JPH0629655A - Soldering equipment - Google Patents

Abstract

PURPOSE:To uniformly keep distribution density of inert gas in a chamber covering a preliminarily heating part and a soldering part. CONSTITUTION:A conveyer 2 for carrying printed boards on which electronic parts are temporally fixed, a preheater 6, and a solder tank 7 are installed in a chamber 1. A plurality of nozzles 8A-8F for supplying inert gas are arranged in order, in the carrying direction of the printed boards in the chamber 1. An inert gas supplying equipment 14 increases or decreases the supply amount of the inert gas from the nozzles 8A-8F, in response to the atmosphere temperature in the chamber 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering device for soldering in a low oxygen state of an inert gas atmosphere, in which a printed circuit board on which electronic parts are temporarily attached is formed in a chamber.

[0002]

2. Description of the Related Art As an example of a conventional soldering apparatus, a non-oxidizing chamber is provided in a chamber that has a soldering section consisting of a preheater and a solder bath with only an inlet section and an outlet section opened.
A soldering device is known in which a non-corrosive gas atmosphere is formed, a printed circuit board is carried into a chamber through an inlet portion and an outlet portion, and soldering is performed in the gas atmosphere (Shokai Sho 56- No. 142869).

Another example of the conventional soldering apparatus is soldering in which a sealing flap, that is, a tunnel section having a shutter mechanism is connected to the inlet and outlet of a chamber forming a gas atmosphere. The device is also known (see JP-A-2-303675).

[0004]

By the way, an atmosphere of an inert gas is formed in a chamber which covers a preheater for preliminarily heat-treating a printed circuit board and a soldering portion for soldering while the printed circuit board is being conveyed, and the chamber is covered with the inert gas atmosphere. When soldering is performed in an oxygen state, the temperature inside the chamber rises due to the influence of the preheater provided in the chamber or the heat of the molten solder in the solder bath.

On the other hand, since the inlet opening and the outlet opening for transporting the printed circuit board are formed at both ends of the chamber, the temperature distribution in the chamber becomes unstable and a thermal convection phenomenon occurs. Therefore, the gas distribution density in the high temperature part in the chamber is diluted, unevenness of the gas distribution density occurs in the low temperature part, and it becomes difficult to maintain a uniform gas distribution in the chamber, resulting in poor soldering accuracy. It is confirmed to bring.

Further, since the inlet opening and the outlet opening of the chamber are formed at the boundary between the outside air and the thermal convection phenomenon, a large amount of gas is consumed due to the leakage of the inert gas in the chamber. was there.

Further, in order to cut off the outside air in the chamber to suppress the gas consumption, in the case where the chamber is connected to the tunnel section equipped with the shutter mechanism, the opening / closing of the shutter mechanism related to the printed board to be conveyed is related. There is a problem in that the operation mechanism is technically complicated and the chamber structure is enlarged.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a soldering device which can maintain the distribution density of an inert gas uniformly.

It is another object of the present invention to provide a soldering device which can suppress the leakage of inert gas by providing a partition in the chamber of the soldering device.

[0010]

SUMMARY OF THE INVENTION A soldering apparatus according to the present invention is at least 3 in the direction of carrying a printed circuit board.
A plurality of inert gas supply nozzles are sequentially arranged in the chamber, and an inert gas supply device is provided to increase or decrease the amount of inert gas supply to each inert gas supply nozzle according to the ambient temperature in the chamber. It is a thing.

Further, in the chamber, partition walls formed in a direction perpendicular to the direction of carrying the printed circuit board are sequentially provided along the direction of carrying the printed circuit board.

[0012]

In the present invention, the supply amount of the inert gas is changed according to the temperature of the atmosphere in the chamber at each of the portions where at least three inert gas supply nozzles are provided in the printed board carrying direction. By increasing or decreasing,
The inside of the chamber is uniformly maintained in a low oxygen state of an inert gas atmosphere.

Further, the partition wall in the chamber makes the distribution density of the inert gas more uniform and suppresses the leakage of the inert gas.

[0014]

1 is a block diagram showing an embodiment of the present invention, FIG.
Shows a plan view of FIG. 1. In these figures, reference numeral 1 denotes a chamber, through which a conveyor 2 as a means for holding and carrying a printed circuit board 5 is provided. Reference numerals 3 and 4 denote an inlet opening and an outlet opening of the chamber 1. In the chamber 1, a preheater 6 that constitutes a preheating portion and a solder bath 7 that constitutes a soldering portion are housed. 8
Reference numerals A to 8F denote inert gas supply nozzles (hereinafter referred to as supply nozzles) sequentially arranged in the longitudinal direction of the chamber 1, and the supply nozzles 8A to 8F are flow rate adjusters 9A, respectively.
~ 9F, stop valve 10A ~ 10F, adjusting valve 1
The inert gas is supplied from the gas supply source 12 via 1A to 11F. Reference numeral 13 is a filter, and 14 is an inert gas supply device including the flow rate adjusters 9A to 9F, stop valves 10A to 10F, adjustment valves 11A to 11F, a gas supply source 12, and a filter 13. Also, 17A to 17F
Is an ejection nozzle described later (shown by a chain line in FIG. 2).

Next, the operation will be described. The printed circuit board 5 is held by the conveyor 2 and conveyed in the direction of arrow A,
The preheater 6 in the low oxygen state of the inert gas atmosphere in the chamber 1 heats up to a temperature near the temperature at which the solder melts, and then solders in the solder bath 7.

A preheater 6 and a solder bath 7 are housed in the chamber 1 which has been filled with an inert gas, and the temperature inside the chamber 1 is raised by heating by the preheater 6 and heat of the solder melt in the solder bath 7. To be done.

On the other hand, an inlet side opening 3 and an outlet side opening 4 which penetrate the conveyor 2 of the printed circuit board 5 are formed at both ends of the chamber 1, and the inside of the chamber 1 near these openings 3 and 4 is Since the temperature is lower than that in the central portion, a thermal convection phenomenon occurs in the chamber 1, and the distribution density of the inert gas is diluted toward the higher temperature portion, and the gas distribution density in the chamber 1 becomes less. Create a uniform situation.

Further, at least three or more supply nozzles 8A to 8F are sequentially arranged in the chamber 1 in the conveying direction of the printed circuit board 5 (direction of arrow A), that is, in the longitudinal direction of the chamber 1. High temperature part of the ambient temperature,
The supply amount of the inert gas to the supply nozzles 8A to 8F corresponding to the low temperature part is adjusted by the flow rate adjusters 9A to 9F and the stop valve 10A of the inert gas from the gas supply source 12, respectively.
It is possible to increase or decrease by adjusting 10 to 10F and adjusting valves 11A to 11F.

The inlet opening 3 and the outlet opening 4 of the chamber 1 are narrowed so as not to come into contact with the printed circuit board 5, so that a further inert gas sealing effect can be obtained.

FIG. 3 is a diagram showing the supply amount of inert gas and the ambient temperature distribution formed in the chamber 1 shown in FIG.
It is shown that the temperature is highest near the supply nozzles 8B and 8C. Therefore, the supply nozzle 8B
And since the gas distribution density around 8C is low,
The amount of gas supplied to the supply nozzles 8B and 8C in this portion is adjusted so as to be ejected to the maximum, and the locations of the other supply nozzles 8A and 8D to 8F are all reduced according to the fixed price of the atmospheric temperature in the chamber 1. Let me supply. As a result, it was confirmed that the gas distribution density in the chamber 1 was made uniform.

The inert gas supplied from the supply nozzles 8A to 8F into the chamber 1 is supplied to the supply nozzles 8A to 8F.
It may be directly supplied from a plurality of ejection holes, or as shown in FIGS. 2 and 4, the longitudinal direction thereof is formed in a direction perpendicular to the conveying direction of the printed circuit board 5 (direction of arrow A in FIG. 2). The ejection nozzles 17A to 17E (FIG.
May be attached to each of the supply nozzles 8A to 8F and supplied.

FIG. 5 is a constitutional view showing another embodiment of the present invention, in which the same reference numerals as those in FIG. 1 designate the same parts, and a plurality of partition walls 15A to 15E are arranged in the longitudinal direction in the chamber 1 to form a printed board 5.
Are formed in a direction perpendicular to the carrying direction of the printed circuit board 5 and are sequentially arranged along the carrying direction of the printed circuit board 5. Partition walls 15A to 15
Needless to say, E is in the form of a sheet formed of, for example, heat-resistant rubber or the like, and is provided at least to the extent that it does not hinder the conveyance of the printed circuit board 5.

The partition walls 15A to 15E in the chamber 1 are adjacent to each other, that is, partition walls 15A and 15B, 15B and 15C ,.
Since a plurality of independent space portions are formed between 15D and 15E, the thermal convection phenomenon generated in the chamber 1 is dispersedly generated to reduce the size, and the inert gas distribution density is made uniform, and at the same time, the chamber 1 is formed. It has the effect of suppressing gas leakage inside and minimizing gas consumption.

Further, since the chamber 1 is filled with an inert gas and is in a low oxygen state, it is effective for preventing the soldered portion of the printed circuit board 5 and the solder melt from being oxidized, and the solder having a relatively high accuracy. It is attached. In addition, when soldering in an oxygen-free, low-oxygen atmosphere, it is possible to use flux with a low residue component of flux processing, which is indispensable for soldering processing, and non-flux processing. It is relatively easy and easy to clean the printed circuit board, and no cleaning is required.

When a curtain (not shown) made of an inert gas is provided at the inlet opening 3 and the outlet opening 4 of the chamber 1, a further sealing effect can be obtained.

The soldering apparatus in the above embodiment has been described based on the immersion soldering apparatus in the inert gas atmosphere by the solder bath 7. However, the furnace structure such as hot air reflow soldering method in the same inert gas atmosphere is used. It is needless to say that the same effect can be obtained by applying the chamber 1 of the present invention to the reflow soldering method according to 1.

[0027]

As described above, according to the present invention, at least three or more inert gas supply nozzles are sequentially arranged in the chamber in the conveying direction of the printed circuit board, so that the ambient temperature in the chamber can be adjusted according to the high or low. In addition, since an inert gas supply device that increases or decreases the amount of inert gas supplied to each inert gas supply nozzle is provided, the inert gas distribution density in the chamber is always maintained at a uniform level. Good soldering can be performed.

In addition, since the partition walls formed in the chamber at right angles to the direction in which the printed circuit board is carried are sequentially provided along the direction in which the printed circuit board is carried, the distribution density of the inert gas in the chamber is made more uniform. In addition to that, it has an effect that the leakage of the inert gas in the chamber can be suppressed to the minimum.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a diagram showing a supply amount of an inert gas formed in a chamber and an ambient temperature distribution.

FIG. 4 is an enlarged cross-sectional view showing a jet nozzle.

FIG. 5 is a configuration diagram showing another embodiment of the present invention.

[Explanation of Codes] 1 Chamber 2 Conveyor 5 Printed Circuit Board 6 Preheater 7 Solder Tank 8A to 8F Inert Gas Supply Nozzle 14 Inert Gas Supply Device 15A to 15E Partition Wall

Claims (2)

[Claims] 1. A conveyance means for a printed circuit board on which electronic components are temporarily attached, a preheating section, and a soldering section are provided in a chamber, and the chamber is kept in a low oxygen state in an inert gas atmosphere. In a soldering device for soldering to the printed circuit board, at least three or more inert gas supply nozzles are sequentially arranged in the chamber in the conveying direction of the printed circuit board to increase or decrease the ambient temperature in the chamber. A soldering device comprising an inert gas supply device for increasing or decreasing the supply amount of the inert gas to each of the inert gas supply nozzles. 2. The soldering apparatus according to claim 1, wherein partition walls formed in the chamber in a direction perpendicular to the direction of carrying the printed circuit board are sequentially provided along the direction of carrying the printed circuit board.