Structure and method capable of preparing outgoing line high-voltage welding spots in batches

Abstract

The invention discloses a structure and method capable of preparing outgoing line high-voltage welding spots in batches, and relates to the field of electronic assembly. Grooves are formed in the surfaces of the upper die and the lower die, and the groove sides of the upper die and the lower die are opposite to form a welding spot welding area. Pre-fixing to-be-welded parts of the lead outgoing line and the component pin to obtain to-be-welded parts; first clamping grooves and second clamping grooves are formed in the edges of the opposite sides of the upper mold and the lower mold, lead outgoing lines are clamped into the opposite first clamping grooves, component pins are clamped into the opposite second clamping grooves, so that the to-be-welded parts are located in the welding spot welding area, and the other ends of the lead outgoing lines and the other ends of the component pins are located outside the welding spot tool mold; a welding flux inflow hole is formed in the surface of one side of the upper die and communicates with the welding spot welding area, and molten welding flux flows into the welding spot welding area through the welding flux inflow hole to be cooled to form welding spots. The problems that a one-time heat transfer mode of traditional manual welding or laser welding is narrow in area and low in welding efficiency are solved.

Description

Technical Field

[0001] The invention belongs to the field of electronic assembly, and relates to a method for preparing high-voltage solder joints, in particular to a method for batch preparing high-voltage solder joints of lead wires. Background Art

[0002] A large number of high-voltage components are required in aerospace high-voltage products, such as transformers, power tubes, and relays. During the product development process, wires are needed as lead wires to achieve electrical connections between various high-voltage components. In order to improve the electrical insulation safety of high-voltage aerospace products, the solder joints between the lead wires and the pins of the high-voltage components need to be welded into high-voltage solder joints, that is, after welding, the surface is smooth and round, without sharp points or burrs, and is hemispherical, spherical, or date-shaped, so as to control the distribution of electric field strength in the product, avoid local field strength concentration caused by sharp points and sharp angles, and reduce electrical insulation reliability. At present. There are three commonly used high-voltage solder joint welding methods in the industry:

[0003] The first one is the manual secondary soldering method using an electric soldering iron mentioned in patent document CN 105252094B. The main object is the discrete components on the printed circuit board. By controlling the lead length before assembly, combining secondary tinning and secondary soldering, the solder joint state that meets the requirements is finally formed. This preparation method mainly relies on the operator's skill control, but the overall process of preparing high-voltage solder joints is time-consuming and inefficient.

[0004] The second method is for straight-rod terminal components mentioned in patent CN 118848145A. By putting a limit sleeve on the terminal according to the actual length and wetted length of the device terminal, the welding position is limited; combined with the wire end processing and the control of the welding angle and the amount of solder, reliable welding of high-voltage solder joints is achieved. This preparation method still mainly relies on manual methods, and has the same problems of long time consumption and low efficiency as the first preparation method.

[0005] The third method is mentioned in patent document CN 108581110B, which is to tin the pins of the components and install them on the printed circuit board, apply solder paste on the pads of the high-voltage solder joint pins, and then install them on a three-axis mobile platform. The energy of the laser beam is transferred to the pin solder joints, and the solder spontaneously melts into liquid state after receiving heat. The liquid solder fills the gaps between the through holes in the pads and the pins to form high-voltage solder joints. This preparation method is better to use laser equipment instead of manual methods, but the laser welding process can only heat and weld the solder joints one by one, and it is impossible to heat the welding object as a whole to achieve fast and batch welding.

[0006] The above-mentioned prior arts are unable to achieve successful one-time batch welding of high-voltage solder joints of lead wires of high-voltage components. Summary of the invention

[0007] The technical problem solved by the present application is: to overcome the deficiencies of the prior art and provide a method for welding high-voltage solder joints of component lead wires in batches by utilizing equipment, thereby achieving the purpose of successful one-time batch welding of high-voltage solder joints of high-voltage component lead wires, solving the problems of difficulty and low efficiency of manual control in the manual welding process and long time of heat influence caused by secondary tinning of the product, thereby greatly improving the reliability of the high-voltage solder joints.

[0008] This application solves the problem of narrow heat transfer area and low welding efficiency in one-time heat transfer using traditional manual welding or laser welding; it covers aspects such as lead wire end processing preparation, tooling and mold design and installation, solder quantification control, and equipment welding.

[0009] The technical solutions provided by this application are as follows:

[0010] A structure capable of batch-preparing lead wire high-voltage solder joints, used for preparing solder joints between lead wires and component pins connected to TO package components, comprising a solder joint tooling mold, wherein the solder joint tooling mold comprises an upper mold and a lower mold;

[0011] A groove is provided on one side of the upper mold and the lower mold, and the groove sides of the upper mold and the lower mold are opposite to form a welding spot welding area;

[0012] The lead wires and the parts where the pins of the components need to be welded are pre-fixed to obtain the parts to be welded;

[0013] The upper mold and the lower mold are provided with a first slot and a second slot at the edge positions of the opposite sides, the lead wire is inserted into the first slot facing the lead wire, and the pin of the component is inserted into the second slot facing the lead wire, so that the part to be welded is located in the welding area of ​​the welding spot, and the other ends of the lead wire and the pin of the component are located outside the welding spot tooling mold;

[0014] A solder inflow hole is provided on one side surface of the upper mold, and the solder inflow hole is connected to the solder spot welding area. The molten solder flows into the solder spot welding area through the solder inflow hole and forms a solder spot after cooling.

[0015] Through the above structure, batches of high-voltage component lead wires can be installed between the corresponding upper mold and lower mold, and by flowing solder into the solder inlet hole to fill the solder joint welding area, one-time batch welding of the high-voltage solder joints of the high-voltage component lead wires can be achieved.

[0016] Furthermore, a solder pre-storage area is provided on one side of the upper mold, the solder pre-storage area is located above the solder spot welding area, and the solder inflow hole connects the bottom of the solder pre-storage area and the solder spot welding area.

[0017] Furthermore, it also includes a fixed base plate, and the TO package components and the lower mold are both detachably connected to a side surface of the fixed base plate.

[0018] Furthermore, the surface of the fixed base plate is respectively provided with a mold limiting groove and a device limiting groove, the bottoms of the mold limiting groove and the device limiting groove are in the same horizontal plane, the lower mold is installed in the mold limiting groove, the TO packaged components are installed in the device limiting groove, and the TO packaged components and the lower mold are fixed to the fixed base plate by high temperature resistant tape or a pressure plate.

[0019] Furthermore, when the lead wires and component pins are interconnected in opposite directions, one end of the lead wires is overlapped with the end of the component pins, and the other end of the lead wires extends in a direction away from the TO packaged component; the first card slot and the second card slot are located on opposite sides of the upper mold and the lower mold, and the lead wires and the component pins extend from opposite sides of the solder joint tooling mold through the first card slot and the second card slot respectively, and the solder joint tooling mold is sealed with the lead wires at the first card slot position, and the solder joint tooling mold is sealed with the component pins at the second card slot position; the solder pre-storage area is arranged on the side of the upper mold away from the lower mold; a solder inflow hole is arranged at the lowest point of the bottom of the solder pre-storage area.

[0020] Furthermore, a side solder inlet hole is arranged on each side of the solder inlet hole at the lowest point of the bottom, and the distance from the end of the side solder inlet hole away from the solder spot welding area to the solder spot welding area is greater than the distance from the end of the solder inlet hole at the lowest point of the bottom away from the solder spot welding area to the solder spot welding area, and the volume of the melted solder will not completely cover the end of the side solder inlet hole.

[0021] Furthermore, when the lead wires and component pins are interconnected in the same direction, one end of the lead wire is aligned with the end of the component pin, and the other end of the lead wire extends toward the TO packaged component; a groove is provided on the end face of the upper mold close to the component body as a solder pre-storage area, the solder joint welding area is directly connected with the solder pre-storage area, and there is a slope at the bottom of the solder pre-storage area that tilts downward toward the solder joint welding area.

[0022] Furthermore, the end face of the TO packaged component connected to the component pin has the end face of the component insulator, and the distance d3 between the solder joint end face and the component insulator end face is not less than 2 mm;

[0023] The distance d1 between the insulation layer of the lead wire and the welding point shall not exceed 1 times the lead wire diameter d;

[0024] The shortest distance d2 between the lead wire and the end of the component pin and the inner wall of the groove of the upper mold and the lower mold is not less than 0.5mm.

[0025] A method for batch-preparing high-voltage solder joints for lead wires, using any of the above structures for batch-preparing high-voltage solder joints for lead wires, comprising:

[0026] S1. Cut the pins of the components to a suitable length and then tin them. Remove the insulation layer of one end of the lead wire and tin it. Use a fine core wire to wrap the lead wire and the component pins to pre-fix them.

[0027] S2, cover the upper mold and the lower mold on the outside of the pre-fixed wire lead wires and component pins, and connect the lower mold and the TO package components to the fixed bottom plate;

[0028] S3, filling the solder into the solder pre-storage area to obtain the assembly to be soldered;

[0029] S4. Place the components to be welded into the equipment and perform integral heat transfer welding according to the set temperature curve.

[0030] Furthermore, in S3, the filling volume of the solder is V5=V1-V2-V3-V4, wherein V1 is the volume of the soldering area of ​​the solder joint, V2 is the volume of the lead wire in the solder joint tooling mold, V3 is the volume of the component pin in the solder joint tooling mold, and V4 is the volume of the thin core wire; the solder weight M=V5*ρ, wherein ρ is the density of tin-lead solder.

[0031] In summary, this application at least includes the following beneficial technical effects:

[0032] The method for batch preparation of high-voltage solder joints provided by the present invention achieves the beneficial effect of being able to successfully weld the high-voltage solder joints of the lead-out wires of high-voltage components in one batch through an overall heat transfer method for the welding object in the equipment area, thereby solving the problems of difficulty and low efficiency of manual control in the manual welding process and long time of heat influence caused by secondary tinning of the product, and greatly improving the reliability of the high-voltage solder joints. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is an appearance diagram of a high-voltage solder joint prepared by interconnecting wires with wires using Example 1 of the present invention;

[0034] Figure 2 is a cross-sectional view of a high-voltage solder joint prepared by interconnecting wires with wires using Example 1 of the present invention;

[0035] Figure 3 This is an appearance diagram of a high-voltage solder joint prepared when a TO power tube and a wire are interconnected oppositely using Example 2 of the present invention;

[0036] Figure 4 It is a cross-sectional view of preparing a high-voltage solder joint when a TO power tube and a wire are interconnected oppositely using Example 2 of the present invention;

[0037] Figure 5 This is an appearance diagram of a high-voltage solder joint prepared by interconnecting a 3TO power tube and a wire in the same direction using an embodiment of the present invention;

[0038] Figure 6 It is a cross-sectional view of preparing a high-voltage solder joint when a 3TO power tube and a wire are interconnected in the same direction using an embodiment of the present invention;

[0039] Figure 7 This is an appearance diagram after batch installation using a solder joint tooling mold when the TO power tube and the wire are interconnected in opposite directions using the implementation example 2 of the present invention;

[0040] Figure 8 This is an appearance diagram after batch installation using a solder joint tooling mold when the TO power tube and the wire are interconnected in the same direction using the implementation example 2 of the present invention.

[0041] Explanation of the reference numerals: 1. wire lead; 2. component pin; 21. TO package component; 3. upper mold; 4. lower mold; 5. solder inflow hole; 6. fixed base plate; 7. solder pre-storage area; 8. solder joint welding area. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the present application more clear, the implementation methods disclosed in the present application will be further described in detail below in conjunction with the accompanying drawings.

[0043] The present application embodiment discloses a structure for batch production of lead wire high voltage welding points, such as Figure 1 , Figure 2 and Figure 3 As shown, it is used to prepare a high-voltage solder joint between a lead wire 1 and a component pin 2 connected to a TO package component 21, and includes a fixed base plate 6, an upper mold 3 and a lower mold 4.

[0044] One side surface of the upper mold 3 and the lower mold 4 is provided with grooves, and the groove sides of the upper mold 3 and the lower mold 4 form a solder joint welding area 8; the parts of the wire lead 1 and the component pin 2 to be welded are pre-fixed to obtain the parts to be welded; the upper mold 3 and the lower mold 4 are provided with a first card slot and a second card slot at the edge positions of the opposite sides, the wire lead 1 is inserted into the first card slot opposite, and the component pin 2 is inserted into the second card slot opposite, so that the part to be welded is located in the solder joint welding area 8, and the other ends of the wire lead 1 and the component pin 2 are located outside the solder joint tooling mold.

[0045] A solder pre-storage area 7 and a solder inflow hole 5 are provided on one side surface of the upper mold 3. The solder pre-storage area 7 is located above the solder spot welding area 8. The solder inflow hole 5 connects the bottom of the solder pre-storage area 7 and the solder spot welding area 8. The molten solder flows into the solder spot welding area 8 through the solder inflow hole 5 and forms a solder spot after cooling.

[0046] The TO packaged component 21 and the lower mold 4 can be detachably connected to one side surface of the fixed base plate 6. Specifically, the bottom of the TO packaged component 21 and the lower mold 4 are placed in close contact with the fixed base plate 6, and then fixed with a high temperature resistant tape or other pressing plate. Specifically, the surface of the fixed base plate 6 is respectively provided with a mold limiting groove and a device limiting groove, and the bottoms of the mold limiting groove and the device limiting groove are in the same horizontal plane, the lower mold 4 is installed in the mold limiting groove, and the TO packaged component 21 is installed in the device limiting groove.

[0047] The connection between the wire lead 1 and the component pin 2 includes opposite-direction interconnection and same-direction interconnection.

[0048] like Figure 1 , Figure 4 and Figure 7 As shown, the opposite interconnection is: one end of the wire lead 1 is overlapped with the end of the component pin 2, and the other end of the wire lead 1 extends in the direction away from the TO package component 21. At this time, the first card slot and the second card slot are located on the opposite sides of the upper mold 3 and the lower mold 4, and the wire lead 1 and the component pin 2 extend from the opposite sides of the solder joint tooling mold through the first card slot and the second card slot respectively, and the solder joint tooling mold is sealed with the wire lead 1 at the first card slot position, and the solder joint tooling mold is sealed with the component pin 2 at the second card slot position; the solder pre-storage area 7 is set on the side of the upper mold 3 away from the lower mold 4, and the solder can enter the solder joint welding area 8 through the solder inflow hole 5 after being heated and melted, wherein the middle bottom position of the solder pre-storage area 7 A solder inflow hole must be designed. Considering that the internal air will be squeezed out when the molten solder enters the solder joint welding area 8, two solder inflow holes are added on both sides of the solder inflow hole in the middle of the solder pre-storage area 7 for air discharge. The distance from the ends of the two solder inflow holes away from the solder joint welding area 8 to the solder joint welding area 8 is greater than the distance from the ends of the solder inflow holes in the middle to the solder joint welding area 8, and the volume of the melted solder will not completely cover the ends of the two solder inflow holes, ensuring the continuous discharge of air. When welding, the bottom plate 6 is fixed horizontally, and the solder pre-storage area 7 is located directly above the solder joint welding area 8.

[0049] like Figure 5 , Figure 6 and Figure 8As shown, the same-direction interconnection is: one end of the wire lead 1 is aligned with the end of the component pin 2, and the other end of the wire lead 1 extends in the direction close to the TO package component 21. At this time, the same sealing method as the opposite-direction interconnection can be adopted, but because the outer insulation layer of the wire lead 1 is a soft material, and the component pin 2 is a hard metal, the soft and hard end faces need to be sealed by the upper mold 3 and the lower mold 4, which is difficult. In addition, considering that the number of wire lead wires may be more than one in the production process, or the size difference with the component pin 2 is large, the sealing of the end faces of the wire lead 1 and the component pin 2 is more difficult. Therefore, when welding, the lower mold 4 and the TO packaged component 21 are placed vertically after being fixed on the bottom plate 6, and a groove is designed on the end face of the upper mold 3 close to the component body as a solder pre-storage area 7. The solder joint welding area 8 is directly connected with the solder pre-storage area 7. There is a slope at the bottom of the solder pre-storage area 7 that tilts downward in the direction of the solder joint welding area 8. This can ensure that after the solder melts, it can directly flow into the solder joint welding area 8 along the side wall of the groove of the upper mold 3, and at the same time, it helps the internal air to be discharged into the solder joint welding area 8 close to the side wall of the groove of the lower mold 4. At this time, there is no need to design a solder inlet hole 5.

[0050] The present application also discloses a method for batch preparing high-voltage solder joints of lead wires, which mainly includes the following steps:

[0051] Step (I), preparation: if necessary, first cut the component pin 2 to a suitable length, then tin the cut component pin 2, then prepare the wire of the required length as the wire lead 1, then process the end of the wire lead 1, and then tin the lead. You can use a fine core wire to wrap the wire lead 1 and the component pin 2 for pre-fixation, wrap the core wire 3 to 5 times, the distance d3 between the end face of the solder joint and the end face of the component insulator is not less than 2mm, the smaller the distance d1 between the insulation layer of the wire lead 1 and the solder joint, the better, generally not more than 1 times the lead diameter d;

[0052] Step (ii), design and installation of solder joint tooling: according to the state of the lead wire and the component pin after winding, design a high-voltage solder joint welding tooling that can cover the area to be welded, and then put the selected welding tooling on the component pin and the lead wire to confirm that the tooling is well sealed at the end surface;

[0053] Step (iii), quantitative calculation of solder required for high-voltage solder joints: Based on the volume V1 of the solder joint tooling mold, the volume V2 of the lead wire in the solder joint tooling mold, the volume V3 of the pin solder joint tooling mold, and the volume V4 of the winding core wire, the required solder volume V5 = V1-V2-V3-V4 can be calculated, and the required solder weight M = V5*ρ (ρ is the density of tin-lead solder, 8.4g / cm 3 );

[0054] Step (IV), temperature curve confirmation: In order to ensure that the solder of subsequent products can be reliably melted through the equipment to form solder joints, the temperature curve needs to be confirmed according to the equipment requirements;

[0055] Step (V), solder filling: prepare the required volume V5 according to the quantitative calculation of solder and fill it into the solder joint tooling mold;

[0056] Step (six), soldering: Place the product to be welded filled with solder into the equipment, and then perform integral heat transfer welding according to the previously confirmed temperature curve.

[0057] The solder type is one or any combination of tin-lead eutectic solder, tin-silver-copper solder, and lead-free solder; the solder state is one or any combination of solder paste, tin wire, tin block, and tin sheet;

[0058] The solder joint tooling mold material is synthetic stone, Kovar alloy, aluminum alloy or a stable material that can withstand high temperatures and does not react with solder.

[0059] The inner surface of the solder joint tooling mold needs to be continuous, smooth, without protrusions or depressions. The inner edge of the mold cannot contact the component pins and lead wires, and the distance d2 from each end face is generally not less than 0.5mm;

[0060] The shape of the welding area of ​​the welding spot tooling mold can be designed according to needs, oval, olive, spherical, date or any other shape.

[0061] The equipment is one of a reflow oven, a vacuum reflow oven, a vacuum vapor phase soldering oven, an infrared rework station, and a hot air rework station.

[0062] Example 1: Preparation of high-voltage solder joints for interconnecting wires

[0063] The materials, tooling and equipment used include 0.3mm thick Sn63Pb37 solder sheets, AF-25019×0.12mm high temperature resistant wires, aluminum alloy solder joint tooling molds (including upper mold parts and lower mold parts), temperature-controlled tin pots, synthetic stone fixed base plates, reflow ovens, and analytical balances (with an accuracy of 0.0001g).

[0064] Step (i), cut a certain length of wire AF-250 19×0.12mm (core wire diameter ~ 0.6mm) as required, use a heat stripper to process the wire end, and then tin it with a tin pot. If necessary, use a single core wire length l of AF-250 19×0.12mm wire with a length of 10mm to wrap the wires with each other for 3 to 5 turns for pre-fixation;

[0065] Step (ii), according to the state of the wire after winding, a high-voltage welding spot welding tooling mold that can cover the area to be welded is designed and processed by using aluminum alloy, the inner wall of the mold is flush with the insulation layer of the wire, that is, d1 is 0 mm, the distance d2 between the inner wall of the mold welding area and the end face of the wire is 0.5 mm, and the length L of the wire in the welding area of ​​the tooling mold welding spot is 10 mm;

[0066] Step (three), such as Figure 2 As shown in the figure, the volume V1 of the solder joint area is directly obtained based on the solder joint tooling mold model, which is 35.640mm 3 , The volume of the wire in the welding area of ​​the welding point tooling mold V2=V3=S*L=πR 2 *L=3.14*0.6 2 *10=11.304mm 3 , winding core volume V4 = s * l = πr 2 *l=3.14*0.06 2 *10=0.113mm 3 , then the required solder volume V5 = V1-V2-V3-V4 = 35.640-11.304-11.304-0.113 = 12.919 mm 3 Finally, the required solder weight is M = V5*ρ = 12.919*10 -3 *8.4=0.11g, cross-sectional diagram as shown Figure 2 As shown;

[0067] Step (IV): Figure 1 The components to be soldered shown are in accordance with the requirements of the reflow oven equipment. A thermocouple is used to confirm that the temperature of the solder joint welding area in the tooling mold meets the reflow requirements, and the usable temperature curve is confirmed, and then the components to be soldered are taken out;

[0068] Step (V), using an analytical balance to weigh the Sn63Pb37 solder sheet with a thickness of 0.3 mm calculated in step (C), and then loading it into the solder pre-storage area of ​​the upper mold;

[0069] Step (six), sending the soldered component to be soldered into a reflow soldering device, and then performing integral heat transfer soldering according to the previously confirmed temperature curve;

[0070] Step (VII): After reflow soldering, the interconnect solder joints are inspected to be full and rounded in shape, without protrusions, apexes, or sharp edges.

[0071] Example 2: Preparation of high-voltage solder joints when a TO power tube is interconnected with a wire

[0072] The materials, tooling and equipment used include Alpha OL-107E solder paste (No. 3 powder, metal content ratio 90%), AF-250 19×0.12mm high temperature resistant wire, TO254 power tube (pin diameter 1mm), aluminum alloy solder joint tooling mold (including upper mold part and lower mold part), temperature controlled tin pot, synthetic stone fixed base plate, reflow oven, and analytical balance (accuracy of 0.0001g).

[0073] Step (i), shorten the length of the TO254 power tube pin to 7mm, cut a certain length of wire AF-25019×0.12mm (core wire diameter ~ 0.6mm) as required, use a heat stripper to process the wire end, then tin the power tube pin and the wire with a tin pot, use the single core wire length l of the AF-250 19×0.12mm wire to be 10mm, and wrap the wire and the power tube pin in opposite directions for 3 to 5 turns for pre-fixation;

[0074] Step (ii), according to the state of the wire after winding, use aluminum alloy to design and process a high-voltage welding spot welding tooling mold that can cover the area to be welded, the inner wall of the mold is flush with the insulation layer of the wire, that is, d1 is 0mm, the distance d2 between the inside of the mold welding area and the end face of the wire is 0.5mm, the length L of the wire in the welding area of ​​the tooling mold welding spot is 5mm, and the distance d3 from the welding spot to the end face of the power tube is controlled to be not less than 2mm;

[0075] Step (iii): directly obtain the solder joint area volume V1 as 30.580 mm according to the solder joint tooling mold model 3 , The volume of the wire in the welding area of ​​the welding point tooling mold V2=S*L=πR 2 *L=3.14*0.6 2 *5=5.652mm 3 , the volume of the TO power tube pin in the welding area of ​​the solder joint tooling mold V3=S*L=πR 2 *L=3.14*1 2 *5=15.750mm 3 , winding core volume V4 = s * l = πr 2 *l=3.14*0.06 2 *10=0.113mm 3 , then the required solder volume V5 = V1-V2-V3-V4 = 30.580-15.750-5.652-0.113 = 9.065mm 3 , and the required solder weight is obtained as M = V5*ρ = 9.065*10 -3 *8.4=0.076g, and finally the required amount of solder paste is determined to be 0.076 / 0.9=0.084g according to the metal content ratio in the solder paste. The cross-sectional diagram is shown in Figure 4 As shown;

[0076] Step (IV): Figure 3 The components to be soldered shown are in accordance with the requirements of the reflow oven equipment. A thermocouple is used to confirm that the temperature of the solder joint welding area in the tooling mold meets the reflow requirements, and the usable temperature curve is confirmed, and then the components to be soldered are taken out;

[0077] Step (V), using an analytical balance to weigh the solder paste calculated in step (C), and then filling it into the solder pre-storage area of ​​the upper mold;

[0078] Step (six), sending the soldered component to be soldered into a reflow soldering device, and then performing integral heat transfer soldering according to the previously confirmed temperature curve;

[0079] Step (VII): After reflow soldering, the interconnect solder joints are inspected to be full and rounded in shape, without protrusions, apexes, or sharp edges.

[0080] Example 3: Preparation of high-voltage solder joints when TO power tubes and wires are interconnected in the same direction

[0081] The materials, tools and equipment used include Alpha OL-107E solder paste (No. 3 powder, metal content ratio 90%), AF-250 19×0.12mm high temperature resistant wire, TO254 power tube (pin diameter 1mm), Kovar alloy solder joint tooling mold (including upper mold part and lower mold part), temperature controlled solder pot, synthetic stone fixed base plate, and reflow oven.

[0082] Step (i), shorten the length of the TO254 power tube pin to 8mm, cut a certain length of wire AF-25019×0.12mm (core wire diameter ~ 0.6mm) as required, use a heat stripper to process the wire end, then tin the power tube pin and the wire with a tin pot, use the single core wire length l of the AF-250 19×0.12mm wire to be 10mm, and wrap the wire and the power tube pin in the same direction for 3 to 5 turns for pre-fixation;

[0083] Step (ii), according to the state of the wire after winding, use Kovar alloy to design and process a high-voltage welding spot welding tooling mold that can cover the area to be welded, the inner wall of the mold is flush with the insulation layer of the wire, that is, d1 is 0mm, the distance d2 between the inside of the mold welding area and the end face of the wire is 0.5mm, the length L of the wire in the welding area of ​​the tooling mold welding spot is 5mm, and the distance d3 from the welding point to the end face of the power tube is controlled to be not less than 2mm;

[0084] Step (iii): directly obtain the solder joint area volume V1 as 31.802 mm according to the solder joint tooling mold model 3 , The volume of the wire in the welding area of ​​the welding point tooling mold V2=S*L=πR 2 *L=3.14*0.62 *5=5.652mm 3 , the volume of the TO power tube pin in the welding area of ​​the solder joint tooling mold V3=S*L=πR 2 *L=3.14*1 2 *5=15.750mm 3 , winding core volume V4 = s * l = πr 2 *l=3.14*0.06 2 *10=0.113mm 3 , then the required solder volume V5 = V1-V2-V3-V4 = 31.802-15.750-5.652-0.113 = 10.287mm 3 , and the required solder weight is obtained as M = V5*ρ = 10.287*10 -3 *8.4=0.086g, and finally the required amount of solder paste is determined to be 0.086 / 0.9=0.096g according to the metal content ratio in the solder paste. The cross-sectional diagram is shown in Figure 6 As shown;

[0085] Step (IV): Figure 5 The components to be soldered shown are in accordance with the requirements of the reflow oven equipment. A thermocouple is used to confirm that the temperature of the solder joint welding area in the tooling mold meets the reflow requirements, and the usable temperature curve is confirmed, and then the components to be soldered are taken out;

[0086] Step (V), using an analytical balance to weigh the solder paste calculated in step (C), and then filling it into the solder pre-storage area of ​​the upper mold;

[0087] Step (six), sending the soldered component to be soldered into a reflow soldering device, and then performing integral heat transfer soldering according to the previously confirmed temperature curve;

[0088] Step (VII): After reflow soldering, the interconnect solder joints are inspected to be full and rounded in shape, without protrusions, apexes, or sharp edges.

[0089] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0090] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A structure capable of batch-producing high-voltage lead wire solder joints, used for producing solder joints between lead wires (1) and component pins (2) connected to TO package components (21), characterized in that: The welding point tooling mold comprises an upper mold (3) and a lower mold (4); A groove is provided on one side surface of the upper mold (3) and the lower mold (4), and the groove sides of the upper mold (3) and the lower mold (4) are opposite to each other to form a welding spot welding area (8); The lead wire (1) and the component pin (2) are pre-fixed at the locations to be welded to obtain the locations to be welded; The upper mold (3) and the lower mold (4) are provided with a first slot and a second slot at the edge positions of opposite sides, the lead wire (1) is inserted into the first slot facing the lead wire, and the component pin (2) is inserted into the second slot facing the lead wire, so that the part to be welded is located in the welding area (8) of the welding spot, and the other ends of the lead wire (1) and the component pin (2) are located outside the welding spot tooling mold; A solder inlet hole (5) is provided on one side surface of the upper mold (3), and the solder inlet hole (5) is connected to the solder spot welding area (8). The molten solder flows into the solder spot welding area (8) through the solder inlet hole (5) and forms a solder spot after cooling.

2. A structure capable of batch-producing lead wire high-voltage solder joints according to claim 1, characterized in that: A solder pre-storage area (7) is provided on one side of the upper mold (3), the solder pre-storage area (7) is located above the solder spot welding area (8), and the solder inflow hole (5) is connected to the bottom of the solder pre-storage area (7) and the solder spot welding area (8).

3. The structure for batch-producing high-voltage lead-out welding points according to claim 1, characterized in that: It also includes a fixed base plate (6), and the TO packaged components (21) and the lower mold (4) are both detachably connected to a side surface of the fixed base plate (6).

4. The structure for batch-producing high-voltage solder joints of lead wires according to claim 3, characterized in that: The fixed bottom plate (6) is provided with a mold limiting groove and a device limiting groove on its surface, respectively. The bottoms of the mold limiting groove and the device limiting groove are located at the same horizontal plane. The lower mold (4) is installed in the mold limiting groove. The TO package component (21) is installed in the device limiting groove. The TO package component (21) and the lower mold (4) are fixed to the fixed bottom plate (6) by means of a high temperature resistant adhesive tape or a pressing plate.

5. The structure for batch-producing high-voltage lead-out solder joints according to claim 1, characterized in that: When the lead wire (1) and the component pin (2) are interconnected in opposite directions, one end of the lead wire (1) overlaps the end of the component pin (2), and the other end of the lead wire (1) extends in a direction away from the TO package component (21); the first card slot and the second card slot are located on opposite sides of the upper mold (3) and the lower mold (4); the lead wire (1) and the component pin (2) extend from opposite sides of the solder joint tooling mold through the first card slot and the second card slot respectively, and the solder joint tooling mold is sealed with the lead wire (1) at the first card slot position, and the solder joint tooling mold is sealed with the component pin (2) at the second card slot position; the solder pre-storage area (7) is arranged on the side of the upper mold (3) away from the lower mold (4); and a solder inflow hole is arranged at the lowest point of the bottom of the solder pre-storage area (7).

6. The structure for batch-producing high-voltage solder joints of lead wires according to claim 5, characterized in that: A side solder inflow hole is arranged on each side of the solder inflow hole at the lowest point of the bottom, the distance from the end of the side solder inflow hole away from the solder spot welding area (8) to the solder spot welding area (8) is greater than the distance from the end of the solder inflow hole at the lowest point of the bottom away from the solder spot welding area (8) to the solder spot welding area (8), and the volume of the melted solder will not completely cover the end of the side solder inflow hole.

7. The structure for batch-producing high-voltage lead wire solder joints according to claim 1, characterized in that: When the lead wire (1) and the component pin (2) are interconnected in the same direction, one end of the lead wire (1) is aligned with the end of the component pin (2), and the other end of the lead wire (1) extends in a direction close to the TO package component (21); a groove is provided on the end surface of one side of the upper mold (3) close to the component body as a solder pre-storage area (7), the solder joint welding area (8) is directly connected to the solder pre-storage area (7), and a slope is provided at the bottom of the solder pre-storage area (7) that is inclined downward in the direction of the solder joint welding area (8).

8. The structure for batch-producing high-voltage solder joints of lead wires according to claim 1, characterized in that: The end face of the TO packaged component (21) connected to the component pin (2) has an end face of the component insulator, and a distance d3 between the end face of the solder joint and the end face of the component insulator is not less than 2 mm; The distance d1 between the insulation layer of the lead wire (1) and the welding point does not exceed 1 times the diameter d of the lead wire (1); The shortest distance d2 between the ends of the lead wires (1) and the component pins (2) and the inner walls of the grooves of the upper mold (3) and the lower mold (4) is not less than 0.5 mm.

9. A method for batch preparation of lead wire high voltage solder joints, characterized in that: The method is prepared using a structure capable of batch-producing high-voltage lead wire solder joints as described in any one of claims 1 to 8, comprising: S1, cutting the component pin (2) to a suitable length and then tinning it, removing the insulation layer of one end of the lead wire (1) and tinning it, and using a fine core wire to wrap the lead wire (1) and the component pin (2) to pre-fix them; S2, sleeve the upper mold (3) and the lower mold (4) onto the outside of the pre-fixed lead wires (1) and the component pins (2), and connect the lower mold (4) and the TO package component (21) to the fixed base plate (6); S3, filling solder into the solder pre-storage area (7) to obtain a component to be soldered; S4. Place the components to be welded into the equipment and perform integral heat transfer welding according to the set temperature curve.

10. A method for batch preparation of lead wire high voltage solder joints according to claim 9, characterized in that: In S3, the filling volume of the solder is V5=V1-V2-V3-V4, wherein V1 is the volume of the solder joint welding area (8), V2 is the volume of the lead wire (1) in the solder joint tooling mold, V3 is the volume of the component pin (2) in the solder joint tooling mold, and V4 is the volume of the thin core wire; the solder weight M=V5*ρ, wherein ρ is the density of tin-lead solder.

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