JP2000059020A - Single-sided reflow furnace cooling device for soldering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single-sided reflow furnace cooling device for soldering of a structure, wherein cooling air is sent to the side of a component mounting surface on the upper surface of a printed board, while the lower surface of the board is heated extending over the whole lower surface in a reflow furnace, the cooling air is fed to the board stably and uniformly, and a control of the amount of the cooling air can be easily executed. SOLUTION: In a single-sided reflow furnace cooling device for soldering of a structure, wherein shielding plates 8a and 8b are provided on a printed board 10, an aperture 9 for cooling air passage is formed in the shielding plates along the carrying direction of the board, air supply fans 6 for sending a cooling air in the side of the board are provided on the sidewall 15a, which is positioned on the side still higher than the shielding plates, of a reflow furnace, and deflecting plates 7 for guiding the cooling air, which is sent from the air supply fans, toward the direction of the aperture formed in the shielding plates are provided, a plurality of the air supply fans 6 are provided along the carrying direction of the board and a plurality of the deflecting plates 7 are provided in such a way that the plates 7 are made to juxtapose to each other at intervals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cooling device for a single-sided reflow furnace for soldering. More particularly, the present invention relates to a cooling device for a single-sided reflow furnace that blows hot air from a lower surface of a substrate to cool a component mounting surface on an upper surface of the substrate during solder melting.

[0002]

2. Description of the Related Art As a method for soldering electronic components and the like on a printed circuit board, a spot type reflow soldering method is known. This spot-type reflow soldering method uses a reflow furnace that injects hot air. The connection terminals of electronic components mounted on a printed circuit board are projected to the lower surface of the substrate, and the connection terminals are applied to the lower surface of the substrate. The cream solder is melted and soldered by hot air blown from hot air spray nozzles disposed at positions corresponding to the respective solders.

However, in such a spot-type reflow soldering method, since nozzles are provided corresponding to the positions of connection terminals of each component, the nozzles provided on the nozzle panel each time the circuit of the printed circuit board is different and the component arrangement is different. The position has to be changed, which is troublesome. In addition, since each nozzle blows hot air to each connection terminal in the vicinity of the connection terminal, molten solder may drop into the hole of the nozzle and become clogged, making inspection and maintenance troublesome.

Therefore, the present inventors have improved the drawbacks of the spot-type reflow soldering method and supplied hot air to the entire lower surface of the printed circuit board from which the connection terminals of the non-heat-resistant electronic parts protrude. A single-sided reflow furnace has been developed that cools each component while controlling the volume of the cooling air by introducing cooling air to the upper surface of the substrate on which the components are mounted and adjusting the amount of the cooling air.

FIGS. 2A and 2B show an example of the configuration of a soldering apparatus using a single-sided reflow furnace proposed by the present inventors. FIG. 2A is a schematic configuration diagram of the whole, and FIG. FIG. 2C is a cross-sectional view of a portion, and FIG. 2C is a side view of a cooling device portion of the reflow furnace.

As shown in FIG. 1A, a reflow soldering apparatus 1 is provided with a preheat section 3, a reflow section 4, and a cooling section 5 along a conveyance path 2 of a printed circuit board (not shown). . The preheating unit 3 includes first, second, and third preheaters 3a, 3b, and 3c, and preheats a printed circuit board to a predetermined temperature in order. Reflow part 4
Is a part constituting a reflow furnace for actually blowing hot air onto a printed circuit board and soldering the same, as described later. The printed circuit board soldered in the reflow furnace has a cooling unit 5
Then, cooling is performed from both upper and lower surfaces by a cooling fan (not shown).

In the reflow section 4 of such a reflow soldering apparatus 1, as shown in FIG. 1B, the printed circuit board 10 is transported in the transport direction (vertical direction in the drawing), and hot air 13 is not shown on the lower surface side. It is sprayed from the nozzle.
Electronic components 11 are mounted on the printed circuit board 10, and connection terminals 12 thereof protrude from the lower surface of the printed circuit board 10. The portion of the printed circuit board 1 where the connection terminals 12 protrude
The cream solder is applied to the lower surface side of 0 in the previous step. This cream solder is melted by the hot air 13 of the reflow furnace, and the connection terminals 12 are soldered.

A pair of shielding plates 8a and 8b made of heat-resistant glass are provided in a casing 15 above the printed board 10. An opening 9 for introducing cooling air is formed between the shielding plates 8a and 8b along the transport direction of the printed circuit board 10. The width of the opening 9 can be adjusted by a motor (not shown). The width of this opening is
Adjustment is made so as to obtain an optimum cooling air flow according to the type of the electronic component 11 and the heat generation amount.

An air supply fan 6 is provided on a side wall 15a of the casing 15 above the shielding plates 8a and 8b, and a deflecting plate 7 is provided in the casing 15. The air supply fan 6 is for sucking outside air and sending it into the casing as cooling air for cooling the printed circuit board 10. The deflecting plate 7 uses the supplied air (outside air) for shielding plates 8a and 8b. It is for guiding toward the opening 9 between them. After passing through the upper surface of the printed circuit board 10, the cooling air is discharged from both sides to the outside by an exhaust duct (not shown).

[0010] The reflow section 4 is connected to the printed circuit board 1.
0, the entire lower surface of the printed circuit board 10 is entirely heated by the hot air 13 and the upper surface side of the printed circuit board 10 is cooled. Can withstand the amount of heat of the hot air blown to the surface.

Such an air supply fan 6 and a deflection plate 7
As shown in (C), one deflecting plate 7 and one air supply fan 6 are provided substantially at the center of the deflecting plate 7 along the printed board conveyance direction P.

[0012]

However, in the cooling structure of the reflow furnace having the structure shown in FIG. 2, only one air supply fan and one deflection plate are provided along the printed board conveying direction above the reflow furnace. Since the cooling air is not provided, the cooling air is disturbed and is not uniformly supplied to the upper surface of the printed circuit board, so that stable cooling cannot be performed. Also, since the cooling strength is adjusted only by adjusting the opening width of the shielding plate, it is not easy to adjust the cooling amount corresponding to the amount of heat generated by the electronic components on the printed circuit board, and the structure becomes complicated. In some cases, an optimum cooling air volume could not be obtained.

The present invention has been made in consideration of the above-mentioned points, and is directed to a cooling apparatus for a single-sided reflow furnace which sends cooling air to a component mounting surface on the upper surface of the printed circuit board while heating the entire lower surface thereof in the reflow furnace. An object of the present invention is to provide a cooling device for a single-sided reflow furnace for soldering, which stably and uniformly supplies cooling air to a printed circuit board and can easily adjust the amount of cooling air.

[0014]

In order to achieve the above object, according to the present invention, a component to be soldered is mounted on an upper surface of a substrate, and hot air is blown from the lower surface of the substrate to reflow the component. A cooling device for a furnace, wherein a shielding plate is provided above the substrate, an opening for passing cooling air is formed in the shielding plate along a transport direction of the substrate, and a side wall of the reflow furnace above the shielding plate. A single-sided reflow furnace for soldering, comprising: an air supply fan for sending cooling air to the substrate side; and a deflection plate for guiding the cooling air sent from the air supply fan toward the opening direction of the shielding plate. In the cooling device of the present invention, a single-sided reflow furnace for soldering, wherein a plurality of the air supply fans are provided along a direction in which the substrate is conveyed, and a plurality of the deflection plates are provided in parallel at intervals. Provide a cooling device.

According to this configuration, the cooling air sent from the plurality of air supply fans arranged along the direction of transport of the printed circuit board is directed to the opening direction for passing the cooling air by the plurality of deflecting plates arranged in parallel. Therefore, the cooling air is stably and uniformly supplied onto the printed circuit board without being disturbed, and a stable cooling action can be obtained.

In a preferred embodiment, an inverter for controlling the rotation speed of the air supply fan is provided.

According to this configuration, since the rotation speed of the air supply fan is controlled by the inverter, fine adjustment can be performed over 0 to 50 Hz or 0 to 60 Hz according to the power supply frequency, and the air volume can be easily adjusted over a wide range. be able to.

In a further preferred configuration, the opening width of the shielding plate is adjustable.

According to this configuration, the amount of cooling air introduced into the printed circuit board side can be adjusted by adjusting the opening width of the shielding plate. Further, appropriate cooling can be efficiently performed according to the conditions.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram illustrating the configuration of a reflow soldering apparatus according to an embodiment of the present invention.
1 is a schematic configuration diagram of the whole, (B) is a sectional view of a reflow furnace part, and (C) is a side view of a cooling device part of the reflow furnace.

The configuration of the soldering apparatus is different from that of FIG. 2 in the cooling structure of the reflow furnace, and the other basic configuration is the same as that of FIG. That is,
As shown in (A), this reflow soldering apparatus 1
A preheating unit 3, a reflow unit 4, and a cooling unit 5 are provided along a conveyance path 2 of a printed circuit board (not shown). The preheating unit 3 includes first, second, and third preheaters 3a, 3b, and 3c, and preheats a printed circuit board to a predetermined temperature in order. The reflow unit 4 is a part of a reflow furnace that actually blows hot air onto a printed circuit board to perform soldering, as described later. The printed circuit board soldered in the reflow furnace is cooled from both upper and lower surfaces by a cooling fan (not shown) in the cooling unit 5.

In the reflow section 4 of the reflow soldering apparatus 1, the printed board 10 is transported in the transport direction (vertical direction in the figure) as shown in FIG. It is sprayed from the nozzle.
Electronic components 11 are mounted on the printed circuit board 10, and connection terminals 12 thereof protrude from the lower surface of the printed circuit board 10. The portion of the printed circuit board 1 where the connection terminals 12 protrude
The cream solder is applied to the lower surface side of 0 in the previous step. This cream solder is melted by the hot air 13 of the reflow furnace, and the connection terminals 12 are soldered.

A pair of shielding plates 8a and 8b made of heat-resistant glass are provided in a casing 15 above the printed board 10. An opening 9 for introducing cooling air is formed between the shielding plates 8a and 8b along the transport direction of the printed circuit board 10. The width of the opening 9 can be adjusted by a motor (not shown). The width of this opening is
Adjustment is made so as to obtain an optimum cooling air flow according to the type of the electronic component 11 and the heat generation amount.

An air supply fan 6 is provided on a side wall 15a of the casing 15 above the shielding plates 8a and 8b, and a deflection plate 7 is provided in the casing 15. The air supply fan 6 is for sucking outside air and sending it into the casing as cooling air for cooling the printed circuit board 10. The deflecting plate 7 uses the supplied air (outside air) for shielding plates 8a and 8b. It is for guiding toward the opening 9 between them. After passing through the upper surface of the printed circuit board 10, the cooling air is discharged from both sides to the outside by an exhaust duct (not shown).

In this embodiment, as shown in FIG. 3B, three deflection plates 7 are provided in parallel at an interval. Further, as shown in (A) and (C), two air supply fans 6 are provided in parallel along the transport direction P of the printed circuit board. In this way, the outside air is supplied by the two air supply fans 6, and the outside air is supplied through the three deflection plates 7.
By guiding the cooling air to the opening 9 between the holes a and 8b, the cooling air is supplied stably and uniformly onto the printed circuit board without being disturbed, and a stable cooling action is obtained.

Each air supply fan 6 is connected to an inverter 16, which controls the rotation speed. By controlling the number of rotations of the air supply fan by the inverter in this manner, fine adjustment can be performed over 0 to 50 Hz or 0 to 60 Hz according to the power supply frequency, and the air volume can be easily adjusted over a wide range.

FIG. 3 is a simulation model of the cooling structure of the reflow furnace before improvement according to the present invention.
4 is a model for simulation of the improved reflow furnace cooling structure according to the present invention. As shown in FIG. 3, before the improvement, one air supply fan 6 is provided on the side wall 15a of the casing 15, and the external air supplied by the air supply fan 6 is supplied to the opening 9 between the shielding plates 8a and 8b. One deflecting plate 7 for guiding is provided.

On the other hand, in the improved present invention, as shown in FIG. 4, two air supply fans 6 are provided in parallel on the side wall 15a of the casing 15 and supplied by these air supply fans 6. The opening 9 between the shielding plates 8a and 8b
Are provided in parallel at intervals.

FIG. 5 shows the simulation results of the airflow using the models of the cooling structure of the reflow furnace before and after the improvement. (A) shows the configuration before the improvement by the model of FIG. 3, and (B) shows the configuration of the present invention after the improvement by the model of FIG. As can be seen, the air supply fan 1
In (A) before the improvement of the table and one deflection plate, the air flow was
In contrast, a stable streamline toward the opening 9 is formed without disturbance in the airflow in the improved (B) with two air supply fans and three deflection plates, whereas a stable streamline toward the opening 9 is not formed. .

In the present invention, the number of air supply fans is not limited to two, but may be more. Also, the number of deflection plates is not limited to three, but may be any number as long as it is plural. The shape of the deflecting plate is not limited to a rectangular cross section, but may be any curved shape or any other suitable shape for guiding airflow. The position where the deflection plate is attached is not limited to the position shown in the figure, but may be provided at an appropriate position so as to guide the outside air from the air supply fan to the opening of the shielding plate.

[0031]

As described above, in the present invention, the cooling air sent from the plurality of air supply fans arranged along the direction of transport of the printed circuit board is controlled by the plurality of parallelly arranged deflection plates. Since the cooling air is guided in the opening direction for passing the cooling air, the cooling air is stably and uniformly supplied onto the printed circuit board without being disturbed, and a stable cooling action can be obtained.

According to the configuration having the inverter for controlling the rotation speed of the air supply fan, the rotation speed of the air supply fan is controlled by the inverter. Fine adjustment can be performed over a range of up to 60 Hz, and the air volume can be easily adjusted over a wide range.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of a reflow soldering apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration explanatory view of a reflow soldering apparatus before improvement according to the present invention.

FIG. 3 is a perspective view of a cooling structure model before improvement according to the present invention.

FIG. 4 is a perspective view of a cooling structure model according to the present invention.

FIG. 5 is a diagram showing simulation results of airflow distribution before and after improvement according to the present invention.

[Explanation of symbols]

1: soldering device, 2: transport path, 3: preheating section
4: reflow section, 5: cooling section, 6: air supply fan, 7: deflection plate, 8a, 8b: shielding plate, 9: opening, 10: printed circuit board, 11: electronic component, 12: connection terminal, 13: hot air ,
15: Casing, 15a: Side wall.

Claims (3)

[Claims] 1. A reflow furnace cooling device for mounting a component to be soldered on an upper surface of a substrate and blowing hot air from a lower surface side of the substrate to solder the component, wherein a shielding plate is provided above the substrate. An opening for passing cooling air in the shield plate along the direction of transport of the substrate, and an air supply fan for sending cooling air to the substrate side on a side wall of the reflow furnace above the shield plate. A cooling device for a single-sided reflow furnace for soldering, comprising: a deflection plate for guiding cooling air sent from the air supply fan toward an opening direction of the shielding plate. A plurality of the deflection plates are arranged in parallel with a space therebetween, and a single-sided reflow furnace for soldering is provided. 2. The cooling device for a single-sided reflow furnace for soldering according to claim 1, further comprising an inverter for controlling the rotation speed of the air supply fan. 3. The cooling device for a single-sided reflow furnace for soldering according to claim 1, wherein an opening width of the shielding plate is adjustable.