JP3169401B2 - Device for preventing solder adhesion of holding claws - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing solder from sticking to a holding claw, and more particularly to a device for transferring an object such as a printed circuit board and performing automatic soldering. The present invention relates to a solder adhesion preventing device and a solder adhesion preventing method for preventing solder from adhering.

[0002]

2. Description of the Related Art In an automatic soldering apparatus, when a printed circuit board is soldered, a foaming fluxer has been used as an apparatus for applying a flux. A foaming fluxer is a method in which a porous foaming tube is immersed in a liquid flux, and compressed air is sent into the foaming tube to generate small bubbles from the foaming tube and the printed circuit board contacts the foamed flux. By doing so, a flux is applied to the surface of the printed circuit board. Since the foamed fluxer can apply a large amount of flux to the entire surface of the printed circuit board, it is excellent in improving solderability.

However, if a large amount of flux residue adheres to the printed circuit board after soldering, the flux residue absorbs moisture or attaches dust, thereby deteriorating insulation resistance. Therefore, in the case of a printed circuit board used in an electronic device that values reliability, such as a computer and a communication device, it is necessary to clean the flux residue after soldering. Solvents such as chlorofluorocarbon and trichlene having excellent detergency are effective for cleaning flux residues. However, CFCs are known as substances that destroy the ozone layer surrounding the earth. Tricline also
Penetrating underground pollutes drinking water and causes pollution.
Accordingly, the use of such substances has been regulated.

[0004] Therefore, when soldering to a printed circuit board, a spray fluxer is recommended so that the flux application amount can be minimized so that the flux residue does not need to be cleaned after soldering. In the spray fluxer, a liquid flux is made into a fine liquid by compressed air or ultrasonic waves, and is applied in a small amount only to a required portion of a printed circuit board.

[0005]

When the printed circuit board is soldered by an automatic soldering device provided with a spray fluxer, the solder adheres to the holding claws for holding the printed circuit board, and thereby the printed circuit board of the nail is attached. The holding portion for holding is closed, and the printed circuit board cannot be held reliably. Alternatively, an accident occurs in which the printed circuit board falls during the soldering process. In addition, the solder attached to the nail may drop on the way, causing inconvenience such as deterioration of the appearance.

The inventors of the present application have studied in detail the cause of the solder adhering to the holding claws in an automatic soldering apparatus provided with a spray fluxer. As a result, the holding claws holding the printed circuit board come into contact with the molten solder. In this case, it was found that the thin oxide film of the solder floating on the molten solder was caught on and attached to the holding claws.

Accordingly, the present inventors have proposed that when the printed circuit board comes into contact with the molten solder, if the oxide film does not exist on the molten solder, the holding claw will contact the oxide film even if it comes into contact with the molten solder. Paying attention to the fact that no longer adheres, the present invention has been completed.

That is, according to the present invention, in an automatic soldering apparatus having a spray fluxer, the holding claws come into contact with the oxide film of the molten solder and the holding claws scoop up the oxide film so that the solder adheres to the holding claws. It is an object of the present invention to provide a solder adhesion preventing device and a solder adhesion preventing method which prevent the occurrence of the solder adhesion.

[0009]

According to a first aspect of the present invention, there is provided an application apparatus for applying a solution of a substance having a function of reducing the surface tension of solder and a function of reducing the oxide of solder to a holding claw. The holding claw is provided at a position just before holding, and the solution is applied to the holding claw by the coating device, and the holding claw holds and conveys the object to be conveyed, and brings the object into contact with the molten solder. It is.

According to a second aspect of the present invention, in the first aspect, the substance having the effect of reducing the surface tension of the solder and the action of reducing the oxide of the solder includes organic acids such as rosin, stearic acid and adipic acid, and amines. A solution composed of one or two or more of amine halides such as chlorides and bromides and dissolved in a low-boiling solvent such as alcohol, acetone, and toluene or water in an amount of 1 to 10% by weight is the solution described above. The holding claw is applied by an application device.

According to a third aspect of the present invention, in the first aspect, the holding claw is conveyed by an endless conveyance means, and faces the return path of the holding claw conveyed by the conveyance means. The application device is provided, and the application device includes a brush and a solution supply unit that supplies the solution to the brush, so that the holding claw contacts the brush wet with the solution. Things.

According to a fourth aspect of the present invention, there is provided an automatic soldering apparatus for holding a transferred object in which a solution in which a substance having a surface tension reducing action of molten solder and an oxide reducing action of molten solder is dissolved at 1 to 10% by weight. After being applied to the holding claws to be carried out, the conveyed object is held by the holding claws and then brought into contact with the molten solder.

[0013]

According to the first aspect of the present invention, a solution of a substance having a function of lowering the surface tension of the solder and a function of reducing the oxide of the solder is applied to the holding claws by the coating device before holding the transferred object. . Thereafter, the holding claws hold and transport the object to be transported, and the object to be transported is brought into contact with the molten solder to perform automatic soldering.

According to a second aspect, the present invention comprises one or more of organic acids such as rosin, stearic acid and adipic acid, and amine halides such as amine chlorides and bromides, A solution prepared by dissolving 1 to 10% by weight in a low-boiling solvent such as alcohol, acetone, toluene or the like or water is applied to the holding claws by an application device, thereby lowering the surface tension of the solder, or Will be reduced.

According to the third aspect of the present invention, the coating device provided with the brush to which the solution is supplied by the solution supply device is disposed on the return path of the endless transport device, and the coating device is provided when the holding claw is transported by the transport device. And a solution of a substance having a function of lowering the surface tension of the solder and a function of reducing the oxide of the solder is applied.

According to the fourth aspect of the present invention, after a solution in which 1 to 10% by weight of a substance having a function of lowering the surface tension of the molten solder and a function of reducing the oxide of the molten solder is applied is applied to the holding claws, The holding claws come into contact with the molten solder while holding the transferred object.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 3 shows an automatic soldering apparatus having a solder adhesion preventing apparatus according to one embodiment of the present invention. This apparatus includes a spray fluxer 10, a preheater 11, a solder bath 12, and a cooling device 1 in order from the upstream side in the transport direction of the printed circuit board.
3 are provided. The transport chains 15 are arranged on both sides of the transport chains. The transport chain 15 is connected endlessly, and a portion indicated by an arrow 17 on the inside constitutes an outward route, and a portion indicated by an arrow 18 on the outside constitutes a return route.

Such an endless transport chain 1
As shown in FIG. 1 and FIG.
Is installed. The holding claw 20 has a holding portion 21 on the lower end side formed of a concave portion, and the holding portions 21 of the left and right holding claw 20 on the outward path 17 hold both sides of the printed circuit board.

An application device 24 as shown in FIGS. 1 and 2 is provided so as to come into contact with the holding claws 20 located on the return path 18 of the transport chain 15. The coating device 24 has a case 25. The case 25 is cut out on both sides in the moving direction of the chain 15 by notches 26 and 27, respectively, whereby the inside of the case 25 is
0 is allowed to pass. A brush 28 is provided in the case 25. The brush 28 has one end held by a holding body 29 as shown in FIG.
A solution supply pipe 30 is provided above the brush 28, and the application liquid is supplied to the brush 28 through a small hole 31 of the pipe 30. The brush 28 comes into contact with the holding portion 21 that holds the traveling holding claw 20 on both sides of the printed circuit board.

The solution supplied to the brush 28 by the solution supply pipe 30 contains 1 to 10% by weight of a substance having a function of lowering the surface tension of the molten solder and reducing the oxide of the solder.
It is a dissolved solution, and after applying such a solution to the printed board holding claws 20, particularly to the holding section 21,
The printed circuit board is held by the holding claws 20, and is brought into contact with the solder in the solder tank 12 of the apparatus shown in FIG.

If a solution is applied to the holding claws 20 in advance,
When the holding claws 20 come into contact with the molten solder, the surface tension of the molten solder is reduced, and the oxide of the solder is reduced. That is, the solute of the solution is melted by the heat of the molten solder and flows out to the surface of the molten solder. Then, this substance has a function of reducing oxides at high temperatures and a function of lowering the surface tension of the molten metal surface, so that it reduces a part of the oxide film floating on the surface of the molten solder and also reduces a part of the oxide film. By pushing to the side, the oxide film is removed around the holding claw 20.

In the solution used in the present embodiment, a substance having a function of lowering the surface tension of the solder and a function of reducing the oxide of the solder is added to the solvent in an amount of 1% by weight or more. Addition of less than 1% by weight reduces the effect of reducing or pushing the oxide film. Further, when this substance is added in excess of 10%, the reducing action and the pushing action are improved, but the amount of the substance increases, so that all the substances attached to the holding claws 20 melt on the molten solder. There is nothing left. If this is accumulated on the holding claws 20, the holding portions 21 for holding the printed circuit board will be blocked, and not only will the printed circuit board not be able to be completely held. Absorbs the water, thereby adhering to the first printed circuit board at the start of the next use and corroding the conductor of the printed circuit board.

The substance of the solution supplied to the brush 28 through the solution supply pipe 30 and applied to the holding claws 20 may be any substance as long as it has a function of lowering the surface tension of the molten solder and reducing the oxide of the solder. Anything can be adopted. The substance may be an organic substance such as rosin, stearic acid, adipic acid, or a halide of an amine such as HBr of triethanolamine and HCl of diethanolamine. One or a mixture of two or more of these substances is dissolved. As a solvent for dissolving such a substance, a solvent having a low boiling point such as isopropyl alcohol, acetone, and toluene is preferable. When dissolving a water-soluble substance, water may be used as a solvent.

As shown in FIG. 1 and FIG.
Is transported by the transport chain 15 of the automatic soldering device, and comes into contact with the solution supplied to the brush 28 when passing through the case 25 of the solution application device 24 on the return path, thereby printing the holding claw 20. The solution is applied to the holding unit 21 of the substrate 20. The holding claws 20 hold a printed circuit board (not shown) on the outward path 17 of the transport chain 15. This printed circuit board is spray fluxer 1.
At 0, flux application is performed, and preheating is performed by the preheater 11. Then, it is brought into contact with the solder in the solder bath 12 to perform soldering. Thereafter, the solder is fixed by cooling by the cooling device 13.

When the printed circuit board comes into contact with the molten solder in the solder bath 12, the holding claws 20 holding the printed circuit board also come into contact with the molten solder. At this time, the substance adhering to the holding claws 20 is melted by the heat of the molten solder and flows out to the surface of the molten solder. This spilled substance reduces the oxide film of the solder floating on the surface of the molten solder, or lowers the surface tension and pushes the solder to the edge, leaving no oxide film. The surface of the molten solder having no oxide film is held by the claw 2
Even if 0 passes, nothing is attached to the holding claws 20. The printed circuit board passing through the solder bath 12 is cooled by a cooling device 13.
After being cooled in, it is transferred to the conveyor of the next step. The holding claw 20 having separated from the printed circuit board enters the return path 18 and the solution is again applied by the solution applying device 24.

When soldering a printed circuit board with an automatic soldering apparatus equipped with a spray fluxer 10, a solution prepared by dissolving 5% by weight of rosin and 0.5% by weight of triethanolamine HBr in isopropyl alcohol is held. Nail 2
0, and soldering of 100 printed circuit boards revealed that no solder was attached to the holding claws 20.

On the other hand, when the coating device 24 was removed by the above-mentioned automatic soldering device and the printed circuit board was soldered without applying the above solution to the holding claws 20, the holding claws 20 were soldered by one printed circuit board. The solder adhered to the printed circuit board, and the solder accumulated on the holding portions 21 of the holding claws 20 due to the soldering of the ten printed circuit boards, making it impossible to reliably hold the printed circuit board.

[0028]

According to the first aspect of the invention, after the solution is applied to the holding claws by the application device, the holding claws hold and convey the object to be conveyed, and bring the object into contact with the molten solder. The solution of the substance having the effect of lowering the surface tension of the solder and the effect of reducing the oxide of the solder prevents the solder from adhering to the holding claws, thereby making it possible to reliably hold the transferred object by the holding claws.

The second invention comprises an organic acid such as rosin, stearic acid and adipic acid, and one or more kinds of amine halides such as chlorides and bromides of amines. A low-boiling solution such as acetone or toluene or a solution obtained by dissolving 1 to 10% by weight in water is applied to the holding nail by an application device. Accordingly, a solution of a substance having a function of lowering the surface tension of the solder and a function of reducing the oxide of the solder is applied to the holding claws.

According to the third aspect of the present invention, the holding claw comes into contact with the brush to which the solution has been supplied by the solution supply means on the return path of the transfer means, and the solder claw contacts the holding claw before holding the object to be transferred. It becomes possible to apply a solution of a substance having a surface tension lowering action and a solder oxide reducing action.

According to the fourth aspect of the present invention, a solution in which 1 to 10% by weight of a substance having a function of lowering the surface tension of molten solder and a function of reducing oxide of molten solder is dissolved is transferred to an automatic soldering apparatus. After application to the holding claws to be held, the object to be conveyed is held by the holding claws and then brought into contact with the molten solder. Therefore, by applying such a solution, the molten solder is prevented from adhering to the holding claws, and it is possible to reliably hold the transferred object by the holding claws.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a device for preventing solder adhesion of a holding claw.

FIG. 2 is a longitudinal sectional view of the solder adhesion preventing device.

FIG. 3 is a plan view of the automatic soldering apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Spray fluxer 11 Preheater 12 Solder tank 13 Cooling device 15 Transport chain 17 Outgoing path 18 Return path 20 Holding claw 21 Depression (holding part) 24 Coating device 25 Case 26, 27 Notch 28 Brush 29 Holding body 30 Solution supply pipe 31 Small Hole

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichi Tomizuka 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Zen Mitsuo 23-23 Senju-Hashido-cho, Adachi-ku, Tokyo Genju-kin Inside the Industrial Co., Ltd. (72) Inventor Hidetoshi Nakamura 23, Senjuhashido-cho, Adachi-ku, Tokyo Inside the Senju Metal Industry Co., Ltd. (56) References JP-A-2-180666 (JP, A) Jpn. JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05K 3/34 B23K 1/08

Claims (4)

(57) [Claims] An application device for applying a solution of a substance having a solder surface tension reducing action and a solder oxide reducing action to a holding claw at a position before the holding claw holds an object to be conveyed; Wherein after the solution is applied to the holding claws by a device, the holding claws hold and convey the object to be conveyed, and the object to be conveyed is brought into contact with the molten solder. apparatus. 2. The substance having the effect of lowering the surface tension of the solder and the action of reducing the oxide of the solder include organic acids such as rosin, stearic acid and adipic acid, and amine halides such as amine chlorides and bromides. So that a solution composed of one or two or more substances and dissolved in water at a low boiling point such as alcohol, acetone, and toluene, or 1 to 10% by weight is applied to the holding nail by the coating device. 2. The device as claimed in claim 1, wherein the solder is prevented from sticking to the holding claws. 3. The holding claw is conveyed by endless conveyance means, and the coating device is arranged so as to face the holding claw conveyed by the conveyance means during a return path. 2. The holding device according to claim 1, further comprising a brush, and a solution supply unit configured to supply the solution to the brush, wherein the holding claw contacts the brush moistened by the solution. 3. A device for preventing solder adhesion to nails. 4. A solution in which a substance having a surface tension lowering action of molten solder and an oxide reducing action of molten solder is dissolved in an amount of 1 to 10% by weight is applied to a holding claw of an automatic soldering apparatus for holding a transferred object. And holding the transferred object by the holding claw and then bringing the object into contact with the molten solder.