Preparation method of microminiature anti-vibration high-reliability patch type common mode inductor

Abstract

The invention relates to the technical field of patch type common-mode inductors, and discloses a preparation method of a microminiature anti-vibration high-reliability patch type common-mode inductor, which comprises the following steps of: pretreating a magnetic core, selecting a magnetic material with high magnetic conductivity and low loss, preparing an I-shaped or E-shaped magnetic core by an injection molding or pressing process, and preparing the magnetic core; the method comprises the following steps of: cleaning the surface of a magnetic core, winding a coil winding, tightly and uniformly winding a high-strength and high-heat-resistance enameled wire on a winding post of the magnetic core according to a preset number of turns and a winding direction, and carrying out laser paint removal treatment; a laser paint removing technology is adopted to control the paint removing area and depth of the welding part of the enameled wire, it is guaranteed that a paint film is removed, a copper wire is not damaged, meanwhile, the uniform coating and reflow soldering technology of low-viscosity solder paste is matched, the problem of unreliable welding caused by a traditional paint removing mode can be effectively solved, and the welding quality is improved. And the conductivity and the long-term reliability of the inductor are further improved.

Description

Technical Field

[0001] This invention relates to the field of surface mount common mode inductor technology, specifically to a method for fabricating a miniature, vibration-resistant, and highly reliable surface mount common mode inductor. Background Technology

[0002] Surface mount common mode inductors are electromagnetic components designed specifically for surface mount technology. They are widely used in power line filtering, electromagnetic interference suppression, and radio frequency interference suppression, especially with the trend of miniaturization and high-density integration of electronic devices, their application range is becoming increasingly wider.

[0003] Currently, because the manufacturing process of surface mount common mode inductors involves multiple delicate steps, traditional processes use mechanical scraping or chemical stripping to treat the enameled wire welding area when welding and assembling the magnetic core and coil. This makes it impossible to precisely control the area and depth of enamel film removal. When enamel film residue or copper wire damage occurs, the welding reliability will decrease, and the stability of the electrical connection cannot be guaranteed.

[0004] Therefore, a method for fabricating a miniature, vibration-resistant, and highly reliable surface-mount common-mode inductor is proposed to address the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for fabricating a miniature, vibration-resistant, highly reliable surface-mount common-mode inductor, which solves the problems of decreased welding reliability and inability to guarantee the stability of electrical connections mentioned in the background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for fabricating a miniature, vibration-resistant, high-reliability surface-mount common-mode inductor, comprising the following steps:

[0007] Step 1: Core pretreatment. Select magnetic materials with high permeability and low loss, and make them into I-shaped or E-shaped magnetic cores through injection molding or pressing processes. Clean the surface of the magnetic core.

[0008] Step 2: Coil winding. High-strength, high-heat-resistant enameled wire is tightly and evenly wound on the winding post of the magnetic core according to the predetermined number of turns and winding direction.

[0009] Step 3: Assemble the wound magnetic core and the patch using epoxy resin glue to form a closed magnetic circuit, and place it in an oven to cure the glue.

[0010] Step 4: Laser paint stripping treatment. Using laser paint stripping technology, the power, frequency and scanning speed of the laser are precisely controlled to remove the paint from the welded parts of the coil winding.

[0011] Step 5: Apply low-viscosity solder paste. Select low-viscosity solder paste and apply it evenly to the terminals and areas of the coil winding where the paint has come off, using screen printing or dispensing.

[0012] Step 6: Reflow soldering. Place the magnetic core and coil winding assembly coated with low-viscosity solder paste into the reflow oven, set an appropriate reflow soldering temperature profile, so that the solder paste melts and fully wets the terminals and coil windings, and forms reliable solder joints after cooling.

[0013] Step 7: Testing and screening. The prepared surface mount common mode inductors are subjected to electrical performance testing and vibration resistance testing to screen out products that meet the quality requirements.

[0014] Preferably, the magnetic core in step one is made of manganese-zinc ferrite or nickel-zinc ferrite material, and the magnetic core size is (3-5) mm long × (2-4) mm wide × 3.5 mm high.

[0015] The pretreatment of the magnetic core includes the following steps: placing the prepared magnetic core in an ultrasonic cleaner and cleaning it with an organic solvent for 5-10 minutes; after cleaning, drying it in an oven at 80-100℃ for 30-60 minutes to remove surface impurities and moisture.

[0016] Preferably, the organic solvent is isopropanol or ethanol with a concentration of 95%-99%, and the power of the ultrasonic cleaner is set to 200-300W with a frequency of 40-60kHz.

[0017] Preferably, in step two, the coil winding uses polyesterimide or polyamideimide enameled wire with a wire diameter of 0.05-0.08 mm and 20-30 turns. During the winding process, the tension is kept uniform and controlled between 12-20 gf.

[0018] Preferably, the enameled wire has a coating thickness of 5-10 μm and a temperature resistance rating of 180-220℃. Before winding, the enameled wire is preheated at a temperature of 60-80℃ for 10-15 minutes.

[0019] Preferably, the laser paint stripping process in step four includes the following steps: first, calibrating the laser to ensure that the laser focus is accurately aligned with the welding area; controlling the paint stripping area to be a circle with a diameter of 1-2 mm or a rectangle of 2 mm × 1 mm; and ensuring that the paint stripping depth is just enough to remove the paint film without damaging the copper wire. The laser used is a pulsed fiber laser or an ultraviolet laser, with the laser power set to 4-5 W, the frequency to 15-20 kHz, and the scanning speed to 80-100 mm / s.

[0020] Preferably, the low-viscosity solder paste applied in step five is Sn99.3Cu0.7 solder paste or Sn96.5Ag3.0Cu0.5. The application of low-viscosity solder paste includes the following steps: first, the solder paste is warmed at 20-25℃ for 2-4 hours, then homogenized using a three-roll mill for 10-15 minutes at a speed of 100-200 r / min, and finally coated by screen printing or dispensing, with the solder paste thickness controlled at 0.1-0.15 mm.

[0021] Preferably, the temperature profile for reflow soldering in step six includes: a preheating zone temperature of 140-150℃ and a dwell time of 60-90 seconds; a constant temperature zone temperature of 170-180℃ and a dwell time of 90-120 seconds; a reflow zone temperature of 230-240℃ and a dwell time of 50-60 seconds; and a cooling zone cooling rate of 4-5℃ / second.

[0022] Preferably, the testing in step seven includes electrical performance testing and vibration resistance testing. Electrical performance testing includes inductance, impedance and insulation resistance testing. Vibration resistance testing is performed under the following conditions: vibration frequency of 10Hz-2000Hz-10Hz, amplitude of 1.5-3mm, cycle time of 20min, vibration direction of X, Y, Z, and vibration in each direction for 4 hours to test its performance stability.

[0023] Preferably, during vibration resistance testing, after the product operates in a vibration environment for 12 hours, the change rate of each parameter does not exceed 2%.

[0024] Compared with the prior art, the method for fabricating a miniature, vibration-resistant, high-reliability surface-mount common-mode inductor of the present invention has the following advantages:

[0025] 1. In this invention, when welding and assembling the magnetic core and coil winding, laser stripping technology is used to control the stripping area and depth of the enameled wire welding part, ensuring that the enamel film is removed without damaging the copper wire. At the same time, combined with the uniform coating of low-viscosity solder paste and reflow soldering process, the unreliable welding problem caused by traditional stripping methods can be effectively solved, ensuring the joint strength of the solder joint and the stability of the electrical connection, and further improving the conductivity and long-term reliability of the inductor.

[0026] 2. In this invention, during the coil winding process, the uniform tension winding technology and preheating process are adopted to ensure that the enameled wire is tightly and uniformly wound on the magnetic core. Combined with the symmetrical winding structure design, the inductance value deviation caused by loose and asymmetrical winding can be effectively avoided, the common mode suppression characteristics are enhanced, and the overall mechanical strength of the coil is improved, so that the inductor can maintain structural stability and consistent performance under vibration environment.

[0027] 3. In this invention, during the finished product testing stage, comprehensive electrical performance testing and vibration resistance testing are conducted, and the inductance, DC resistance, insulation resistance, and parameter stability under vibration environment are evaluated in all aspects. This effectively screens out products that do not meet the performance standards, reduces the problem of missed detection in traditional testing methods, and ensures that the final product has both high electrical performance and excellent mechanical reliability, meeting the stringent requirements of micro and small electronic devices for the vibration resistance and long-term stability of components. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1: A method for fabricating a miniature, vibration-resistant, high-reliability surface-mount common-mode inductor, comprising the following steps:

[0030] Step 1: Core pretreatment. Select magnetic materials with high permeability and low loss, and make them into I-shaped or E-shaped magnetic cores through injection molding or pressing processes. Clean the surface of the magnetic core.

[0031] Step 2: Coil winding. High-strength, high-heat-resistant enameled wire is tightly and evenly wound on the winding post of the magnetic core according to the predetermined number of turns and winding direction.

[0032] Step 3: Assemble the wound magnetic core and the patch using epoxy resin glue to form a closed magnetic circuit, and place it in an oven to cure the glue.

[0033] Step 4: Laser paint stripping treatment. Using laser paint stripping technology, the power, frequency and scanning speed of the laser are precisely controlled to remove the paint from the welded parts of the coil winding.

[0034] Step 5: Apply low-viscosity solder paste. Select low-viscosity solder paste and apply it evenly to the terminals and areas of the coil winding where the paint has come off, using screen printing or dispensing.

[0035] Step 6: Reflow soldering. Place the magnetic core and coil winding assembly coated with low-viscosity solder paste into the reflow oven, set an appropriate reflow soldering temperature profile, so that the solder paste melts and fully wets the terminals and coil windings, and forms reliable solder joints after cooling.

[0036] Step 7: Testing and screening. The prepared surface mount common mode inductors are subjected to electrical performance testing and vibration resistance testing to screen out products that meet the quality requirements.

[0037] The magnetic core in step one is made of manganese zinc ferrite or nickel zinc ferrite material. The core size is (3-5) mm long × (2-4) mm wide × 3.5 mm high, which conforms to the common size of 3225 / 4532.

[0038] The magnetic core pretreatment includes the following steps: placing the prepared magnetic core in an ultrasonic cleaner and cleaning it with an organic solvent for 5 minutes; after cleaning, drying it in an oven at 80°C for 30 minutes to remove surface impurities and moisture.

[0039] The organic solvent is isopropanol or ethanol, with a concentration of 95%, and the power of the ultrasonic cleaner is set to 200W and the frequency to 40kHz.

[0040] In step two, the coil winding uses polyesterimide or polyamideimide enameled wire with a wire diameter of 0.05mm and 20 turns. During the winding process, the tension is kept uniform and controlled between 12gf.

[0041] The enameled wire has a coating thickness of 5μm and a temperature resistance rating of 180℃. Before winding, the enameled wire is preheated at 60℃ for 10 minutes.

[0042] In step three, the oven is set to 150±5℃ for 90±5 minutes to cure the adhesive;

[0043] Step four of the laser paint removal process includes the following steps: First, calibrate the laser to ensure that the laser focus is accurately aligned with the welding area. The paint removal area is controlled to be a circle with a diameter of 1mm or a rectangle of 2mm×1mm. The paint removal depth is just enough to remove the paint film without damaging the copper wire. The laser used is a pulsed fiber laser or an ultraviolet laser. The laser power is set to 4W, the frequency is 15kHz, and the scanning speed is 80mm / s.

[0044] In step five, the low-viscosity solder paste is applied as Sn99.3Cu0.7 solder paste or Sn96.5Ag3.0Cu0.5. The application of low-viscosity solder paste includes the following steps: first, the solder paste is warmed at 20°C for 2 hours, then homogenized using a three-roll mill for 10 minutes at a speed of 100 r / min, and finally coated by screen printing or dispensing, with the solder paste thickness controlled at 0.1 mm.

[0045] The temperature profile for reflow soldering in step six includes: preheating zone temperature 140℃, dwell time 60 seconds, isothermal zone temperature 170℃, dwell time 90 seconds, reflow zone temperature 230℃, dwell time 50 seconds, and cooling zone cooling rate 4℃ / second.

[0046] The tests in step seven include electrical performance testing and vibration resistance testing. Electrical performance testing includes inductance, impedance and insulation resistance testing. Vibration resistance testing is conducted under the following conditions: vibration frequency cyclic 10Hz-2000Hz-10Hz, amplitude 1.5mm, each cycle time 20min, vibration direction X, Y, Z, and vibration in each direction for 4 hours to test its performance stability.

[0047] The standards for electrical performance testing are as follows: inductance tolerance is controlled within ±10%, impedance is not less than 1000Ω, DC resistance is not greater than 0.50Ω, insulation resistance is not less than 100MΩ, and during vibration performance testing, after the product has been working in a vibration environment for 12 hours, the change rate of each parameter does not exceed 2%.

[0048] Example 2: A method for fabricating a miniature, vibration-resistant, high-reliability surface-mount common-mode inductor, comprising the following steps:

[0049] Step 1: Core pretreatment. Select magnetic materials with high permeability and low loss, and make them into I-shaped or E-shaped magnetic cores through injection molding or pressing processes. Clean the surface of the magnetic core.

[0050] Step 2: Coil winding. High-strength, high-heat-resistant enameled wire is tightly and evenly wound on the winding post of the magnetic core according to the predetermined number of turns and winding direction.

[0051] Step 3: Assemble the wound magnetic core and the patch using epoxy resin glue to form a closed magnetic circuit, and place it in an oven to cure the glue.

[0052] Step 4: Laser paint stripping treatment. Using laser paint stripping technology, the power, frequency and scanning speed of the laser are precisely controlled to remove the paint from the welded parts of the coil winding.

[0053] Step 5: Apply low-viscosity solder paste. Select low-viscosity solder paste and apply it evenly to the terminals and areas of the coil winding where the paint has come off, using screen printing or dispensing.

[0054] Step 6: Reflow soldering. Place the magnetic core and coil winding assembly coated with low-viscosity solder paste into the reflow oven, set an appropriate reflow soldering temperature profile, so that the solder paste melts and fully wets the terminals and coil windings, and forms reliable solder joints after cooling.

[0055] Step 7: Testing and screening. The prepared surface mount common mode inductors are subjected to electrical performance testing and vibration resistance testing to screen out products that meet the quality requirements.

[0056] The magnetic core in step one is made of manganese zinc ferrite or nickel zinc ferrite material. The core size is (3-5) mm long × (2-4) mm wide × 3.5 mm high, which conforms to the common size of 3225 / 4532.

[0057] The magnetic core pretreatment includes the following steps: placing the prepared magnetic core in an ultrasonic cleaner and cleaning it with an organic solvent for 7 minutes; after cleaning, drying it in a 90°C oven for 50 minutes to remove surface impurities and moisture.

[0058] The organic solvent is isopropanol or ethanol, with a concentration of 97%, and the power of the ultrasonic cleaner is set to 250W and the frequency to 50kHz.

[0059] In step two, the coil winding uses polyesterimide or polyamideimide enameled wire with a wire diameter of 0.06mm and 25 turns. During the winding process, the tension is kept uniform and controlled between 16gf.

[0060] The enameled wire has a coating thickness of 8μm and a temperature resistance rating of 190℃. Before winding, the enameled wire is preheated at 70℃ for 12 minutes.

[0061] In step three, the oven is set to 150±5℃ for 90±5 minutes to cure the adhesive;

[0062] Step four of the laser paint removal process includes the following steps: First, calibrate the laser to ensure that the laser focus is accurately aligned with the welding area. The paint removal area is controlled to be a circle with a diameter of 1.5mm or a rectangle of 2mm×1mm. The paint removal depth is just enough to remove the paint film without damaging the copper wire. The laser used is a pulsed fiber laser or an ultraviolet laser. The laser power is set to 4.5W, the frequency is 18kHz, and the scanning speed is 90mm / s.

[0063] In step five, the low-viscosity solder paste is applied as Sn99.3Cu0.7 solder paste or Sn96.5Ag3.0Cu0.5. The application of low-viscosity solder paste includes the following steps: first, the solder paste is warmed at 23°C for 3 hours, then homogenized using a three-roll mill for 12 minutes at a speed of 150 r / min, and finally coated by screen printing or dispensing, with the solder paste thickness controlled at 0.13 mm.

[0064] The temperature profile for reflow soldering in step six includes: preheating zone temperature 145℃, dwell time 60-90 seconds, isothermal zone temperature 175℃, dwell time 105 seconds, reflow zone temperature 235℃, dwell time 55 seconds, and cooling zone cooling rate 4.5℃ / second.

[0065] The tests in step seven include electrical performance testing and vibration resistance testing. Electrical performance testing includes inductance, impedance and insulation resistance testing. Vibration resistance testing is conducted under the following conditions: vibration frequency of 10Hz-2000Hz-10Hz cycle, amplitude of 2mm, each cycle time of 20min, vibration direction of X, Y, Z, and vibration in each direction for 4 hours to test its performance stability.

[0066] The standards for electrical performance testing are as follows: inductance tolerance is controlled within ±10%, impedance is not less than 1000Ω, DC resistance is not greater than 0.5Ω, insulation resistance is not less than 100MΩ, and during vibration performance testing, after the product has been working in a vibration environment for 12 hours, the change rate of each parameter does not exceed 2%.

[0067] Example 3: A method for fabricating a miniature, vibration-resistant, high-reliability surface-mount common-mode inductor, comprising the following steps:

[0068] Step 1: Core pretreatment. Select magnetic materials with high permeability and low loss, and make them into I-shaped or E-shaped magnetic cores through injection molding or pressing processes. Clean the surface of the magnetic core.

[0069] Step 2: Coil winding. High-strength, high-heat-resistant enameled wire is tightly and evenly wound on the winding post of the magnetic core according to the predetermined number of turns and winding direction.

[0070] Step 3: Assemble the wound magnetic core and the patch using epoxy resin glue to form a closed magnetic circuit, and place it in an oven to cure the glue.

[0071] Step 4: Laser paint stripping treatment. Using laser paint stripping technology, the power, frequency and scanning speed of the laser are precisely controlled to remove the paint from the welded parts of the coil winding.

[0072] Step 5: Apply low-viscosity solder paste. Select low-viscosity solder paste and apply it evenly to the terminals and areas of the coil winding where the paint has come off, using screen printing or dispensing.

[0073] Step 6: Reflow soldering. Place the magnetic core and coil winding assembly coated with low-viscosity solder paste into the reflow oven, set an appropriate reflow soldering temperature profile, so that the solder paste melts and fully wets the terminals and coil windings, and forms reliable solder joints after cooling.

[0074] Step 7: Testing and screening. The prepared surface mount common mode inductors are subjected to electrical performance testing and vibration resistance testing to screen out products that meet the quality requirements.

[0075] The magnetic core in step one is made of manganese zinc ferrite or nickel zinc ferrite material. The core size is (3-5) mm long × (2-4) mm wide × 3.5 mm high, which conforms to the common size of 3225 / 4532.

[0076] The magnetic core pretreatment includes the following steps: placing the prepared magnetic core in an ultrasonic cleaner and cleaning it with an organic solvent for 10 minutes; after cleaning, drying it in an oven at 100°C for 60 minutes to remove surface impurities and moisture.

[0077] The organic solvent is isopropanol or ethanol, with a concentration of 99%, and the power of the ultrasonic cleaner is set to 300W and the frequency to 60kHz.

[0078] In step two, the coil winding uses polyesterimide or polyamideimide enameled wire with a wire diameter of 0.08mm and 30 turns. During the winding process, the tension is kept uniform and controlled between 20gf.

[0079] The enameled wire has a coating thickness of 10μm and a temperature resistance rating of 220℃. Before winding, the enameled wire is preheated at 80℃ for 15 minutes.

[0080] In step three, the oven is set to 150±5℃ for 90±5 minutes to cure the adhesive;

[0081] Step four of the laser paint removal process includes the following steps: First, calibrate the laser to ensure that the laser focus is accurately aligned with the welding area. The paint removal area is controlled to be a circle with a diameter of 2mm or a rectangle of 2mm×1mm. The paint removal depth is just enough to remove the paint film without damaging the copper wire. The laser used is a pulsed fiber laser or an ultraviolet laser. The laser power is set to 5W, the frequency is 20kHz, and the scanning speed is 100mm / s.

[0082] In step five, the low-viscosity solder paste is applied as Sn99.3Cu0.7 solder paste or Sn96.5Ag3.0Cu0.5. The application of low-viscosity solder paste includes the following steps: first, the solder paste is warmed at 25°C for 4 hours, then homogenized using a three-roll mill for 15 minutes at a speed of 200 r / min, and finally coated by screen printing or dispensing, with the solder paste thickness controlled at 0.15 mm.

[0083] The temperature profile for reflow soldering in step six includes: preheating zone temperature 150℃, dwell time 90 seconds, isothermal zone temperature 180℃, dwell time 120 seconds, reflow zone temperature 240℃, dwell time 60 seconds, and cooling zone cooling rate 5℃ / second.

[0084] The tests in step seven include electrical performance testing and vibration resistance testing. Electrical performance testing includes inductance, impedance and insulation resistance testing. Vibration resistance testing is conducted under the following conditions: vibration frequency of 10Hz-2000Hz-10Hz cycle, amplitude of 13mm, each cycle time of 20min, vibration direction of X, Y, Z, and vibration in each direction for 4 hours to test its performance stability.

[0085] The standards for electrical performance testing are as follows: inductance tolerance is controlled within ±10%, impedance is not less than 1000Ω, DC resistance is not greater than 0.50Ω, insulation resistance is not less than 100MΩ, and during vibration performance testing, after the product has been working in a vibration environment for 12 hours, the change rate of each parameter does not exceed 2%.

[0086] Comparative Example 1: The difference between this comparative example and Example 1 is that this comparative example uses a mechanical scraping method to remove the enamel coating from the coil winding during welding.

[0087] Comparative Example 2 differs from Example 2 in that it uses high-viscosity silver-containing solder paste for soldering.

[0088] Comparative Example 3 differs from Example 3 in that the enameled wire was not preheated in this comparative example.

[0089] Comparative Example 4 differs from Example 3 in that the vibration resistance performance of this comparative example was not tested after reflow soldering.

[0090] The performance of the miniature vibration-resistant, high-reliability surface-mount common-mode inductors prepared in Examples 1-3 and Comparative Examples 1-4 was tested. The test items and methods are as follows:

[0091] Inductance was measured using an LCR digital bridge at a frequency of 100kHz and a test voltage of 0.5V.

[0092] DC resistance testing was performed using the four-terminal method, with a micro-ohmmeter used to measure the resistance value under a DC current of 100mA.

[0093] Insulation resistance test: Under an environment of 100V DC voltage and 60 seconds test time, use an insulation resistance tester to measure the resistance value between the pin and the magnetic core.

[0094] For vibration resistance testing, the sample was fixed on a vibration table and vibrated for 1 hour at a frequency of 10Hz-2000Hz-10Hz and an amplitude of 1.5mm. The change rate of inductance was then measured again.

[0095] The test data of the surface-mount common-mode inductors prepared in Examples 1-3 and Comparative Examples 1-4 are recorded in the table below:

[0096] By comparing and analyzing the data in the table, it can be seen that the miniature, vibration-resistant, high-reliability surface-mount common-mode inductors prepared using the processes in Examples 1-3 exhibit significantly superior performance compared to the products prepared using the processes in Comparative Examples 1-4. This indicates that during the welding and assembly of the magnetic core and coil windings, using laser stripping technology to control the stripping area and depth of the enameled wire welding area ensures the removal of the enamel film without damaging the copper conductors. Simultaneously, combined with the uniform application of low-viscosity solder paste and reflow soldering processes, this effectively solves the unreliability problem caused by traditional stripping methods, ensuring the solder joint strength and electrical connection stability, further improving the inductor's conductivity and long-term reliability. During the coil winding process, the use of uniform tension winding technology and preheating treatment... The process ensures that the enameled wire is tightly and evenly wound on the magnetic core. Combined with a symmetrical winding structure design, this effectively avoids inductance deviations caused by loose or asymmetrical windings, enhances common-mode rejection characteristics, and improves the overall mechanical strength of the coil. This allows the inductor to maintain structural stability and consistent performance even under vibration. During the finished product testing stage, comprehensive electrical performance testing and vibration resistance testing are conducted. At the same time, a full-scale evaluation of inductance, DC resistance, insulation resistance, and parameter stability under vibration conditions is performed. This effectively filters out substandard products, reduces the problem of missed detection in traditional testing methods, and ensures that the final product has both high electrical performance and excellent mechanical reliability, meeting the stringent requirements of micro-miniature electronic devices for component vibration resistance and long-term stability.

[0097] By comparing and analyzing the relevant data in the table, it can be seen that the miniature surface-mount common-mode inductor produced by the process of this invention not only has excellent electrical performance, but also exhibits vibration resistance reliability and long-term stability. This indicates that the miniature vibration-resistant and highly reliable surface-mount common-mode inductor manufacturing process provided by this invention has a broader market prospect and is more suitable for promotion.

[0098] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0099] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for manufacturing a micro-sized anti-vibration high-reliability chip-type common-mode inductor, characterized in that, The method comprises the following steps: Step one: magnetic core pretreatment, select high magnetic permeability, low loss of magnetic material, by injection molding or pressing process to make I-shaped or E-shaped magnetic core, and clean the surface of the magnetic core; Step two: winding winding, high strength, high heat resistance of the enameled wire according to the predetermined number of turns and winding direction tightly and uniformly wound on the winding column of the magnetic core; Step three: the wound magnetic core is assembled with the patch using epoxy resin glue, forming a closed magnetic circuit, and placed in an oven for glue curing; Step four: laser paint removal treatment, using laser paint removal technology, accurate control of laser power, frequency and scanning speed, the soldering part of the coil winding is treated by paint removal; Step five: coating low viscosity solder paste, select low viscosity solder paste, by screen printing or dispensing method, evenly coated on the terminal and the coil winding paint removal part; Step six: reflow soldering, the magnetic core and coil winding assembly coated with low viscosity solder paste is put into the reflow soldering furnace, set the appropriate reflow soldering temperature curve, make the solder paste melt and fully wet the terminal and coil winding, after cooling, form reliable welding point; Step seven: detection and screening, the prepared patch type common mode inductor is detected for electrical performance and anti-vibration performance, and the products meeting the quality requirements are screened out.

2. The method for fabricating a miniature, vibration-resistant, high-reliability surface-mount common-mode inductor according to claim 1, characterized in that: The magnetic core in step one is made of manganese zinc ferrite or nickel zinc ferrite material, and the size of the magnetic core is (3-5) mm in length, (2-4) mm in width and 3.5 mm max in height; The magnetic core pretreatment comprises the following steps: the prepared magnetic core is placed in an ultrasonic cleaner, cleaned with organic solvent, the cleaning time is 5-10 minutes, and after cleaning, the magnetic core is dried in an oven at 80-100 DEG C for 30-60 minutes to remove surface impurities and moisture.

3. The method of claim 2, wherein the method further comprises: forming a first magnetic core and a second magnetic core; and forming a first magnetic core and a second magnetic core. The organic solvent is isopropyl alcohol or ethanol, the concentration is 95%-99%, the power of the ultrasonic cleaner is set to 200-300 W, and the frequency is 40-60 kHz.

4. The method for fabricating a miniature, vibration-resistant, high-reliability surface-mount common-mode inductor according to claim 1, characterized in that, The coil winding in step two adopts polyester imine or polyamide imide enameled wire, the wire diameter is 0.05-0.08 mm, the winding turns are 20-30 turns, and the tension is kept uniform during winding, the tension control is between 12-20 gf.

5. The method of claim 1, wherein the method further comprises: forming a plurality of magnetic cores in the magnetic core layer; and forming a plurality of magnetic shields in the magnetic shield layer. The film thickness of the enameled wire is 5-10 μm, the temperature resistance grade is 180-220 DEG C, and the enameled wire is preheated before winding, the preheating temperature is 60-80 DEG C, and the time is 10-15 minutes.

6. The method of claim 1, wherein the method further comprises: The laser paint removal treatment in step four comprises the following steps: first, calibrate the laser, make sure the laser focal point is accurately aligned with the soldering part, the paint removal area is controlled to be a circle with a diameter of 1-2 mm or a rectangle of 2 mm*1 mm, the paint removal depth is just enough to remove the film but not to damage the copper wire, the laser used is pulse fiber laser or ultraviolet laser, the laser power is set to 4-5 W, the frequency is 15-20 kHz, and the scanning speed is 80-100 mm / s.

7. The method of claim 1, wherein the method further comprises: forming a plurality of magnetic cores in the magnetic core layer; and forming a plurality of magnetic shields in the magnetic shield layer. The low-viscosity tin paste coated in the fifth step is Sn99.3Cu0.7 tin paste or Sn96.5Ag3.0Cu0.5, and the coating of the low-viscosity tin paste comprises the following steps: firstly, the tin paste is warmed at 20-25℃ for 2-4 hours, then homogenized by a three-roll mill for 10-15 minutes at a speed of 100-200r / min, and finally coated by screen printing or dispensing, with the thickness of the tin paste controlled at 0.1-0.15mm.

8. The method of claim 1, wherein the method further comprises: forming a plurality of magnetic cores in the magnetic core layer; and forming a plurality of magnetic shields in the magnetic shield layer. The temperature curve of the reflow soldering in the sixth step comprises the following steps: preheating at 140-150℃ for 60-90 seconds, constant temperature at 170-180℃ for 90-120 seconds, reflow at 230-240℃ for 50-60 seconds, and cooling at a rate of 4-5℃ / s.

9. The method for fabricating a miniature, vibration-resistant, high-reliability surface-mount common-mode inductor according to claim 1, characterized in that, The detection in the seventh step comprises electrical performance detection and anti-vibration performance detection, the electrical performance detection comprises inductance, impedance and insulation resistance tests, and the anti-vibration performance detection tests the performance stability under the conditions that the vibration frequency is 10Hz-2000Hz-10Hz cycle, the amplitude is 1.5-3mm, each cycle time is 20min, and the vibration direction is X, Y and Z, with each direction vibrating for 4 hours.

10. The method of claim 1, wherein the method comprises: In the anti-vibration performance detection, the change rate of each parameter does not exceed 2% after the product works in the vibration environment for 12 hours.

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