JPH0738243A - Method and apparatus for applying flux coating - Google Patents

Abstract

PURPOSE:To realize soldering of excellent quality by obtaining excellent pin contact properties even if a board is not cleaned in the case of soldering an electronic circuit board. CONSTITUTION:A method for coating with flux of different type comprises the step of coating components having different solderabilities with flux in the same board 21 of an electronic circuit by using a plurality of spray nozzles 25, 26 for flow-soldering the board 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering flux (post-flux) applying method and a flux applying apparatus in flow soldering of an electronic circuit board.

[0002]

2. Description of the Related Art Regarding the conventional flux application method of this type of flow soldering, there are a foaming method of applying with a foam formed by a foam tube and a method of applying with a spray type fluxer such as an air spray or an atomizer. There are two main types. In particular, in order to comply with recent CFC regulations, there are many cases where soldering is performed using a non-cleaning flux with a low solid content. In this case, the flux has a low viscosity, and it is not possible to form uniform bubbles by the foam tube. Therefore, a spray-type fluxer is indispensable. Further, as a non-cleaning method, a soldering method in which a conventional post flux having a relatively high solid content is uniformly applied by a spray type fluxer in a small amount has been put into practical use. Hereinafter, an example of the above-described conventional flux coating method will be described with reference to the drawings.

9 and 10 show perspective views of a conventional spray type fluxer, FIG. 9 shows a nozzle fixed type spray type fluxer, and FIG. 10 shows a nozzle drive type spray type fluxer. In FIG. 9, 1 is a solder substrate on which a capacitor 2, a connector terminal 3, and an IC 4 are mounted. 5
Is a spray nozzle, which is connected to the flux supply tube 6 and sprays the flux 7. In addition, 8 has shown the board | substrate conveyance direction.

In FIG. 10, 9 is a soldering board on which a capacitor 10, a connector terminal 11 and an IC 12 are mounted. A spray nozzle 13 is connected to the flux supply tube 14 and sprays the flux 15. The spray nozzle 13 is driven by a nozzle driving device 16. In addition, 17 is a board | substrate conveyance direction, 18 is a nozzle moving direction.

In FIG. 9, when the substrate 1 reaches the vicinity of the nozzle 5, the atomized flux 7 from the nozzle 5 is applied. At this time, spraying from the nozzle 5 may be continuously performed, but coating may be performed intermittently in order to facilitate control of the coating amount. Further, in order to improve the uniformity of the coating amount, a plurality of nozzles 5 may be arranged to perform coating.

In FIG. 10, when the substrate 9 reaches the vicinity of the nozzle 13, the nozzle 13 starts reciprocating movement in the direction of 18 by the nozzle driving device 16 and at the same time, starts to apply the atomized flux 15. This coating method is shown in FIG.
It is possible to improve the uniformity of the flux coating amount as compared with the above coating method.

[0007]

However, in the flux coating method having the above-mentioned structure, most of the flux used has a low solid content and low activity,
Flux residue is reduced and no cleaning is possible, but bridging defects tend to increase especially in soldering defects. Therefore, there is a demand for a soldering method that can eliminate the need for cleaning and that has less soldering defects.

In view of the above problems, the present invention provides a flux applying method which can realize no cleaning and reduce soldering failures in soldering in which a flux having a low solid content and a low activity is applied by a spraying device. A flux coating device is provided.

[0009]

A first object of the present invention is to provide a method of flow soldering an electronic circuit board, in which different spraying nozzles are used for different parts having different solderability within the same board surface. The flux is applied.

A second means for solving the problems of the present invention is a method of flow soldering of an electronic circuit board, in which fluxes are applied to parts having different solderability in the same board surface while changing the application amount of the flux. .

A third means of solving the problems of the present invention is to collect the parts having poor solderability as the electronic circuit board in the peripheral portion in the flow soldering of the electronic circuit board, and to secure the pin contact test land with the solderability. It is assumed that the electronic components are arranged around good parts and flux is applied to this electronic circuit board.

[0012]

According to the first means for solving the problems of the present invention, by the above-mentioned method, a portion where soldering failure is unlikely to occur in the same substrate surface (a portion where a chip resistor, a chip capacitor, a lead component having a rough pitch, etc. are mounted) For solid content,
Flux with a small amount of activator (for example, 0.5 to 10%) is applied, and the solid content and activator amount are applied to the part where soldering failure is likely to occur (the part where narrow-pitch lead parts are mounted). A large amount (for example, 5 to 20%) of flux is applied to reduce most of the flux residue on the substrate surface, improve the pin contact property by the in-circuit tester, and reduce the soldering failure of narrow pitch. You can

The second means for solving the problems of the present invention is to apply a predetermined amount of flux having a small solid content and a small amount of activator to a portion where soldering failure is unlikely to occur in the same substrate surface by the above method, By applying a flux of 1.5 to 3 times the predetermined amount to the part where soldering failure is likely to occur, most of the flux residue on the board surface is reduced, and the pin contact property by the in-circuit tester is improved. It is possible to improve and to reduce soldering defects of narrow pitch.

The third means for solving the problems of the present invention makes it possible to eliminate the cleaning of the substrate and improve the solderability by partially changing the flux coating amount, and even if a soldering failure occurs, it can be managed. And easy to modify.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A flux applying method according to a first embodiment of the present invention will be described below with reference to the drawings. 1 is a perspective view of a flux applying apparatus according to a first embodiment of the present invention, FIG. 2 is a plan view of a soldering surface of an electronic circuit board according to a first embodiment of the present invention, and FIG. 3 is a flow chart of flux applying, FIG. 4 is a functional explanatory diagram of the controller of the flux coating device.

In FIG. 1, reference numeral 21 is a soldering board on which a capacitor 22, a connector terminal 23 and an IC 24 are mounted. Reference numeral 25 is a spray nozzle for a low residue flux, and 26 is a spray nozzle for a flux having a larger solid content and a larger amount of activator than the low residue flux used in the spray nozzle 25. In the drawing, 27 is a flux supply tube of the spray nozzle 25, 28 is a flux supply tube of the spray nozzle 26, 26 is a spray-like flux,
30 is a substrate conveyance direction.

FIG. 2 shows the soldering surface of the substrate 21, showing the leads 22a of the capacitor, the lead portions 23a of the connector terminals (narrow pitch), the lead portions 24a of the IC, the chip parts 3, and the contacts. The test land 32 is exposed. In the figure, A is an area where soldering can be performed with a flux having a small amount of solid content and activator, B is an area where soldering failure often occurs when the amount of solid content and activator is not large, and C is the substrate transport direction.

FIG. 4 shows a coating device, which is a tank 33 of a flux 33a having a small amount of solids and an activator, and a flux 34a having a large amount of solids and an activator.
Tank 34, flux applying device main body 35, exhaust duct 36, soldering substrate 21, transport rail 38, solid content, spray nozzle 39 for flux with a small amount of activator,
Spray nozzle 4 for flux with a large amount of solids and activator
0, substrate detection sensor 41, flux controller 4
2. Atomization shape control valves 43 and 44, flux discharge valves 45 and 46, and a high pressure air supply source 47. In addition, 48 is a spray-like flux.

The operation of the first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3 and 4. As shown in FIG. 4, when the soldering board 21 is carried by the carrying rail 38 of the flux applying device 35 and reaches a predetermined position, the board detection sensor 41 detects the board and a predetermined time elapses based on the information. After that, the valves 44 and 46 are opened, and the flux 33a containing less solid content and less activator is added to the spray nozzle 3.
It is sprayed from 9 and applied to the substrate 21. The flux controller 42 is preliminarily input with the data of the dimension in the transport direction of the area A in which the solder can be soldered with a flux having a small solid content and a small amount of activator as shown in FIG. Later valves 44 and 46
Is closed and at the same time valves 43 and 45 are opened, and the flux containing a large amount of solids and activator is in the region B shown in FIG.
Applied to.

The substrate 21 on which the flux has been applied is subjected to flow soldering by jet soldering. When the substrate 21 is observed after that, the amount of residue in the area A is small and the soldering failure is small. Region B has a slightly large amount of residue but few soldering defects. In this substrate 21, the contact test lands 32, which causes a problem of pin contact failure when a large amount of residue is present, are arranged in the region A, and the narrow-pitch connector in which the bridge defect is less likely to occur is arranged in the region B. , Pin contact property even when the substrate 21 is not cleaned,
Good solderability. Note that FIG. 3 shows a flow of the above operation.

Next, a flux applying method according to the second embodiment of the present invention will be described with reference to FIG. This embodiment is characterized in that a nozzle driving device 50 is provided. And this nozzle drive device 51 is a spray nozzle 25,
26 is driven in the nozzle driving direction 51.

In this structure, the substrate 21 is the spray nozzle 2
When reaching the vicinity of 5, 26, the spray nozzles 25, 26 start reciprocating movement in the direction of 51 by the nozzle driving device 50, and at the same time, the flux 29 containing a small amount of solids and a small amount of activator.
To start coating. The flux controller (not shown) is preliminarily input with the data of the dimension in the carrying direction of the area A in which soldering can be performed with a flux having a small solid content and a small amount of activator as shown in FIG. 2, based on the information. After a predetermined time, a flux having a large amount of solids and a large amount of activator is applied to the region B shown in FIG. At this time, the spray from the spray nozzle 25 is stopped, but the spray can be continued depending on the spray conditions. In the second embodiment, the flux can be applied more uniformly than in the first embodiment, so that the soldering quality is also improved.

Next, a flux applying method according to a third embodiment of the present invention will be described with reference to FIGS.
In this example, the flux 8 containing a large amount of solids and a large amount of activator was used.
One spray nozzle 80 for spraying No. 5 and a plurality of spray nozzles 81 to 84 for spraying fluxes 86 to 89 having a small amount of solid content and a small amount of activator are provided. Reference numeral 90 in the figure denotes the substrate transfer direction. FIG. 8 shows a soldering surface of the substrate 21, which includes a capacitor lead 22a, a connector terminal lead portion 23a (narrow pitch), and an IC lead portion 24.
a, the chip component 31, and the contact test land 32 are exposed. A is a region in which soldering is possible with a flux having a small amount of solid content and activator, B is a region in which soldering failure occurs frequently when the amount of solid content and activator is not large, and D is the substrate transport direction.

In this operation, the substrate 21 is the spray nozzle 80.
When approaching the vicinity of 84 to 84, a flux 85 containing a large amount of solids and a large amount of activator from the spray nozzle 80 is applied to the region B.
And the fluxes 86 to 89 having a small solid content and a small amount of activator are applied to the area A from the nozzles 81 to 84. The substrate 21 on which the flux application has been completed is subjected to flow soldering by jet soldering.
Observing that the area A has a small amount of residue and poor soldering. Region B has a slightly large amount of residue but few soldering defects. This method can shorten the lead time of soldering as compared with the first embodiment, but it is necessary to pay attention to the warp of the board.

A flux applying apparatus according to a fourth embodiment of the present invention will be described below with reference to FIG. This apparatus includes a tank 60 for flux 60a having a small amount of solids and an activator, a main body 61 of a flux coating apparatus, an exhaust duct 6
2, transport rail 63, spray nozzle 64, substrate detection sensor 65, flux controller 66, atomization shape pressure control valve 67, flux discharge pressure control valve 68, and high pressure air supply source 69.
In addition, 70 is a spray-like flux.

The operation of the fourth embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 6, the soldering board 21 is carried by the carrying rail 63 of the flux applying device 62, and when the board reaches a predetermined position, the board detection sensor 65 detects the board and after a predetermined time elapses based on the information, The flux 60a having a small solid content and a small amount of activator is sprayed from the spray nozzle 64 and applied to the substrate 21. The flux controller 66 previously has good solderability as shown in FIG. 2 and can be soldered with flux having a small solid content and a small amount of activator. The dimension data in the conveyance direction of the bad region B has been input, and the atomization shape pressure control valve 6 is input after a predetermined time based on the information.
7. The flux application pressure control valve is operated to apply an amount 1.5 to 3 times as large as that in the region B to the region B. Flow soldering is performed on the substrate on which the flux application has been completed by jet soldering. When the substrate 21 is observed thereafter, the amount of residue in the area A is small and soldering defects are small. Region B has a slightly large amount of residue but few soldering defects. In this substrate 21, contact test lands 32, which cause a pin contact failure when a large amount of residue is generated, are arranged in the area A, and a narrow-pitch connector in which a bridge failure is less likely to occur is arranged in the area B. , Substrate 2
Even if No. 1 is not cleaned, the pin contact property and solderability are good.

Further, in the fourth embodiment, a plurality of flux tanks and nozzles are used in the same manner as in the above-mentioned embodiment, the same flux is filled, and one spray nozzle is provided in the area A and one is provided in the area B. It is also possible to carry out by applying from a plurality of nozzles.

The flux applying apparatus of this embodiment is
The flux applicator can be used alone, but can also be incorporated into a flow soldering device for use.

Next, Table 1 shows the results of soldering experiments in the conventional example and the first, second and third embodiments of the present invention and the fourth embodiment.

[0030]

[Table 1]

[0031]

As is apparent from the above description of the embodiments, according to the present invention, different fluxes are applied to parts having different solderability in the same board surface, so that the board is not cleaned. The soldering with good pin contact property and soldering property can be performed even if it is applied. Also, by changing the amount of flux applied to parts with different solderability on the same board surface, good solderability can be achieved for both pin contact and solderability even if the board is not cleaned. be able to.
Furthermore, collect parts with poor solderability in the peripheral area of the board,
By arranging the pin contact test lands around the parts with good solderability, it is possible to change the amount of flux applied partially to eliminate the need for cleaning the board and improve the solderability. Even if it occurs, it will be easy to manage and correct it.

[Brief description of drawings]

FIG. 1 is a perspective view of a flux applying apparatus according to a first embodiment of the present invention.

FIG. 2 is a plan view of a soldering board according to the first embodiment.

FIG. 3 is a flowchart of flux application in the first embodiment.

FIG. 4 is an overall configuration diagram of a flux coating device according to the first embodiment.

FIG. 5 is a perspective view of a flux applying device according to a second embodiment of the present invention.

FIG. 6 is an overall configuration diagram of a flux applicator according to an embodiment of the fourth invention of the present invention.

FIG. 7 is a perspective view of a flux coating device according to a third embodiment of the present invention.

FIG. 8 is a plan view of a soldering board according to the third embodiment.

FIG. 9 is a perspective view of a conventional flux coating device.

FIG. 10 is a perspective view of another conventional flux applying device.

[Explanation of symbols]

21 Electronic Circuit Substrate 22 Capacitor 23 Connector Terminal 24 IC 25 Spray Nozzle for Flux with Solid Content and Small Activator Amount 26 Spray Nozzle for Flux with Solid Content and Large Activator Amount 29 Spray Flux

Claims (7)

[Claims] 1. A flux applying method of applying different kinds of flux by a plurality of spray nozzles to components having different solderability in the same board surface in flow soldering of an electronic circuit board. 2. The flux coating method according to claim 1, wherein the coating amounts of different types of flux are changed. 3. The flux coating according to claim 1 or 2, wherein the electronic circuit board is provided with parts where bridging failure is likely to occur around the board, and pin contact test lands are provided around parts where failure is less likely to occur. Method. 4. A flux applicator having a plurality of spray nozzles, a plurality of flux tanks containing different kinds of flux, and a controller for controlling each spray. 5. The flux applicator according to claim 4, further comprising a drive device for reciprocating the spray nozzle. 6. The flux coating apparatus according to claim 4, further comprising a controller capable of changing a flux coating amount while coating one substrate. 7. The flux applicator according to claim 6, further comprising a drive device for reciprocating the spray nozzle.