Steel mesh

Abstract

The utility model belongs to the technical field of welding, and provides a steel mesh which comprises a first plate body, a plurality of hole sets are formed in the first plate body, the multiple hole sets are sequentially arranged in a surrounding mode from the center of the first plate body to the edge of the first plate body, and each hole set comprises a plurality of center through holes with the same hole diameter; in the direction from the center of the first board body to the edge of the first board body, the hole diameter of the central through hole of each hole group is gradually increased, the hole edge spacing of each hole group is gradually reduced, and the plurality of hole groups are used for solder to be printed on a central bonding pad of the printed circuit board. When the welding flux is printed on the bonding pad through the steel mesh, the welding flux can be evenly distributed on the bonding pad, gas generated when the welding flux is melted can be easily exhausted, the welding firmness is good, and the welding quality can be improved.

Description

Technical Field

[0001] The present application relates to the field of welding technology, and in particular to a steel mesh. Background Art

[0002] In the related art, a steel mesh is usually used to print solder such as tin paste on the pad of a printed circuit board. The steel mesh is usually provided with a single solder hole whose size is similar to that of the pad. The solder hole is used to allow the solder to leak onto the pad. When the solder is printed on the pad using the above-mentioned steel mesh, the solder is prone to uneven distribution on the pad, and the bubbles generated when the solder melts cannot be effectively discharged, which easily leads to poor soldering quality. Utility Model Content

[0003] The purpose of the embodiments of the present application is to provide a steel mesh to solve the technical problem in the prior art that when the steel mesh is used for solder printed on a pad, the soldering quality of the solder is poor.

[0004] To achieve the above purpose, the technical solution adopted in this application is: to provide a steel mesh, including:

[0005] The steel mesh includes a first plate body, on which a plurality of hole groups are provided. The plurality of hole groups are arranged in sequence from the center of the first plate body to the edge of the first plate body, and each of the hole groups includes a plurality of central through holes with the same aperture. In the direction from the center of the first plate body to the edge of the first plate body, the aperture of the central through hole of each hole group gradually increases, and the spacing between the hole edges of each hole group gradually decreases. The plurality of hole groups are used for allowing solder to be leak-printed onto the central pad of a printed circuit board.

[0006] In some embodiments, the diameter of each of the central through holes is 0.25 mm-0.4 mm.

[0007] In some embodiments, the distance between the centers of every two adjacent central through holes in the same hole group is 0.5 mm-0.8 mm.

[0008] In some embodiments, for two adjacent hole groups, the difference between the diameter of the central through hole of the hole group close to the edge of the first plate body and the diameter of the central through hole of the hole group close to the center of the first plate body is equal to 0.05mm-0.1mm.

[0009] In some embodiments, the central through hole is a circular hole, an elliptical hole or a polygonal hole.

[0010] In some embodiments, the plurality of central through holes surrounding the central hole on the central pad are all circular holes.

[0011] In some embodiments, the center distance between each two adjacent central through holes on the first plate body is equal to a predetermined value.

[0012] In some embodiments, the hole group includes a first hole group and a second hole group, the first hole group includes a plurality of first holes arranged in a rectangular array, the aperture of the first holes is 0.25 mm, and the spacing between the centers of each two adjacent first holes is 0.5 mm-0.6 mm; the second hole group includes a plurality of second holes arranged in a ring-shaped grid array, the plurality of second holes are arranged on the outside of the plurality of first holes, the aperture of the second holes is 0.3 mm, and the spacing between the centers of each two adjacent second holes is 0.55 mm-0.65 mm.

[0013] In some embodiments, the hole group includes a third hole group, and the third hole group includes a plurality of third holes arranged in a ring-shaped grid array, and the plurality of third holes are arranged on the outside of the plurality of second holes. The aperture of the third holes is 0.35 mm, and the distance between the centers of each two adjacent third holes is 0.6 mm-0.7 mm.

[0014] In some embodiments, the steel mesh also includes a second plate body, which is connected to the first plate body and surrounds the outer side of the first plate body. The first plate body is provided with a plurality of edge through holes, and the plurality of edge through holes are arranged around the plurality of hole groups. The plurality of edge through holes are used for allowing solder to be leaked onto the edge pads of the printed circuit board.

[0015] The beneficial effect of the steel mesh provided by the present application is that, compared with the prior art, the steel mesh provided by the present application has a plurality of hole groups on its first plate body, and the plurality of hole groups are arranged in sequence from the center of the first plate body to the edge of the first plate body, each hole group includes a plurality of central through holes with the same aperture, and in the direction from the center of the first plate body to the edge of the first plate body, the aperture of the central through hole of each hole group gradually increases, and the spacing between the hole edges gradually decreases. With such an arrangement, when the steel mesh provided by the present application is used to print solder on the central pad of the printed circuit board, the area on the central pad corresponding to each central through hole will be printed with solder, and the solder can be printed on the central pad more Evenly distributed, and the welding surface can be kept relatively flat; and, a larger exhaust gap can be formed between the central through holes located in the center of the first plate body, and the bubbles generated by the melting of the solder can be easily discharged through the central hole on the central pad, and the aperture of the central through hole located at the edge of the first plate body is larger, which can form a larger exhaust gap while ensuring that a sufficient amount of solder is printed on the central pad, thereby ensuring the firmness of the welding as much as possible. It can be seen that when printing solder through the steel screen provided by the present application, the solder can be more evenly distributed on the central pad, the gas generated when the solder melts is easier to discharge, and the welding firmness is also high, and the overall welding quality is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0017] Figure 1 A schematic diagram of the structure of a central pad printed with solder provided in some embodiments of the present application;

[0018] Figure 2 A schematic diagram of the structure of a steel mesh provided in some embodiments of the present application;

[0019] Figure 3 A schematic diagram of the structure of a steel mesh provided in some embodiments of the present application;

[0020] Figure 4 A schematic diagram of the structure of a steel mesh provided in some embodiments of the present application;

[0021] Figure 5 for Figure 4 A partial enlarged view of point A of the steel mesh shown.

[0022] Among them, the reference numerals in the figure are:

[0023] 1- center pad; 2- center hole; 3- solder;

[0024] 10-Steel mesh;

[0025] 100-first plate; 110-hole group; 110a-first hole group; 1111-first hole; 110b-second hole group; 1112-second hole; 110c-third hole group; 1113-third hole; 111-center through hole;

[0026] 200 - second plate body; 210 - edge through hole. DETAILED DESCRIPTION

[0027] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0028] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present application 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 operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0029] 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0030] Reference throughout the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, when the phrases "in one embodiment" or "in some embodiments" appear in various places throughout the specification, not all references are to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner.

[0031] In the related art, a steel mesh is usually used to print solder such as tin paste on the pad of a printed circuit board. The steel mesh is usually provided with a single solder hole whose size is similar to that of the pad. The solder hole is used to allow the solder to leak onto the pad. When the solder is printed on the pad using the above-mentioned steel mesh, the solder is prone to uneven distribution on the pad, and the bubbles generated when the solder melts cannot be effectively discharged, which easily leads to poor soldering quality.

[0032] To solve the above problems, please refer to Figure 1 and Figure 2 The embodiment of the present application provides a steel mesh 10. When the solder 3 is printed on the center pad 1 of the steel mesh 10, the solder 3 can be distributed more evenly on the center pad 1 of the printed circuit board, the bubbles generated when the solder 3 melts are easier to discharge and the welding firmness is better, and the overall welding performance of the printed solder 3 is better.

[0033] See also Figure 2The steel mesh 10 provided in the embodiment of the present application includes a first plate body 100, and a plurality of hole groups 110 are provided on the first plate body 100. The plurality of hole groups 110 are sequentially arranged from the center of the first plate body 100 to the edge of the first plate body 100. Each hole group 110 includes a plurality of central through holes 111 with the same aperture. In the direction from the center of the first plate body 100 to the edge of the first plate body 100, the aperture of the central through hole 111 of each hole group 110 gradually increases, and the hole edge spacing D1 of each hole group 110 gradually decreases. The plurality of hole groups 110 are used for allowing solder 3 to be leak-printed onto the central pad 1 of the printed circuit board.

[0034] Specifically, the shape of the first plate body 100 can be circular, elliptical or polygonal, and can be set according to the shape of the central pad 1 on the printed circuit board. Figures 1 to 3 In the illustrated embodiment, the first plate body 100 is in a square shape.

[0035] It should be noted that the multiple hole groups 110 are arranged in sequence from the center of the first plate body 100 to the edge of the first plate body 100. It can be understood that one of the multiple hole groups 110 is arranged at the center of the first plate body 100, and the other hole groups 110 in the multiple hole groups 110 are arranged in sequence from the inside to the outside of the first plate body 100 on the outside of the hole group 110 located at the center of the first plate body 100.

[0036] Specifically, each hole group 110 can be arranged on the first plate body 100 in different ways. For example, the central through holes 111 of each hole group 110 can be arranged in a circular ring shape, and multiple hole groups 110 arranged in a circular ring shape can be concentrically arranged. For another example, there are two hole groups 110, one of which is arranged at the center of the first plate body 100, and all the central through holes 111 of the hole group 110 are arranged in a rectangular array, and a part of the central through holes 111 of the other hole group 110 are arranged on one side of the hole group 110 located at the center of the first plate body 100, and another part of the central through holes 111 of the other hole group 110 are arranged on the other side of the hole group 110 located at the center of the first plate body 100. When the solder 3 is printed on the printed circuit board using the steel mesh 10 with the above structure, the structure schematic diagram of the solder 3 formed by printing is as shown in FIG. Figure 1 Of course, the hole groups 110 can also be arranged on the first plate body 100 in other ways, and can be set as needed.

[0037] It should also be noted that the hole edge spacing D1 of the hole group 110 refers to the minimum spacing between the hole edges of two adjacent center through holes 111 in the hole group 110. Since the apertures of the center through holes 111 in the same hole group 110 are all equal, for the two center through holes 111 in the same hole group 110, the hole edge spacing is equal to the distance D2 between the centers of the two center through holes 111 minus the aperture of one center through hole 111.

[0038] Specifically, the central through hole 111 can be a circular hole, an elliptical hole, a polygonal hole or a quasi-circular hole, and can be set as needed. When the central through hole 111 is set as a circular hole, the aperture of the central through hole 111 refers to the diameter of the circular hole. When the central through hole 111 is set as a square hole, the aperture of the central through hole 111 refers to the side length of the square hole. When the central through hole 111 is set as an elliptical hole, the aperture of the central through hole 111 can include the major axis length and the minor axis length of the elliptical hole. For example, refer to Figure 5 , the central through hole 111 is a regular octagon.

[0039] The steel mesh 10 provided in the present embodiment has a plurality of hole groups 110 on its first plate body 100, and the plurality of hole groups 110 are arranged in sequence from the center of the first plate body 100 to the edge of the first plate body 100, and each hole group 110 includes a plurality of central through holes 111 with the same aperture, and in the direction from the center of the first plate body 100 to the edge of the first plate body 100, the aperture of the central through hole 111 of each hole group 110 gradually increases, and the spacing between the hole edges gradually decreases. With such an arrangement, when the steel mesh 10 provided in the present application is used to print solder 3 on the central pad 1 of the printed circuit board, the area on the central pad 1 corresponding to each central through hole 111 will be printed with solder 3, and the solder 3 can be distributed more evenly on the central pad 1. cloth, and the welding surface can be kept relatively flat; and, the hole edge spacing D1 of the central through hole 111 located at the center of the first plate body 100 is relatively large, which can form a larger exhaust gap, so that the bubbles generated by the melting of the solder 3 are discharged through the central hole 2 on the central pad 1, and the aperture of the central through hole 111 located at the edge of the first plate body 100 is relatively large, which can form a larger exhaust gap while ensuring that a sufficient amount of solder 3 is printed on the central pad 1, and the firmness of the welding is guaranteed as much as possible. It can be seen that when the solder 3 is printed through the steel mesh 10 provided in this embodiment, the solder 3 can be more evenly distributed on the central pad 1, the gas generated when the solder 3 is melted is easier to discharge, and the welding firmness is also high, and the overall welding quality is good.

[0040] The steel mesh 10 provided in this embodiment is particularly suitable for a center ground pad with an area greater than 3 mm×3 mm that adopts a QFN (Quad Flat No-leads) packaging or a module level packaging (Module Level Packaging) process.

[0041] In some embodiments, the diameter of each central through hole 111 is 0.25 mm-0.4 mm, for example, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, etc.

[0042] In the technical solution provided in the embodiment of the present application, the aperture value of each center through hole 111 is relatively appropriate, which can minimize the solder 3 being raised or bulged due to the center through hole 111 being too large, so that the welding surface can remain flat. It can also minimize the situation where the solder 3 cannot be put in or the solder 3 blocks the center through hole 111 due to the center through hole 111 being too small, which is beneficial for the solder 3 to be distributed more evenly on the center pad 1 and is beneficial for maintaining the flatness of the welding surface.

[0043] In some embodiments, the distance between the centers of every two adjacent central through holes 111 in the same hole group 110 is 0.5 mm-0.8 mm. For example, 0.6 mm, 0.7 mm, 0.8 mm, etc. This arrangement can make the ratio of the sum of the areas of all the central through holes 111 on the first board 100 to the total area of ​​the first board 100 more appropriate, and thus can make the ratio of the area of ​​the area printed with solder 3 on the central pad 1 to the total area of ​​the central pad 1 reach an appropriate value, thereby ensuring the reliability of welding.

[0044] In some embodiments, for two adjacent hole groups 110, the difference between the aperture of the central through hole 111 of the hole group 110 close to the edge of the first board 100 and the aperture of the central through hole 111 of the hole group 110 close to the center of the first board 100 is equal to 0.05mm-0.1mm. In this way, the aperture difference of the central through hole 111 on the first board 100 will not be too large, which is conducive to the more uniform distribution of the solder 3 on the central pad 1, and the aperture difference of the central through hole 111 will not be too small, which is convenient for forming an exhaust space at the center of the first board 100, and printing more solder 3 at the edge of the first board 100.

[0045] In some embodiments, the plurality of central through holes 111 surrounding the central hole 2 on the central pad 1 are all circular holes.

[0046] It can be understood that a center hole 2 is provided on the center pad 1 of the printed circuit board, and the center hole 2 can discharge at least a part of the gas generated when the solder 3 melts, so the center through hole 111 on the first board body 100 needs to avoid the center hole 2 on the center pad 1.

[0047] In the technical solution provided in this embodiment, the multiple central through holes 111 surrounding the central hole 2 are all set to be circular. The edges of the circular central through holes 111 are smooth, making it easier to avoid the central hole 2, and the arrangement of the central through holes 111 on the first plate body 100 can be more flexible.

[0048] In some embodiments, the center distance between each two adjacent central through holes 111 on the first plate body 100 is equal to a predetermined value. The predetermined value may be 0.25 mm, 0.3 mm, etc. In this way, the distance between any two adjacent central through holes 111 on the first plate body 100 is equal, which can simplify the processing technology of the first plate body 100 and facilitate the preparation of the first plate body 100.

[0049] See also Figure 3 In some embodiments, the hole group 110 includes a first hole group 110a and a second hole group 110b, the first hole group 110a includes a plurality of first holes 1111 arranged in a rectangular array, the aperture of the first holes 1111 is 0.25 mm, and the spacing D21 between the centers of each two adjacent first holes 1111 is 0.5 mm-0.6 mm; the second hole group 110b includes a plurality of second holes 1112 arranged in a ring-shaped grid array, the plurality of second holes 1112 are arranged outside the plurality of first holes 1111, the aperture of the second holes 1112 is 0.3 mm, and the spacing D22 between the centers of each two adjacent second holes 1112 is 0.55 mm-0.65 mm.

[0050] Specifically, the distance D21 between the centers of every two adjacent first holes 1111 may be 0.55 mm; and the distance D22 between the centers of every two adjacent second holes 1112 may be 0.56 mm.

[0051] In the technical solution provided in this embodiment, compared with the hole edge spacing D12 of the second hole group 110b located at the edge of the first plate body 100, the hole edge spacing D11 of the first hole group 110a located at the center of the first plate body 100 is larger, which can form a larger exhaust gap in the central area of ​​the first plate body 100, so that the bubbles generated by the melting of the solder 3 can be more easily discharged through the central hole 2 on the central pad 1, and the aperture of the second hole 1112 of the second hole group 110b located at the edge of the first plate body 100 is larger, which can form a larger exhaust gap at the center position of the first plate body 100 while ensuring that a sufficient amount of solder 3 is printed on the central pad 1, thereby ensuring the firmness of the welding as much as possible and making the overall welding performance of the printed solder 3 better.

[0052] See also Figure 4 In some embodiments, the hole group 110 includes a third hole group 110c, the third hole group 110c includes a plurality of third holes 1113 arranged in a ring-shaped grid array, the plurality of third holes 1113 are arranged on the outside of the plurality of second holes 1112, the aperture of the third holes 1113 is 0.35 mm, and the distance D23 between the centers of each two adjacent third holes 1113 is 0.6 mm-0.7 mm.

[0053] Specifically, the spacing D23 between the centers of the third holes 1113 is 0.6 mm.

[0054] In the technical solution provided in this embodiment, compared with the hole edge spacing D12 of the second hole group 110b located at the edge of the first plate body 100 and the hole edge spacing D13 of the third hole group 110c, the hole edge spacing D11 of the first hole group 110a located at the center of the first plate body 100 is larger, which can form a larger exhaust gap, so that the bubbles generated by the melting of the solder 3 can be more easily discharged through the center hole 2 on the center pad 1, and the second hole 1112 and the third hole 1113 located outside the first hole 1111 have larger apertures, which can form a larger exhaust gap at the center position of the first plate body 100 while ensuring that a sufficient amount of solder 3 is printed on the center pad 1, thereby ensuring the firmness of the welding as much as possible and making the overall welding performance of the printed solder 3 better.

[0055] Furthermore, in the technical solution provided in this embodiment, the use of the hole group 110 with three hole edge spacings gradually changing is more conducive to the bubbles generated when the solder 3 melts gradually gathering to the center hole 2 of the center pad 1 and being discharged from the center hole 2.

[0056] See also Figure 5 In some embodiments, the steel mesh 10 also includes a second plate body 200, which is connected to the first plate body 100 and surrounds the outer side of the first plate body 100. The first plate body 100 is provided with a plurality of edge through holes 210, and the plurality of edge through holes 210 are arranged around the plurality of hole groups 110. The plurality of edge through holes 210 are used for allowing the solder 3 to be leaked onto the edge pads of the printed circuit board.

[0057] Specifically, the second plate body 200 is a ring-shaped structure, and the shape of the inner contour of the second plate body 200 is the same as the shape of the outer contour of the first plate body 100. Figures 2 to 4 In the illustrated embodiment, the first plate bodies 100 are all square, the second plate bodies 200 are all square rings, and the edge through holes 210 are respectively arranged on four sides of the second plate bodies 200 .

[0058] In the technical solution provided in the embodiment of the present application, the solder 3 can be printed on the central pad 1 and the edge pad of the printed circuit board at the same time, thereby improving the printing efficiency of the solder 3.

[0059] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A steel mesh, characterized in that: The steel mesh includes a first plate body, on which a plurality of hole groups are provided. The plurality of hole groups are arranged in sequence from the center of the first plate body to the edge of the first plate body, and each of the hole groups includes a plurality of central through holes with the same aperture. In the direction from the center of the first plate body to the edge of the first plate body, the aperture of the central through hole of each hole group gradually increases, and the spacing between the hole edges of each hole group gradually decreases. The plurality of hole groups are used for allowing solder to be leak-printed onto the central pad of a printed circuit board.

2. The steel mesh according to claim 1, characterized in that: The diameter of each central through hole is 0.25mm-0.4mm.

3. The steel mesh according to claim 2, characterized in that: The distance between the centers of every two adjacent central through holes in the same hole group is 0.5 mm-0.8 mm.

4. The steel mesh according to claim 1, characterized in that: For two adjacent hole groups, the difference between the diameter of the central through hole of the hole group close to the edge of the first plate body and the diameter of the central through hole of the hole group close to the center of the first plate body is equal to 0.05mm-0.1mm.

5. The steel mesh according to claim 1, characterized in that: The central through hole is a circular hole, an elliptical hole or a polygonal hole.

6. The steel mesh according to claim 5, characterized in that: The plurality of central through holes surrounding the central hole on the central pad are all circular holes.

7. The steel mesh according to claim 1, characterized in that: The center distance between each two adjacent central through holes on the first plate body is equal to a predetermined value.

8. The steel mesh according to claim 1, characterized in that: The hole group includes a first hole group and a second hole group, the first hole group includes a plurality of first holes arranged in a rectangular array, the aperture of the first holes is 0.25 mm, and the spacing between the centers of each two adjacent first holes is 0.5 mm-0.6 mm; the second hole group includes a plurality of second holes arranged in a ring-shaped grid array, the plurality of second holes are arranged on the outside of the plurality of first holes, the aperture of the second holes is 0.3 mm, and the spacing between the centers of each two adjacent second holes is 0.55 mm-0.65 mm.

9. The steel mesh according to claim 8, characterized in that: The hole group includes a third hole group, which includes a plurality of third holes arranged in a ring-shaped grid array, wherein the plurality of third holes are arranged outside the plurality of second holes, the aperture of the third holes is 0.35 mm, and the distance between the centers of each two adjacent third holes is 0.6 mm-0.7 mm.

10. The steel mesh according to any one of claims 1 to 9, characterized in that: The steel mesh also includes a second plate body, which is connected to the first plate body and surrounds the outer side of the first plate body. The first plate body is provided with a plurality of edge through holes, and the plurality of edge through holes are arranged around the plurality of hole groups. The plurality of edge through holes are used for allowing solder to be leaked onto the edge pads of the printed circuit board.

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