JPH0677812B2 - Vapor flow soldering equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vapor reflow soldering device used for soldering a high-density mounted printed wiring board or the like, and particularly to heat accumulated in the bottom of a steam generation tank. The present invention relates to a vapor reflow soldering apparatus suitable for effectively treating the flux contained in a medium.

[Conventional technology]

In recent years, high-density mounting of electronic components on a printed wiring board is progressing more and more. Soldering is the most important technology in the production line because the quality of the product depends on the quality of the soldering because the final step of the production line is soldering.

Therefore, in recent years, a vapor reflow soldering device that uses the latent heat of condensation of vapor of a heat medium has attracted attention because it is necessary to improve the uniformity of temperature distribution in the furnace and to avoid harmful overheating of parts. FIG. 4 shows a typical vapor reflow soldering device.

FIG. 4 is a system diagram of a conventional vapor reflow soldering device.

The vapor reflow soldering device shown in FIG. 4 includes a preheating chamber 2, a reflow chamber 1, a cooling chamber 3, a conveyor 16 for carrying a soldering member 17 which is an object to be processed, an exhaust gas recovery device 24, And a filtering device 30.

The preheating chamber 2 is provided with a preheating upper heater 14 and a preheating lower heater 15.

The reflow chamber 1 includes a steam generation tank 4 and a soldering member.
It has a carry-in side transport path 5 of 17, a carry-out side transport path 6 of the same soldering member 17, a carry-in side cooler, and a carry-out side cooler. A heater 7 is provided in the steam generation tank 4,
Generate the saturated steam 13 of the heat medium 12, contact the saturated steam 13 of the heat medium 12 to the soldering member 17 that is conveyed,
The solder of the soldering member 17 is heated and melted for soldering. The carry-in side transport path 5 and the carry-out side transport path 6 communicate with the inside of the steam generation tank 4. Further, the carry-in side transport path 5 is provided with a carry-in side exhaust port 10, and the carry-out side transport path 6 is provided with a carry-out side exhaust port 11. The carry-in side cooler is provided with a carry-in side cooling coil 8, and the carry-out side cooler is provided with a carry-out side cooling coil 9. The inlet-side cooler and the outlet-side cooler return the heat medium 12 to the bottom of the steam generation tank 4 through the return pipe 18.

A cooling fan 19 is provided in the cooling chamber 3 so as to cool the soldering member which is a product conveyed to the carry-out side conveying path 6.

The conveyor 16 is composed of a drive sprocket wheel 20, driven sprocket wheels 21 and 22, and a conveyor belt such as a mesh hung between these sprocket wheels 20, 21 and 22. One driven sprocket wheel 21 is arranged outside the preheating chamber 2 which is the loading side of the soldering member 17, and the other driven sprocket wheel 22 is
It is installed outside the cooling room 3, which is the product delivery side,
The conveyor 16 is adapted to carry the soldering member 17 placed on the conveyor belt into the steam generation tank 4 from the carry-in side transport path 5 and then carry out the product from the carry-out side transport path 6 to the outside. .

Inside the exhaust recovery device 24, an exhaust cooling coil 25,
It has a demitasse 26 and a water separator 27, and has a chiller 29 on the outside.
And a pump 28 are installed. This exhaust recovery system 24
From the carrying-in side exhaust port 10 and the exhaust side exhaust port 11,
The exhaust of the heat medium 12 is introduced through the exhaust pipe 23. Cold water is passed through the chiller 29 to the exhaust cooling coil 25. The exhaust cooling coil 25 cools the exhaust of the heat medium 12 and liquefies it. The water separator 27 uses the difference in specific gravity to generate the heat medium 12
It is designed to separate water from water. The Demitas 26
Is configured to collect a part of the exhaust of the heat medium 12 which has not been liquefied by the exhaust recovery device 24. The pumpton
28 is the heat medium 12 after water is separated by the water separator 27.
Is returned to the carry-out side cooler having the carry-out side cooling coil 9.

The filtering device 30 includes a filtering tank 31.
And a cooling coil 32 provided inside thereof, a pump 33 provided outside the filtering tank 31, and a filter 34. The heat medium 12 is transferred from the bottom of the steam generation tank 4 to the filtering tank 31. Cold water is passed from the outside to the cooling coil 32, and the heat medium 12 is supplied by the cooling coil 32.
Is cooled and the flux contained in the heat medium 12 is deposited. The pump 33 draws the heat medium 12 from the filtering tank 31 and sends the heat medium 12 to the filter 34. The filter 34
Is configured to remove the flux deposited from the cooled heat medium 12 and return it to the carry-in side cooler having the carry-in side cooling coil 8.

The operation of the vapor reflow soldering device shown in FIG. 4 constructed in this way will be described.

The heat medium 12 accumulated at the bottom of the steam generation tank 4 is heated by the heater 7 to boil. The saturated vapor 13 of the heat medium 12 that has been boiled by boiling rises to the upper part in the vapor generation tank 4, heats the soldering member 17, and part of it condenses and falls,
Collect at the bottom of the steam generation tank 4.

The saturated steam 13 that has flowed into the carry-in-side transport path 5 and the carry-out-side transport path 6 has the carry-in side cooling coil 8 and the carry-out side cooling coil 9
It is cooled and liquefied by and is returned to the lower part of the steam generation tank 4 through the return pipe 18. The remaining vapor is exhausted at the loading side
10 and the exhaust side exhaust port 11 to the exhaust gas recovery device 24,
It is liquefied by the exhaust cooling coil 25, part of which is demitasse
It is collected by 26 and collected in the water separator 27. In this water separator 27, the heat medium 12 and water are separated by utilizing the difference in specific gravity.
Is returned to the steam generation layer 4 by the pump 28. On the other hand, the exhaust gas is discharged to the atmosphere or a local exhaust system. In order to improve the recovery rate, low temperature cold water is passed through the exhaust cooling coil 25 by the chiller 29.

Further, the soldering member 17, which is the object to be processed, is the conveyor 16
Thus, initially, it is carried into the preheating chamber 2. The soldering member 17 carried into the preheating chamber 2 is heated by the preheating upper heater 14 and the preheating lower heater 15 and then carried into the steam generation tank 4 of the reflow chamber 1 by the conveyor 16.

The soldering member 17 carried into the steam generation tank 4 by the conveyor 16 is heated by touching the saturated steam 13, and the solder is heated and melted in the steam generation tank 4 by the latent heat of condensation of the saturated steam 13 so that the members are separated from each other. After being soldered, the soldering member 17 enters the carry-out side transport path 6, is gradually cooled, and is forcibly cooled by the cooling fan 19 in the cooling chamber 3 and carried out from the reflow chamber 1.

When the solder is melted in the steam generation tank 4, the flux in the solder is mixed in the heat medium 12. Therefore, in order to remove the flux, the heat medium 12 is transferred from the steam generation tank 4 to the filtering tank 31 of the filtering device 30. Transfer. When the heat medium 12 is cooled, a flux is deposited. Therefore, the heat medium 12 is sent to the filter 34 by the pump 33 to remove the flux, and is returned to the steam generation tank 4 again via the carry-in side cooler.

[Problems to be Solved by the Invention]

By the way, in the above-mentioned conventional technique, the cooling of the heat medium 12 at the time of filtering is not sufficiently taken into consideration, and there are the following problems.

(1) Since the cooling water is constantly flowing through the filtering device 30 having the cooling coil 32, the moisture in the air is condensed and accumulated in the filtering tank 31 when the humidity in the workplace is high. This moisture returns to the steam generation tank 4 and reacts with the thermal decomposition product during boiling to generate hydrogen fluoride, which may corrode the apparatus.

(2) When the heat medium 12 containing the flux is cooled, the temperature of the heat medium 12 is made as low as possible, so that the concentration of the flux in the heat medium is lowered and the filtering effect is enhanced. However, as described in the item (1), there is a problem of moisture in the air, and the cooling temperature of the heat medium 12 is limited. Therefore, tap water or industrial water is used as the cooling water. Therefore, the cooling time varies depending on the season, and the cooling time is long especially in the summer.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to shorten the filtering time during filtering, and to reduce the filtering time without being affected by the change in the outside air temperature depending on the season. Stabilize the
It is an object of the present invention to provide a vapor reflow soldering device capable of enhancing the filtering effect and, at the same time, preventing the dew condensation in the air in the filtering tank of the filtering device during the filtering time and preventing the corrosion of the device.

[Means for Solving the Problems]

In order to achieve the above object, the structure of the vapor reflow soldering apparatus according to the present invention is a steam generation tank for performing soldering by heating the melting of the solder of the object to be processed by bringing saturated steam of a heat medium into contact with the object to be processed. And a reflow chamber having a transfer path for the object to be processed communicating with the inside of the steam generation tank and a cooler for cooling the excess saturated steam in the steam generation tank, and a conveyor for transferring the object to be processed in the transfer path. An exhaust gas recovery device that recovers the heat medium exhausted from the exhaust port provided in the reflow chamber, a cold water supply device that has a function of supplying cold water to the exhaust gas recovery device, and a cold water supply device that collects at the bottom of the steam generation tank. In a vapor reflow soldering device equipped with a filtering device for separating and refining the flux from the heat medium, the exhaust gas recovery device and the cold water supply device are connected by a cooling water pipe. The cooling water pipe and the filtering device are connected by a cold water pipe, and the cooling water for the exhaust gas recovery device is passed through the filtering device only at the time of filtering at the connection portion between the cooling water pipe and the cold water pipe. A valve having a function of watering is provided.

[Action]

In this type of vapor reflow soldering device, in order to improve the recovery rate of the exhaust gas recovery device, low temperature cold water is used,
The exhaust gas containing another medium is being cooled.

The filtering is performed according to the following procedure. That is,
After the normal work is completed, the heater power for the steam generating tank is shut off, the liquid in the steam generating tank is transferred to a filtering tank while the temperature is high, and after cooling, the mixed flux is removed by filtering.

Since the heat load of the exhaust gas recovery device is reduced during filtering, the cold water for the exhaust gas recovery device is guided to the filtering device through the cold water pipe by switching the valve, and the heat medium containing the flux is cooled.

Since cold water of a certain temperature passes through the filtering device, the filtering time can be shortened compared to tap water or industrial water that was conventionally used as cooling water, and it does not affect seasonal changes in outside temperature. The filtering time is stable, the filtering effect is enhanced, and the dew condensation of water in the air in the filtering tank can be prevented.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a system diagram of a vapor reflow soldering apparatus according to an embodiment of the present invention. In the figure, those having the same reference numerals as those in FIG. 4 are the same parts as those in the prior art, and therefore the description thereof will be omitted.

In the embodiment shown in FIG. 1, the forward cooling water pipe 35 connecting the exhaust cooling coil 25 and the chiller 29 of the exhaust recovery device 24.
Of the return side cooling water piping 36, the return side cooling water piping 36 is provided with a forward side cold water piping 37 and a return side cold water piping.
The cooling coil 32 of the filtering device 30 is connected via 38.

The cooling water pipe 36 is provided with three-way valves 39, 40 at the connection portion of the cooling water pipes 37, 38.

At the time of filtering, the three-way valves 39, 40 are switched to use the cooling water for the exhaust gas recovery device in the filtering device.

Filtering is performed in the following procedure.

That is, at the bottom of the steam generation tank 4 after the reflow work,
The heat medium 12 containing the flux mixed when the solder is melted is accumulated. In order to carry out the filtering, firstly the heating medium 12 is introduced into the filtering tank 31 of the filtering device 30.

Then, the cold water is once passed from the chiller 29 through the cooling water pipe 35 to the exhaust cooling coil 25 of the exhaust recovery device 24.
After the exhaust gas is cooled in the exhaust gas recovery device 24, the cold water is passed through the cold water pipe 37 to the cooling coil 32 of the filtering device 30 by switching the three-way valve 39 from the cooling water pipe 36. This cold water passes through the cooling coil 32, then the cold water pipe 38, and returns to the chiller 29 again via the cooling water pipe 36 by switching the three-way valve 40.

By passing cold water through the cooling coil 32 of the filtering device 30, the heat medium 12 containing the flux introduced into the filtering tank 31 is cooled and the flux is deposited. The heat medium 12 on which the flux has been deposited after being cooled is sent to the filter 34 by the pump 33, the flux is removed by the filter 34, and then the heat medium 12
Is sent to an inlet side cooler having an inlet side cooling coil 8,
The steam is returned to the steam generation tank 4 via the carry-in side cooler, and the filtering is completed.

In this embodiment, at the time of filtering, cold water having a low temperature of, for example, 5 to 10 ° C., which is supplied from the chiller 29 to the exhaust gas recovery device 24, is passed to the cooling coil 32 of the filtering device 30. Since the cold water passes through the filtering device, the filtering time can be shortened compared to the tap water or industrial water that was conventionally used as cooling water, and it is not affected by the change in the outside air temperature depending on the season. The filtering time is stable and the filtering effect can be enhanced.

Moreover, in this embodiment, the cooling coil 32 of the filtering device 30 is made to pass the cold water for the exhaust gas recovery device 24 only at the time of filtering, so that the moisture in the air is contained in the filtering tank 31 of the filtering device 30. It is possible to prevent a phenomenon in which dew condensation causes corrosion of the accumulation device.

Next, FIG. 2 is a system diagram of a vapor reflow soldering apparatus according to another embodiment of the present invention. In the figure, those having the same reference numerals as those in FIG.

In the embodiment shown in FIG. 2, the cooling water pipe 35 connecting the exhaust cooling coil 25 of the exhaust gas recovery device 24 and the chiller 29 and the filtering device 30 are connected by the cold water pipe 37, and the cooling water pipe 35 and the cold water are connected. A three-way valve 39 is provided at the connection with the pipe 37, and a three-way valve 40 is provided at the connection between the cooling water pipe 36 and the cold water pipe 38 in the same manner.

In this embodiment, cold water is filtered directly from the chiller 29 without passing through the exhaust gas recovery device 24 during filtering.
Since it passes through the inside of 30, the cold water having a temperature lower than that of the embodiment shown in FIG. 1 can be used as the cooling water for filtering. Therefore, the filtering time becomes shorter than that of the embodiment shown in FIG.

Further, similar to the embodiment shown in FIG. 1, the filtering time is stable and the filtering effect is enhanced without being affected by the change in the outside temperature depending on the season, and moreover, the dew condensation of the moisture in the air in the filtering tank is prevented. Can be prevented.

Next, FIG. 3 is a system diagram of a vapor reflow soldering apparatus according to still another embodiment of the present invention. First in the figure
The parts having the same reference numerals as those in the figure are the same parts as those in the previous embodiment, and therefore their explanations are omitted.

In the embodiment shown in FIG. 3, similar to the embodiment shown in FIG. 2, the cooling water pipe 35 connecting the exhaust cooling coil 25 of the exhaust gas recovery device 24 and the chiller 29 and the filtering device 30 are connected to the cold water pipe 37. A three-way valve 39 is provided at the connection between the cooling water pipe 35 and the cold water pipe 37, and a three-way valve 40 is provided at the connection between the cooling water pipe 36 and the cold water pipe 38.

Therefore, similarly to the embodiment shown in FIG. 2, the filtering time is stable and the filtering effect is enhanced because it is not affected by the change in the outside temperature depending on the season.

Further, in the embodiment shown in FIG. 3, the cooling water pipes 35, 36
In the exhaust recovery device 24 side than the three-way valve 39, 40, the valve 41,
42 is provided so that water for cooling the exhaust gas can be passed from the outside.

As a result, similarly to the embodiment shown in FIG. 1, it is possible to operate the exhaust gas recovery device 24 while performing filtering to recover the steam containing the heat medium remaining in the steam generation tank 4.

According to each of the above-described embodiments, cold water having a constant temperature at a low temperature on the side of the exhaust recovery device is passed to the filtering device at the time of filtering through the cold water pipe and the valve, the heat medium containing the flux is cooled, and the flux is deposited. Since the temperature of the heat medium is higher than that when cooling it with tap water or industrial water, it has the effect of shortening the filtering time and is affected by changes in the outside temperature depending on the season. Therefore, the filtering time is stable and the filtering effect is enhanced.

Further, according to each of the above-mentioned embodiments, by switching the valve, the low temperature cold water is passed through the filtering device only at the time of filtering, so that the moisture in the air is condensed in the filtering tank of the filtering device. This has the effect of eliminating problems such as corrosion of the accumulation device.

〔The invention's effect〕

As described in detail above, according to the present invention, cold water is supplied to the filtering device during the filtering to shorten the filtering time, and the filtering time is stabilized without being affected by the change in the outside temperature according to the season, and the filtering is performed. A vapor reflow soldering device that enhances the effect and prevents the condensation of moisture in the air in the filtering tank of the filtering device and cools the device without cooling the inside of the filtering tank outside the filtering time can do.

[Brief description of drawings]

FIG. 1 is a system diagram of a vapor reflow soldering apparatus according to an embodiment of the present invention, FIG. 2 is a system diagram of a vapor reflow soldering apparatus according to another embodiment of the present invention, and FIG. FIG. 4 is a system diagram of a vapor reflow soldering apparatus according to still another embodiment of the present invention, and FIG. 4 is a system diagram of a conventional vapor reflow soldering apparatus. 1 ... Reflow chamber, 2 ... Preheating chamber, 3 ... Cooling chamber, 4 ...
… Steam generation tanks, 5,6 …… Inlet side and unload side transport paths, 7 ……
Heater, 8, 9 ... Cooling coil on loading side, unloading side, 10,11
…… Inlet side, unload side exhaust port, 12 …… heat medium, 13 …… saturated steam, 16 …… conveyor, 17 …… soldering member, 24 ……
Exhaust gas recovery device, 25 ... Exhaust cooling coil, 29 ... Chiller,
30 …… filtering device, 31 …… filtering tank, 32 …… cooling coil, 34 …… filter, 35,36 …… cooling water piping, 37, 38 …… cold water piping, 39, 40 …… three-way valve, 41, Four
2 ... valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 63-90361 (JP, A) JP 63-13666 (JP, A) JP 62-238069 (JP, A)

Claims (1)

[Claims] 1. A steam generation tank for contacting a saturated steam of a heat medium with the processing object to heat and melt the solder of the processing object for soldering, and a conveyance path for the processing object communicating with the inside of the steam generation tank. And a reflow chamber having a cooler that cools excess saturated steam in the steam generation tank, a conveyor that conveys an object to be processed in the conveyance path, and heat discharged from an exhaust port provided in the reflow chamber. A vapor provided with an exhaust gas recovery device for recovering the medium, a cold water supply device having a function of supplying cold water to the exhaust gas recovery device, and a filtering device for separating and purifying the flux from the heat medium accumulated at the bottom of the steam generation tank. In the reflow soldering device, the exhaust gas recovery device and the cold water supply device are connected by a cooling water pipe, and the cooling water pipe and the filtering device are connected by a cold water pipe. In addition to the above, the connection portion between the cooling water pipe and the cold water pipe is provided with a valve having a function of passing cold water for the exhaust gas recovery device to the filtering device only at the time of filtering. Vapor reflow soldering equipment.