JPH09237964A - Nitrogen-gas sealed soldering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nitrogen-gas sealed soldering device, wherein the increase in oxygen concentration is suppressed to the minimum degree, the used amount of nitrogen gas can be made less, the mechanism is simple and the compact configuration can be achieved, by providing the inserting/ejecting port of a substrate at one place, and providing a shielding means at this inserting/ejecting port. SOLUTION: A carrier rail 4 and nitrogen-gas injection nozzles 8 are attached at the upper part of a jet soldering tank 1. A carrier is attached to the carrier rail 4. A main cover 10, which covers the solder tank 1, the carrier rail 4 and the nitrogen-gas injection nozzles 8, is attached. Thus, a soldering part A is constituted. An opening part 12, which becomes the inserting/ejecting port of the carrier, is formed at the front part of the main cover 10. A shielding means C, which shields the opening part 12, is attached. The shielding means C is constituted of a curtain part 20 and shutter part 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitrogen gas-filled soldering device, and more particularly to a nitrogen gas-filled soldering device for soldering with a jet nozzle of a jet solder bath while jetting nitrogen gas. is there.

[0002]

2. Description of the Related Art FIG. 8A shows an example of a conventional nitrogen gas-filled solder dip device. A pre-heater section 41 and a jet-type solder bath 42 are arranged along the lower side of the board-transporting conveyor 40, and a hood or chamber 44 is attached so as to cover the pre-heater section 41 and the jet-type solder bath 42. The hood or chamber 44 has a tunnel structure, and an injection nozzle 45 made of a pipe with small holes as shown in FIG. 8B is arranged in the hood or chamber 44 to supply nitrogen gas. An entrance shutter 46 and an exit shutter 47 are provided on the entrance and exit sides of the substrate of the hood or chamber 44 to prevent the oxygen concentration from rising when the substrate enters and exits. In order to maintain the low oxygen concentration, in addition to the shutters 46 and 47 as shown in the figure, a curtain is provided, a labyrinth structure is used, and air, nitrogen gas, etc. are made to flow through the opening of the hood or the chamber 44. I am using.

[0003]

However, in such a conventional apparatus, since the substrate inlet and outlet are provided at two positions on both sides of the hood or chamber 44,
It was unavoidable that oxygen entered the hood or chamber 44 when the substrate entered and discharged, and the oxygen concentration greatly increased. FIG. 9 is a graph showing the relationship between the nitrogen gas supply amount and the oxygen concentration in the solder bath in the conventional device. As is clear from FIG. 9, the oxygen concentration is about 0.1% at 300 liters / minute of nitrogen gas and 0.3% at 200 liters / minute of nitrogen gas.
The maximum capacity value is to maintain about 1% at about 130 liters / minute of nitrogen gas, and it has been difficult to achieve a low oxygen concentration below this value.

When the oxygen concentration rises, the copper foil pattern of the substrate and the solder oxidize, which not only deteriorates the quality of soldering, but also increases the generation of oxides called dross, increasing the amount of solder used. There is. To maintain a low oxygen concentration, various measures such as those mentioned above have been taken, but all of them have complicated mechanisms and are expensive equipment. Especially, the chamber type has a structure that covers the preheater and the solder bath. Therefore, there is a problem in that the length of the chamber becomes 2 to 3 m, the apparatus becomes large, and the maintainability deteriorates. The present invention has been made by paying attention to the above-mentioned points, and by providing a substrate entrance / exit opening at one location and providing a shielding means at this entrance / exit opening, an increase in oxygen concentration is suppressed to a minimum. An object of the present invention is to provide a nitrogen gas-filled soldering device that can reduce the amount of nitrogen gas used and can be downsized with a simple mechanism.

[0005]

In order to achieve the above object, the present invention comprises a jet type solder bath and a transfer means arranged above it, and solders a substrate transferred by the transfer means in a nitrogen atmosphere. An apparatus for performing a soldering part composed of a main cover for covering the jet type solder bath, the conveying means and the nitrogen gas injection nozzle, and a soldering part formed only on the front part of the main cover. And the shielding means which is provided at the entrance and the exit and is opened when the carrier passes.

In the present invention, for example, the carrying means includes a carrier that moves along the carrying path, and the carrier carrying the board enters the soldering part in the main cover from the shutter part and the curtain part of the entrance / exit opening. Then, the board is preheated in the soldering section and then soldered, and when the soldering is completed, the carrier retracts and enters and is discharged from the discharge port.
In this case, it is also possible to adopt a method in which the board is directly conveyed by a conveyor provided with supporting pieces for supporting both sides of the board to be soldered. When shortening the time of the preheating step, the preheating can be carried out by carrying the preheating step to the preheater section at the rear of the main cover. 1 of the main cover
It has a bottom structure with an entrance / exhaust port formed at the location and a closed rear part, and the entrance / exit port is provided with a shielding unit consisting of a shutter part and a curtain part. Suppressed to.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings. FIG. 1 is a side view of the entire nitrogen gas filled soldering device according to one embodiment, FIG. 2 is a cross-sectional view thereof, and FIG. 3 is a schematic external perspective view of an upper cover portion.
1 to 3, molten solder is filled in the jet-type solder bath 1, a 1-wave jet nozzle 2 and a 2-wave jet nozzle 3 are installed in the jet-type solder bath 1, and the nozzle 2, A dross storage portion 9 is provided near the upper portion of 3.
A carrier rail 4 (corresponding to a carrier path) is arranged above the jet solder bath 1, and a carrier 5 is mounted on the carrier rail 4.
Is attached, and in the embodiment, the carrier rail 4 and the carrier 5 are attached.
The transport means is constituted by. The board 6 to be soldered is supported by sandwiching both sides of the support piece 7 of the carrier 5.

At the upper part of the jet type solder bath 1, a conical nitrogen gas jet nozzle 8 is arranged so as to surround the jet nozzles 2 and 3. A main cover 10 that covers the jet type solder bath 1, the transfer rail 4 and the nitrogen gas jet nozzle 8 is attached to the upper portion of the jet type solder bath 1 to form a soldering portion A. The main cover 10 is provided with an opening / closing lid 11 for inspection on the upper part, an opening 12 for forming an inlet / outlet of the carrier 5 is formed in the front part, and an opening 13 for communicating with a preheater part B described later is formed in the rear part. It is a box shape with a downward opening formed with. The right side wall 10a of the main cover 10 shown in FIGS. 2 and 3 is fixed on the jet solder bath 1, and
The lower part of b is in the molten solder of the jet type solder bath 1.

A preheater mounting plate 14 (see FIG. 1) is mounted on the rear portion of the jet type solder bath 1, and a preheater 15 located below the transport rail 4 is mounted on the preheater mounting plate 14. A rear cover 16 is attached to a rear portion of the main cover 10, and an opening 17 (see FIG. 3) on the front surface of the rear cover 16 communicates with the opening 13 of the main cover 10 and covers an upper portion of the preheater 15. The rear rail 16 covers the transport rail 4 and the preheater 15 to form a preheater section B. A lower cover 18 is attached to the front part of the jet solder bath 1, and a shielding means C for shielding the opening 12 (entrance / exhaust port) of the main cover 10 is attached to the lower cover 18. The shielding means C is composed of a curtain portion 20 and a shutter portion 27.

As shown in FIG. 4, the curtain portion 20 is composed of a curtain case 21 and a curtain 22. The curtain case 21 has openings 23, 24 in front and back thereof, leaving an upper surface portion 21a, a side surface portion 21b and the like. The side surface portion 21b is mounted on the lower cover 18. In FIG. 4, the curtain 22 is formed of a heat-resistant flexible sheet such as a glass fiber reinforced Teflon sheet, and the front and rear hanging portions 22b hang from the top plate portion 22a.
The slit 22d is formed in 22c. The top plate portion 22 a is sandwiched between the upper surface portion 21 a of the curtain case 21 and the pressing metal fitting 25, and is fixed by the set screw 26.

As shown in FIGS. 5 and 6, the shutter portion 27 is provided with a shutter case 28 attached to the front portion of the curtain case 21, and the shutter case 28 is provided with a shutter mechanism. The shutter mechanism includes a shutter plate 30, a roller mechanism 31, and an air cylinder 32. Piston rod 33 of air cylinder 32
The first roller 31a is attached to the shutter case 2
A second roller 31b and a third roller 31c are attached to the roller 8.

A wire 35 is fixed to the shutter plate 30 and the shutter case 28 via a wire fixture 34.
The wire 35 is hung on the rollers 31b and 31c. In the raised state of the piston rod 33, the shutter 30 descends vertically due to its gravity as shown in FIG. 6, and closes the opening 36 communicating with the curtain portion 20. When the piston rod 33 is lowered, the wire 35 is pulled by the first roller 31a, the shutter 30 becomes horizontal, and the opening 36 is opened. In FIG. 1, in front of the shutter portion 27, a fluxer 37 that performs flux processing on the substrate is installed below the transport rail 4.

The operation will be described below based on the above configuration. The substrate 6 is mounted on the carrier 5 in front of the fluxer 37.
Set and turn on the start button of the device, the valve from the nitrogen gas generator to the injection nozzle 8 opens, and at the same time, the shutter plate 30 rises and the carrier 5 moves in the approach direction (right direction in FIG. 1). Then, while pushing up the curtain 22, the curtain 22 enters the main cover 10 and stops at the soldering portion A above the jet solder bath 1. The shutter plate 30 is lowered immediately after the carrier 5 has passed therethrough to close the opening 36, and the curtain 22 is also lowered by its own weight, so that the opening 12 is shielded.

The jet flow from the jet nozzles 2 and 3 of the jet type solder bath 1 is lower than that during soldering, and the substrate 6 is preheated by the heat of the solder bath 1 (about 250 degrees). After preheating for a predetermined time, the jets of the jet nozzles 2 and 3 are raised to perform soldering, and the carrier 5 is retracted. The shutter plate 30 is pushed up by the rear surface of the carrier 5 and rises, the carrier 5 passes through as it is and retracts to the original set position, and the soldering process is completed. The above-described operation shows a process for preheating in the solder bath 1. However, if it is desired to shorten the preheating time, the preheater portion C is used. In that case, the carrier 5 is moved straight into the rear cover 16, where preheating is performed, and then the carrier 5 is retracted to the soldering portion A for soldering. However, since the preheating can be performed only by the soldering portion A after a certain time, the preheater portion B does not have to be provided if it is not required to shorten the preheating time.

As described above, according to the present embodiment, the entrance / exhaust port 12 is formed at one position on the front part of the main cover 10 and the rear part is closed, and the entrance / exit port 12 is shuttered. Shielding means C consisting of section 27 and curtain section 20
Since the above is provided, the hermeticity is improved and the oxygen concentration is significantly suppressed. FIG. 7 is a graph showing the results of an experiment on the relationship between the nitrogen gas supply amount and the oxygen concentration in the solder bath in the nitrogen gas-filled soldering device of the present embodiment. As is clear from FIG. 7, when the nitrogen gas supply rate was increased to 100 liters / minute, the oxygen concentration in the solder bath drastically dropped to about 100 ppm and approached 10 ppm at 230 liters / minute. Then, it became clear that the oxygen concentration was significantly suppressed.

As described above, since the low oxygen concentration is maintained and the oxidation of the solder is suppressed, the generation of dross is reduced, the amount of solder used is reduced, and the amount of nitrogen gas used is also reduced. Cost is reduced. Further, the main cover 10, the shutter portion 27, the curtain portion 20, or the preheater portion B, if necessary, is simply assembled from the upper portion of the jet solder bath 1, and the carrier 5 for transporting the substrate 6 is used. Because it is a reciprocating device of
The size can be reduced as a whole, and the inspection can be easily performed from the inspection opening / closing lid 11 or by removing the shutter portion 27 and the curtain portion 20, and the maintainability is improved.

[0017]

As described above in detail, according to the present invention, an apparatus is provided which includes a jet type solder bath and a transfer means arranged above it, and which solders a substrate transferred by the transfer means in a nitrogen atmosphere. A soldering portion formed of a main cover that covers the jet type solder bath, the conveying means, and the nitrogen gas injection nozzle, and is formed only on the front portion of the main cover,
Since the opening portion serving as an entry / exit opening to the soldering portion and the shielding means provided at the entry / exit opening and opened when the carrier passes, the hermeticity of the soldering portion is improved. , Oxygen concentration is greatly suppressed and low oxygen concentration is maintained, so solder oxidation is suppressed, less dross is generated, less solder is used, and less nitrogen gas is used. Therefore, the manufacturing cost is reduced, the configuration is simple, the size can be reduced, and the maintainability is improved.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a nitrogen gas filled soldering device of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is an external perspective view of a cover and a case portion according to the embodiment.

FIG. 4 is an exploded perspective view of the curtain portion according to the embodiment.

FIG. 5 is an exploded perspective view of the shutter unit according to the embodiment.

FIG. 6 is a side view of a shutter portion.

FIG. 7 is a graph of results of experiments on the relationship between the nitrogen gas supply amount and the oxygen concentration in the solder bath of the nitrogen gas-filled soldering device of the present invention.

FIG. 8A is a side view of a conventional soldering device, and FIG.
FIG. 3 is a perspective view of a nitrogen gas injection nozzle.

FIG. 9 is a graph of a result of an experiment on the relationship between the nitrogen gas supply amount and the oxygen concentration in the solder bath of the conventional soldering device.

[Explanation of symbols]

1 ... Jet type solder bath, 4 ... Transport rail, 5 ... Carrier, 6 ... Substrate, 8 ... Injection nozzle, 10 ... Main cover, 12 ... Inlet / outlet port (opening), 15 ... … Preheater, 16 …… Rear cover, 20 …… Curtain part, 2
1 …… Curtain case, 22 …… Curtain, 22d ……
Slit, 27 ... Shutter part, 30 ... Shutter plate,
32 ... Drive mechanism (cylinder), A ... Soldering part, B
…… Pre-heater part, C …… shielding part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Dan Ei 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation

Claims (5)

[Claims] 1. A device comprising a jet-type solder bath and a transfer means disposed above the jet-flow solder bath, for soldering a substrate transferred by the transfer means in a nitrogen atmosphere, wherein the jet-flow solder bath and the transfer means. And a soldering portion formed of a main cover that covers the nitrogen gas injection nozzle, and an opening formed only in the front portion of the main cover, which serves as an inlet and an outlet for the soldering portion, and the inlet and outlet. A nitrogen gas filled soldering device, comprising: a shield provided at an outlet and opened when the carrier passes. 2. The nitrogen gas filled soldering device according to claim 1, wherein the shielding means includes a shutter portion and a curtain portion connected to the shutter portion. 3. The transport means comprises a carrier that moves along a transport path, and in the shutter part, a front part of an oscillating shutter plate is connected to a drive mechanism by a wire, and is opened by the wire when the substrate enters. , The substrate is pushed and released by the carrier when the substrate is discharged.
Alternatively, the nitrogen gas-filled soldering device according to 2 is provided. 4. The curtain part comprises a curtain case having an opening formed therein, and a curtain with a slit made of a heat resistant flexible member mounted in the curtain case. Or the nitrogen gas-filled soldering device according to item 3. 5. A preheater unit, comprising a preheater attached to a rear portion of the jet solder bath, and the preheater portion being configured by sealing the preheater with a rear cover communicating with the soldering portion. 4. The nitrogen gas-filled soldering device according to 4.