Novel tinning method

Abstract

The invention relates to the technical field of electronic manufacturing, and discloses a novel tin coating method, which is applied to processing on a PCB (Printed Circuit Board), and comprises the following steps: S1, printing solder paste on the PCB through a steel mesh, and forming a solder paste layer on the PCB; s2, mounting an SMT (Surface Mount Technology) element on the solder paste layer of the PCB; s3, reflow soldering is carried out on the PCB on which the SMT element is mounted through reflow soldering equipment, and before the step S1, the method further comprises the steps that S101, the PCB is covered with ink; and in the step S3, the hot air frequency in the reflow soldering equipment is not higher than 1680 turns per minute. In this way, the automation degree is high, and the quality of machined products is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of electronic manufacturing, and in particular to a novel tinning method. Background Art

[0002] In the process of producing gold-plated components by surface mount technology (SMT), the defect of "gold brittleness" will occur: the microstructure of the solder joints will coarsen and generate holes, and the macroscopic solder joints will produce cold solder joints, lose luster, become multi-granular, reduce ductility, greatly reduce mechanical strength, and even cause embrittlement and cracking. At present, the industry's response to the "gold brittleness" phenomenon is to "remove gold" to improve it, and the method of removing gold is tin plating, which is to add a layer of tin on the surface of the pins of the gold-plated components in advance, and then solder these "remove gold" components to the normal board.

[0003] In the traditional tinning process of printed circuit boards (PCB boards), manual operation is required, which is inefficient and prone to errors, resulting in inconsistent tin amounts on various components, affecting product quality. Therefore, it is necessary to invent a new tinning method. Summary of the invention

[0004] The purpose of the present invention is to provide a novel tin plating method with a high degree of automation and ensure the quality of processed products.

[0005] To achieve the above object, the present invention provides the following technical solutions: A novel tin-plating method is applied to the processing on a PCB board, comprising: S1. printing solder paste on the PCB board through a steel mesh, and forming a solder paste layer on the PCB board; S2. mounting SMT components on the solder paste layer of the PCB board; S3. reflow soldering the PCB board mounted with the SMT components through a reflow soldering device, wherein, before the step S1, it also comprises a step S101. covering the PCB board with ink; in the step S3, the hot air frequency in the reflow soldering device is not higher than 1680 revolutions per minute.

[0006] Preferably, the thickness of the steel mesh is 0.12MM, the length of the opening on the steel mesh is 1.8MM, and the width of the opening on the steel mesh is 0.28MM.

[0007] Preferably, in the step S2, the SMT component is mounted on the solder paste layer of the PCB board by a placement machine.

[0008] Compared with the prior art, the beneficial effects of the present invention are: a steel mesh is used to complete the arrangement of solder paste on the PCB board, and after the solder paste layer is formed, the SMT components are directly mounted on the solder paste layer, and finally the SMT tin-plating process is realized after reflow soldering. The entire process realizes the automation of the entire tin-plating process, reduces manual intervention, facilitates operation, and is highly efficient. At the same time, the amount of tin of all components can be kept consistent, the quality is controlled, and the quality of the product is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a flow chart of the new tinning method. Implementation

[0010] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0011] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0012] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0013] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0014] refer to Figure 1The present invention proposes a novel tin-plating method, which is particularly applicable to the processing on PCB boards, and includes the following steps: S1. Printing solder paste on the PCB board through a steel mesh, and forming a solder paste layer on the PCB board; S2. Mounting SMT components on the solder paste layer of the PCB board; S3. Reflow soldering the PCB board mounted with the SMT components through a reflow soldering device. Through the above method, a steel mesh is used to complete the arrangement of solder paste on the PCB board, and after the solder paste layer is formed, the SMT components are directly mounted on the solder paste layer, and finally the SMT tin-plating process is realized after reflow soldering. The present invention realizes the automation of the entire tin-plating process, reduces manual intervention, is convenient to operate, and has high efficiency. At the same time, the amount of tin of all components can be kept consistent, the quality is controlled, and the quality of the product is improved.

[0015] As a preferred embodiment, in step S1 of the present embodiment, the process of printing solder paste on the PCB to form a solder paste layer can be achieved by using a special steel mesh. The thickness of the steel mesh is 0.12MM, and the length of the opening on the steel mesh is 1.8MM and the width is 0.28MM. By accurately controlling the parameters of the steel mesh in this way, it can be ensured that the solder paste is evenly distributed on the PCB. Among them, the size setting of the steel mesh has an important influence on the printing quality of the solder paste, and the thickness, opening length and width of the steel mesh need to be determined according to the design of the PCB and the size of the SMT component. First, the thickness of the steel mesh determines the thickness of the solder paste printed on the PCB. In the present invention, the thickness of the steel mesh is set to 0.12MM, which is to ensure that a tin layer of appropriate thickness can be formed after the solder paste is printed, which can ensure the welding quality and will not cause solder paste waste. Secondly, the length and width of the opening on the steel mesh determine the area of ​​the solder paste printed on the PCB, thereby affecting the area of ​​the solder paste layer formed subsequently. In the present invention, the opening length is set to 1.8MM and the width is set to 0.28MM. This can ensure that the solder paste is accurately printed on the PCB board. These parameters are the results obtained through experimental optimization, which can ensure that the solder paste printing quality is stable and accurate during the tinning process, and can adapt to various SMT components of different sizes and shapes. Secondly, the method of placing solder paste on the PCB board using a steel mesh has well replaced the traditional way of manually placing solder paste, and has well solved the shortcomings existing in the background technology, improved production efficiency, and has a high degree of automation. Secondly, in order to achieve tinning on the PCB board, before the step S1, it also includes a step S101. Covering ink on the PCB board. By fully covering the ink on the PCB board, when the solder paste is arranged on the PCB board covered with ink, it can be ensured that the SMT components with solder paste can be picked up after reflow soldering, and then the printing of solder paste and the patch of SMT components can be assisted on the PCB board by adding optical positioning points, helping to determine the position and accuracy of solder paste printing and patch. This helps to ensure the accurate alignment of component pins with solder paste and avoid defects such as tinning and tinning.

[0016] As another preferred embodiment, in the step S3 of the present embodiment, the hot air frequency in the reflow soldering equipment is not higher than 1680 revolutions per minute, and the purpose is to prevent poor tinning caused by too high wind speed. The hot air frequency in the reflow soldering equipment is an important parameter affecting the soldering quality. If the hot air frequency is too high, the PCB board may be heated unevenly, thereby affecting the soldering quality. On the other hand, if the hot air frequency is too low, the PCB board may be heated for too long, causing damage to the PCB board and components. In the present invention, the hot air frequency in the reflow soldering equipment is controlled to be below 1680 revolutions per minute, which is a result obtained through experimental optimization, which can ensure that the PCB board is heated evenly during the reflow soldering process, while avoiding damage to the PCB board and components due to too long heating time. In this way, the stability of the tinning process can be ensured, so that the tin amount of all components can be kept consistent, and it is also beneficial to improve production efficiency and product quality.

[0017] As another preferred embodiment, in step S2, the SMT component is mounted on the PCB board by a chip mounter so that the solder paste on the PCB board is set on the SMT component. Among them, the chip mounter is a device used to accurately place surface mount technology (SMT) components on a printed circuit board (PCB). The chip mounter can quickly realize the setting between SMT components and solder paste, which well replaces the traditional processing method of manually arranging solder paste on SMT components, well solves the shortcomings of the background technology, improves production efficiency, and has a high degree of automation.

[0018] As another preferred embodiment, the reflow soldering used in step S3 is a commonly used electronic component soldering technology, especially in surface mount technology (SMT), which is a key step in reflow soldering of SMT components that have been arranged on a PCB board with solder paste. During the reflow soldering process, the solder paste previously arranged on the PCB board will be heated to a molten state, and then cooled and solidified as the temperature decreases, thereby forming a stable arrangement on the SMT component, which has the advantages of high efficiency, high quality and high degree of automation.

[0019] The above is only a preferred embodiment of the present invention. For ordinary technicians in this field, various changes and modifications can be made without departing from the spirit and scope of the present invention. For example, in step S1, other types of templates can be used to print solder paste; in step S2, other types of equipment can be used to mount SMT components; in step S3, the hot air frequency in the reflow soldering equipment can also be adjusted to adapt to different types of PCB boards and SMT components.

[0020] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A new tinning method, applied to the processing of PCB boards, characterized in that: include: S1. Printing solder paste on the PCB through a steel mesh and forming a solder paste layer on the PCB; S2. Mounting the SMT components on the solder paste layer of the PCB board; S3. reflow the PCB board mounted with the SMT components through a reflow device, Before the step S1, the step S101 is also included. Covering the PCB board with ink; In the step S3, the hot air frequency in the reflow soldering equipment is not higher than 1680 revolutions per minute.

2. The novel tinning method according to claim 1 is characterized in that: The thickness of the steel mesh is 0.12MM, the length of the opening on the steel mesh is 1.8MM, and the width of the opening on the steel mesh is 0.28MM.

3. The novel tinning method according to claim 1 is characterized in that: In the step S2, the SMT component is mounted on the solder paste layer of the PCB board by a placement machine.

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