JP3370849B2 - Reflow soldering equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan for agitating an atmosphere or an atmosphere circulation of solder which has been supplied in advance to a soldered portion of a workpiece to be soldered, such as a wiring board having electronic parts mounted thereon. The present invention relates to a reflow soldering device that heats and melts with a heating device equipped with a blower fan for soldering, and solders a soldered portion.

[0002]

2. Description of the Related Art A reflow soldering apparatus heats a wiring board by irradiating infrared rays or blowing hot air to melt the solder previously supplied to a soldered portion on which electronic components are mounted, It is a device for attaching. Then, in an apparatus for collectively reflow soldering the parts to be soldered, an infrared heater is generally provided in a heating furnace such as a chamber, or a heater and a blower fan for blowing hot air are provided. ing.

The blower fan is used for the purpose of agitating the atmosphere in the furnace so as to obtain a uniform temperature distribution and for the purpose of blowing the atmosphere heated by the heater as hot air to the wiring board. There are cases.

3 (a) and 3 (b) are side sectional views showing an example of a conventional reflow soldering apparatus using an axial flow type fan, and FIG. 3 (a) is mainly used for stirring the atmosphere. FIG. 3B is a diagram showing an example in which the hot air is blown to the wiring board and is circulated for the main purpose.

The heating furnace 3 of the reflow soldering apparatus generally has a structure in which a plurality of heating chambers 5, 6 and 7 formed by the furnace body 4 are provided along the transfer path of the transfer conveyor 2. With the configuration, the wiring board 1 can be continuously soldered, and the controllability of the heating profile is improved. Figure 3 (a),
The example of (b) is an example of a reflow soldering apparatus including a temperature raising part heating chamber 5, a temperature equalizing part heating chamber 6 and a reflow part heating chamber 7.

The reflow soldering apparatus shown in FIG.
The wiring board 1 is heated by the infrared rays emitted from the heater 8, and the atmosphere in the heating chambers 5, 6, 7 is agitated by an agitating axial-flow blower fan (hereinafter, also simply referred to as blower fan) 9. As a result, the ambient temperature distribution in the heating chambers 5, 6, 7 is made uniform. Note that this example is a soldering device that reflow-solders only the upper surface side of the wiring board 1, and the heater 8 provided below the transport conveyor 2 is provided to supplementally heat the lower surface of the wiring board 1. There is something. 10 is the blower fan 9
It is a drive motor of.

The reflow soldering apparatus shown in FIG. 3 (b) is
A partition plate 11 is provided in the heating chambers 5, 6, 7 to form a circulation path 12 for the atmosphere, and the atmosphere heated by the heater 8 is blown onto the wiring board 1 as hot air to heat the wiring board 1. . In addition, the hot air outlet 13 is provided with a rectifying plate 14 having a large number of through holes 15 in multiple stages (may be one stage) so that the hot air is uniformly blown to the wiring board 1. That is, the atmosphere in the heating chambers 5, 6, 7 is circulated by an axial-flow type blower fan (hereinafter, also simply referred to as a blower fan) 16 for circulation and is blown to the wiring board 1. . This example is also a soldering device for reflow soldering only the upper surface side of the wiring board 1, and the heater 8 provided below the transport conveyor 2 is provided to supplementally heat the lower surface of the wiring board 1. There is something.

By the way, the amount of heat input from the hot air to the wiring board 1 when the hot air hits or is blown on the wiring board 1 increases as the wind speed increases. Therefore, FIG.
The atmosphere blown onto the wiring board 1 not only when the wiring board 1 is heated by hot air as shown in (b) but also when the atmosphere is agitated when infrared rays are heated as shown in FIG. 3 (a). Is required to be uniform.

That is, it is most important to uniformly heat the wiring board 1 and the components mounted on the wiring board 1 in order to obtain good and high-quality solderability.

FIGS. 4 (a) and 4 (b) are views showing the distribution characteristics of the axial flow type fan and its wind speed / air volume. FIG. 4 (a) shows the axial flow type fan seen from the motor mounting side. Front view, Figure 4
4B is a side view of FIG. 4A, and shows the distribution of the wind speed and the air volume by the length of the arrow, that is, the size of the wind speed and the air volume, that is, the length of the arrow. That is, the axial-flow type blower fan 21 has a configuration in which the blades 23 are provided on the base 22.
Is attached to a rotary drive shaft 24 connected to a motor or the like. Therefore, as illustrated in FIG. 4B, in the central portion of the axial-flow type blower fan 21, that is, in the rotary drive shaft 24 portion with the base 22, the wind velocity / volume of the blown air is relatively high as indicated by the arrow. It gets smaller (the arrow is shorter),
Its distribution is non-uniform.

In the example of FIG. 3B, when the main purpose is to circulate the atmosphere, the straightening plate 14 (the straightening plate 14A having a large number of large through holes 15A and the relatively small through holes 15).
The rectifying plate 14B) provided with a large number of Bs is provided.
This is because in consideration of the characteristics of the axial-flow type blower fan 21 as shown in FIG. 4, hot air (air velocity / air volume) is uniformly blown to the wiring board 1. That is, the current plate 14
Due to the pressure loss and the atmospheric flow resistance generated by A and 14B, the through holes 15A and 15 of the straightening plates 14A and 14B are formed.
This is a configuration in which hot air is blown out from B at a uniform wind speed.

On the other hand, when the main purpose is to stir the atmosphere as shown in the example of FIG. 3A, the characteristics of the axial-flow type blower fan 21 of FIG. 4 are taken into consideration so that the stirring is uniform. The configuration is adopted.

FIGS. 5 (a) and 5 (b) are views for explaining an example of the cover for hot air diffusion, and FIG. 5 (a) is a perspective view of the cover for hot air diffusion seen from an oblique lower side, FIG. (B) is a side sectional view showing an example used for a blower fan for stirring. In addition,
This figure is an excerpt from Japanese Utility Model Publication No. 7-26050.

That is, the air is blown to the opening surface 26 of the lattice-like or mesh-like surface of the cover body 25 for hot air diffusion, and the opening surface 26.
This is a technique that eliminates the occurrence of temperature unevenness as hot air in which linear flows are aggregated.

[0015]

However, due to the characteristics of the axial flow type blower fan 21 as described above, the rotation drive shaft 24 thereof is provided.
The wind speed and volume inevitably decrease in the central part where is located. If this is attempted to be solved only by the conventional hot air of the straightening vane 14 and the technology of the cover 25 for diffusion, in order to obtain the hot air of the target wind speed and volume from the hot air outlet, the pressure loss and the flow resistance are increased. On the other hand, it is necessary to increase the size of the blower fan and increase the output of the motor. That is, there was a problem that it was necessary to be prepared for an increase in loss due to air blowing.

Further, in general, a larger blower fan and a higher output of a motor make non-uniform distribution of wind speed and air volume more remarkable, and therefore it is difficult to achieve a fundamental solution even by the above method. There were problems such as.

An object of the present invention is to realize an equalizer for making the airflow velocity and air volume characteristics of an axial flow type fan uniform, so that a reflow soldering apparatus using the axial flow type fan can be used for a wiring board or the like. An object of the present invention is to obtain a reflow soldering device capable of uniformly heating a soldering work and manufacturing a product having excellent solderability and soldering quality.

[0018]

The reflow soldering apparatus of the present invention is characterized by using an equalizer having a cone shape and a large number of through holes on the conical surface. This equalizer is the center of the equalizer. The shaft is aligned with the axis of the rotary drive shaft of the axial-flow fan, and the top side of the equalizer is provided toward the front side in the blowing direction of the axial-flow fan. Further, the through holes are provided so that the opening ratio of the equalizer is larger on the top side than on the hem side.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION In the reflow soldering apparatus of the present invention, an equalizer having a conical shape (conical shape or pyramidal shape) and having a large number of through holes on the conical surface is provided on the blower side of an axial flow type fan. When the equalizer is installed, the center axis of the equalizer is aligned with the axis of the rotary drive shaft of the axial-flow fan, and the top of the equalizer is directed forward in the blowing direction of the axial-fan. It was provided by.

Therefore, when blown by the blower fan, it blows against the equalizer and flows toward the top along the surface of the equalizer and is blown through the through holes. Therefore, the wind speed and the air volume are sent to the shaft center side of the rotary drive shaft with a relatively small wind speed at a sufficient air speed and air volume, and the air speed and air volume of the hot air blown through the through holes of the equalizer are made uniform. . As a result, the work to be soldered can be heated uniformly.

Further, with respect to the hem side of the equalizer,
Opening ratio toward the top (opening area per unit area)
Through holes are formed so that

Therefore, by increasing the aperture ratio on the side of the rotary shaft of the axial-flow type blower fan on the axial center side where the wind speed and air volume are small, that is, on the top side of the equalizer, the hot air blown from each part of the equalizer is increased. The wind speed and the air volume can be made more uniform. As a result, the work to be soldered can be heated more uniformly.

The aperture ratio changes the density distribution of the same pore size,
It can be adjusted by changing the diameter of the through hole. It can also be adjusted by changing the shape of the holes.

[0024]

EXAMPLES Examples of the reflow soldering apparatus according to the present invention will be described below.

(1) Principle Configuration of Equalizer FIGS. 1 (a) to 1 (d) show an embodiment of the present invention and show a mode in which the equalizer is used for an axial flow type fan of a reflow soldering apparatus. FIG. 1A is a side sectional view showing a positional relationship between an axial flow type fan and an equalizer,
A diagram showing the distribution characteristics of the wind speed and the air volume, FIG. 1 (b),
(C) and (d) are perspective views showing various examples of the equalizer, and the same reference numerals as those in FIG. 4 denote the same parts.

That is, an equalizer 31 having a cone shape (conical shape or pyramid shape) and provided with a large number of through holes 32 on the conical surface is provided on the front side of the axial flow type fan 21 in the air blowing direction. When the equalizer 31 is provided, the center line c ₁ of the equalizer 31 is aligned with the axis c ₂ of the rotary drive shaft 24 of the axial flow type blower fan 21, and the top portion 34 of the equalizer 31 is provided.
The side is provided so as to face the front of the axial flow type fan 21 in the air blowing direction.

A greater effect can be obtained by changing the size and shape of the large number of through holes 32 provided in the equalizer 31 so that the opening ratio increases toward the skirt 33 side toward the top 34 side.

In each of the examples shown in FIGS. 1 (b), (c) and (d),
The shape of the through hole 32 is the same, and the size of the through hole 32 is increased to increase the size of the through hole 32 with respect to the hem 33 side of the equalizer 31.
An example is shown in which the aperture ratio is increased toward the 4th side. The example of FIG. 1C has a configuration in which the top 34 is cut along a plane orthogonal to the center line c ₁ so that the cut surface becomes the through hole 35. These FIG. 1 (b),
The configuration of (c) can also be applied to a pyramid-shaped equalizer 31 as shown in FIG. In addition, in FIG. 1 (d),
Since the center line c ₁ and the ridge line of the equalizer 31 overlap with each other, the center line c ₁ is drawn in parallel.

Next, the operation will be described. When blown onto the equalizer 31, the blown air from the axial-flow type blower fan 21 flows along the surface of the equalizer 31 as shown in the direction of arrow A while flowing through each through hole 32 in the direction of arrow B to be blown. Therefore, sufficient air is generated also on the base 22 side of the axial flow type blower fan 21, that is, on the rotary drive shaft 24 side, and the equalizer 31 is provided.
The air blown through is uniformized as shown in the distribution of wind speed and volume indicated by the length of the arrow.

In this case, the blades 2 of the axial flow type blower fan 21
According to the shape of 3 and the size of the base 22,
In accordance with the blowing characteristics (distribution characteristics of the wind speed and the air volume indicated by the length of the arrow in FIG. 4B), the opening ratio of the through holes 32 increases toward the top 34 side of the equalizer 31 (the opening ratio distribution characteristics). By selecting (determining), it becomes possible to make the distribution of wind speed and volume even more uniform. In addition, the top portion 34 of the equalizer 31 shown in FIG.
The wind speed by the equalizer 31 can be changed by changing the side angle θ.
The characteristics of uniformization / uniformization of the air volume change, and the smaller the angle θ, the stronger the collected wind force on the base 22 side of the axial flow type blower fan 21, that is, the rotary drive shaft 24 side. Therefore, the comprehensive characteristic (uniformity / uniformity characteristic) of the equalizer 31 is determined by the angle θ and the aperture ratio distribution characteristic of the through hole 32 on the equalizer 31.

Since the equalizer 31 acts as described above depending on its shape, it hardly depends on the pressure loss and the atmospheric flow resistance unlike the straightening vane 14 used in the example of FIG. 3B. The characteristics of wind speed and volume can be made uniform.

(2) Embodiment of Reflow Soldering Device FIG. 2 is a side sectional view showing an example in which the equalizer of FIG. 1 is used in various reflow soldering devices. FIG. 2 (a) shows a heating atmosphere stirring type device. Diagram showing an example of reflow soldering equipment,
2B and 2C are diagrams showing an example of a circulation type reflow soldering device for blowing a heating atmosphere. 2A is the same as the reflow soldering device of FIG.
2B is an example in which an equalizer 31 is attached to each of the reflow soldering devices of FIG. 3B.
3C is an example in which an equalizer 31 is provided in place of the rectifying plate 14 of FIG. 3B, and the same reference numerals as those in FIGS. 1 and 3 denote the same parts.

That is, as shown in FIG. 2A, by providing the equalizer 31 on the blast side of the axial flow type blast fan 9 for stirring, the atmosphere in the furnace body 4 which is stirred by the blast can be uniformly stirred. Like That is, it becomes possible to heat the wiring board 1 more uniformly than before.
It is possible to obtain uniform solderability and manufacture the wiring board 1 of good quality.

Further, in FIG. 2B, the hot air blown onto the wiring board 1 has a uniform and uniform wind velocity, and the wiring board 1
Can be heated more uniformly than before. Further, as can be seen from the operation of the equalizer 31, the equalizer 31 hardly depends on the pressure loss and the atmospheric flow resistance unlike the conventional straightening plate 14. Therefore, in the circulation type reflow soldering apparatus of FIG. Current plate 14 shown in (b)
It is possible to blow hot air having a uniform and uniform wind speed and volume onto the wiring board 1 without using the. As a result, it is possible to use a motor output that is smaller than the conventional one, and moreover, the wiring board 1 can be heated more uniformly than the conventional one by making the hot air blown onto the wiring board 1 uniform and uniform. Like

Therefore, also in FIGS. 2B and 2C, by providing the equalizer 31 of the present invention, the wiring board can be heated more uniformly than in the conventional case, and uniform solderability can be obtained. As a result, a good quality wiring board can be manufactured.

[0036]

As described above, according to the present invention, there are the following effects corresponding to each claim.

According to the reflow soldering device of the first aspect, the characteristics of the wind speed and the air flow of the axial flow type fan are made uniform.
By making it uniform, it becomes possible to evenly stir the heating atmosphere and evenly spray it onto the work to be soldered, such as a wiring board, and to evenly heat the work to be soldered for solderability and soldering. You will be able to manufacture quality products. Also, there is no need to increase the output of the axial-flow fan or motor more than necessary,
An efficient reflow soldering device can be realized.

According to the reflow soldering apparatus of the second aspect, the distribution of the aperture ratio of the through holes on the equalizer can be adjusted to the wind speed / air volume characteristics of the axial flow type blower fan, and further uniform. The uniformed and uniformed airflow is possible, and the effect of claim 1 can be further improved.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the present invention, and is a diagram showing a mode in which the equalizer of the present invention is used for an axial flow fan of a reflow soldering apparatus, and FIG. 1A is an axial flow fan. FIG. 1B, FIG. 1C, and FIG. 1B are side cross-sectional views showing the positional relationship between the equalizer and the equalizer, and FIGS.
(D) is a perspective view showing various shapes of the equalizer.

2 is a side sectional view showing an example in which the equalizer of FIG. 1 is used in various reflow soldering apparatuses, and FIG. 2A is a view showing an example of a stirring type reflow soldering apparatus;
(B), (c) is a figure which shows the example of a circulation type reflow soldering apparatus.

FIG. 3 is a side sectional view showing an example of a conventional reflow soldering device using an axial flow type fan, and FIG. 3 (a) is a diagram showing an example of a stirring type reflow soldering device; )
FIG. 3 is a diagram showing an example of a circulation type reflow soldering device.

4 is a diagram showing the axial-flow type fan of FIG.
FIG. 4A is a front view of the axial-flow type blower fan as seen from the motor mounting side, FIG. 4B is a side view of FIG. 4A, and a view showing distribution characteristics of the wind speed and the air volume.

FIG. 5 is a view showing an example of a conventional cover body for radiating hot air,
FIG. 5A is a perspective view, and FIG. 5B is a side sectional view showing a usage example thereof.

[Explanation of symbols]

1 wiring board 2 Conveyor 3 heating furnace 4 furnace body 5 Heating room 6 Soaking section heating chamber 7 Reflow part heating room 8 heater 9 Axial-flow fan for stirring 11 partition boards 14 Current plate 16 Axial blower fan for circulation 21 Axial blower 22 base 23 feathers 24 rotary drive shaft 31 Equalizer 32 through holes 33 Hem 34 top 35 through hole

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Claims (2)

(57) [Claims] 1. A reflow for soldering the soldered portion of a workpiece to be soldered, which is previously supplied to a soldered portion of a work to be soldered, is heated and melted by a heating device provided in an axial-flow fan. In the soldering device, a cone-shaped equalizer having a large number of through holes in the conical surface is used, with its central axis aligned with the axis of the rotary drive shaft of the axial-flow fan, and the top side of the equalizer. Provided toward the front side in the blowing direction of the axial flow type blowing fan,
A reflow soldering device characterized in that 2. The reflow soldering device according to claim 1, wherein the through hole is formed so that the opening ratio of the equalizer is larger on the top side than on the hem side.