JPH07185791A - Soldering method and its device - Google Patents

Abstract

PURPOSE:To obtain a soldering method and device for printed circuit board which increase the thickness and velocity of laminar flow of molten solder and enhance the stability of surface shapes. CONSTITUTION:The flow of the molten solder 24 ejected out of a blow port 26 of a jet tank 25 is guided in an approximately horizontal direction by a flow guiding body 27 to form the laminar flow 24a. The flow guiding body 27 is composed of flow guiding plates 27A, 27B, 27C. A first flow guiding part 28 is formed at the flow guiding plate 27A, a descending part 29 of the molten solder 24 is formed at the boundary between the flow guiding plates 27A and 27B, a second flow guiding part 30 is formed at the flow guiding plate 27B and a rising part 31 where the molten solder 24 flows downward after rising is formed at the flow guiding plate 27C. The laminar flow 24a which is high in flow velocity and large in thickness is formed in the rising part 31 by the molten solder 24 increased in the flow velocity by the descending part 29. The wiring circuit board 22 is brought into contact with the laminar flow and is thus subjected to soldering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of transporting a wiring board in a direction opposite to a direction in which a laminar flow solder flows, and contacting the laminar flow solder with the wiring board to solder the wiring board. It relates to the device.

[0002]

2. Description of the Related Art A conventional apparatus for contacting a laminar flow solder with a wiring board for soldering will be described. In the following, the following seven publications will be used for explaining the conventional art.

Technique of Japanese Patent Laid-Open No. 55-16725 (referred to as known example 1) Technique of Japanese Patent Publication No. 5-55228 (referred to as known example 2) Technique of Japanese Patent Publication No. 4-42058 (referred to as known example 3) Technology of Japanese Patent Publication No. 58-56048 (referred to as known example 4) Technology of Japanese Patent Laid-Open No. 63-80961 (known as known example 5) Technology of Japanese Patent Publication No. 36-8713 (known as known example 6) Technology of Japanese Laid-Open Patent Publication (referred to as Known Example 7) For example, in the technology disclosed in Known Example 1, a laminar flow of molten solder having high surface flatness can be obtained, and the flow velocity can be increased. For this reason, the solder sufficiently flows into the fine and minute parts, and it becomes difficult for soldering spots such as unsoldered spots and insufficient solder amount to occur, and the spacing between the solders is good, and bridging and flicker phenomena are less likely to occur. There are advantages.

In addition, in the techniques of the known examples 2 and 3, the original advantages described above are lost because the molten solder rises and the surface flow velocity thereof remarkably decreases at the portion where the laminar flow of the molten solder comes into contact with the wiring board. This is a technology that reduces this.

That is, this is a technique in which a part of the laminar flow of the molten solder overflows from the side wall plate to reduce the rising phenomenon of the molten solder and the decrease in the surface flow velocity. Further, the direction, angle, and height of the opening control plate that forms the blowout port of the molten solder, the flat plate-shaped portion of the channel-shaped flow passage, and the side wall plate,
It is a technique for adjusting the thickness of the molten solder to obtain a desired laminar flow thickness and flow velocity.

Further, the technique of the known example 4 is a technique for increasing the thickness (height) of the jet solder wave while preventing the surface shape of the jet solder wave from being disturbed, and it projects to the soldering surface of the wiring board. This is a technology that relaxes restrictions on the length of terminals and lead wires of mounted electronic components.

In other words, this is a technique in which "a jet part for raising a solder wave and a jet part for generating a partial flow are separately provided so that a high-wave partial flow shape can be formed as a whole". Next, the technique of the known example 5 will be described with reference to FIGS.

FIG. 9 (a) is a side sectional view, in which a solder bath 1 is provided with a molten solder introduction passage 2 and a nozzle 3 is provided in communication therewith, from which molten solder is introduced. It is jetted by a pump 4 composed of rotary blades. A curved portion 3a is formed at the upper end of the nozzle 3. The wave former 5 is formed by forming the wave former lower member 5a at the lower end of the curved portion 3a, the wave former upper member 5b at the upper portion, and the side wall plate 5c. A bypass passage 6 is provided on the rear side of the nozzle 3, and an opening 6a is formed at the tip. Also, P
Is a printed board.

Further, FIG. 9 (b) is a side sectional view showing another example, and the same reference numerals as those in FIG. 9 (a) indicate the same parts, 7a is an introduction passage, 8 is a nozzle, and 9 is a pump.

[0010] This technique is a technique for increasing the height (thickness) of the laminar flow of the molten solder and increasing the velocity of the laminar flow. The increase in the height of the laminar flow is the same as the reason disclosed in Conventional Example 4,
The purpose of increasing the laminar flow speed is to reduce the length of the laminar flow with the aim of relaxing the restrictions on the lengths of the terminals and lead wires of the mounted electronic components that project onto the soldering surface of the wiring board. To suppress. The technical principle is the same as that of the known example 4.

In addition, the technique of the known example 6 is designed to suppress the oxidation of the molten solder, and "a part of the reflux pipe for refluxing the molten solder is provided with an opening so that the molten solder flows higher than the opening. It is a technique of soldering with molten solder. In other words, it is a technique configured so that it does not come into contact with the atmosphere except the opening.

The technique of Known Example 7 is a technique for suppressing soldering spots such as a solder bridge phenomenon and a non-solder phenomenon in a minute / fine portion. That is, a plurality of long wave-forming protrusions of uniform height are formed "continuously" and "perpendicular to the flow of solder" on a substantially "horizontal guide" for the molten solder. To form a wave in the laminar flow to suppress the soldering unevenness.

[0013]

However, the above-mentioned conventional techniques have the following problems.

FIGS. 10 (a) to 10 (c) are views for explaining the problems of the prior art. FIG. 10 (a) is a side sectional view showing an essential part of the known example 1, and FIG. 10 (b) is. FIG. 10C is a side cross-sectional view for explaining the solder swelling phenomenon, and FIG. 10C is a plan view for explaining the solder swelling phenomenon. FIG. 10B is a top view. In addition, in FIG. 10C, the techniques of the known examples 2 and 3 are also illustrated.

That is, in the technique of the known example 1, FIG.
As shown in (a), in order to accelerate the flow velocity of the laminar flow 11a of the molten solder 11 and enhance its action, it is necessary to increase the inclination angle θ of the solder flow plate (the term used in the known example 1) 12. There is. However, as a result, the thickness d of the laminar flow 11a of the molten solder 11 becomes small, and the lengths of the terminals, lead wires, and the like of the mounted electronic components protruding on the soldering surface of the wiring board 13 conveyed in the direction of the arrow A become longer. If long,
There is a problem in that the protruding portion comes into contact with the solder fluid plate 12 and the soldering work cannot be performed.

Further, as shown in FIG. 10 (b), a solder protrusion 11b is formed at a portion where the wiring board 13 and the laminar flow 11a of the molten solder 11 come into contact with each other, and the solder flow velocity at this portion is significantly reduced. There is. That is, due to this phenomenon, the soldering apparatus of this type has a problem that soldering defects such as a solder bridge phenomenon, a flicker phenomenon, and a non-solder phenomenon are likely to occur.

In the techniques of the publicly known examples 2 and 3, as shown in FIG. 10 (c), a part of the laminar flow 11a of the molten solder 11 overflows from the side wall plate 14 and a raised portion 11b of the molten solder 11 is generated. We are trying to reduce the decrease in surface flow velocity. On the other hand, by adjusting the direction, angle, height, etc. of the opening control plate that forms the blowout port of the molten solder 11, the flat plate-shaped portion of the channel-shaped flow passage, and the side wall plate, the thickness of the desired laminar flow of the molten solder and I am trying to get a flow velocity.

However, the basic technique is the same as that of the prior art example 1, and it is basically impossible to increase the laminar flow thickness d of the molten solder, increase the flow velocity, and eliminate the solder rising portion.

In the technologies of Known Examples 4 and 5, the thickness (height) of the laminar flow of the molten solder can be increased, but it is theoretically possible to simultaneously realize the increase of the laminar flow speed. Difficult to do.

That is, as shown in FIGS. 9 (a) and 9 (b), the movement and flow state of the molten solder in the opening 6a, which is the confluent portion of the molten solder jetting upward and the molten solder flowing horizontally, There is no kinetic vector (kinetic energy) that tends to flow in the horizontal direction in the molten solder that is ejected in the upward direction, and the kinetic vector (kinetic energy) of the molten solder that flows in the horizontal direction pushes the molten solder to flow in the horizontal direction. Kinetic energy or motion vector is given.

Therefore, in the merging portion of the opening 6a, a part of the kinetic energy of the laminar flow of the solution solder flowing horizontally into the merging portion is the kinetic energy for flowing the molten solder ejected upward in the horizontal direction. As a result, the laminar flow velocity decreases. And, by that, the thickness (height) of the laminar flow at the confluent portion becomes large. That is, it is theoretically difficult to increase the thickness (height) of the laminar flow and increase the velocity of the laminar flow at the same time.

Further, at the merging portion, the movement direction of the molten solder changes discontinuously with the merging of the molten solder. Therefore, if a large increase in the thickness (height) of the laminar flow is attempted, the surface shape of the laminar flow is disturbed. It will be easier. Further, since the chamber structure is also complicated, the manufacturing work of the device is difficult, and further, the cleaning work of the unnecessary deposits in the chamber which is generated due to the operation of the device is extremely difficult.

In the technique of the known example 6, when the flowing speed of the molten solder is increased, the molten solder overflows from the opening. That is, in this technique, it is necessary to adjust and control the ring flow rate of the molten solder so as not to break the equilibrium point where the molten solder does not overflow from the opening. Further, the limit of the height of the molten solder flowing in a higher position from the opening is basically determined by the surface tension of the molten solder and the material of the reflux pipe member and the molten solder, although it is also affected by the shape of the opening. It is defined by the interfacial tension above which the molten solder cannot be elevated.

That is, it is impossible to increase the thickness of the laminar flow of the molten solder and to increase the speed at the same time.

In the technique of Conventional Example 7, the laminar flow velocity of the molten solder decreases due to the wave-making protrusions.
It is not possible to simultaneously increase the thickness of the laminar flow and increase the speed.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to increase the thickness and velocity of the laminar flow of the molten solder on the solder fluid plate and to obtain the stability of the surface shape. It is an object of the present invention to obtain a soldering method and an apparatus therefor capable of realizing a highly reliable soldering process of a wiring board without causing a soldering defect.

[0027]

SUMMARY OF THE INVENTION According to the present invention, molten solder is once flowed downward to increase its flow velocity and then upwardly flowed, whereby the molten solder has a high flow velocity and a laminar flow with a large thickness. The feature is that both the stable laminar flow surface shape is achieved.

Therefore, in the invention according to the first aspect of the present invention, the molten solder is jetted from the blowout port, and the molten solder flows downward in the first flow guide portion and upwardly flows in the upward direction. The molten solder is guided in a substantially horizontal direction by the flow guide plate in which the rising portion that flows downward again is formed sequentially, and then the laminar flow of the molten solder is formed. The wiring board is conveyed to and the molten solder flowing in the rising portion is brought into contact with the wiring board for soldering.

Further, in the invention according to claim 2, the molten solder is jetted from the blowout port, and the descending portion where the molten solder flows downward, the second flow guiding portion which flows in a substantially horizontal direction, and the upward climbing flow. After that, the laminar flow of molten solder is formed by guiding the molten solder in a substantially horizontal direction by the flow guide plate in which the rising portion that flows downward again is formed sequentially, while the laminar flow of the molten solder is opposite to the flowing direction. The wiring board is conveyed in the direction, and the wiring board and the molten solder flowing in the rising portion are brought into contact with each other for soldering.

Further, in the invention according to claim 3, the molten solder is jetted from the blowing port, and the second flow guiding portion for guiding the molten solder obliquely downward and upwardly flowing and then downwardly rising again. And a portion of the flow guide plate sequentially formed to form a laminar flow of the molten solder, while the wiring board is conveyed in a direction opposite to the direction in which the laminar flow of the molten solder flows, and rises with the wiring board. The soldering is performed by bringing the molten solder flowing through the part into contact.

According to a fourth aspect of the present invention, a flow guide plate for guiding the flow of the molten solder in a substantially horizontal direction to form a laminar flow is provided. The flow guide plate of the descending portion that flows downward and the flow guide plate of the ascending portion that flows upward again after ascending the upward flow are sequentially formed.

Furthermore, the invention according to claim 5 is provided with a fluid guiding fluid which guides the flow of the molten solder in a substantially horizontal direction to form a laminar flow, and the descending part in which the molten solder flows downward through the fluid guiding plate. The flow guide plate, the flow guide plate of the flow guide portion that flows in a substantially horizontal direction, and the flow guide plate of the rising portion that flows upward and then downward again are sequentially formed.

The invention according to claim 6 is provided with a fluid guide for guiding the flow of the molten solder to form a laminar flow,
This fluid guide is disposed obliquely downward, and a flow guide plate of an ascending portion in which the molten solder ascends upward and then flows downward again is provided on the downstream side of the fluid guide.

Further, in the invention as set forth in claim 7, the diversion plates at the descending portion and the ascending portion are formed in a step shape, an inclined shape, or a smooth curved shape.

Further, in the invention as set forth in claim 8, the diversion plate of the rising portion is formed in a step shape, an inclined shape, or a smooth curved shape.

Further, in the invention as set forth in claim 9, the diversion plate of the descending portion and the ascending portion is formed in either an inclined shape or a smooth curved shape, and the top of the diversion plate of the ascending portion is flat. Part is formed.

According to the tenth aspect of the invention, the diversion plate of the rising portion is formed in either an inclined shape or a smooth curved shape, and a flat portion is formed on the top of the diversion plate of the rising portion. It was done.

In the eleventh aspect of the present invention, the fluid guide is formed by a plurality of divertable flow guide plates, and the relative positional relationship between the divided flow guide plates is adjustable and fixed. The fixing means is provided.

Furthermore, the invention according to claim 12 is provided with a fixing means for adjusting the opening height of the blowout port for ejecting the molten solder into the fluid guide.

[0040]

In the invention according to claims 1 and 4 of the present invention, the molten solder flowing down the descending portion has its flow velocity increased and then flows into the ascending portion. At this time, since the molten solder is pooled between the descending portion and the ascending portion, the thickness of the laminar flow does not decrease due to the increased flow velocity in the descending portion. As a result, a thick laminar flow of molten solder can be quickly formed in the rising portion.

Further, in the second and fifth aspects of the present invention, a standing wave is generated in the horizontal portion between the descending portion and the ascending portion as the molten solder descends and rises. This standing wave is generated in alignment, and its wavelength becomes longer as it approaches the rising portion.
Then, when the wiring board comes into contact with the rising portion, this standing wave is generated between the contact portion and the falling portion. As a result, the contact pressure of the molten solder on the wiring board due to the standing wave is further increased.

Further, in the third and sixth aspects of the present invention, the laminar flow velocity of the molten solder is increased by inclining the fluid guide. Since the rising portion is provided on the downstream side of the fluid guide, both the thickness and the speed of the laminar flow of the molten solder flowing through the rising portion can be compatible. The entire fluid guiding portion arranged obliquely constitutes the descending portion, and the descending portion is not provided locally, so that standing waves are hardly generated.

Further, as in the invention described in claims 7 to 10, by selecting various shapes of the diversion plate of the descending portion and the ascending portion, the shape of laminar flow generation can be achieved without breaking the basic shape. It can be adjusted.

If the descending portion is formed in a stepped shape, the kinetic energy of the molten solder in the descending direction increases, and the amplitude of the standing wave can be increased. On the contrary, the amplitude of the standing wave can be reduced by forming it into an inclined shape or a smooth curved shape. That is, this makes it possible to adjust the laminar flow velocity and the acting force of the standing wave.

If the rising portion has a stepped shape, the laminar flow of the molten solder flowing through the rising portion forms a relatively sharp shape, and if it has an inclined shape or a smooth curved shape, it has a relatively gentle roundness. Form a shape.

If a flat portion is formed on the top of the rising portion, the contact time between the laminar flow of the molten solder and the wiring board can be increased.

In the eleventh aspect of the present invention, the flow guide plate is divided into a plurality of parts to facilitate replacement of each part and adjustment of relative positional relationship.
It becomes easier to adjust the laminar flow shape.

According to the twelfth aspect of the present invention, by adjusting the opening height of the blowout opening, it is possible to adjust the thickness and the ejection amount of the laminar flow of the molten solder ejected from the blowout opening. become. That is, it becomes possible to adjust the laminar flow shape.

[0049]

【Example】

[First Embodiment] FIG. 1 is a side sectional view showing a first embodiment of a soldering apparatus for carrying out the soldering method of the present invention, FIG. 2 is a plan view showing a main portion of FIG. 1, and FIG. It is explanatory drawing which shows the aspect of the flow of the molten solder of FIG.

In these figures, 21 is a main part of the soldering apparatus, 22 is a wiring board, and a conveyer 23
Is carried in the direction of arrow A. 24 is molten solder,
It is housed in a solder bath (not shown). Reference numeral 25 is a jet tank, which blows the molten solder 24 with a pump (not shown).
Eject from 6. Reference numeral 27 is a fluid guiding plate, and the flow guiding plates 27A to 27A are provided.
It consists of C. Then, the flow of the molten solder 24 ejected from the blow-out port 26 of the jet tank 25 is guided by the flow guide plate 27A in a substantially horizontal direction, and the arrow B in the direction opposite to the direction in which the wiring board 22 is conveyed.
A laminar flow 24a flowing in the direction is formed. The flow guide plate 27A
Forms a first flow guiding portion 28, a descending portion 29 where the molten solder 24 flows downward at a boundary between the flow guiding plates 27A and 27B, and a second flow guiding portion 30 where the flow guiding plate 27B flows in a substantially horizontal direction.
Then, the molten solder 24 ascends to the upper side and then flows downward again to form the rising portion 31 composed of the flow guide plate 27C. Further, 32 is a side wall plate.

Further, the wiring board 22 is conveyed in the direction of arrow A, which is the opposite direction to the direction of the laminar flow 24a of the molten solder 24 (direction of arrow B), and the molten solder 24 flowing through the wiring board 22 and the rising portion 31. And make soldering.

In this way, the molten solder 24 flowing down the descending portion 29 accelerates its flow velocity and then flows into the ascending portion 31. At this time, since the molten solder 24 is pooled between the descending portion 29 and the ascending portion 31, the thickness of the laminar flow 24a does not decrease due to the increased flow velocity in the descending portion 29. As a result, as shown in FIG. 3, a thick laminar flow 24a (thickness d ₁ ) of the molten solder 24 can be rapidly formed in the rising portion 31.

Between the descending portion 29 and the ascending portion 31, the standing wave 24b is generated as the molten solder 24 descends and rises.
To occur. The standing waves 24b are aligned and generated as illustrated in FIG. 2, and the wavelength thereof becomes longer as it approaches the rising portion 31. That is, the flow rate of the molten solder 24 is further increased in the rising portion 31. Then, when the wiring board 22 comes into contact with the rising portion 31, the standing wave 24b having the phase velocity υ ₃ comes into contact with the soldering surface of the wiring board 2 and is reflected. As a result, the standing wave 24 with respect to the wiring board 22 is
The contact pressure of the molten solder 24 due to b further increases.

On the other hand, in FIG. 3, when the wiring board 22 contacts the molten solder 24 of the rising portion 31, the molten solder 2
The flow velocity υ ₀ of 4 comes into contact with the wiring board 22 and flows away along with υ ₁ in the horizontal direction and υ ₂ in the vertical direction. That is, the motion vector of the molten solder 24 that is pressed against the surface of the wiring board 22,
A motion vector flowing away along the surface of the wiring board 22 can be applied to the soldering surface of the wiring board 22. Therefore, the solderability to the fine and minute portions is enhanced, and the spacing of the molten solder 24 is enhanced. On the other hand, the molten solder 24 that has flowed down the descending portion 29 and reached the height D ₂ is
The height rises to D ₁ at the rising portion 31.

Then, the portion where the laminar flow of the molten solder 24 and the wiring board 22 are in contact with each other is the laminar flow 2 of the rising portion 31 of the height D _1.
4a is at the top and in the vicinity thereof, the lower part 24c in FIG.
Solder swelling does not occur in the portion where the solder is formed. That is, the laminar flow velocity does not decrease at the portion where the laminar flow 24a and the wiring board 22 are in contact with each other.

In this way, a laminar flow of the thick and thick molten solder 24, and a laminar flow 24a generated so as to be inserted into the soldering surface of the wiring board 22 (velocity υ ₀ = υ ₁ + υ ₂ ) can be obtained. A contact portion that does not cause solder swelling, that is, a contact portion that does not cause a decrease in laminar flow velocity, and an increase in contact pressure of the molten solder 24 due to the standing wave 24b causes a long lead wire or the like, that is, a dimension of the soldering surface below the wiring board. Can be applied to the wiring board 22 having a long length, and there is no unsoldered or insufficient solder portion in the fine and minute portions.
Moreover, the solder bridge phenomenon and the flicker phenomenon do not occur. [Second Embodiment] The second flow guide portion 30 between the descending portion 29 and the ascending portion 31 shown in FIG. 1 is removed, and the ascending portion 31 is formed in the next stage of the descending portion 29 to form a soldering apparatus. Make up.
In this case as well, the same operational effects as described above can be obtained. [Third Embodiment] FIG. 4 is a side sectional view showing the shape of the main part of FIG. 1 when it is adjustable. In addition, FIG.
It is a perspective view showing the whole picture of. In these drawings, the same reference numerals as those in FIG. 1 indicate the same parts, that is, the molten solder 2 blown up from the chamber 41 by a pump (not shown).
4 is guided by the guide plate and squirts out from the outlet 26. On the other hand, the fluid guide 27 is composed of three parts, namely, a flow guide plate 27A forming a descending part 29, a flow guide plate 27B forming a substantially horizontal part and a part of the rising part 31, and a rising part 31. Are three parts of the flow guide plate 27C. Each of these parts is fixed by a screw 44 through the long hole 43 so that the size of each part can be easily adjusted and replaced.

Then, the molten solder ejected from the blow-out port 26 is guided to the flow guide plate 27A and forms the desired laminar flow 24a with a descending motion and an ascending motion.

Further, the guide plate 42 forming the blow-out port 26
Screw 44 through a slot (not shown) in chamber 41.
It is fixed so that the opening height can be adjusted. That is, by adjusting the opening height and the pumping power of the pump mechanism, it is possible to adjust the thickness, speed and amount of the molten solder 24 ejected from the blowout port 26.
As a result, the thickness and speed of the laminar flow 24a can be adjusted.

By the way, the fall of the descending part 29 is 1 to 10 m.
m is optimal, and if an extremely large step is provided,
The standing wave 24b shown in (1) becomes unnecessarily large. On the other hand, if it is made extremely small, the action of the descending portion 29 becomes small, and a sufficient effect cannot be expected. The head of the ascending section 31 may be set to the same value as that of the descending section 29, but may be small. If it is extremely increased, the laminar flow velocity of the molten solder 24 flowing through the rising portion 31 tends to be reduced.

In FIG. 4, the flow guiding plate 27B except for the descending portion 29 and the rising portion 31 is arranged to be substantially horizontal, but the molten solder 24 flows through the flow guiding plate 27 as a whole. It is also effective to have a configuration in which it is inclined slightly downward toward the downstream side. That is, the laminar flow velocity can be increased by the amount of the descending slope. Then, in this case, it becomes possible to make the head of the rising portion 31 larger than the head of the descending portion 29 by the amount of the inclination, so that adjustment of the laminar flow 24a
The range of selection can be widened. [Fourth Embodiment] FIG. 6 is a side sectional view showing a fourth embodiment of the present invention.

That is, in this embodiment, the conventional jet nozzle 51 is provided with the fluid guide 27 as the foam forming plate of the molten solder 24. In this example, the flow guide plate 27B is guided as the foam forming plate of the molten solder 24. This is an example in which a flow plate 27C is attached, and the fluid guide 27 is an example of a two-divided configuration.
That is, it is made up of two parts, a descending part 29, a diversion plate 27B forming a part of the second diversion part 30 and the ascending part 31 and a diversion plate 27C forming the ascending part 31, and they are mutually passed through elongated holes. It is fixed with a screw 44.

In this structure, the jet nozzle 51 of the conventional device is used.
There is an advantage that can be used. That is, this can be implemented by providing the fluid guide 27 and the guide plate 42 for guiding the molten solder 24 ejected from the jet nozzle 51 to the flow guide plate 27A side at the tip of the jet nozzle. The guide plate 42 is also fixed with screws 44 through the elongated holes. [Fifth Embodiment] FIG. 7 is a side sectional view showing a fifth embodiment of the present invention.

That is, in this example, instead of providing the descending portion 29 shown in FIG. 6, the diversion plate 27B is inclinedly arranged in the second diversion portion 30, and the molten solder 24 ejected from the blowing port 26 is provided.
The laminar flow 24a is accelerated by this inclination and the rising portion 3
The configuration is such that the laminar flow velocity can be secured by increasing the laminar flow thickness while increasing the thickness of the laminar flow in the recessed portion, that is, the pool portion 24d, immediately adjacent to and immediately below 1. In this example, the standing wave 24b of FIG. 1 hardly occurs.

Incidentally, the flow guide plate 27B is composed of two parts, that is, a descending inclined part, a part forming a part of the rising part 31 and a part forming the rising part 31.

FIG. 8 is a side view showing various modified shapes of the fluid guide 27 of FIG. 1, and the basic shape is as shown in FIG. FIGS. 8A to 8E are views for explaining the deformation of the descending portion 29 and the ascending portion 31.

In FIG. 1 showing the basic shape, a stepped descending portion 29 and a smooth curved rising portion 31 are combined.

Next, FIG. 8A shows an example in which the rising surface of the rising portion 31 is formed in an inclined shape 61, and FIG. 8B shows an example in which a flat portion 62 is formed on the top of the rising portion 31, FIG. c) is the descending part 2
9 is formed in an inclined shape 63, FIG.
Is an example in which a smooth curved line 64 is formed. Also, FIG.
(E) is an example in which the descending portion 29 and the ascending portion 31 are continuously formed in a smoothly curved curved shape 65.

That is, with such a variation, the details of the laminar flow shape can be adjusted without changing the basic type of the laminar flow 24a. In the example of FIG. 8E, the standing wave 24b of FIG. 1 hardly occurs.

For example, if the descending portion 29 has a stepped shape, the kinetic energy of the molten solder 24 in the descending direction increases, and the rate of increase of the laminar flow velocity and the amplitude of the standing wave 24b can be increased. On the other hand, if it is inclined or has a smooth curve, the amplitude of the standing wave 24b can be reduced without changing the rate of increase of the laminar flow velocity. That is, these can adjust the laminar flow velocity and the acting force of the standing wave 24b.

Of course, the magnitude of the drop of the descending portion 29 affects the rate of increase of the laminar flow velocity and the amplitude of the standing wave 24b.

On the other hand, if the rising portion 31 has a stepped shape, the laminar flow 24a of the molten solder 24 flowing through the rising portion 31 forms a relatively sharp shape, and if it has an inclined shape or a smooth curved shape, it forms a relative shape. Form a gentle rounded shape. These shapes are selected according to the unevenness ratio of the soldering surface of the board 22 even if the wiring board 22 has the same fine pitch (the area of the soldering lands is small and the interval between the soldering lands is small). Good to do.

For example, since surface mount type parts (chip parts) in which the mounting heights of electronic parts are not uniform are often used,
If the wiring board 22 having a large unevenness ratio is to be soldered, a stepped shape is selected. That is, this allows the molten solder 24 to enter the portion forming the deep recess. On the other hand, in the case of a wiring board in which the mounting heights of the surface-mounted electronic components are small and uniform, that is, in the case of the wiring board 22 having a small unevenness ratio, an inclined or curved shape is selected. That is, a relatively stable laminar flow can provide uniform solder wettability as compared with the case of the step shape.

If the flat portion 62 is formed on the top of the rising portion 31, the laminar flow 24a of the molten solder 24 and the wiring board 22 are formed.
The contact time can be made large. This is for example
This is effective when the (statistical) deviation of the heat capacity of each electronic component mounted on the wiring board 22 is large. That is, when there is an electronic component having a soldering terminal or a lead wire having a large deviation and a large heat capacity, the long contact time between the laminar flow 24a and the wiring board 22 means that sufficient heating time for the component is obtained. Is that you can
Therefore, good solder wettability can be obtained even in the component.

[0074]

As described above, the invention according to claim 1 according to the present invention is characterized in that molten solder is jetted from a blow port,
The molten solder is guided in a substantially horizontal direction by a flow guide plate in which a descending portion in which the molten solder flows downward in the first flow guide portion and an upward portion in which the molten solder flows upward and then flows downward again are formed in order. A laminar flow of molten solder is formed, while the wiring board is conveyed in the direction opposite to the direction in which the laminar flow of molten solder flows, and the wiring board and the molten solder flowing in the rising portion are brought into contact with each other to perform soldering. Therefore, since the molten solder is pooled between the descending portion and the ascending portion, the thickness of the laminar flow does not decrease due to the increased flow velocity in the descending portion. As a result, a thick laminar flow of molten solder can be quickly formed in the rising portion. The solderability for fine and minute parts is improved, and the separation of molten solder is also improved.

Further, in the invention according to claim 2, the molten solder is jetted from the blowout port, and the descending portion in which the molten solder flows downward, the second flow-inducing portion flowing in a substantially horizontal direction, and the upward climbing flow. After that, the laminar flow of molten solder is formed by guiding the molten solder in a substantially horizontal direction by the flow guide plate in which the rising portion that flows downward again is formed sequentially, while the laminar flow of the molten solder is opposite to the flowing direction. The wiring board is conveyed in the direction, and the wiring board and the molten solder flowing in the rising portion are brought into contact with each other to perform soldering, so a standing wave is generated as the molten solder descends and rises, and the wiring board This standing wave with respect to increases the contact pressure of the molten solder further.

Further, in the invention as set forth in claim 3, the molten solder is jetted from the blowout port, and the second guiding portion for guiding the molten solder obliquely downward and upwardly flowing and then downwardly rising again. And the guide portion are sequentially formed to form a laminar flow of the molten solder, while the wiring board is conveyed in a direction opposite to the direction in which the laminar flow of the molten solder flows, and rises with the wiring board. Since the molten solder flowing in the rising part is contacted for soldering, the molten solder is pooled in the position immediately before the rising part, and the thickness of the laminar flow of the molten solder flowing in the rising part is secured and the speed is increased. Can be compatible.

The invention described in claim 4 can realize the soldering method of the invention described in claim 1.

Furthermore, the invention described in claim 5 can realize the soldering method of the invention described in claim 2.

The invention described in claim 6 can realize the soldering method of the invention described in claim 3.

Further, in the invention as set forth in claim 7, since the flow guide plates of the descending portion and the ascending portion are formed in either a step shape, an inclined shape or a smooth curved shape, the descending portion and the ascending portion are formed. The laminar flow generation shape can be adjusted without breaking the basic shape by selecting various shapes.

Further, in the invention according to claim 8, since the flow guide plate of the rising portion is formed in any of a step shape, an inclined shape and a smooth curved shape, various shapes of the rising portion can be selected. , It is possible to adjust the laminar flow generation shape without breaking the basic shape.

According to the ninth aspect of the invention, since the flow guide plates of the descending portion and the ascending portion are formed in an inclined shape or a smooth curved shape, and further, a flat portion is formed at the top of the ascending portion. , It is effective when there is an electronic component equipped with a soldering terminal or a lead wire that has a large thermal capacity that jumps out as compared with the average thermal capacity of the electronic component mounted on the fine pitch wiring board, and it is also sufficient in that part. It becomes possible to obtain solder wettability.

According to the tenth aspect of the invention, the diversion plate of the rising portion is formed in either an inclined shape or a smooth curved shape, and a flat portion is formed on the top of the diversion plate of the rising portion. Therefore, compared to the average heat capacity of the electronic components mounted on the fine-pitch wiring board, it is effective when there is an electronic component with a soldering terminal or lead wire that has a large heat capacity that jumps through. Also, it becomes possible to obtain sufficient solder wettability.

Further, in the invention as set forth in claim 11, the fluid guiding fluid is formed so as to be dividable, and a fixing means for fixing the relative positional relationship of each of the divided fluid guiding plates in an adjustable manner is provided. Therefore, by adopting a configuration in which the fluid guide is divided into a plurality of parts, it becomes easy to replace each part and adjust the relative positional relationship, and it becomes easy to adjust the laminar flow shape. That is, it becomes possible to form an optimum laminar flow with respect to wiring boards having different characteristics.

Further, according to the twelfth aspect of the invention, since the opening height of the blowout port for ejecting the molten solder to the flow guide plate can be adjusted, by adjusting the opening height of the blowout port,
It becomes possible to adjust the thickness and the amount of the laminar flow of the molten solder ejected from the blowing port. That is, it becomes possible to adjust the laminar flow shape.

As described above, according to the present invention, it is possible to solder a terminal of a mounted electronic component or a wiring board having a long protruding length of a lead wire on the soldering surface side. It has various advantages such as a highly reliable soldering process for a wiring board which does not cause soldering defects such as insufficient wettability, a bridging phenomenon and a crackling phenomenon.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a first embodiment of the present invention.

FIG. 2 is a plan view showing a main part of FIG.

FIG. 3 is an explanatory diagram showing a flow mode of the molten solder in FIG. 1.

FIG. 4 is a side sectional view showing the shape of the main part of FIG. 1 when it is adjustable.

5 is a perspective view showing the whole of FIG. 4. FIG.

FIG. 6 is a side sectional view showing a second embodiment of the present invention.

FIG. 7 is a side sectional view showing a third embodiment of the present invention.

8 is a side view showing the shape of the flow guide plate of FIG. 1. FIG.

FIG. 9 is a side view showing an example of a conventional soldering device.

FIG. 10 is a side view showing another example of a conventional soldering device.

[Explanation of symbols]

 21 Soldering Device 22 Wiring Board 23 Transport Conveyor 24 Molten Solder 24a Laminar Flow 24b Standing Wave 25 Jet Tank 26 Blowout 27 Conductive Fluid 27A Guide Plate 27B Guide Plate 27C Guide Plate 28 First Guide Section 29 Descent Part 30 Second diversion part 31 Ascending part

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[Procedure amendment]

[Submission date] February 2, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

Further, FIG. 9 (b) is a side sectional view showing another example, and the same reference numerals as those in FIG. 9 (a) indicate the same portions, and 7 and 7a.
Is an introduction passage, 8 is a nozzle, and 9 is a pump.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Therefore, at the merging portion of the opening 6a, a part of the kinetic energy of the laminar flow of the molten solder flowing horizontally into the merging portion is the kinetic energy for flowing the molten solder ejected upward to the horizontal direction. As a result, the laminar flow velocity decreases. And, by that, the thickness (height) of the laminar flow at the confluent portion becomes large. In other words, it is theoretically difficult to achieve both increasing the thickness (height) of the laminar flow and increasing the velocity of the laminar flow.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Change

[Correction content]

Between the descending portion 29 and the ascending portion 31, the standing wave 24b is generated as the molten solder 24 descends and rises.
To occur. The standing waves 24b are aligned and generated as illustrated in FIG. That is, the flow rate of the molten solder 24 is further increased in the rising portion 31. Then, when the wiring board 22 comes into contact with the rising portion 31, the standing wave 24b having the phase velocity υ ₃ comes into contact with the soldering surface of the wiring board 22 and is reflected. As a result, the standing wave 2 with respect to the wiring board 22 is
The contact pressure of the molten solder 24 due to 4b further increases.

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

[Procedure Amendment 5]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction content]

[Figure 7]

Claims (12)

[Claims] 1. A laminar flow of the molten solder is guided downward in the laminar flow of the molten solder by forming a laminar flow of the molten solder by guiding the molten solder ejected from the blow port in a substantially horizontal direction with the fluid. Flow downwards, then upward in the rising portion of the fluid guide and then downward again, while carrying the wiring board in the direction opposite to the direction in which the laminar flow of the molten solder flows, and Soldering is performed by bringing the molten solder flowing through the rising portion into contact with the solder. 2. When the molten solder ejected from the blow-out port is guided by the fluid in a substantially horizontal direction to form a laminar flow of the molten solder and soldering is performed, the laminar flow of the molten solder descends from the fluid. Flow downward in the horizontal direction, then flow in a substantially horizontal direction in the horizontal portion of the fluid guide, then upward in the rising portion of the fluid guide and then flow downward again, while a laminar flow of the molten solder flows. The soldering method is characterized in that the wiring board is conveyed in a direction opposite to the direction, and the wiring board and the molten solder flowing in the rising portion are brought into contact with each other to perform soldering. 3. When the molten solder ejected from the blow-out port is guided in a substantially horizontal direction with a guiding fluid to form a laminar flow of the molten solder for soldering, the laminar flow of the molten solder After flowing obliquely downward in the inclined portion, it flows upward again in the rising portion of the fluid guide and then flows downward again, while conveying the wiring board in the direction opposite to the direction in which the laminar flow of the molten solder flows, Soldering is performed by bringing this wiring board into contact with the molten solder flowing in the rising portion. 4. A soldering device provided with a fluid guiding fluid that guides the flow of molten solder in a substantially horizontal direction to form a laminar flow, wherein the fluid guiding fluid is provided at a descending portion where the molten solder flows downward. A soldering device characterized in that a flow plate and a flow guide plate of an ascending portion which flows upward and then downward again are sequentially formed. 5. A soldering apparatus provided with a fluid guide for guiding a flow of molten solder in a substantially horizontal direction to form a laminar flow, wherein the fluid is a descending portion where the molten solder flows downward. The flow guide plate, the flow guide plate of the flow guide portion that flows in a substantially horizontal direction, and the flow guide plate of the rising portion that flows upward and then downward again are sequentially formed. Soldering equipment. 6. A soldering apparatus provided with a fluid guiding fluid for guiding a flow of molten solder in a substantially horizontal direction to form a laminar flow, wherein the fluid guiding fluid is arranged obliquely downward. A soldering device, wherein a flow guide plate of an ascending portion where the molten solder flows upward after flowing upward is provided on the downstream side of the fluid guide. 7. The flow guide plate of the descending portion and the ascending portion is formed in any of a step shape, an inclined shape, and a smooth curved shape, according to claim 4 or claim 5. Soldering equipment. 8. The soldering device according to claim 6, wherein the flow guide plate of the rising portion is formed in a step shape, an inclined shape, or a smooth curved shape. 9. The diversion plate of the descending portion and the ascending portion is formed in either an inclined shape or a smooth curved shape, and a flat portion is formed on the top of the diversion plate of the ascending portion. The soldering device according to claim 4 or claim 5. 10. The flow guide plate of the rising portion is formed in either an inclined shape or a smooth curved shape, and a flat portion is formed on the top of the flow guide plate of the rising portion. 6. The soldering device according to 6. 11. The guiding fluid is formed of a plurality of divertable flow guide plates, and a fixing means is provided for fixing the relative positional relationship of the divided flow guide plates in an adjustable manner. The soldering device according to any one of claims 4 to 10, which is characterized. 12. The soldering device according to claim 4, wherein the blowout port for ejecting the molten solder to the fluid guiding side is formed so that its opening height can be adjusted. .