JPH07326855A - Jet stream soldering device and method - Google Patents

Abstract

PURPOSE:To suppress the growth of solder dross by a simple and compact structure without using a large quantity of inert gas by a method wherein the jet stream of fused solder is dropped into the fused solder in a solder vessel passing through the upper surface of the wing part, and the falling jet stream solder is pinched by feeding inert gas from the lower part of the wing part and the lower part of a cover. CONSTITUTION:A solder jet-stream nozzle 4 has a nozzle main body 6, having a slot 5 in the center, and a pair of axis parts 7 and 8 horizontally extending to the opposite direction pinching the slot 5 to be connected to the upper part of the nozzle main body 6. Jet stream solder S coming out from a slot 5 passes the upper surface of the wiring parts 7 and 8, and drops spontaneously to the fused solder surface in a solder vessel 1. Also, a cover is attached to the solder vessel 1 with the optimum interval corresponding to the wiring parts 7 and 8 respectively. Gas feeding holes 17 to 20 are provided on the lower part of the pair of wiring parts 7 and 8 and on the lower part of slide covers 11b and 12b. The inert gas fed from those holes passes through the gaps 9 and 15, and 10 and 16, and covers the jet stream solder in a pinching manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic soldering apparatus and method used for joining predetermined parts in electronic parts such as printed circuit boards and circuit boards.
In particular, the present invention relates to a jet automatic soldering apparatus and method in which molten solder is jetted in a solder bath, and a portion to be joined such as an electronic component is brought into contact with the molten solder jet to automatically perform soldering.

[0002]

2. Description of the Related Art In such a jet automatic soldering apparatus, the jetted solder is extremely liable to be oxidized by being combined with oxygen in the air, and a large amount of solder dust generated by this may affect work environment, quality, cost, etc. It causes various problems. In other words, the generation of a large amount of solder scrap not only wastes the solder, but also requires the work of removing the solder several times a day, which causes a cost increase and causes a problem such as a heavy metal obstacle to an operator. ing.

Further, solder debris floating on the liquid surface of the solder bath is taken up by the shaft of the jet flow delivery device, and during the jet flow, the solder debris adheres to the solder adhering portion of the electronic component from the tip of the nozzle, resulting in poor conduction and aging. It often caused serious quality problems such as defective changes. Furthermore, since the solder residue covers the molten solder liquid surface in the solder bath and the solder liquid surface constantly changes in accordance with the above-mentioned solder residue removal work, it is extremely difficult to maintain and manage the solder liquid surface. . This results in unstable changes in the solder jet surface level in contact with electronic components such as printed circuit boards, and as a result, constant contact with electronic components cannot be obtained, which has a serious effect on the quality of soldering. ing.

In order to solve such a problem, by supplying an inert gas such as N 2 gas along the solder jet and covering the periphery of the jet with the inert gas, the jet solder does not come into contact with oxygen in the atmosphere as much as possible. In this way, a soldering device intended to suppress the generation of solder residue has been proposed (see US Pat. No. 5,203,489).

However, according to this method, the entire periphery of the solder jet from the nozzle is covered with N ₂ gas or the like, the entire periphery is made to have a low oxygen concentration atmosphere of about 1000 to 10 ppm, and the containment accuracy is improved. Requires a high-purity, high-capacity nitrogen generator. For this purpose, there are a method of using liquefied nitrogen by installing an outdoor storage tank facility and a high-pressure gas pipe, a method of using a liquefied nitrogen-containing cylinder, a method of extracting a large amount of nitrogen gas from the atmosphere, and the like.
However, if a method of using liquefied nitrogen by installing an outdoor storage tank facility and high-pressure gas piping or a method of extracting a large volume of nitrogen gas from the atmosphere is adopted, the equipment investment cost and running cost will be extremely high, and However, using a cylinder containing liquefied nitrogen can reduce the capital investment cost, but there is a problem that approval for high-pressure gas and explosion-proof measures are required.

There is also a method in which an encapsulating box is arranged above the electronic component carrying section and the interior of the box is filled with nitrogen gas in order to prevent solder oxidation, but it is necessary to carry the electronic component. Therefore, it is difficult to completely seal the inside of the box from the outside, and as a result, it has not been possible to effectively prevent the solder from being effectively oxidized. Further, according to this method, there is a problem that it takes a long time to remove the solder scraps due to the enclosing box, which easily causes a heavy metal obstacle.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a very simple and compact structure and does not require the use of a large amount of inert gas. An object of the present invention is to provide a jet soldering apparatus and a jet soldering method capable of soldering an electronic component or the like while sufficiently suppressing generation of solder residue.

[0008]

In order to solve the above-mentioned problems, a jet soldering device of the present invention has a solder bath for containing molten solder, and a central part projecting above the molten solder and having a central portion. Nozzle body having a slot for ejecting molten solder to the part, and a pair of sleeves formed so as to extend slightly from the molten solder liquid surface toward the molten solder liquid surfaces on both sides from the nozzle body upper part And a pumping means for jetting the molten solder from a slot of the solder jet nozzle and forming a solder flow so that the jetted solder falls from the upper surface of the sleeve portion into the molten solder in the solder bath. And a gap for passing jet solder is formed between the sleeve portion and the sleeve portion, and extends toward the molten solder liquid surface so as to be slightly separated from the molten solder liquid surface in the solder bath, and at least the solder bath A cover means for covering the portion and at least a lower portion of the sleeve portion and a lower portion of the cover means, and an inert gas for discharging an inert gas so as to sandwich the jet solder falling into the molten solder in the solder bath from both sides thereof. The gas supply means and the carrying means for carrying the part along a predetermined carrying path so that the part of the part to be soldered may come into contact with the jet solder. .

According to a second aspect of the present invention, there is provided the jet soldering device according to the first aspect, wherein the inert gas supply means is from 10,000 to 50.
It is configured to supply an inert gas containing 000 ppm of oxygen.

According to a third aspect of the present invention, in the jet soldering apparatus according to the first aspect, the inert gas supply means allows compressed air to permeate the hollow fiber membrane and separates and concentrates nitrogen due to the difference in permeability between oxygen and nitrogen. It is configured to be connected to a nitrogen gas generator.

According to another aspect of the present invention, there is provided a jet soldering method for a component, wherein the molten solder is jetted from a nozzle projecting above the molten solder in a solder bath, and the jet solder is brought into contact with a portion of the component to be soldered. A method of automatically soldering a component for transporting the component, wherein an inert gas is supplied from both sides of the jet solder so as to sandwich the jet solder falling into the molten solder in the solder bath, It is characterized by suppressing the oxidation of the solder due to the drop of the solder.

According to a fifth aspect of the present invention, in the jet soldering device according to the fourth aspect, the inert gas is also applied to a portion where a movable part of the device for generating the jet flow of the molten solder comes into contact with the liquid surface of the molten solder in the solder bath. It is configured to be supplied.

[0013]

According to the jet soldering device of the first aspect, the jet of the molten solder jetted from the solder jet nozzle drops through the upper surface of the sleeve into the molten solder in the solder bath. At this time, the drop jet solder is sandwiched by the inert gas supplied by the inert gas supply means provided in the lower part of the sleeve portion and the cover means. Usually, when the jet solder falls on the liquid surface of the molten solder, it is easy for air to be entrapped, and thus the solder is most likely to be oxidized at this time. On the other hand, according to the present jet soldering device, since the jet solder in the most oxidizable position is sandwiched and covered with the inert gas, the oxidation of the solder can be suppressed very efficiently with a small amount of the inert gas. . As a result, it is possible to reduce the amount of solder scraps with a small-sized device, and it is possible to further reduce the problems caused by the above-mentioned solder scraps.

According to the jet soldering device of the second aspect, although a low-purity inert gas containing 10,000 to 50,000 ppm of oxygen is used, a very efficient and sufficient effect can be obtained. No need for a large inert gas generator.

According to the jet soldering device of the third aspect, compressed air is permeated through the hollow fiber membrane, nitrogen is separated and concentrated due to the difference in permeability between oxygen and nitrogen, and this is used as an inert gas. Therefore, the equipment can be made compact and low-cost, a power source is not required, and approval for high-pressure gas and explosion-proof measures are unnecessary.

According to the jet soldering method of the fourth aspect, since the jet solder at the most oxidizable position is sandwiched and covered with the inert gas, the oxidation of the solder can be suppressed very efficiently with a small amount of the inert gas. You can As a result, it is possible to reduce the amount of solder scraps with a small-sized device, and it is possible to further reduce the problems caused by the above-mentioned solder scraps.

According to the jet soldering method of the present invention, not only the jet solder falling on the molten solder liquid surface but also the movable portion of the device for generating the solder jet, such as the shaft of the jet sending device, Since the inert gas is also supplied to the part in contact with the molten solder liquid surface in the solder bath, that is, the position where other air is easily entrained, the solder oxidation can be suppressed more efficiently with a small amount of inert gas. Is possible.

[0018]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 1 and 2 are a perspective view and an exploded perspective view, respectively, showing a jet soldering device according to a first embodiment of the present invention. In these figures, the inside of the solder bath 1 for containing the molten solder 2 is divided into two layers, an upper layer and a lower layer, by a partition plate 3. The upper portion of the solder bath 1 has a longitudinal slot 5 for ejecting a solder jet upward, and a solder jet nozzle 4 protruding upward from the surface of the molten solder 2 in the longitudinal direction. It is provided on one side. A hole is opened in the partition plate 3 in which the slot 5 is located so that the upper and lower layers communicate with each other.

As shown in FIG. 3, one embodiment of the solder jet nozzle 4 is a nozzle body 6 having a slot 5 in the center and a nozzle main body 6 which is connected to the upper portion of the nozzle body 6 and which sandwiches the slot 5 in a substantially opposite direction. It has a pair of horizontally extending sleeve portions 7 and 8. Each free end of these sleeves 7 and 8 has a slot 5
The jet solder S from the solder passes through the upper surfaces of the sleeves 7 and 8 and the solder bath 1
So that it can naturally fall onto the molten solder surface inside
It is bent so as to face the molten solder liquid surface, and is formed so as to have slight gaps 9 and 10 with the molten solder liquid surface.

Further, the covers 11 and 1 are provided with optimum gaps so as to face the pair of sleeve portions 7 and 8, respectively.
2 is attached to the solder bath 1. Each of the covers 11 and 12 is a bracket 11 fixed to the side wall of the solder bath 1.
a and 12a and slide covers 11b and 12b attached to the brackets 11a and 12a so as to be slidable toward the pair of sleeves 7 and 8, and cover a part of the solder bath 1 on the side wall side. ing. These slide covers 11b and 12b are provided with screw fixing slots 1 provided therein.
It is possible to adjust the slide by 3,14.
The gap between the sleeve portions 7 and 8 and the slide covers 11b and 12b is as narrow as possible and does not interfere with the flow of the jet solder S, that is, the jet solder S passes over the sleeve portions 7 and 8 and the solder bath. It is adjusted appropriately so that it can naturally fall on the molten solder surface in 1. The free ends of the slide covers 11b and 12b are bent toward the liquid surface of the molten solder in the same manner as the free ends of the sleeves 7 and 8, and a slight gap 15 or 16 is formed between the free ends of the liquid and the molten solder. Is formed to have.

At the upper surface position of the solder jet S formed on the upper portion of the slot 5 of the solder jet nozzle 4, a conveyer C for carrying an electronic component P such as a printed circuit board is arranged. When the component P passes through this position, a predetermined portion of the electronic component P to be soldered comes into contact with the solder jet S and is automatically soldered.

Gas supply holes 17, 18, 19, 2 to which a gas supply tube (not shown) is connected are provided at the bottoms of the pair of sleeves 7, 8 and the slide covers 11b, 12b.
0 are provided respectively, and an inert gas such as nitrogen gas can be supplied into the sleeve and the slide cover. That is, the gas supply holes 17 and 1
The inert gas supplied from 9, 18 and 20 passes through the gaps 9 and 15, 10 and 16 respectively, so that the inert gas drops into the molten solder in the solder bath 1 through the upper surfaces of the sleeve portions 7 and 8. It is possible to cover so as to sandwich S.

On the side of the solder bath 1 facing the solder jet nozzle 4 in the longitudinal direction, a jet delivery device 21 for forming a solder jet and sending the jet to the solder jet nozzle 4 is provided. As shown in FIG. 4, the jet flow delivery device 21 includes a rotatable shaft 22 connected to a motor (not shown), a support portion 23, an impeller 24 fixed to a tip portion of the shaft 22, and And a cover 25. The cover 25 is provided with a gas supply hole 26 to which a gas supply tube (not shown) is connected, so that an inert gas such as nitrogen gas can be supplied into the cover.

A hole is formed in the partition plate 3 at the position where the jet flow delivery device 21 is provided so that the upper and lower layers communicate with each other. The impeller is provided so as to be located in the lower layer portion of the solder bath 1, and its rotation causes the molten solder to be sent out to the slot 5 of the solder jet nozzle 4 through the lower layer portion. The lower portion of the cover 25 is soaked in the molten solder so that nitrogen gas does not leak to the outside of the cover 25. A baffle plate P is provided between the solder jet nozzle 4 of the solder bath 1 and the jet delivery device 21 to prevent solder residue generated around the solder jet nozzle 4 from approaching the jet delivery device 21. ing.

FIG. 5 shows the gas supply holes 17-20 and 26.
1 shows an embodiment of a nitrogen generator for supplying nitrogen gas to the. In FIG. 5, the compressed air introduced into the nitrogen generator as indicated by the arrow passes through the air filter 27 and the mist separator 28 to remove dust, water, etc., and then enters the hollow fiber module 30. This hollow fiber has a property of preferentially permeating oxygen over nitrogen, and due to this property, when passing through the hollow fiber module 30, oxygen is released to the outside of the module, and as a result,
Nitrogen is concentrated and separated in the pressurized state, and is taken out from the module 30 via the pressure gauge 32, the flow meter 33, and the flow rate adjusting valve 34. In this figure, 29 is a regulator and 31 is a thermometer.

The compressed air introduced into the nitrogen generator here is usually compressed air used in the factory, for example, 3 kg / cm ^{2 to} less than 10 kg / cm ² , preferably 5 kg / cm ^{2 to} 9 kg / cm. ^Two compressed air can be used. When such compressed air is introduced into the nitrogen generator shown in FIG. 5, the purity is 95 to 99% (the amount of generation is 20 Nl.
/ Min) or more) of N2 gas, which can be sufficiently used to achieve the object of the present invention. The nitrogen generator as shown in FIG. 5 is much more compact than the conventional one, can keep the cost very low, and does not require high-pressure gas license, explosion-proof measures and power supply.

Next, the operation of the jet soldering apparatus of the first embodiment and the jet soldering method of the present invention will be described. When the impeller 24 of the jet flow delivery device 21 is rotated by the motor, the molten solder 2 in the solder bath 1 is delivered to the solder jet nozzle 4 through the lower layer of the solder bath 1 and, as shown in FIG. Molten solder is jetted upward from the slot 5 of the jet nozzle 4 to form a solder jet S. When the electronic component P is conveyed by the conveyor C and passes through the top of the solder jet S, the portion of the electronic component P to be soldered comes into contact with the top of the solder jet S and soldering is automatically performed. In this way, the electronic components P on the conveyor C are automatically soldered one after another while being conveyed.

Thereafter, the solder jet S flows on the upper surfaces of the sleeve portions 7 and 8 and drops into the molten solder 2 of the solder bath 1 through the gap between the sleeve portions 7 and 8 and the slide covers 11b and 12b. At this time, the lower portions of the sleeves 7 and 8 and the slide covers 11b and 12
The lower part b is filled with nitrogen gas supplied from the gas supply holes 17, 18, 19, and 20. This nitrogen gas forms a gap 9, 10, 15, 1 with the liquid surface of each molten solder.
It is jetted toward the falling solder flow through 6 and is covered so as to sandwich the falling solder flow from both sides. As a result, it is possible to prevent air from being entrained when the solder flow falls on the liquid surface of the molten solder to oxidize the solder by oxygen in the air. The jet soldering apparatus of this embodiment and the jet soldering method of the present invention cover the solder flow falling on the molten solder liquid surface, which is most likely to be oxidized, by sandwiching it with an inert gas such as nitrogen gas, thereby preventing oxidation. However, since the entire solder jet S is not covered with nitrogen gas, the oxidation of the solder can be suppressed very efficiently with a small amount of inert gas, and the solder residue can be reduced with a small device.

Further, the inside of the cover 25 of the jet flow delivery device 21 is filled with the nitrogen gas supplied through the gas supply hole 26, and as a result, the rotating shaft 22 causes the liquid surface of the molten solder 2 in the solder bath 1 to rise. Since the part in contact with, that is, the part that is most likely to be entrained with air is covered with nitrogen gas,
Further, it is possible to efficiently suppress the oxidation of solder with a small amount of inert gas.

It is possible to produce and produce solder residue when soldering is performed without using nitrogen gas and when the jet soldering apparatus and jet soldering method according to the first embodiment are performed under the following conditions. The results of the number of substrates produced are shown in Table 1 and Table 2, respectively. The amount of solder residue in these tables is the total amount of solder residue generated around the solder bath 1 and the jet flow delivery device 21. Supply compressed air pressure: 5.0 kg / cm ² Supply temperature: 31 ° C. Nitrogen gas generation rate: 38 Nl / min O 2 concentration: About 5%

[Table 1]

[Table 2]

As is clear from Tables 1 and 2 above,
According to the jet soldering apparatus and the jet soldering method according to the first embodiment, the amount of solder residue generated is reduced by 60% or more as compared with the case where soldering is performed without using nitrogen gas. Therefore, the waste of solder can be minimized and the work of removing solder residue can be reduced, and the factors that cause heavy metal damage to the operator can be reduced.

Further, the supply compressed air pressure is 3 kg / cm ²
It is changed at less than 10 kg / cm ² to 5 to 1% (5
When nitrogen gas in a pressurized state having an oxygen concentration of 50,000 to 10,000 ppm) was generated and the same experiment was performed, the result comparable to the result in Table 2 above could be obtained. As described above, according to the jet soldering apparatus and method according to the first embodiment, the oxygen concentration is 5 to 1% (50,000 to 50%).
Despite the use of low-purity nitrogen gas (10,000 ppm), the generation of solder residue can be greatly reduced. Therefore, a large nitrogen gas generator is not required, and the generation of solder residue can be reduced very efficiently with extremely simple equipment.

FIG. 6 is a vertical sectional view showing a second embodiment of the solder jet nozzle 4. In this embodiment, an adjusting plate 35 for adjusting the speed of the solder jet is provided at the free end of the sleeve portion 8.
Is provided, which is different from the first embodiment shown in FIG. The adjusting plate 35 is slidably attached to the end of the sleeve 8 so that the height thereof can be finely adjusted.

FIG. 7 is a vertical sectional view showing a third embodiment of the solder jet nozzle 4. This embodiment is different from the first embodiment shown in FIG. 3 in that the sleeve portion 8 is provided with the solder pool 36. However, these FIG.
Also in the second and third embodiments shown in and 7, the function of the nitrogen gas supplied from the gas supply holes 17, 18, 19, 20 in the sleeve portions 7, 8 and the slide covers 11b, 12b is as follows. This is the same as the case of the first embodiment of FIG. That is, it is possible to suppress the oxidation of the solder very efficiently with a small amount of inert gas by sandwiching the solder flow falling on the surface of the molten solder that is most likely to be oxidized with nitrogen gas, and to reduce the solder residue in a small device. To do.

Although the present invention has been described herein based on the preferred embodiments described above, the present invention is not limited to these embodiments, and various modifications can be made. Of course. For example, in the above embodiment, the partition plate 3, the solder jet nozzle 4, the jet flow delivery device 21 and the like are attached to the solder bath 1 to form a two-layer structure, but the partition plate, the solder jet nozzle, the jet flow delivery device and the like are provided. It is also possible to separately provide a duct having a two-layer structure and to immerse the duct in the solder bath 1.

[0036]

As described above in detail, according to the jet soldering apparatus and the jet soldering method of the present invention, the following excellent effects are exhibited. According to the jet soldering device of claim 1, the jet solder jetted from the solder jet nozzle drops on the sleeve portion into the molten solder in the solder bath. The drop jet solder is sandwiched by the inert gas supplied by the inert gas supply means provided in the lower portion and the cover means lower portion. Normally, when the jet solder drops on the molten solder surface,
It is easy for air to be entrapped, and thus the solder is most likely to be oxidized at this time. According to this jet soldering device, since the solder at the most oxidizable position is sandwiched and covered with the inert gas, the oxidation of the solder can be suppressed very efficiently with a small amount of the inert gas. As a result, it is possible to reduce the amount of solder scraps with a small-sized device, and it is possible to further reduce the problems caused by the above-mentioned solder scraps.

According to the jet soldering device of the second aspect, although a low-purity inert gas containing 10,000 to 50,000 ppm of oxygen is used, extremely efficient and sufficient effects can be obtained. It is possible to eliminate the need for a large-sized inert gas generator.

According to the jet soldering device of the third aspect, compressed air is permeated through the hollow fiber membrane, nitrogen is separated and concentrated due to the difference in permeability between oxygen and nitrogen, and this is used as an inert gas. Therefore, the equipment can be compact and low-cost, and the high-pressure gas license and explosion-proof measures are unnecessary.

According to the jet soldering method of the fourth aspect, since the solder in the most oxidizable position is sandwiched and covered with the inert gas, the oxidation of the solder can be suppressed very efficiently with a small amount of the inert gas. it can. As a result, it is possible to reduce the amount of solder scraps with a small-sized device, and it is possible to further reduce the problems caused by the above-mentioned solder scraps.

According to the jet soldering method of the fifth aspect, not only the jet solder falling on the molten solder liquid surface but also the movable portion of the device for generating the solder jet, such as the shaft of the jet sending device, is provided. Since the inert gas is also supplied to the part in contact with the molten solder liquid surface in the solder bath, that is, to the other position where other air is easily entrained, the oxidation of the solder is suppressed more efficiently with a small amount of the inert gas. It becomes possible to do.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a jet soldering device of the present invention.

FIG. 2 is an exploded perspective view of FIG.

FIG. 3 is a vertical cross-sectional view showing a first embodiment of the solder jet nozzle 4.

4 is a perspective view showing an embodiment of the jet flow delivery device 21. FIG.

FIG. 5 is a vertical sectional view showing an embodiment of a nitrogen generator.

FIG. 6 is a vertical cross-sectional view showing a second embodiment of the solder jet nozzle 4.

7 is a vertical sectional view showing a third embodiment of the solder jet nozzle 4. FIG.

[Explanation of symbols]

 1 Solder Tank 2 Molten Solder 3 Partition Plate 4 Solder Jet Nozzle 5 Slot 6 Nozzle Body 7,8 Sleeve 9,10,15,16 Gap 11b, 12b Slide Cover 17,18,19,20,26 Gas Supply Hole 21 Jet Delivery device 22 Shaft 24 Impeller 25 Cover

Claims (5)

[Claims] 1. A solder bath for containing molten solder, a nozzle main body having a slot projecting above the molten solder and ejecting the molten solder in the central portion, and a nozzle body slightly separated from the liquid surface of the molten solder. A solder jet nozzle having a pair of sleeves formed so as to extend from the upper part of the nozzle body toward the liquid surfaces of the molten solder on both sides, and the molten solder is jetted from a slot of the solder jet nozzle, and the jet solder is applied to the sleeve portion. A gap for passing jet solder is formed between the sleeve part and the pump means for forming a solder flow so as to drop into the molten solder in the solder bath from the upper surface of the molten solder liquid surface in the solder bath. A cover means extending toward the liquid surface of the molten solder so as to be slightly separated from the cover, and covering at least a part of the solder bath; An inert gas supply means for releasing an inert gas so as to sandwich the jet solder falling into the molten solder in the solder bath from both sides thereof, and a part of the component to be soldered may come into contact with the jet solder. , A jet soldering device having a conveying means for conveying the component along a predetermined conveying path. 2. The inert gas supply means is 10,000 to 1000.
The jet soldering device according to claim 1, wherein an inert gas containing 50,000 ppm of oxygen is supplied. 3. The inert gas supply means is connected to a nitrogen gas generator for allowing compressed air to permeate the hollow fiber membrane and separating and concentrating nitrogen according to the difference in permeability between oxygen and nitrogen. The jet soldering device according to claim 1. 4. Automatic soldering of a component in which a molten solder is jetted from a nozzle projecting above the molten solder in a solder bath, and the jet solder is carried such that a portion of the component to be soldered is brought into contact with the jetted solder. A method of supplying an inert gas from both sides of a jet solder that falls into the molten solder in a solder bath so as to sandwich the jet solder and suppress the oxidation of the solder due to the drop of the jet solder into the molten solder. A method for soldering by jet flow of parts. 5. The component according to claim 4, wherein the movable part of the device for generating the jet of the molten solder supplies the inert gas also to the part in contact with the liquid surface of the molten solder in the solder bath. Jet soldering method.