Cooling fan packaging process

Abstract

The invention discloses a cooling fan packaging technology, and relates to the technical field of fan production, and the technology comprises the steps: precisely placing a cooling fan motor at a preset position of a circuit board; the method comprises the following steps: firstly, carrying out first-time epoxy resin potting at the thickness of 1-3mm, wherein the epoxy resin needs to be preheated for 30 minutes to 1 hour at 40-60 DEG C; and after the single crystal silicon glue is cured, the single crystal silicon glue is subjected to secondary potting with the thickness of 0.5-2 mm, the single crystal silicon glue needs to be subjected to defoaming treatment, and a segmented potting mode is adopted. The process further comprises the steps of circuit board cleaning before potting, performance testing after potting and appearance inspection. Experiments show that by means of the process, the core temperature of the cooling fan is reduced by 8.1 DEG C within 2 hours, the qualified rate of a water immersion test is increased by 36.7%, the insulation resistance is increased to 2.27 times that of a traditional process, the cooling effect, the waterproof performance and the electrical stability are remarkably improved, and the requirement for high reliability of precision equipment is met.

Description

Technical Field

[0001] This invention relates to the field of fan manufacturing technology, and in particular to a heat dissipation fan packaging process. Background Technology

[0002] In the field of cooling fan manufacturing, the packaging process directly affects the product's heat dissipation efficiency, stability, and lifespan. Traditional cooling fan packaging often uses a single-step epoxy resin potting process, which has several technical drawbacks: First, the potting material is not pretreated, and the high viscosity of the epoxy resin leads to poor flowability, making it easy to generate bubbles and voids during the potting process, affecting the integrity of the heat dissipation path; second, single-layer thick potting is prone to internal stress due to curing shrinkage, causing component displacement or circuit damage, resulting in unstable electrical performance; third, incomplete cleaning of the circuit board leads to poor bonding between the potting material and the substrate, forming gaps and channels, resulting in weak waterproof performance and a tendency for short circuits in humid environments.

[0003] Meanwhile, traditional processes rely on manual motor positioning, which, due to insufficient precision, leads to assembly deviations and further exacerbates uneven heat dissipation and speed fluctuations. These shortcomings result in high failure rates and rapid degradation of heat dissipation efficiency for conventionally packaged cooling fans in high-temperature and high-humidity environments, making it difficult to meet the high reliability requirements of precision electronic equipment. Therefore, there is an urgent need to optimize the packaging process to improve the overall performance of cooling fans. Summary of the Invention

[0004] To address the technical problems existing in the background art, this invention proposes a heat dissipation fan packaging process.

[0005] The present invention proposes a heat dissipation fan packaging process, comprising:

[0006] The motor portion of the cooling fan is precisely placed at a predetermined position on the circuit board;

[0007] The first potting is performed using epoxy resin, with the potting thickness controlled between 1 mm and 3 mm.

[0008] After the epoxy resin has fully cured, a second potting process is performed using monocrystalline silicone, with a potting thickness of 0.5 mm to 2 mm.

[0009] Furthermore, in the epoxy resin potting step, the potting thickness of the epoxy resin is 1.5 mm to 2.5 mm.

[0010] Furthermore, in the monocrystalline silicone potting step, the potting thickness of the monocrystalline silicone is 0.8 mm to 1.5 mm.

[0011] Furthermore, the epoxy resin needs to be preheated before use, with the preheating temperature controlled between 40°C and 60°C and the preheating time between 30 minutes and 1 hour, in order to reduce the viscosity of the epoxy resin and improve its fluidity and potting effect; at the same time, the monocrystalline silicone also needs to be degassed before use to eliminate air bubbles and ensure potting quality.

[0012] Furthermore, during the potting process, a segmented potting method should be adopted, that is, the core area of ​​the motor part should be potted first, and after it has initially cured, the outer area should be potted. This is to avoid the internal stress caused by the volume shrinkage of the potting material during the curing process from adversely affecting the electronic components. At the same time, segmented potting also helps to improve the filling rate and density of the potting material.

[0013] Furthermore, the process also includes a thorough cleaning of the circuit board before potting, using professional cleaning agents and tools to remove oil, dust and other impurities from the circuit board surface to ensure good adhesion and conductivity between the potting material and the circuit board.

[0014] Furthermore, the process also includes conducting comprehensive performance tests on the cooling fan after potting, including heat dissipation performance tests, waterproof performance tests, and electrical performance tests, to ensure that all performance indicators of the cooling fan meet the design requirements and have stable and reliable working capabilities.

[0015] Furthermore, in the single-crystal silicone potting step, the curing time of the single-crystal silicone must be strictly controlled within the range of 12 to 24 hours to ensure that it is fully cured and achieves the best physical and chemical properties, while avoiding adverse effects on electronic components caused by excessively long or short curing times.

[0016] Furthermore, the process also includes a detailed visual inspection of the cooling fan after the potting material has cured, using professional testing tools and methods to check for bubbles and cracks on the surface of the cooling fan, in order to ensure the appearance quality and aesthetics of the product.

[0017] Furthermore, the process also includes conducting a rigorous waterproof performance test on the cooling fan after the potting material has cured. The cooling fan is placed in a simulated underwater or humid environment to observe whether it can work normally and maintain stable performance, so as to ensure the reliability and durability of the product in actual applications.

[0018] The beneficial effects of this invention are as follows:

[0019] In terms of heat dissipation, a composite structure of epoxy resin and monocrystalline silicone double-encapsulation is adopted, combined with epoxy resin preheating treatment (50℃ / 45 minutes), which effectively reduces the material viscosity and optimizes the heat conduction path. Experimental data shows that the core temperature of the motor in the experimental group was only 35.1℃ after 2 hours, which is 8.1℃ lower than the control group of the traditional process (43.2℃), and the average heat dissipation rate was increased by 25.3%. This can more efficiently remove the heat generated by the operation of electronic components and avoid performance degradation caused by high temperature.

[0020] Waterproof performance has been significantly enhanced through professional circuit board cleaning (anhydrous ethanol treatment), vacuum degassing of single-crystal silicone, and segmented potting processes, which significantly improves the sealing performance of the encapsulation layer. In the water immersion test, the pass rate of the experimental group reached 96.7%, an increase of 36.7% compared to the control group (60.0%); the pass rate in the high humidity environment test reached 100%, an increase of 30.0% compared to the control group (70.0%), ensuring that the fan can still work stably in humid or water-immersed environments and greatly reducing the risk of short circuit failure.

[0021] The device boasts superior electrical performance and enhanced stability. A specialized fixture precisely positions the motor, reducing assembly deviations, while a segmented potting process minimizes the impact of curing stress on the component. The experimental group's full-load current decreased to 0.85A, a 7.6% reduction compared to the control group (0.92A), resulting in lower energy consumption. Insulation resistance increased to 500MΩ, 2.27 times that of the control group (220MΩ), significantly improving electrical safety. Speed ​​fluctuation was only 15rpm, a 64.3% reduction compared to the control group (42rpm), greatly enhancing operational stability and extending the fan's lifespan. Detailed Implementation

[0022] This invention proposes a cooling fan packaging process that, through a series of precise and rigorous step controls and material processing, ensures that the cooling fan maintains a stable and reliable operating state even in complex environments. The following is a detailed description of the specific implementation of this process:

[0023] In the preparation stage, the circuit board must first be thoroughly cleaned. Anhydrous ethanol is chosen as the cleaning agent because of its good solubility and volatility, effectively removing oil, dust, and other impurities from the circuit board surface. Use a soft cloth dampened with an appropriate amount of anhydrous ethanol to gently wipe the circuit board surface, being careful not to apply excessive force to avoid damaging the components and circuitry. After cleaning, place the circuit board in a well-ventilated area to air dry naturally, or use dry compressed air to blow-dry it, ensuring that no cleaning agent or moisture residue remains on the surface.

[0024] At the same time, prepare the motor part of the cooling fan and other necessary potting materials and tools, such as epoxy resin, monocrystalline silicone, potting equipment, thermometer, timer, etc., and check that these materials and tools are in good condition to ensure the smooth progress of subsequent processes.

[0025] Next, precisely place the motor portion of the cooling fan into its designated position on the cleaned and dried circuit board. This step requires high precision and can be assisted by using specialized positioning tools or clamps to ensure proper alignment and secure fixation between the motor and the circuit board. During placement, take care to avoid collisions between the motor and other components to prevent damage or displacement.

[0026] For the first potting, epoxy resin is used as the potting material. Before potting, the epoxy resin is preheated. The epoxy resin is placed in a constant temperature chamber, and the preheating temperature is precisely controlled at approximately 50°C for 45 minutes. During preheating, the epoxy resin should be stirred regularly to ensure even heating, reduce viscosity, and improve flowability and potting effect.

[0027] During potting, preheated epoxy resin is evenly poured around the motor section using potting equipment. The potting thickness should be strictly controlled to approximately 2 mm. This can be achieved by setting a precise potting volume on the potting equipment or by using a thickness measuring tool for real-time monitoring. Ensuring the motor section is fully and evenly covered is crucial for securing the motor, enhancing heat dissipation, and providing some waterproofing.

[0028] During the potting process, it is important to observe the flow of the epoxy resin to avoid defects such as air bubbles and voids. If air bubbles are found, they can be gently punctured with a syringe or similar tool to release the gas and ensure potting quality.

[0029] After the epoxy resin potting is complete, place it in a suitable, well-ventilated environment for natural curing. The curing time depends on the type of epoxy resin and the ambient temperature, but generally takes about 24 hours. During the curing process, avoid external factors that may interfere with the potted part, such as vibration and dust, to ensure that the epoxy resin can fully cure and achieve the expected fixing and protective effects.

[0030] After the epoxy resin has fully cured, a second potting process is performed using monocrystalline silicone as the potting material. Before potting, the monocrystalline silicone undergoes a degassing treatment. The monocrystalline silicone is placed in a vacuum degassing machine and degassed under a certain vacuum. The degassing time depends on the amount and viscosity of the monocrystalline silicone, but generally takes about 30 minutes to eliminate air bubbles and ensure potting quality.

[0031] During potting, the degassed monocrystalline silicone is uniformly poured onto the surface and surrounding area of ​​the cured epoxy resin using potting equipment. The potting thickness of the monocrystalline silicone is precisely controlled at approximately 1.2 mm, employing a segmented potting method. The core area of ​​the motor is potted first, and after initial curing (generally requiring about 6 hours), the outer areas are then potted. Segmented potting avoids the adverse effects on electronic components caused by internal stress due to volume shrinkage of the potting material during curing, while also helping to improve the filling rate and density of the potting material.

[0032] During the potting process, the amount of monocrystalline silicone used and the potting speed must be strictly controlled to ensure uniform potting thickness. Professional measuring tools can be used to measure and adjust the potting thickness in real time.

[0033] After the monocrystalline silicone is potted, it should be placed in an environment with suitable temperature and humidity for curing. The curing time of the monocrystalline silicone should be strictly controlled to around 18 hours, and the curing temperature should be maintained at around 25℃. Too short a curing time may result in incomplete curing of the monocrystalline silicone, affecting its protective effect; too long a curing time may have adverse effects on electronic components, such as causing component aging.

[0034] During the curing process, the curing status of the monocrystalline silicone should be checked regularly, observing whether its surface is smooth and free of defects such as cracks. If any abnormalities are found, measures should be taken promptly to address them.

[0035] After the potting material has fully cured, a comprehensive performance test is conducted on the cooling fan.

[0036] The first step is heat dissipation performance testing. The cooling fan is installed on specialized testing equipment to simulate actual working conditions. Its heat dissipation performance is evaluated by measuring parameters such as temperature change, airflow, and air pressure over a specific time period. Infrared thermal imagers and other equipment can be used to monitor the surface temperature distribution of the cooling fan to ensure that its heat dissipation effect meets design requirements.

[0037] Secondly, a waterproof performance test is conducted. The cooling fan is placed in a simulated underwater or humid environment, such as immersing it in water for a certain period of time (generally 30 minutes) or placing it in a high-humidity environment (humidity exceeding 90%), to observe whether it can function normally and maintain stable performance. During the test, the electrical parameters and operating status of the cooling fan should be closely monitored, and any abnormalities should be recorded and analyzed promptly.

[0038] Finally, electrical performance testing is conducted using professional electrical testing equipment, such as multimeters and oscilloscopes, to measure the electrical parameters of the cooling fan, including voltage, current, power, and insulation resistance, to check whether it meets the design requirements. Simultaneously, the cooling fan's starting performance and speed stability are tested to ensure its electrical performance is good.

[0039] Perform a thorough visual inspection on the cooling fans that have completed performance testing. Using professional testing tools and methods, such as magnifying glasses and microscopes, carefully examine the surface of the cooling fans for bubbles, cracks, scratches, or other defects. Simultaneously, check whether the dimensions of the cooling fans meet design requirements and whether the assembly of all components is secure and neat.

[0040] Performance testing experiment

[0041] I. Experimental Objective

[0042] The aim is to verify the advantages of the heat dissipation, waterproof performance and electrical performance of the cooling fan made based on the innovative packaging process (double potting, material pretreatment, segmented potting, etc.). By comparing it with the control group of traditional packaging process, the technical value of the innovative process is quantitatively evaluated.

[0043] II. Experimental Samples

[0044] 1) Experimental group samples

[0045] Thirty cooling fans were manufactured using the cooling fan packaging process proposed in this invention. The key process parameters are as follows:

[0046] Circuit board cleaning: Wipe with anhydrous ethanol and air dry.

[0047] Motor positioning: Precisely fixed with a special clamp.

[0048] First potting: Preheat epoxy resin to 50℃ (45 minutes), potting thickness 2mm, and allow to cure naturally for 24 hours.

[0049] Second potting: Vacuum degassing of monocrystalline silicone (30 minutes), potting thickness 1.2mm, segmented potting (the core area is initially cured for 6 hours before the outer perimeter is potted), curing time 18 hours (25℃).

[0050] 2) Control group samples

[0051] Thirty cooling fans were manufactured using a traditional single-step potting process. The process parameters are as follows:

[0052] Circuit board cleaning: No professional cleaning was performed (only compressed air blowing).

[0053] Motor positioning: manual visual positioning.

[0054] Encapsulation: Single epoxy resin encapsulation (without preheating), 3mm thickness, unsegmented encapsulation, curing time 24 hours (natural curing).

[0055] III. Test Items and Methods

[0056] 1) Heat dissipation performance test

[0057] Test environment: 25℃ ambient temperature, windless environment, cooling fan installed in standard heat dissipation test fixture (simulating computer CPU heat dissipation scenario).

[0058] Test method: The fan runs at full load for 2 hours. The temperature of the core area of ​​the motor is monitored in real time using an infrared thermal imager (accuracy ±0.5℃). The initial temperature (t=0), the temperature at 1 hour (t=1h), and the temperature at 2 hours (t=2h) are recorded. The average heat dissipation rate (temperature drop value / time) over 2 hours is calculated.

[0059] 2) Waterproof performance test

[0060] Water immersion test: Immerse the fan completely in 10cm deep room temperature water (25℃) for 30 minutes, remove it and let it dry for 30 minutes before powering it on and running it to check for short circuits (use a multimeter to measure insulation resistance) and whether the speed is stable (tachometer accuracy ±10rpm).

[0061] High humidity test: Place the fan in a constant temperature and humidity chamber (90% humidity, 30℃) for 48 hours, remove it and immediately power it on to test its operating status and insulation resistance (standard ≥100MΩ).

[0062] 3) Electrical performance testing

[0063] Full-load current test: The fan is operated at full load under rated voltage (12V), and the current value during stable operation is recorded using a digital multimeter (accuracy ±0.01A).

[0064] Insulation resistance test: The insulation resistance between the motor and the circuit board is tested using an insulation resistance tester (500V range).

[0065] Speed ​​stability test: The fan runs at full load for 2 hours, and the speed is recorded every 10 minutes (tachometer) and the speed fluctuation value (maximum value - minimum value) is calculated.

[0066] IV. Test Data Statistics

[0067] 1) Heat dissipation performance test data (unit: ℃)

[0068]

[0069]

[0070] 2) Waterproof performance test data

[0071]

[0072] 3) Electrical performance test data

[0073]

[0074] V. Experimental Conclusions

[0075] Heat dissipation effect: The core temperature of the experimental group (35.1℃) after 2 hours was significantly lower than that of the control group (43.2℃), and the average heat dissipation rate was increased by 25.3%, indicating that the two potting processes (epoxy resin to enhance heat dissipation + single crystal silicone to optimize heat conduction) and material preheating treatment effectively improved the heat dissipation performance.

[0076] Waterproof performance: The pass rate of the immersion test (96.7%) and the pass rate of the high humidity test (100%) of the experimental group were significantly higher than those of the control group, indicating that the segmented potting, degassing of monocrystalline silicone and pre-pouring cleaning process significantly improved the sealing and waterproofing capabilities.

[0077] Electrical performance: The experimental group had lower full-load current (lower energy consumption), higher insulation resistance (better safety), and smaller speed fluctuations (stronger operational stability), which confirms the optimizing effect of precise positioning and segmented potting to reduce internal stress on electrical performance.

[0078] 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 heat dissipation fan packaging process, characterized in that, include: The motor portion of the cooling fan is precisely placed at a predetermined position on the circuit board; The first potting is performed using epoxy resin, with the potting thickness controlled between 1 mm and 3 mm. After the epoxy resin has fully cured, a second potting process is performed using monocrystalline silicone, with a potting thickness of 0.5 mm to 2 mm.

2. The heat dissipation fan packaging process according to claim 1, characterized in that, In the epoxy resin potting step, the potting thickness of the epoxy resin is 1.5 mm to 2.5 mm.

3. The heat dissipation fan packaging process according to claim 1, characterized in that, In the monocrystalline silicone potting step, the potting thickness of the monocrystalline silicone is 0.8 mm to 1.5 mm.

4. The heat dissipation fan packaging process according to claim 1, characterized in that, The epoxy resin needs to be preheated before use. The preheating temperature is controlled between 40°C and 60°C, and the preheating time is 30 minutes to 1 hour to reduce the viscosity of the epoxy resin and improve its fluidity and potting effect. At the same time, the monocrystalline silicone also needs to be degassed before use to eliminate air bubbles and ensure potting quality.

5. The heat dissipation fan packaging process according to claim 1, characterized in that, During the potting process, a segmented potting method should be adopted, that is, the core area of ​​the motor part should be potted first, and after it has initially cured, the outer area should be potted. This is to avoid the internal stress caused by the volume shrinkage of the potting material during the curing process from adversely affecting the electronic components. At the same time, segmented potting also helps to improve the filling rate and density of the potting material.

6. The heat dissipation fan packaging process according to claim 1, characterized in that, The process also includes a thorough cleaning of the circuit board before potting, using professional cleaning agents and tools to remove oil, dust and other impurities from the circuit board surface to ensure good adhesion and conductivity between the potting material and the circuit board.

7. The heat dissipation fan packaging process according to claim 1, characterized in that, The process also includes conducting comprehensive performance tests on the cooling fan after potting, including heat dissipation performance tests, waterproof performance tests, and electrical performance tests, to ensure that all performance indicators of the cooling fan meet the design requirements and have stable and reliable working capabilities.

8. The heat dissipation fan packaging process according to claim 1, characterized in that, In the monocrystalline silicone potting step, the curing time of the monocrystalline silicone must be strictly controlled within the range of 12 to 24 hours to ensure that it is fully cured and achieves the best physical and chemical properties, while avoiding adverse effects on electronic components caused by excessively long or short curing times.

9. The heat dissipation fan packaging process according to claim 1, characterized in that, The process also includes a detailed visual inspection of the cooling fan after the potting material has cured, using professional testing tools and methods to check for bubbles and cracks on the surface of the cooling fan, in order to ensure the appearance quality and aesthetics of the product.

10. The heat dissipation fan packaging process according to claim 1, characterized in that, The process also includes conducting rigorous waterproof performance tests on the cooling fan after the potting material has cured. The cooling fan is placed in a simulated underwater or humid environment to observe whether it can work normally and maintain stable performance, so as to ensure the reliability and durability of the product in actual applications.

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