Encapsulation process for disc capacitors

Abstract

The embodiment of the present application provides a kind of encapsulation process method of wafer capacitor, which comprises: the wafer capacitor preheated to first preset temperature is immersed in epoxy resin powder for first preset time length;The epoxy resin powder on the surface of the wafer capacitor is melted at second preset temperature, and the hot melting time reaches second preset time length, to form first encapsulation layer;Change the adhesion of epoxy resin powder, immerse the wafer capacitor encapsulated with the first encapsulation layer in the epoxy resin powder with changed adhesion for the first preset time length;The epoxy resin powder on the surface of the first encapsulation layer is melted at the second preset temperature, and the hot melting time reaches second preset time length, to form second encapsulation layer.The scheme can improve product size consistency, improve production efficiency and reduce production cost.

Description

Technical Field

[0001] This invention relates to the field of capacitor technology, and in particular to a method for encapsulating a disc capacitor. Background Technology

[0002] Epoxy resin powder has good insulation and physical protection properties. Encapsulation with epoxy resin powder is one of the most common encapsulation processes for disc capacitors. The common process on the market is to use epoxy resin powder to encapsulate three layers: the first layer is the base layer, which is responsible for insulation; the second layer is the thickening layer, which is responsible for physical properties; and the third layer is the protective layer, which is responsible for external contact and reaction.

[0003] Existing technologies for encapsulating wafer capacitors with epoxy resin powder require three layers, which has the following disadvantages: a more complex process, poorer dimensional consistency, greater waste of energy and raw materials, and lower production efficiency. Encapsulation requires heating the product and then immersing it in the powder, relying on high-temperature melting of the epoxy resin powder to form the encapsulation layer. The encapsulated layer has a certain dimensional error; each additional layer amplifies this error. Furthermore, to ensure the minimum encapsulation size, more epoxy resin powder is used in the remaining parts, resulting in considerable waste. Each additional layer adds a process step and wastes energy, further reducing production efficiency. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide an encapsulation process for a wafer capacitor to solve the technical problems of cumbersome process, poor dimensional consistency, high production cost, and low production efficiency in the encapsulation of wafer capacitors in the prior art. The encapsulation process includes: The preheated disc capacitor is immersed in epoxy resin powder for a first preset time. The epoxy resin powder on the surface of the disc capacitor is heated and melted at a second preset temperature, and the hot melting time reaches a second preset duration to form a first encapsulation layer; The adhesion of epoxy resin powder is changed, and a disc capacitor encapsulated with the first encapsulation layer is immersed in epoxy resin powder with the changed adhesion for the first preset time. The epoxy resin powder on the surface of the first encapsulation layer is heated and melted at the second preset temperature, and the hot melting time reaches the second preset duration to form the second encapsulation layer.

[0005] Compared with the prior art, the beneficial effects that can be achieved by the above-mentioned at least one technical solution adopted in the embodiments of this specification include at least the following: by immersing a disc capacitor preheated to a first preset temperature into epoxy resin powder for a first preset time, and then heating and melting the epoxy resin powder on the surface of the disc capacitor at a second preset temperature for a second preset time, forming a first encapsulation layer, thereby proposing to change the adhesion of the epoxy resin powder, immersing the disc capacitor encapsulated with the first encapsulation layer into the epoxy resin powder with the changed adhesion for the first preset time, and heating and melting the epoxy resin powder on the surface of the first encapsulation layer at the second preset temperature. The resin powder, after being heated for a second preset time, forms a second encapsulation layer. This achieves the goal of encapsulating two layers of the disc capacitor using the same epoxy resin powder without affecting its main performance. These two encapsulation layers can achieve the performance that previously required three layers in existing technologies. This reduces the number of encapsulation steps and processes, thereby simplifying the encapsulation process, increasing efficiency, and saving on labor and electricity costs. It also minimizes dimensional fluctuations, improving the consistency of encapsulation dimensions, and reduces or eliminates energy and raw material waste, thus lowering production costs and increasing production efficiency. Attached Figure Description

[0006] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0007] Figure 1 This is a flowchart of an encapsulation process for a disc capacitor provided in an embodiment of the present invention. Detailed Implementation

[0008] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0009] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0010] In this embodiment of the invention, a method for encapsulating a wafer capacitor is provided, such as... Figure 1 As shown, the method includes: Step S101: Immerse the preheated disc capacitor to a first preset temperature into epoxy resin powder (the epoxy resin powder is used at a temperature of 30℃±4℃) for a first preset time. Step S102: Heat and melt the epoxy resin powder on the surface of the disc capacitor at a second preset temperature, and heat melt for a second preset time to form a first encapsulation layer; Step S103: Change the adhesion of epoxy resin powder, immerse the disc capacitor encapsulated with the first encapsulation layer into the epoxy resin powder with changed adhesion for the first preset time. Step S104: Heat and melt the epoxy resin powder on the surface of the first encapsulation layer at the second preset temperature, and the hot melting time reaches the second preset duration to form the second encapsulation layer.

[0011] In practical implementation, the two encapsulation layers mentioned above can achieve the performance that originally required three encapsulation layers in the prior art, and the encapsulation dimensions of the two encapsulation layers are consistent with the encapsulation dimensions of the original three encapsulation layers. Specifically, the first encapsulation layer can have the same encapsulation dimensions and function as the first layer in the original three-layer encapsulation, for example, serving as a base layer and primarily responsible for insulation performance; the encapsulation dimensions of the second encapsulation layer are consistent with the sum of the encapsulation dimensions of the second and third layers in the original three-layer encapsulation, serving as a thickening layer and protective layer, primarily responsible for physical properties, external contact, and reaction.

[0012] To achieve the dimensions and properties of the second encapsulation layer, a method was proposed to modify the adhesion of the epoxy resin powder (i.e., improve adhesion). Stronger adhesion results in a thicker coating on the product, allowing for a reduction in the number of encapsulation layers while maintaining the same encapsulation thickness. This improves efficiency and reduces production costs without compromising performance. Furthermore, the dimensions and properties of the encapsulation layer can be modified and adjusted within a single encapsulation process to complete the second encapsulation layer. This enables the use of the same epoxy resin powder to create two encapsulation layers of different sizes and properties (first and second layers) without the need for additional raw materials. Therefore, the production process is simplified, and no additional materials are required.

[0013] In practice, the applicant discovered that epoxy resin powder is a material that adheres to and melts on a heat source object when heated. The amount of heat transferred from the heat source object and the speed of heat conduction affect the thickness of the epoxy resin powder adhesion layer. Therefore, epoxy resin powder is sensitive to temperature. Appropriate heating can reduce the fluidity of epoxy resin powder, which is equivalent to increasing its viscosity, thus affecting the adhesion of epoxy resin powder.

[0014] Simply increasing the temperature of the epoxy resin powder before use can achieve the same encapsulation thickness requirement, but the electrical performance will significantly decrease after the first encapsulation layer is thickened. This is also the reason why epoxy resin powder with the same temperature cannot be used for both encapsulation layers. Alternatively, increasing the hot melt temperature can also increase the encapsulation layer thickness, but the solder joints of disc capacitors contain solder, and the melting temperature of solder on the market ranges from 183℃ to 230℃. Excessively high temperatures will affect the soldering quality of the preceding processes, thus also limiting the hot melt temperature.

[0015] Considering various factors, this application proposes to change the adhesion of epoxy resin powder by adjusting the temperature. Specifically, the epoxy resin powder is preheated to the third preset temperature and held for the third preset time to adjust the adhesion of the epoxy resin powder.

[0016] In practice, to ensure sufficient material for the second sealing layer, 20 kg of the epoxy resin powder is preheated to the third preset temperature and held for the third preset time.

[0017] In practice, under normal circumstances, the operating temperature of epoxy resin powder is 30℃±4℃. In order to change and adjust the adhesion of epoxy resin powder without affecting its normal use, the third preset temperature range is proposed to be 38℃ to 55℃. That is, preheating epoxy resin powder at any temperature within the range of 38℃ to 55℃ can change and adjust its adhesion.

[0018] Specifically, and more preferably, the third preset temperature is 40°C. For example, the epoxy resin powder is preheated at 40°C ± 2°C to change and adjust the adhesion of the epoxy resin powder.

[0019] In specific implementation, the third preset duration is 2 hours. That is, the epoxy resin powder is preheated at the third preset temperature for 2 hours to change and adjust the adhesion of the epoxy resin powder.

[0020] In practice, in the process of changing and improving the adhesion of epoxy resin powder, in addition to changing the temperature to change the adhesion of epoxy resin powder, humidity can also be controlled to change and improve the adhesion of epoxy resin powder.

[0021] In specific implementation, in order to encapsulate the first encapsulation layer on the surface of the disc capacitor, the first preset temperature is 140℃±5℃ and the preheating time is 20min, that is, the disc capacitor is preheated at a temperature of 140℃±5℃ for 20min.

[0022] In specific implementation, during the process of immersing the preheated disc capacitor to the first preset temperature into epoxy resin powder, the first preset time is 4.5 seconds, that is, the immersion time is 4.5 seconds.

[0023] In specific implementation, after impregnation, during the process of heating and melting the epoxy resin powder on the surface of the disc capacitor, the second preset temperature is 210℃±5℃, and the second preset time is 30S, that is, the temperature for heating and melting the epoxy resin powder on the surface of the disc capacitor is 210℃±5℃, and the hot melting time is 30S.

[0024] In a specific implementation, a disc capacitor encapsulated with the first encapsulation layer is immersed in epoxy resin powder with altered adhesion for the first preset time (i.e., immersion time of 4.5 seconds). Then, the epoxy resin powder on the surface of the first encapsulation layer is heated and melted at the second preset temperature for the second preset time (i.e., the temperature at which the epoxy resin powder on the surface of the first encapsulation layer is heated and melted is 210℃±5℃, and the melting time is 30 seconds) to form the second encapsulation layer.

[0025] In practice, the above-mentioned encapsulation process also includes: After encapsulating the second encapsulation layer, it is cured at 150℃±3℃ for 2 hours, and then naturally cooled to below 80℃ to complete the encapsulation process of the disc capacitor.

[0026] In practice, the following describes the operation process for implementing the encapsulation method for the above-mentioned wafer capacitors: ① Preheat the product (i.e., the disc capacitor) to 140℃±5℃ (i.e., the first preset temperature) for 20 minutes. ② Use type A epoxy resin powder (i.e., conventional epoxy resin powder), impregnate once, for 4.5 seconds (i.e., the first preset time); ③After the product is dipped in the material, it is hot-melted at a temperature of 210℃±5℃ (i.e., the second preset temperature) and a hot-melting time of 30S (i.e., the second preset duration). ④ Use type B epoxy resin powder (i.e., epoxy resin powder with modified adhesion) for the second layer of encapsulation, impregnate twice, and impregnate for 4.5 seconds (i.e. the first preset time). ⑤ After the product is impregnated, it is hot-melted at a temperature of 210℃±5℃ for 30 seconds. ⑥ After sealing with two layers, cure at 150℃±3℃ for 2 hours, then allow to cool naturally to below 80℃ before removing.

[0027] In practice, the two-layer encapsulation obtained by the above two-layer encapsulation was tested, and the test results are shown in Table 1 below. It can be clearly seen from the test results that: ① the dimensional fluctuation of the two-layer encapsulation is significantly smaller than that of the three-layer encapsulation; ② the two-layer encapsulation consumes 6.5% less epoxy resin powder than the three-layer encapsulation; ③ the average equivalent breakdown voltage of the two-layer encapsulation is 0.58KV / mm higher than that of the three-layer encapsulation.

[0028] Table 1

[0029] The embodiments of the present invention achieve the following technical effects: By immersing a disc capacitor preheated to a first preset temperature into epoxy resin powder for a first preset time, and then heating and melting the epoxy resin powder on the surface of the disc capacitor at a second preset temperature for a second preset time, a first encapsulation layer is formed. This invention proposes to modify the adhesion of the epoxy resin powder, immerse the disc capacitor encapsulated with the first encapsulation layer into the modified epoxy resin powder for the first preset time, and then heat and melt the epoxy resin powder on the surface of the first encapsulation layer at a second preset temperature for a second preset time. By setting a time limit, a second encapsulation layer is formed. This achieves the goal of encapsulating the disc capacitor with two layers of the same epoxy resin powder without affecting its main performance. These two encapsulation layers can achieve the performance that the existing technology originally required three encapsulation layers to achieve. This reduces the number of encapsulation steps and one encapsulation process, thereby reducing the complexity of the encapsulation process, making the process simpler, more efficient, and saving on labor and water and electricity costs. It also reduces dimensional fluctuations, which helps improve the consistency of encapsulation dimensions. Furthermore, it reduces or avoids the waste of energy and raw materials, which helps to reduce production costs and improve production efficiency.

[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for encapsulating a disc capacitor, characterized in that, include: The preheated disc capacitor is immersed in epoxy resin powder for a first preset time. The epoxy resin powder on the surface of the disc capacitor is heated and melted at a second preset temperature, and the hot melting time reaches a second preset duration to form a first encapsulation layer; The adhesion of epoxy resin powder is changed, and a disc capacitor encapsulated with the first encapsulation layer is immersed in epoxy resin powder with the changed adhesion for the first preset time. The epoxy resin powder on the surface of the first encapsulation layer is heated and melted at the second preset temperature, and the hot melting time reaches the second preset duration to form the second encapsulation layer.

2. The method as described in claim 1, characterized in that, Modifying the adhesion properties of epoxy resin powder includes: The epoxy resin powder is preheated to the third preset temperature and held for the third preset time to adjust the adhesion of the epoxy resin powder.

3. The method as described in claim 2, characterized in that, Preheat the epoxy resin powder to a third preset temperature and maintain it for a third preset time, including: Take 20 kg of the epoxy resin powder, preheat it to the third preset temperature, and maintain it for the third preset time.

4. The method as described in claim 2, characterized in that, The third preset temperature ranges from 38°C to 55°C.

5. The method as described in claim 2, characterized in that, The third preset temperature is 40℃.

6. The method as described in claim 2, characterized in that, The third preset duration is 2 hours.

7. The method according to any one of claims 1 to 6, characterized in that, The first preset temperature is 140℃±5℃, and the preheating time is 20min.

8. The method according to any one of claims 1 to 6, characterized in that, The first preset duration is 4.5 seconds.

9. The method according to any one of claims 1 to 6, characterized in that, The second preset temperature is 210℃±5℃, and the second preset duration is 30S.

10. The method according to any one of claims 1 to 6, characterized in that, Also includes: After encapsulating the second encapsulation layer, it is cured at 150℃±3℃ for 2 hours, and then naturally cooled to below 80℃ to complete the encapsulation process of the disc capacitor.

Images