JPH035269B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention collects the vapor of a heat transfer liquid used as a heat medium for melting solder paste used to attach electronic components to a printed circuit board and leaks it to the outside. This invention relates to a vapor phase soldering type soldering device which prevents the above.

[Conventional technology]

FIG. 2 is a side sectional view showing a conventional vapor phase soldering type soldering device, in which 1 is a printed circuit board, 2 is a chip component such as a resistor or capacitor, 3 is a solder paste, and 4 is the printed circuit board 1. 5 is a belt conveyor for carrying and conveying the soldering device. 6 is a heated liquid tank of the soldering device 5; 7 is a fluorine-based heat transfer liquid having a boiling point higher than the melting point of the solder paste 3; company's trademark name). A heater 8 heats the heat transfer liquid 7 and generates heated steam 7a. Reference numeral 9 is an inlet for the printed circuit board 1, 10 is an inlet passage, 11 is an outlet for the soldered printed circuit board 1, 12 is an outlet passage, and 13 is a cooling pipe for condensing the steam 7a. The coolers 14 and 15 are ventilation ports for forcing the uncondensed steam 7a to be discharged to the outside in order to prevent the uncondensed steam 7a from being discharged from the inlet 9 and the outlet 11.

The conventional soldering apparatus is constructed as described above, in which the heat transfer liquid 7 is boiled by the heater 8 and turned into steam 7.
a, and using the thermal energy possessed by this steam 7a as a heat medium, it is transferred from the inlet 9 to the belt conveyor 4.
The solder paste 3 of the printed circuit board 1 carried in is melted, and then the printed circuit board 1 is carried out from the outlet 11, and the solder paste 3 is cooled in the air and solidified, so that the chip component 2 is transferred to the printed circuit board 1. will be installed on the Further, the vapor 7a is condensed in the cooler 13, becomes a liquid, drops onto the heat transfer liquid 7, and is collected.

[Problem that the invention seeks to solve]

By the way, in the conventional soldering apparatus 5, since the cooler 13 is provided only in the upper part of the heating liquid tank 6, the carry-in passage 10, and the carry-out passage 12, not all of the steam 7a is condensed, and the remaining large amount is steam 7
There was a problem that since the a was directly discharged from the ventilation ports 14 and 15, the amount recovered was small.

Therefore, if a cooler 13 is provided below the belt conveyor 4 on the inner peripheral surface of the heated liquid tank 6, the steam 7a
Although the amount of steam 7a recovered increases, on the other hand, the amount of steam 7a reaching the belt conveyor 4 decreases, resulting in problems such as an insufficient amount of heat to melt the solder paste 3.

Furthermore, since the heat transfer liquid 7 is very expensive, if a large amount of the steam 7a is discharged without being recovered, a large amount of new heat transfer liquid 7 must be replenished, which reduces the manufacturing cost. There were problems such as rising prices and being uneconomical.

This invention was made to solve the above problems, and makes it possible to recover most of the vapor of the heat transfer liquid without reducing the amount of vapor for melting the solder paste. The purpose of the present invention is to obtain a soldering device that has the following properties.

[Means for solving problems]

The soldering device according to the present invention includes an inner tank having a through hole formed inside the heating liquid tank through which a heat transfer liquid in the heating liquid tank flows; A cooler provided below the belt conveyor on the inner peripheral side, and an inclined passage branching diagonally downward from a predetermined position of each of the carry-in side passage and the carry-out side passage and connecting to the heated liquid tank downwardly, respectively; Furthermore, a steam guide plate for guiding steam upward is provided at the carry-in port of the carry-in side passage and the carry-out port of the carry-out side passage.

[Effect]

In this invention, since the cooler is located outside the inner tank, the amount of steam for melting the solder paste can be maintained without cooling the vapor of the heat transfer liquid generated in the inner tank. In addition, the amount of steam flowing into the carry-in and carry-out passages decreases, and the steam in the carry-in and carry-out passages is cooled by the cooler and drips, flows through the inclined passage and is collected into the heat transfer liquid in the heating liquid tank. be done. Further, steam discharged from the carry-in port and the carry-out port is guided to each steam guide plate and collected.

〔Example〕

FIGS. 1a and 1b show an embodiment of the present invention, with FIG. 1a being a side sectional view and FIG. 1b being a sectional view taken along the line -- in FIG. 1a. In these figures, the same symbols as in FIG. 2 indicate the same parts, 21 is a soldering device, 22 is a heating liquid tank, 23 is an inner tank provided inside the heating liquid tank 22, and the upper part is the bending part 2.
3a and 23b are formed, and a heating liquid tank 22 is provided below.
A through hole 23c is formed to communicate with the heat transfer liquid 7 inside. 24 is a loading port for the printed circuit board 1;
5 is a carry-in side passage, 26 is a carry-out port, and 27 is a carry-out side passage, and the lower surfaces of each passage 25, 27 are both gently inclined downwardly toward the heated liquid tank 22, with a slope 25a,
27a. 28 to 33 are coolers for condensing the steam 7a, and 34 and 35 are slopes branching diagonally downward from respective predetermined positions of the passages 25 and 27 and connected to the heating liquid tank 22 downward. It is a passage. Reference numerals 36 and 37 are steam guide plates for the steam 7a provided at the loading port 24 and the loading port 26, which are provided to collect the steam 7a discharged from the loading port 24 and the loading port 26 without discharging it to the outside. It is. 38 is the soldering device 2
1 with a cover provided on the top of the steam guide plate 36, 3.
This is for recovering steam 7a from 7.

Furthermore, the cooler 28 is provided above the belt conveyor 4 on the inner periphery of the heated liquid tank 22 . The cooler 29 is provided on the inner periphery of the heated liquid tank 22 and below the belt conveyor 4 at approximately the same level as the bent portion 23b of the inner tank 23 or the inclined passages 34, 35, and is connected to the inner tank 22 and the cooler 29. The gap between the coolers 28 and 28 is narrower. The coolers 30, 31 are installed obliquely along the inclined passages 34, 35. Coolers 32 and 33 are provided around the outer periphery of each passage 25 and 27.

In the soldering device configured as above,
A printed circuit board 1 is conveyed by a belt conveyor 4,
The solder paste 3 is melted by the vapor 7a of the heat transfer liquid 7 heated by the heater 8, then carried out, solidified by cooling, and the chip component 2 is mounted on the printed circuit board 1, as in the conventional case. .

On the other hand, the heated steam 7a rises in the inner tank 23, melts the solder paste 3, and then enters the cooler 28.
is cooled and condensed, and drips as water droplets from between the cooler 28 and the outside of the inner tank 23. Further, the steam 7a accumulated below the belt conveyor 4 in the heating liquid tank 22 is cooled by the cooler 29, and the steam 7a flowing toward the loading port 9 and the loading port 11 is transferred to the coolers 30, 31, 32 and 33, flows along the inclined surfaces 25a and 27a, passes through the inclined passages 34 and 35, and returns to the heated liquid tank 22. Furthermore, the entrance 24,
The steam 7a remaining near the outlet 26 is transferred to the steam guide plate 3.
6 and 37 into the cover 38, and is recovered by a recovery means (not shown).

〔Effect of the invention〕

As explained above, the present invention provides an inner tank in which a through hole is formed inside the heating liquid tank through which the heat transfer liquid in the heating liquid tank conducts, and a connection between the heating liquid tank and the inner tank. A cooler provided below the belt conveyor on the inner peripheral side, and an inclined passage branching diagonally downward from a predetermined position of each of the carry-in side passage and the carry-out side passage and connecting to the heated liquid tank downwardly, respectively; Furthermore, since the carry-in port of the carry-in side passage and the carry-out port of the carry-out side passage are equipped with steam guide plates for guiding the steam upward, the amount of heat transfer liquid vapor required to melt the solder paste can be reduced. In particular, most of the steam passing through the inlet and outlet passages and the used steam discharged from the inlet and outlet can be recovered, so there is almost no need to replenish expensive heat transfer fluid, making it economical. It has the advantage of being able to reduce product prices.

[Brief explanation of the drawing]

Figures 1a and b show one embodiment of the present invention, where Figure 1a is a side sectional view, Figure 1b is a sectional view taken along the - line of Figure 1a, and Figure 2 is a conventional baseboard. FIG. 2 is a side sectional view showing a puff-aid soldering type soldering device. In the figure, 1 is a printed circuit board, 2 is a chip component, and 3
Solder paste, 4 is a belt conveyor, 7 is a heat transfer liquid, 7a is steam, 8 is a heater, 21 is a soldering device, 22 is a heating liquid tank, 23 is an inner tank, 24 is a loading port, 25 is a loading side passage , 26 is an exit, 27
28 to 33 are coolers, 34 and 35 are unloading passages,
3 is an inclined passage, 36 and 37 are steam guide plates, and 38 is a cover.

Claims (1)

[Claims] 1 A belt conveyor that transports a printed circuit board with chip components arranged on solder paste applied in advance, a heat transfer liquid having a boiling point higher than the melting point of the solder paste, and a heat transfer liquid that is heated and generated. a heating liquid tank for melting the solder paste of the printed circuit board by the steam generated by the heating liquid; an inlet side passage and an unloading side passage connected to the heated liquid tank and serving as a conveyance path for the printed circuit board; and a heating liquid tank provided above the heating liquid tank. A vapor phase soldering type soldering device comprising: a cooler for cooling the vapor; , a cooler provided below the belt conveyor on the inner peripheral side of the heated liquid tank between the heated liquid tank and the inner tank; an inclined passage that branches downward and is connected to the heating liquid tank downwardly; and a steam guide plate that guides the steam upward to the carry-in port of the carry-in side passage and the carry-out port of the carry-out side passage; A soldering device characterized by comprising: