SMP connector mounting structure based on double-layer solder ring and welding method thereof

Abstract

The invention relates to the field of electronic installation processes, in particular to an SMP connector installation structure based on a double-layer solder ring and a welding method thereof.The installation structure comprises the steps that an installation hole is formed in a shell of an SMP connector to be installed, and the installation hole comprises a first through hole, a second through hole, a third through hole and a fourth through hole, wherein an annular platform formed at the joint of the first through hole and the second through hole is used for placing a first solder ring, an annular platform formed at the joint of the second through hole and the third through hole is used for placing a second solder ring, and an annular platform formed at the joint of the third through hole and the fourth through hole is used for clamping a second step of the SMP connector. When in use, the SMP connector and the preset solder ring are mounted in the mounting hole of the shell, and the high-temperature adhesive tape annular patch is used for plug limiting; the method has the characteristics of low cost, high product applicability, simplicity and convenience in operation and the like, is high in assembly yield and is suitable for batch production.

Description

Technical Field

[0001] The invention relates to the field of electronic assembly technology, and in particular to an SMP connector installation structure based on a double-layer solder ring and a welding method thereof. Background Art

[0002] SMP connectors connect or disconnect coaxial cables, microstrip circuits, and transmit signals in microwave circuits. They are important functional components for achieving electrical connections and signal transmission between modules, components, systems, and subsystems. They are widely used in many fields such as satellites, radars, and communications because of their small size, good broadband transmission characteristics, and convenient and reliable connection methods.

[0003] The SMP connector and the housing are usually assembled with a pre-set solder ring through a reflow process. Due to the assembly tolerances of the housing, SMP and solder ring, as well as the large differences in thermal expansion coefficients among the three, after the reflow process, the solder around the SMP connector becomes less and produces voids, making it difficult to achieve an airtight seal after a single assembly. It often requires a second repair to add solder to achieve a sealing effect. However, the gap between the housing and the SMP is small, which makes it difficult to add solder later.

[0004] At present, the main technical solution for fixing the SMP connector on a product or part is to put solder (such as a tin ring) into a mounting hole on the product or part for installing the SMP connector, then place the SMP connector in the mounting hole on the product or part, and then put the product or part into a reflow furnace for sintering, and finally fix the SMP connector in the mounting hole. However, due to errors in material size and human behavior, as well as the solder placed in the mounting hole being affected by gravity when it melts, the SMP connector may move out of place, resulting in poor quality of the final sintered product, which not only has poor appearance consistency, but also has a great impact on the electrical performance indicators of each channel. At present, most of the auxiliary devices that can be used to solve the above-mentioned displacement problem in the sintering process of the SMP connector are relatively complex and inconvenient to use. Summary of the invention

[0005] In view of the problems existing in the traditional method of using solder rings (spot-coated solder paste) and complex installation and positioning devices, the present invention proposes an SMP connector welding structure based on a double-layer solder ring, including: a mounting hole is opened on the shell of the SMP connector to be installed, the mounting hole includes a first through hole, a second through hole, a third through hole, a fourth through hole and a fifth through hole with multiple steps of diameters decreasing successively, wherein the circular platform formed at the connection between the first through hole and the second through hole is used to place the first solder ring, the circular platform formed at the connection between the second through hole and the third through hole is used to place the second solder ring, the circular platform formed at the connection between the third through hole and the fourth through hole is used to clamp the second step of the SMP connector, and the fourth through hole provides a through hole for the SMP connector lead to pass through.

[0006] Further, the sum of the depths of the first through hole, the second through hole and the third through hole is equal to the sum of the heights of the first step and the second step of the SMP connector.

[0007] Further, the depth of the second through hole is smaller than the height of the first step of the SMP connector.

[0008] Further, the sum of the depths of the first through hole and the second through hole is greater than the height of the first step of the SMP connector.

[0009] Furthermore, the height of the first solder ring is consistent with the height of the first through hole, the inner diameter of the first solder ring is equal to the diameter of the first step of the SMP connector, the outer diameter is equal to the diameter of the first through hole of the shell, and the sum of the volumes of the first solder ring, the second solder ring, and the first step and the second step of the SMP connector is equal to the sum of the volumes of the first through hole, the second through hole and the third through hole.

[0010] Further, a diameter of the third through hole matches a diameter of the second step of the SMP connector.

[0011] Furthermore, the diameter of the second through hole is slightly larger than the diameter of the first step of the SMP connector, and there is a gap between the two holes, which is only for the melted solder to flow.

[0012] The present invention also provides a method for using an SMP connector welding structure based on a double-layer solder ring, and reflow soldering is performed on an SMP connector using an SMP connector mounting structure based on a double-layer solder ring, specifically comprising the following steps:

[0013] Using a writing brush, evenly apply liquid flux to the surface of the SMP outer conductor and the mounting hole, place the first solder ring and the second solder ring at corresponding positions in the mounting structure, and install the SMP connector into the mounting hole;

[0014] Use tweezers to stick the high-temperature tape sticker on the housing and the SMP connector mounting end surface. The high-temperature tape sticker covers the gap between the mounting structure and the SMP connector to limit the SMP connector.

[0015] Put the assembled SMP connector together with the shell into a reflow oven at a suitable temperature for soldering. After the solder ring melts, take it out and cool it to complete the assembly. At this time, under the pressure of the tape and the flow of the solder, the excess solder of the second solder ring will automatically flow to fill the gap between the SMP connector and the mounting hole of the shell.

[0016] Furthermore, the high temperature tape sticker is a ring structure, the outer diameter of the ring should be larger than the diameter of the housing mounting hole, and the inner diameter of the ring is smaller than the diameter of the first step of the SMP connector.

[0017] Furthermore, before welding, ultrasonic cleaning is performed using a mixed solution of anhydrous ethanol and acetone to remove surface contaminants. Compared with the traditional SMP connector welding structure, the present invention has the following significant advantages: through the design of a double-layer solder ring mounting shell structure, the installation and positioning are performed using a high-temperature adhesive tape sticker, so as to achieve high-precision and airtight welding requirements between the SMP connector and the shell. The present invention has the characteristics of low cost, strong product applicability, simple operation, high assembly yield, and is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of a general SMP connector in the prior art;

[0019] Figure 2 It is a cross-sectional schematic diagram of a SMP connector welding structure based on a double-layer solder ring of the present invention;

[0020] Figure 3 It is a schematic diagram of assembling an SMP connector welding structure based on a double-layer solder ring in a welding structure according to the present invention;

[0021] Among them, 1, the first through hole; 2, the second through hole; 3, the third through hole; 4, the fourth through hole. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The present invention proposes an SMP connector welding structure based on a double-layer solder ring, comprising: a mounting hole is opened on a shell body to be installed with an SMP connector, the mounting hole comprises a first through hole, a second through hole, a third through hole and a fourth through hole with diameters decreasing in sequence in multiple steps, wherein a circular platform formed at the connection between the first through hole and the second through hole is used to place the first solder ring, a circular platform formed at the connection between the second through hole and the third through hole is used to place the second solder ring, a circular platform formed at the connection between the third through hole and the fourth through hole is used to clamp the second step of the SMP connector, and the fifth through hole is a through hole only for the SMP connector lead to pass through.

[0024] For the sake of Figure 1 The SMP connector shown in the figure is welded, and the present invention proposes a welding structure suitable for the structure. The SMP connector includes a first step and a second step, and a lead is led out from the axis of the second step. The height of the first step of the SMP is A, and the cross-sectional diameter of the first step is The height of the second step of SMP is CA, and the cross-sectional diameter of the first step is

[0025] The present invention proposes a SMP connector welding structure based on a double-layer solder ring. Figure 2 As shown, the housing can be customized as needed. The present invention mainly defines the portion of the housing where the SMP connector is installed, such as Figure 2 A mounting hole structure is provided on the shell, and the mounting hole is a through-hole structure as a whole, which is composed of a plurality of through-holes of different diameters connected, that is, the mounting hole includes a first through-hole, a second through-hole, a third through-hole and a fourth through-hole with diameters decreasing in sequence. The circular platform formed at the connection between the first through-hole and the second through-hole is used to place the first solder ring, the circular platform formed at the connection between the second through-hole and the third through-hole is used to place the second solder ring, and the circular platform formed at the connection between the third through-hole and the fourth through-hole is used to clamp the second step of the SMP connector, that is, the SMP connector will not fall, and the SMP connector is clamped as a whole, so that the diameter of the fourth through-hole is smaller than the diameter of the second step of the SMP connector and the lead of the SMP connector can pass through the fourth through-hole. During welding, after the SMP connector and the pre-set solder ring are installed into the mounting hole of the shell, a high-temperature tape annular patch is used to block and limit the position of the end face of the first through-hole, and the high-temperature tape annular patch seals the gap between the SMP connector and the first through-hole, thereby ensuring the position accuracy of the SMP connector during the reflow soldering process.

[0026] In the process of implementing the present invention, Figure 3 , the diameter of the second through hole of the housing is equal to the diameter of the first step of the SMP connector + the width of the solder ring 1, and the depth of the first through hole is the thickness of the solder ring 1;

[0027] The diameter of the second through hole of the housing is slightly larger than the diameter of the first step of the SMP connector, leaving a gap for the solder to flow downward under gravity after melting. Those skilled in the art can set it according to actual conditions. The depth of the first through hole and the second through hole is equal to the height A of the first step of the SMP connector + the thickness of the solder ring 2;

[0028] The diameter of the third through hole is equal to the diameter of the second step of the SMP connector, and the depth of the third through hole is equal to the height of the second step of the SMP connector minus the thickness of the solder ring 2;

[0029] The diameter of the fourth through hole is smaller than the diameter of the second step of the SMP connector, and other dimensions can be set according to actual conditions;

[0030] The fifth through hole is only for the lead wire of the SMP connector to pass through, and is used to limit the position of the SMP connector during the welding process.

[0031] In the specific implementation process, solder ring 1 and solder ring 2 can be in the form of customized solder rings, or they can be pre-filled with equal volumes of solder paste. In one embodiment, it is achieved by customizing the solder ring, and the height of the customized solder ring 1 is the same as the height of the first through hole; the inner diameter is equal to the diameter of the first step of the SMP connector, and the outer diameter is equal to the diameter of the first through hole of the shell. In this embodiment, it is necessary to ensure that the solder ring 1 can be loaded into the welding structure, so a negative tolerance is selected when preparing the solder ring to ensure that the solder ring 1 can be smoothly loaded into the welding structure; when customizing the solder ring 2, it is ensured that the total volume of the first step and the second step of the SMP connector + the volume of the solder ring 1 + the volume of the solder ring 2 = the volume of the first, second, and third through holes of the shell mounting hole, thereby determining the solder ring pre-set volume. The amount of solder ring 2 should be measured in advance to reduce the welding voids of the SMP connector; when designing the solder ring 2, the actual processing size of the shell mounting hole should be measured in advance, and the thickness of the solder ring 2 should be adjusted and designed according to the processing conditions of the shell mounting hole. While ensuring the welding quality, it reduces the dependence on the shell processing accuracy. Due to the existence of processing tolerances, after the SMP connector is installed in the welding structure, a part of the tail of the SMP connector will emerge, that is, the first through hole and the first step end face of the SMP connector are not flush. This error is allowed in actual operation. After actual operation, it is shown that the effect of this error on welding can be ignored. In another embodiment, the solder paste with a fixed amount of solder paste is calculated according to the proportion of solid metal content to replace the customized solder ring. The sum of the volume of the solder paste used and the volume of the first step and the second step of the SMP connector is equal to the sum of the volumes of the first through hole, the second through hole and the third through hole. Part of the solder paste is applied to the circular platform formed at the connection between the first through hole and the second through hole of the solder to form the first solder ring, and the remaining solder paste is applied to the circular platform formed at the connection between the second through hole and the third through hole to form the second solder ring.

[0032] As an optional embodiment, the present invention also provides a method for using an SMP connector welding structure based on a double-layer solder ring, and welding SMP using the aforementioned SMP connector welding structure based on a double-layer solder ring, specifically comprising the following steps:

[0033] First, check whether there are burrs or other redundant objects on the SMP mounting holes of the shell after nickel-gold electroplating, and then use an ethanol and acetone mixed solution for ultrasonic cleaning to remove surface oil stains, salt and other pollutants. As an optional implementation, the volume ratio of ethanol and acetone solution is 2:1;

[0034] Next, a thin layer of liquid solder flux is evenly applied on the surface of the outer conductor of the SMP connector using a brush, and a solder ring 2 is installed on the surface of the first step and the second step of the SMP outer shell. As an option, a thin layer of solder flux can be pre-placed outside the solder ring;

[0035] After the SMP connector is pushed into the mounting hole, the solder ring 1 is placed. In addition, the solder ring 1 and the solder ring 2 used in the present invention do not need to be customized, and the same volume of solder paste is directly applied to the positions of the solder ring 1 and the solder ring 2, which further saves costs. In addition, the solder paste contains flux to ensure wetting;

[0036] Then, use tweezers to stick the special high-temperature tape sticker on the housing and the SMP connector installation end face, and limit the tail end to prevent the solder from flowing after melting and causing the SMP connector to deflect and misalign. The high-temperature tape can be prepared by laser engraving or mold stamping. The high-temperature tape has a low cost and can effectively save costs in the welding process.

[0037] Place the installed products in a reflow oven with a suitable temperature curve for reflow, and soldering can be achieved when the solder melts;

[0038] Put the product into the cleaning agent to scrub away the flux residue and bake it in a 100℃ oven for 20 minutes to dry it, and then complete the assembly;

[0039] If there is poor welding, the first solder ring can be repaired by filling with tin using a heating table or hot air blower.

[0040] In this embodiment, the high-temperature tape sticker is a ring structure, the outer diameter of the ring should be larger than the diameter of the shell mounting hole, and the inner diameter of the ring should be smaller than the diameter of the first step of the SMP connector; in addition, the selected high-temperature tape paper should be able to withstand the reflow soldering temperature of 260°C and maintain viscosity during the reflow soldering process.

[0041] In the description of the present invention, it is necessary to understand that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "outside", "front", "center", "both ends" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0042] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "rotation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0043] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A SMP connector mounting structure based on a double-layer solder ring, characterized in that: A mounting hole is opened on the shell on which the SMP connector is to be installed, and the mounting hole includes a first through hole, a second through hole, a third through hole, a fourth through hole and a fifth through hole with diameters decreasing in sequence in multiple steps, wherein the circular platform formed at the connection between the first through hole and the second through hole is used to place the first solder ring, the circular platform formed at the connection between the second through hole and the third through hole is used to place the second solder ring, the circular platform formed at the connection between the third through hole and the fourth through hole is used to clamp the second step of the SMP connector, and the fourth through hole provides a through hole for the lead of the SMP connector to pass through.

2. The SMP connector welding structure based on a double-layer solder ring according to claim 1, characterized in that: The sum of the depths of the first through hole, the second through hole, and the third through hole is equal to the sum of the heights of the first step and the second step of the SMP connector.

3. The SMP connector welding structure based on a double-layer solder ring according to claim 2, characterized in that: The depth of the second through hole is less than the height of the first step of the SMP connector.

4. The SMP connector welding structure based on a double-layer solder ring according to claim 2, characterized in that: The sum of the depths of the first through hole and the second through hole is greater than the height of the first step of the SMP connector.

5. The SMP connector welding structure based on a double-layer solder ring according to claim 1, characterized in that: The height of the first solder ring is consistent with the height of the first through hole, the inner diameter of the first solder ring is equal to the diameter of the first step of the SMP connector, the outer diameter is equal to the diameter of the first through hole of the shell, and the sum of the volumes of the first solder ring, the second solder ring, and the first step and the second step of the SMP connector is equal to the sum of the volumes of the first through hole, the second through hole and the third through hole.

6. The SMP connector welding structure based on a double-layer solder ring according to claim 1, characterized in that: The diameter of the third through hole matches the diameter of the second step of the SMP connector.

7. The SMP connector welding structure based on a double-layer solder ring according to claim 1, characterized in that: The diameter of the second through hole is slightly larger than the diameter of the first step of the SMP connector, and there is a gap between the two holes that is only enough for the melted solder to flow.

8. A method for using a SMP connector welding structure based on a double-layer solder ring, characterized in that: Reflow soldering of an SMP connector using the SMP connector mounting structure based on a double-layer solder ring as described in claim 1 specifically comprises the following steps: Using a writing brush, evenly apply liquid flux to the surface of the SMP outer conductor and the mounting hole, place the first solder ring and the second solder ring at corresponding positions in the mounting structure, and install the SMP connector into the mounting hole; Use tweezers to stick the high-temperature tape sticker on the housing and the SMP connector mounting end surface. The high-temperature tape sticker covers the gap between the mounting structure and the SMP connector to limit the SMP connector. Put the assembled SMP connector together with the shell into a reflow oven at a suitable temperature for soldering. After the solder ring melts, take it out and cool it to complete the assembly. At this time, under the pressure of the tape and the flow of the solder, the excess solder of the second solder ring will automatically flow to fill the gap between the SMP connector and the mounting hole of the shell.

9. The method for using the SMP connector welding structure based on a double-layer solder ring according to claim 8, characterized in that: The high temperature tape sticker has a ring structure. The outer diameter of the ring should be larger than the diameter of the housing mounting hole, and the inner diameter of the ring should be smaller than the diameter of the first step of the SMP connector.

10. The method for using the SMP connector welding structure based on a double-layer solder ring according to claim 8, characterized in that: Before welding, ultrasonic cleaning is performed using a mixed solution of anhydrous ethanol and acetone to remove surface contaminants.

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