JP2745723B2 - Soldering equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering apparatus used for flow soldering in a process of manufacturing a circuit board used for an electronic device or the like.

2. Description of the Related Art Generally, a surface mount circuit board is usually manufactured by the following steps.

(1) Printing of solder material (cream solder) on the board.

(2) Mounting components.

(3) Reflow soldering.

The conventional reflow soldering apparatus used in this step includes a tunnel-shaped furnace body 1, a conveyor 3 for conveying a circuit board 2 to be heated, a heater, and a cooling fan 5, as shown in FIG. Have. The circuit board 2 is placed on the conveyor 3 and transported in the furnace body 1 from the position A to the position A '. In the transfer process, the substrate 2 is heated by the width radiation heat from the heater 4 and the heat transfer of the air in the furnace 1 heated by the heater 4, and the cream solder printed on the substrate 2 is increased as the temperature of the circuit substrate 2 rises. After melting, air near room temperature is applied by the cooling fan 5 to be cooled, and the solder is solidified and the soldering is completed. In order for the solder to melt, it is necessary to heat the temperature at the peak point D in FIG. 9 to a temperature of about 200 ° C. The circuit board is usually covered with a material called a resist, but the resist is not applied to a portion of the circuit pattern that is connected to the lead of the component in order to maintain conduction between the component and the circuit pattern. For this reason, the surface of the circuit pattern formed on the substrate is oxidized during the heating process of the reflow, so that the soldering strength is weakened and the reliability is significantly reduced. On the other hand, conventionally, soldering is performed by purging the furnace with an inert gas such as nitrogen gas as a means to prevent oxidation, or by purging a reducing gas containing a small amount of hydrogen gas to reduce oxidation. The reliability of the strength was increased.

At this time, in order to prevent the outflow of the purge gas, the furnace body is designed to maintain high confidentiality, and various measures have been taken such as providing a shut-off mechanism such as a door 6 shown in FIG. . As shown in FIG. 11, the conventional shut-off mechanism usually includes a door body 7, an elastic body 8 for sealing provided at the tip of the door body 7, and an opening / closing mechanism 9 for the door body 7.

However, when the circuit board enters and exits, the door at the entrance must be opened and closed, and the purged gas flows into the furnace while the door is open. The amount of gas that flows out can reach several hundred slm, which greatly affects the operating cost of the soldering equipment, and also causes the gas supply facilities and systems to become larger and larger.

Therefore, an object of the present invention is to significantly reduce the amount of inert gas and reducing gas used in a soldering apparatus, reduce the operation cost of the apparatus, and simplify the facility of the apparatus.

Means for Solving the Problems According to a first invention for solving the above-mentioned problem, a vertically movable door-shaped outside air shutoff device provided near an entrance and exit of a furnace body is divided into upper and lower portions, and each door is opposed to each other. By providing two or more nozzles at the tip, at least one nozzle is an ejection nozzle for ejecting gas, and at least one other nozzle is an suction nozzle for sucking gas, thereby returning the suction gas to the ejection nozzle. It is characterized by having such a configuration.

Further, the second invention provides a honey chamber on the inlet side and the outlet side of the heating step, and a first vacuum pump for exhausting gas from the honey chamber to the outside of the furnace body for each honey chamber; A second vacuum pump for exhausting gas in the honey chamber to the heating step is provided.

According to a third aspect of the present invention, the outlet of the furnace body is sealed by a pair of substantially cylindrical rotating elastic bodies which are in contact with each other, and the circuit board is passed through a boundary between the rotating elastic bodies. I do.

Operation The operation according to the first invention will be described.

When the circuit board does not pass through the door-shaped outside air shut-off device (normal time), the door is in a closed state. This shuts off the outside air and the inert gas (or reducing gas) purged in the heating step, and prevents the purge gas from flowing out of the heating step. Immediately before the circuit board passes through the door, a door-shaped outside air shutoff device opens, and gas is ejected from an ejection nozzle provided at the tip of the door. The gas ejected from the ejection nozzle of one door is sucked and collected by the suction nozzle provided on the other door. When the circuit board passes between the doors (when the circuit board passes), the gas discharged from the ejection nozzle collides with the substrate surface, and is then sucked and collected by the suction nozzle provided on the same door.

As described above, since the ejection nozzle and the suction nozzle are combined according to the respective cases, the ejected gas can be reused without being discarded to the outside, and the effect of blocking the outside air is great.

Next, the operation of the second invention will be described. After the circuit board enters the honey chamber provided before the heating step, the outside air in the honey chamber is exhausted to the outside by the first vacuum pump. After the outside air in the honey chamber is sufficiently exhausted, the atmospheric gas in the heating process is introduced into the honey chamber by a pressure difference.
After the introduction of the atmospheric gas, the door to the heating step is opened from the honey chamber and the circuit board is carried into the heating step from the honey chamber. After the circuit board is carried in, the door of the honey chamber is closed and the atmosphere of the heating step of the honey chamber is returned to the heating step by the second vacuum pump. After the air is sufficiently exhausted, the door on the side opposite to the heating step, that is, on the circuit board carry-in side is opened, the honey chamber is filled with outside air, and then the board is carried in. Thereafter, the above-described operation is repeated. The same operation is performed in the honey chamber behind the heating step, so that it is possible to prevent the outside air from diffusing into the heating step and to suppress the outflow of the inert gas or the reducing gas used in the heating atmosphere.

Next, the operation of the third invention will be described. In general (when the substrate does not pass), the substantially cylindrical rotating bodies provided after the heating step are in elastic contact with each other, so that the atmospheric gas in the furnace body does not flow out of the contact portion. When the substrate passes, the substrate rotates from this elastic body while being in contact with the circuit board, and carries the substrate out of the heating process. The elastic body deforms according to the shape of the parts soldered to the circuit board due to its elasticity, so the gap created between the circuit elastic body and the circuit board and the components on the circuit board becomes extremely small, and flows out of the gap. Atmosphere gas in the heating step is very small.

Embodiment Hereinafter, a soldering apparatus according to an embodiment of the present invention will be described with reference to the drawings.

1 (a) to 1 (c), 2 and 3 show a first embodiment of the present invention, and FIG. 1 (a) is a perspective view of a state where a door of an outside air shutoff device is closed. FIG. 2B is a side view showing a state where the door is open, and FIG. 2C is a side view showing a state where the door is closed. 1 (a) to 1 (c), 11 is an upper door, 12 is a lower door, 13 is a gear mechanism for driving the upper door 11 up and down, and 14 is a gear mechanism for driving the lower door 12 up and down. Gear mechanism. Opposite distal ends of both doors 11, 12 are shaped to fit together in a closed state. FIG. 2 is a cross-sectional view of the door, 21 is a slit-shaped ejection nozzle provided at the tip of the upper door 11, 22 is a slit-shaped ejection nozzle provided at the tip of the lower door 12, and 23 is the upper side. A slit-shaped suction nozzle provided at the tip of the door 11, and a slit-shaped suction nozzle 24 provided at the tip of the lower door 12. 25 and 26 are circulation pumps of the upper door 11 and the lower door 12, 27 and 28 are deoxygenation filters for removing oxygen from the suction gas of the upper door 11 and the lower door 12,
Reference numerals 29 and 30 denote gas cylinders for supplying an inert gas or a reducing gas (hereinafter simply abbreviated as gas) to the suction gas of the upper door 11 and the lower door 12. 3 (a) and 3 (b) are diagrams showing gas flows.

The upper and lower doors 11 and 12 are opened and closed by respective gear mechanisms 13 and 14 as shown in FIGS. 1 (b) and 1 (c). The state shown in FIG. 3B is obtained immediately before the passage of the circuit board 31 until immediately after the passage, and the state shown in FIG.
State. Note that the alternate long and short dash lines in FIGS. 3B and 3C indicate positions where the substrate 31 passes.

The gas discharged from the ejection nozzle 21 is sucked by the suction nozzle 23 or 24. Similarly, the gas discharged from the ejection nozzle 22 is sucked by the suction nozzle 23 or 24. The sucked gas removes oxygen contained in the sucked air at the same time as the jet gas at the time of suction by the deoxygenating filters 27 and 28, and further adjusts the concentration by the gas supplied by the gas cylinders 29 and 30. It is discharged again from 21,22.

In addition, as shown in FIG. 1 (c), when the doors 11 and 12 are closed, that is, when the circuit board 31 does not pass, the pump
25 and 26 are stopped, and the supply of gas from the gas cylinders 29 and 30 is also stopped.

As shown in FIG. 3 (a), immediately before the circuit board 31 passes with the doors 11 and 12 opened, the gas discharged from the ejection nozzles 21 and 22 sucks the opposing doors as indicated by arrows. It is sucked from the nozzles 23 and 24. As shown in FIG.
When the circuit board 31 comes between the doors 11, 12, the ejection nozzle 21,
A part of the gas discharged from the nozzle 22 strikes the circuit board 31 and a part of the gas flows as shown by an arrow other than the suction nozzles 23 and 24, and the remaining gas is sucked and discharged by the suction nozzles 23 and 24 of the door on the discharged side. Collected.

In the case of this embodiment, when the doors 11 and 12 are closed, of course, the heating process and the gas outside the soldering apparatus are mixed,
In addition to preventing a large amount of gas from flowing out during the heating process of the soldering apparatus, even when the doors 11 and 12 are opened, the ejection nozzles 21 and 22 provided at the tips of the doors 11 and 12, and the suction nozzles 23 and The gas flowing between them serves as an air curtain, and the mixing of gas outside the heating process and the soldering apparatus and the outflow of gas during the heating process are reduced. Further, since the gas forming the air curtain is circulating, the gas consumption can be suppressed to a small amount.

 Next, a second embodiment of the present invention will be described.

FIG. 4 is a cross-sectional view of the holder of the present embodiment, wherein 41 is a circuit board, 42 is a conveyor 43 for transporting the circuit board 41, a nozzle for ejecting gas, 44 is a panel heater for radiating far infrared rays, 45, 46 is the inlet side of the heating step indicated by E
This is a honey chamber provided on the exit side. 47 is the honey chamber on the entrance side
A first vacuum pump for evacuating the gas in the chamber 45 to the outside of the soldering apparatus, and a second vacuum pump 48 for evacuating the gas in the honey chamber 45 to a heating step. Similarly, reference numerals 49 and 50 denote first and second vacuum pumps for exhausting the gas in the honey chamber 46 on the outlet side to the outside of the soldering apparatus and the heating step, respectively.

5 (a) to 5 (e) show pumps in the nectar chamber 45 on the inlet side.
FIG. 6 is a schematic diagram showing the relationship between the operations of 47 and 48 and the position of the circuit board 41.
2 is a door on the entrance side of the honey chamber, 63 is a door on the exit side of the honey chamber (entrance side to the heating process), 66 is a conveyor for transporting the circuit board 41,
67 is a chamber of the honey chamber 45.

In FIG. 9A, the door 62 on the entrance side is opened and the circuit board 41 is opened together with gas (air) outside the soldering apparatus.
It is carried into. When the circuit board 41 is completely in the chamber 67, the door 62 is closed, and the gas in the chamber 67 is exhausted by the first vacuum pump 47 (FIG. 2B). Chamber 67
The first vacuum pump 47 is stopped in a state where the gas is sufficiently exhausted (FIG. 10C), the door 63 on the outlet side is opened, and the circuit board 41 is opened.
Is carried out of the chamber 67 by the conveyor 66 during the heating process. (FIG. 2D). At this point, the gas in the heating process fills the chamber 67. After the circuit board 41 is carried out, the door 63 is closed again, and the gas in the chamber 67 is exhausted and returned to the heating step by the second vacuum pump 48 (FIG. 9E). When the next circuit board 41 arrives after the second vacuum pump 48 stops, the state returns to the state shown in FIG. 9A again, and a series of operations are repeated. The same operation is performed in the honey chamber 46 provided on the outlet side of the heating step.

In the present embodiment, the gas in the heating step and the air outside the soldering device are shut off by the double doors 62 and 63, and the gas is collected at the same time, so that the gas can be effectively used.

In the above embodiment, two vacuum pumps are used for one honey chamber. However, when gas is not collected, the second vacuum pump may not be used or the second vacuum pump may not be installed. Conceivable. Furthermore, the same function can be exhibited by switching the valve with one vacuum pump.

In the above embodiment, the gas outside the soldering apparatus and the gas in the heating step were introduced into the chamber by opening the door. However, when the door was difficult to open, a special valve and piping system was provided to provide the gas outside the soldering apparatus. It is also necessary to introduce the gas of the heating step into the chamber.

 Next, a third embodiment of the present invention will be described.

FIG. 6 is a sectional view of the soldering apparatus according to the present embodiment. In the figure, 71 is a circuit board, 72 is a conveyor for transport, 73 is a nozzle for ejecting gas, 74 is a panel heater that radiates far infrared rays, and 75 is a loading side (entrance side) of the circuit board 71.
The outside air shut-off device 76 is a pair of mutually contacting cylindrical elastic rotary members provided as an air shut-off device on the carry-out side (exit side) of the circuit board 71. 7 (a) to 7 (c) are enlarged views of the rotary elastic body 76. In FIG. 7 (a), 81 is an upper rotary elastic body, and 82 is a lower rotary elastic body. The rotating elastic bodies 81 and 82 rotate while being in contact with each other in the direction of the arrow by a drive mechanism not shown in the drawing. When the circuit board 71 does not pass through, the rotating elastic bodies 81 and 82 are in contact with each other, so that the gas on the IN side and the air on the OUT side near the plane where the circuit board 71 passes are cut off, and・ Inflow of air is also prevented. On the side of the rotating elastic bodies 81 and 82 that do not contact each other, a different type of gas inside and outside the soldering device is provided by providing a blade-shaped mechanism 84 that contacts the rotating elastic bodies 81 and 82 as shown in FIG. Mixing is prevented, and at the same time, outflow of gas and inflow of air can be suppressed.
When the circuit board 71 passes between the rotating elastic bodies 81 and 82 and is carried out of the soldering device as shown in FIG. It is elastically deformed according to the component height.

As described above, since the rotating elastic bodies 81 and 82 are almost in close contact with the circuit board 71 and the components, it is possible to prevent mixing of different types of gas inside and outside of the soldering apparatus, outflow of gas, and inflow of air. In addition, since the rotating elastic bodies 81 and 82 are rotating, they also have a function of carrying out the circuit board 71, and at the same time, apply an elastic force perpendicular to the transfer surface with respect to changes in the thickness of the circuit board 71 and height of parts. The force which takes the form and removes the component from the substrate 71 is hardly applied.

Effects of the Invention As described above, according to the first aspect of the present invention, a soldering device is provided by a gas ejected from a nozzle provided at a tip of the door in a state where the door is opened and collected and circulated, together with a blocking effect of the door itself. The gas inside is shut off from the air outside the device, and the device can be operated at low cost.

According to the second invention, the gas and the air are shut off by the double door, and at the same time, the mixing of the air and the gas is prevented by the exhaust of the pump, and the gas is recovered. Available.

According to the third aspect, when the circuit board is carried out,
Since the rotating elastic body is in close contact with the circuit board, outflow and mixing of gas can be avoided, and the apparatus can be operated at low cost.

[Brief description of the drawings]

1 (a) to 1 (c) are configuration diagrams showing a soldering apparatus according to a first embodiment of the present invention, and FIG. 2 is a block diagram of a door which is a shut-off mechanism including a piping system of the embodiment. 3 (a) and 3 (b) are side views showing gas flows in the embodiment, FIG. 4 is a cross-sectional view of a soldering apparatus in a second embodiment of the present invention, and FIG. 6 (a) to 6 (e) are configuration diagrams showing the operation of the embodiment, FIG. 6 is a sectional view of a soldering apparatus in a third embodiment of the present invention, and FIGS. 7 (a) to 7 (c) are FIG. 8 is a cross-sectional view of a conventional soldering apparatus, FIG. 9 is a temperature-time change characteristic diagram during soldering, FIG. 10 is a cross-sectional view of a conventional gas purge type soldering apparatus, FIGS. 11 (a) and 11 (b) are enlarged views of the shut-off mechanism of the device. 11,12 …… Door-shaped shut-off mechanism, 21,22 …… Squirting nozzle, 23,24
…… Suction nozzle, 25,26 …… Pump, 45,46 …… Honey chamber,
47, 49: First vacuum pump, 48, 50: Second vacuum pump, 81, 82: Substantially cylindrical rotary elastic body.

Claims (3)

(57) [Claims] 1. A heating device for heating an object to be heated, such as a circuit board on which electronic components are mounted, has a conveying means for conveying the object to be heated, and a gas sending means for sending an inert gas or a reducing gas. In a soldering apparatus, two or more nozzles are provided at opposing ends of a door-shaped outside air shutoff device that is provided near an entrance and exit of a furnace body and is vertically divided and performs opening and closing operations, and at least one nozzle is provided. A soldering apparatus characterized in that the nozzle is an ejection nozzle for ejecting gas, and at least another nozzle is a suction nozzle for sucking gas, so that the suction gas is returned to the ejection nozzle. 2. A heating apparatus for heating an object to be heated, such as a circuit board on which electronic components are mounted, has a conveying means for conveying the object to be heated, and a gas sending means for sending an inert gas or a reducing gas. In the soldering equipment, as a mechanism to shut off the atmosphere of the heating process from the outside atmosphere,
A first vacuum pump for providing each honey chamber on the outlet side and exhausting the gas in the honey chamber to the outside of the furnace body for each honey chamber, and a second vacuum pump for exhausting the gas in the honey chamber to the heating step. 2. A soldering apparatus comprising: a vacuum pump; 3. A furnace for heating an object to be heated such as a circuit board on which an electronic component is mounted, a conveying means for conveying the object to be heated, and a gas sending means for sending an inert gas or a reducing gas. In the soldering equipment, the outlet of the furnace
A soldering apparatus comprising a pair of substantially cylindrical rotating elastic bodies which are in contact with each other and hermetically sealed so that the substrate passes through a boundary between the rotating elastic bodies.