JP2001044611A - Soldering equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain soldering equipment wherein a printed wiring board can be rapidly cooled to a desired temperature with cooled air of low cost, oxygen concentration is stable, cost necessary for cooling is low, and function and performance of an electronic component mounted on the printed wiring board are not damaged by cooling, in soldering equipment performing soldering in a chamber body holding an inert gas atmosphere of low oxygen concentration. SOLUTION: A rapid cooling means 7 of a printed wiring board 6 consists of a cool air supplying means 15, which takes in air outside a chamber body 8 and can adjust the flow rate of sending cooled air, a heat dissipating cabinet 17, which blows cool air on a surface 6a to be soldered of the printed wiring board 6 in the chamber member 8 on which surface 6a soldering has been just performed, cools the surface and discharges heated exhaust air, and an air exhausting means, which discharges exhaust air outside the chamber member 8 and can adjust the flow rate of the exhaust air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for soldering a plate-shaped work to be soldered on which a large number of electronic components such as a printed wiring board are mounted.

[0002]

2. Description of the Related Art When an electronic circuit is formed by mounting electronic components on a printed wiring board, soldering is performed. That is, electrical connection and mechanical connection are performed by mounting an electronic component on a printed wiring board and soldering electrodes and lead wires of the component to a circuit pattern of the printed wiring board.

By the way, it is known that by rapidly cooling the solder immediately after soldering, the soldering strength, that is, the mechanical connection strength is increased. For example, Japanese Utility Model Publication No. 45-21716 discloses this. Therefore, the soldering apparatus is configured to provide a cooling step after the soldering step as described in the publication. Accordingly, it is considered that a highly reliable printed wiring board can be manufactured.
The cooling technique described in Japanese Utility Model Publication No. 45-21716 is configured to cool the printed wiring board by blowing air from the fan.

The same applies to a reflow soldering apparatus. For example, Japanese Patent Application Laid-Open No. 60-6270 discloses a configuration in which a cooling fan for cooling a printed wiring board on which reflow soldering has been performed is provided. ing.

[0005] On the other hand, in the soldering process, the solderability is improved by preventing the soldered portion of the printed wiring board and the solder from being oxidized, and the fluidity of the molten solder is improved to form a fine soldered portion. In order to realize so-called micro-soldering for reliable soldering, there is a soldering technique for performing soldering in an inert gas atmosphere having a low oxygen concentration.

A soldering apparatus for performing soldering in an inert gas atmosphere having a low oxygen concentration is configured to supply an inert gas such as a nitrogen gas (N ₂ gas) into a chamber to form an atmosphere having a low oxygen concentration. And a soldering process is performed in the chamber.

In such a soldering apparatus, since the consumption of N ₂ gas is added as running cost, it is necessary that the consumption of N ₂ gas required to maintain the target oxygen concentration be small. . Therefore, a special cooling technique is used so that the atmosphere outside the chamber body does not flow into the chamber body.

For example, the reflow soldering technique disclosed in Japanese Patent Application Laid-Open No. 4-262852 is a technique configured to perform cooling by blowing a cold N ₂ gas supplied from a cylinder onto a printed wiring board after soldering. is there. Further, the technology disclosed in Japanese Patent Application Laid-Open No. 7-202405 is disclosed in Japanese Patent Application Laid-Open No. H07-202405, in which the atmosphere inside a chamber is cooled and filtered to remove flux fumes and the like. This is a technology configured to perform

In the soldering technique disclosed in Japanese Patent Application Laid-Open No. 10-98259, a cooling liquid is sprayed onto a printed wiring board after soldering to cool the printed wiring board, and then hot air is supplied to remove the wet printed wiring board. A drying technique is disclosed.

[0010]

In recent years, electronic equipment having an electronic circuit formed on a printed circuit board has come to be used in all fields of daily life, and has a high level of reliability as equipment supporting life. Is required. Therefore, it is required to further improve the mechanical connection strength of soldering.

[0011] Further, lead mixed into the solder of discarded electronic equipment begins to melt, which poses a problem of contaminating the environment and the human body with lead poison, and lead-less solder has been used. ing. However, this lead-less solder has a problem that a lift-off phenomenon is easily generated in a soldered portion due to solidification segregation of the component. What is the lift-off phenomenon?
This is a defect in soldering in which a partially embrittled region is formed in the soldered portion due to segregation or the like generated in the solder of the soldered portion, and peeling or cracking occurs in the soldered portion. In particular, it is known that it easily occurs in leadless solder containing bismuth.

In order to prevent such a lift-off phenomenon from occurring, the printed wiring board after soldering, that is, the solder in the portion to be soldered is rapidly cooled and segregated with the solidification or solidification of the molten solder. And so on.

However, the cooling technology described in Japanese Utility Model Publication No. 45-21716 and the cooling technology disclosed in Japanese Patent Application Laid-Open No. 60-6270, that is, a cooling technology relying only on mere ventilation, are usually used as a cooling medium. Because the air atmosphere is used as it is, the cooling rate is low,
There is a problem that the degree of cooling cannot be freely adjusted. Further, these techniques have a problem that they cannot be used as they are in a soldering apparatus that supplies an inert gas into a chamber and performs soldering in an inert gas atmosphere having a low oxygen concentration.

That is, supplying air by blowing air to a printed wiring board conveyed in a chamber in which an inert gas atmosphere having a low oxygen concentration is formed causes an extremely large increase in the oxygen concentration. This is because even an inert gas atmosphere having a high concentration cannot be formed. As a result, the soldering quality is significantly impaired.

Further, even if the atmosphere in the chamber is directly blown and supplied to the printed wiring board by blowing it, the atmosphere in the chamber in which the temperature is increased by a high-temperature molten solder or a heater for preliminary heating is sufficient. Not only is it impossible to perform cooling, but also because the air flow in the chamber becomes extremely intense due to this air blowing, a large amount of air enters through the entrance and exit of the printed wiring board, and the oxygen concentration increases. And fluctuate unstablely. As a result, this also significantly impairs the soldering quality.

On the other hand, there is a technique which takes into account special technical matters when soldering in an inert gas atmosphere having a low oxygen concentration as described above.
N ₂ gas of cold N ₂ gas supplied from the gas cylinder as 862 JP technology in configurations allow the blown cooling the printed circuit board after soldering, in order to adjust the amount of cooling or cooling temperature Therefore, there is a problem that the oxygen concentration in the chamber changes. As a result, the soldering quality changes and deteriorates due to the change in the oxygen concentration. Furthermore, in order to increase the cooling amount and lower the cooling temperature, it is necessary to supply a large amount of N ₂ gas, and there is a problem that a large amount of expensive N ₂ gas is consumed and the running cost of soldering is increased. is there.

The technique disclosed in Japanese Patent Application Laid-Open No. 7-202405 is a cooling technique having extremely good power efficiency (or thermal efficiency) when viewed as a whole of a soldering apparatus. In order to further increase the air flow, if the air flow rate of the cooled atmosphere supplied to the printed wiring board is increased, an unstable flow occurs in the atmosphere in the chamber, and the oxygen concentration in the chamber also fluctuates unstable. There is a problem that becomes easy.

In the technique disclosed in Japanese Patent Application Laid-Open No. 10-98259 for cooling by spraying a cooling liquid onto a printed wiring board, the cooling liquid which is sprayed and becomes mist-like and floats is opposite to the surface to be soldered. It adheres to the printed wiring board surface (upper side of the figure), that is, also adheres to the electronic components mounted on that surface, impairs the function of the electronic components or renders them unusable, and produces defective products by soldering. Resulting in. That is,
Many electronic components do not allow droplets to adhere to them (eg, non-molded components such as switches, relays, transformers, coils, etc.), and the soldering technology of the same publication mounts such electronic components. The printed wiring board cannot be soldered and cooled.

As described above, it is remarkably necessary to perform cooling more rapidly than before while performing soldering in an inert gas atmosphere in the chamber body, and to be able to freely adjust the cooling rate and cooling amount. There are difficulties.

An object of the present invention is to provide a soldering apparatus for performing soldering in a chamber holding an inert gas atmosphere having a low oxygen concentration, in which a printed wiring board is cooled to a desired temperature by a cooled atmosphere which is inexpensive. A solder that can be cooled rapidly, has a stable oxygen concentration, and has a low cost for cooling, and does not impair the function and performance of the printed wiring board or the electronic components mounted on the printed circuit board with cooling. An object of the present invention is to realize a mounting device, and as a result, to perform soldering with high connection reliability and to produce a highly reliable printed wiring board.

[0021]

SUMMARY OF THE INVENTION A soldering apparatus of the present invention transports a printed wiring board, which is a work to be soldered, in a chamber which is supplied with an inert gas and holds an atmosphere of an inert gas having a low oxygen concentration. In a soldering apparatus in which the surface to be soldered is brought into contact with molten solder by molten solder supply means and soldered while being conveyed by means, the printed wiring board after soldering, It is characterized in that the work to be soldered is configured to be rapidly cooled before the solder in the soldered portion is completely solidified.

(1) A cool air supply means comprising a cooling means for taking in the air outside the chamber body to cool and generate cool air, and a blowing means capable of adjusting a flow rate of the cool air cooled by the cooling means, and the cold air. A cool air port housing that blows out the cold air supplied from the supply means toward the printed wiring board to which the molten solder is supplied from the air outlet, and the hot air that cools the printed wiring board and collects the heated hot air from the air outlet. A heat-recovery port housing formed of a heat-recovery port casing for discharging, and a heat-recovery port casing forming a heat-recovery port by forming a discharge port of the heat-discharge port casing around a side periphery of a blower port of the cold-air port casing; A chiller for the printed wiring board is constituted by an exhauster capable of adjusting an exhaust air flow rate for discharging the exhaust air from the heat removal port housing to the atmosphere outside the chamber body. Inside the chamber body, The ablative heat port of ablative thermal port housing facing the surface to be soldered of the printed circuit board configured to provide.

With this arrangement, at the heat-removing port of the heat-removing port housing of the quenching means, the cooled air outside the chamber body blown out of the cold-air port casing then immediately flows to the exhaust port of the heat-removing port housing, and A mountain-like cold airflow with a slightly raised state is formed at the heat removal port of the housing. Therefore, disturbances such as supply of a large amount of air or generation of an unstable atmosphere flow are extremely small to the low-oxygen-concentration inert gas atmosphere held in the chamber body.

The behavior of the mountain-shaped cold air flow is determined by the supply flow rate of the cool air and the exhaust air flow rate of the exhaust air, and is usually stable by selecting the latter slightly slightly larger than the former. Can be formed. Then, by performing temperature control to control the cooling power of the cooling device so that the temperature of the cool air supplied from the cool air port case becomes a predetermined target temperature, the cooling speed and the amount of cooling by the cool air can be freely adjusted. can do. In addition to this, the cooling rate and the cooling amount of the printed wiring board, which will be described later, can be adjusted by increasing or decreasing the absolute values of the flow rate and the flow rate of the cool air.

Therefore, when the surface to be soldered of the printed wiring board to which the molten solder is supplied is conveyed by the conveyor and passed through the position near the heat-recovery port of the heat-recovery port housing, a mountain-like cold air flow is generated. Rapidly cools the molten solder that flows in contact with the soldering surface and is supplied to the soldered part,
It becomes possible to rapidly solidify before solidification segregation or the like occurs. As a result, soldering with high mechanical connection strength can be performed.

In the process of cooling by the rapid cooling means, the air outside the chamber body is taken in and is blown and supplied to the printed wiring board as cold air having a low temperature by the cooling device.
At that time, the temperature rises by removing heat from the molten solder in the portion to be soldered. Then, the heated air is exhausted to the outside of the chamber to exhaust heat.

The cold air blown and supplied to the printed wiring board usually comes into contact with the molten solder at a temperature of 200 ° C. or higher and the temperature thereof rises, and therefore, is usually higher than the atmospheric temperature outside the chamber body. Therefore, the cooling efficiency of the cooling device can be enhanced by not returning the cooling device to the cooling device.
Further, the configuration of the present invention is extremely important because it is necessary to separately adjust the supply flow rate of the cool air and the discharge flow rate of the exhaust air to form a target mountain-like cool air flow.

(2) In the configuration of the soldering apparatus of the above (1), between the molten solder supply means and the heat-releasing port housing, facing the surface of the printed wiring board to be soldered. Thus, a heating means for keeping the printed wiring board warm is provided.

As a result, the temperature of the solder supplied to the portion to be soldered while the molten solder in the portion to be soldered of the printed wiring board supplied with the molten solder is conveyed to the heat-removing port housing decreases. Thus, the solder supplied to the portion to be soldered can be rapidly cooled and completely solidified by the heat removal port housing.

That is, there are cases where the means for supplying the molten solder to the printed wiring board and the means for rapidly cooling the printed wiring board cannot be arranged at a very short distance, the case where the conveying speed by the conveying means is slow, and the like. When the molten solder may be completely solidified before being supplied to the quenching means after the molten solder is supplied to the attachment part, the solidification of the molten solder is delayed by the heat retaining heating means, and the quenching means This allows rapid cooling at the heat removal port of the heat removal port housing to prevent solidification segregation and the like, thereby enabling soldering with high mechanical connection strength.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The soldering apparatus of the present invention can be implemented in the following embodiments.

(1) Configuration of Soldering Apparatus FIGS. 1A and 1B are views for explaining an embodiment of a soldering apparatus according to the present invention, wherein FIG. 1A is a side sectional view, and FIG.
It is the figure seen from the -I section. FIG. 2 is a view for explaining the configuration of a heat-removing port housing used in the soldering apparatus of the present invention, and is a view in which a part thereof is cut away and shown in a transparent manner.

In this embodiment, the lower surface in the drawing of the printed wiring board conveyed by the conveyor is the surface to be soldered, and the portion to be soldered exists on the surface side. Soldering is flow soldering.

That is, the conveyor 1 is provided at the entrance 1a.
The printed wiring board 6 is conveyed from the outlet 1b to the outlet 1b. The solder bath 5 for forming the preheating heater 2 and the jet wave 4 of the molten solder 3 is formed below the conveyer 1 along the conveying direction A. A quenching means 7 for quenching the soldered portion of the wiring board 6 is provided, and a tunnel-like chamber body 8 is provided along the transport conveyor 1 so as to cover them. The solder bath 5 for forming the jet wave 4 of the molten solder 3 is formed by immersing a skirt portion 9 provided at the opening of the chamber body 8 in the molten solder 3 so that the chamber wave of the jet wave 4 of the molten solder 3 is formed. 8 and sealing of the chamber body 8 is realized.

Then, the printed wiring board 6 and the molten solder 3
Above the position where the jet wave 4 contacts the solder bath 5
There of the chamber body 8 of the upper position is provided with N ₂ gas supply port 10, and consists of N ₂ gas cylinder and N ₂ gas generator (both not shown) to supply N ₂ gas into the chamber body . Although not shown, an oxygen concentration measuring device for measuring the oxygen concentration in the chamber body 8 is usually provided, and the N ₂ gas supply flow rate is adjusted so that the oxygen concentration becomes a predetermined value. Is being driven like so.

The suppression plate 1 provided in the chamber body 8
Reference numeral 1 denotes a member for forming a labyrinth flow path in the chamber body 8, whereby heat convection of the atmosphere in the chamber body 8 and take-out of the atmosphere in the chamber body 8 by the transfer conveyor 1 out of the chamber body 8. In addition, unnecessary flow of the atmosphere such as bringing in and flowing in the atmosphere outside the chamber body 8 is suppressed, and a stable inert gas atmosphere having a low oxygen concentration can be formed.

On the other hand, the molten solder 3 heated and melted by a heater (not shown) is accommodated in the solder bath 5.
The molten solder 3 is supplied to the outlet 14 of the nozzle body 13 by the pump 12 to form a jet wave 4, and the jet wave 4 is subjected to soldering of the printed wiring board 6 conveyed by the conveyor 1 in the direction of arrow A. The mounting surface 6a is brought into contact, and the molten solder 3 is supplied to the portion to be soldered to perform soldering. Of course, the heater power is controlled by a temperature adjusting means (not shown), and the temperature of the molten solder 3 is maintained at a target temperature.

Then, the printed wiring board 6 is
A quenching means 7 for rapidly cooling the soldered portion of the printed wiring board 6 is provided at a position immediately after being separated from the jet wave 4.

The quenching means 7 is roughly divided into a cold air supply means 15 for taking in the air outside the chamber body 8 for cooling and sending the air, and an air outside the chamber body 8 which is heated by cooling the printed wiring board 6 and whose temperature rises. The heat exhaust means 16 is configured to exhaust heat and exhaust heat to the outside, and a heat removal port housing 17 that forms a mountain-like cold air flow 30 that flows in a mountain shape and hardly leaks to the outside.

The cool air supply means 15 is composed of a fan 18 as a blow means and a chiller 19 as a cool means, and is configured so that the flow rate of the cooled cool air can be adjusted. In other words, although not shown, an inverter for adjusting the rotation speed of the fan 18 is provided, and the inverter adjusts the output frequency and output voltage to adjust the rotation speed of an induction motor (not shown) for driving the fan. is there.

Further, the chiller 19 is configured to be capable of feedback control of the degree of cooling, the cold air temperature signal S _t detected by the cold air temperature sensor 20 provided in the ablative heat port 17a of ablative thermal port housing 17 , And operates to maintain a predetermined temperature set in advance.

The exhaust heat means 16 is constituted by a fan 21 whose flow rate of exhaust air can be adjusted. Like the fan 18 of the cool air supply means 15, the rotational speed is adjusted by an inverter to adjust the flow rate of exhaust air, and the exhaust air is exhausted. This is a mechanism for discharging from the mouth 28.

On the other hand, the heat removal port housing 17 is connected to the cool air supply means 15 and the heat discharge means 16 and receives the supply of the cool air from the cool air supply means 15 as shown in FIG. The air outlet 22 includes a cool air outlet casing 22 that blows out from the air outlet 22 a and a heat exhaust outlet casing 23 connected to the heat exhausting means 16.
Then, the exhaust port 23a of the exhaust port 23 is
2 and surrounds the side circumference of the blowing port 22a to form the heat removal port 17a.
To form the heat-rejecting-port housing 17. The heat removal port housing 17 configured as described above is provided with the heat removal port 17a at a close position so as to face the surface 6a to be soldered of the printed wiring board 6 transported by the transport conveyor 1.

The cool air port housing 22 is provided with the cool air supply means 15.
Rectifier plate 2 that uniformly regulates the flow of cold air blown from
4 and, in particular, a flow straightening plate 25 in which a plurality of plate-like members for adjusting the flow direction are arranged in parallel. The cool air port case 22 is supported and fixed to the heat exhaust port case 23 by the support legs 32. Further, the cool air supply pipe 26 is a means for connecting the cool air supply means 15 and the cool air port housing 22 to
The heat discharge pipe 27 is a means for connecting the heat discharge port housing 23 and the heat discharge means 16.

The heat removal port 17a of the heat removal port housing 17 is configured so as to face the soldering surface 6a of the printed wiring board 6 in a very close manner.
It is preferable that the printed wiring board 6 is provided at a position within 5 seconds after the detachment from the molten solder 3 as much as possible. This is because the molten solder 3 supplied to the portion to be soldered of the printed wiring board can be cooled rapidly before the molten solder 3 is completely solidified within this time.

However, for example, in order to increase the contact time between the printed wiring board 6 and the jet wave 4 of the molten solder 3, it is necessary to reduce the conveying speed of the printed wiring board 6, If the printed wiring board 6 cannot be provided within 5 seconds after the printed wiring board 6 is separated from the molten solder 3 due to, for example, a case where the body 17 cannot be provided close to the jet wave 4 of the molten solder 3, A heating means for keeping the temperature of the solder of the soldered portion of the printed wiring board 6 between the jet wave 4 of the molten solder 3 formed in the solder bath 5 and the heat-rejecting port housing 17, that is, a heater for keeping the temperature. (Heating means for warming) 29 is provided.

As the heating means for keeping heat, a heating means mainly using a heat ray such as infrared rays, a hot air heating means for forming a high-temperature atmosphere by a heater, or a heating means using both of them are suitable. However, hot air must not be supplied at such a speed that the molten solder 3 supplied to the soldered portion is blown off or its fillet shape is deformed. That is, the electrical connection state and the mechanical connection state of the soldered portion are deteriorated by this, resulting in poor soldering.

The heater 29 shown in FIG.
A sheathed heater is arranged side by side in a box-shaped heater holder, and a stainless steel plate as an infrared reflecting plate is provided on the bottom surface of the holding frame. The heater 29 is disposed at a short distance (a distance of about 1 to 3 cm) facing the surface 6a to be soldered of the printed wiring board 6 conveyed by the conveyor 1.

Thus, infrared rays are radiated from the sheathed heater to the lower surface side of the printed wiring board 6, that is, to the surface 6 a to be soldered, and when the printed wiring board 6 is conveyed onto the heater 29, The wiring board 6 serves as a lid, so that a high-temperature atmosphere can be maintained between the wiring board 6 and the box-shaped heater holding frame, and the printed wiring board 6 and the soldered portion thereof can be well kept. By the way, at a distance of 3 cm or more, the outflow of the high-temperature atmosphere increases, and the heat retention power decreases extremely.

The temperature at which the printed wiring board 6 is maintained, that is, the temperature at which the molten solder 3 is supplied to the portion to be soldered, varies depending on the solder material used. In particular, when a lead-less solder contains bismuth, it is important from the viewpoint of preventing a lift-off phenomenon caused by the occurrence of solidification segregation.

As a result, the molten solder 3 supplied to the portion to be soldered of the printed wiring board 6 is kept warm, and is rapidly cooled and rapidly solidified by the heat removal port 17 a of the heat removal port housing 17 of the rapid cooling means 7. Will be able to do that.

In the present invention, the printed wiring board 6 is configured to be cooled by the cooled air without disturbing the atmosphere in the chamber body 8 holding the low-oxygen-concentration inert gas atmosphere. There are the most important features.

That is, as shown in FIG.
By forming the cooling air outlet 7, the cooled air outside the chamber body 8 blown out from the cold air outlet housing 22 immediately flows into the exhaust air outlet 23 a of the heat outlet housing 23, and the heat outlet of the heat outlet housing 17. At 17a, a mountain-like cold air flow 30 in a slightly raised state is formed. Therefore, the inert gas atmosphere with a low oxygen concentration held in the chamber body 8 is hardly subjected to disturbance such as supply of a large amount of air or unstable flow of the atmosphere.

The behavior of the mountain-like cold air flow 30 is determined by the supply flow rate of the cool air and the exhaust air flow rate of the exhaust air.
Usually, by selecting the latter slightly larger than the former, a stable mountain-like cold air flow 30 can be formed. That is, the mountain-like cold air flow 30 is formed by not circulating the cool air supply means 15 and the exhaust heat means 16 and independently adjusting the rotational speeds of the fans 18 and 21. Will be able to do it.

The cooling speed and the cooling amount of the molten solder 3 supplied to the portion to be soldered of the printed wiring board 6 are determined by the temperature of the mountain-like cold air flow 30 and its flow rate, and thus the flow rate. By using the chiller 19 provided with the chiller, the temperature of the cold air can be freely adjusted and set. The cooling speed and the cooling amount of the printed wiring board 6, which will be described later, can also be adjusted by increasing or decreasing the absolute values of the flow rate and the flow rate of the cool air.

Accordingly, the molten solder 3 is supplied to the portion to be soldered on the surface 6a to be soldered of the printed wiring board 6, and is conveyed and passed by the conveyer 1 at a position very close to the heat removal port 17a of the heat removal port housing 17. In this case, the mountain-shaped cold air flow 30 flows in contact with the surface 6a to be soldered, rapidly cools the molten solder 3 supplied to the soldered portion, and rapidly solidifies before solidification segregation or the like occurs. And soldering with high mechanical connection strength can be performed.

In the process of cooling the printed wiring board 6 by the rapid cooling means 7, the air outside the chamber body 8 is taken in, and cooled by the cooling means 19 to be blown and supplied to the printed wiring board 6 as cold air. In this process, the temperature is raised by removing heat from the molten solder 3 in the soldered portion, and the heated air (hot air) is exhausted to the outside of the chamber body 8 to perform heat exhaustion.

Here, the cold air blown and supplied to the printed wiring board 6 is usually in contact with the molten solder 3 at a temperature of 200 ° C. or higher, and the temperature is increased. Therefore, the temperature is usually higher than the atmospheric temperature outside the chamber body 8. Therefore, the cooling efficiency of the quenching means 7 can be greatly increased by not circulating and refluxing the cooling means 19.

Further, as described above, by providing the heater 29 for keeping the temperature between the jet wave 4 of the molten solder 3 and the heat sink housing 17, the printed wiring board 6 supplied with the molten solder 3 is provided. The temperature of the molten solder 3 in the portion to be soldered is prevented from lowering and completely solidifying while being conveyed to the heat-removing port housing 17, and the molten solder 3 supplied to the portion to be soldered is removed. The heat-recovery port housing 17 can be rapidly cooled and solidified at once.

That is, when the supplying means of the molten solder 3 to the printed wiring board 6 and the quenching means 7 of the printed wiring board 6 cannot be arranged at a close distance, or when the conveying speed by the conveying means is slow, the printing is performed. After the molten solder 3 is supplied to the portion to be soldered of the wiring board 6 and before the molten solder 3 is completely solidified before being conveyed to the quenching means 7, the heating means 29 for keeping heat is used. The solidification of the molten solder 3 is delayed, and rapid cooling is performed by the quenching means 7 at the heat-removing port 17 a of the heat-recovering port housing 17 to prevent solidification segregation and the like, and to perform soldering with high mechanical connection strength. Can be.

As described above, in the soldering apparatus of the present invention, the molten solder 3 supplied to the portion to be soldered of the printed wiring board 6 can be rapidly cooled before completely turning, and the machine can be cooled. The connection strength can be increased more than ever. Further, even when lead-free solder is used, occurrence of soldering failure such as a lift-off phenomenon can be prevented.

In the soldering apparatus illustrated in FIG.
The quenching means 7 for the printed wiring board 6 is
Although the example in which only the surface to be soldered 6a, that is, the surface on the lower side of the drawing is provided has been described, the rapid cooling means 7 having the same configuration is also provided on the upper side of the printed wiring board, and the printed wiring board 6 It is also possible to adopt a configuration in which rapid cooling is performed from both sides of the lower surface of the drawing, which is the surface 6a to be soldered, and the upper surface of the drawing.

In this case, not only the molten solder supplied to the soldered portion of the printed wiring board 6 but also the printed wiring board 6 itself can be rapidly cooled, so that the cooling speed of the molten solder 3 can be further increased. And the cooling amount can be further increased.

Further, as illustrated in FIG. 1A, the printed circuit board detection sensor 31 for detecting the entry of the printed circuit board 6 conveyed by the conveyer 1 is taken out of the heat port housing 17.
Provided in the upper, above the detection signal S _p reference to rotate the fan 21 for exhaust air fan 18 for cold air supply, a printed circuit board 6 as an object to be quenched workpiece deprive heat port housing 17 May be formed such that the mountain-like cold air flow 30 is formed only when is transported.

Alternatively, in a standby state in which the printed wiring board 6 does not enter, the rotational speeds of the cooling air supply fan 18 and the exhaust fan 21 are reduced, and the entering of the printed wiring board 6 is determined by the detection signal Sp. The rotation speed of both fans 18 and 21 may be increased to the normal rotation only when it is detected. Thereby, the power consumption of the chiller 19 for cooling the atmosphere can be further reduced, and the influence of the mountain-like cold air flow 30 on the atmosphere in the chamber body 8 can be further reduced. Become.

[0066] Such detection signal S _p rotation / stop control and rotational speed control of the fan by is possible by using a sequencer and a programmable controller or the like, examples of such control techniques are well known Therefore, the configuration is omitted and not shown.

[0067]

As described above, according to the soldering apparatus of the present invention, the molten solder supplied to the soldered portion of the printed wiring board, which is the work to be soldered, is rapidly cooled before being completely solidified. It becomes possible. In addition, the cooling temperature, cooling rate, and cooling amount can be freely adjusted.Moreover, the cooling state can be improved by the atmosphere while maintaining the flow state of the inert gas atmosphere with low oxygen concentration and the stable oxygen concentration. Cooling can be performed.

As a result, the soldering strength of the work to be soldered, that is, the mechanical connection strength can be greatly increased. Further, even when lead-free solder is used, a lift-off phenomenon does not occur, and a printed wiring board with high soldering reliability can be manufactured.

[Brief description of the drawings]

FIG. 1 is a view for explaining an embodiment of a soldering apparatus according to the present invention.

FIG. 2 is a view for explaining an example of the configuration of a heat removal port housing used in the soldering apparatus of the present invention.

[Explanation of symbols]

1 conveyor 2 preheating heater 3 molten solder 4 jets wave 5 solder bath 6 printed wiring board 6a to be soldered surface 7 quench means 8 chamber body 9 skirt 10 N ₂ gas supply port 11 inhibit plates 12 pump 13 nozzle body 14 Blow port 15 Cold air supply means 16 Heat removal means 17 Heat removal port housing 17a Heat removal port 18 Fan 19 Chiller (cooling means) 20 Cold air temperature sensor 21 Fan 22 Cold air port case 22a Air supply port 23 Heat exhaust port case 23a Air discharge port 24 Perforated rectifying plate 25 Rectifying plate 26 Cold air supply pipe 27 Exhaust heat pipe 28 Exhaust port 29 Heating heater 30 Mountain-like cold air flow 31 Printed wiring board detection sensor 32 Support leg

Continued on front page F-term (reference) 4E080 AA01 AB03 AB04 AB06 AB09 BA07 BA20 DA04 5E319 AC01 CC23 CC24 CC47 CC49 CD35

Claims (2)

[Claims] A conveying means for conveying a printed wiring board;
A tunnel-shaped chamber provided along the transfer means, an inert gas supply means for supplying an inert gas into the chamber, and a printed wiring board disposed in the chamber and transferred by the transfer means A molten solder supply means for supplying molten solder to a soldered portion on the side of the surface to be soldered, wherein the cooling means for taking in the atmosphere outside the chamber body and cooling to generate cool air; and the cooling. A cool air supply means comprising a blower means capable of adjusting a flow rate of the cool air cooled by the means, and blowing the cool air supplied from the cool air supply means from the blower port toward the printed wiring board to which the molten solder is supplied. A cold-air port case and a heat-discharge port case for collecting the hot air heated by cooling the printed wiring board and discharging the hot air from the exhaust port, A heat-dissipating port housing configured to form a heat-dissipating port by forming a discharge port of the heat-dissipating port box so as to surround a side periphery of a blow port of the cold-air port box; And a discharge means capable of adjusting a flow rate of the discharged air for discharging the discharged air to the printed wiring board. A soldering apparatus, wherein a heat removal port is provided facing the surface to be soldered of the printed wiring board. 2. A heating means for keeping the printed wiring board warm is provided between the molten solder supplying means and the heat-removing port housing and facing the surface to be soldered of the printed wiring board. The soldering apparatus according to claim 1, wherein: