JPH0685450A - Automatic soldering device - Google Patents

Abstract

PURPOSE:To sustain the high airtightness on a junction surface by a method wherein a case body is halved and then hollow elastic member sealed with a gas are arranged on the junction parts to sustain the airtightness within the automatic soldering device wherein a substrate with electronic parts is heated while being carried to be soldered in a heating chamber filled up with an inert gas. CONSTITUTION:Multiple case bodies 11 vertically halved is to be a box body wherein heating chamber 15 to be an inert gas chamber filled up with nitrogen gas for soldering step is held by hollow members 14 in the same shape as that of the junction part between the junction parts 11a and 11b so as to sustain the airtightness. At this time, the nitrogen gas at the pressure of 0.2-1kg/cm<2> is sealed in this case body. When a substrate 19 and electronic part 30 are preliminarily heated, carried to a reflow soldering chamber to be brought into contact with the nitrogen gas heated at about 250 deg.C, a creamy solder is fused to solder the electronic parts 30 onto the substrate 19. At this time, within the heating chamber 15 filled up with the nitrogen gas in low oxygen concentration, the fused solder and lead wire of the electronic parts 30 are not to be oxidized at all.

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 in particular, a plurality of housings are provided by arranging a hollow elastic member in which a gas such as an inert gas is sealed in a joint portion of divided housings. By forming an inert gas chamber by joining, it is possible to maintain high airtightness at the joint even if the processing accuracy of the joint surface is not very good, and the inert gas chamber can be easily disassembled for maintainability. The present invention relates to an automatic soldering device having a significantly improved temperature.

[0002]

2. Description of the Related Art Conventionally, in an automatic soldering apparatus, an electronic component is soldered to a substrate by melting the solder by raising the temperature of the substrate and the solder to a high temperature in an atmosphere containing a large amount of oxygen. According to the automatic soldering device, the soldering part and the molten solder are oxidized when the solder and electronic parts are exposed to oxygen at high temperature, and it is not possible to secure sufficient soldering performance, It had the disadvantage of having to do some work.

In particular, as electronic components have become smaller in recent years and the lead wires have become thinner accordingly, even a slight defect such as oxidation of a soldered portion has serious consequences such as deterioration of reliability of electronic products. It was the cause.

In order to solve such a drawback, the automatic soldering apparatus is filled with an inert gas such as nitrogen gas to perform soldering in a state where oxygen is blocked, and the electronic parts, the substrate and the solder are heated to a high temperature. In addition, an automatic soldering device has been proposed in which soldering is performed so that a soldering portion and molten solder are not oxidized.

Since the inert gas such as nitrogen gas used in this type of automatic soldering device is expensive, it is necessary to minimize the leakage of the inert gas from the automatic soldering device. Various measures have been taken to increase the tightness of the device.

In order to improve the airtightness of the automatic soldering device, it is conceivable that the housing containing the soldering device is integrally manufactured by welding or the like to form a completely hermetically sealed structure. Maintenance or repair of the built-in soldering device was very difficult at the time of inspection or failure, which was not practical.

For this reason, a housing is usually divided into upper and lower parts, and an elastic member is sandwiched between the two housings to join them.
An apparatus has been put into practical use, which seals the joint and maintains the airtightness of the automatic soldering apparatus.

In such a conventional example, in FIG. 5, one housing 1 in which a joint surface 1a is formed in a planar shape and a joint surface 2 are formed.
A solid elastic member 3 having a rectangular cross section is mounted between the housing 2 and the other housing 2 in which an elastic member storage chamber having a rectangular cross section is formed in a.
The housings 1 and 2 are tightened with bolts 4 and nuts 5 to maintain the airtightness of the joint portion 6.

As another conventional example, in FIGS. 6 and 7, one housing 1 in which the joint surface 1a is formed in a wedge shape and the other in which the elastic member storage chamber having a rectangular cross section is formed in the joint surface 2a A solid elastic member 8 having a round cross-section is mounted between the housing 2 and the housing 2, and the housings 1 and 2 are tightened with bolts 4 and nuts 5 so that the wedge-shaped joint surface 1a is cut into the elastic member 8. (See FIG. 7) The airtightness of the joint 6 is maintained.

On the other hand, since the automatic soldering device is constructed so as to solder the substrate while continuously transferring it,
Some of them have a large length, and some have a length of 10 m or more. Therefore, it is difficult to manufacture the bonding surfaces 1a and 2a of such large housings 1 with very high surface accuracy, and unevenness is inevitable. I will end up.

In FIG. 8, if the joint surfaces 1a and 2a have irregularities, even if the casings 1 and 2 are firmly tightened with the bolts 4 and the nuts 5, only the elastic members 3 and 8 seal the joint portion 6 over the entire length. It is difficult to stop and maintain the airtightness, and there is a drawback that the clearance 9 is generated and expensive inert gas flows out from the clearance 9 and is consumed.

In addition, the joint surface 1a,
It is technically possible to machine the surface precision of 2a well, but since the device is large, it requires a large amount of cost and is practically impossible.

In addition, with the outflow of the inert gas from the gap 9, air flows into the automatic soldering apparatus from the carry-in port of the substrate to reduce the density of the inert gas in the preheating chamber, thereby preventing oxidation. Will be reduced.

As a device for preventing the inflow of air from the carry-in port, there has been proposed a device for supplying more inert gas than that flowing out from the carry-out port to increase the internal pressure in the automatic soldering device. However, this device has a drawback that it requires an extremely large amount of inert gas and is not economical.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art. The object of the present invention is to provide a housing which constitutes an inert gas chamber.
The hollow elastic member is divided into parts, and a hollow elastic member in which a gas is filled is disposed in the joint portion of the housing so as to maintain airtightness, so that the hollow elastic member is closely adhered along the joint surface of the housing. That is, even if the surface accuracy of the joint surface is not so good, extremely high airtightness can be maintained.

Another object is to divide the casing constituting the inert gas chamber into two parts, and to arrange a hollow elastic member in which an inert gas is sealed in the joint part of the casing to maintain airtightness. By configuring so that the hollow elastic member is closely adhered following the joint surface of the housing so that extremely high airtightness can be maintained even if the surface accuracy of the joint surface is not very good. Even if the inert gas leaks from the inside of the elastic member into the automatic soldering device, the stable soldering performance can always be ensured without affecting the inert gas concentration in the device.

Still another object of the present invention is to make it possible to maintain a high airtightness of the joint by simply joining the two divided casings with an appropriate tightening force.

Still another object is to dispose the locking piece and the engaging member in the housing, and to engage the engaging member with the locking piece with the hollow elastic member mounted between the housings so as to secure the hollow elastic member. By pressing and assembling the inert gas chamber, the automatic soldering apparatus can be easily disassembled and assembled to improve the maintainability.

[0019]

SUMMARY OF THE INVENTION In summary, the present invention (Claim 1) relates to an automatic soldering device for heating and soldering a substrate on which electronic components are mounted while being transported in a heating chamber filled with an inert gas, A plurality of casings that form an inert gas chamber by joining them, and a hollow elastic member that is disposed in a joint portion of the casings and in which gas is enclosed are provided, and the hollow elastic members are sandwiched by the casings. It is characterized by being configured in.

Further, the present invention (claim 2) is an automatic soldering device for heating and soldering a substrate on which electronic components are mounted while being transported in a heating chamber filled with an inert gas,
A plurality of casings that form an inert gas chamber by joining them, and a hollow elastic member that is disposed in the joint portion of the casings and in which an inert gas is sealed are sandwiched between the casings. It is characterized in that it is configured to.

The present invention (claim 3) is an automatic soldering apparatus for heating and soldering a substrate on which electronic components are mounted while being transported in a heating chamber filled with an inert gas,
A plurality of housings that form an inert gas chamber by joining, a locking piece formed on one of the plurality of housings, and the other housing corresponding to the locking piece. The engaging member and a hollow elastic member which is disposed in the joint portion of the housing and in which an inert gas is sealed, and the locking piece is attached to the locking piece with the hollow elastic member mounted between the housings. It is characterized in that the engaging member is engaged and the hollow elastic member is pressed.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. 1 and 2, an automatic soldering device 10 according to the present invention includes a plurality of vertically divided housings 11, a locking piece 12, an engaging member 13, and a hollow elastic member 14. .

An embodiment in which the present invention is used in a reflow type automatic soldering apparatus 10 as an example of an automatic soldering apparatus will be described below with reference to FIG.

First, the basic structure of the reflow-type automatic soldering device 10 will be described. The housing 11 of the reflow-type automatic soldering device 10 includes an upper frame 11A and a lower frame 11.
It is divided into B and manufactured.

The inside of the housing 11 is an inert gas chamber divided by a partition wall (not shown) into two preheating chambers, a reflow soldering chamber and a slow cooling chamber (each not shown separately). The heating chamber 15 is formed, and the structure of each chamber is
The structure is almost the same except that the internal temperature is different.

A well-known endless chain conveyor 16 which is an example of a conveying device is provided so as to penetrate through the preheating chamber, the reflow soldering chamber and the slow cooling chamber, and the substrate carried in at the carry-in station 18 is provided. It is configured such that 19 is sequentially conveyed to the preheating chamber, the reflow soldering chamber, and the slow cooling chamber to be soldered, and is carried out to the carry-out station 20.

A casing 21 is provided in a preheating chamber, a reflow soldering chamber, and a slow cooling chamber which are independently filled with an inert gas such as nitrogen gas, and a casing 21 is disposed in the lower frame of the heating chamber 15. Ascending circulation passage 15U between body 11B
However, a descending circulation passage 15D is formed in the casing 21.

Chain conveyor 16 in casing 21
A heating device 24 having a sandwich structure in which the electric heater 22 is sandwiched by the metal plates 23 having a large number of holes 23a is disposed above the above, and the two preheating chambers each have a temperature of about 190 ° C. The reflow soldering chamber is heated to about 250 ° C., and the slow cooling chamber is heated to about 130 ° C.

Substrate 1 mounted on the chain conveyor 16
9 is preheated in the preheating chamber while being transported,
The reflow soldering chamber is rapidly heated to the soldering temperature for soldering, and is gradually cooled in the slow cooling chamber to be carried out from the carry-out station 20.

The blower 25 is for forcedly circulating the heated inert gas such as nitrogen gas filled in the heating chamber 15, and is provided below the preheating chamber, the reflow soldering chamber and the slow cooling chamber. A belt (not shown) is wound between a pulley 29 fixed to a shaft 28 supported by a bearing 26 such as a ball bearing in a centrifugal blower such as a sirocco fan and a pulley of a motor (not shown). And is driven by the motor.

Then, after the nitrogen gas filling the heating chamber 15 is sucked and heated by the heating device 24, the descending circulation passage 15
After lowering the inside of D in the direction of arrow A to heat the substrate 19 conveyed by the chain conveyor 16, the blower 25 pressure-feeds it in the direction of arrow B to raise it again in the direction of arrow C through the ascending circulation passage 15U to circulate it. Is configured.

The substrate 1 is heated by the heated nitrogen gas.
9 is gradually heated to the soldering temperature to solder the electronic component 30 to the substrate 19.

The plurality of housings 11 divided into upper and lower parts are boxes for filling the heating chamber 15 serving as an inert gas chamber with nitrogen gas for soldering, and have an upper part manufactured in a hermetically sealed structure. The heating chamber 1 is composed of a housing 11A and a lower housing 11B, and the upper housing 11A and the lower housing 11B are joined together by making their open end sides face each other so as to be joined to each other, thereby forming an inert gas chamber.
5 is formed.

The edges of the upper casing 11A and the lower casing 11B on the open end side are joined portions 11a and 11 having an L-shaped cross section, respectively.
b is welded over the entire circumference, and the hollow elastic member 14
Is sandwiched between the two joint portions 11a and 11b.

Mainly referring to FIG. 3, the locking piece 12 is for joining the upper casing 11A to the lower casing 11B, and has a plurality of protrusions 11c at the joining portion 11a of the upper casing 11A. It is formed continuously.

The engaging members 13 are for joining the upper housing 11A and the lower housing 11B in cooperation with the locking pieces 12, and are arranged at positions corresponding to the locking pieces 12, respectively. The support base 31 is fixed to the joint portion 11b of the lower housing 11B by bolts 32 and nuts 33.

A connecting link 35 is rotatably connected between the supporting base 31 and the hook-shaped engaging arm 34 by shafts 36 and 38, and the hook portion 34a of the engaging arm 34 is connected. The upper housing 11A and the lower frame 11B are joined by engaging with the locking piece 12 and rotating in the direction of arrow D.

The hollow elastic member 14 includes the joint portions 11a and 11a.
It is a hollow silicon rubber tube having a high airtightness, which is disposed between b and maintains the airtightness of the joint, and is formed in the same shape as the joint 11a. A nitrogen gas having a pressure of 0.2 to 1 kg / cm ² is supplied from the nitrogen gas supply device 39 in the direction of arrow F to be sealed.

A pressure gauge 41 is attached to the pipe 40 to measure the pressure of the nitrogen gas sealed in the hollow elastic member 14.

The present invention is configured as described above,
The operation will be described below. In FIG. 1 and FIG. 2, first, in the carry-in station 18, the substrate 19 is mounted on the chain conveyor 16, and the substrate 19 is conveyed by the chain conveyor 16 and the nitrogen gas is converted to about 190
A relatively small electronic component with a small heat capacity, which is rapidly heated in a preheating chamber heated to ℃, is immediately heated to about 190 ° C, which is the same as the temperature of nitrogen gas, but a relatively large heat capacity. The electronic parts have a surface area of about 190
While it is heated up to ℃, the inside is not sufficiently heated and the temperature is lower than this.

Next, it is transferred to the next preheating chamber heated to about 150 ° C., the temperature of the electronic parts having a small heat capacity is lowered, and the electronic parts having a large heat capacity is gradually heated to adjust the whole temperature. Then, all the components of the substrate 19 and the electronic component 30 reach a uniform temperature of about 150 ° C., and the preheating is completed.

The nitrogen gas contacting the substrate 19 from above is
The flow branches in the left-right direction and the direction of the flow is the substrate 19
Since the position of the substrate 19 being conveyed is determined by the positional relationship between the air blower 25 and the blower 25, the flow direction also changes from right to left and from left to right. In the pre-heating chamber, the nitrogen gas flows in the direction of flowing out to the carry-in station 18 or in the direction of the next pre-heating chamber opposite to the carry-in station 18.

The nitrogen gas that has passed through the chain conveyor 16 and further descended in the direction of arrow A is sucked by the blower 25, flows leftward and rightward in the direction of arrow B, and rises in the circulation passage 15
It goes up in U and returns above the heating device 24.

At this time, the temperature of the nitrogen gas is detected by a temperature sensor (not shown) and transmitted to a control device (not shown), and the electric power supplied to the heating device 24 is adjusted by the command of the control device to heat the heating device 24. The nitrogen gas in the chamber 15 is controlled to have a predetermined temperature.

Next, the substrate 19 is conveyed to the reflow soldering chamber, where it is heated in contact with the nitrogen gas heated to about 250 ° C. in the same manner as the preheating chamber. The component 30 is soldered to a predetermined portion of the board 19.

In the preheating chamber and the reflow soldering chamber,
Since it is filled with nitrogen gas whose oxygen concentration is kept extremely low at about 500 ppm, the molten solder and electronic parts 3
The 0 lead wire and the like are not oxidized, and ideal soldering is performed.

The substrate 19 which has been soldered in the reflow soldering chamber and is still in a high temperature state is further conveyed to the slow cooling chamber at a temperature of about 130 ° C., slowly cooled, and then conveyed to the carry-out station 20. Be shipped.

The electronic component 30 is soldered to the substrate 19 as described above. The soldering performance is greatly affected by the oxygen concentration in the heating chamber 15, and how the inertness of the heating chamber 15 is maintained. Is important.

Referring also to FIG. 4, the hollow elastic member (for example, a silicone rubber tube) 14 has joint portions 11a and 11b.
The hollow elastic member 14 is provided in the space and is filled with nitrogen gas having a pressure of 0.2 to 1 kg / cm ^{2 in} the direction of arrow F, so that the hollow elastic member 14 has the shape of the joints 11a and 11b. It deforms along the line and completely seals the gap between the upper housing 11A and the lower housing 11B to maintain the airtightness of the housing 11.

The enclosed nitrogen gas leaks from the inside of the hollow elastic member 14 little by little in the direction of arrow E through the hollow elastic member 14, but the nitrogen gas is the same as the gas filled in the heating chamber 15. Since it is an inert gas, it does not affect the soldering performance.

The gas sealed in the hollow elastic member 14 is
Although it has been described as an inert gas such as nitrogen gas, it is also conceivable that a certain amount of external air is intentionally supplied into the heating chamber 15 to control the inert gas concentration in the heating chamber to a desired value. In such a case, the hollow elastic member 14
The gas to be sealed in may be air.

In the above embodiments, the present invention is described as being applied to a reflow type automatic soldering device, but the application of the present invention is not limited to the reflow type automatic soldering device, and a jet type Of course, it can also be applied to a dip type automatic soldering device.

[0053]

As described above, according to the present invention, the casing forming the inert gas chamber is divided into two parts, and a hollow elastic member in which a gas is filled is arranged at the joint part of the casing to provide airtightness. Since the hollow elastic member is closely adhered along the joint surface of the housing, the airtightness can be kept extremely high even if the surface accuracy of the joint surface is not so good.

Further, the casing constituting the inert gas chamber is divided into two, and a hollow elastic member filled with an inert gas is arranged at the joint portion of the casing so as to maintain airtightness. Therefore, there is an effect that the hollow elastic member can be closely adhered following the joint surface of the housing to maintain extremely high airtightness even if the surface accuracy of the joint surface is not so good, and an inert gas is generated from the inside of the hollow elastic member. Even if it leaks into the automatic soldering device, it does not affect the inert gas concentration in the device and can always ensure stable soldering performance.

Further, with the above structure, there is an effect that the high airtightness of the joint can be maintained only by joining the two divided casings with an appropriate tightening force.

Further, a locking piece and an engaging member are arranged on the housing,
With the hollow elastic member mounted between the housings, the engaging member is engaged with the locking piece to press the hollow elastic member to assemble the inert gas chamber, so that the automatic soldering device can be disassembled and assembled. There is an effect that it becomes easy and the maintainability can be improved.

[Brief description of drawings]

1 to 4 relate to an embodiment of the present invention, and FIG. 1 is an exploded perspective view of a housing and a hollow elastic member of an automatic soldering device.

FIG. 2 is a vertical sectional view of a heating chamber of the automatic soldering device.

FIG. 3 is an enlarged vertical sectional view of an essential part showing the action of a hollow elastic member mounted between the housings.

FIG. 4 is a vertical sectional view taken along the line IV-IV of FIG.

FIG. 5 to FIG. 8 relate to a conventional example, and FIG. 5 is an enlarged vertical cross-sectional view of a solid elastic member mounted between housings.

FIG. 6 is an enlarged vertical cross-sectional view of a solid round elastic member mounted between the housings.

FIG. 7 is an enlarged vertical cross-sectional view showing a state where one of the casings bites into and is joined to the solid instep round elastic member.

FIG. 8 is a vertical cross-sectional view taken along the line VIII-VIII of FIGS. 5 to 7.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Automatic soldering apparatus 11 Multiple housings 11A Upper housing which is an example of one housing 11B Lower housing which is an example of the other housing 11a Joint part 11b Joint part 12 Engaging member 13 Engaging member 14 Hollow elastic member 15 Heating chamber 19 Substrate 30 Electronic component

Claims (3)

[Claims] 1. An automatic soldering device that heats and solders a substrate on which electronic components are mounted while being transported in a heating chamber filled with an inert gas, and a plurality of housings that form an inert gas chamber by joining them together. An automatic soldering device, comprising: a hollow elastic member, which is disposed at a joint portion of the housing and in which gas is enclosed, and the hollow elastic member is sandwiched by the housing. 2. An automatic soldering device that heats and solders a substrate on which electronic components are mounted while being conveyed in a heating chamber filled with an inert gas, and a plurality of housings that form an inert gas chamber by joining them together. And a hollow elastic member which is disposed in a joint portion of the housing and in which an inert gas is sealed, and the hollow elastic member is sandwiched between the housings. . 3. An automatic soldering device that heats and solders a substrate on which electronic components are mounted while being transported in a heating chamber filled with an inert gas, and a plurality of housings that form an inert gas chamber by joining them together. A locking piece formed on one of the plurality of housings, an engagement member arranged on the other housing corresponding to the locking piece, and a locking piece disposed at a joint portion of the housings. A hollow elastic member in which an inert gas is filled, and the hollow elastic member is fitted between the housings to engage the engaging member with the engaging member to press the hollow elastic member. An automatic soldering device characterized in that