CN111465183A

CN111465183A - PCB with flat welding spots and welding method

Info

Publication number: CN111465183A
Application number: CN202010235840.1A
Authority: CN
Inventors: 盛道学; 钟健; 刘玲
Original assignee: Ningbo Fulai Electronics Technology Co ltd
Current assignee: Ningbo Fulai Electronics Technology Co ltd
Priority date: 2020-03-30
Filing date: 2020-03-30
Publication date: 2020-07-28
Anticipated expiration: 2040-03-30
Also published as: CN111465183B

Abstract

The invention provides a PCB board with flat welding spots, which belongs to the technical field of printed circuit boards and comprises: the PCB is provided with a welding surface and an insert surface; the first pad is arranged on the surface of the plug-in unit and comprises a first inner disc body, a first outer disc body and a first heat-preservation spoke, and the first heat-preservation spoke is positioned in the plug-in unit overflow port; the plug connector is welded on the plug-in surface; the PCB welding method comprises the following steps: step 1, firstly, arranging a first bonding pad on a plug-in board surface; step 2, installing the plug connector on the PCB; step 3, loading the PCB into a welding machine fixture, spraying soldering flux to the welding surface, and then preheating the welding surface and performing wave soldering; and 4, concentrating the heat of soldering tin in the welding hole and between the plug connector and the plug connector surface by the first heat-insulating spoke and the second heat-insulating spoke. The invention has the beneficial effects that: the heat dissipation speed of the welding spot can be reduced, so that the welding spot is ensured to be smooth.

Description

PCB with flat welding spots and welding method

Technical Field

The invention belongs to the technical field of printed circuit boards, relates to a PCB with flat welding spots, and further relates to a welding method of the PCB.

Background

In the light subassembly of some cars, on some blind area auxiliary lamps or blind area detecting lamp especially, all can use the PCB board, and have the plug connector on the PCB board, so need weld, and when the welding, can produce convex welding point on the face of weld, lead to the face of weld unevenness.

In order to solve the defect of uneven welding points, a Chinese patent with application number of 201520247248.8 is existed at present, and a metal core PCB is disclosed, wherein all via holes with the aperture larger than or equal to 2mm on a metal core plate of the metal core PCB are non-metallized holes; at least two auxiliary holes are arranged on the hole ring of the via hole; the auxiliary holes are metallized holes, and the diameter of each auxiliary hole is far smaller than 2 mm.

In addition to the above PCB capable of flattening the solder joints, there is also a chinese patent with application number 201711364822.8, which discloses a PCB welding method, comprising the following steps: s1, forming a plurality of PCB grooves for placing PCBs on the surface of a fixed plate, wherein lead fixing tubes are arranged on the surface of the fixed plate; s2, fixing the PCB in the PCB groove on the fixing plate; s3, adding solder paste of a pad of a lead to be welded on the PCB; s4, placing the lead in the lead fixing tube on the fixing plate, wherein the welding end of the lead is contacted with a pad of the lead which is welded on the PCB in advance; s5, the fixing plate is subjected to reflow soldering, so that the lead is soldered on the PCB, and the soldering temperature is 150 ℃ and 250 ℃; and S6, taking the welded PCB out of the fixed board.

According to the PCB structure and the welding method, the defect that the welding spot of the traditional PCB structure is not smooth enough after welding is found, so that the actual welding spot of the PCB is protruded, and the actual design requirement cannot be met.

Disclosure of Invention

The invention aims to provide a PCB with flat welding spots and a welding method of the PCB aiming at the problems in the prior art.

The purpose of the invention can be realized by the following technical scheme: a PCB board with flat solder joints, comprising:

the PCB is provided with a welding surface and an insert surface, a welding hole is formed in the PCB, a welding opening and an insert opening are respectively formed in two ends of the welding hole, the welding opening is formed in the welding surface, and the insert opening is formed in the insert surface;

the first pad is arranged on the plug-in surface and comprises a first inner disc body, a first outer disc body and first heat preservation spokes, the first outer disc body is arranged on the plug-in surface, the first inner disc body is arranged in the plug-in opening, a plug-in overflow port is formed between the first inner disc body and the plug-in opening, two ends of the first heat preservation spokes are respectively connected with the first inner disc body and the first outer disc body, and the first heat preservation spokes are positioned in the plug-in overflow port;

the plug connector, its welding thereby on the plug-in components face with PCB board fixed connection, be provided with the pin on the plug connector, the pin passes first interior disk body and penetrates extremely in the welding hole.

Preferably, the PCB board is further provided with a positioning hole, the plug connector is provided with a positioning column, and the positioning column penetrates through the positioning hole.

The preferred still is in including setting up second pad on the face of weld, the second pad includes disk body, the outer disk body of second and the heat preservation spoke in the second, the outer disk body of second sets up on the face of weld, the disk body sets up in the second in the welding opening, and the disk body in the second with be formed with the welding overflow mouth between the welding opening, the both ends of the heat preservation spoke of second respectively with the disk body and the outer disk body of second are connected in the second, and the heat preservation spoke of second is located in the welding overflow mouth.

Preferably, the diameter of the pin is smaller than that of the welding hole, an overflow part surrounding the pin is arranged in the welding hole, and two ends of the overflow part are respectively connected with the welding overflow port and the plug-in overflow port.

Preferably, the welding overflow port and the plug-in overflow port are both in an annular structure, the first heat-preservation spokes are radially or explosively distributed on the plug-in overflow port, and the second heat-preservation spokes are radially or explosively distributed on the welding overflow port.

Preferably, the first bonding pad is of a windowing structure, and the second bonding pad is of a non-windowing structure.

Preferably, the length of the pin is smaller than the thickness of the PCB plate so as to prevent the pin from penetrating out of the welding hole.

Secondly, a PCB welding method is provided, which comprises the following steps:

step 1, firstly, arranging the first bonding pad on the plug-in surface to enable the first bonding pad to be positioned around the plug-in opening, and then arranging the second bonding pad on the welding surface to enable the second bonding pad to be positioned around the welding opening;

step 2, mounting the plug connector on the PCB, and enabling the pins to sequentially penetrate through the first inner disc body and the welding holes and penetrate into the second inner disc body;

step 3, the PCB is arranged in a welding machine clamp, soldering flux is sprayed on the welding surface, then the welding surface is preheated and subjected to wave soldering, so that high-temperature liquid tin enters the overflow part from the welding overflow port and then overflows from the plug-in piece overflow port, and the plug-in piece is welded on the plug-in piece surface by the soldering tin;

and 4, concentrating the heat of soldering tin among the welding holes, the plug connector and the plug connector surface by the first heat-preservation spoke and the second heat-preservation spoke, and reducing the heat dissipation speed of the soldering tin so as to avoid the cooling of welding spots to form salient points.

Preferably, in step 2, when the plug connector is plugged onto the plug connector surface, the positioning column is first inserted into the positioning block, so that the pins are fixed in the welding holes.

Preferably, in step 3, the pins are soldered on the first inner tray and the second inner tray by soldering tin.

Compared with the prior art, the invention has the beneficial effects that:

1. the solder can flow into between plug-in components face and the plug-in components from the plug-in components overflow mouth, and set up first heat preservation spoke after, can be when the PCB board crosses the stove absorbent heat concentrate on welding hole and plug-in components face to reduce the radiating rate of solder, avoid the solder joint cooling to form the bump, finally realize guaranteeing that the welding face is smooth.

2. When the locating column wears to establish in the locating hole, can make the plug connector fix on the suitable position of PCB board, simultaneously, the pin passes the welding hole, just so can make between plug connector and the PCB board when the welding keep fixed.

3. The first heat-preservation spokes and the second heat-preservation spokes are arranged in a radial mode and can also be understood as being arranged in an explosion mode, the arrangement mode of the spokes is very reasonable, the intervals among the spokes are even, the heat of the solder can be locked under the condition that the solder does not overflow to the surface of the plug-in unit, the cooling speed of the welding spots is greatly reduced, and once the heat dissipation speed of the solder in the welding holes is reduced, the convex spots cannot be formed at the welding spots.

4. The second pad adopts the structure of not windowing, so can reduce the area of contact of second pad and solder, the solder joint of welding open position is level and smooth, can not produce bellied problem.

5. When wave-soldering, liquid tin enters into the welding overflow mouth, then flows in on plug connector and plug-in components face from the plug-in components overflow mouth, and first heat preservation spoke and the cooperation of second heat preservation spoke this moment reduce the downthehole thermal loss of welding for heat when welding is concentrated between plug connector and plug-in components face, still concentrates on between the dish body in pin and first interior dish and the second, thereby avoids the solder joint cooling to form the bump.

Drawings

Fig. 1 is a schematic structural diagram of a PCB board with flat solder joints according to the present invention.

Fig. 2 is an enlarged schematic view of a portion a of fig. 1.

Fig. 3 is a schematic structural diagram of the surface of the insert of the present invention.

FIG. 4 is a schematic view of the structure of the bonding surface of the present invention.

FIG. 5 is a schematic diagram of the connection relationship between the PCB and the connector of the present invention.

Fig. 6 is a flowchart of a PCB board soldering method according to the present invention.

In the figure, 100, a PCB board; 110. welding a surface; 120. a plug-in face; 130. positioning holes; 200. welding the hole; 210. welding an opening; 211. welding an overflow port; 220. an insert opening; 221. an insert overflow port; 300. a first pad; 310. a first inner tray body; 320. a first outer tray body; 330. a first heat-preserving spoke; 400. a second pad; 410. a second inner tray body; 420. a second outer tray body; 430. a second insulating spoke; 500. a plug-in unit; 510. a pin; 520. and a positioning column.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

As shown in fig. 1, 2, 3 and 5, a PCB board having a flat pad includes: it should be noted here that, in the conventional PCB 100, although the plugging member is also soldered to the pad, the position of the soldering surface 110 may have a protruding solder point, which causes uneven solder points, intuitively, the soldering surface 110 of the PCB 100 may have a protruding solder point, and for some products, the surface requirement of the PCB 100 is higher, which does not allow an uneven structure to exist on the soldering surface 110 of the PCB 100, but the structure and the soldering method of the conventional PCB 100 may cause the soldering surface 110 of the PCB 100 to generate a protruding bump, which causes uneven solder surface 110.

In order to solve the above problem, first, the front and back surfaces of the PCB 100 are a soldering surface 110 and a socket surface 120, respectively, wherein the socket surface 120 is provided with circuits, various kinds of patches, and various kinds of elements, and the socket 500 is also fixed on the socket surface 120, and the soldering surface 110 is the reverse surface of the socket surface 120 and is used for contacting with solder during wave soldering.

The PCB 100 is provided with two welding holes 200, the number of the welding holes 200 is two, the welding holes 200 are mainly used for allowing the plug-in unit 500 to pass through and allowing the soldering tin to overflow from the welding surface 110 to the plug-in unit surface 120, two ends of the welding holes 200 are respectively provided with a welding opening 210 and a plug-in unit opening 220, the welding opening 210 is arranged on the welding surface 110, and the plug-in unit opening 220 is arranged on the plug-in unit surface 120; in short, the solder opening 210 and the insert opening 220 are actually two openings of the solder hole 200.

The first pad 300 is disposed on the package face 120, and the first pad 300 includes a first inner tray 310, a first outer tray 320, and first heat-insulating spokes 330, the first outer tray 320 is disposed on the package face 120, the first inner tray 310 is disposed in the package opening 220, a package overflow port 221 is formed between the first inner tray 310 and the package opening 220, both ends of the first heat-insulating spokes 330 are connected to the first inner tray 310 and the first outer tray 320, respectively, and the first heat-insulating spokes 330 are located in the package overflow port 221.

Preferably, the first bonding pad 300 is actually a package bonding pad located on the package face 120, the first bonding pad 300 is mainly used for being welded with the component pin 510, wherein the first outer tray 320 is used for being disposed on the plugging face and connected with the first inner tray 310 through the first heat-insulating spoke 330, the first inner tray 310 has a hole-like structure, so that the pin 510 of the package 500 can penetrate through the first inner tray 310 and penetrate into the welding hole 200, once the solder enters into the welding hole 200, the solder can weld the pin 510 and the first inner tray 310 together, and the first heat-insulating spoke 330 not only serves to connect the first inner tray 310, but also can form a certain blocking heat-insulating structure on the package overflow port 221, so as to perform a heat-insulating function.

It should be noted here that, since the plug-in opening 220 on the soldering hole 200 is larger than the first inner tray 310, a gap is formed between the two, i.e. the plug-in overflow port 221, solder can flow into the space between the plug-in surface 120 and the plug-in 500 from the plug-in overflow port 221, and after the first heat-preserving spoke 330 is provided, the heat absorbed when the PCB board 100 passes through the oven can be concentrated on the soldering hole 200 and the plug-in surface 120, and the heat dissipation speed of the solder is reduced, so as to avoid the formation of bumps due to the cooling of solder joints, and finally, the flatness of the soldering surface 110 is ensured.

The plug connector 500 is welded on the plug-in surface 120 and fixedly connected with the PCB 100, a pin 510 is arranged on the plug connector 500, and the pin 510 penetrates through the first inner disc body 310 and penetrates into the welding hole 200.

Preferably, the plug 500 is a component plugged on the PCB 100, and the number of the pins 510 is two, wherein the plug 500 is welded to the plug face 120, the pins 510 are inserted into the welding holes 200, and after welding, not only the plug 500 is welded to the plug face 120, but also the pins 510 are welded to the first inner tray 310 through solder.

As shown in fig. 1, 2, 3 and 5, in addition to the above embodiments, the PCB board 100 is further provided with a positioning hole 130, the plug connector 500 is provided with a positioning post 520, and the positioning post 520 is inserted into the positioning hole 130.

Preferably, since the plug 500 and the PCB 100 need to be positioned before soldering, otherwise the soldering effect is affected, the plug 500 needs to be matched with the positioning hole 130 through the positioning column 520, so as to fix the plug 500 on the PCB 100, and then soldering is performed.

Specifically, the positioning posts 520 are inserted into the positioning holes 130, so that the connector 500 is fixed on the PCB 100 at a proper position, and the pins 510 are inserted through the soldering holes 200, so that the connector 500 and the PCB 100 are fixed during soldering.

As shown in fig. 1, 2 and 4, in addition to the above embodiments, the second pad 400 is further included on the bonding surface 110, and the second pad 400 is actually a bonding pad and is disposed around the bonding opening 210.

The second bonding pad 400 includes a second inner disc body 410, a second outer disc body 420 and second heat-insulating spokes 430, the second outer disc body 420 is disposed on the bonding surface 110, the second inner disc body 410 is disposed in the bonding opening 210, a bonding overflow port 211 is formed between the second inner disc body 410 and the bonding opening 210, two ends of the second heat-insulating spokes 430 are respectively connected with the second inner disc body 410 and the second outer disc body 420, and the second heat-insulating spokes 430 are located in the bonding overflow port 211.

Preferably, the second bonding pad 400 is located around the soldering opening 210 on the soldering surface 110, the second bonding pad 400 is mainly used for being soldered with the component pin 510, wherein the second outer tray 420 is used for being disposed on the soldering surface 110 and connected with the second inner tray 410 through the second heat-insulating spoke 430, the second inner tray 410 has a hole-shaped structure, the pin 510 of the connector 500 can penetrate through the second inner tray 410, once the solder enters the soldering hole 200, the solder can solder the pin 510 and the second inner tray 410 together, the second heat-insulating spoke 430 not only plays a role of connecting the second inner tray 410, but also can form a certain blocking heat-insulating structure on the soldering overflow port 211, reduce the contact area with the solder, and ensure that the soldering point is flat and has no protrusion.

It should be noted here that, since the soldering opening 210 on the soldering hole 200 is larger than the second inner disc 410, a gap is formed between the two, that is, the soldering overflow port 211, the solder can flow into the soldering hole 200 from the soldering overflow port 211, and after the second heat-preserving spoke 430 is provided, the heat absorbed when the PCB 100 passes through the furnace can be concentrated in the soldering hole 200, and the heat dissipation speed of the solder is reduced, thereby preventing the solder joint on the soldering surface 110 from cooling to form a bump, and finally ensuring the soldering surface 110 to be flat.

As shown in fig. 1 and 2, in the above embodiment, the diameter of the pin 510 is smaller than the diameter of the welding hole 200, an overflow portion surrounding the pin 510 is provided in the welding hole 200, and both ends of the overflow portion are connected to the welding overflow port 211 and the insert overflow port 221, respectively.

Preferably, the diameter of the pin 510 is smaller than that of the soldering hole 200, so that there is an overflow part with a gap structure in the soldering hole 200, and the overflow part can be passed through by solder, specifically, solder flows into the overflow part from the soldering overflow port 211 and then flows out from the package overflow port 221 to the package surface 120, thereby achieving a soldering effect.

As shown in fig. 1, 2, 3 and 4, in the above embodiment, the welding overflow port 211 and the insert overflow port 221 are both in a ring structure, the first heat-insulating spokes 330 are radially or explosively distributed on the insert overflow port 221, and the second heat-insulating spokes 430 are radially or explosively distributed on the welding overflow port 211.

It should be noted here that the first heat-insulating spoke 330 and the second heat-insulating spoke 430 are similar in principle, and are both arranged on the overflow port, and reduce the heat dissipation speed by covering a part of the area of the overflow port, and lock the heat of the solder on the welding point, in addition, the first heat-insulating spoke 330 and the second heat-insulating spoke 430 can also prevent the welding point from deforming left and right, and because of the existence of the first and second heat-insulating spokes, and the spokes are arranged in a scattering or radial shape, the welding point can be blocked from protruding outwards, so that the welding surface is flat.

Preferably, in the actual structure, the welding overflow vent 211 and the insertion overflow vent which are at two ends of the overflow portion are both in an annular opening structure, and the first heat-insulating spokes 330 and the second heat-insulating spokes 430 are both radially arranged, similar to the spoke shape of a vehicle, and can also be understood as being arranged in an explosion shape, and the arrangement mode of the spokes is very reasonable, the intervals between the spokes are even, and the heat of the solder can be locked under the condition that the solder overflows to the insertion part surface 120, and the cooling speed of the welding point is greatly reduced, and once the heat dissipation speed of the solder in the welding hole 200 is reduced, a convex point cannot be formed at the welding point.

As shown in fig. 1, 2, 3, and 4, in the above embodiment, the first pad 300 has a structure of a window, and the second pad 400 has a structure of no window.

Preferably, the pad windowing and the pad non-windowing are actually the prior art, wherein the pad windowing is to shield the pad, and the pad is not to be windowed or shielded, and the second pad 400 is in a non-windowing structure, so that the contact area between the second pad 400 and the solder can be reduced, the solder joint at the position of the solder opening 210 is flat, and the problem of protrusion is avoided.

As shown in fig. 1 and 2, based on the above embodiment, the length of the pin 510 is smaller than the thickness of the PCB 100 so as to prevent the pin 510 from penetrating through the soldering hole 200.

Preferably, the soldering surface 110 of the PCB 100 needs to be flat and without bumps, so that the pins 510 cannot pass through the soldering holes 200, and the pins 510 are shortened, so that the soldering surface 110 does not have any bump structure after soldering.

As shown in fig. 1, 2, 3, 4, 5 and 6, on the basis of the above embodiments, a method for soldering a PCB 100 includes the following steps:

step 1, first, the first bonding pad 300 is disposed on the package surface 120 so that the first bonding pad 300 is located around the package opening 220, and then the second bonding pad 400 is disposed on the bonding surface 110 so that the second bonding pad 400 is located around the bonding opening 210.

Preferably, through step 1, the first pad 300 and the second pad 400 can be formed on the mating surface and the bonding surface 110, so that the pin 510 can be conveniently bonded with the two pads, and the first pad 300 and the second pad 400 can form the interposer overflow port 221 and the bonding overflow port 211 at the positions of the interposer opening 220 and the bonding opening 210, respectively, and the first heat-preserving spoke 330 and the second heat-preserving spoke 430 are arranged around the bonding hole 200, so that the heat-preserving effect can be achieved after the solder enters the bonding hole 200, the contact area between the solder and the air is reduced, and the heat dissipation speed is reduced.

Step 2, mounting the plug connector 500 on the PCB 100, so that the pins 510 sequentially pass through the first inner tray 310 and the welding holes 200 and penetrate into the second inner tray 410.

Preferably, before soldering, the pins 510 need to be inserted through the soldering holes 200, so that the pins 510 are soldered to the first inner tray 310 and the second inner tray 410, and the plug connector 500 is soldered to the plug surface 120 of the PCB 100.

And 3, loading the PCB 100 into a welding machine fixture, spraying soldering flux on the welding surface 110, preheating the welding surface 110, performing wave soldering, so that high-temperature liquid tin enters the overflow part from the soldering overflow port 211, and then overflows from the plug-in overflow port 221, so that the plug-in unit 500 is soldered on the plug-in unit surface 120 by the soldering tin.

Preferably, the PCB is required to be sent to a device for wave soldering, which is an existing soldering method, wherein the soldering surface 110 of the interposer is directly contacted with the high-temperature liquid tin to achieve the soldering purpose, the high-temperature liquid tin keeps an inclined surface, and the liquid tin forms a wave-like phenomenon by a special device, so the soldering method is called wave soldering.

And 4, the first heat-insulating spoke 330 and the second heat-insulating spoke 430 concentrate the heat of the soldering tin among the welding hole 200, the plug connector 500 and the plug-in part surface 120, and reduce the heat dissipation speed of the soldering tin so as to avoid the cooling of welding points to form salient points.

Preferably, during wave soldering, liquid tin enters the soldering overflow port 211 and then flows into the plug 500 and the plug face 120 from the plug overflow port 221, at this time, the first heat-preservation spoke 330 is matched with the second heat-preservation spoke 430, so that the loss of heat in the soldering hole 200 is reduced, the heat during soldering is concentrated between the plug 500 and the plug face 120 and between the pin 510 and the first inner tray body 310 and the second inner tray body 410, and thus the formation of bumps due to the cooling of the soldering points is avoided.

As shown in fig. 1, 2 and 6, in the above embodiment, when the plug 500 is inserted into the plug surface 120 in step 2, first, the positioning post 520 is inserted into the positioning block, so that the pin 510 is fixed in the soldering hole 200.

Preferably, the plug 500 needs to be fixed to the plug surface 120 before soldering, so that the plug 500 is fixed to the PCB 100, which can ensure the soldering effect.

As shown in fig. 1, 2 and 6, on the basis of the above embodiment, in step 3, the pins 510 are soldered to the first inner tray 310 and the second inner tray 410 by soldering, preferably, in addition to soldering the connectors 500 to the connector surface 120, the pins 510 are soldered to the first inner tray 310 and the second inner tray 410, and in the actual soldering process, the solder is introduced into the soldering holes 200 by wave soldering and overflows to the connector surface 120, so that the pins 510 and the connectors 500 are soldered at one time.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

Claims

1. A PCB board with level solder joint, its characterized in that includes:

2. The PCB board with flat solder joints of claim 1, wherein: still be provided with the locating hole on the PCB board, be provided with the reference column on the plug connector, the reference column wears to establish in the locating hole.

3. The PCB board with flat solder joints of claim 1, wherein: still including setting up second pad on the face of weld, the second pad includes disk body, the outer disk body of second and the heat preservation spoke of second in the second, the outer disk body of second sets up on the face of weld, the disk body sets up in the second in the welding opening, and the disk body in the second with be formed with the welding overflow mouth between the welding opening, the both ends of second heat preservation spoke respectively with the disk body and the outer disk body of second are connected in the second, and the heat preservation spoke of second is located in the welding overflow mouth.

4. A PCB board with flat solder joints according to claim 3, wherein: the diameter of the pin is smaller than that of the welding hole, an overflow part surrounding the pin is arranged in the welding hole, and two ends of the overflow part are respectively connected with the welding overflow port and the plug-in overflow port.

5. The PCB board with flat solder joints of claim 4, wherein: the welding overflow port and the plug-in components overflow port all are the loop configuration, first heat preservation spoke is radial or the explosive form distributes on the plug-in components overflow port, second heat preservation spoke is radial or the explosive form distributes on the welding overflow port.

6. A PCB board with flat solder joints according to claim 3, wherein: the first bonding pad is of a windowing structure, and the second bonding pad is of a non-windowing structure.

7. The PCB board with flat solder joints of claim 1, wherein: the length of the pin is smaller than the thickness of the PCB plate so as to prevent the pin from penetrating out of the welding hole.

8. A PCB welding method is characterized by comprising the following steps:

9. A method of soldering a PCB as claimed in claim 8, wherein: in step 2, when the plug connector is plugged on the plug connector surface, the positioning column penetrates through the positioning block, so that the pins are fixed in the welding holes.

10. A method of soldering a PCB as claimed in claim 8, wherein: in step 3, soldering tin welds the pins on the first inner tray body and the second inner tray body.