Preforming soldering lug

Abstract

The utility model discloses a preformed soldering lug which comprises a main soldering lug, the bottom of the main soldering lug is a soldering surface, the central area of the bottom of the main soldering lug is the soldering lug center, the edge areas of the two sides of the main soldering lug are soldering lug edges, the thickness of the soldering lug center is larger than that of the soldering lug edges, and continuous transition is formed between the soldering lug center and the soldering lug edges. A plurality of exhaust holes penetrating vertically are formed in the two sides of the main soldering lug along the central axis, an auxiliary soldering lug is further welded to the top of the main soldering lug, in the melting collapse process, redundant gas between the main soldering lug and an object part can be directly exhausted through the exhaust holes, on one hand, the heating time of the temperature gradient can be prolonged through indirect partition of the exhaust holes, and on the other hand, the temperature gradient is increased; on the one hand, the hot melting speed is reduced, the main soldering lug collapses from the center to the two sides more linearly, air is extruded and exhausted more thoroughly, on the other hand, air which is not exhausted can be effectively exhausted through the exhaust holes, and therefore the void rate in the welding process is greatly reduced, and the welding quality is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of brazing materials, in particular to a preformed welding sheet. Background Art

[0002] Solder sheet is a thin sheet cast from metals such as silver, copper, and zinc, usually rolled into about twenty wires, mainly used for welding various small metals, and has the characteristics of high welding regular strength. Solder sheet has a wide range of applications and can be used for brazing methods such as gas flame, high frequency, resistance, and furnace, as well as playing an important role in the type packaging process. In actual applications, when the solder is at the brazing temperature, the liquid solder wets and expands, and its front edge advances. Since the solder sheet usually has a high edge temperature and a low center temperature, the solder melts first at the outer edge and then develops toward the center, causing the gas in the center to be enclosed in the center of the pad by the liquid solder on the outside and unable to escape, and eventually evolves into a void.

[0003] The patent document with announcement number CN207239482U discloses a preformed solder sheet, which controls the shape of the preformed solder sheet so that the center thickness is thicker than the edge thickness. During assembly, the force points of the solder sheet are concentrated in the middle, which reduces the thermal resistance, while a gap is formed between the edge and the object to be welded, increasing the thermal resistance and forming a temperature gradient with high temperature in the middle and low temperature at the edge. The solder sheet starts to melt from the center during welding, effectively removing gas, thereby reducing the void rate during welding.

[0004] The above technical solution still has some shortcomings in practical application. Since the welding piece is usually relatively thin, during resistance welding, although in theory a temperature gradient with high temperature in the middle and low temperature at the edge will be formed, so that the welding piece will melt from the center and expel gas during welding; but the actual situation is that during resistance welding, this thin welding piece will usually collapse instantly in a short time, and the temperature gradient will not change significantly. Therefore, it may still cause the central gas to be blocked by the outer solder, resulting in the gas being unable to escape, and evolving into holes, thereby reducing the welding quality. Utility Model Content

[0005] The purpose of this section is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract of the specification and the name of the utility model of this application to avoid blurring the purpose of this section, the abstract of the specification and the name of the utility model, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0006] Therefore, the purpose of the present invention is to provide a preformed welding sheet to solve the problem that the preformed welding sheet in the prior art mentioned in the above background technology has poor gas removal effect during welding, thereby affecting the welding quality.

[0007] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a preformed welding sheet, comprising a main welding sheet, the bottom of the main welding sheet is a welding surface, the bottom center area of ​​the main welding sheet is the welding sheet center and the edge areas on both sides are welding sheet edges, the thickness of the welding sheet center is greater than the thickness of the welding sheet edge, and there is a continuous transition between the welding sheet center and the welding sheet edge, a plurality of exhaust holes that pass through up and down are arranged on both sides of the central axis of the main welding sheet, and an auxiliary welding sheet is also welded on the top of the main welding sheet.

[0008] As a preferred solution of a preformed solder sheet described in the utility model, the transition line between the center of the solder sheet and the edge of the solder sheet can be a straight line or an arc line, and the thickness of the center of the solder sheet is at least twice the thickness of the edge of the solder sheet.

[0009] As a preferred solution of a preformed welding sheet described in the utility model, the top of the main welding sheet is a planar structure, and the top of the main welding sheet is surrounded by edge strips, and a limiting groove is formed on the inner side of the edge strips.

[0010] As a preferred solution of a preformed welding sheet described in the utility model, the length and width of the auxiliary welding sheet are smaller than the inner length and width of the edge strip enclosure, and the edges of the auxiliary welding sheet are also surrounded by sloped surfaces.

[0011] As a preferred solution of the preformed welding sheet described in the utility model, the thickness of the auxiliary welding sheet is less than or equal to the thickness of the edge strip enclosure, and the upper and lower surfaces of the auxiliary welding sheet are both planar structures.

[0012] As a preferred solution of the preformed solder sheet described in the utility model, the surfaces of the main solder sheet and the auxiliary solder sheet are coated with flux.

[0013] Compared with the prior art, the beneficial effects of the utility model are as follows: when welding this kind of preformed welding sheet, since the air in the middle area of ​​the main welding sheet is gradually squeezed to the two sides, the purpose of exhausting gas can be achieved. In this process, the large area of ​​excess gas that may exist between the main welding sheet and the object will be directly discharged through the tiny exhaust holes. On the one hand, the indirect partition of several exhaust holes can increase the heating time of the temperature gradient and reduce the hot melting speed, so that the main welding sheet collapses more linearly from the center to the two sides, and the air is squeezed and exhausted more thoroughly; and even if there is gas that is not exhausted, it will be effectively exhausted by the exhaust holes, thereby greatly reducing the void rate during welding and improving the welding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the overall structure of the welding piece of the utility model;

[0015] Figure 2 This is a schematic diagram of the main welding piece structure of the utility model;

[0016] Figure 3 This is a schematic diagram of the side view of the main welding piece of the utility model and the matching structure of the object;

[0017] Figure 4 This is a schematic diagram of the installation cross-sectional structure of the main welding piece and the auxiliary welding piece of the utility model.

[0018] In the figure: 100, main welding piece; 110, welding piece center; 120, welding piece edge; 130, exhaust hole; 140, edge strip enclosure; 200, auxiliary welding piece; 210, slope surface. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below with reference to the accompanying drawings.

[0020] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the implementation of the present invention, for the sake of convenience, the cross-sectional diagram showing the device structure will not be partially enlarged according to the general proportion, and the schematic diagram is only an example, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0021] In order to make the purpose, technical solution and advantages of the present invention more clear, the implementation mode of the present invention will be further described in detail below with reference to the accompanying drawings.

[0022] Figure 1-Figure 4 The schematic diagram of the whole structure of a preformed solder sheet of the utility model is shown. Figure 1-Figure 4 A preformed soldering sheet in this embodiment includes a main soldering sheet 100, the bottom of the main soldering sheet 100 is a soldering surface, the bottom center area of ​​the main soldering sheet 100 is a soldering sheet center 110 and the edge areas on both sides are soldering sheet edges 120, the thickness of the soldering sheet center 110 is greater than the thickness of the soldering sheet edge 120, and there is a continuous transition between the soldering sheet center 110 and the soldering sheet edge 120, a plurality of exhaust holes 130 are arranged on both sides of the central axis of the main soldering sheet 100, and an auxiliary soldering sheet 200 is also welded on the top of the main soldering sheet 100.

[0023] The transition line between the center 110 of the welding piece and the edge 120 of the welding piece can be a straight line or an arc line, and the thickness of the center 110 of the welding piece is at least twice the thickness of the edge 120 of the welding piece. In the present embodiment, the main welding piece 100 has a structure that is thick in the middle and thin on both sides, and has a distinct transition line. In this way, during resistance welding, the center 110 of the welding piece that is heated first will collapse first. Since the temperature transfer has a certain gradient linearity, the center 110 of the main welding piece 100 will gradually collapse toward the edge 120 of the welding piece until the welding piece is completely welded to the surface of the object. In this process, since the air in the middle area of ​​the main welding piece 100 is gradually squeezed to both sides, the purpose of exhausting gas can be achieved. However, since such a thin soldering sheet usually collapses instantly in a short period of time and the temperature gradient does not change significantly, the central gas may still be blocked by the outer solder, making it impossible for the gas to escape. Therefore, in the process of melting and collapse, the excess gas between the main soldering sheet 100 and the object will be directly discharged through the exhaust hole 130. On the one hand, the indirect isolation of several exhaust holes 130 can increase the heating time of the temperature gradient and reduce the hot melting speed, so that the main soldering sheet 100 collapses more linearly from the center to both sides, and the air is squeezed and discharged more thoroughly. On the other hand, even if there is gas that has not been discharged, it will be effectively discharged by the exhaust hole 130, thereby greatly reducing the void rate during welding and improving the welding quality.

[0024] Since the main welding piece 100 is a micro-hollow structure, in order to further enhance the overall connection strength of the welding piece, here, the top of the main welding piece 100 is a flat structure, and the top of the main welding piece 100 is surrounded by a side strip enclosure 140, and a limiting groove is formed on the inner side of the side strip enclosure 140. The length and width of the auxiliary welding piece 200 are smaller than the inner length and width of the side strip enclosure 140, and the edges of the auxiliary welding piece 200 are also surrounded by a slope surface 210, which makes the edge area of ​​the auxiliary welding piece 200 and the side strip enclosure 140 more tightly after hot melting. The thickness of the auxiliary welding piece 200 is less than or equal to the thickness of the edge strip enclosure 140, and the upper and lower surfaces of the auxiliary welding piece 200 are both planar structures. Here, the auxiliary welding piece 200 only serves as a reinforcement of the main welding piece 100, so the thickness does not need to be too large; specifically, after the welding of the main welding piece 100 is completed, the auxiliary welding piece 200 can be stuck in the limiting groove on the inner side of the edge strip enclosure 140, and then it is subjected to resistance heat melting, so that the auxiliary welding piece 200 is completely welded to the top of the main welding piece 100 and all the exhaust holes 130 are covered. In this way, the contact surface between the main welding piece 100 and the object is free of undesirable voids, and the welding strength is further enhanced; it should be noted that the aperture of the exhaust hole 130 is between about 0.3 and 0.6 mm. Such a small aperture will not have a substantial impact on the strength of the main welding piece 100, and can effectively prevent excess large-area air from accumulating between the welding piece and the object, and the undesirable voids are effectively solved.

[0025] Furthermore, the surfaces of the main soldering sheet 100 and the auxiliary soldering sheet 200 are coated with flux. It can be understood that the flux can effectively improve the thermal melting efficiency and the linearity of the temperature rise gradient of the main soldering sheet 100 and the auxiliary soldering sheet 200.

[0026] Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A solder preform, characterized in that: The invention comprises a main welding piece (100), wherein the bottom of the main welding piece (100) is a welding surface, the center area of ​​the bottom of the main welding piece (100) is a welding piece center (110), and the edge areas on both sides are welding piece edges (120), the thickness of the welding piece center (110) is greater than the thickness of the welding piece edge (120), and there is a continuous transition between the welding piece center (110) and the welding piece edge (120), a plurality of exhaust holes (130) penetrating vertically are arranged on both sides of the central axis of the main welding piece (100), and an auxiliary welding piece (200) is also welded on the top of the main welding piece (100).

2. A solder preform according to claim 1, characterized in that: The transition line between the center (110) of the welding piece and the edge (120) of the welding piece can be a straight line or an arc line, and the thickness of the center (110) of the welding piece is at least twice the thickness of the edge (120) of the welding piece.

3. The solder preform according to claim 1, characterized in that: The top of the main welding piece (100) is a planar structure, and the top of the main welding piece (100) is provided with edge strip enclosures (140) on all four sides, and a limiting groove is formed on the inner side of the edge strip enclosures (140) on all four sides.

4. The solder preform according to claim 1, characterized in that: The length and width of the auxiliary welding piece (200) are smaller than the inner length and width of the edge strip enclosure (140), and the edges of the auxiliary welding piece (200) are also provided with slope surfaces (210) around them.

5. The solder preform according to claim 1, characterized in that: The thickness of the auxiliary welding piece (200) is less than or equal to the thickness of the edge strip enclosure (140), and the upper and lower surfaces of the auxiliary welding piece (200) are both planar structures.

6. The solder preform according to claim 1, characterized in that: The surfaces of the main welding sheet (100) and the auxiliary welding sheet (200) are both coated with soldering flux.

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