JPH071113A - Soldering apparatus in low oxygen atmosphere - Google Patents

Abstract

PURPOSE:To provide a soldering apparatus in a low oxygen atmosphere, in which the inner part in a chamber can be held in a stable low oxygen condition. CONSTITUTION:In the chamber 2, a conveyor 4 for work 3 and a soldering vessel 8 are arranged. Further, partition plates 9 for restraining the flow-out and the convection of inert gas in the chamber 2 are arranged at the necessary interval in a carrying direction of the work 3. Further, inert gas supplying nozzles 10 are arranged between the partition plates 9 at the position, in which the work 3 completes the soldering in the soldering vessel 8, to form the inert gas supplying chambers 13 and by stably supplying the inert gas, the low oxygen atmosphere is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low oxygen atmosphere soldering apparatus for soldering a work in a chamber in a low oxygen state by an inert gas.

[0002]

2. Description of the Related Art A conventional low oxygen atmosphere soldering apparatus is
For example, by gently injecting warmed inert gas from the top of a container that has a discharge port below, the inert gas is filled from the top of the container. Cold air is discharged from the discharge port below. The container is not completely airtight, does not require a vacuum device, and can create an inert atmosphere within the container that does not oxidize the metal. It allows objects (work pieces such as printed circuit boards) to be taken in and out without disturbing the inert atmosphere. It utilizes the difference in specific gravity between warmed inert gas and cold ambient air to In order to prevent the mixture of oxygen in the air, a stable inert atmosphere is created in the processing container (JP-A-60-
No. 124464).

[0003]

By the way, in the conventional apparatus having the above-described structure, the height difference between the upper portion of the container and the lower discharge port must be sufficiently secured and the work passage must be lengthened. The required low oxygen atmosphere cannot be obtained. Also, it is designed to gently inject the inert gas,
Initially, it is necessary to discharge the air of 1 atm filled in the container and to inject an inert gas having a pressure of 1 atm or more in order to prevent the air from flowing backward from the discharge port and entering. Therefore, the mixture of inert gas and air in the container makes the low oxygen atmosphere unstable, and in order to eliminate this, the amount of inert gas used increases and the size of the device becomes large. There was a point.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a low oxygen atmosphere soldering apparatus capable of maintaining a stable low oxygen state in the chamber.

[0005]

A low oxygen atmosphere soldering apparatus according to the present invention is an inert gas supply nozzle for supplying an inert gas to a position rearward from a position where soldering of a work is completed at a soldering portion. Is provided.

Further, the inert gas supply nozzle is provided between the partition plates to form the inert gas supply chamber.

Further, the ejection port for ejecting the inert gas from the inert gas supply nozzle is formed at a position facing the bottom of the inert gas supply chamber.

Further, a rectifying plate for letting out the inert gas flowing out of the inert gas supply chamber in the direction opposite to the conveying direction of the work is provided on the partition plate forming the inert gas supply chamber.

[0009]

In the present invention, since the gas supply nozzle is provided at a position rearward from the position where the soldering of the work is completed, the inert gas is stably supplied to the solder bath. Convection of an inert gas in the part is prevented and the low oxygen atmosphere is stabilized.

Since the inert gas supply nozzle is provided between the partition plates to form the inert gas supply chamber, the flow of the inert gas is stabilized, so that the soldered portion is Supply a stable inert gas.

By jetting the inert gas toward the bottom of the inert gas supply chamber, the concentration of the inert gas flowing out of the inert gas supply chamber is made uniform.

Further, since the partition plate is provided with the straightening plate, the inert gas supplied from the inert gas supply chamber forms a laminar flow parallel to the conveyor and flows in the direction opposite to the conveying direction of the work. Suppress the outflow of inert gas from the outlet.

[0013]

FIG. 1 is a side sectional view showing an embodiment of the present invention.
Reference numeral 1 denotes a main part of a low oxygen atmosphere soldering apparatus (hereinafter referred to as a soldering apparatus). A chamber 2 is filled with an inert gas and maintains a stable low oxygen atmosphere by a pressure higher than the pressure of the outside air. A conveyer 4 for holding a work 3 such as a printed circuit board and conveying it in the direction of arrow A is provided through the chamber 2 and has an inlet 5 and an outlet 6. Further, inside the chamber 2, a preheater 7 that constitutes a preheating unit and a solder bath 8 that constitutes a soldering unit are provided, and a solder melt (not shown) in the solder bath 8 The liquid surface is sealed by the chamber 2 and kept in a low oxygen atmosphere. Reference numeral 9 denotes a plurality of partition plates provided inside the chamber 2, which are sequentially provided at required intervals in the transport direction of the work 3.
The passage through which is carried is narrowed to prevent the inert gas in the chamber 2 from flowing out from the inlet portion 5 and the outlet portion 6. 1
Reference numeral 0 denotes an inert gas supply nozzle, which is provided between the partition plate 9 and the partition plate 9 at a position rearward from the position where the soldering of the work 3 is completed, and is opposed to above and below the conveyor 4. Inert gas supply chambers 13 having a U-shaped cross section are formed so as to face each other, and are connected to an inert gas supply source 12 via a pipe 11. Further, the longitudinal direction of the inert gas supply nozzle 10 is arranged in a direction perpendicular to the conveying direction (arrow A direction) of the work 3. In addition, 14 is a current plate and 16 is an air supply nozzle.

FIG. 2 is an enlarged sectional view showing the details of the inert gas supply chamber 13 of FIG. 1, and the same reference numerals as those in FIG. The active gas is obliquely upward or downward in the conveying direction of the work 3 (arrow A direction), that is, the inert gas supply chamber 1
3 is formed so as to be ejected toward the upper bottom portion 13a or the lower bottom portion 13b. Reference numeral 14 is a rectifying plate provided on the partition plate 9 forming the inert gas supply chamber 13, and the inert gas is directed toward the solder bath 8 and the preheater 7 by an arrow B.
A laminar flow as shown by is formed, and more inert gas is supplied in the direction opposite to the conveying direction of the work 3 (direction of arrow A). The straightening vane 14 is not limited to the shape shown by the solid line, and may have the shape shown by the broken line. In addition, the arrows in the inert gas supply chamber 13 and the partition plate 9 shown in FIG. 2 indicate the flow state of the inert gas.

FIG. 3 is an enlarged sectional view showing the details of the inert gas supply nozzle 10, and the same reference numerals as those in FIG. 1 indicate the same parts.

The inert gas supply nozzle 10 is shown in FIG.
In the above, only the side away from the solder bath 8, that is, the outlet 6 side may be used.

In FIG. 1, reference numeral 16 is an air supply nozzle for ejecting pressurized air, the structure of which is the same as that of the inert gas supply nozzle 10, and the inert gas flowing out from the inert gas supply chamber 13 is at the outlet portion. It is prevented from flowing in the direction of 6 and flowing out.

In FIG. 1, I is the first zone of the low-oxygen atmosphere soldering apparatus 1, which extends from the inlet portion 5 to the rear end of the preheater 7 with respect to the conveying direction of the work 3 (direction of arrow A). Indicates the range of. II is the second zone, and indicates the range in which the preheater 7 and the solder bath 8 are installed. III is a third zone, and shows a range in which the inert gas is supplied from the inert gas supply chamber 13. IV is the fourth zone, indicated by arrow A
The range from the front end of the inert gas supply chamber 13 to the outlet 6 is shown with respect to the direction.

Next, the operation will be described. The work 3 is held by the conveyor 4 and conveyed in the direction of arrow A, preheated by the preheater 7 in the low oxygen atmosphere of the inert gas in the chamber 2, and then soldered in the solder bath 8.

On the other hand, since the pressure of the inert gas in the chamber 2 is higher than that of the outside air, in the first zone I, the inert gas flowing from the second zone II by the partition plate 9 is introduced. 5 and the outside air from flowing in from the inlet portion 5 are suppressed.

Next, in the second zone II, the third zone
Since the inert gas flowing as a laminar flow from the zone III of FIG. 2 is heated by the heat of the pre-heater 7 and the solder bath 8 and is weakened by the partition plate 9, a stable low oxygen atmosphere can be maintained. it can.

Next, in the third zone III, mainly from the inert gas supply chamber 13 to the second zone II, in order to maintain a stable low oxygen atmosphere in the second zone II.
Supplying inert gas to II. Although part of the inert gas also flows to the outlet portion 6, most of the inert gas is provided in the second zone II by providing the partition plate 9 with the straightening vane 14.
Can flow in the direction of, and an inert gas can be formed in a laminar flow.

Next, in the fourth zone IV, the air is jetted from the air supply nozzle 16 to generate the third zone II.
The inert gas supplied from the inert gas supply chamber 13 of I is prevented from flowing out from the outlet portion 6, and the inert gas is supplied to the second
To facilitate sending to Zone II.

As described above, since the inert gas supplied from the inert gas supply chamber 13 stays in the second and third zones II and III, the supply amount of the inert gas can be reduced and the fourth gas can be supplied. The range of the low oxygen atmosphere in the second zone II can be moved forward and backward in the transport direction (direction of arrow A) of the work 3 by adjusting the amount of air supplied from the zone IV.

FIG. 4 is a view showing an example in which a rotatable rectifying plate 15 is attached to the inert gas supply chamber 13, the same reference numerals as those in FIG. 2 indicate the same parts, and the inert gas flowing out from the inert gas supply chamber 13 is shown. The direction of the active gas can be changed arbitrarily.

FIG. 5 is a diagram showing the concentration distribution of the inert gas supplied into the chamber 2. Zones I to IV show the same positions as in FIG. 1, and the first zone I to the fourth zone IV are shown. The oxygen concentration up to the first half is low in units of ppm, especially in the portion corresponding to the soldering part of the second zone II and the third zone III.
Is very low. Further, from the latter half of the fourth zone IV, the oxygen concentration in the portion of the outlet portion 6 sharply rises and becomes a unit of%, and at the outlet portion 6, the oxygen concentration in the air (about 20%
%).

[0027]

As described above, according to the present invention, since the inert gas supply nozzle for supplying the inert gas is provided at the position rearward from the position where the soldering of the work is completed at the soldering portion, the chamber is provided. The low oxygen atmosphere in the inner soldering part is stabilized, and the quality of the work by soldering is improved.

Further, since the inert gas supply chamber is formed by providing the inert gas supply nozzle between the partition plates, it is possible to supply the inert gas with a stable flow.

Further, since the ejection port for ejecting the inert gas from the inert gas supply nozzle is formed at the position toward the bottom of the inert gas supply chamber, the concentration of the inert gas becomes uniform.

Further, since the flow regulating plate for flowing out the inert gas flowing out from the inert gas supply chamber in the direction opposite to the conveying direction of the work is formed on the partition plate of the inert gas supply chamber, A laminar flow of the outflowing inert gas is formed, a turbulent flow of the inert gas can be prevented, the outflow of the inert gas can be suppressed, and there are various advantages such as being economical.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing details of an inert gas supply chamber in FIG.

FIG. 3 is an enlarged cross-sectional view showing details of an inert gas supply nozzle.

FIG. 4 is an enlarged cross-sectional view showing an example in which a rotatable straightening plate is attached to the inert gas supply chamber.

FIG. 5 is a diagram showing a concentration distribution of an inert gas supplied into the chamber.

[Explanation of symbols]

 1 Low Oxygen Atmosphere Soldering Device 2 Chamber 3 Work 4 Conveyor 5 Inlet 6 Outlet 7 Preheater 8 Solder Tank 9 Partition Plate 10 Inert Gas Supply Nozzle 10a Jet 12 Inert Gas Supply Chamber 13 Inert Gas Supply Chamber 14 Current plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahito Nozue 1-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (72) Kimihiko Nakamura 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (72) Inventor Toshikazu Yasuoka 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (4)

[Claims] 1. A chamber is provided with a conveyor for conveying a work and a soldering section, and an inlet section through which the conveyor penetrates into the chamber for suppressing outflow and turbulent flow of an inert gas in the chamber. And a plurality of partition plates for narrowing the outlet portion are sequentially provided at a predetermined interval in the transport direction of the work, and the work is soldered to the work in a low oxygen atmosphere held by an inert gas. In a low-oxygen atmosphere soldering device for performing soldering, an inert gas supply nozzle for supplying the inert gas is provided at a position rearward from a position where the soldering of the work ends in the soldering portion. Low oxygen atmosphere soldering equipment. 2. The low oxygen atmosphere soldering device according to claim 1, wherein the inert gas supply nozzle is provided between the partition plates to form an inert gas supply chamber. 3. The low oxygen atmosphere solder according to claim 2, wherein an ejection port for ejecting the inert gas from the inert gas supply nozzle is formed at a position facing the bottom of the inert gas supply chamber. Attachment device 4. The partition plate is provided with a rectifying plate for allowing the inert gas flowing out of the inert gas supply chamber to flow out in a direction opposite to the direction in which the work is conveyed.
The low-oxygen atmosphere soldering device described in.