amorphous alloy inductors have better high frequency response and temperature stability, which can meet the requirements of high frequency circuit design. The inductor needs to undergo appearance cleaning treatment to remove surface oil, dust and other impurities to avoid affecting the stability of subsequent paint stripping and electroplating processes.

[0018] Preferably, the total thickness of the multilayer nanocomposite electroplating is strictly controlled at 5~15μm, with the bottom copper plating layer at 3~8μm to reduce current transmission loss by utilizing the high conductivity of copper; the middle nickel-graphene nanocomposite plating layer at 1~4μm to improve the overall performance of the plating layer through the reinforcing effect of graphene; and the surface tin plating layer at 1~3μm to ensure good wetting and reliable connection during the welding process.

[0019] Preferably, the preparation steps of the plating solution for the nickel-graphene nanocomposite coating are as follows:

[0020] Preparation of basic plating solution: Add nickel sulfate, nickel chloride and boric acid to deionized water in sequence, stir until completely dissolved, and control the concentration of nickel sulfate to 200~250g / L, the concentration of nickel chloride to 30~50g / L and the concentration of boric acid to 30~40g / L to form the basic plating solution;

[0021] Preparation of graphene dispersion: Polyethylene glycol dispersant is added to deionized water, stirred and dissolved, and then graphene powder is added to prepare a graphene dispersion with a concentration of 0.1~0.5 g / L. Polyethylene glycol molecules are adsorbed on the surface of graphene sheets to form steric hindrance.

[0022] Ultrasonic dispersion treatment: Place the graphene dispersion in an ultrasonic device with a power of 100~200W and disperse for 30~60 minutes to ensure that the thickness of the graphene sheets is ≤5nm and there is no obvious agglomeration.

[0023] Mixing and volume adjustment: The ultrasonically dispersed graphene dispersion is slowly added to the base plating solution at a ratio of 5~15mL / L, and stirred continuously for 30min. Then, it is adjusted to the required volume with deionized water, allowed to stand for 10min, and then filtered to obtain the plating solution for preparing nickel-graphene nanocomposite coating.

[0024] Preferably, the positioning pin of the ceramic-based fixture is made of zirconia ceramic, and the preparation steps of the zirconia ceramic material are as follows:

[0025] Raw material ratio: Take 94-97% zirconium oxide powder, 3-6% yttrium oxide powder and 0.5-1% alumina powder by weight percentage, mix them evenly, add anhydrous ethanol as dispersion medium, ball mill for 24-36 hours, ball-to-material ratio 10:1, and grind until the powder particle size is ≤1μm;

[0026] Molding process: Spray dry the ball-milled slurry with an inlet air temperature of 180~200℃ and an outlet air temperature of 80~90℃ to obtain a free-flowing powder. Use cold isostatic pressing to form a blank for the positioning pin with a molding pressure of 150~200MPa and a holding pressure of 5~10min.

[0027] Degreasing and sintering: The green body is placed in a degreasing furnace and heated to 600~800℃ in an air atmosphere, and held for 2~3 hours to remove organic impurities; then it is transferred to a sintering furnace and held at 1550~1650℃ for 4~6 hours, and then naturally cooled to room temperature to form a dense ceramic body.

[0028] Precision machining: The ceramic blank is turned and ground using a diamond grinding wheel, with the diameter of the locating pin controlled at 1~2mm and the surface roughness Ra≤0.02μm;

[0029] Performance optimization: The processed locating pins are ultrasonically cleaned at a power of 100~150W for 10~15min to remove surface impurities, and then dried at 200~300℃ for 1~2h to finally obtain zirconia ceramic locating pins with a hardness of HV≥1200 and a high temperature resistance of ≥300℃.

[0030] Preferably, the electronic component mounting process is assisted by a visual positioning system using a CCD camera and image recognition algorithm. The CCD camera acquires the reference mark on the inductor plating surface and the image of the component mounting position. The image recognition algorithm performs coordinate calibration and deviation compensation. The positioning speed is ≤0.5s / piece, which meets the efficiency requirements of industrial mass production. The repeatability positioning accuracy is ≤±0.03mm, ensuring that the electronic components are accurately mounted in the solder paste printing area and avoiding defects such as misalignment and cold solder joints.

[0031] Preferably, the nickel-graphene nanocomposite coating achieves a performance leap through a nano-reinforcement mechanism, with a microhardness ≥500HV, which is more than 40% higher than that of traditional pure nickel coating. It can effectively resist mechanical wear during mounting, welding and use, and has a salt spray corrosion resistance ≥500h, making it suitable for humid and highly corrosive working environments.

[0032] Preferably, the activation treatment uses a 5-10% concentration of dilute sulfuric acid solution as the activator, the soaking time is controlled at 1-2 minutes, and the soaking temperature is maintained at 20-25°C to avoid abnormal surface roughness caused by high temperature or long soaking time. After the activation treatment, the surface is rinsed with deionized water 3-5 times to thoroughly remove residual acid and impurities, ensuring that the coating forms a strong metallurgical bond with the inductor substrate.

[0033] Preferably, the design of the customized stencil is matched with the inductor mounting, and the mesh size is customized according to the shape and size of the electronic component pins to ensure that the solder paste printing amount is compatible with the pin soldering requirements; the mesh wall thickness is set to 0.08~0.12mm, and the mesh edges are rounded with a radius of 0.01~0.02mm to avoid solder paste residue on the mesh edges during the printing process and reduce the phenomenon of clogging.

[0034] The present invention has the following beneficial effects:

[0035] 1. Through a gradient composition nickel-graphene composite coating, the "low-high-low" graphene content distribution ensures high conductivity on the surface layer, while the intermediate layer achieves microhardness ≥550HV thanks to its high graphene content. Simultaneously, a two-step activation process achieves zero adhesion, resolving the triangular contradiction of "conductivity-wear resistance-adhesion." Atomic layer deposition (ALD) assisted electroplating, with a transition layer and a 10nm copper seed layer design, controls the coating thickness deviation to ±0.1μm, resulting in graphene sheet thickness ≤3nm without agglomeration and high-frequency impedance ≤3Ω, meeting the high-frequency operating requirements of high-end electronic devices. Furthermore, a low-chromium environmentally friendly plating solution system achieves salt spray corrosion resistance ≥600h under cyanide-free and lead-free environmental conditions, with a welding wetting angle ≤30°, without affecting the reliability of subsequent device mounting.

[0036] 2. Through the modular design of the ceramic-based fixture, the positioning module can be quickly replaced, adapting to inductors of all sizes from 3 to 8mm. The integrated solder paste printing and mounting process reduces the production cycle to ≤20s / piece, improving efficiency. Online SPI detection is linked with the MES system, enabling real-time traceability of detection data, improving process consistency, and automatically sorting defective products, reducing manual re-inspection costs. The ultra-precision automated process in Example 4, from femtosecond laser stripping to piezoelectric ceramic mounting, requires no manual intervention, improving batch production yield and reducing quality losses. Furthermore, the environmentally friendly process utilizes recycled cleaning agents and activators, and recovers heavy metals from the plating solution, reducing material waste and wastewater treatment costs.

[0037] 3. Core processes such as laser paint stripping, electroplating, and reflow soldering can utilize existing equipment. Upgrades can be achieved simply by optimizing parameters and replacing customized components, reducing enterprise technology upgrade costs. Furthermore, process parameters are flexibly adjustable, allowing for rapid adaptation to different customers' inductor specifications and device types, resulting in fast mass production response. In addition, the graphene dispersion, ceramic-based materials, and environmentally friendly plating solutions used in the process are all commercially available and mature materials with a stable supply chain, eliminating reliance on special consumables and ensuring large-scale deployment. Attached Figure Description

[0038] Figure 1 This diagram illustrates the synergistic effect of the multilayer nanocomposite electroplating layer in the manufacturing method of the module inductor proposed in this invention.

[0039] Figure 2 This is a front view of the modular inductor proposed in this invention. Detailed Implementation

[0040] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0041] Example 1: Optimization of Gradient Composition Nickel-Graphene Composite Electroplating Process

[0042] By regulating the gradient distribution of graphene content along the coating thickness direction, the conductive and mechanical properties of the coating are synergistically improved, while the positioning accuracy compensation mechanism of the ceramic-based fixture is optimized.

[0043] Inductor selection and pretreatment: A standard rectangular inductor with dimensions of 5mm-6mm-8mm (LWH) and ferrite material was selected. The pretreatment adopted a composite process of "plasma cleaning + anhydrous ethanol ultrasonic cleaning". The plasma cleaning power was 800W and the time was 3min to remove organic contaminants and oxide film from the surface. Then, anhydrous ethanol ultrasonic cleaning was performed for 8min. The drying temperature was 60℃ and the time was 25min to ensure that the surface roughness Ra≤0.1μm.

[0044] Precise paint stripping: The customized laser paint stripping machine adopts a dual-beam collaborative paint stripping process. The main beam (wavelength 355nm, pulse width 5ns) is responsible for stripping the main paint layer, while the auxiliary beam (wavelength 532nm, pulse width 8ns) is responsible for the fine edge processing. The laser power is 4W and 2W respectively, the paint stripping speed is 10mm / s, and the focused spot diameter is 40μm, ensuring that there are no burrs on the edge of the stripped surface and the transition radius is ≤0.05mm.

[0045] Gradient composition multilayer nanocomposite electroplating: A two-step activation process is adopted, first immersing in 5% dilute sulfuric acid solution for 1 min (20℃), then immersing in 0.5% hydrochloric acid solution for 30 s (20℃), rinsing with deionized water 4 times, and then drying for 10 min before entering the electroplating process to improve the adhesion between the coating and the substrate. The bottom copper plating layer (3μm) plating solution is composed of nickel sulfate 200g / L, nickel chloride 30g / L, and boric acid 30g / L; the middle nickel-graphene composite plating layer (3μm) is divided into three layers along the thickness direction. The first layer (1μm) contains 0.8wt% graphene (8mL / L graphene dispersion, 0.2g / L polyethylene glycol), the second layer (1μm) contains 1.5wt% graphene (12mL / L graphene dispersion, 0.3g / L polyethylene glycol), and the third layer (1μm) contains 0.8wt% graphene, forming a "low-high-low" gradient distribution; the surface tin plating layer (2μm) plating solution consists of 150g / L stannous sulfate, 40g / L sulfuric acid, and 5mL / L additives;

[0046] Furthermore, a segmented ultrasonic dispersion process was adopted. The ultrasonic power was 100W during the bottom layer electroplating, 150~200W during the intermediate layer gradient electroplating (increasing synchronously with the increase of graphene content), and 80W during the surface layer electroplating. The dispersion time was 30min for all layers. The electroplating current density gradient was adjusted as follows: 1.2A / dm² for the bottom layer, 1.5~1.8A / dm² for the intermediate layer, and 1.0A / dm² for the surface layer. The electroplating temperature was 26~28℃, and the pH value of the plating solution was 4.8~5.0. After electroplating, the plating solution was ultrasonically cleaned with deionized water for 5min, followed by drying at 120℃ for 10min to remove residual plating solution and moisture.

[0047] AOI inspection: Using 3D-AOI inspection equipment, the flatness error of the coating is ≤0.01mm and the parallelism error is ≤0.02mm. The coating cross-section is analyzed by line scanning electron microscopy (SEM) to confirm that the graphene gradient distribution is uniform, there is no agglomeration, and there are no gaps at the interface between the coating and the substrate.

[0048] Dynamic positioning optimization of ceramic-based fixtures: The fixture material is alumina-zirconia-silicon carbide composite ceramic (mass ratio 60%:30%:10%), with a coefficient of thermal expansion of 3.5×10⁻ 6 / ℃, high temperature resistance up to 380℃, the thermal conductivity of the fixture is improved by adding silicon carbide particles, with a thermal conductivity ≥30W / (m・K), the positioning structure adopts the "positioning pin + elastic compensation pad" design, the positioning pin diameter is 1.5mm, the fitting gap is 0.005mm, the elastic compensation pad is made of polyimide, the thickness is 0.1mm, the compression amount is 0.02~0.03mm, which can compensate for the positioning deviation caused by the inductor size tolerance;

[0049] SPI Inspection: High-precision SPI equipment is used to inspect solder paste height to 0.09mm, with height deviation ≤±2%, volume deviation ≤±5%, and area coverage ≥99%. 3D contour scanning confirms that there are no collapsed edges or bridging phenomena in the solder paste printing.

[0050] Component placement: Chip capacitors (size 0.5mm0.3mm0.3mm) are selected. The placement adopts a dual closed-loop control of "visual positioning + pressure feedback". The placement pressure is 0.02MPa and the positioning accuracy is ±0.002mm. After placement, the component placement firmness is detected by a pressure sensor and the feedback pressure is ≥0.015MPa.

[0051] Reflow soldering: Nitrogen-protected reflow soldering is used, with nitrogen purity of 99.996% and oxygen content ≤25ppm. The temperature profile adopts a "slow rise-constant temperature-rapid cooling" mode: preheating zone 60~120℃ (2.5min), constant temperature zone 130~150℃ (1.5min), reflow zone 220℃ (35s), cooling zone ≤60℃ (1.5min), cooling rate 5℃ / s, to reduce thermal stress on the plating and components;

[0052] Finished product inspection: In electrical performance testing, the conduction resistance is ≤0.07Ω, the capacitance value deviation is ≤±2%, the microhardness of the coating is ≥550HV, and the adhesion grade is 0 (100-cross test); the reliability test includes thermal shock (-40℃~125℃, 500 cycles), with no coating peeling and no loosening of the components;

[0053] Tape and reel packaging: Anti-static and moisture-proof tape is used. The product is treated with ion air to remove static electricity before packaging. The humidity of the packaging environment is ≤50%. Each roll contains 300 pieces and has a built-in humidity indicator card.

[0054] Furthermore, through gradient composition electroplating and dynamic positioning fixture design, the conductivity of the plating layer is increased by 20%, the mechanical strength by 30%, and the positioning accuracy by 40%, significantly optimizing the overall performance of the module inductor.

[0055] Example 2: Modular Integration Process of Ceramic-Based Fixtures

[0056] The modular design and multi-process integration of ceramic-based fixtures improve manufacturing efficiency and process consistency through modular fixture functions and integrated solder paste printing-mount design, while optimizing the pulse electroplating process of nanocomposite electroplating.

[0057] Inductor selection and pretreatment: A rectangular inductor with dimensions of 6mm-7mm-9mm (LWH) and amorphous alloy material was selected. The pretreatment adopted a four-step process: alkaline cleaning (pH=9.5) → acid neutralization (1% dilute sulfuric acid) → deionized water rinsing → drying. The alkaline cleaning time was 10 minutes, and the drying temperature was 70℃ for 30 minutes to ensure that there were no residual impurities on the surface.

[0058] Precise paint stripping: The laser paint stripping machine adopts automated program control, presets the paint stripping path according to the inductor size, has a pulse width of 7ns, a laser power of 5W, a paint stripping speed of 12mm / s, and a focused spot diameter of 50μm. During the paint stripping process, the inductor position information is collected in real time, and the laser parameters are dynamically adjusted. The paint stripping qualification rate is ≥99.8%.

[0059] Pulse-type multilayer nanocomposite electroplating: Immerse in 10% citric acid solution for 2 minutes (25℃), rinse 5 times with deionized water, and enter the electroplating process within 15 minutes after drying. Citric acid activation can reduce corrosion of the inductor substrate and improve the adhesion of the coating. The coating consists of 230 g / L nickel sulfate, 40 g / L nickel chloride, 35 g / L boric acid, and 12 mL / L graphene dispersion (the dispersant is polyethylene glycol-polypropylene glycol block copolymer, concentration 0.3 g / L). The graphene content is 1.5 wt%, and 0.5 g / L sodium dodecyl sulfate is added as a leveling agent to improve the surface smoothness of the coating.

[0060] Furthermore, a dual-pulse electroplating mode was adopted, with a forward pulse current density of 2.0 A / dm² and a pulse width of 20 ms, a reverse pulse current density of 0.5 A / dm² and a pulse width of 5 ms, a duty cycle of 70%, an electroplating temperature of 28℃, a plating solution pH of 5.0, and a total coating thickness of 12 μm (copper coating 6 μm, nickel-graphene composite coating 3 μm, and tin coating 3 μm).

[0061] In addition, ultrasonic vibration is activated throughout the electroplating process, with a power of 150W and a frequency of 40kHz, to promote plating solution convection, reduce concentration polarization, and improve coating uniformity.

[0062] AOI inspection: The flatness error of the coating is ≤0.015mm, the parallelism error is ≤0.025mm, and the coating composition is detected by X-ray fluorescence spectroscopy (XRF) to confirm that the nickel, graphene, and tin contents meet the design requirements, and the coating thickness deviation is ≤±5%.

[0063] Modular design of ceramic-based fixture: The fixture consists of a positioning module, a printing module, and a support module. These modules are connected by precision bolts. The positioning module is replaceable and adaptable to inductors ranging from 3 to 8 mm in size. Replacement time is ≤5 minutes. The positioning module is made of zirconia ceramic with a coefficient of thermal expansion of 2.8 × 10⁻⁻⁻⁴. 6 / ℃, the positioning pin is made of tungsten carbide material, with surface nitriding treatment, hardness ≥HV1500, and service life ≥50,000 times;

[0064] Furthermore, the printing module integrates a customized stencil, with the stencil and positioning module designed as a single unit. The stencil has a mesh size of 0.5mm*0.25mm, a mesh wall thickness of 0.1mm, and a corner radius of 0.015mm. The stencil is electrochemically polished, with a surface roughness Ra≤0.01μm, reducing solder paste residue. The support module has a built-in temperature sensor to monitor the fixture temperature in real time during the printing process, with temperature fluctuations ≤±1℃, avoiding positioning deviations caused by temperature changes.

[0065] SPI testing: An online SPI device is used, with a testing speed of 15 pieces / min, a solder paste height of 0.10mm, a height deviation of ≤±3%, a volume deviation of ≤±7%, and an area coverage of ≥98%. The test data is uploaded to the MES system in real time to achieve quality traceability.

[0066] Integrated component placement: The placement head and fixture positioning module are linked, and the placement head is automatically calibrated through the reference mark on the fixture. The placement speed is 0.3s / piece, the repeatability is ±0.003mm, and visual inspection is performed immediately after placement. Defective products are automatically marked and sorted.

[0067] Reflow soldering: A hot air reflow oven is used with a nitrogen flow rate of 6 m³ / h and an oxygen content of ≤30 ppm. The temperature profile is as follows: preheating zone 80~120℃ (2 min), constant temperature zone 130~150℃ (1 min), reflow zone 225℃ (38 s), and cooling zone ≤70℃ (1 min). During the soldering process, the inductor surface temperature is monitored in real time by an infrared thermometer to ensure temperature uniformity ≤±3℃.

[0068] Finished product inspection: Electrical performance testing includes conductivity, impedance, and insulation resistance. Conductivity is ≤0.09Ω and insulation resistance is ≥100MΩ. Appearance inspection uses machine vision and manual re-inspection. Solder joints are free from cold solder joints and bridging, and plating is free from scratches and peeling. Reliability testing includes vibration testing (10~2000Hz, acceleration 8g, 10h).

[0069] Tape and reel packaging: Modular tape and reel machines are used, allowing for quick replacement of tape and reel molds according to product size. The tape and reel speed is 20 pieces / second. The packaging label contains information such as product model, batch number, production date, and test results, and is stored in QR code format for easy and quick retrieval.

[0070] Furthermore, through modular fixture design and process integration, production efficiency is increased by 35%, process consistency is improved to 99.7%, and production costs and quality risks are significantly reduced.

[0071] Example 3: Green and environmentally friendly nanocomposite electroplating process

[0072] The manufacturing process adopts a cyanide-free, low-chromium plating solution system, a matching recycling and treatment system, and optimizes the biodegradable coating design of ceramic-based fixtures to achieve an environmentally friendly manufacturing process.

[0073] Inductor selection and pretreatment: A rectangular inductor with dimensions of 4mm x 5mm x 7mm (LWH) and ferrite material was selected. Pretreatment used an environmentally friendly cleaning agent (mainly composed of surfactants and citrate esters), ultrasonically cleaned for 10 minutes at 40℃, followed by rinsing three times with deionized water, and drying at 65℃ for 25 minutes. The cleaning agent is recyclable with a recovery rate ≥90%.

[0074] Precise paint stripping: The UV laser paint stripping machine is used with a wavelength of 355nm, a pulse width of 6ns, a laser power of 4W, a paint stripping speed of 9mm / s, and a focused spot diameter of 40μm. The paint residue generated during the paint stripping process is collected by a negative pressure collection device and recycled after high-temperature degradation treatment to avoid environmental pollution.

[0075] Green multilayer nanocomposite electroplating: A fluorine-free activator (mainly composed of phosphoric acid and organic acid complex) at a concentration of 8% is used, with an immersion time of 1.2 minutes and a temperature of 23℃. The activator is recyclable and has a service life of ≥50 batches. The bottom copper plating layer uses a cyanide-free plating solution (mainly composed of 200g / L copper pyrophosphate, 300g / L potassium pyrophosphate, and 50g / L ammonium citrate), resulting in zero cyanide emissions. The middle nickel-graphene composite plating layer uses a low-chromium plating solution with a chromium content ≤0.5g / L. The plating solution composition is 220g / L nickel sulfate, 35g / L nickel chloride, 35g / L boric acid, and 10mL / L graphene dispersion (the dispersant is environmentally friendly polyglycerol fatty acid ester, concentration 0.2g / L), with a graphene content of 1.0wt%. The surface tin plating layer uses a lead-free plating solution (Sn-3.0Ag-0.5Cu), which complies with RoHS standards.

[0076] Furthermore, the current density is 1.0~1.5A / dm², the electroplating temperature is 25~27℃, the pH value of the plating solution is 4.5~4.8, and the total coating thickness is 8μm (4μm for copper plating, 2μm for nickel-graphene composite plating, and 2μm for tin plating). After filtration, ion exchange, evaporation and concentration treatment, more than 95% of the metal ions in the electroplating waste liquid can be recycled and reused.

[0077] AOI inspection: The flatness error of the coating is ≤0.012mm and the parallelism error is ≤0.022mm. Atomic absorption spectroscopy (AAS) is used to detect the content of heavy metal ions in the plating solution to ensure compliance with environmental protection standards and that there are no obvious defects on the coating surface.

[0078] Environmentally friendly coating optimization for ceramic-based fixtures: The fixture material is alumina-zirconia composite ceramic (70%:30% by mass), with a coefficient of thermal expansion of 4.2×10⁻ 6 / ℃, high temperature resistance up to 360℃, the fixture surface is coated with a biodegradable polylactic acid coating with a thickness of 0.05mm. The coating has good lubricity and wear resistance, with a coefficient of friction ≤0.1. After use, it can degrade in the natural environment with a degradation rate ≥90%.

[0079] In addition, the positioning structure adopts a "vacuum adsorption + magnetic assisted positioning" design. The positioning pin has a diameter of 1.2mm and a fitting gap of 0.006mm. The magnetic assisted positioning uses neodymium iron boron permanent magnets with a magnetic force of 0.5N to enhance positioning stability and avoid inductive damage caused by excessive mechanical pressure.

[0080] SPI testing: Environmentally friendly solder paste (lead-free, halogen-free) is used. The solder paste height is tested to be 0.08mm, with a height deviation of ≤±3%, a volume deviation of ≤±8%, an area coverage of ≥97%, and the heavy metal content in the solder paste meets the standards.

[0081] Component placement: Environmentally friendly chip resistors (size 0.4mm x 0.2mm x 0.2mm) are selected. Anti-static nozzles are used for placement, with a placement pressure of 0.015MPa and a positioning accuracy of ±0.003mm. Static electricity generated during the placement process is discharged through a grounding device, and the static voltage is ≤50V.

[0082] Reflow soldering: An energy-saving reflow oven is used, which reduces energy consumption by 20%. The nitrogen purity is 99.99% and the oxygen content is ≤40ppm. The temperature profile is as follows: preheating zone 70~110℃ (2min), constant temperature zone 120~140℃ (1min), reflow zone 215℃ (32s), cooling zone ≤75℃ (1min). The welding exhaust gas is treated by activated carbon adsorption before being discharged.

[0083] Finished product testing: In electrical performance testing, the conduction resistance is ≤0.08Ω, the resistance value deviation is ≤±3%, and the coating's salt spray corrosion resistance is ≥600h (neutral salt spray test); Environmental testing includes heavy metal content and volatile organic compound (VOC) content.

[0084] Tape and sling packaging: Biodegradable paper tape is used, the recycling rate of packaging materials is ≥95%, corrugated cardboard boxes are used for packing (no ink printing), and labels are printed with water-based inks, so there is no secondary pollution in the packaging process.

[0085] Furthermore, through green and environmentally friendly process design, the wastewater discharge in the electroplating process is reduced by 80%, and the heavy metal recycling rate is ≥95%, realizing the clean production of module inductors, which is in line with the trend of green manufacturing development.

[0086] Example 4: Ultra-precision nanocomposite electroplating and fixture adaptive process

[0087] By using atomic layer deposition-assisted electroplating and fixture adaptive compensation algorithms, micron-level coating thickness control and submicron-level positioning accuracy are achieved, meeting the requirements of high-precision manufacturing.

[0088] Inductor selection and pretreatment: An ultra-precision rectangular inductor with dimensions of 3mm x 4mm x 5mm (LWH) and made of amorphous alloy was selected. The pretreatment adopted the process of "plasma cleaning + atomic layer deposition (ALD) pretreatment". The plasma cleaning power was 1000W and the time was 5min. Then, an Al2O3 transition layer with a thickness of 5nm was deposited using ALD technology to improve the adhesion between the coating and the substrate. The deposition temperature was 150℃ and the deposition pressure was 10Pa.

[0089] Precise paint stripping: Employs a femtosecond laser paint stripping machine with a wavelength of 355nm, a pulse width of 100fs, a laser power of 3W, a paint stripping speed of 5mm / s, a focused spot diameter of 20μm, and a paint stripping accuracy of ±0.001mm, enabling micron-level paint layer stripping while avoiding damage to the substrate.

[0090] Ultra-precision multilayer nanocomposite electroplating: Utilizing atomic layer etching (ALE) activation technology with O2 as the etching gas, an etching time of 30 seconds, and an etching temperature of 80℃, this process precisely removes adsorbed impurities from the ALD transition layer surface without damaging it. The bottom copper plating layer employs a composite process of "atomic layer deposition + electroplating," first depositing a 10nm thick copper seed layer via ALD, then electroplating to thicken it to 3μm. The seed layer enhances the uniformity and adhesion of the plating layer. The intermediate nickel-graphene composite plating layer employs atomic layer dispersion technology, uniformly coating the copper plating surface with a 10nm thickness using atomic layer deposition equipment, followed by electroplating to thicken it to 2μm. The graphene content is 1.2wt%, ensuring uniform distribution of graphene sheets. The surface tin plating layer is electroplated to a thickness of 1μm.

[0091] In addition, a high-precision electroplating power supply is used, with a current accuracy of ±0.1mA / dm², an electroplating temperature control accuracy of ±0.1℃, a plating solution pH control accuracy of ±0.01, a total plating thickness of 5μm, and a thickness deviation of ≤±0.1μm. After electroplating, ion beam cleaning is performed with an ion beam energy of 500eV and a cleaning time of 2min to remove the oxide film and residual impurities on the plating surface. Then, it is vacuum dried at 100℃ for 5min with a vacuum degree of ≤1Pa.

[0092] AOI inspection: Using ultra-high precision 3D-AOI equipment, the flatness error of the coating is ≤0.005mm and the parallelism error is ≤0.01mm. The microstructure of the coating is analyzed by transmission electron microscopy (TEM), and the graphene sheet thickness is ≤3nm and the coating grain size is ≤50nm.

[0093] Ceramic-based fixture adaptive positioning technology: The fixture material is monocrystalline silicon reinforced alumina ceramic (monocrystalline silicon content 15%), with a coefficient of thermal expansion of 2.0×10⁻ 6 / ℃, high temperature resistance up to 400℃, dimensional accuracy ±0.001mm, ultra-high rigidity achieved through single crystal silicon reinforcement, elastic modulus ≥400GPa, the positioning system adopts "laser interferometric positioning + adaptive compensation algorithm", the laser interferometer measurement accuracy is ±0.01μm, real-time acquisition of inductor positioning deviation data, and adjustment of positioning pin position and adsorption pressure through adaptive algorithm, with compensation deviation ≤0.001mm;

[0094] In addition, the vacuum adsorption system adopts a microchannel design with an adsorption pore diameter of 0.2mm, an adsorption pressure of -0.07~-0.08MPa, and an adsorption force uniformity of ≤±0.001N, avoiding micro-deformation caused by inductance.

[0095] SPI testing: Using ultra-precision SPI equipment, the testing accuracy is ±0.001mm, the solder paste height is 0.08mm, the height deviation is ≤±1%, the volume deviation is ≤±3%, the area coverage is ≥99.5%, and the surface roughness of the solder paste Ra is ≤0.05μm as detected by atomic force microscopy (AFM).

[0096] Component mounting: Ultra-miniature chip capacitors (0.3mm x 0.2mm x 0.2mm) are selected. The mounting is carried out using a piezoelectric ceramic driven mounting head with a mounting pressure of 0.01MPa and a positioning accuracy of ±0.001mm. After mounting, the component mounting deviation is detected by a laser interferometer, and the deviation is ≤0.002mm.

[0097] Reflow soldering: An ultra-precision reflow oven is used with a temperature control accuracy of ±0.1℃, nitrogen purity of 99.999%, and oxygen content of ≤10ppm. Temperature profile: preheating zone 80~110℃ (2.5min), isothermal zone 130~145℃ (1.5min), reflow zone 210℃ (30s), cooling zone ≤60℃ (2min), cooling rate 2℃ / s, reducing device misalignment caused by thermal stress;

[0098] Finished product inspection: Electrical performance testing uses an ultra-precision LCR tester, with conduction resistance ≤0.07Ω, capacitance deviation ≤±1%, and high-frequency impedance (10GHz) ≤3Ω; Appearance inspection uses a scanning electron microscope (SEM) at 1000x magnification, with no cold solder joints or bridging, and no scratches or peeling of the plating; Reliability testing includes micro-vibration testing (10~10000Hz, acceleration 5g, 20h).

[0099] Tape and reel packaging: Ultra-precision tape and reel machine is used with tape and reel accuracy of ±0.002mm. The packaging adopts anti-static vacuum packaging, with built-in desiccant and humidity indicator card. The cleanliness of the packaging environment is ≥Class100.

[0100] Furthermore, through ultra-precision manufacturing processes and adaptive positioning technology, the coating thickness control accuracy reaches ±0.1μm, and the positioning accuracy reaches ±0.001mm, meeting the requirements of high-end electronic devices for ultra-precision module inductors.

[0101] Table 1: Comparison of Key Process Parameters for Each Embodiment

[0102] Key process parameters Example 1 Example 2 Example 3 Example 4 Total coating thickness 8μm 12μm 8μm 5μm Graphene content 0.8~1.5wt% 1.5wt% 1.0wt% 1.2wt% Nitrogen purity for reflow soldering 99.996% 99.99% 99.99% 99.999% Oxygen content of reflow solder ≤25ppm ≤30ppm ≤40ppm ≤10ppm

[0103] Table 2: Comparison of Accuracy Control Index Data for Each Embodiment

[0104] Precision control indicators Example 1 Example 2 Example 3 Example 4 Coating flatness error ≤0.01mm ≤0.015mm ≤0.012mm ≤0.005mm Coating parallelism error ≤0.02mm ≤0.025mm ≤0.022mm ≤0.01mm Solder paste height deviation ≤±2% ≤±3% ≤±3% ≤±1% Solder paste volume deviation ≤±5% ≤±7% ≤±8% ≤±3% Component mounting accuracy ±0.002mm ±0.003mm ±0.003mm ±0.001mm Coefficient of thermal expansion of jig <![CDATA[3.5×10⁻ 6 / ℃]]> <![CDATA[2.8×10⁻ 6 / ℃]]> <![CDATA[4.2×10⁻ 6 / ℃]]> <![CDATA[2.0×10⁻ 6 / ℃]]>

[0105] Table 3: Comparison of Core Performance Indicators for Each Embodiment

[0106] Core performance indicators Example 1 Example 2 Example 3 Example 4 On resistance ≤0.07Ω ≤0.09Ω ≤0.08Ω ≤0.07Ω Microhardness of coating ≥550HV ≥580HV ≥520HV ≥560HV Coating adhesion level Level 0 (100-grid test) Level 0 (100-grid test, to be completed) Level 0 (100-grid test) Level 0 (100-grid test) Insulation resistance ≥100MΩ ≥100MΩ ≥100MΩ ≥150MΩ High-frequency impedance (10GHz) ≤5Ω ≤6Ω ≤7Ω ≤3Ω

[0107] As can be seen from the table above, in traditional electroplating processes, it is often difficult to simultaneously achieve high conductivity, mechanical strength, and corrosion resistance in the plating layer (for example, increasing hardness can easily lead to a decrease in conductivity, and enhancing corrosion resistance requires sacrificing weldability). This invention achieves synergistic performance optimization through differentiated process design: The gradient composition nickel-graphene composite plating layer in Example 1, through a "low-high-low" graphene content distribution, maintains high conductivity on the surface of the plating layer (20% higher than traditional pure nickel plating layers), while the intermediate layer achieves microhardness ≥550HV (30% higher) thanks to its high graphene content. At the same time, the two-step activation process achieves adhesion level 0, resolving the triangular contradiction of "conductivity-wear resistance-adhesion".

[0108] Furthermore, the atomic layer deposition (ALD) assisted electroplating in Example 4, through the design of a transition layer and a 10nm copper seed layer, controls the coating thickness deviation within ±0.1μm, with a graphene sheet thickness ≤3nm and no agglomeration, and a high-frequency impedance (10GHz) ≤3Ω, which is 40% lower than that of traditional coatings, making it suitable for the high-frequency operation requirements of high-end electronic devices; the low-chromium environmentally friendly plating solution system in Example 3, under the premise of being cyanide-free and lead-free, achieves salt spray corrosion resistance ≥600h, far exceeding that of traditional coatings (≤300h), and the welding wetting angle ≤30°, without affecting the reliability of subsequent device mounting.

[0109] Furthermore, traditional manufacturing methods suffer from poor fixture versatility, independent process steps, and difficulty in inspection and traceability, resulting in long production cycles (≥60s / piece) and low pass rates (≤95%). This invention achieves a breakthrough in efficiency through process integration and automation optimization: Example 2 features a modular design for the ceramic-based fixture, allowing for rapid replacement of the positioning module (≤5min), adapting to 3~8mm full-size inductors, and integrating solder paste printing and mounting, reducing the production cycle to ≤20s / piece, improving efficiency by 35%; simultaneously, online SPI inspection is linked with the MES system, enabling real-time traceability of inspection data, improving process consistency to 99.7%, and automatically sorting defective products, reducing manual re-inspection costs. Example 4's ultra-precision automated process, from femtosecond laser stripping (accuracy ±0.001mm) to piezoelectric ceramic mounting (speed 0.3s / piece), requires no manual intervention throughout, achieving a batch production yield of ≥99.8%, reducing quality loss by 50% compared to traditional processes. In addition, the environmentally friendly process in Example 3 uses cleaning agents and activators in a recycling process (recovery rate ≥90%), and the heavy metal recovery rate of the plating solution is ≥95%, which not only reduces material waste but also lowers wastewater treatment costs, resulting in a 30% reduction in overall production costs.

[0110] Furthermore, the traditional modular inductor manufacturing process is rigid, making it difficult to simultaneously meet diverse needs such as high performance, miniaturization, and environmental friendliness, thus limiting its application scenarios. This invention achieves full-scenario coverage through differentiated process design: For high-performance scenarios such as high-frequency communication and industrial control, the gradient plating in Example 1 and the ultra-precision process in Example 4 respectively achieve high-frequency low-loss and micron-level precision control, making them compatible with 5G base stations, high-end PLCs, and other equipment; For harsh environments such as automotive electronics and outdoor equipment, the dual-pulse electroplating and tungsten carbide positioning pin design in Example 2 make the product resistant to vibration (10~2000Hz, acceleration 8g) and thermal shock (-40℃~125℃, 500 cycles) with no risk of failure; For the miniaturization needs of consumer electronics and portable devices, the ultra-precision process in Example 4 achieves inductor sizes as small as 3mm, 4mm, and 5mm, with device mounting accuracy of ±0.001mm, meeting the small-volume integration requirements of smart wearables and smartphones; For environmentally sensitive scenarios such as medical and new energy, the cyanide-free, low-chromium, and biodegradable packaging design in Example 3 complies with EU REACH and RoHS 2.0 standards, with heavy metal emissions ≤2mg / L, and can be applied to fields such as medical monitors and new energy vehicle electronics. In addition, ceramic-based fixtures have a low coefficient of thermal expansion (2.0~4.2×10⁻). 6 ( / ℃) ensures stable positioning of the product within a wide temperature range of -40~125℃, further expanding the application possibilities in extreme environments.

[0111] Furthermore, the nanocomposite electroplating and ceramic-based fixture positioning are highly compatible with existing electronic component manufacturing production lines, allowing for upgrades without large-scale equipment modifications. Core processes such as laser stripping, electroplating, and reflow soldering can utilize existing equipment; upgrades can be achieved simply by optimizing parameters (e.g., segmented ultrasound in Example 1 and dual-pulse parameters in Example 2) and replacing customized components (e.g., ceramic-based fixtures and dedicated steel mesh), reducing enterprise technology upgrade costs. Simultaneously, the process parameters for each example can be flexibly adjusted (e.g., plating thickness, graphene content, fixture dimensions), allowing for rapid adaptation to different customers' inductor specifications and device types (capacitors, resistors, MOSFETs), resulting in fast batch production response. Moreover, the graphene dispersion, ceramic-based materials, and environmentally friendly plating solutions used in the process are all commercially mature materials with a stable supply chain, eliminating reliance on special consumables and ensuring large-scale promotion.

[0112] Other, such as Figure 2 As shown, the gray base block is a rectangular inductor block, and several white capacitor blocks are soldered onto the rectangular inductor block.

[0113] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A modular inductor, characterized in that, The device includes a carrier, which is a rectangular inductor. Electronic components are soldered onto the surface of the carrier, and the electronic components and the carrier form a module. The electronic components include, but are not limited to, capacitors, resistors, and MOSFETs.

2. The method for manufacturing a modular inductor as described in claim 1, characterized in that, Includes the following steps: Step 1: Inductor selection and preprocessing: Select a rectangular inductor as the carrier, and define the inductor's welding surface, bottom surface (parallel to the welding surface), long side surface (perpendicular to the welding surface and with a large area), and short side surface (perpendicular to the welding surface and with a small area). Step 2, Precise Paint Stripping: The inductor is placed in a customized laser paint stripping machine, and the paint is stripped only on the solder surface, short side surface and bottom surface, while the insulating paint layer on the long side surface is preserved. The paint stripping process uses pulsed laser mode with a laser wavelength of 355nm and a pulse width of 5~10ns. Depending on the material of the inductor body, various forms such as purple light, red light and green light can be selected to strip the paint layer of specific areas on the surface, avoiding overheating damage to the inductor substrate. Step 3, Multi-layer nanocomposite electroplating: The welded surface, short side and bottom surface after paint stripping are subjected to multi-layer nanocomposite electroplating treatment, which includes copper plating at the bottom layer, nickel-graphene nanocomposite plating in the middle layer and tin plating on the surface layer to form a conductive welded layer with high conductivity and high adhesion. In the nickel-graphene nanocomposite plating, the graphene is uniformly dispersed in the plating solution through ultrasonic dispersion process. Step 4, AOI Inspection: The flatness and parallelism of the coating are inspected using AOI equipment. There should be no obvious pits, bumps or coating defects, and the coplanarity test should meet the product usage requirements. Step 5, Fixing the ceramic-based fixture and printing solder paste: A special inductor solder paste printing and fixing fixture made of ceramic-based high-temperature resistant positioning material is used. The ceramic-based material is alumina-zirconia composite ceramic. The fixture uses a double fixing structure of vacuum adsorption and positioning pins to position and fix the bottom and short sides of the inductor respectively. Solder paste is printed on the fixed bottom and short sides using a customized stencil. If it is necessary to integrate devices on the electrode surface, a manual soldering station is reserved for the subsequent process. Step 6, SPI Inspection: The height, volume, and area of ​​the printed solder paste are inspected using SPI inspection equipment. The solder paste height deviation is ≤±5%, the volume deviation is ≤±10%, and the area coverage is ≥95% to ensure compliance with the soldering process requirements. Defective products are reprinted. Step 7, Component mounting: Electronic components are mounted onto the plated surface of the inductor. Several components are mounted on the short side and the bottom side respectively. The electronic components are capacitors, resistors and MOSFETs. The mounting process is assisted by a vision positioning system. Step 8, Reflow Soldering: Place the mounted inductors in a reflow oven and solder them according to the preset temperature profile. The temperature profile is as follows: preheating zone 60~120℃, constant temperature zone 120~150℃, reflow zone 210~260℃, cooling zone ≤80℃. Nitrogen gas is introduced for protection during the soldering process. The nitrogen purity is ≥99.99% and the oxygen content is ≤300ppm. Step 9, Finished Product Inspection: Conduct electrical performance and appearance inspections on the products using customized testing equipment. The on-resistance value is in the milliohm range, and the deviation of electronic component parameters is ≤±5%. Defective products are returned for repair or scrapped.

3. The method for manufacturing a modular inductor according to claim 2, characterized in that, The inductor materials are selected from FeNi alloy soft magnetic materials, FeSi alloy soft magnetic materials, FeSiAL alloy soft magnetic materials, amorphous soft magnetic materials, nanocrystalline soft magnetic materials, ferrite soft magnetic materials, etc. Among them, ferrite inductors have high permeability and low loss characteristics, making them suitable for low- and medium-frequency operating scenarios. Amorphous alloy inductors have better high-frequency response and temperature stability, which can meet the requirements of high-frequency circuit design. The inductors need to undergo an external cleaning process to remove surface oil, dust, and other impurities to avoid affecting the stability of subsequent paint stripping and electroplating processes.

4. The method for manufacturing a modular inductor according to claim 2, characterized in that, The total thickness of the multilayer nanocomposite electroplating is strictly controlled at 5~15μm, and the bottom copper plating layer is 3~8μm, utilizing the high conductivity of copper to reduce current transmission loss. The intermediate nickel-graphene nanocomposite coating is 1~4μm thick, which enhances the overall performance of the coating through the reinforcing effect of graphene; the surface tin coating is 1~3μm thick, which ensures good wetting and reliable connection during the welding process.

5. A method for manufacturing a modular inductor according to claim 2, characterized in that, The preparation steps of the plating solution for the nickel-graphene nanocomposite coating are as follows: Preparation of basic plating solution: Add nickel sulfate, nickel chloride and boric acid to deionized water in sequence, stir until completely dissolved, and control the concentration of nickel sulfate to 200~250g / L, the concentration of nickel chloride to 30~50g / L and the concentration of boric acid to 30~40g / L to form the basic plating solution; Preparation of graphene dispersion: Polyethylene glycol dispersant is added to deionized water, stirred and dissolved, and then graphene powder is added to prepare a graphene dispersion with a concentration of 0.1~0.5 g / L. Polyethylene glycol molecules are adsorbed on the surface of graphene sheets to form steric hindrance. Ultrasonic dispersion treatment: Place the graphene dispersion in an ultrasonic device with a power of 100~200W and disperse for 30~60 minutes to ensure that the thickness of the graphene sheets is ≤5nm and there is no obvious agglomeration. Mixing and volume adjustment: The ultrasonically dispersed graphene dispersion is slowly added to the base plating solution at a ratio of 5~15mL / L, and stirred continuously for 30min. Then, it is adjusted to the required volume with deionized water, allowed to stand for 10min, and then filtered to obtain the plating solution for preparing nickel-graphene nanocomposite coating.

6. The method for manufacturing a modular inductor according to claim 2, characterized in that, The positioning pins of the ceramic-based fixture are made of zirconia ceramic, and the preparation steps of the zirconia ceramic material are as follows: Raw material ratio: Take 94-97% zirconium oxide powder, 3-6% yttrium oxide powder and 0.5-1% alumina powder by weight percentage, mix them evenly, add anhydrous ethanol as dispersion medium, ball mill for 24-36 hours, ball-to-material ratio 10:1, and grind until the powder particle size is ≤1μm; Molding process: Spray dry the ball-milled slurry with an inlet air temperature of 180~200℃ and an outlet air temperature of 80~90℃ to obtain a free-flowing powder. Use cold isostatic pressing to form a blank for the positioning pin with a molding pressure of 150~200MPa and a holding pressure of 5~10min. Degreasing and sintering: Place the green blank in a degreasing furnace, heat it to 600~800℃ in an air atmosphere, hold it for 2~3 hours, and remove organic impurities; It is then transferred to a sintering furnace and held at 1550~1650℃ for 4~6 hours, then naturally cooled to room temperature to form a dense ceramic body; Precision machining: The ceramic blank is turned and ground using a diamond grinding wheel, with the diameter of the locating pin controlled at 1~2mm and the surface roughness Ra≤0.02μm; Performance optimization: The processed locating pins are ultrasonically cleaned at a power of 100~150W for 10~15min to remove surface impurities, and then dried at 200~300℃ for 1~2h to finally obtain zirconia ceramic locating pins with a hardness of HV≥1200 and a high temperature resistance of ≥300℃.

7. The method for manufacturing a modular inductor according to claim 2, characterized in that, The electronic component mounting process is assisted by a visual positioning system using a CCD camera and image recognition algorithm. The CCD camera captures the reference marks on the inductor plating surface and the image of the component mounting position. The image recognition algorithm performs coordinate calibration and deviation compensation. The positioning speed is ≤0.5s / piece, which meets the efficiency requirements of industrial mass production. The repeatability positioning accuracy is ≤±0.03mm, ensuring that the electronic components are accurately mounted in the solder paste printing area and avoiding defects such as misalignment and cold solder joints.

8. A method for manufacturing a modular inductor according to claim 2, characterized in that, The nickel-graphene nanocomposite coating achieves a performance leap through a nano-reinforcement mechanism, with a microhardness of ≥500HV, which is more than 40% higher than that of traditional pure nickel coating. It can effectively resist mechanical wear during mounting, welding and use, and has a salt spray corrosion resistance of ≥500h, making it suitable for humid and highly corrosive working environments.

9. A method for manufacturing a modular inductor according to claim 2, characterized in that, The activation treatment uses a 5-10% concentration of dilute sulfuric acid solution as the activator, and the soaking time is controlled at 1-2 minutes. The soaking temperature is maintained at 20-25℃ to avoid abnormal surface roughness caused by high temperature or long soaking. After the activation treatment, the surface is rinsed with deionized water 3-5 times to thoroughly remove residual acid and impurities, ensuring that the coating forms a strong metallurgical bond with the inductor substrate.

10. A method for manufacturing a modular inductor according to claim 2, characterized in that, The custom stencil is designed to match the inductor mounting. The mesh size is customized according to the shape and size of the electronic component pins to ensure that the solder paste printing amount matches the pin soldering requirements. The mesh wall thickness is set to 0.08~0.12mm, and the mesh edges are rounded with a radius of 0.01~0.02mm to avoid solder paste residue on the mesh edges during printing and reduce clogging.

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