A method of wave soldering terminals of a connector

Abstract

The application relates to a method for tin plating on through holes of a connector, comprising the following steps: installing a tin plating mold into a tin plating carrier plate, installing a steel net above the tin plating mold, filling tin paste into a tin storage groove of the tin plating mold, removing the steel net, picking up the tin plating mold, installing the connector on a printed board, installing the tin plating mold at a welding through hole position of the connector, assembling a product to be welded, feeding the product to be welded, which is assembled with the tin plating mold, the printed board and the connector, into a reflow furnace, melting the solder in the tin plating mold by heat, and flowing the melted solder into the through hole under the action of capillary and gravity, so as to realize tin plating on the through hole part, removing the tin plating mold after the product to be welded is taken out of the reflow furnace, and completing the reflow soldering. In a word, the application has the advantages of low processing cost, short processing period, high tin plating efficiency, wide application range and high welding qualification rate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic product assembly and processing, and particularly relates to a through-hole reflow soldering and tinning method for connectors. BACKGROUND

[0002] Many electronic products in the aviation field use plug-in devices, such as connectors. When hundreds of connectors with thousands of pins need to be welded, the traditional selective wave soldering method has low welding efficiency, insufficient tinning filling rate and is prone to welding defects such as bridging, which cannot meet the requirements. At present, the through-hole reflow soldering technology is more commonly used. The through-hole reflow soldering technology can greatly improve the assembly efficiency and tinning qualification rate. The through-hole reflow soldering technology refers to a method of filling tin paste into holes, laying tin paste on the hole edge or sleeving a prefabricated solder ring on the pin. The solder is laid in the pin hole, on the hole edge or above the hole. The solder is melted by the reflow furnace, and the molten solder fills / flows into the hole, thereby realizing welding. However, the existing through-hole reflow soldering tinning method has problems of high tinning cost, difficult tin paste quantity control and poor adaptability to high-density printed boards.

[0003] The existing through-hole reflow soldering tinning method has the following problems in use: the tin paste is injected into the hole in the form of injection, the tinning efficiency is low, and the tin paste quantity is difficult to control; the tin paste is printed into the hole in the form of steel mesh printing, each new printed board needs to develop a new steel mesh and new test printing parameters, which increases the cost and affects the efficiency; during the process of the plug-in device after the tin paste is injected into the hole, the pin is easy to push out the tin paste, resulting in insufficient soldering; the tin paste is printed on the hole edge in the form of steel mesh printing, each new printed board needs to develop a new steel mesh and new test printing parameters, which increases the cost and affects the efficiency, and the tin paste is printed on the hole edge, which needs to occupy the area on both sides of the through hole of the printed board, which is not suitable for high-density printed boards; when the distance between the through holes is small, the tin paste is printed on the hole edge, and during the welding process, the solder between the adjacent pin holes is easy to melt together under the disturbance of hot air and machine vibration, causing short circuit or insufficient soldering on part of the pin; for some printed boards with thick thickness and high device layout density, it is often necessary to use stepped steel mesh or steel mesh with overlay printing, which causes high processing cost, and the use of steel mesh for tinning of high-density printed board assembly requires excessive amount of tin paste, the steel mesh is thick and difficult to demold, and some tinning processes using prefabricated solder rings not only have the problem of easy short circuit when the solder ring melts, but also have the problems of high customizing cost of prefabricated solder rings and long installation time, which causes cost increase and efficiency reduction.

[0004] Therefore, there is an urgent need for a through-hole reflow soldering tinning method for connectors to solve the above problems. SUMMARY

[0005] In view of the above, the present application provides a method for tin plating through-hole reflow soldering of a connector, which is applied to the technical field of electronic product assembly and can solve the technical problems of high processing cost, long processing cycle and low product success rate.

[0006] In order to achieve the above technical purpose, the specific technical scheme adopted by the present application is as follows:

[0007] A method for tin plating through-hole reflow soldering of a connector, comprising the following steps:

[0008] S1, install the tin plating mold into the tin plating carrier plate, install the steel mesh above the tin plating mold, fill the solder paste into the solder storage groove of the tin plating mold, remove the steel mesh, and pick up the tin plating mold;

[0009] S2, install the connector on the printed board, install the tin plating mold at the position of the soldering through hole of the connector, and assemble to form a product to be soldered;

[0010] S3, send the product to be soldered assembled with the tin plating mold, the printed board and the connector into the reflow furnace, use heat to melt the solder in the tin plating mold, and the melted solder flows into the through hole due to capillary action and gravity, thereby realizing tin plating of the through hole part;

[0011] S4, after the product to be soldered comes out of the reflow furnace, remove the tin plating mold, and complete the through-hole reflow soldering;

[0012] The tin plating mold in step S1 comprises a mold bottom plate and a plurality of solder storage grooves arranged on the mold bottom plate, the plurality of solder storage grooves are upwardly open, and are uniformly distributed on the top of the mold bottom plate;

[0013] The steel mesh in step S1 is provided with a plurality of tin plating through holes matched with the shape of the tin plating mold, and the plurality of tin plating through holes are uniformly distributed on the surface of the steel mesh;

[0014] The tin plating carrier plate in step S1 comprises a plurality of mold installation grooves matched with the shape of the tin plating mold, the position of each mold installation groove corresponds to the position of the corresponding tin plating through hole in the horizontal direction in the process of filling the solder paste, and each mold installation groove is located below the corresponding tin plating through hole.

[0015] Further, in step S2, the connector is provided with a plurality of connector pins extending upward, the plurality of connector pins vertically extend upward and deeply into the printed board, and the plurality of solder storage grooves on the tin plating mold are correspondingly arranged in the horizontal direction with the plurality of connector pins.

[0016] Further, in step S2, the connector is further provided with two connector mounting holes with upward openings, and the two connector mounting holes are respectively located on the horizontal outer side of the plurality of connector pins.

[0017] Further, in step S3, the solder paste is filled into the tin storage groove of the upper tin mold by using a silk screen method, and the filling of the solder paste is operated by a doctor blade.

[0018] Further, in step S1, the horizontal two ends of the mold bottom plate are provided with fixed through holes opening upward, and the two fixed through holes are located outside the plurality of tin storage grooves.

[0019] Further, in step S1, the shape of the tin storage groove is a rectangular groove, and the plurality of tin storage grooves are distributed in two rows, and the tin storage grooves in each row are uniformly distributed in the transverse direction.

[0020] Further, in step S1, the opening area and the thickness of the tin storage groove inside the upper tin mold satisfy the following requirements:

[0021]

[0022] S is the opening area of the tin storage groove of the upper tin mold, t1 is the thickness of the upper tin mold, r1 is the radius of the plug-in pin at the to-be-welded position, r2 is the radius of the welding through hole, r3 is the radius of the through hole surface pad, t2 is the thickness of the printed board, k is the volume ratio of the solder alloy, and μ is an empirical coefficient.

[0023] By adopting the above technical scheme, the present application can also bring the following beneficial effects:

[0024] 1. The present application provides a method for reflow soldering of a plug-in connector, which can meet the requirements of reflow soldering of a plug-in connector, solve the problem of no space for soldering of a high-density printed board assembly, and the problem of short circuit and poor soldering of a fine-pitch through-hole device, has the advantages of low cost, less preparation, batch processing, high soldering efficiency, and the developed soldering mold can be applied to different layouts of printed board assemblies under the condition that the thickness of the printed board is similar, the pitch of the plug-in pin is similar, and the size of the plug-in pin is similar, has strong universality, and is very suitable for popularization.

[0025] 2. The present application provides a method for reflow soldering of a plug-in connector, which can meet the requirements of reflow soldering of a plug-in connector, solve the problem of no space for soldering of a high-density printed board assembly, and the problem of short circuit and poor soldering of a fine-pitch through-hole device, has the advantages of low cost, less preparation, batch processing, high soldering efficiency, and the developed soldering mold can be applied to different layouts of printed board assemblies under the condition that the thickness of the printed board is similar, the pitch of the plug-in pin is similar, and the size of the plug-in pin is similar, has strong universality, and is very suitable for popularization.

[0026] 3、The application discloses a through-hole reflow soldering tin method for connectors, which can solve the problems of demolding difficulty, short circuit after soldering and partial pin empty welding caused by the steel mesh demolding method during the through-hole reflow soldering tin process, realizes one-time successful assembly of more than 99%, avoids multiple steel mesh manufacturing during the introduction of new products, reduces the repair rate, reduces the human, material and time loss caused by repair, saves the economic cost, and is simple in structure, easy to produce, process and assemble, and can be used in the through-hole reflow soldering technology in various special scenes. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0028] Figure 1 The application discloses a through-hole reflow soldering tin method for connectors, which can solve the problems of demolding difficulty, short circuit after soldering and partial pin empty welding caused by the steel mesh demolding method during the through-hole reflow soldering tin process, realizes one-time successful assembly of more than 99%, avoids multiple steel mesh manufacturing during the introduction of new products, reduces the repair rate, reduces the human, material and time loss caused by repair, saves the economic cost, and is simple in structure, easy to produce, process and assemble, and can be used in the through-hole reflow soldering technology in various special scenes.

[0029] Figure 2 The application discloses a through-hole reflow soldering tin method for connectors, which can solve the problems of demolding difficulty, short circuit after soldering and partial pin empty welding caused by the steel mesh demolding method during the through-hole reflow soldering tin process, realizes one-time successful assembly of more than 99%, avoids multiple steel mesh manufacturing during the introduction of new products, reduces the repair rate, reduces the human, material and time loss caused by repair, saves the economic cost, and is simple in structure, easy to produce, process and assemble, and can be used in the through-hole reflow soldering technology in various special scenes.

[0030] Figure 3 The application discloses a through-hole reflow soldering tin method for connectors, which can solve the problems of demolding difficulty, short circuit after soldering and partial pin empty welding caused by the steel mesh demolding method during the through-hole reflow soldering tin process, realizes one-time successful assembly of more than 99%, avoids multiple steel mesh manufacturing during the introduction of new products, reduces the repair rate, reduces the human, material and time loss caused by repair, saves the economic cost, and is simple in structure, easy to produce, process and assemble, and can be used in the through-hole reflow soldering technology in various special scenes.

[0031] Figure 4 The application discloses a through-hole reflow soldering tin method for connectors, which can solve the problems of demolding difficulty, short circuit after soldering and partial pin empty welding caused by the steel mesh demolding method during the through-hole reflow soldering tin process, realizes one-time successful assembly of more than 99%, avoids multiple steel mesh manufacturing during the introduction of new products, reduces the repair rate, reduces the human, material and time loss caused by repair, saves the economic cost, and is simple in structure, easy to produce, process and assemble, and can be used in the through-hole reflow soldering technology in various special scenes.

[0032] Figure 5 The application discloses a through-hole reflow soldering tin method for connectors, which can solve the problems of demolding difficulty, short circuit after soldering and partial pin empty welding caused by the steel mesh demolding method during the through-hole reflow soldering tin process, realizes one-time successful assembly of more than 99%, avoids multiple steel mesh manufacturing during the introduction of new products, reduces the repair rate, reduces the human, material and time loss caused by repair, saves the economic cost, and is simple in structure, easy to produce, process and assemble, and can be used in the through-hole reflow soldering technology in various special scenes.

[0033] Figure 6 The application discloses a through-hole reflow soldering tin method for connectors, which can solve the problems of demolding difficulty, short circuit after soldering and partial pin empty welding caused by the steel mesh demolding method during the through-hole reflow soldering tin process, realizes one-time successful assembly of more than 99%, avoids multiple steel mesh manufacturing during the introduction of new products, reduces the repair rate, reduces the human, material and time loss caused by repair, saves the economic cost, and is simple in structure, easy to produce, process and assemble, and can be used in the through-hole reflow soldering technology in various special scenes.

[0034] Figure 7 The application discloses a through-hole reflow soldering tin method for connectors, which can solve the problems of demolding difficulty, short circuit after soldering and partial pin empty welding caused by the steel mesh demolding method during the through-hole reflow soldering tin process, realizes one-time successful assembly of more than 99%, avoids multiple steel mesh manufacturing during the introduction of new products, reduces the repair rate, reduces the human, material and time loss caused by repair, saves the economic cost, and is simple in structure, easy to produce, process and assemble, and can be used in the through-hole reflow soldering technology in various special scenes.

[0035] Figure 8 The application discloses a through-hole reflow soldering tin method for connectors, which can solve the problems of demolding difficulty, short circuit after soldering and partial pin empty welding caused by the steel mesh demolding method during the through-hole reflow soldering tin process, realizes one-time successful assembly of more than 99%, avoids multiple steel mesh manufacturing during the introduction of new products, reduces the repair rate, reduces the human, material and time loss caused by repair, saves the economic cost, and is simple in structure, easy to produce, process and assemble, and can be used in the through-hole reflow soldering technology in various special scenes.

[0036] Among them: 1. Steel mesh; 2. Tinning mold; 3. Tinning carrier board; 4. Printed circuit board; 5. Connector; 6. Mold base plate; 7. Tin storage tank; 8. Fixing through hole; 9. Mold mounting slot; 10. Connector mounting hole; 11. Connector pin; 12. Tinning through hole; 13. Screw mounting hole; 14. Soldering through hole; 15. Through hole surface pad; 16. Mold clamping slot. DETAILED DESCRIPTION

[0037] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0038] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present invention, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0040] It should also be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. The illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0041] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples. However, one skilled in the art will appreciate that the aspects described can be practiced without these specific details.

[0042] In one embodiment of the present application, as shown in Figures 1 to 8 The present application refers to a method for soldering through-hole of connector 5, comprising the following steps:

[0043] Step S1, install the soldering mold 2 into the soldering carrier plate 3, install the steel mesh 1 above the soldering mold 2, fill the solder paste into the opening of the soldering mold 2 by the doctor blade, remove the steel mesh 1, pick up the soldering mold 2;

[0044] Step S2, install the connector 5 to the designated position of the printed board 4, install the soldering mold 2 to the position of the welding through-hole 14 of the connector 5, form the product to be welded;

[0045] Step S3, send the product to be welded assembled with the soldering mold 2, the printed board 4 and the connector 5 into the general equipment reflow furnace, melt the solder in the soldering mold by heat, and the melted solder flows into the welding through-hole 14 due to capillary and gravity, realizing the soldering of the connector 5;

[0046] Step S4, after the product to be welded comes out of the reflow furnace, remove the soldering mold 2, and finally complete the through-hole reflow soldering.

[0047] In this example, all tolerances of the soldering mold 2 are controlled within ±0.05mm; the soldering mold 2 comprises a mold bottom plate 6 and a plurality of solder storage grooves 7 arranged on the mold bottom plate 6, the plurality of solder storage grooves 7 are upwardly open and uniformly distributed on the top of the mold bottom plate 6; the steel mesh 1 is provided with a plurality of soldering through-holes 12 matched with the shape of the soldering mold 2, and the plurality of soldering through-holes 12 are uniformly distributed on the surface of the steel mesh 1; the soldering carrier plate 3 comprises a plurality of mold installation grooves 9 matched with the shape of the soldering mold 2, the position of each mold installation groove 9 corresponds to the position of the corresponding soldering through-hole 12 in the horizontal direction during the process of filling the solder paste, and each mold installation groove 9 is located below the corresponding soldering through-hole 12.

[0048] In this example, the pin radius r1 of the connector 5 is 0.25mm, the welding through-hole radius r2 is 0.35mm, the through-hole surface pad 15 radius r3 is 0.5mm, the through-hole surface pad 15 is arranged on the top of the welding through-hole 14, the thickness t2 of the printed board 4 is 3.5mm, the solder alloy volume ratio k is 0.5, and the opening area and thickness of the soldering mold 2 are calculated according to the following formula:

[0049]

[0050] S. The opening area of the tin storage groove 7 of the upper tin mold 2; t1, the thickness of the upper tin mold 2; r1, the radius of the connector pin 11 at the welding position; r2, the radius of the welding through hole 14; r3, the radius of the through hole surface pad 15; t2, the thickness of the printed board 4; k, the volume ratio of the tin paste alloy; μ, the empirical coefficient, the opening area and the thickness of the upper tin mold 2 obtained according to the empirical coefficient:

[0051]

[0052] According to the distribution of the device on the printed board 4 and the distribution of the connector pin 11 on the connector 5, the tin storage groove 7 is determined to be a rectangle with a length L=2.2mm and a width W=0.9mm, and the area of the tin storage groove 7 is calculated:

[0053] S=L*W=1.98mm 2

[0054] The upper tin mold 2 and the upper tin carrier plate 3 are made of 6061 aluminum alloy, and the surface is not plated, so the empirical coefficient μ is 0.9, and the thickness of the upper tin mold 2 is calculated

[0055]

[0056] If the material or surface plating of the upper tin mold 2 and the upper tin carrier plate 3 is changed, after determining the opening area, a test piece is made, and a new μ is developed by picking up the solder volume remaining in the mold mounting groove 9 of the upper tin mold 2 during the process; in order to facilitate processing, t1 is taken as 0.9mm, and the size of the tin storage groove 7 is L*W*t1=2.2mm*0.9mm*0.9mm.

[0057] The distribution direction of the welding through hole 14, the size and distribution direction of the screw mounting hole 13, and the distribution design of the device on the printed board 4 are designed, the screw mounting hole 13 and the welding through hole 14 are arranged on the upper surface of the printed board 4, the shape of the tin storage groove 7 is a rectangular groove, a plurality of tin storage grooves 7 are arranged in two rows, the tin storage grooves 7 in each row are uniformly distributed in the horizontal direction, the horizontal two ends of the mold bottom plate 6 are provided with fixed through holes 8 opening upward, and the two fixed through holes 8 are located on the outer side of the plurality of tin storage grooves 7, and the size and position are consistent with the screw mounting hole 13.

[0058] According to the size of the tin-plating mold 2 and the number of connectors 5 to be welded on the printed board 4, the tin-plating carrier 3 is designed. In this example, ten connectors 5 are used on the printed board 4. In order to easily remove the tin-plating mold 2 from the mold mounting groove later, the size of the mold mounting groove 9 is slightly larger than the size of the tin-plating mold 2. The length and width of the mold mounting groove 9 are 0.1 mm larger than the length and width of the tin-plating mold 2 respectively. In order to make the surface of the steel mesh 1 flush with the surface of the tin-plating mold 2 after the steel mesh 1 is installed later, the depth of the mold mounting groove 9 is 0.1 mm less than the thickness of the tin-plating mold 2, which is designed to be 0.8 mm. In order to facilitate the clamping of the tin-plating mold 2 after the tin-plating is completed, a mold clamping groove 16 is provided in the middle of the mold mounting groove 9. The mold mounting groove 9 and the mold clamping groove 16 are located on the upper surface of the tin-plating carrier 3. The size of the mold clamping groove 16 is 10 mm*3.0 mm.

[0059] According to the size of the tin-plating mold 2 and the orientation of the mold mounting groove 9, the thickness of the steel mesh 1 is set to 0.1 mm. The size of the tin-plating through hole 12 is slightly larger than the size of the tin-plating mold 2. The length and width of the tin-plating through hole 12 are 0.05 mm larger than the length and width of the tin-plating mold 2 respectively.

[0060] In this example, the connector 5 is provided with a plurality of upwardly extending connector pins 11. The plurality of connector pins 11 vertically extend upwardly into the printed board 4. The plurality of tin storage grooves 7 on the tin-plating mold 2 are correspondingly arranged in the horizontal direction with the connector pins 11. The connector 5 is also provided with two connector mounting holes 10 that are open upwardly. The two connector mounting holes 10 are respectively located on the horizontal outer side of the plurality of connector pins 11.

[0061] In summary, the present application has the advantages of low processing cost, short processing cycle, high tin-plating efficiency, wide application range and high welding qualification rate.

[0062] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical range disclosed by the present application can be easily thought of by those skilled in the art, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of wave soldering terminals of a connector, characterized by, The method comprises the following steps: S1, install the upper tin mold (2) into the upper tin carrier board (3), install the steel mesh (1) above the upper tin mold (2), fill the tin paste into the tin storage groove (7) of the upper tin mold (2), remove the steel mesh (1), pick up the upper tin mold (2); S2, install the connector (5) on the printed board (4), install the upper tin mold (2) to the position of the welding through hole (14) of the connector (5), and assemble to form a product to be welded; The connector (5) is provided with a plurality of upward extending connector pins (11), and the plurality of connector pins (11) vertically and upwardly penetrate into the printed board (4), and a plurality of tin storage grooves (7) on the upper tin mold (2) are correspondingly arranged in the horizontal direction with the connector pins (11). S3, send the assembled product to be welded of the upper tin mold (2), the printed board (4) and the connector (5) into the reflow oven, melt the solder tin in the upper tin mold (2) by using heat, and the melted solder tin flows into the welding through hole (14) due to capillary and gravity, so as to realize the upper tin of the connector (5); S4, after the product to be welded comes out of the reflow oven, remove the upper tin mold (2), and complete the through-hole reflow soldering; The upper tin mold (2) in the step S1 comprises a mold bottom plate (6) and a plurality of tin storage grooves (7) arranged on the mold bottom plate (6), the plurality of tin storage grooves (7) are upwardly opened, and are uniformly distributed on the top of the mold bottom plate (6); The steel mesh (1) in the step S1 is provided with a plurality of upper tin through holes (12) matched with the shape of the upper tin mold (2), and the plurality of upper tin through holes (12) are uniformly distributed on the surface of the steel mesh (1); The upper tin carrier board (3) in the step S1 comprises a plurality of mold installation grooves (9) matched with the shape of the upper tin mold (2), and the position of each mold installation groove (9) corresponds to the position of the corresponding upper tin through hole (12) in the horizontal direction in the process of filling the tin paste, and each mold installation groove (9) is located below the corresponding upper tin through hole (12).

2. A method of wave soldering terminals to a connector according to claim 1, wherein: In the step S2, the connector (5) is further provided with two connector mounting holes (10) which are upwardly opened, and the two connector mounting holes (10) are respectively located on the horizontal outer side of the plurality of connector pins (11).

3. A method of wave soldering terminals to a connector according to claim 2, wherein: In the step S3, the tin paste is filled into the tin storage groove (7) of the upper tin mold (2) by using the silk screen method, and the filling of the tin paste is operated by a doctor blade.

4. A method of wave soldering terminals to a connector according to claim 3, wherein: In the step S1, the horizontal two ends of the mold bottom plate (6) are provided with fixed through holes (8) which are upwardly opened, and the two fixed through holes (8) are respectively located on the outer side of the plurality of tin storage grooves (7).

5. A method of wave soldering terminals to a connector according to claim 4, wherein: In the step S1, the shape of the tin storage groove (7) is a rectangular groove, and the plurality of tin storage grooves (7) are distributed in two rows, and the tin storage grooves (7) in each row are uniformly distributed in the transverse direction.

6. A method of wave soldering terminals to a connector according to claim 5, wherein: In the step S1, the opening area and the thickness of the internal tin storage groove (7) of the upper tin mold (2) meet the following requirements: S is the opening area of the tin storage groove (7) of the upper tin mold (2), t1 is the thickness of the upper tin mold (2), r1 is the radius of the plug-in pin (11) at the welding position, r2 is the radius of the welding through hole (14), r3 is the radius of the through hole surface pad (15), t2 is the thickness of the printed board (4), k is the volume ratio of the tin paste alloy, and μ is an empirical coefficient.

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