JPS62148085A - Vapor reflow type soldering device - Google Patents

Abstract

PURPOSE:To reduce the running cost and to improve the safety by providing respectively air curtain device at the inlet and outlet ports of the transfer path of the body to be treated and further by arranging the recover and cooling means of a heating medium on the air curtain device. CONSTITUTION:An air curtain device 15 is respectively arranged at the inlet port of the carry-in side transfer path 2 and the opening part 14 of the outlet port of the carry-out side transfer path 3. the device 15 is composed of a circulating air discharging nozzle 16, suction nozzle 17 and the fan 18 with motor, further, the heating medium cooler 19 which condenses the saturated vapor of the heating medium 11 is arranged at the inner part of the device 19. The air accelerated and pressurized by the fan 18 is spouted from the discharging nozzle 16 to form an air curtain for the opening part 14. Moreover, the heating medium 11 in the circulating air to be liquified with condensation by the cooler 19 is recovered to a vapor tank 1. In this way, the consumption and leakage of expensive heating medium 11 are prevented and the reduction in the running cost and the improvement in safety are enabled.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a vapor reflow soldering device,
Vapor reflow method suitable for soldering printed wiring boards, especially high-density mounted printed wiring boards using semiconductor chip parts such as so-called flat pack elements, resistors, capacitors, etc., in which electrode terminals are taken out in a flat manner in four directions. This invention relates to a soldering device.

[Background of the invention]

In recent years, the high-density mounting of electronic components on printed wiring boards has become more and more advanced, but since the soldering work for bonding electronic components such as semiconductor chips to printed wiring boards is the final process on the line, the quality of the soldering is critical. Because it affects the performance of electronic components, soldering technology has come to be seen as an extremely important technology on the production line.

Recently, due to the need to improve the uniformity of temperature distribution in the furnace where soldering work is carried out and to avoid harmful overheating of electronic components, steam with a high density relative to air has been used as a heat medium and its latent heat of condensation has been utilized. Paper reflow (steam remelting) type soldering equipment, which heats the workpiece using steam, is attracting attention.

This device, as described in Japanese Patent Application Laid-Open No. 60-106502, mounts electronic components on the solder pattern of a printed wiring board, and as described above, this printed wiring board is saturated with a heat medium having a high specific gravity relative to air. The solder is heated and melted by passing it through steam, and the electronic components are soldered onto the printed wiring board. This is a soldering device equipped with a vapor tank called a vapor reflow tank.

The heat transfer medium used in such a steam tank is an inert organic agent, the saturated steam of which has a molecular weight of, for example, about 820 grams per mole under the applied temperature and pressure. Some have about 20 times the specific gravity to air. Such a heat medium is very expensive, and various recovery devices have been devised to recover used steam for reuse.

First, with reference to FIG. 10, a typical conventional horizontal vapor reflow soldering apparatus using a belt conveyor will be described.

FIG. 10 is a configuration diagram of a conventional vapor reflow soldering apparatus.

In FIG. 10, 1 is a steam tank in which a steam generating tank 1a for boiling and heating the heat medium 11 and a furnace tank section for heating and melting the solder of the workpiece are integrated, and 2 is a steam tank for heating the workpiece Reference numeral 3 denotes an inlet-side conveyance path for carrying the soldering members 13 into the steam tank 1, an outlet-side conveyor path for carrying out the processed soldering members 13, and 4 a conveyor for conveying the soldered members 13.

5 is a heater provided at the lower part of the steam tank 1, that is, the steam generation tank 18; 6 is an upper cooling coil provided at the upper part of the steam tank 1; The side cooling coil 8 is a carry-out side cooling coil provided on the outer periphery of the carry-out conveyance path 3, 9 is a carry-in side exhaust port, and 10 is a carry-out side exhaust port.

The operation of the vapor reflow soldering apparatus configured as described above will be explained.

The saturated steam 12 of the heat medium that is boiled and evaporated by the heater 5 immersed in the heat medium 11 stored in the lower part of the steam tank 1', that is, the steam generation tank 1a, rises to the upper part of the steam tank 1, and its height is equal to that of the upper part. It is controlled by the condensing action of the cooling coil 6.

The saturated steam 12 that has flowed into the carry-in side conveyance path 2 and the carry-out side conveyance path 3 is cooled by the carry-in side cooling coil 7 and the carry-out side cooling coil 8, and the amount of steam is gradually reduced. A small amount of remaining steam is exhausted to the atmosphere from the carry-in side exhaust port 9 and the carry-out side exhaust port IO.

On the other hand, the workpiece to be soldered electronic components to a printed wiring board, that is, the soldering member 13, is carried by the conveyor 4 into the carry-in conveyance path 2, is brought into contact with the saturated steam 12, is gradually heated, and is heated in a steam tank. 1 goes inside, saturated steam 1
The solder is heated and melted by the condensation latent heat of step 2, and the components are soldered together.

At this time, a part of the saturated steam 12 condenses and liquefies and falls.
It accumulates in the lower part of the steam tank 1, that is, in the lower part of the steam generation tank.

The soldered members 13 that have been processed are transferred to the unloading conveyance path 3.
It is gradually cooled down and removed from the equipment.

In such a vapor reflow soldering apparatus, the following problems occur.

1) The conveyor 4 passes through the entrance and exit of the conveyance path, and an opening is absolutely necessary in order to allow the soldering member 13, which is the object to be processed, to enter and exit. For this reason, the saturated steam 12 of the heating medium leaks into the atmosphere from the opening.

Heat carriers are generally extremely expensive, so leakage of saturated steam will increase running costs, and the heat carrier may contain toxic and corrosive gases, albeit in small amounts, which poses safety concerns. It becomes a problem.

2) In order to prevent the saturated steam 12 of the heating medium from leaking into the atmosphere, an exhaust port may be provided on the wall near the opening for exhaust. However, if the exhaust volume at the exhaust port is small, saturated steam will leak from the opening, and if the exhaust volume is large, excess saturated steam will be discharged. On the other hand, the amount of electricity for the heater 5 increases, which raises the manufacturing price and running cost of the device.

[Purpose of the invention]

The present invention was made in order to solve the problems of the prior art described above, and it minimizes the leakage of saturated steam as a heating medium, improves the recovery of the heating medium, and reduces the consumption of expensive heating medium. The purpose is to provide a vapor reflow soldering device that has low running costs and high safety.

[Summary of the invention]

The configuration of the vapor reflow soldering apparatus according to the present invention includes a steam tank in which saturated steam as a heating medium is brought into contact with the workpiece to heat and melt the solder on the workpiece, and a soldering process is carried out by heating and melting the solder on the workpiece. In a steam-heating soldering apparatus equipped with a conveyance path for carrying in and out a processing material, an opening serving as an entrance and exit of the conveyance path is provided with saturated steam of a heat medium flowing from the steam tank to the conveyance path. Equipped with an air curtain device to block leakage, this air curtain device is equipped with
It is equipped with a heat medium recovery cooling means for condensing the saturated vapor of the heat medium mixed in the circulating air flow of the air curtain.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 9.

First, FIG. 1 is a configuration diagram of a vapor reflow soldering apparatus according to an embodiment of the present invention, and FIG.
-A is a cross-sectional view taken along the arrow A, and in the figure, the same reference numerals as in FIG. 10 are the same parts as in the prior art, so the explanation thereof will be omitted.

In the embodiment shown in FIGS. 1 and 2, an air curtain device 1 for blocking leakage of saturated steam is installed at the entrance/exit opening 14 of the conveyance path.
5 is an explanation of an example of a basic aspect equipped with the following.

Details of the air curtain device 15 are shown in FIG.

In FIG. 2, 16 is a discharge nozzle that blows out a circulating air flow forming an air curtain; 17 is a suction nozzle that sucks in the air flow; 18 is a motorized fan that generates a circulating air flow; 19 is an air curtain. A heat medium cooler 20 is a heat medium reservoir for recovering the condensed and liquefied heat medium, and 20 is a heat medium reservoir for recovering the condensed and liquefied heat medium. The cooler 19 and the heat medium reservoir 20 are located at the lower part of the air curtain device so that the heat medium can be easily recovered.

21 is a motorized fan 18 installation part and a discharge nozzle 16
The duct 22 is a duct for air circulation that communicates the suction nozzle 17 and the heat medium cooler 19 installation part.

Further, 32 indicates a return pipe connecting the heat medium reservoir 20 and the steam generation tank 1a.

The functions of the vapor reflow soldering apparatus configured as described above, particularly the air curtain device 15 and the heat medium recovery cooling means, will be explained.

The air accelerated and pressurized by the motorized fan 18 is
As shown by the arrow in the figure, the air passes through the duct 21 and reaches the discharge nozzle 16, where it is further rectified and accelerated and flows in front of the opening 14 to form an air curtain.

By this air curtain, the saturated steam 12 of the heating medium flowing from the evaporation tank 1 to the opening 14 of the conveyance path (input side conveyance path 2 in the figure) is blocked from leaking into the outside air from the opening 14, and a part of it is blocked from leaking into the outside air. The saturated steam of the air mixes into the circulating air stream of the air curtain.

The air containing the saturated vapor of the heat medium sucked into the suction nozzle 17 passes through the duct 22 and is guided to the heat medium cooler 19 where it is cooled, and is again accelerated and pressurized by the motorized fan 18 to repeat the circulation. .

When the heat medium is cooled by the heat medium cooler 19, the saturated vapor of the heat medium contained in the air is condensed and liquefied and accumulated in the heat medium reservoir 20. The amount of the liquefied heat medium accumulated in the heat medium reservoir 20 is appropriately monitored, and when it has accumulated to a certain extent, it is recovered to the heat medium storage section of the steam generation tank 1a via the return pipe 32.

Although the air curtain device at the opening 14 of the carry-in conveyance path 2 has been described in FIG. 2, the same applies to the opening of the carry-out conveyance path 3 side.

According to this embodiment, the following effects are achieved.

1) Since the air curtain covers the entire opening, there is very little contact between the internal atmosphere of the soldering equipment and the atmosphere.
This has the effect of blocking leakage of saturated steam as a heat medium.

2) A small amount of saturated vapor of the heat medium that is carried in the air flow of the air curtain is recovered by the heat medium cooler 19. Therefore, the leakage of the heat medium into the atmosphere is extremely small, the consumption of the expensive heat medium is small, and running costs can be reduced.

Furthermore, safety is ensured because the leakage of saturated steam of the heating medium into the atmosphere is extremely small.

3) By appropriately controlling the temperature of the air curtain, it is possible to accelerate or adjust the preheating and cooling of the soldering components, which has the secondary effect of reducing thermal problems of the soldering components.

4) Since the amount of air in the air curtain is balanced independently on the carry-in side and the carry-out side, air does not enter into the soldering equipment such as the conveyance path or the steam tank 1, which disturbs the flow of the saturated steam 12. Very rarely.

Next, another embodiment of the present invention will be described with reference to FIGS. 3 and 4.

Here, FIG. 3 is a schematic configuration diagram of an air curtain device attachment part of a pH reflow soldering apparatus according to another embodiment of the present invention, and FIG. 4 is a sectional view taken along the line B-B in FIG. 3. In the figure, the same reference numerals as in FIGS. 1 and 2 are the same parts as in the previous embodiment, so the explanation thereof will be omitted.

In the embodiments shown in FIGS. 3 and 4, the air curtain device shown in FIGS. 1 and 2 is provided with a shutter device that opens and closes by detecting the presence or absence of an object to be processed.

As shown in FIG. 4, this shutter device includes a shutter plate 23, a baffle plate 24, and which shutter plate 23.
, and an opening/closing drive rod 25 that opens and closes the baffle plate 24.

Inside the shutter plate 23, that is, on the surface on the conveyance path side,
In order to improve the sealing performance between the shutter plate 23 and the opening 14, an inner lining 29 made of rubber or the like is formed.

The operation of this shutter device will be explained.

The soldering member 13 related to the workpiece is transferred to the carry-in conveyance path 2.
A controller (not shown) receives the signal sent to the controller and sends a signal to an opening/closing drive system (not shown) according to the sequence.

The mechanism of the opening/closing drive system is a known and common one, so it will not be particularly illustrated or explained here.

The opening/closing drive system that received the signal is operated by the opening/closing drive rod 25.
Move to open the shutter plate 23. At this time, confirmation is made by receiving a signal from a sensor (not shown) that the shutter is open.

If there is no signal indicating that the shutter plate 23 is open, the conveyor 4 is stopped to avoid collision between the shutter plate 23 and the soldering member 13.

When the shutter plates 23 on the carry-in side and the carry-out side are opened, the soldering members carried in are heated with saturated steam of the heating medium and a predetermined soldering operation is performed.

In response to an instruction from the controller that has received a signal that the final soldering member 13 has been carried out from the carry-out conveyance path 3, the carry-in side
Each shutter plate 23 on the unloading side is closed.

When the shutter plate 23 closes, the baffle plate 2
4 closes the upper half of the discharge nozzle 16 and the suction nozzle 17, and an air curtain is formed around the gap 28 with the conveyor 4 in between.

In order not to disturb the flow of the air curtain at this time, partition plates 26.2 and 26.
7 is provided.

According to the embodiment shown in FIGS. 3 and 4, the same effects as those described in the above-mentioned embodiment shown in FIGS. 1 and 2 can be expected, as well as the following effects.

1) When there is no soldering member 13 on the conveyor 4 or when the height of the soldering member 13 is low, such as when starting and stopping the soldering device, the shutter plate 23 closes to narrow the opening 14. Therefore, the amount of saturated steam of the heat medium carried by the air curtain decreases, and the amount of cooling water in the heat medium cooler 19 for recovering the heat medium is accordingly reduced, and the air curtain also reduces the circulating air flow in a narrow range. Therefore, the electric power of the motorized fan 18 can also be reduced, further reducing running costs and improving safety.

2) Since the opening is variable, it is easy to adapt to the height of the soldering member 13.

3) By changing the width (height direction) of the shutter plate 23 in accordance with the height of the soldering member 13, the area of the opening where the internal atmosphere of the soldering apparatus and the atmosphere come into contact can be minimized.

4) By changing the dimensions of the shutter plate 23 or replacing the shutter plate, the gap between the opening and the soldering member 13 can always be minimized, so the dimensions of the conveyance path can be set large and the gap can be greatly improved. It is possible to accommodate soldering members 13 having different dimensions.

Next, still another embodiment of the present invention will be described with reference to FIGS. 5 and 6.

Here, FIG. 5 is a schematic configuration diagram of an air curtain device mounting portion of a vapor reflow soldering device according to still another embodiment of the present invention, and FIG. 6 is a cross section taken along the line C-C in FIG. In the figure, parts with the same reference numerals as those in FIGS. 3 and 4 are equivalent parts, so a description thereof will be omitted.

The embodiment shown in FIGS. 5 and 6 is an example in which a cooling means is provided on the inner surface of the shutter plate as described in the embodiment shown in FIGS. 3 and 4.

In this shutter device, as shown in FIGS. 5 and 6, a shutter cooler 30 is attached to the inner surface of the shutter plate 23A, that is, the surface of the shutter on the conveyance path side.

With this configuration, the same actions and effects as those explained in the embodiments shown in FIGS. 3 and 4 are expected, and in addition to the
The saturated steam of the heating medium flowing inside reaches the vicinity of the opening 14 and is condensed by the shutter cooler 30, so the amount of steam mixed into the circulating air flow of the air curtain centered around the gap 28 is reduced, and the heat transfer is reduced. This also has the effect of reducing leakage of the medium into the atmosphere.

5 and 6 are examples of the shutter device in the air curtain device on the carry-in side, but since the shutter device on the carry-out side is also completely the same, the explanation will be omitted.

Next, still another embodiment of the present invention will be described with reference to FIGS. 7 and 8.

Here, FIG. 7 is a schematic configuration diagram of an air curtain device mounting portion of a vapor reflow soldering device according to still another embodiment of the present invention, and FIG. 8 is a cross section taken along the line D-D in FIG. 7. 3. In the figure, the same reference numerals as in FIG. 3.4 are the same parts, so the explanation thereof will be omitted.

The embodiment shown in FIGS. 7 and 8 is an example in which cooling fins are provided on the outer surface of the shutter plate as described in the embodiment shown in FIGS. 3 and 4.

In this shutter device, as shown in FIGS. 7 and 8, cooling fins 31 are provided on the outer surface of the shutter plate 23B, that is, on the air circulation side surface of the air curtain of the shutter.

In this embodiment, the baffle plate 24 shown in FIGS.
, with the partition plates 26 and 27 removed.

With this configuration, the same functions and effects as those explained in the embodiment of Fig. 3.4 can be expected, and since the shutter plate 23B is cooled by the circulating air flow of the air curtain, The saturated steam of the heat medium flowing inside the heat transfer medium 2 is condensed near the opening 14 by the shutter plate 23B.

Therefore, the amount of steam mixed into the circulating air flow of the air curtain centered around the gap 28 is reduced, and the leakage of the heat medium to the atmosphere is also reduced.

Note that although FIGS. 7 and 8 show examples of shutter devices in the air curtain device on the carry-in side, the explanation will be omitted since the shutter device on the carry-out side is also completely the same.

Next, still another embodiment of the present invention will be described with reference to FIG.

FIG. 9 is a configuration diagram of a vapor reflow soldering apparatus according to still another embodiment of the present invention.
Since the parts with the same reference numerals as those in the figures are equivalent to those in the embodiment of FIG. 1, their explanations will be omitted.

The difference between the embodiment shown in FIG. 9 and the embodiment shown in FIG. The reason is that it is sloped downhill.

With this configuration, the same effects as those of the embodiments shown in FIGS. 1 and 2 can be expected, and the liquefied heat medium condensed in the conveyance path can be prevented from flowing through the lower walls 2'a and 3'a of the conveyance path. The heat medium flows down along the slope of the steam generating tank 1a, and recovery to the heat medium storage section of the steam generation tank 1a is promoted.

〔Effect of the invention〕

As described above, according to the present invention, the leakage of saturated steam of the heat medium is minimized, and the recovery of the heat medium is improved to reduce consumption of the expensive heat medium. A vapor reflow soldering device with low running costs and high safety can be provided.

[Brief Description of the Drawings] Fig. 1 is a configuration diagram of a vapor reflow soldering apparatus according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the line A-A in Fig. 1, and Fig. 3 1 is a schematic configuration diagram of an air curtain device mounting portion of a vapor reflow soldering device according to another embodiment of the present invention; FIG. 4 is a sectional view taken along the line B-B in FIG. 3;
5 and 7 are both schematic configuration diagrams of an air curtain device mounting part of a paper IJ flow set soldering apparatus according to still another embodiment of the present invention, and FIG. -C
8 is a sectional view taken along the line D-D in FIG. 7, FIG. 9 is a configuration diagram of a vapor reflow soldering apparatus according to still another embodiment of the present invention, and FIG. 1 is a configuration diagram of a conventional vapor reflow soldering device. 1... Steam tank, 1a... Steam generation tank, 2, 21...
- Input side conveyance path, 3, 3'... Output side conveyance path, 2'a
, 3'a... Lower wall, 4... Conveyor, 5... Heater, 11... Heat medium, 12... Saturated steam, 13
...Soldering member, 14...Opening, 15...
Air curtain device, 16...Discharge nozzle, 17...
Suction nozzle, 18... Fan with electric motor, 19...
・Heat medium cooler, 20...Heat medium reservoir, 21.22・
...Duct, 23, 23A. 23B...shutter board, 24...evil IJl board, 2
5... Opening/closing drive rod, 30... Shutter cooler, 31... Trz: 2nd E Q 4th Figure 5 Figure 7 Figure 89 Page 9

Claims (1)

[Claims] 1. A steam tank in which soldering is performed by bringing the saturated steam of a heating medium into contact with the workpiece to heat and melt the solder on the workpiece, and carrying the workpiece into and out of this steam tank. In a vapor reflow soldering apparatus, a vapor reflow soldering apparatus is provided with an opening serving as an inlet/outlet of the transport path for blocking leakage of saturated steam of the heat medium flowing from the steam tank to the transport path. A vapor reflow soldering device comprising an air curtain device and a heat medium recovery cooling means for condensing the saturated vapor of the heat medium mixed in the circulating air flow of the air curtain. . 2. The vapor reflow soldering apparatus according to claim 1, wherein the conveying path has a lower wall inclined downwardly toward the steam tank. 3. The vapor reflow solder according to claim 1, which is provided with a shutter device that detects the presence or absence of the object to be processed and opens and closes it at the opening of the conveyance path equipped with an air curtain device. attaching device. 4. The vapor reflow soldering apparatus according to claim 3, wherein the shutter device is provided with a cooling means on the conveying path side surface of the shutter plate. 5. The vapor reflow soldering device according to claim 3, wherein the shutter device is provided with cooling fins on the air circulation side surface of the air curtain on the shutter plate.