JPH0623538A - Flux coating equipment - Google Patents

Abstract

PURPOSE:To provide a flux coating equipment where the foam diameter of the foam flux is kept to the small foam diameter when being foamed, the foam flux is the uniform and fine foam condition is waved, and reaches fine parts on the surface to be soldered in the foam condition, and the flux of excellent mixture is obtained. CONSTITUTION:A nozzle body 5 consisting of a circumferential wall 4 is arranged to a flux tank, a foaming tube 6 to foam the flux within this nozzle body 5 is arranged within the nozzle body 5, a foam waving port 7 to wave the foaming flux upward is formed to the upper part of this nozzle body 5, the nozzle body 5 is arranged to the position where the surface 1A to be soldered of a circuit substrate 1 may approach to and pass by the upper side of this foaming waving port 7, and an inclined circumferential wall 4A which is inclined toward the inside of the nozzle body 5 facing upward and is gradually thinned toward the top is mounted on the circumferential wall 4 of the nozzle body 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flux coating device in a circuit board automatic soldering process.

[0002]

2. Description of the Related Art There is an automatic soldering apparatus for transporting a circuit board and soldering the soldered surface of the circuit board, for example, through a solder bath in which molten solder water is jetted.

This automatic soldering apparatus is provided with a flux applying apparatus for applying flux to the soldering surface of a circuit board to be transported as a pretreatment for performing the soldering processing.

In general, by applying flux to the soldered surface, the oxide film formed on the soldered portion is removed, and electrical contact failure between the solder after soldering and the soldered portion is prevented.

It is prevented that an oxide film is formed again before being transported to the solder bath.

The inclusion of pine or the like (solid content) improves the adhesion with solder.

It is for giving the following effects.

Conventionally, this flux coating apparatus is arranged in parallel below the circuit board that is conveyed with the soldering surface facing down toward the solder bath, on the front side in the transport direction of the solder bath via a substrate preheating device. In this state, a nozzle body for jetting (overflowing) the flux is provided at a position where the soldered surface of the circuit board to be conveyed closely passes above.

Specifically, a flux tank containing the flux is provided with a nozzle body protruding above the height of the flux liquid surface, a foam tube is installed in the nozzle body, and the upper end of the nozzle body is adjusted to the soldered surface width. It is equipped with a foaming jet port with a wide width.

Accordingly, the flux is foamed by the foam tube and jetted from the foam jet port at the upper end, and the circuit board is conveyed so as to pass above the foam jet port in an approaching state, and is attached to the soldered surface on the lower surface of the circuit board. The foaming flux is contacted and applied.

Such a foaming jet method has excellent work efficiency and is suitable for automation as compared with a method of immersing a circuit board in a flux, and the foaming method causes bubbles to penetrate into the details and burst into the bubbles. Due to the phenomenon, the flux is applied in detail, and the soldered surface is evenly splashed, which is an extremely excellent application method. As described above, the foaming jet method is a very excellent method, but in order to make full use of this characteristic, it is desirable to jet a foaming flux that becomes uniform and fine bubbles.

[0012]

However, in the conventional flux device, the bubbles (flux) having a predetermined size generated in the foam tube rise in the flux toward the foam jet port at the upper end. Since the flux liquid pressure (internal pressure) is lower in the upper portion than in the lower portion, there is a problem that the bubbles grow and become large bubbles as they rise.

In order to avoid this, it is conceivable to raise the bubbling position, that is, the position where the bubbling liquid in the bubbling tube is immersed in the flux. Does not mean

Therefore, in the conventional flux coating device,
The requirement for a foaming flux in the form of a fine foam that penetrates into the above-mentioned details as a foam has not yet been sufficiently satisfied.

On the other hand, due to recent demands for environmental improvement, the use of freon, trichloroethane, etc., which have been used as the solid content of the flux, is suppressed, so that a low residue flux with a low solid content of the flux and a low viscosity is used. The Rukoto.

Therefore, the growth of bubbles accompanied by the rise of bubbles is more remarkable than that of the flux having a high solid content, and the above problems become important problems to be solved.

The present invention solves such a problem and maintains the bubble diameter of the foaming flux at a small bubble diameter at the time of foaming to make it uniform and finely spread to the details of the soldered surface in the foam state. An object of the present invention is to provide a flux coating device that jets a foaming flux with good splashing.

[0018]

The gist of the present invention will be described with reference to the accompanying drawings.

This is a flux applying apparatus in an automatic soldering process of a circuit board for applying the flux 2 to the soldering surface 1A of the circuit board 1 as a pretreatment for soldering the circuit board 1 from the peripheral wall 4 to the flux tank 3. The nozzle body 5 is disposed, the foam tube 6 for foaming the flux 2 in the nozzle body 5 is disposed in the nozzle body 5, and the flux 2 foaming above the nozzle body 5 is jetted upward. The foam jet port 7 is formed, and the nozzle body 5 is disposed at a position where the soldered surface 1A of the circuit board 1 can pass above the foam jet port 7 in the vicinity thereof, and the nozzle body 5 is provided above the peripheral wall 4 of the nozzle body 5. The flux coating apparatus is characterized in that an upwardly tapered peripheral wall 4A that is inclined toward the inside of the nozzle body 5 is provided.

The flux coating apparatus according to claim 1, wherein the inclination degree of the upper tapered peripheral wall 4A is adjustable.

The circuit board 1 is provided with a capillary force generating member 8 for drawing in the foaming flux 2 by a capillary action on the side of the foaming jet port 7 in the carrying direction of the circuit board 1.
2. The foamed flux 2 applied to the soldered surface 1A by transporting the solder is prevented from being excessively attracted to the soldered surface 1A and applied excessively. The present invention relates to a flux coating device.

[0022]

Since the peripheral wall 4 of the nozzle body 5 is provided with the upwardly slanted peripheral wall 4A which is inclined upward toward the inside of the nozzle body 5, the liquid pressure (internal pressure) in the flux 2 in the nozzle body 5 is
The state does not become lower as it goes upward, and the bubbles come closer to each other as they go up along the upwardly tapered peripheral wall 4A, so that the internal pressure is increased. Therefore, due to the inclination of the upwardly inclined peripheral wall 4A, the setting can be changed so that the internal pressure does not become lower than that at the lower side, for example, at the upper side.

Therefore, even if the uniform foam generated from the foamed tube 6 submerged in the flux 2 rises, the growth of the foam is suppressed by the pressurization phenomenon due to the upwardly slanted peripheral wall 4A, and the foam becomes uniform near the time of occurrence. Then, the foam is jetted from the foam jet port 7 in the state of fine bubbles. Also, the upper and lower inclined peripheral wall 4A
If the inclination is freely adjustable, the degree of pressurization of the flux internal pressure at the upper side is adjusted, so that the degree of suppression of bubble growth is adjusted.

As a result, it is possible to adjust the size of the foam of the foaming flux 2 which is foamed and jetted.

Further, if the capillary force generating member 8 is arranged in parallel on the side of the foam jet port 7 in the carrying direction of the circuit board 1, when the foam flux 2 jetted to the soldered surface 1A of the circuit board 1 is applied by contact, Due to the surface tension of the soldered surface 1A, the surface tension of the foaming flux 2 and the interfacial tension between them, the foaming flux 2 tends to be attracted to the soldered surface 1A passing and moving more than necessary. Capillary force (pull-in force) downward due to capillary action
Therefore, in addition to the gravity of the flux 2 itself, the foaming flux 2 is added by the capillary force.
Is separated downward from the soldered surface 1A, and the foaming flux 2 becomes uneven and is prevented from being applied excessively.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the schematic construction of this embodiment will be described with reference to FIGS.

A hood-shaped nozzle body 5 projecting upward above the level of the flux liquid surface is arranged in a flux tank 3 containing the flux 2 in the width direction of the circuit board 1 which conveys and passes above the nozzle body. A foaming pipe 6 for foaming and jetting the flux 2 is installed in the nozzle 5, and a foaming jet port 7 is formed in the upper end width direction of the nozzle body 5 at a position close to the soldered surface 1A on the lower surface side of the circuit board 1 which is conveyed and passed. is doing.

In this embodiment, the hood-shaped nozzle body 5 is constructed as follows.

The bottom of the nozzle body 5 is formed in a substantially rectangular shape, and the foam tube 6 is installed on the bottom side of the rectangular peripheral wall 4.
On the upper side of the peripheral wall 4, there is formed a foam jet port 7 protruding in a long mouth shape.

FIGS. 1 to 4 show a first embodiment of a nozzle body 5 in which the degree of inclination can be finely adjusted and an example of an embodiment using the nozzle body 5. In this embodiment, the square peripheral wall 4 has a pair of upwardly tapered peripheral walls 4A formed by forming an upper side of an opposing peripheral wall, which is provided in the front-rear direction of the circuit board 1 to be described later, in a C-shaped cross section. And the bottom side thereof is formed as a vertical wall 4B. Further, in this embodiment, the side wall 4C arranged in the direction orthogonal to the upwardly slanted peripheral wall 4A is formed so as to rise vertically, and the entire peripheral wall 4 is formed.
Is formed in a substantially rectangular shape.

The foaming jet port 7 is formed by vertically rising the upper ends of the opposing peripheral walls 4A and 4C.

Further, in this embodiment, the upper tapered slanted peripheral wall 4A is used.
Is configured such that the upper end side thereof can be freely opened and closed with reference to the lower end portion of the vertical wall 4B that is provided continuously with the vertical wall 4B.
The inclination of A is adjustable. Also, the foam tube 6
The liquid immersion position is also movable up and down. Therefore, the fineness of the inclination of the upper slanted peripheral wall 4A and the position of the foaming tube 6 is finely adjusted so that the foaming jet is stably generated, and the foaming state at the time of foaming is maintained as much as possible to make the foam uniform and the smallest possible foam. The foaming flux 2 in a state is configured to be jetted.

FIGS. 5 to 8 show a second embodiment of the nozzle body 5. In this embodiment, a pair of opposing peripheral walls of the circuit board 1 in the front-rear direction of conveyance are formed in a cross section in the same manner as described above. An upper tapered peripheral wall 4A is formed, and the opposite side walls 4C are also formed into a pair of upward tapered peripheral walls with a V-shaped cross section. Actually, a sufficient pressurizing effect is exerted by the pair of upwardly inclined peripheral walls 4A facing each other in the front-rear direction of conveyance with a narrow facing interval.

It is desirable that the upward inclination of the upwardly inclined peripheral wall 4A be designed in consideration of the degree of pressurization (the degree of suppression of bubble growth) so that fine bubbles close to the time of foaming stably foam the jet. It has also been confirmed that if this gradient is increased too much, the bubble rebound phenomenon is strong and stable foaming cannot be obtained.

Further, in the embodiment shown in FIGS. 3 to 8, the capillary force generating members 8 are arranged in parallel so as to be close to the foaming jet port 7 on the conveying direction side. An example in which the capillary force generating member 8 is provided will be described. In this embodiment, the foam jet nozzle 7 is used.
Attached to both ends of the circuit board 1 toward the transfer direction of the circuit board 1
Projecting in a facing state, a mounting shaft 15 is laid between the mounting portions 14 and 14 in parallel with the foam jet port 7, and the mounting shaft 15 has a length of several mm.
A large number of gap forming plates 9 are provided with a certain gap 10 therebetween.

The capillary force generating member 8 shown in FIGS. 3 and 4 has a mounting portion 14 attached to a part of the upwardly tapered peripheral wall 4A and moves together with the adjustment movement of the upwardly tapered peripheral wall 4A. Is configured as follows.

Therefore, the gaps 10 are evenly arranged in parallel in the foaming jet port 7, and since the gaps 10 penetrate from the upper side to the lower side, the foaming flux 2 jetting upward is generated. A capillary force that pulls downward into the gap 10 is always generated uniformly in the width direction.
Since the pulling force is generated by the action of the capillarity, a constant pulling force can be always generated without requiring a drive source or the like.

As described above, in this embodiment, since the foaming flux 2 is formed in a uniform and fine bubble state, a flux applying apparatus having a good wettability without uneven coating is obtained, and the capillary force generating member 8 serves to form the foaming flux 2. Good cutting performance prevents various problems caused by uneven coating.

The width of the gap 10 is designed so that an appropriate capillary force is generated, and the foaming flux 2 does not stay in the gap 10 and the capillary force is always maintained.

Further, the method of forming the gap 10 in the capillary force generating member 8 and the shape thereof are not limited to those in this embodiment, but may be directed downward (obliquely downward) with respect to the upper soldered surface 1A. It is sufficient that a capillary force is generated, and the gap 10 may be provided in parallel with the foam jet nozzle 7 in one line.
A plurality of gaps 10 may be provided in parallel with the foam jet nozzle 7. Further, the gap forming plate 9 may be further rotated in the same manner as in the present embodiment so that the force of pulling by this rotation is added to the capillary force. It may be generated to increase the pulling force.

Further, the structure of the flux coating apparatus to which the present invention is applied can be designed as appropriate, and the method of forming the upper tapered peripheral wall 4A, the means for adjusting the inclination of the upper tapered peripheral wall 4A, etc. are also suitable. It can be designed, and the opening width of the foaming jet port 7 may be configured to be adjustable according to the width of the circuit board 1 so that the stable foaming flux 2 is jetted.

In the figure, reference numeral 11 is a carrying claw for supporting and carrying the circuit board 1, and 12 are projectingly provided at both ends of the foam jet port 7, and the circuit board 1 is provided.
The guide protrusion edge portion that guides the jet flow so that the flux 2 does not go around to the side edge portion of the guide, and the upper edge of the guide protrusion edge portion 12 is inclined upward in the conveying direction, and the height of this top edge is 13. Is a conveyance claw guide edge designed so that the height of the circuit board 1 is appropriate.

[0043]

EFFECTS OF THE INVENTION Since the present invention is configured as described above, it is possible to suppress the growth due to the rise of bubbles, and to make it possible to jet a foaming flux of fine bubbles that is uniform and close to the time of foaming. An excellent flux applicator with no unevenness and good wetting.

Further, if the inclination of the upwardly slanted peripheral wall is adjustable, the bubble size of the foaming flux jetted in foaming can be adjusted, resulting in an extremely excellent flux coating device.

If a capillary force generating member is provided in parallel with the foam jet port on the side of the circuit board in the conveying direction, the foam flux is drawn downward by the capillary force generated by the capillary action, and the foam flux is unnecessarily increased. The flux coating apparatus is attracted to the soldered surface and uniformly coated without being excessively coated. The soldering process in the next step is good, and an extremely excellent flux coating apparatus capable of performing an appropriate soldering process.

[Brief description of drawings]

FIG. 1 is a perspective view of a nozzle body according to a first embodiment.

FIG. 2 is a side sectional view showing the adjustment of the degree of inclination of the upwardly inclined peripheral wall of the nozzle body of the first embodiment.

FIG. 3 is a perspective view of a nozzle body in an embodiment example in which a capillary force generating member of the first embodiment is provided.

FIG. 4 is a side sectional view showing the adjustment of the inclination of the upwardly inclined peripheral wall of the nozzle body and the vertical position adjustment of the foam tube in the embodiment example in which the capillary force generating member of the first embodiment is provided.

FIG. 5 is a schematic perspective view of a second embodiment.

FIG. 6 is a schematic configuration front view of the second embodiment in use.

FIG. 7 is a side view of the second embodiment in a use state immediately before the transfer of the circuit board.

FIG. 8 is a side view of the second embodiment in a use state when passing through a circuit board.

[Explanation of symbols]

 1 Circuit Board 1A Soldered Surface 2 Flux (Foaming Flux) 3 Flux Tank 4 Circumferential Wall 4A Upslope-Slanted Perimeter Wall 5 Nozzle Body 6 Foaming Tube 7 Foaming Jet Port 8 Capillary Force Generating Member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Arakawa 2-32 Higashi Zao, Nagaoka City, Niigata Prefecture Nippon Seiki Co., Ltd.

Claims (3)

[Claims] 1. A flux applicator in an automatic soldering process of a circuit board for applying flux to a soldered surface of the circuit board as a pretreatment for soldering the circuit board, wherein a nozzle body having a peripheral wall is provided in a flux tank. A foam pipe for foaming the flux in the nozzle body is arranged in the nozzle body, and a foam jet port for jetting the foam flux upward is formed on the upper part of the nozzle body, and the soldered surface of the circuit board is formed. The nozzle body is arranged at a position where it can pass above the foaming jet port in the vicinity thereof, and the peripheral wall of the nozzle body is provided with an upwardly tapered peripheral wall that inclines upward toward the inside of the nozzle body. Flux coating device. 2. The flux applicator according to claim 1, wherein the degree of inclination of the upwardly slanted peripheral wall is adjustable. 3. A capillary force generating member that draws in foaming flux by a capillary action is arranged in parallel on the side of the foaming jet port of the circuit board in the carrying direction, and is applied to the soldered surface by carrying the circuit board. Foaming flux
The flux coating apparatus according to claim 1, wherein the flux coating apparatus is configured to prevent the soldered surface from being unnecessarily attracted and excessively coated.