JP2664659B2 - Flux coating method and fluxer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flux applying method for applying a flux to an article to be soldered, and a fluxer directly used in carrying out the method.

[0002]

2. Description of the Related Art Normally, when soldering is performed, a flux is applied in advance to a portion where soldering is to be performed on a product to be soldered. The flux cleans the soldered portion, reduces the oxide of the soldered portion by a reducing action, and improves the wettability by lowering the surface tension of the solder.

In recent years, as electronic components have become more highly integrated and miniaturized, highly integrated components such as ICs and chip components and components having leads such as capacitors have been densely mounted on a printed circuit board. It is mixed.

[0004] In order to solder a printed circuit board on which electronic components are mixed at a high density, soldering may be partially applied to a plurality of portions of the printed circuit board. In this case, in the step of applying the flux performed before the soldering step, it is necessary to partially apply the flux only to a portion of the printed circuit board where soldering is to be performed. Otherwise, the printed circuit board may be defective due to the flux applied to unnecessary portions.

Conventionally, for example, in a foaming type fluxer incorporated in a jet type soldering device, a flux is partially applied to a plurality of portions of a printed circuit board by the following method. That is, a plurality of foaming tubes are provided inside the flux tank, bubbles continuously generated therefrom are guided into the inside of the flux nozzle provided above the foaming tubes, and the flux is blown up from the upper opening of the flux nozzle. By applying the blown-up flux to predetermined locations on the back surface of the printed circuit board previously arranged above the flux tank, the flux is partially applied only to a plurality of locations on the printed circuit board.

[0006]

However, the above-mentioned conventional partial flux coating method has the following problems. If flux is to be applied to only a limited area of the printed circuit board, a small opening flux nozzle must be used. However, when a flux nozzle having a small opening is used, bubbles are easily broken inside, and the blowing of the flux is not stable. For this reason, as shown in FIG. 4, even when the flux 1 is to be applied only to a limited portion S on the back surface of the printed circuit board P, the amount of flux blow-up must be set to a relatively large amount.
In this case, there is a problem that the flux 1 flows into or oozes out not only at a necessary portion but also at another portion adjacent to the necessary portion, thereby causing a problem of coating. In addition, 2 in FIG.
Indicates an electronic component or an electrical component.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a method of applying a flux capable of applying a flux to only a necessary portion of a surface of a soldered article and a method for directly applying the method. It is intended to provide a fluxer to be used.

[0008]

According to the first aspect of the present invention, a flexible resin material is provided at the tip of a flux nozzle arranged upward so as to form a ring along the nozzle tip and the nozzle tip. Is provided so as to protrude upward, and at least one of the flux nozzle and the soldered article disposed above and opposed to the flux nozzle is moved in a direction approaching each other to bring the resin material into close contact with the surface of the soldered article. Thereafter, the flux is blown up from the flux nozzle to apply the flux to the back surface of the soldered article. According to the second aspect of the present invention, a flux tank for storing a flux, a flux nozzle disposed inside the flux tank with its tip directed upward, and a flux blowing means for blowing up the flux stored in the flux tank from the flux nozzle In a fluxer comprising: at the tip of the flux nozzle,
A flexible resin material is provided in a ring shape along the nozzle tip and protrudes upward from the nozzle tip. The invention according to claim 3 is characterized in that the resin material is supported by being sandwiched between a side wall of the flux nozzle and a pressing plate arranged in parallel with the side wall.

According to the present invention, the resin material provided at the tip of the flux nozzle hermetically surrounds a portion of the surface of the article to be soldered to which the flux is to be applied, and the flux flows outward from the portion. And prevent bleeding.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a fluxer according to the present invention. The fluxer 10 is incorporated in a jet-type partial soldering device that partially solders a plurality of portions of a printed board P to be soldered, and specifically, transports the printed board P. It is directly below the conveyor 25 which is a line, and is incorporated in the preceding stage of the soldering process.

The fluxer 10 includes a support frame 11 and
A lower rail 14 is supported by the support frame 11 via left and right guides 12, 12 so as to be able to move up and down, and is operated to move up and down by a central cylinder 13. A rail upper base 16 movably supported in the direction, and a flux tank 18 supported on the rail upper base 16 via bolts 17a and nuts 17b serving also as height adjustment and horizontal adjustment functions. I have. The slider mechanism 15 is not usually used, and is mainly used for maintenance.

The size of the flux tank 18 is set so as to cover the entire back surface of the printed circuit board P, and a plurality of foam tubes 20 are arranged near the inner bottom. The foaming tube 20 generates air bubbles by introducing air from the air introducing tube 21, and generates a flux stored in the flux tank 18 by the generated air bubbles.
It functions to blow up from the opening 22a of the flux nozzle 22 disposed above the foam tube 20.

The flux nozzle 22 is connected to the foam tube 20.
It comprises a lower nozzle portion 23 having a communication hole (not shown) so as to cover the outer periphery and allow the flux 1 to enter therein, and a narrower nozzle upper portion 24 rising upward from the lower nozzle portion 23. And the opening 2 of the nozzle upper part 24
The flux nozzle is pre-positioned and fixed to the flux tank 18 so that 2a faces the position where soldering of the printed circuit board P, which is positioned and stopped on the conveyor 25, is performed.

The nozzle upper part 24 has one nozzle lower part 23.
Is not always provided only one,
As in the flux nozzle 22 on the right side in FIG.
Two nozzle upper portions 24 may be provided for one nozzle lower portion 23, or three or more nozzle upper portions 24 may be provided.

At the tip of the nozzle upper portion 24, a resin material 28 having flexibility, solvent resistance and chemical resistance is provided.
So that it forms a ring along the tip of
4 so as to protrude upward. Specifically, the resin material 28 is arranged in a ring shape having a diameter slightly larger than the tip of the nozzle upper portion 24 and arranged in parallel with the side wall portion of the nozzle upper portion 24 and the outside thereof, or is formed as a separate body into a square shape. The resin material 28 is sandwiched between the four holding plates 29 to be assembled, and in this state, bolts 30 are screwed from the outside through the holding plate 29 and the resin material 28 and screwed to the nozzle upper part 24, so that the resin material 28 It is mounted outside the nozzle upper part 24. The resin material 28 has a nozzle upper 2
For example, a plate-shaped member having a length enough to surround the front end of the member 4 or a member formed in a ring shape in advance is used. Further, as a material, for example, a silicon-based sponge is used. .

Next, a method of applying a flux using the fluxer 10 having the above configuration will be described. The printed circuit board P is transported by the transport conveyor 25, but is stopped by a stopper (not shown) when it reaches a predetermined position. Subsequently, the cylinder 13 is driven to raise the flux tank 18 via the lower rail 14 or the like, and the flux nozzle 2
The resin material 28 attached to the tip of the second substrate 2 is brought into close contact with the back surface of the stopped printed circuit board P (see FIG. 3). Then
Air is introduced from the air introduction pipe 21, and bubbles are generated from the foaming pipe 20. The bubbles are stored in the flux tank 18 through the opening 22 a of the flux nozzle 22.
Blow up from At this time, the blown-up flux 1 contacts the back surface of the printed circuit board P, and the flux 1
Is applied. Since it takes some time until air is introduced from the air introduction pipe 21 and the flux 1 rises, the flux 1 is blown up immediately after the resin material 28 is brought into close contact with the back surface of the printed circuit board P in consideration of this time. Before the resin material 28 is brought into close contact with the back surface of the printed circuit board P, air may be supplied from the air introduction tube 21 to generate bubbles from the foam tube 20 in advance.

Here, as described above, the resin material 28 at the tip of the flux nozzle 22 is brought into close contact with the back surface of the printed circuit board P, and only the portion of the back surface of the printed circuit board P to which the flux 1 is to be applied by the resin material 28. , It flows out of the area where flux 1 is applied,
No oozing will occur. As a result, it is possible to avoid a situation in which the flux 1 is applied to unnecessary portions and causes a substrate failure.

The method of applying the flux 1 of the present invention is not limited to the above-described embodiment, and specific constituent elements can be appropriately changed upon implementation.

For example, in the above-described embodiment, a silicon sponge is used as the resin material 28 provided at the tip of the flux nozzle 22, but the present invention is not limited to this, and another resin material may be used. However, when another resin material is used, it has such flexibility that it can be in close contact with the back surface of the printed circuit board P when it is raised, and the flux 1
It is necessary to use a material having chemical resistance that does not soften or harden and is not dissolved. Further, in the above-described embodiment, the resin material 28 is attached to the outside of the flux nozzle 22, but is not limited to this, and may be provided inside the flux nozzle 22. Furthermore, in the above-described embodiment, the flux nozzle 22 side is moved up and down to move the printed circuit board P and the flux nozzle 22 toward and away from each other. However, the present invention is not limited to this. You may make it raise and lower 25 every.

[0020]

According to the first aspect of the present invention, the portion of the printed circuit board on which the flux is to be applied is surrounded by the flexible resin material. It does not flow out or bleed out, and it is possible to avoid a situation in which the flux is applied to unnecessary portions to cause a substrate defect. According to the second aspect of the present invention, the method of the first aspect can be easily implemented. According to the third aspect of the present invention, since the resin material is sandwiched and supported between the side wall of the flux nozzle and the pressing plate, the mounting strength to the resin material can be increased, and therefore, the resin material can be used. There is no danger that the flux nozzle will shift downward when it is brought into close contact with the soldered product, and the contact portion between the resin material and the flux nozzle can be kept airtight, so that the flux can be prevented from leaking from this contact portion.

[Brief description of the drawings]

FIG. 1 is a sectional view of a fluxer showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a portion X in FIG.

FIG. 3 is a cross-sectional view illustrating an operation of the embodiment.

FIG. 4 is a cross-sectional view illustrating a problem of a conventional method of applying a flux.

[Explanation of symbols]

 P Printed Circuit Board 1 Flux 2 Parts 10 Fluxer 13 Cylinder 18 Flux Tank 20 Foaming Tube (Flux Spraying Means) 22 Flux Nozzle 22a Opening 23 Nozzle Lower 24 Nozzle Upper 28 Resin Material

Claims (3)

(57) [Claims] 1. A resin material having flexibility is provided at the tip of a flux nozzle arranged upward so as to form a ring along the tip of the nozzle and protrude upward from the tip of the nozzle. At least one of the parts to be soldered facing upward is moved in a direction approaching each other to bring the resin material into close contact with the surface of the part to be soldered, and then the flux is blown up from a flux nozzle to cover the part. A method for applying a flux, comprising applying a flux to the back surface of a soldered product. 2. A flux tank for storing a flux,
In a fluxer provided with a flux nozzle provided with a tip directed upward inside a flux tank, and a flux blowing means for blowing up the flux stored in the flux tank from the flux nozzle, the tip of the flux nozzle has flexibility. A fluxer, comprising: a resin material having a ring shape along the nozzle tip and protruding above the nozzle tip. 3. The fluxer according to claim 2, wherein the resin material is sandwiched and supported between a side wall of the flux nozzle and a pressing plate arranged in parallel with the side wall.