JPH084928B2 - Work quenching equipment in vapor phase soldering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention provides latent heat of vaporization during a phase change to a work to melt the cream solder previously applied to the work, or The present invention relates to a vapor-phase soldering device that applies vaporization latent heat to a solder-coated work to perform fading, and is characterized by a work quenching device that can rapidly cool a work immediately after soldering.

(Prior Art) As shown in FIG. 4, an in-line vapor-phase soldering apparatus is used for an inert liquid contained in the bottom of a steam tank 11.
12 is heated by the heater 13 to evaporate, a saturated vapor phase 14 is formed inside the steam tank 11, and passes through a carry-in port 15 provided on one side of the steam tank 11 by the work transfer conveyor 16 to the steam tank 11 Latent heat of vaporization of the saturated vapor phase 14 is applied to the work W carried into the inside of the work W, and the cream solder interposed between the printed wiring board as the work and the board mounting component is melted. The work W is taken out through a carry-out port 17 provided on the other side of the steam tank 11.

The saturated vapor phase 14 formed inside the steam tank 11 is kept in a certain area by the carry-in inlet portion 15, the carry-out outlet portion 17 and the steam condensers 18 provided on the upper inner wall of the steam tank 11, respectively, and externally. Outflow to

Then, the temperature of the work W conveyed by the conveyor 16 is raised by the external preheater 21 as shown in FIG.
The elevated temperature is maintained by the reflow soldering by the saturated vapor phase 14, and the product is carried out to the outside via the carry-out port 17. Although a work cooling device 23 for rapidly cooling the work is shown in FIG. 4 between the conveyor 16 and the upper and lower vapor condensing devices 18, there is no such work device in the past.

The conventional vapor-phase soldering device is the vapor condensing device 18
Performs both condensation of steam and cooling of the work. Therefore, conventionally, as shown by the chain double-dashed line in FIG. 5, the rate of decrease in the work temperature immediately after soldering is slow. When the temperature drop of the work is slow, the solder joint strength tends to be weak.

If the work cooling device 23 is provided between the conveyor 16 and the upper and lower vapor condensing devices 18 at the carry-in port 17, first, an air pipe is installed between the conveyor 16 and the upper and lower vapor condensing devices 18. It is conceivable that a small amount of air is blown from the upper and lower air pipes onto the work, and the work is cooled by these small amounts of air, but in this case, the air blown into the carry-out port is expensive in the tank. There is a problem that various steam easily leaks to the outside.

It is also conceivable to configure the work cooling device with a heat transfer medium such as a cooling coil or a thermomodule, but since these must be accommodated in a narrow space between the conveyor 16 and the upper and lower vapor condensing devices 18, In the case of the cooling coil, the cooling efficiency is inevitably low, and only the work temperature lowering curve shown by the dotted line in FIG. 5 can be obtained, and in the case of the thermomodule, the structure becomes complicated in the narrow space. There's a problem.

(Problems to be Solved by the Invention) As described above, conventionally, there is nothing that can rapidly cool a work immediately after reflow soldering by a vapor phase soldering device, and an increase in solder joint strength due to work quenching. Although desired, it has not been realized in the past.

An object of the present invention is to provide a work cooling device that can be provided as close as possible to the work transfer path in a narrow space along the work transfer path, thereby effectively quenching the work and increasing the solder joint strength. Is to try.

[Structure of Invention]

(Means for Solving Problems) According to the present invention, a work-carrying-in port 15 is provided on one side of the steam tank 11, and a work-carrying-out port 17 is provided on the other side of the steam tank 11. Is provided, and the vapor phase 14 formed inside the vapor tank 11 is kept in a certain region by the vapor condensing device 18 provided at the carry-in section 15 and the carry-out section 17, and the latent heat of vaporization of the vapor phase 14 In the vapor phase soldering apparatus in which the work is conveyed to the work W carried into the steam tank 11 by the work conveyer 16 and the work is reflow-soldered, the work is cooled at the carry-out port 17 together with the steam condensing device 18. A device 23 is provided and this work cooling device 23 is provided.
The heat absorption part 42 of the heat pipe 41 is arranged in the vicinity of the conveyor 16 along the work transfer conveyor 16, and the remaining part of the heat pipe 41 is drawn out of the carry-out part 17.
An external cooler 44 is provided in the heat radiating section 43 located on the external drawing side of the heat pipe 41.

(Operation) In the present invention, the heat in the space in the vicinity of the work transfer conveyor 16 of the carry-out section 17 is transported from the heat absorbing section 42 to the heat dissipation section 43 outside the carry-out section 17 by the heat pipe 41, and the carry-out section is carried out. By being forcibly cooled by the cooler 44 outside the machine, the work W is subjected to the rapid cooling action from the heat pipe 41 located in the vicinity at the carry-out port 17, and is rapidly lowered to a temperature at which a strong solder joint strength is obtained. To do.

(Example) Hereinafter, the present invention will be described in detail with reference to the examples shown in the drawings.

FIG. 1 shows a vapor condensing device 18 (FIG. 4) at the carry-out port 17. This vapor condensing device 18 works
On the upper and lower sides of the conveyor 16 that conveys
A large number of heat absorbing parts 32 of the heat pipe 31 formed in a U shape are inserted along the conveyor 16 as shown in FIG. 2, and the parts other than the heat absorbing part of the heat pipe 32 are drawn out to the outside of the carry-out port part 17. A large external cooler 34 is provided in the heat dissipation portion 33 located on the outside extraction side of the heat pipe 31. As shown in FIG. 1, the heat absorbing portion 32 of the heat pipe 31 is provided with a large number of heat absorbing fins 35. The external large-sized cooler 34 is a water-cooled cooler whose temperature can be adjusted, and as shown in FIG. 2, a serpentine pipe 36 for receiving the cooling water whose temperature is adjusted so as not to form a dew point on the surface of the water conduit. Is piped. The work transfer conveyor 16 includes a pair of endless chains arranged in parallel with a work receiving portion.

Further, in FIG. 1, the work cooling device 23 in the carry-out section 17 is shown.
(FIG. 4) is shown. This work cooling device 23 is
A conveyor that conveys the work W inside the carry-out section 17.
A large number of heat absorbing portions 42 of the heat pipe 41 formed in a U shape are respectively inserted near the upper side and the lower side of 16 along the conveyor 16 as shown in FIG. Parts other than this part are drawn out of the carry-out port 17, and an external small-sized cooler 44 is provided in the heat dissipation part 43 located on the outside drawing side of the heat pipe 41. The heat absorbing portion 42 of the heat pipe 41 is provided with a large number of heat absorbing fins 45.

Like the heat pipe 31, the heat pipe 41 has a capillary material lined on the inner wall of a sealed metal pipe whose both ends are closed, and the inside of the metal pipe is in a highly depressurized state, and heat of water, alcohol, freon, etc. It is a heat transport device in which an appropriate amount of a medium is enclosed, and is known to have extremely high thermal conductivity.

In this heat pipe, when heat is applied to the heat absorbing portion 42 from the heat absorbing fins 45, the heat medium under reduced pressure in the pipe boils and evaporates at a low temperature, and absorbs latent heat of vaporization when vaporized,
Then, the vapor in the pipe moves from the heat absorbing portion 42 to the heat radiating portion 43 at a speed equal to the speed of sound, the vapor in the pipe is condensed and returned to the liquid in the heat radiating portion 43, and the latent heat of condensation is released when liquefying, and The condensed and liquefied heat medium returns to the heat absorbing section 42 through the capillary lining material. Such circulation of the heat medium proceeds continuously, and heat is continuously transferred from the heat absorbing section 42 to the heat radiating section 43.

As shown in FIG. 3, the external small cooler 44 is
It is an electric cooler using a thermo module 51 utilizing the Peltier effect, and the heat dissipation part 43 of the heat pipe 41.
On the other hand, between the heat absorbing plate 53 that is in contact with the mounting bracket 52 and the heat radiating plate 54 located on the lower side, the thermo module 51 is sandwiched and integrated, and by the thermo module 51, An endothermic plate that absorbs the heat emitted from the heat dissipation portion 43
The heat is absorbed through 53 and is released to the atmosphere through a heat dissipation plate 54 and further through heat dissipation fins (not shown) provided below the heat dissipation plate 54.

Next, the operation of this embodiment will be described. The heat energy for condensation released from the saturated vapor phase 14 to the heat absorbing part 32 of the heat pipe 31 is carried out by the heat pipe 31.
It is hot-rolled to a heat radiating section 33 outside of 17, and is forcibly cooled by a water-cooling cooler 34 outside of the carry-out section 17. In this way, the heat energy is transported to the outside of the carry-out port 17 and forcedly cooled outside, so that the vapor is condensed without passing any water into the carry-out port 17. Therefore, there is no possibility that the cooling water will leak into the carry-out port portion 17, and when it leaks, bumping or explosion that occurs when the cooling water comes into contact with the high temperature inert liquid 12 can be prevented.

The high-temperature work W reflow-soldered by the saturated vapor phase 14 is rapidly cooled at the carry-out port 17 by a work cooling device using a thermo module 51. That is, the heat released from the work W conveyed through the carry-out section 17 is efficiently absorbed by the heat absorbing section 42 of the heat pipe 41 through the heat absorbing fins 45, and the heat is dissipated outside the carry-out section 17 by the heat pipe 41. The heat is transferred to the portion 43 and forcedly cooled by the external thermo-module cooler 44.
In this way, thermal energy is transported to the outside of the carry-out port 17,
Since it is forcibly cooled externally, the atmosphere in the vicinity of the conveying path of the work W is rapidly cooled without passing any water into the carry-out port 17, and the work W passing through this atmosphere is rapidly cooled at a high speed. As shown by the solid line in FIG. 5, the temperature drops sharply to 183 ° C. where a large solder joint strength can be obtained, in a short time.

The thermo module type external cooling 44 may be a cooling water flow type cooler.

〔The invention's effect〕

According to the present invention, as the work cooling device, the heat absorption part of the heat pipe is arranged in the vicinity of the work transfer conveyor at the carry-out port, and the remaining part of the heat pipe is outside the carry-out part. Since the external cooling device is provided in the heat dissipation portion that is drawn out and located on the external drawing side of the heat pipe, first, the work cooling device can be provided in a narrow space along the work transfer path. Then, the work cooling device provided as close as possible to the work transfer path can effectively and rapidly cool the work immediately after soldering to increase the solder joint strength.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a work quenching device in a vapor phase soldering device of the present invention, FIG. 2 is a perspective view showing the outside of the work carry-out port portion, and FIG. 3 is a work cooling device. FIG. 4 is an enlarged perspective view, FIG. 4 is a cross-sectional view of the in-line type vapor phase soldering device, and FIG. 5 is a graph showing a work temperature characteristic curve thereof. 11 …… Steam tank, 14 …… Steam phase, 15 …… Carrier port, 16 ……
Work transfer conveyor, 17 …… Unloading part, 18 …… Steam condenser, 23 …… Work cooling device, 41 …… Heat pipe, 42
…… Heat absorption part, 43 …… Heat dissipation part, 44 …… External cooler, W ……
work.

Claims (4)

[Claims] 1. A steam formed inside a steam tank, wherein a work-carrying-in port is provided on one side of the steam tank and a work-carrying-out port is provided on the other side of the steam tank. The phase is kept in a certain region by the vapor condensers provided at the carry-in part and the carry-out part, and the latent heat of vaporization of the vapor phase is given to the work carried into the steam tank by the work transfer conveyor. In the vapor-phase soldering device in which the reflow soldering is performed, a work cooling device is provided in the carry-out port together with the vapor condensing device, and the work cooling device is a heat pipe along the work transfer conveyor in the vicinity of the conveyor. The heat absorbing parts of the heat pipe are arranged, and the remaining part of the heat pipe is drawn out to the outside of the carry-out part. A work cooling device in a vapor phase soldering device. 2. The work quenching device in the vapor phase soldering device according to claim 1, wherein the heat absorbing portion of the heat pipe has heat absorbing fins. 3. The work quenching device in the vapor phase soldering device according to claim 1, wherein the external cooler is a cooler using a thermo module. 4. The work quenching device in a vapor phase soldering device according to claim 1, wherein the external cooler is capable of controlling temperature.