JP2000042731A - Solder application device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solder application device which facilitates control of the height of a top part of a rising flow of a solder with simple constitution, is capable of correcting and keeping a solder surface parallel to a back side of a printed circuit board at the time of generation of an inclined solder surface, and favorable from the stand point of manufacturing cost. SOLUTION: Relating to a solder application device 1 that an application area 60 of a member 6 to which a solder is applied is brought into contact with a top part a5 of a rising flow a2 of a solder A to be guided by a nozzle 5, the nozzle 5 is provided with adjustment holes 56, 57 for returning a part of the rising flow a2 of the solder A to a storage hole 2 below a liquid solder surface S1 to divide the rising flow a2 of the solder A into a portion overflowing form the top part a5 and portions a3, a4 flowing out of the adjustment holes 56, 57.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus which can be used when soldering is performed on a back side of a printed circuit board in which electronic components are arranged on both sides.

[0002]

2. Description of the Related Art (1) As shown in FIG. 5, for example, there is known a solder coating apparatus 1A used for coating solder on the back surface 60 side of a printed circuit board 6. The solder application device 1A includes a housing portion 2a for housing the molten solder A, and a pump portion 3a disposed below the constant liquid level S1 of the solder A in the housing portion 2a and generating a solder flow a10.
And the solder A sent by the drive of the pump section 3a,
Ascending flow a2 arriving at a predetermined height from constant liquid level S1 via current plate 5c having a plurality of through holes 50c having the same hole diameter.
0 and guide the upward flow a20 to the constant liquid level S1.
A nozzle 5A that overflows at a higher position and returns to the housing portion 2a, and the back surface 60 side of the printed circuit board 6 is brought into contact with the jet top a21 of the upward flow a20.

[0003] However, the solder coating apparatus 1A is provided with a printed circuit board 6 on the top a21 of the upward flow a20 of the solder A.
5, a slanted liquid surface T1 having height differences h1 and h2 is formed in a width direction Z orthogonal to a transfer direction P (a transfer direction from the depth side to the front side in FIG. 5), and thus the back surface to which the solder is applied. 60 cannot be applied uniformly over the entire area. The reason why the inclined liquid surface T1 is formed is that a pressure difference is generated in the upward flow a20 in the nozzle 5A along the width direction Z of the printed circuit board 6.

[0004] That is, in the nozzle 5A, the momentum of the basin guided along the vertical wall 52a at a position distant from the pump portion 3a increases, and conversely, the flow is guided along the vertical wall 53a at a position near the pump portion 3a. The power of the basin to be drained becomes small, and this difference becomes the height difference h1, h2 at the top a21 of the ascending flow a20 to form the inclined liquid surface T1. (2) Then, the top a2 of the upward flow a20 of the molten solder A
Various correction means have been disclosed for correcting the surface of the printed circuit board 1 parallel to the back surface 60 of the printed circuit board 6 (Japanese Utility Model Application Laid-Open No. 63-1).
No. 6550, Japanese Utility Model Laid-Open No. 3-14058).

As shown in FIG. 6 as a typical example, the conventional correction means uses the diameter of a through hole 50d formed in a rectifying plate 5d disposed below the inside of a nozzle 5A as a pump part 3a.
The height difference h1, h2 (see FIG. 5) of the top part a21 of the upward flow a20 is corrected by distributing the arrangement such that the distribution is smaller at a further position and larger at a position closer to the pump unit 3a. On the other hand, a parallel liquid surface T is formed.

[0006]

However, the configuration shown in FIG. 6 described above, the rectifying grid disclosed in Japanese Utility Model Application Laid-Open No. 63-16550, and the first configuration disclosed in Japanese Utility Model Application Laid-Open No. 3-14058. In a configuration in which the straightening plate and the second straightening plate are used with the through-holes in phase, the position of each through-hole, the size and shape of the opening, etc. are fixed at predetermined positions. In the case where there is a delicate variation in the shape of the head and the control of the driving state of the pump, the variation is reflected (affected) as a variation phenomenon of the height of the top.

For this reason, it is difficult to correct the parallel liquid level T by an external adjustment operation every time a phenomenon occurs in which the height of the top of the back surface 60 of the printed circuit board 6 varies. Japanese Utility Model Application Laid-Open No. 4-43459 discloses a plate-shaped damper that can be rotated in a nozzle in a jet-type soldering apparatus for the purpose of forming a jet wavefront corresponding to the angle of a transfer trajectory of a printed circuit board. Is disclosed, but using this configuration, FIG. 5 and FIG.
The inclined liquid surface T inclined with respect to the back surface 60 of the printed circuit board 6 in a direction Z orthogonal to the transport direction P of the printed circuit board 6 shown in FIG.
It is difficult to correct 1 to the parallel liquid level T.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a simple structure in which the height of the top of the upward flow of solder is easily controlled, and even when an inclined liquid level is generated, it is easily handled. An object of the present invention is to provide a solder coating apparatus which can maintain a liquid level parallel to the back surface of a printed circuit board and is advantageous in manufacturing cost.

[0009]

SUMMARY OF THE INVENTION According to the present invention, there is provided a solder applying apparatus, comprising: an accommodating section for accommodating a molten solder; and a pump section arranged below the liquid level of the solder in the accommodating section to generate a flow of the solder. A nozzle for guiding the solder as an ascending flow reaching a predetermined height position from the liquid level by driving the pump unit, and for allowing the ascending flow to overflow at a position higher than the liquid surface and return to the storage unit. A solder application device for contacting an application area of a solder application target member with a top of the ascending flow of the solder guided by the nozzle, wherein the nozzle applies a part of the ascending flow of the solder to the liquid. An adjustment hole for returning the solder to the housing portion below the surface is provided, and the upward flow of the solder is divided into a portion overflowing from the top portion and a portion exiting from the adjustment hole.

[0010]

According to the solder coating apparatus of the present invention, the molten solder is stored in a predetermined amount in the storage section and the liquid level at a predetermined height is maintained by driving the pump section. After being guided by the nozzle as an ascending flow reaching a predetermined height position, it overflows at a position higher than the liquid level, returns to the accommodation section, and forms a flow of the circulating system that becomes the ascending flow again by driving the pump section. .

Here, according to the solder coating apparatus of the present invention, the nozzle is provided with an adjustment hole for returning a part of the rising flow of the solder to the accommodation portion below the liquid level, and the rising flow of the solder overflows from the top. The height of the top of the ascending flow (jet height) can be reduced according to the purpose, so that the area of the application area of the soldering target member can be reduced. Can be corrected to a parallel liquid surface.

Further, even if the influence of the fluctuation of the driving of the pump section and the difference or change in the internal shape of the nozzle is reflected as the inclined liquid level at the top of the rising flow of the solder, it is easy. It can be corrected and can have a parallel liquid level. Therefore, with respect to the coating target surface of the coating target member,
The entire area can be uniformly contacted with the top of the ascending flow of solder, and can be applied efficiently.

Further, since the solder returned from the adjusting hole to the accommodation portion flows below the liquid level, it does not need to come into contact with air and does not create a state of being newly oxidized. This effect can be further increased by using a guide cover that guides the return flow from the adjustment hole to the storage section in a direction opposite to the constant liquid level side. The nozzle overflows the upward flow of the solder and returns it to the housing portion, and has an upper opening facing the application area of the solder application target member. The upper opening has an opening width in a direction intersecting the conveying direction of the application target member that is longer than the width of the application target member.

The nozzle guides the solder as an ascending flow that reaches a predetermined height from the liquid level by driving the pump unit, and guides a substantially horizontal flow of the solder supplied from the pump unit. An integral type formed integrally with the jet duct forming the passage, or a split type detachably mounted on the jet duct can be used.

In the case of using a split type nozzle as the nozzle, a maintenance work for removing the inner wall surface of the nozzle forming the passage of the solder, the current plate disposed inside the nozzle, and the slag adhered to the periphery thereof, Work can be done quickly during inspection work. In the present invention, the nozzle includes a region for guiding the solder as an upward flow. For example, if the jet duct forms an upward flow guide region for guiding the solder as an upward flow, the upward flow guide region The term including is referred to.

The adjusting hole is provided at least at a position separated from the pump portion of the nozzle at a position below the liquid surface of the wall member extending upward and communicating with the housing portion. Along with this, a second adjustment hole may be provided at a position close to the pump portion of the nozzle, at a position communicating with the housing portion below the liquid level of the wall member extending upward, and at the first adjustment hole and the target position. preferable. In this case, since the nozzle can adjust and control the return flow rate of the solder flowing out of the adjustment holes at two different positions, that is, a position farther from the pump unit and a position closer to the pump unit, to the accommodation unit,
The inclined liquid level can be more easily corrected to the parallel liquid level.

The adjusting hole may be a horizontal rectangle, a horizontal circle, a plurality of circles or squares arranged at predetermined intervals in the horizontal direction. Further, it is preferable that the adjustment hole is provided with an opening / closing member capable of freely adjusting the opening area by an external operation.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG.
A description will be given based on FIG. The solder coating apparatus 1 in the embodiment shown in FIG. 1 and FIG. 2 is arranged below a container 2 for accommodating the molten solder A and below a constant liquid level S1 of the solder A in the container 2 and controls the flow of the solder A. A rotating blade 3 (see FIG. 2) as a pump section to generate, a jet duct 4 for guiding the solder A in a substantially horizontal direction by driving the rotary blade 3, and a horizontal flow a1 of the solder A guided by the jet duct 4 ( 2) is converted into ascending flow a2, and is formed on the back surface (lower surface) 60 of the printed circuit board 6 conveyed to the conveyance path P, on the way to form the top a5 reaching the solder application position S2. The return flow a3, a4 and the transport path P from the position S2
And a nozzle 5 for dividing the flow into a flow a6 that flows back and forth back to the storage section 2 before and after the above.

The housing portion 2 previously stores an amount of the molten solder A that holds a constant liquid level S1 set at a predetermined height. The housing section 2 has a heating section (not shown) for heating the solder A to a molten state. As the solder A is consumed, the solder A is replenished to the container 2 at appropriate times so as to maintain the constant liquid level S1. The rotor 3 is provided at a position where the molten solder A is stirred below the constant liquid level S1. The rotary wing 3 includes an electric motor 31 that transmits and applies a rotational driving force to a rotary shaft 30 thereof.

The jet duct 4 is, as shown in FIG.
A substantially cylindrical L-shaped horizontal position guide 40 disposed below the constant liquid level S1 of the solder A in the housing 2 and a vertical position guide connected to extend substantially vertically; Part 41
And The lateral position guide section 40 has the rotating blade 3 disposed on one end 40 a side and the rotating shaft 30 of the rotating blade 3.
Is provided with a solder inlet 40b which is open at a predetermined interval. The other end 40c side of the horizontal position guide 40 communicates with the vertical position guide 41.

The nozzle 5 is a tubular body detachably mounted on the vertical position guide 41 of the jet duct 4, and has a rectangular lower opening 50 communicating with the vertical position guide 41 of the jet duct 4. An upper opening 51 substantially similar in shape to the lower opening 50 and having an opening area smaller than the lower opening 50;
Vertical wall portions 52 and 53 forming two short sides facing each other and the inclined wall portions 54 and 55 forming two long sides and the vertical wall portions 52 and 53 facing each other. And rectangular adjustment holes 56 and 57.

The lower rectifying plate 5a and the upper rectifying plate 5b are respectively provided inside the nozzle 5 at predetermined intervals in parallel.
And are arranged. Lower current plate 5a and upper current plate 5b
Are provided with a large number of flow straightening holes. The one adjustment hole 56 is provided at the vertical wall 5 at a position away from the rotor 3.
2 is provided at a position below the constant liquid level S1 and communicates with the storage section 2. The other adjustment hole 57 is provided at a position close to the rotary wing 3 and below the constant liquid level S1 of the vertical wall surface 53 so as to communicate with the container 2.

The adjusting holes 56, 57 are provided with plate-shaped opening / closing lid members 58, 59 in a sliding manner interlocking with an operation member (not shown) operable from the outside of the housing portion 2. The opening areas of the adjustment holes 56 and 57 can be reduced or widened according to the purpose by the opening and closing lid members 58 and 59. According to the solder coating apparatus 1 configured as described above, the back surface (lower surface) 60 side of the printed circuit board 6 in which electronic components (not shown) are arranged on the front and back surfaces is set as a solder application region,
Used when soldering.

In the solder applying apparatus 1 of the embodiment, a predetermined amount of the molten solder A is accommodated in the accommodating section 2 and held at the constant liquid level S1. Next, the solder A in the jet duct 4 is agitated below the constant liquid level S1 by the rotating blades 3 driven to rotate by the electric motor 31. Then, the solder A is urged, forms a substantially horizontal flow a1, and is vigorously fed from the horizontal position guide 40 of the jet duct 4 to the vertical position guide 41.

The horizontal flow a1 is guided by the horizontal position guide section 40 and then guided by the vertical position guide section 41 to change direction to become an upward flow a2. This ascending flow a2
During the ascent while being guided by the nozzle 5, the flows a3 and a4 returning from the adjusting holes 56 and 57 to the storage section 2 under the constant liquid level S1 and returning from the upper opening 51 while further rising within the nozzle 5 Overflows before and after road P,
When it reaches a position higher than the upper opening 51 (a predetermined height h from the constant liquid level S1 shown in FIG. 2), the back surface 60 of the printed circuit board 6 is reached.
After that, the flow is returned to the flow a6 (see FIG. 1) returning to the storage section 2.

On the other hand, the storage portion 2
In the flows a3 and a4 returning to the above, the ratio of the return amounts can be changed by performing the operation of adjusting the opening areas of the adjustment holes 56 and 57 by the opening and closing lid members 58 and 59. Therefore, by the operation of adjusting the opening and closing lid members 58 and 59,
In the nozzle 5, the pressure of the upward flow a2 along the side of the vertical wall 52 away from the rotary blade 3 is reduced, and the pressure of the upward flow a2 along the side of the vertical wall 53 near the rotary blade 3 is increased. Can be controlled to

In this case, two different positions are simultaneously adjusted at the position of the nozzle 5 on the side of the vertical wall 52 away from the rotor 3 and the position of the nozzle 5 on the side of the vertical wall 53 near the rotor 3. Since the flow rate of the solder flowing out of the holes 56 and 57 and returning to the accommodating portion 2 can be adjusted and the pressure of the ascending flow a2 can be controlled, the level of the top portion a5 of the ascending flow a2 (jet height) is changed to change the liquid level. The problem that S1 becomes the inclined liquid surface T1 with respect to the back surface 60 of the printed circuit board 6 can be easily corrected to the parallel liquid surface T by stabilizing the variation small and uniform.

After the upward flow a2 is separated into flows a3 and a4 by the upper guide cylinder 4c of the nozzle 5, the upward flow a2
And the horizontal position guide section 40 is returned from the solder inlet 40b again.
And the flow of the circulation system which is urged by the rotary wings 3 to form the horizontal flow a1 is repeatedly formed. According to the solder application device 1 of the embodiment, the nozzle 5 includes the adjustment holes 56 and 57 at two different positions for returning a part of the ascending flow a2 of the solder A to the accommodation portion 2 below the constant liquid level S1.

Then, the accommodation portion 2 is inserted through the adjustment holes 56 and 57.
A3 and a4 flowing out of the container, and a flow a6 that overflows from the upper opening 51 to the front and rear of the transport path P and returns to the storage unit 2.
And can be divided into For this reason, for example, the resistance of the flow of the solder A corresponding to the change in the rotational drive of the electric motor M and the change in the internal shape and size specifications of the nozzle 5 and the jet duct 4 is reflected (influenced), and the printed board 6 Even when the inclined liquid surface T1 is generated along the longitudinal direction of the upper opening 51 orthogonal to the transport direction P of the printed circuit board 6 at the application position S2 of the solder A on the back surface 60,
By controlling the flow rates of the flows a3 and a4 returning to the storage section 2, the pressure of the flow a6 returning to the storage section 2 can be adjusted, and the liquid level T can be easily corrected to the parallel liquid level T with respect to the back surface 60 of the printed circuit board 6. .

Therefore, in the case of the solder coating apparatus 1 of the embodiment, the top part a5 of the rising flow a2 of the solder can be uniformly contacted with the entire back surface 60 of the printed board 6,
And it can apply efficiently. Further, adjustment holes 5
The return flows a3 and a4 coming out of the storage portions 2 from 6 and 57 become flows below the constant liquid level S1 and do not generate a jet on the constant liquid level S1, so that they do not come into contact with air and are newly oxidized. An effect that does not create such a state can be obtained.

Incidentally, as shown in FIG.
The guide cover 52a (5) that guides the return flow a3 (a4) exiting from (57) to the storage unit 2 in the direction opposite to the constant liquid level S1 side.
By using 3a), the above effect can be further enhanced. Further, the solder coating device 1 in the above embodiment
Then, in order to return a part of the upward flow a2 of the solder A formed in the nozzle 5 to the accommodating portion 2 below the constant liquid level S1 on the way to the upper opening portion 51, the opposing 2 At opposite positions of vertical wall portions 52, 53 forming two short sides,
The case where the adjusting holes 56 and 57 are provided is shown, but the present invention is not limited to this. The upper opening 51 is formed only by the adjusting hole 56 provided on the vertical wall 52 side at a position away from the rotor 3. The liquid level T can be corrected slightly above the parallel liquid surface T with respect to the back surface 60 of the printed circuit board 6.

[0032]

According to the solder application apparatus of the present invention, the nozzle for guiding the upward flow of the solder is provided with an adjustment hole for returning a part of the upward flow of the solder to the receiving portion below the liquid level, and Is divided into a portion that overflows from the top and a portion that comes out of the adjustment hole (a portion that returns to the storage portion).

For this reason, for example, the rising flow of the solder in the nozzle generates a pressure difference between a region distant from the pump portion and a region close to the pump portion. Even if the top of the member is inclined with respect to the surface to be coated of the member to be soldered, the pressure of the upward flow can be adjusted by controlling the amount coming out of the adjustment hole (the amount returned to the housing portion), and Fluctuations can be reduced and the top liquid surface can be corrected to be parallel to the surface to be coated.

Accordingly, in the case of the solder coating apparatus of the present invention, the entire surface of the coating target surface of the coating target member is
The top of the ascending flow of solder can be uniformly contacted and can be applied efficiently. Furthermore, since the solder returned from the adjustment hole to the accommodation portion flows below the liquid level, it does not need to come into contact with the atmosphere and does not need to create a new oxidation state.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view schematically illustrating a solder coating apparatus according to an embodiment.

FIG. 2 is a sectional view taken along the line aa in FIG. 1 showing a flow of solder in the solder coating apparatus of the embodiment.

FIG. 3 is a perspective view schematically illustrating a main part of a solder coating apparatus according to the embodiment.

FIG. 4 is a sectional view showing a state in which a guide cover is used above an adjustment hole of the solder application device in FIG. 2;

FIG. 5 is a cross-sectional view showing a flow of solder in the solder coating apparatus of Conventional Example 1.

FIG. 6 is a cross-sectional view showing a flow of solder in a solder coating apparatus of Conventional Example 2.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Solder applicator 2 ... Housing part 3 ... Rotor blade as a pump part 4 ... Jet duct 5 ... Nozzle 50 ... Lower opening 51 ... Upper opening 52, 53 ... Vertical wall 56, 57 ... Adjusting holes 58, 59 … Opening / closing lid member A… Solder in molten state S1… Solder constant liquid level S
2 ... Solder application position T ... Solder top liquid surface parallel to the lower surface of the substrate to be applied T1 ... Solder top liquid surface inclined to the lower surface of the substrate to be applied a1 ... Almost horizontal flow a2 ... Ascending Flow a3, a4: Flow returning from the nozzle adjustment hole to the storage section
a5: Top part a6: Flow returning from the upper opening of the nozzle to the storage part

Claims (1)

[Claims] An accommodating section for accommodating the molten solder; a pump section disposed below the liquid level of the solder in the accommodating section to generate a flow of the solder; and driving the pump section to move the solder to the liquid level. A nozzle that guides the upward flow to reach a more predetermined height position, overflows the upward flow at a position higher than the liquid level, and returns the upward flow to the housing portion. A solder coating device for contacting a coating area of a solder application target member with a top of an ascending flow, wherein the nozzle includes an adjustment hole that returns a part of the ascending flow of the solder to the storage portion below the liquid level. A solder applicator, wherein the ascending flow of the solder is divided into a portion that overflows from the top portion and a portion that flows out of the adjustment hole.