Steel mesh structure for improving welding effect of parallel devices

Abstract

The utility model discloses a steel mesh structure for improving the welding effect of parallel devices, which comprises a plurality of parallel opening parts, each parallel opening part comprises two pairs of steel mesh openings arranged at intervals, each parallel opening part corresponds to a bonding pad on a circuit board, and the device specification corresponding to each pair of steel mesh openings is smaller than the device specification corresponding to the bonding pad. Each bonding pad comprises two welding spots, and the two steel mesh openings in each pair are located on the two welding spots of one bonding pad respectively. According to the utility model, by controlling the size and position of the opening of the steel mesh, the accurate positioning and stable mounting of the device in the welding process are ensured, two small-specification devices are accurately placed on a large-specification bonding pad, and the four steel mesh openings corresponding to the two devices are mutually independent, so that the welding efficiency is improved. According to the invention, large tension or traction force is not generated in the welding furnace passing process of the devices, collision and interference between the devices are prevented, parallel welding of the devices is realized, the original bonding pad design does not need to be changed, and the cost loss of remanufacturing a board caused by the design problem is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit board production, and more particularly to a steel mesh structure for improving the welding effect of parallel devices. Background Art

[0002] During the electronic product board design phase, the pad design failed to fully consider product performance, resulting in unstable product performance after soldering according to the bill of materials. Since the board had already been fabricated, re-making the board was costly. Analysis and debugging by product engineers determined that to meet current product performance requirements, soldering two components in parallel on certain pads would stabilize product performance and avoid re-making the board. However, soldering two components in parallel on the same pad would cause them to collide and interfere with each other, and would also affect components on adjacent pads.

[0003] How to solve the mutual collision and interference problems caused by parallel soldering of two devices without changing the existing PCB board. Summary of the Invention

[0004] In order to solve the problems of mutual collision and interference generated when two devices are welded in parallel on the same pad, the utility model provides a steel mesh structure for improving the welding effect of parallel devices.

[0005] The technical solution of this utility model is as follows:

[0006] A steel mesh structure for improving the welding effect of parallel devices includes several parallel opening parts, each of which includes two pairs of steel mesh openings arranged at intervals. Each of the parallel opening parts corresponds to a soldering pad on a circuit board. The device specifications corresponding to each pair of the steel mesh openings are smaller than the device specifications corresponding to the soldering pad. The soldering pad includes two solder points. Each pair of two steel mesh openings is respectively located on the two solder points of one soldering pad.

[0007] Furthermore, the two pairs of steel meshes are symmetrically arranged about a horizontal line, and the horizontal center line and the vertical center line of the parallel opening portion are collinear with the horizontal center line and the vertical center line of the welding pad respectively.

[0008] Furthermore, the side of the two pairs of steel mesh openings away from each other is the first side, the side opposite to the first side is the second side, the side adjacent to the left of the first side is the third side, the side adjacent to the right of the first side is the fourth side, and the first side exceeds the edge of the welding point.

[0009] Furthermore, the first side and adjacent sides are both provided with chamfers.

[0010] Furthermore, the horizontal length of the chamfer is 1 / 4 to 1 / 2 of the length of the first side. Preferably, the horizontal length of the chamfer is 1 / 3 of the length of the first side. Specifically, when the pair of stencil openings is used to weld 0201-sized components, if the length of the first side is 0.3 mm, the horizontal length of the chamfer is 0.1 mm.

[0011] Furthermore, the vertical length of the chamfer is 1 / 4 to 1 / 2 of the length of the third side. Preferably, the vertical length of the chamfer is 1 / 3 of the length of the third side. Specifically, when the pair of stencil openings is used to weld 0201-sized components, if the length of the third side is 0.3 mm, the vertical length of the chamfer is 0.1 mm.

[0012] Furthermore, the length of the chamfer in the horizontal direction is equal to the length in the vertical direction.

[0013] Furthermore, the first side, the second side, the third side and the fourth side are all provided with rounded corners between adjacent sides.

[0014] Furthermore, the radius of the fillet is 1 / 7 to 1 / 5 of the length of the first side. Preferably, the radius of the fillet is 1 / 6 of the length of the first side. Specifically, when the pair of stencil openings is used to weld 0201-sized components, if the length of the first side is 0.3 mm, the radius of the fillet is 0.05 mm.

[0015] Furthermore, the spacing between the two pairs of stencil openings is 0.3 to 0.5 times the length of the third side. Preferably, the spacing between the two pairs of stencil openings is 0.4 times the length of the third side. Specifically, when the pair of stencil openings is used to solder 0201-sized components, the length of the third side is 0.3 mm, and the spacing between the two pairs of stencil openings is 0.12 mm.

[0016] Furthermore, the spacing between each pair of two stencil openings is 0.7 to 0.9 times the length of the first side. Preferably, the spacing between each pair of two stencil openings is 0.783 times the length of the first side. Specifically, when the pair of stencil openings is used to solder 0201-sized components, if the length of the first side is 0.3 mm, the spacing between the pair of stencil openings is 0.235 mm.

[0017] The utility model according to the above solution has the following beneficial effects:

[0018] 1. The utility model ensures the accurate positioning and stable mounting of devices during the welding process by precisely controlling the size and position of the steel mesh openings, and accurately places two small-sized devices on a large-sized pad, thereby achieving precise placement of the devices on the pads. The four steel mesh openings corresponding to the two parallel devices are independent of each other, preventing the devices from generating large tension or traction during the welding process, preventing collisions and interference between devices, and achieving parallel welding of devices without changing the original pad design. At the same time, it avoids the cost loss of re-boarding due to board design problems, and ensures the quality and reliability of the product. In addition, the steel mesh structure also improves the accuracy and stability of welding, which significantly improves the welding quality.

[0019] 2. The utility model sets chamfers on the openings of the steel mesh so that most of the solder paste can fall accurately on the pad, reducing the unnecessary distribution of solder paste on the outside of the pad. In addition, there is a large enough area of ​​solder paste on the pad so that the device can be placed stably on the solder paste when mounting the device. During the reflow soldering process, as the solder paste melts and flows, the less solder paste on the outside of the pad will naturally converge to the inside of the pad, effectively filling the gap between the device pin and the pad, improving the utilization rate of the solder paste, ensuring the strength of the solder joint, thereby improving the quality and reliability of the soldering, and preventing poor soldering such as offset, cold solder joints, and empty solder joints, thereby improving the soldering yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a schematic structural diagram of an embodiment of the present utility model;

[0022] Figure 2 This is a structural diagram of the positional relationship between the parallel opening and the pad in one embodiment of the present invention;

[0023] Figure 3 This is a structural diagram of the positional relationship among the parallel openings, pads, and components in one embodiment of the present invention.

[0024] Among them, the figure marks in the figure are: 1. Parallel opening; 101. A pair of steel mesh openings; 102. Steel mesh opening; 103. First side; 104. Second side; 105. Third side; 106. Fourth side; 107. Chamfer; 108. Rounded corner; 2. Pad; 3. Device. DETAILED DESCRIPTION

[0025] 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 with reference to 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.

[0026] It should be noted that when a component is referred to as being "fixed" or "set" or "connected" to another component, it may be located directly or indirectly on the other component. The directions or positions indicated by the terms "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positions shown in the accompanying drawings and are only for the convenience of description and cannot be understood as limitations on this technical solution. The terms "first", "second", etc. are only used for the convenience of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. "Multiple" means two or more, unless otherwise clearly and specifically defined. "Several" means one or more, unless otherwise clearly and specifically defined.

[0027] like Figures 1 to 3 As shown, a steel mesh structure for improving the welding effect of parallel devices described in one embodiment of the present invention includes a plurality of parallel opening portions 1, and the parallel opening portion 1 includes two pairs of steel mesh openings 102 arranged at intervals. Each parallel opening portion 1 corresponds to a soldering pad 2 on the circuit board, and the device 3 corresponding to each pair of steel mesh openings 102 has a specification smaller than the device 3 corresponding to the soldering pad 2. The soldering pad 2 includes two solder points, and each pair of two steel mesh openings 102 are respectively located on the two solder points of a soldering pad 2.

[0028] Laser cutting technology can be used in the production of stencil structures. First, a stencil design with parallel openings 1 is created based on the layout of the pads 2 on the circuit board and the requirements for parallel soldering. Subsequently, a laser cutter is used to precisely cut the stainless steel sheet to form the required stencil openings 102. During this process, cutting accuracy is strictly controlled to ensure that the size and position of each stencil opening 102 meet the design requirements. Stencil structures produced using laser cutting are not only highly precise but also highly efficient, meeting the needs of large-scale production.

[0029] When in use, first place the steel mesh accurately on the circuit board to ensure that each parallel opening 1 is aligned with the corresponding pad 2. Then, use the solder paste printing equipment to print the solder paste through the opening on the steel mesh onto the pad 2 of the circuit board. Then, use the SMT (surface mount technology) equipment to place the device 3 on the solder paste. Since the specifications of the device 3 corresponding to a pair of steel mesh openings 101 are smaller than the specifications of the device 3 corresponding to the pad 2, such as the steel mesh opening 102 corresponds to a device 3 of 0201 specifications, and the pad 2 corresponds to a device 3 of 0402 specifications, it can be ensured that two small-sized devices 3 are accurately placed on one pad 2. Finally, the device 3 is firmly connected to the pad 2 by the wave soldering equipment. Using this steel mesh structure, precise soldering of parallel devices 3 can be easily achieved, collisions and interference between devices 3 can be avoided, and welding quality and product performance can be improved.

[0030] This embodiment ensures the accurate positioning and stable mounting of the device 3 during the welding process by precisely controlling the size and position of the steel mesh opening 102, and accurately places two small-sized devices 3 (such as 0201) on a large-sized pad 2 (such as 0402), thereby achieving the precise placement of the device 3 on the pad 2. The four steel mesh openings 102 corresponding to the two parallel devices 3 are independent of each other, preventing the device 3 from generating large tension or traction during the welding process, preventing collisions and interference between the devices 3, and achieving parallel welding of the devices 3 without changing the original pad 2 design. At the same time, it avoids the cost loss of re-boarding due to board design problems, and ensures the quality and reliability of the product. In addition, the steel mesh structure also improves the accuracy and stability of welding, which significantly improves the welding quality.

[0031] In actual application, the number of the steel mesh openings 102 is set according to the specific product performance requirements to ensure that two devices 3 can be welded in parallel on the pads 2 with corresponding position numbers.

[0032] like Figure 1 As shown, in a preferred embodiment, the two pairs of steel meshes are symmetrically arranged about the horizontal line, and the horizontal center line and the vertical center line of the parallel opening 1 are collinear with the horizontal center line and the vertical center line of the pad 2 respectively.

[0033] In this embodiment, due to the good alignment between the parallel opening portion 1 and the pad 2, the solder paste can be accurately printed on the pad 2, reducing the offset of the solder paste. The position setting of the parallel opening portion 1 can ensure the precise positioning of the device 3 during the welding process, thereby preventing potential problems such as poor welding and short circuits, improving the accuracy of welding, and effectively avoiding mutual collision and interference between the devices 3, thereby ensuring the quality of welding and the stability of the electrical connection and mechanical connection of the welding point. Since the solder paste is accurately printed on the pad 2, the connection between the device 3 and the pad 2 is more secure during welding, reducing the risk of welding failure, reducing the rework rate and defective rate caused by welding problems, improving production efficiency, and saving costs. In addition, the symmetrical design of the steel mesh structure enhances its stability and reliability in application, so that the steel mesh can be evenly stressed during use, reducing the possibility of deformation or damage caused by uneven stress, thereby extending the service life of the steel mesh.

[0034] like Figure 1 and Figure 2 As shown, in a preferred embodiment, the side of the two pairs of steel mesh openings 102 away from each other is the first side 103, the side opposite to the first side 103 is the second side 104, the side adjacent to the left side of the first side 103 is the third side 105, and the side adjacent to the right side of the first side 103 is the fourth side 106. The first side 103 extends beyond the edge of the weld point, so that there is sufficient spacing between the two pairs of steel mesh openings 102.

[0035] In this embodiment, in order to ensure the independence and accuracy of the solder paste printing of each solder joint and to ensure that there is enough solder paste on the solder joint to solder the device 3, the steel mesh opening 102 is offset a certain distance to the outside of the pad 2. The offset distance is less than half the length of the third side 105. On the one hand, it prevents the devices 3 from interfering with or colliding with each other during the soldering process. On the other hand, it ensures that there is a sufficiently large contact surface between the solder paste and the pad 2 to ensure the soldering quality. Specifically, when two 0201-sized devices 3 are soldered in parallel on a 0402-sized pad 2, the steel mesh opening 102 is square, that is, the length of the first side 103, the second side 104, the third side 105, and the fourth side 106 of the steel mesh opening 102 are equal, that is, the length is 0.3 mm. In actual applications, steel mesh openings 102 of other shapes such as rectangles can be used.

[0036] like Figure 1 and Figure 2 As shown, in a preferred embodiment, the first side 103 and the adjacent side are both provided with chamfers 107. During the reflow soldering process, the solder paste moves closer to the inner side of the solder pad 2 to ensure soldering quality.

[0037] The horizontal length A of the chamfer 107 is 1 / 4 to 1 / 2 of the length of the first side 103. Preferably, the horizontal length A of the chamfer 107 is 1 / 3 of the length of the first side 103. Specifically, when the pair of stencil openings 102 is used to weld a 0201 device 3, and the length of the first side 103 is 0.3 mm, the horizontal length A of the chamfer 107 is 0.1 mm.

[0038] The vertical length B of the chamfer 107 is 1 / 4 to 1 / 2 of the length of the third side 105. Preferably, the vertical length B of the chamfer 107 is 1 / 3 of the length of the third side 105. Specifically, when the pair of stencil openings 102 is used to weld a 0201 device 3, and the length of the third side 105 is 0.3 mm, the vertical length B of the chamfer 107 is 0.1 mm.

[0039] The horizontal length A of the chamfer 107 is equal to the vertical length B, that is, the chamfer 107 is 45°.

[0040] When solder paste is printed onto pad 2 using a stencil, chamfer 107 reduces the amount of solder paste distributed beyond pad 2, ensuring that the majority of the solder paste resides on pad 2. During reflow, as the temperature rises, the solder paste begins to melt and flow. The molten solder paste naturally converges. Since the solder paste area inside pad 2 is larger, the solder outside pad 2 converges inside, filling the gap between the pin of device 3 and pad 2, thus forming a good solder joint.

[0041] In this embodiment, by providing chamfers 107 on the steel mesh openings 102, most of the solder paste can be accurately placed on the pads 2, reducing unnecessary distribution of the solder paste on the outside of the pads 2. In addition, a sufficiently large area of ​​solder paste is provided on the pads 2, so that when the device 3 is mounted, the device 3 can be placed stably on the solder paste. During the reflow process, as the solder paste melts and flows, the less solder paste on the outside of the pads 2 will naturally converge to the inside of the pads 2, effectively filling the gap between the pins of the device 3 and the pads 2, thereby improving the utilization rate of the solder paste and ensuring the strength of the solder joints, thereby improving the quality and reliability of the soldering, and preventing poor soldering such as offset, cold solder joints, and empty solder joints, thereby improving the soldering yield.

[0042] like Figure 1 As shown, in a preferred embodiment, the first side 103 , the second side 104 , the third side 105 and the fourth side 106 are all provided with rounded corners 108 between adjacent sides.

[0043] The radius of the fillet 108 is 1 / 7 to 1 / 5 of the length of the first side 103. Preferably, the radius of the fillet 108 is 1 / 6 of the length of the first side 103. Specifically, when the pair of stencil openings 102 are used to weld a 0201 device 3, the length of the first side 103 is 0.3 mm, and the radius of the fillet 108 is 0.05 mm.

[0044] When solder paste is printed onto pad 2 through the stencil, rounded corners 108 reduce solder paste accumulation and adhesion at the edges, allowing for smoother separation from the stencil. This is because rounded corners 108 reduce edge sharpness, reducing resistance and friction of the solder paste at the corners of stencil opening 102, thus facilitating smooth solder paste release. Rounded corners 108 also prevent tearing or stretching of the solder paste during the separation process, ensuring complete and uniform printing.

[0045] In this embodiment, rounded corners 108 are provided between each edge and adjacent edges to improve the quality and efficiency of solder paste printing. These rounded corners not only facilitate smoother separation of the solder paste from the stencil, reducing solder paste accumulation and waste at the edges, but also enhance printing uniformity and consistency. Furthermore, these rounded corners reduce friction between the stencil and the solder paste, minimizing the risk of damage and deformation during the printing process, ensuring high-quality solder paste printing and, consequently, soldering quality.

[0046] like Figure 1 As shown, in a preferred embodiment, the spacing C between the two pairs of stencil openings is 0.3 to 0.5 times the length of the third side 105. Preferably, the spacing C between the two pairs of stencil openings is 0.4 times the length of the third side 105. Specifically, when the pair of stencil openings 102 is used to weld a 0201 device 3, the length of the third side 105 is 0.3 mm, and the spacing C between the two pairs of stencil openings is 0.12 mm.

[0047] In this embodiment, the spacing C between the two pairs of steel mesh openings is determined based on a specific ratio of the length of the third side 105. When the solder paste is printed onto the pad 2 through the steel mesh, the distance C between each pair of steel mesh openings needs to be moderate to ensure that the solder paste can accurately cover the pins of each device 3, and will not cause loose welding due to excessive spacing, nor will it cause large tension or traction during the furnace process due to too small spacing, causing the device 3 to collide.

[0048] This embodiment precisely controls the spacing C between the two pairs of stencil openings, allowing the solder paste to accurately cover the pins of each component 3, thus avoiding short circuits or cold solder joints. Furthermore, the two parallel components 3 remain relatively independent, minimizing any mutual influence during soldering and ensuring that the two components 3 can be soldered in parallel to the same pad 2.

[0049] like Figure 1As shown, in a preferred embodiment, the spacing D between each pair of two stencil openings is 0.7 to 0.9 times the length of the first side 103 to prevent soldering. Preferably, the spacing D between each pair of two stencil openings is 0.783 times the length of the first side 103. Specifically, when the pair of stencil openings 102 is used to solder a 0201 device 3, and the length of the first side 103 is 0.3 mm, the spacing D between each pair of two stencil openings is 0.235 mm.

[0050] In this embodiment, the spacing D between each pair of stencil openings 102 is set to 0.7 to 0.9 times the length of the first side 103 to prevent solder bridging during the soldering process. Bridging occurs when the solder paste between adjacent solder joints connects when molten, leading to a short circuit or reduced soldering quality. By precisely controlling the spacing D between each pair of stencil openings 102, the solder paste does not contact each other when molten, thus preventing bridging.

[0051] This embodiment effectively prevents solder bridging by precisely setting the spacing D between each pair of stencil openings 102, improving soldering stability and reliability and ensuring proper circuit operation. Furthermore, this technology reduces the rework and scrap rates caused by solder bridging, improving production efficiency and saving costs.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A steel mesh structure for improving the welding effect of parallel devices, characterized in that: It includes a plurality of parallel opening parts, each of which includes two pairs of steel mesh openings arranged at intervals, each of the parallel opening parts corresponds to a soldering pad on the circuit board, the device specification corresponding to each pair of the steel mesh openings is smaller than the device specification corresponding to the soldering pad, the soldering pad includes two soldering points, and each pair of two steel mesh openings are respectively located on the two soldering points of a soldering pad.

2. A steel mesh structure for improving the welding effect of parallel devices according to claim 1, characterized in that: The two pairs of steel meshes are symmetrically arranged about a horizontal line, and the horizontal center line and the vertical center line of the parallel openings are collinear with the horizontal center line and the vertical center line of the welding pad, respectively.

3. A steel mesh structure for improving the welding effect of parallel devices according to claim 2, characterized in that: The side of the two pairs of steel mesh openings away from each other is the first side, the side opposite to the first side is the second side, the side adjacent to the left side of the first side is the third side, the side adjacent to the right side of the first side is the fourth side, and the first side exceeds the edge of the welding point.

4. A steel mesh structure for improving the welding effect of parallel devices according to claim 3, characterized in that: The first side and adjacent sides are both provided with chamfers.

5. A steel mesh structure for improving the welding effect of parallel devices according to claim 4, characterized in that: The length of the chamfer in the horizontal direction is 1 / 4 to 1 / 2 of the length of the first side, and the length of the chamfer in the vertical direction is 1 / 4 to 1 / 2 of the length of the third side.

6. A steel mesh structure for improving the welding effect of parallel devices according to any one of claims 4-5, characterized in that: The length of the chamfer in the horizontal direction is equal to the length in the vertical direction.

7. A steel mesh structure for improving the welding effect of parallel devices according to claim 3, characterized in that: The first side, the second side, the third side and the fourth side are all provided with rounded corners between adjacent sides.

8. A steel mesh structure for improving the welding effect of parallel devices according to claim 7, characterized in that: The radius of the rounded corner is 1 / 7 to 1 / 5 of the length of the first side.

9. A steel mesh structure for improving the welding effect of parallel devices according to claim 3, characterized in that: The spacing between the two pairs of steel mesh openings is 0.3 to 0.5 times the length of the third side.

10. A steel mesh structure for improving the welding effect of parallel devices according to claim 3, characterized in that: The spacing between each pair of two steel mesh openings is 0.7 to 0.9 times the length of the first side.

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