Background technology
Along with development of Communication Technique, printed circuit board (PCB) (Printed Circuit Board, PCB) integrated level is more and more higher, the function of chip is also more and more abundanter, and therefore, industry is also more and more higher to the welding requirements of connector on the printed circuit board (PCB), the welding of wishing connector can accomplish firmly, reliable, particularly,, need to guarantee the connector welding reliability especially as the independent current source module of outsourcing to some volumes, independent connector that quality is bigger.
Being fixed on the printed circuit board (PCB) by the mode of welding with power module is example, traditional solder technology mainly is the wave-soldering technology, as shown in Figure 1, the wave-soldering technology is with the solder bath of pumping action at the liquid solder that fusion is arranged, form the solder wave of given shape at the solder bath liquid level, plug-in mounting the printed circuit board (PCB) of connector place on the conveyer chain, pass the crest of solder wave with special angle and immersion depth, scolder enters in the through-holes of printed circuit boards, and the bottom surface of through-holes of printed circuit boards and the pin of power module are welded together.
In the welding process of reality, because volume, the pin of the connector that quality is bigger is also thicker, when welding, need more scolder to be fixed on it on printed circuit board (PCB) reliably, and the connector such as power module generally all is fixed on top surface of printed circuit board, and when utilizing traditional wave-soldering technology to be welded on connector on the printed circuit board (PCB), because the liquid solder of fusion is in the bottom surface of printed circuit board (PCB), in the effect of gravity and the restriction in power module encapsulation aperture, the scolder that can enter in the printed circuit board through-hole is less, the coupling part of connector and printed circuit board (PCB) mainly is the spot area that through hole bottom surface and connector pin form, it is the pad place of printed circuit board (PCB) bottom surface, make the welding of the pin of power module and printed circuit board through-hole inwall insufficient so probably, cause rosin joint, and then printed circuit board (PCB) is caused the hidden danger of reliability.In addition, in traditional wave-soldering process, the length of connector pin can not be too short, guarantees that pin can penetrate printed circuit board (PCB), just can make through hole bottom surface and connector pin form solder joint.And the thin and thick of printed circuit board (PCB) according to circumstances has difference, so just need customize the connector of different pin length at the beginning of PCB design according to the thickness of plate, has improved production cost.
Summary of the invention
The invention provides a kind of welding method and equipment of connector, be welded on reliability on the printed circuit board (PCB) to improve connector.
A kind of welding method of connector, this method comprises:
With the perforate of web plate and the pad alignment of printed circuit board top surface, and the contact placement, wherein, the position of each perforate of web plate relation is identical with the position relation of each pad of printed circuit board (PCB);
Perforate by web plate covers scolder in the through hole of the pad of printed circuit board (PCB) and pad, and removes web plate;
The pin of connector is inserted in the through hole of pad of printed circuit board (PCB), and carries out reflux operation.
A kind of welding equipment of connector, described equipment comprises:
Placement module is used for the perforate of web plate and the pad alignment of printed circuit board top surface, and the contact placement, and wherein, the position of each perforate of web plate relation is identical with the position relation of each pad of printed circuit board (PCB);
The scolder overlay module is used for by the perforate of web plate scolder being covered the pad of printed circuit board (PCB) and the through hole of pad;
Remove module, be used for after described scolder overlay module covers scolder the through hole of the pad of printed circuit board (PCB) and pad, removing web plate;
The plug-in mounting module is used for the pin of connector is inserted to the through hole of the pad of printed circuit board (PCB);
The backflow module is used for connector and printed circuit board (PCB) are carried out reflux operation.
The present invention covers the method for scolder in the pad of printed circuit board top surface and through hole by web plate, when making the pin of connector be inserted to the through hole of pad of printed circuit board (PCB), scolder can inwall attached to the pin of connector and through hole in, when carrying out reflux operation, owing to be coated with scolder on the end face pad, make in the process that scolder dissolves in heating, end face pad and connector pin form connection welding, simultaneously, owing to speckle with scolder on the through-hole wall of pad, therefore, in through hole, the pin of connector also can form connection welding with through-hole wall.Because connector and printed circuit board (PCB) have formed two place's connection welding at least, have improved welding reliability.
Embodiment
Below in conjunction with Figure of description the embodiment of the invention is believed description.
Printed circuit board top surface that relates in various embodiments of the present invention and bottom surface are respectively end face and bottom surfaces as shown in Figure 1.End face is meant the one side that does not immerse solder wave in traditional crest welding technology, promptly fixes the face at connector place to be welded among the present invention; The bottom surface is the one side that immerses solder wave in traditional wave-soldering technology, has connector pin to be welded in the bottom surface and passes, and also may not have connector pin to be welded to pass.
As shown in Figure 2, be the welding method steps flow chart schematic diagram of connector in the embodiment of the invention one, as can be seen from the figure this method may further comprise the steps:
Step 101: be the print circuit plates making web plate, the position of each perforate relation is identical with the position relation of pad in the printed circuit board (PCB) in the described web plate.
Web plate is a kind of auxiliary steel plate that is used for to the printed circuit board (PCB) solder-coating, and thickness is generally 0.12mm or 0.15mm.When being the one side design web plate of printed circuit board (PCB), quantity, position relation, shape and size according to this face pad of printed circuit board (PCB), a plurality of perforates on web plate, have been made, the quantity of this face pad of the quantity of these perforates and printed circuit board (PCB) is identical, the corresponding one by one pad of each perforate, that is: the position of each perforate relation is identical with the position relation of pad in the printed circuit board (PCB).The shape of perforate and size can be made according to the shape of pad, as shown in Figure 3, it is the vertical view of a printed circuit board top surface, as can be seen from Figure 3, the white portion of arrow indication is a pad 1, cingens black region is a through hole in the pad 1, therefore, with the shape and the area size of the corresponding web plate perforate of pad among Fig. 31 can be identical with the area size with the shape of pad 1, further, the area size that the area size design of the web plate perforate of pad 1 correspondence is become to be slightly larger than pad 1 is also passable, as the diameter of the web plate perforate of design can be than the diameter of corresponding bonding pad 1 big 3%-5%.
Step 102: the perforate of web plate is alignd with the pad of printed circuit board top surface, and contact is placed.
Before printed circuit board (PCB) and connector scolding tin, the web plate contact is placed on the top surface of printed circuit board, and the perforate on the assurance web plate is alignd one by one with the pad of printed circuit board (PCB).
Step 103: the perforate by web plate covers scolder in the through hole of the pad of printed circuit board (PCB) and pad.
In this step, the method that covers scolder in the through hole of pad and pad can have multiple, includes but not limited to following two kinds:
First method: solder coating back on web plate is wipeed off, because the alignment of the pad of the perforate of web plate and printed circuit board (PCB), therefore, scolder can cover the through hole of pad and pad by the perforate on the web plate.In order to make more scolder enter pad and through hole, can on web plate, repeated multiple times apply, wipe off scolder.
Second method: the perforate by web plate is poured into a mould scolder in the through hole of pad that aligns and pad.
Also should be noted that the covering amount of solder in this step, its algorithm can be as follows:
At first the through hole volume of pad is deducted the pin volume of the connector that inserts this through hole, obtain the volume after the solder solidification, and then the amount of contraction during according to volume after the solder solidification that obtains and solder solidification, determine the volume of solder of actual needs.For example, scolder has 50% amount of contraction when being transformed to solid by molten condition, and then the volume of solder of actual needs is exactly 2 times of volume after the solder solidification.
Step 104: connector is inserted to printed circuit board (PCB).
In this step, connector is inserted to printed circuit board (PCB), promptly allow the pin of connector be inserted in the through-holes of printed circuit boards, owing to all be coated with scolder at pad and through hole, therefore scolder will be by pin along being brought in the printed circuit board through-hole when pin inserts through hole, that is, on the inwall of the pin of connector and printed circuit board through-hole, all scolder can be arranged.If in thestep 103 on web plate the repeated multiple times solder-coating, then will have in this step in the inwall that more scolder enters printed circuit board through-hole.
Step 105: connector and printed circuit board (PCB) are carried out reflux operation.
Technique of backflow is to be coated to scolder (can be the soft fine scolder of paste) in the printed circuit board pads through hole by heat fused, realizes the pin of connector and the welding between the printed circuit board pads.In reflux operation, owing to be coated with scolder on the end face pad, make in the process that scolder dissolves in heating, end face pad and connector pin form connection welding, simultaneously, owing to speckle with scolder on the through-hole wall of pad, therefore, in through hole, the pin of connector also can form connection welding with through-hole wall, after carrying out reflux operation, connector and printed circuit board (PCB) have formed two place's connection welding at least.As shown in Figure 4, be the solder joint schematic diagram that carries out connector (being power module among Fig. 4) and printed circuit board (PCB) top layer pad after the reflux operation, owing at end face pad and through-hole wall connection welding being arranged all, therefore, welding reliability has improved greatly.
If the connector that relates in the present embodiment is a power module, because the pin of power module need carry bigger electric current, the pin of power module and the contact resistance between the through-hole wall are crossed conference and are caused bigger voltage drop, therefore, the pin of power module and the contact resistance between the through-hole wall are the smaller the better.And by after the welding method of present embodiment, the pin of power module forms pad with end face pad, through-hole wall respectively, has reduced touch voltage, has avoided bigger voltage drop, and power module is operated in the printed circuit board (PCB) better.
Step 106: connector and printed circuit board (PCB) are carried out the wave-soldering operation.
This step can be a preferred step, be used for the situation that the pin of connector can pass whole printed circuit board (PCB), by the operation of this step, formed the connection welding of connector pin and printed circuit board (PCB) bottom surface pad, further strengthened welding reliability.If the pin of connector can not penetrate printed circuit board (PCB), then do not need to carry out the operation of this step.
The embodiment of the invention two has also been put down in writing a kind of welding equipment of connector, be to belong to scheme under the same design with embodiment one, can be divided into module as shown in Figure 5 on the apparatus logic in the present embodiment two:placement module 11,scolder overlay module 12, removemodule 13, plug-inmounting module 14 andbackflow module 15, wherein:placement module 11 is used for the pad alignment with the perforate of web plate and printed circuit board top surface, and contact is placed, wherein, the position of each perforate of web plate relation is identical with the position relation of each pad of printed circuit board (PCB);Scolder overlay module 12 is used for by the perforate of web plate scolder being covered the pad of printed circuit board (PCB) and the through hole of pad;Removing module 13 is used for removing web plate after described scolder overlay module covers scolder the through hole of the pad of printed circuit board (PCB) and pad; Plug-inmounting module 14 is used for the pin of connector is inserted to the through hole of the pad of printed circuit board (PCB);Backflow module 15 is used for connector and printed circuit board (PCB) are carried out reflux operation.
Described equipment also comprises wave-soldering module 16, is used for connector and printed circuit board (PCB) bottom surface are carried out the wave-soldering operation; Volume ofsolder determination module 17 is used for the through hole volume of pad is deducted the pin volume of the connector that inserts this through hole, obtain the volume after the solder solidification, and the amount of contraction during according to volume after the solder solidification that obtains and solder solidification, determine the volume of solder of actual needs.
In the present embodiment, the logic module that each module can be made up of a plurality of plant equipment just can be that as shown in Figure 1 multiple plant equipment constitutes as wave-soldering module 16.Present embodiment does not limit the machinery of each module of composition and the mechanism of electronic equipment.
The method and apparatus that provides by the embodiment of the invention, can form connection welding at end face pad and connector pin, simultaneously can also form connection welding by the pin and the through-hole wall of connector, further, after the wave-soldering technology, can form the connection welding of connector pin and printed circuit board (PCB) bottom surface pad, improve welding reliability.In addition, when utilizing the present invention program to weld connector, do not need to consider the length of connector pin, for pin can not penetrate printed circuit board (PCB) than weak point connector, also can be welded on it on printed circuit board (PCB) reliably, reduce production cost, made the connector of same pin length can be applied to the printed circuit board (PCB) of different-thickness on the other hand, improved flexibility.
Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.