PCB two-printing through hole tin filling structure

By forming a drainage solder paste coating on the inner wall of the PCB board through-hole and combining it with the secondary reflow of the second printed solder paste, the problem of insufficient solder paste filling in the through-hole of the PCB board with small pin spacing is solved, efficient soldering shaping is achieved, and the phenomenon of cold soldering and bridging is avoided.

CN223452182UActive Publication Date: 2025-10-17HUIZHOU YAXINGDA TECHNOLOGY CO LTD
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Patent Information

Application Number
CN202422912061.7
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-11-27
Publication Date
2025-10-17
Estimated Expiration
2034-11-27

AI Technical Summary

Technical Problem

In the prior art, when the pin pitch is less than or equal to 1.5 mm and the through-holes of the PCB board are relatively dense, it is difficult for liquid solder paste to fully fill the through-holes, resulting in problems such as cold solder joints and solder bridging between pins.

Method used

The system employs a dual-printed solder paste structure. A flow-guiding solder paste coating is formed by a single reflow soldering process and adheres to the inner wall of the via. Then, a second printing of solder paste is applied to the other side of the PCB board and adheres to the flow-guiding solder paste coating. A second reflow soldering process is then performed to fuse the two printing of solder pastes together and fully fill the via.

Benefits of technology

It effectively avoids the problem of cold solder joints and bridging between pins caused by insufficient solder paste filling in the through-hole, ensuring the soldering quality.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model provides a PCB two-printing through hole tin filling structure. The PCB two-printing through hole tin filling structure comprises a PCB, a one-printing tin paste body and a two-printing tin paste body. The PCB is provided with a through hole, and the through hole is used for the insertion of a pin. A through hole is formed in the PCB, one solder paste body is printed on one surface of the PCB, one solder paste body is attached around one end of the through hole, the other solder paste body forms a drainage solder paste coating after being subjected to one-time reflow soldering, and the drainage solder paste coating is attached to the inner wall of the through hole; and the second printed solder paste body is printed on the other surface of the PCB, the second printed solder paste body is attached to the other end of the through hole and adhered to the drainage solder paste coating, and the second printed solder paste body is fused with the drainage solder paste coating after being subjected to secondary reflow soldering and forms the pin. According to the PCB two-printing through hole tin filling structure of the utility model, during the secondary reflow soldering, the liquid-state two-printing solder paste is guided to the interior of the through hole through the liquid-state drainage solder paste coating and is fused, so that the through hole can be fully filled with the liquid-state two-printing solder paste, and therefore, the purpose of welding and shaping pins can be realized, pseudo soldering caused by insufficient filling of the solder paste in the through hole can be avoided, and the reliability of the PCB can be improved. And tin connection between the pins is avoided.
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Description

Technical Field

[0001] The utility model relates to the technical field of SMT patch processing, in particular to a PCB board double-printed through-hole tin-filling structure. Background Art

[0002] SMT is the abbreviation of Surface Mount Technology, also known as surface mounting or surface mounting technology. It is a circuit assembly technology that mounts pinless or short-lead surface mounting components on the surface of a printed circuit board (PCB) or other substrate, and assembles them by soldering or wave soldering. Among them, reflow soldering mainly heats the solder paste that has been applied on the PCB board to transform the solder paste from solid or semi-solid state to liquid state and then to solid state, and the final solid solder paste is used to solder the pins of the finalized electronic components.

[0003] In the existing technology, surface-mount electronic components are usually directly soldered to the surface of the PCB board through reflow soldering, while plug-in electronic components usually use wave soldering to solder their pins into the through-holes of the PCB board. At the same time, the industry generally believes that pin spacing greater than or equal to 2mm is more suitable for wave soldering.

[0004] However, when the pin pitch is less than or equal to 1.5mm, and the through-holes of the PCB board are densely packed and the through-hole apertures are also large, for example, when the pins of the plug-in electronic components are positioned in the through-holes for wave soldering, it is difficult for the liquid solder paste to fully fill the through-holes, which can easily cause solder joints between the pins and insufficient solder paste filling in the through-holes, resulting in cold solder joints. Utility Model Content

[0005] The purpose of the utility model is to overcome the shortcomings of the prior art and provide a PCB board double-printed through-hole tin filling structure that can fully fill the through-holes of the PCB board with solder paste and better shape the pin welding, thereby effectively avoiding the problem of cold solder joints caused by insufficient solder paste filling in the through-holes and the problem of tin connection between pins.

[0006] The purpose of this utility model is achieved through the following technical solutions:

[0007] A PCB board double-printed through-hole tin-filling structure, comprising:

[0008] The PCB board is provided with through holes for inserting pins;

[0009] A first solder paste is printed on one side of the PCB, and the first solder paste is attached around one end of the through-hole, and the first solder paste forms a lead-in solder coating after one reflow soldering, and the lead-in solder coating is attached to the inner wall of the through-hole;

[0010] A second solder paste is printed on the other side of the PCB, and the second solder paste is attached to the other end of the through-hole and adheres to the lead-in solder coating, and the second solder paste is fused with the lead-in solder coating and shapes the pin after two reflow solderings.

[0011] In one embodiment, the cross section of the second solder paste is trapezoidal or rectangular.

[0012] In one embodiment, the large end of the second solder paste faces the other side of the PCB and covers the other end of the through-hole.

[0013] In one embodiment, the average roughness of the inner wall of the through-hole is less than or equal to 0.2 microns.

[0014] In one embodiment, the through-hole is a circular through-hole.

[0015] In one embodiment, the diameter of the through-hole is less than or equal to 1.2 millimeters.

[0016] In one embodiment, the first solder paste is in the form of a circular ring.

[0017] Compared with the prior art, the PCB two-print through-hole solder filling structure has at least the following advantages:

[0018] After one reflow soldering, the first solder paste forms a lead-in solder coating and is attached to the inner wall of the through-hole; in this way, the second solder paste is printed on the other side of the PCB, and the second solder paste is attached to the other end of the through-hole and adheres to the lead-in solder coating, so that the second solder paste can be guided to the inside of the through-hole by the liquid lead-in solder coating and fused when the second solder paste is subjected to two reflow solderings, so as to be filled in the through-hole, thereby achieving the purpose of welding and shaping the pin. The PCB two-print through-hole solder filling structure effectively replaces the method of directly positioning the pin in the through-hole for wave soldering in the prior art, so as to avoid the problems of insufficient solder filling in the through-hole and continuous soldering between the pins. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation to the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the premise of the drawings.

[0020] Figure 1 PCB board two printing via hole filling tin structure of an embodiment is shown in the sectional view;

[0021] Figure 2 PCB board two printing via hole filling tin structure of an embodiment is shown in the sectional view; Figure 1 PCB board two printing via hole filling tin structure of an embodiment is shown in the sectional view;

[0022] Figure 3 PCB board two printing via hole filling tin structure of an embodiment is shown in the sectional view; Figure 1 PCB board two printing via hole filling tin structure of an embodiment is shown in the sectional view;

[0023] Figure 4 PCB board two printing via hole filling tin structure of an embodiment is shown in the sectional view; Figure 1 PCB board two printing via hole filling tin structure of an embodiment is shown in the sectional view;

[0024] Reference signs: PCB board two printing via hole filling tin structure 10;PCB board 100;Via hole 101;Pin 200;One printing tin paste body 300;Drainage tin paste coating 310;Two printing tin paste body 400;Steel mesh 500. DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the present application, the present application will be described more fully with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0026] It should be noted that when an element is referred to as being "fixed" to another element, it can be directly on the other element or there can be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be an intervening element. The terms "vertical", "horizontal", "left", "right", and similar expressions used herein are for illustrative purposes only, and are not intended to be the only implementation.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of this invention are intended solely for the purpose of describing specific embodiments and are not intended to limit this invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] The present disclosure provides a PCB board double-printed through-hole tin filling structure, comprising a PCB board, a first-printed tin paste, and a second-printed tin paste. The PCB board has a through-hole for inserting a pin; the first-printed tin paste is printed on one side of the PCB board, surrounding one end of the through-hole and adhering thereto; the first-printed tin paste forms a drainage tin paste coating after a single reflow, and the drainage tin paste coating adheres to the inner wall of the through-hole; the second-printed tin paste is printed on the other side of the PCB board, adhering to the other end of the through-hole and adhering to the drainage tin paste coating; the second-printed tin paste fuses with the drainage tin paste coating after a second reflow, and shapes the pin.

[0029] See also Figures 1 to 4 In order to better understand the PCB board double-printed through-hole tin-filling structure 10 of the present application, the PCB board double-printed through-hole tin-filling structure 10 is further explained below:

[0030] A PCB board double-printed through-hole tin filling structure 10 according to one embodiment includes a PCB board 100, a first-printed tin paste 300, and a second-printed tin paste 400. The PCB board 100 has a through-hole 101 for inserting a pin 200. The first-printed tin paste 300 is printed on one side of the PCB board 100 and adheres around one end of the through-hole 101. After a single reflow, the first-printed tin paste 300 forms a drainage solder paste coating 310, which adheres to the inner wall of the through-hole 101. The second-printed tin paste 400 is printed on the other side of the PCB board 100 and adheres to the other end of the through-hole 101 and adheres to the drainage solder paste coating 310. After a second reflow, the second-printed tin paste 400 fuses with the drainage solder paste coating 310 and shapes the pin 200.

[0031] In the embodiment, a first solder paste 300 is formed into a flow guide solder paste coating 310 and attached to the inner wall of the through hole 101 by reflow soldering; then, a second solder paste 400 is printed on the other side of the PCB 100, so that the second solder paste 400 is attached to the other end of the through hole 101 and adheres to the flow guide solder paste coating 310, and thus the second solder paste 400 can be guided by the liquid flow guide solder paste coating 310 to the inside of the through hole 101 and fused to fill the through hole 101 during the second reflow soldering, so as to achieve the purpose of welding the shaped pin 200. The PCB 100 two-print through hole 101 soldering structure 10 of the utility model effectively replaces the prior art mode of positioning the pin 200 in the through hole 101 for peak soldering, so as to avoid the problem of insufficient solder filling in the through hole 101 and the problem of soldering between the pins 200.

[0032] It should be noted that the second solder paste 400 and the flow guide solder paste coating 310 are heated to a liquid state by high temperature during the second reflow soldering. It can be understood that, due to the thinness of the flow guide solder paste coating 310, the flow guide solder paste coating 310 melts into a liquid state before the second solder paste 400, and thus the second solder paste 400 is effectively guided by the liquid flow guide solder paste coating 310 to the inside of the through hole 101 during the melting process of the second solder paste 400.

[0033] As shown in Figure 1 In one embodiment, the cross section of the second solder paste 400 is trapezoidal or rectangular.

[0034] It can be understood that, in the embodiment, the second solder paste 400 is formed by screen printing through the steel screen 500 with a trapezoidal cross section, so that the second solder paste 400 with a trapezoidal cross section can provide a larger amount of solder filling for the through hole 101 with a larger volume, that is, the volume of the second solder paste 400 with a trapezoidal cross section is larger than that of the second solder paste 400 with a rectangular cross section, so as to effectively ensure the density of solder filling in the through hole 101, thereby avoiding the problem of false welding in the through hole 101, and further effectively ensuring the welding quality of the plug-in electronic component.

[0035] As shown in Figure 3 and Figure 4 In one embodiment, the large end of the second solder paste 400 faces the other side of the PCB 100 and covers the other end of the through hole 101. In this way, the second solder paste 400 can be better attached to the other end of the through hole 101 by the solder paste printing process and adhered to the flow guide solder paste coating 310, so that the second solder paste 400 can be guided by the liquid flow guide solder paste coating 310 to the inside of the through hole 101 and fused to fill the through hole 101 during the second reflow soldering, so as to achieve the purpose of welding the shaped pin 200.

[0036] As Figure 1 shown, in one embodiment, the average roughness of the inner wall of the through hole 101 is less than or equal to 0.2 microns.

[0037] It can be understood that the better average roughness (Ra) is the key to ensure the good conductivity of the through hole 101, and in this embodiment, the average roughness of the through hole 101 is 0.18 microns.

[0038] As Figure 1 shown, in one embodiment, the through hole 101 is a circular through hole 101. In this way, the processing of the through hole 101 is facilitated.

[0039] As Figure 1 shown, in one embodiment, the diameter of the through hole 101 is less than or equal to 1.2 millimeters.

[0040] As Figure 1 and Figure 2 shown, in one embodiment, the tin paste body 300 is in the form of a ring.

[0041] It can be understood that in this embodiment, the through hole 101 is a circular through hole 101, and therefore a tin paste body 300 is attached around one end of the circular through hole 101, so that during the first reflow soldering process, the tin paste body 300 can gradually flow from the liquid state to the inner wall of the circular through hole 101 from one end of the circular through hole 101, and when the first reflow soldering process is completed, the drainage tin paste coating 310 is formed and attached to the inner wall of the circular through hole 101.

[0042] Compared with the prior art, the utility model has at least the following advantages:

[0043] After the first reflow soldering, the tin paste body is formed into a drainage tin paste coating and attached to the inner wall of the through hole; in this way, the second tin paste body is printed on the other side of the PCB board, and the second tin paste body is attached to the other end of the through hole and adhered to the drainage tin paste coating, so that the second tin paste body can be drained to the inside of the through hole by the liquid drainage tin paste coating during the second reflow soldering and fused to fill the through hole, thereby achieving the purpose of welding the shaped pin. The PCB board two-print-through-hole tin filling structure of the utility model effectively replaces the method of directly positioning the pin in the through hole for wave soldering in the prior art, thereby avoiding the problem of insufficient tin paste filling in the through hole and the problem of tin connection between the pins.

[0044] The above-described embodiments only express several implementation manners of the utility model, the description is more specific and detailed, but can not therefore be understood as the limitation of the utility model patent range. It should be pointed out that for ordinary skilled person in the art, without departing from the utility model concept, several modifications and improvements can be made, which belong to the protection range of the utility model. Therefore, the protection range of the utility model patent should be subject to the appended claims.

Claims

1. A PCB board double-printed through-hole tin-filling structure, characterized in that: include: The PCB board is provided with through holes for inserting pins; a printed tin paste, the printed tin paste being printed on one side of the PCB board, the printed tin paste being attached around one end of the through hole, the printed tin paste being subjected to a single reflow process to form a drainage tin paste coating, the drainage tin paste coating being attached to an inner wall of the through hole; A second-printed tin paste is printed on the other side of the PCB board, the second-printed tin paste is attached to the other end of the through hole, and adheres to the drainage tin paste coating. After the second reflow, the second-printed tin paste is fused with the drainage tin paste coating and shapes the pin.

2. The PCB board double-printed through-hole tin-filling structure according to claim 1, characterized in that: The cross section of the second-printed solder paste is trapezoidal or rectangular.

3. The PCB board double-printed through-hole tin-filling structure according to claim 2, characterized in that: The large end of the second printed solder paste faces the other side of the PCB board and covers the other end of the through hole.

4. The PCB board double-printed through-hole tin-filling structure according to claim 1, characterized in that: The average roughness of the inner wall of the through hole is less than or equal to 0.2 micrometers.

5. The PCB board double-printed through-hole tin-filling structure according to claim 1, characterized in that: The through hole is a circular through hole.

6. The PCB board double-printed through-hole tin-filling structure according to claim 5, characterized in that: The diameter of the through hole is less than or equal to 1.2 mm.

7. The PCB board double-printed through-hole tin-filling structure according to claim 5, characterized in that: The solder paste is in a ring shape.