CN118201250A

CN118201250A - System and method for uniformly tin-plating two sides of circuit board patch and copper foil

Info

Publication number: CN118201250A
Application number: CN202410540082.2A
Authority: CN
Inventors: 何其三; 潘昭飞
Original assignee: Sunwin Hubei Optoelectronic Technology Co Ltd
Current assignee: Sunwin Hubei Optoelectronic Technology Co Ltd
Priority date: 2024-04-30
Filing date: 2024-04-30
Publication date: 2024-06-14

Abstract

The invention relates to the technical field of printed circuit board processing, in particular to a system and a method for uniformly tin-plating two sides of a circuit board patch and a copper foil, wherein the system comprises a printer, a chip mounter, a reflow soldering device, a jig for placing the circuit board and a horizontal conveying device for conveying the jig, the copper foil on the circuit board is provided with tin guide holes, and the area corresponding to the copper foil on the jig is hollowed out; the printing station, the surface mounting station and the reflow soldering station are sequentially arranged along the conveying direction of the horizontal conveying device, and the printing machine is arranged on the printing station and is used for printing solder paste on the surface mounting area and the copper foil on the circuit board; the chip mounter is arranged at the chip mounting station and is used for carrying out chip mounting on the chip mounting area; the reflow soldering device is arranged at the reflow soldering station and is used for reflow soldering of the circuit board. The invention can complete the surface mounting and tin coating by one-time reflow, and the fixture area below the copper foil is hollowed out, so that the fixture can not support the copper foil during reflow, the tin coating amount on the front and back surfaces of the copper foil can be uniform, and the fixture does not have the risk of tin adhesion or tin bead generation during reflow.

Description

System and method for uniformly tin-plating two sides of circuit board patch and copper foil

Technical Field

The invention relates to the technical field of printed circuit board processing, in particular to a system and a method for uniformly tin-plating two sides of a circuit board patch and a copper foil.

Background

At present, a plurality of flexible circuit boards are welded together by copper foils before being connected, so that quality problems such as copper foil falling, false soldering and the like caused by poor welding can be prevented in order to have good welding performance during welding, the copper foils can be plated with tin in advance, and meanwhile, other devices are arranged on the flexible circuit boards, and then a surface mounted device and tin plating can be synchronously carried out in an SMT process. The single-sided tin coating of the copper foil of the flexible circuit board is easier, and the double-sided tin coating cannot ensure the uniform tin coating amount of the two sides. In the prior art, a tin guide hole is generally formed in the middle of a copper foil, but solder paste overflows on a jig during printing, meanwhile, tin on the front side and the back side of reflow soldering is uneven, and part of copper foil contacts with the jig to cause heterochromatic rosin residues.

Disclosure of Invention

The invention aims to provide a system and a method for uniformly tin-plating both sides of a circuit board patch and a copper foil, which can ensure that the tin-plating amount of both sides of the copper foil is uniform during reflow soldering, and a jig has no risk of tin adhesion or tin bead generation.

In order to achieve the above purpose, the technical scheme of the invention is a system for uniformly tin-plating two sides of a patch and a copper foil of a circuit board, which comprises a printer, a chip mounter, a reflow soldering device, a jig for placing the circuit board and a horizontal conveying device for conveying the jig, wherein the copper foil on the circuit board is provided with tin guide holes, and the area corresponding to the copper foil on the jig is hollowed out; a printing station, a surface mounting station and a reflow soldering station are sequentially arranged along the conveying direction of the horizontal conveying device, and the printer is arranged on the printing station and is used for printing solder paste on the surface mounting area and the copper foil on the circuit board; the chip mounter is arranged at the chip mounting station and is used for carrying out chip mounting on the chip mounting area; the reflow soldering device is arranged at the reflow soldering station and is used for reflow soldering of the circuit board.

As one of the implementation modes, the printing station is also provided with a jacking mechanism, the jacking mechanism comprises a supporting plate and a driving assembly for driving the supporting plate to move up and down, the top surface of the supporting plate is provided with a plurality of jacking bulges, and the jacking bulges correspond to non-hollowed-out areas on the jig.

As one of the implementation modes, the top surface of the supporting plate is also provided with positioning protrusions, and the positioning protrusions are in one-to-one correspondence with and matched with the hollowed-out areas on the jig.

As one of the embodiments, the height of the positioning protrusion is equal to the sum of the height of the jacking protrusion and the thickness of the jig.

As one of the embodiments, the horizontal conveying device comprises two conveying lines which are arranged in parallel along the conveying direction, and two ends of the jig are respectively positioned on the two conveying lines; the jacking mechanism is arranged at the position between the two conveying lines corresponding to the printing station.

As one of the implementation modes, a top steel plate is arranged on the circuit board, and the top steel plate is connected with the jig through magnetic force adsorption; and a tin coating window is arranged on the top steel plate at the position corresponding to the surface mounting area and the copper foil.

As one of the implementation modes, a plurality of magnets are embedded on the top surface of the jig, and the magnets are connected with the top steel plate through magnetic attraction.

As one of the implementation modes, a plurality of first positioning holes are formed in the circuit board, a plurality of second positioning holes are formed in the top steel plate, a plurality of positioning columns are arranged on the jig, the positioning columns correspond to the first positioning holes and the second positioning holes one by one, and the positioning columns penetrate through the corresponding first positioning holes and the second positioning holes in sequence.

As one of implementation modes, a plurality of heat dissipation holes are formed in a non-hollowed-out area of the jig.

The invention also provides a method for uniformly tin-plating the two sides of the circuit board patch and the copper foil, which adopts the system for uniformly tin-plating the two sides of the circuit board patch and the copper foil, and comprises the following steps:

s1, placing a jig provided with a circuit board on a horizontal conveying device, driving the jig to move a printing station by the horizontal conveying device, jacking the jig upwards by a jacking mechanism, and printing solder paste on a patch area and a copper foil by the printing mechanism; after printing is finished, the jacking mechanism is retracted downwards, and the jig falls on the horizontal conveying device;

S2, the horizontal conveying device drives the jig to move to the surface mounting station continuously, and the surface mounting machine carries out surface mounting on the surface mounting area;

s3, the horizontal conveying device drives the jig to continue to move to a reflow soldering station, and the reflow soldering device performs reflow soldering on the circuit board.

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

(1) According to the invention, the copper foil of the circuit board is provided with the tin guide holes in advance, so that the front solder paste can overflow to the back surface during reflow; after the circuit board is placed on the jig, the front surface of the copper foil on the circuit board and the surface mounting area are firstly coated with solder paste, then elements are attached to the surface mounting area, and finally reflow soldering is carried out, so that the surface mounting and tin plating can be completed in one-time reflow, and the jig is not propped against the copper foil during reflow because the area of the jig below the copper foil is hollowed out, the tin plating amount on the front and back surfaces of the copper foil can be uniform, and meanwhile, the jig does not have the risk of tin sticking or tin beading during reflow;

(2) According to the invention, the jacking mechanism is arranged at the printing station, when the jig reaches the printing station, the jig is jacked up upwards through the jacking mechanism, and the positioning protrusions extend to the corresponding hollowed-out areas and support the circuit board, so that the distance between the circuit board and the printing template is ensured to be consistent in the printing process, the full and uniform printing tin amount is ensured, the shortage or non-uniformity of the printing tin amount is avoided, and the printing quality is improved.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a system for uniformly tin-plating two sides of a circuit board patch and a copper foil provided by an embodiment of the present invention;

fig. 2 is a schematic diagram of a circuit board according to an embodiment of the present invention;

Fig. 3 is a schematic diagram of an FPC on a circuit board according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a fixture according to an embodiment of the present invention;

fig. 5 is a schematic diagram of a lifting mechanism according to an embodiment of the present invention;

In the figure: 1. a printing machine; 2. a chip mounter; 3. a reflow soldering device; 4. a horizontal transfer device; 5. a circuit board; 6. an FPC; 7. copper foil; 8. a tin guide hole; 9. a patch area; 10. a first positioning hole; 11. a jig; 12. a hollowed-out area; 13. positioning columns; 14. a magnet; 15. a heat radiation hole; 16. a supporting plate; 17. lifting the bulge; 18. positioning the protrusion.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present invention and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.

The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second" may include one or more such features, either explicitly or implicitly; in the description of the invention, unless otherwise indicated, the meaning of "a number" is one or more than one.

As shown in fig. 1-4, the present embodiment provides a system for uniformly tin-plating two sides of a circuit board patch and a copper foil, which comprises a printer 1, a chip mounter 2, a reflow soldering device 3, a jig 11 for placing a circuit board 5, and a horizontal conveying device 4 for conveying the jig 11, wherein the copper foil 7 on the circuit board 5 is provided with a tin guide hole 8, and the area of the jig 11 corresponding to the copper foil 7 is hollowed out; a printing station, a surface mounting station and a reflow soldering station are sequentially arranged along the conveying direction of the horizontal conveying device 4, and the printer 1 is arranged on the printing station and is used for printing solder paste on the surface mounting area 9 and the copper foil 7 on the circuit board 5; the chip mounter 2 is arranged at the chip mounting station and is used for mounting the chip mounting area 9; the reflow soldering device 3 is disposed at the reflow soldering station, and is used for performing reflow soldering on the circuit board 5.

In the embodiment, the copper foil 7 of the circuit board 5 is provided with the tin guide holes 8 in advance, so that the front solder paste can overflow to the back surface during reflow; through the regional fretwork of corresponding copper foil 7 on the tool 11, lay circuit board 5 on the top surface of tool 11 on horizontal conveyer 4 after, copper foil 7 front and paster district 9 brush tin cream on circuit board 5 earlier, then paste the component in paster district 9, carry out reflow soldering at last, not only can once only backward flow accomplish paster and tin, the technological process has been simplified, production efficiency has been improved, and because copper foil 7 below tool 11 regional fretwork, therefore tool 11 can not withhold copper foil 7 during the backward flow, copper foil 7 just can be very even in the tin amount on the reverse both sides, tool 11 can not glue the tin cream during the backward flow simultaneously, also can not produce the tin pearl, defective products rate and maintenance cost in the production process have been reduced.

In this embodiment, each FPC 6 of the circuit board 5 has a plurality of copper foils 7, each copper foil 7 is provided with a plurality of tin guide holes 8, the number of the tin guide holes 8 on each copper foil 7 is determined according to the specific size and shape of the copper foil 7, as shown in fig. 3, each FPC 6 has four copper foils 7, two copper foils 7 are provided with two tin guide holes 8, and the other two copper foils 7 are provided with three tin guide holes 8. The position of each copper foil 7 corresponding to the circuit board 5 on the jig 11 is hollowed out, the range of each hollowed-out area 12 is not smaller than the corresponding size of the copper foil 7, each hollowed-out area 12 can be arranged independently of each other, and a plurality of hollowed-out areas 12 can be communicated to form a larger hollowed-out area 12.

In one embodiment, the printing station is further provided with a jacking mechanism, the jacking mechanism comprises a supporting plate 16 and a driving assembly for driving the supporting plate 16 to move up and down, a plurality of jacking protrusions 17 are arranged on the top surface of the supporting plate 16, and the jacking protrusions 17 correspond to the non-hollowed-out areas 12 on the jig 11. In this embodiment, the jacking protrusion 17 corresponds to the non-hollowed-out area 12 of the jig 11, so as to ensure that the jig 11 can be stably supported in the jacking process. The driving assembly can adopt a hydraulic cylinder, an air cylinder and the like, and can be specifically selected according to actual conditions; the driving assembly may be provided in plural and respectively lifting up four corners of the pallet 16, or may be provided in only one and lifting up the center of the pallet 16.

In one embodiment, the lifting protrusions 17 are plate-shaped or block-shaped, are arranged along the conveying direction of the jig 11, and are provided with two non-hollow areas 12 respectively used for supporting two ends of the jig 11, so as to ensure that the jig 11 can be stably supported and prevented from shaking or tilting. In another embodiment, the jacking protrusions 17 are columnar and are distributed in multiple ways, and are respectively used for supporting the non-hollowed-out areas 12 of different positions of the jig 11, so as to ensure that the jig 11 can be stably supported and provide more uniform supporting force.

According to the optimized embodiment, the top surface of the supporting plate 16 is further provided with positioning protrusions 18, and the positioning protrusions 18 are in one-to-one correspondence with and matched with the hollowed-out areas 12 on the jig 11. Further, the height of the positioning protrusion 18 is equal to the sum of the height of the lifting protrusion 17 and the thickness of the jig 11. When the jacking bulge 17 jacks up the jig 11, the top surface of the jacking bulge 17 jacks up the bottom surface of the jig 11, the positioning bulge 18 just stretches into the corresponding hollowed-out area 12, at the moment, the top surface of the positioning bulge 18 is flush with the top surface of the jig 11, the positioning bulge 18 can support the circuit board 5, the distance between the circuit board 5 and the printing template is ensured to be consistent in the printing process, the full and uniform printing tin amount is ensured, the shortage or non-uniform printing tin amount is avoided, and the printing quality is improved.

In one embodiment, a plurality of FPC units arranged in multiple rows and multiple columns are disposed on the circuit board 5, each FPC unit includes two FPCs 6, the positions of the circuit board 5 corresponding to the copper foils 7 are hollowed out, the FPCs 6 are in an L-shaped structure, the two FPCs 6 are obliquely disposed and buckled, as shown in fig. 2, copper foils 7 of the FPCs 6 on the left side of each row of FPC units are all on the same side, copper foils 7 of the FPCs 6 on the right side are all on the same side, rectangular hollowed-out areas 12 can be directly disposed on the jig 11 corresponding to the copper foil areas of each row of FPC units, adjacent rectangular hollowed-out areas 12 corresponding to the adjacent two rows of FPC units are communicated, as shown in fig. 4, at this time, positioning protrusions 18 are cuboid and are in one-to-one correspondence with the rectangular hollowed-out areas 12, and the sizes of the opposite positioning protrusions 18 are matched with the rectangular hollowed-out areas 12, as shown in fig. 5. In another embodiment, the jig 11 is provided with hollowed-out areas 12 corresponding to each copper foil 7 of each FPC 6 one by one, at this time, the positioning protrusions 18 are columnar and correspond to the hollowed-out areas 12 one by one, and the size and shape of the positioning protrusions 18 are matched with those of the hollowed-out areas 12.

In this embodiment, the horizontal conveying device 4 includes two conveying lines arranged in parallel along a conveying direction, and two ends of the jig 11 are respectively located on the two conveying lines; the jacking mechanism is arranged at the position between the two conveying lines corresponding to the printing station. Two ends of the jig 11 provided with the circuit board 5 are respectively positioned on two conveying lines, the two conveying lines synchronously drive the jig 11 to move, and when the jig 11 is conveyed to the printing station, the jacking mechanism jacks the jig 11 to leave the conveying lines. The conveyor line may be a belt conveyor line or a track conveyor line.

Further, a stop assembly is provided on the printer 1. Before the jig 11 is conveyed to the printing station, the stop component stretches out, and when the jig 11 is conveyed to the printing station, the jig 11 can be prevented from moving continuously; when the jacking mechanism jacks up the jig 11, the stop assembly is retracted. Specifically, the stop assembly may take the form of a stop block and a stop cylinder, the stop cylinder is fixed on the printing machine 1, the stop block is fixed on the movable end of the stop cylinder, and the stop block is driven to extend or retract by the stop cylinder.

Optimizing the embodiment, wherein a top steel plate is arranged on the circuit board 5, and the top steel plate is connected with the jig 11 through magnetic force adsorption; and a tin coating window is arranged on the top steel plate at the position corresponding to the patch area 9 and the copper foil 7. Wherein, the tinning window that patch district 9 corresponds and patch district 9 one-to-one and assorted, the tinning window that copper foil 7 corresponds and copper foil 7 one-to-one and assorted, printing machine 1 can be through tinning window to patch district 9 and copper foil 7 tinning on the circuit board 5. According to the embodiment, the circuit board 5 is clamped between the top steel plate and the jig 11, the top steel plate is connected with the jig 11 through magnetic force adsorption, so that the circuit board 5 can be prevented from shifting or shaking in the printing and pasting processes, the printing and pasting precision and quality are ensured, the top steel plate and the jig 11 can be fast and conveniently fixed together, and the circuit board 5 is convenient to take and pay off.

In one embodiment, a plurality of magnets 14 are embedded on the top surface of the jig 11, and the magnets 14 are connected with the top steel plate through magnetic attraction. Specifically, a groove is formed in the top surface of the jig 11, a magnet 14 is embedded in the groove, and the top surface of the magnet 14 is flush with the top surface of the jig 11, so that the circuit board 5 is placed conveniently; the magnets 14 may be arranged at intervals in the non-hollow areas 12 on the jig 11, as shown in fig. 4, or may be arranged only in the non-hollow areas 12 around the circuit board 5, so as to ensure stable fixation of the top steel plate and the jig 11.

Further, a plurality of first positioning holes 10 are formed in the circuit board 5, a plurality of second positioning holes are formed in the top steel plate, a plurality of positioning columns 13 are arranged on the jig 11, the positioning columns 13 correspond to the first positioning holes 10 and the second positioning holes one by one, and the positioning columns 13 sequentially penetrate through the corresponding first positioning holes 10 and the corresponding second positioning holes. Specifically, a first positioning hole 10 may be provided at least two corners of four corners of the circuit board 5, a positioning column 13 may be provided at a corresponding position on the jig 11, and a second positioning hole may be provided at a corresponding position on the top steel plate; optimally, the first positioning holes 10 are arranged at two corners of the diagonal corner of the circuit board 5, two positioning posts 13 are correspondingly arranged on the jig 11, and two second positioning holes are correspondingly arranged on the top steel plate.

In one embodiment, the non-hollowed-out area 12 of the jig 11 is provided with a plurality of heat dissipation holes 15. Because a large amount of heat can be generated in the reflow soldering process, in the embodiment, a plurality of heat dissipation holes 15 are distributed in the non-hollowed-out area 12 on the jig 11, so that the heat is rapidly dissipated, the circuit board 5 and the electronic element are prevented from being damaged by high temperature, and the soldering quality and the qualified materials are improved.

The embodiment also provides a method for uniformly tin-plating both sides of the patch and the copper foil 7 of the circuit board 5, wherein the system for uniformly tin-plating both sides of the patch and the copper foil of any one of the above is adopted, the copper foil 7 on the circuit board 5 is provided with a tin guide hole 8 in advance, and the area of the jig 11 corresponding to the copper foil 7 is hollowed out, and the method comprises the following steps:

S1, placing a jig 11 provided with a circuit board 5 on a horizontal conveying device 4, driving the jig 11 to move a printing station by the horizontal conveying device 4, jacking the jig 11 upwards by a jacking mechanism, and printing solder paste on a patch area 9 and a copper foil 7 by a printing mechanism 1; after printing is completed, the jacking mechanism is retracted downwards, and the jig 11 falls on the horizontal conveying device 4;

s2, the horizontal conveying device 4 drives the jig 11 to continue to move to a pasting station, and the pasting machine 2 carries out pasting on the pasting area 9;

s3, the horizontal conveying device 4 drives the jig 11 to continue to move to a reflow soldering station, and the reflow soldering device 3 performs reflow soldering on the circuit board 5.

Further, the following steps are included between step S1 and step S2: detecting the printed circuit board 5, identifying whether the printed circuit board 5 has poor printing or defects, and placing the printed circuit board 5 which is qualified in printing back on the horizontal conveying device 4 to continue the subsequent pasting operation; the printed off-board 5 is placed in a separate collection area.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.

Claims

1. A system for uniformly tin-plating two surfaces of a circuit board patch and a copper foil is characterized in that: the device comprises a printing machine, a chip mounter, a reflow soldering device, a jig for placing a circuit board and a horizontal conveying device for conveying the jig, wherein copper foil on the circuit board is provided with tin guide holes, and the area, corresponding to the copper foil, on the jig is hollowed out; a printing station, a surface mounting station and a reflow soldering station are sequentially arranged along the conveying direction of the horizontal conveying device, and the printer is arranged on the printing station and is used for printing solder paste on the surface mounting area and the copper foil on the circuit board; the chip mounter is arranged at the chip mounting station and is used for carrying out chip mounting on the chip mounting area; the reflow soldering device is arranged at the reflow soldering station and is used for reflow soldering of the circuit board.

2. The system for uniformly tin-plating both sides of a circuit board patch and a copper foil according to claim 1, wherein: the printing station is also provided with a jacking mechanism, the jacking mechanism comprises a supporting plate and a driving assembly used for driving the supporting plate to move up and down, a plurality of jacking protrusions are arranged on the top surface of the supporting plate, and the jacking protrusions correspond to non-hollowed-out areas on the jig.

3. The system for uniformly tin-plating both sides of a circuit board patch and a copper foil according to claim 2, wherein: the top surface of the supporting plate is also provided with positioning protrusions, and the positioning protrusions are in one-to-one correspondence with and matched with the hollowed-out areas on the jig.

4. The system for uniformly tin-plating both sides of a circuit board patch and a copper foil according to claim 3, wherein: the height of the positioning bulge is equal to the sum of the height of the jacking bulge and the thickness of the jig.

5. The system for uniformly tin-plating both sides of a circuit board patch and a copper foil according to claim 2, wherein: the horizontal conveying device comprises two conveying lines which are arranged in parallel along the conveying direction, and two ends of the jig are respectively positioned on the two conveying lines; the jacking mechanism is arranged at the position between the two conveying lines corresponding to the printing station.

6. The system for uniformly tin-plating both sides of a circuit board patch and a copper foil according to claim 1, wherein: a top steel plate is arranged on the circuit board and is connected with the jig through magnetic force adsorption; and a tin coating window is arranged on the top steel plate at the position corresponding to the surface mounting area and the copper foil.

7. The system for uniformly tin-plating both sides of a circuit board patch and a copper foil according to claim 6, wherein: the top surface of the jig is inlaid with a plurality of magnets, and the magnets are connected with the top steel plate through magnetic attraction.

8. The system for uniformly tin-plating both sides of a circuit board patch and a copper foil according to claim 6, wherein: be provided with a plurality of first locating holes on the circuit board, be provided with a plurality of second locating holes on the top steel sheet, be provided with a plurality of reference columns on the tool, the reference column first locating hole the second locating hole one-to-one, just the reference column runs through in proper order corresponding first locating hole with the second locating hole.

9. The system for uniformly tin-plating both sides of a circuit board patch and a copper foil according to claim 1, wherein: the non-hollowed-out area on the jig is provided with a plurality of heat dissipation holes.

10. A method for uniformly tin-plating two sides of a circuit board patch and a copper foil is characterized by comprising the following steps: a system for uniformly tin-plating both sides of a circuit board patch and a copper foil according to any one of claims 1 to 9, the method comprising the steps of: