JP3442096B2 - Reflow equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to soldering by causing a hot air flow to flow toward a circuit board while preliminarily supplying a cream solder to a plurality of zones in a reflow furnace along a transfer path. The present invention relates to a reflow device that

[0002]

2. Description of the Related Art A conventional reflow apparatus that heats and solders a circuit board preliminarily supplied with cream solder in a plurality of zones in a reflow furnace along a transfer path while heating the circuit board in the atmosphere is known. It is described in Kaihei No. 2-137691.

In this type of reflow device, as shown in FIG. 12, a circuit board 61 to which cream solder has been previously supplied is
After being charged into the reflow furnace 63 from the inlet of the transfer path 62, it is moved along the transfer path 62 over each zone of the first preheating section 64, the second preheating section 65, the reflow section 66, and the cooling section 69. Then, the circuit board 61 includes the first preheating unit 6
4. After being gradually heated by the second preheating unit 65, the reflow unit 66 further heats and solders. In addition, 67 is a heater, and in the 1st preheating part 64, the 2nd preheating part 65, and the reflow part 66, the conveyance path 6 is each.
It is arranged at a position just above 2 at a predetermined interval.

[0004]

However, in the reflow apparatus having the above-mentioned conventional structure, the heater 67 is provided in the conveying path 6.
2, the airflow 70 heated near the heater 67 and the airflow 71 passing through the center between the heaters 67 and not heated so much are not circulated and mixed. There is a problem in that the circuit board 61 on the transfer path 62 is caught in a state where the temperature and the wind speed of the airflows 70 and 71 vary, and a good reflow condition cannot be obtained.

The present invention solves the above problems, and an object of the present invention is to provide a reflow apparatus capable of sending an air stream having a uniform temperature and a uniform wind speed toward a circuit board on a transfer path. .

[0006]

In order to solve the above problems, the first means of the present invention is a reflow apparatus having a conveying path extending over a plurality of zones, and means for heating an air flow and this heated means. A passage for guiding the heat flow in a lateral direction above the transfer path in a direction orthogonal to the substrate transfer direction, and a straightening plate for guiding the heat flow passing through the path downward toward the substrate in the substrate transfer direction. A plurality of them are provided in the transverse direction orthogonal to each other, and the current plate is slidable in the transverse direction orthogonal to the substrate transport direction. A second means of the present invention is a reflow device having a transfer path extending over a plurality of zones, the means for heating an air flow, and the heated hot air flow being orthogonal to the substrate transfer direction above the transfer path. A plurality of straightening vanes for guiding the hot air flow that has passed through this passage downward toward the substrate are provided in a lateral direction orthogonal to the substrate transport direction, and It is characterized in that the straightening vanes are arranged such that the distance and the distance between the straightening vanes and the wall surface of the hot air flow descending guide become smaller toward the downstream side in the lateral flow direction of the hot draft. A third means of the present invention is a reflow device having a transfer path extending over a plurality of zones, wherein the means for heating the air flow and the heated hot air flow are orthogonal to the substrate transfer direction above the transfer path. And a plurality of straightening vanes for guiding the hot air flow passing through the passages downward toward the substrate are provided in a lateral direction orthogonal to the substrate transport direction. It is characterized in that it is arranged on the downstream side in the lateral flow direction of the flow. A fourth means of the present invention is a reflow device having a transfer path extending over a plurality of zones, wherein the means for heating the air flow and the heated hot air flow are orthogonal to the substrate transfer direction above the transfer path. A plurality of straightening vanes are provided in the lateral direction orthogonal to the substrate transport direction, and both edges are bent downward. Bending nozzles having a slit-shaped opening formed by arranging a plurality of bent plate materials having a cross-sectional shape in the substrate transport direction at regular intervals are provided below the flow straightening plate, and are blown to the end portion of the blowing nozzle. also the in which you characterized in that a notch to flow out the airflow that has flowed to the back side of the nozzle to the outside.

[0007]

[0008]

[0009]

[0010]

[0011]

[0012]

[Action] More said first hand stage, since the hot air stream flowing in the lateral direction perpendicular to the substrate conveying direction Charles Shirubebi downward toward the circuit board of the conveying path by the rectifying plate, the flow direction and velocity of the inner air flow In particular, it is possible to make the flow direction and the wind speed of the internal airflow near the transport path constant. Further, by sliding the straightening plate in the lateral direction orthogonal to the substrate transport direction, it is possible to easily adjust the air volume of the hot air flow in the lateral direction orthogonal to the substrate transport direction. By the second hand was Dhamma <br/> third means, for hot air flowing in the lateral direction perpendicular to the substrate conveying direction Charles Shirubebi downward toward the circuit board of the conveying path by the rectifying plate, The flow direction and the wind speed of the internal air flow, especially the flow direction and the wind speed of the internal air flow in the vicinity of the transport path can be made constant. Further, the wind velocity of the hot air flow can be made uniform in the lateral direction orthogonal to the substrate transport direction. By the fourth means, the flow of heat flowing in the lateral direction orthogonal to the substrate transfer direction is guided downward by the straightening plate toward the circuit board in the transfer path, so that the flow direction and wind speed of the internal air flow, especially near the transfer path. The flow direction and wind speed of the internal air flow can be made constant. Further, the blowing nozzle can jet the hot air flow toward the circuit board while satisfactorily dispersing the hot air flow also in the board transport direction. Further, the cutout portion can prevent the hot air flow from staying behind the blowing nozzle.

[0013]

[0014]

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 2, in the reflow furnace 1, the inlet resistance units 3, 3 are arranged in order from the upstream side along the transfer path of the circuit board 2 (see FIG. 1) (path between the board transfer directions A).
Preheating first zone section 4, preheating second zone section 5, preheating third zone section 6, reflow first zone section 7, reflow second zone section 8, cooling section 9 and outlet resistance section 10 are provided. ing.

Each of these zones is unitized and filled with nitrogen gas, and the preheating zone portions 4, 5 and 6 and the reflow zone portions 7 and 8 which are heating zones have a heating unit U having the same structure (see FIG. 1). ). Then, in this heating unit U, the internal airflow is circulated by the sirocco fan 11 for circulating hot air arranged at the lower part, and in the cooling unit constituting the cooling unit 9, the propeller for circulating cold air arranged at the upper part. The internal airflow is circulated by the fan 12. In the following, the lower left side in FIGS. 1 and 2 will be described as the front.

As shown in FIGS. 1 and 3, in each heating unit U, a lower passage 1 is formed in which a suction port 13a is formed and extends rearward in a box-shaped space formed by an inner wall surface Ua thereof.
3 and a rear passage 14 extending upward from a rear position of the sirocco fan 11 are arranged. Also, the rear passage 14
Is provided with a heater 15 for heating the circulating air flow, and a plurality of straightening plates 16 for blowing the air flow heated by the heater 15 downward toward the transport path and ejecting the air flow above the heating unit U. A nozzle 17 is provided. That is, due to the inner wall surface Ua forming the box-shaped space, the lower passage 13 and the rear passage 14, the air flow B sent out rearward from the sirocco fan 11 through the lower passage 13 rises through the rear passage 14 and moves forward. A circulation ventilation path is constructed which descends while facing and is sucked again into the sirocco fan 11.

Here, the current plate 16 has a cross-sectional shape that extends substantially horizontally toward the front and has its front portion bent downward, and extends along the substrate carrying direction A. This straightening plate 16
A plurality of (in this embodiment, two locations) are arranged in the front-rear direction, and the protrusion 16a is locked in a long hole (not shown) formed in the upper surface of the inner wall surface Ua of the heating unit U. It is supported so that it can slide in any direction. Then, as shown in FIG. 3, the front-rear distance L2 between the two straightening vanes 16 is smaller than the front-rear distance L1 between the guide plate 18 provided at the rear upper portion of the heating unit U and the rear straightening vane 16. It becomes smaller, and further than the front-rear distance L2 between both of the straightening vanes 16,
Each straightening vane 16 is arranged such that the front-rear distance L3 between the front straightening vane 16 and the front surface portion Ub of the inner wall surface Ua is reduced. An inner wall surface Ua of the heating unit U is erected on the side of the straightening plate 16 and is isolated so that the hot air flow does not move to the adjacent zone side. Further, in this embodiment, both the straightening vanes 16 have the same sectional shape and are arranged at substantially the same height.

As shown in FIG. 1, the blowing nozzle 17 is constructed by arranging a plurality of bent plate members 19 which are bent in an inverted U-shape in cross section and extend in the front-rear direction in the substrate transfer direction A. A slit-shaped opening is formed on the lower surface side between the bent plate members 19. Further, in the support plate 25 that supports the front end portion and the rear end portion of the bending plate material 19, a cutout portion 25a is formed at a position corresponding to the inner surface side of the bending plate material 19.

In each heating unit U, a pseudo substrate plate 20 is arranged below the transport path in parallel to the substrate transport surface, and the pseudo substrate plate 20 has an upper surface on which the substrate width direction is set. A plurality of standing plate-like portions 21 extending in the direction of the substrate transport direction A are provided at predetermined intervals, and the pseudo substrate plate 20 and the standing plate-like portions 2 are provided.
1, the flow direction of the air flow B ejected from the ejection nozzle 17 is made constant regardless of the presence or absence of the circuit board 2.

Further, the reflow furnace 1 is provided with a plurality of measures for removing the flux. First,
At the entrance / exit where the circuit board 2 is loaded and unloaded, as shown in FIGS. 2 and 4, the air or the like that enters with the circuit board 2 is exhausted by the exhaust duct 30.
A wire net 31 is arranged at a suction port of the exhaust duct 30, and a flux which drops from an inclined lower surface portion of a frame 32 in which the wire net 31 is arranged is received by a tray 33. A frame 34 (see FIG. 5) for collecting the flux dripping from the circuit board 2 is also provided below the entrance tunnel portion which is the entrance to the reflow furnace 1 so that the flux dropped from the frame 34 is received. It can be received in the container 35.

Further, as shown in FIG. 6, a wall tray 36 is arranged on the wall surface of the rear passage 14 in each heating unit U such as in front of the upper edge of the rear passage 14 to remove the flux adhered on the wall surface in the reflow furnace 1. As well as
A receiving tray 37 is provided below the heater 15, and a catalyst 38 is provided above the heater 15 as needed as shown in FIG. 7, so that the catalyst 38 also reduces the flux. It has become.

Further, as shown in FIG. 6, a wire net 39 for flux removal is provided before and after the pseudo substrate plate 20, and in the preheating third zone portion 6, flux is accumulated on the upper part of the blowing nozzle 17. 40 is formed.

Further, as shown in FIG. 8, in the cooling unit 9 as well, a receiving tray 42 for receiving the flux dripping from the cooling fin 41 is arranged below the cooling fin 41, and the lower portion of the cooling unit 9 is provided. Also, a wire mesh filter 43 for flux removal is provided.

As shown in FIG. 9, a cooling fin 44 may be arranged above the cooling unit 9, and a cooling fin tray 45 and a two-layer filter 46 may be provided below the cooling fin 44. The filter 46 may be further composed of three or more layers.

Further, in this reflow furnace 1, the preheating first zone section 4, the preheating second zone section 5, the preheating third zone section 6, the reflow first zone section 7, the reflow second zone section 8, the cooling section 9 are provided. A temperature sensor and a gas suction port (not shown) are provided in the heating unit U and the cooling unit that configure each zone of FIG. Then, the gas sucked from the gas suction port is supplied to the glass wool filter 51 shown in FIG.
The flux is removed by the mesh filter 52, the activated carbon filter 53, etc., and the oxygen concentration analyzer 50 is used for measurement, and the internal heat flow state and temperature are controlled based on the temperature and oxygen concentration data of each zone. Feedback control is performed so that the oxygen concentration and temperature in each zone are within predetermined ranges. In this reflow furnace 1, the oxygen concentration in the preheating zone parts 4, 5, 6 is about 400 ppm.
, The oxygen concentration in the reflow zone 7, 8 is about 100ppm
Is controlled so that the nitrogen gas supply amount and the air supply amount are respectively measured by feedback control by a predetermined amount and mixed, and 200 liters of air-mixed nitrogen gas is supplied into the reflow furnace 1 per minute. .

In FIG. 1, reference numeral 47 is an air-mixed nitrogen gas injection nozzle, and 48 is an exhaust duct. The air-mixed nitrogen gas is injected at all times or during reflow, while exhaust is performed at the end of reflow work. Further, in FIG. 2, reference numeral 55 denotes a lid that covers the upper surface of each unit.

In the above structure, as shown in FIGS. 1 and 3, the hot air flow B from the rear passage 14 moves forward along the upper surface of the inner wall surface Ua as shown in FIG. It flows down while being dispersed in the front-back direction by the current plate 16. Here, each straightening vane 16 has a front-to-back distance L between both straightening vanes 16 rather than a front-to-back distance L1 between a guide plate 18 provided on the rearward upper portion of the heating unit U and the rear straightening vane 16.
2 is smaller, and the longitudinal distance L3 between the front rectifying plate 16 and the front surface portion Ub of the inner wall surface Ua is smaller than the longitudinal distance L2 between the both rectifying plates 16. There is. Therefore, in the horizontal plane of the air flow descending portion where the flow straightening plate 16 is provided, the front side is divided into smaller areas by the flow straightening plate 16, so if there is no flow straightening plate 16, more air flow will flow down toward the front side due to its inertia. ,
Due to the arrangement of the straightening vanes 16, the hot air flow is evenly distributed in the front-rear direction. Then, the hot air stream is jetted toward the circuit board 2 on the carrying path by the blowing nozzles 17 in the direction of the board carrying direction A, whereby the hot air having a uniform wind speed is perpendicular to the entire surface of the circuit board 2. A stream is gushing out,
Good preheating and reflow.

Further, in each unit, since the circulation air passage is formed in which all the hot air streams are raised from the rear side and flowed down from the front side, the air streams B are agitated with each other while passing through the circulation air passage. The temperature and the wind speed are made uniform, and the circuit board 2 on the transfer path is satisfactorily heated by the airflow in which the temperature and the wind speed are made uniform. In addition, the current plate 16
By being jetted in the direction perpendicular to the circuit board 2 by the blowing nozzle 17, the air flow in the substrate transport direction A can be minimized and the flow direction of the internal air flow can be made constant. It is possible to satisfactorily secure the low oxygen concentration and optimum temperature atmosphere of the unit (each zone). Further, even if the hot airflow jetted to the circuit board 2 is reflected and comes into contact with the back surface side of the bent plate material 19 of the blowing nozzle 17, this reflected flow of the bracket plate 25 formed before and after the bent plate material 19 is generated. It is also prevented that hot air flows out from the cutout portion 25a and stays on the back surface side of the blowout nozzle 17.

FIG. 11 shows another embodiment of the present invention. In this embodiment, the straightening vanes 56 are plate members extending only in the vertical direction, and a plurality of straightening vanes 56 are arranged at regular front and rear intervals P. _{It is provided for} each _one . And the current plate 5
As the upper end of 6 is disposed on the front side, which is the downstream side in the lateral flow direction of the hot air flow, it extends upward by a dimension P _{2 from} the upper end of the rear side current plate 56.

A current plate 56 extending upward toward the front side
According to the above, since the hot air flow that tries to flow from the upper part of the rear passage 14 to the front side is evenly distributed in the vertical direction and is guided downward, the hot air flow having a uniform wind velocity is jetted toward the circuit board 2 on the transfer path. As a result, preheating and reflow are performed well. Alternatively, the straightening vanes 56 may have the same vertical length and may be simply shifted in the vertical direction to be arranged at a higher position on the front side straightening vanes.

In the above embodiment, the case where nitrogen gas is used as the inert gas has been described, but a reflow furnace for injecting another inert gas or the like and further a reflow furnace for reflowing in the atmosphere can be easily supported. It goes without saying that you can do it.

[0033]

As described above, according to the present invention, by forming the circulation ventilation path for raising the airflow from one side of the heating zone and lowering it from the other side of the heating zone, the heating condition is different even in the heating means. Even if the airflow is discharged, the airflows are agitated with each other while passing through the circulation airflow path to make the temperature and the air velocity uniform, and the circuit board on the transfer path is well heated by the airflow having the uniform temperature and air velocity. It Further, for example, it is possible to prevent the airflows rising from both sides from converging at the center and disturbing the flow, it is possible to make the flow direction of the internal airflow in the heating zone in the reflow furnace constant, and to set the optimum temperature atmosphere. Can be secured.

Further, by disposing a plurality of straightening vanes for guiding the heat airflow flowing in the lateral direction downward toward the circuit board of the transfer path above the transfer path, the flow direction of the internal airflow, especially the transfer path is improved. The flow direction and flow velocity of the internal air flow in the vicinity can be made constant, and the temperature and air velocity of the air flow that hits the circuit board can be made uniform. Further, by making this straightening plate slidable in the lateral direction orthogonal to the substrate transport direction, the air flow rate of the hot air flow in the lateral direction orthogonal to the substrate transport direction can be easily adjusted, and is orthogonal to the substrate transport direction. By arranging the rectifying plate so that the distance between the adjacent rectifying plates in the lateral direction and the distance between the rectifying plate and the hot air flow descending guide wall surface become smaller toward the downstream side in the lateral flow direction of the hot air flow, The air flow rate of the hot air flow can be made uniform in the lateral direction orthogonal to the substrate transport direction.

Further, by arranging the flow straightening plate on the upper side in the circulation ventilation path as it is arranged on the downstream side in the lateral flow direction of the hot air flow, the air flow rate of the hot air flow can be made uniform and hit the circuit board. The temperature and wind speed of the hot air flow can be made uniform.

Further, a plurality of bent plate members each having a cross-sectional shape of which both edges are bent downward are arranged at regular intervals in the substrate transport direction to form a blowing nozzle, and the blowing nozzle is arranged below the straightening plate. The airflow is blown out toward the circuit board from the slit-shaped opening formed on the lower surface of the blowout nozzle, so that the hot airflow is well dispersed in the board transfer direction and is ejected toward the circuit board. Further, by forming a cutout portion that allows the air flow that has flowed into the back side of the blowing nozzle to flow out, it is possible to prevent the hot air flow from staying on the back side of the blowing nozzle, and to further reduce the oxygen concentration and It is possible to easily secure the optimum temperature atmosphere.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a heating unit of a reflow apparatus according to an embodiment of the present invention.

FIG. 2 is an overall perspective view of the reflow device when the lid is opened.

FIG. 3 is a schematic side cross-sectional view showing the flow of air flow in the heating unit of the reflow apparatus.

FIG. 4 is a perspective view of a main part showing a flux removing structure at an entrance / exit of the reflow apparatus.

FIG. 5 is a perspective view of an essential part showing a flux removing structure at an inlet portion of the reflow apparatus.

FIG. 6 is a perspective view of essential parts showing a flux removal structure of a heating unit of the reflow apparatus.

FIG. 7 is a perspective view of an essential part showing a flux removing structure at an entrance / exit of the reflow apparatus.

FIG. 8 is a perspective view of essential parts showing a flux removal structure of a cooling unit of the reflow apparatus.

FIG. 9 is a perspective view of essential parts showing a flux removal structure of a cooling unit of the reflow apparatus.

FIG. 10 is a perspective view of an essential part showing a flux removing structure of a gas suction section of the reflow apparatus.

FIG. 11 is a schematic side sectional view showing a heating unit in a reflow device according to another embodiment of the present invention.

FIG. 12 is a sectional view of a conventional reflow apparatus.

[Explanation of symbols]

1 reflow furnace 2 circuit board 3 Entrance resistance section 4, 5, 6 Preheating zone part 7,8 Reflow zone part 9 Cooling unit 10 Exit resistance section 11 Sirocco fan (blower) 14 heater 16,56 Current plate 17 blow nozzle 19 Bending member 25 Support member 25a Notch 47 injection nozzle A board transfer direction B air flow U heating unit Ua inner wall surface

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Nakano 1006, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. In-company (56) References: Kaihei 3-43770 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H05K 3/34

Claims (4)

(57) [Claims] 1. A reflow apparatus having a transfer path extending over a plurality of zones, wherein the means for heating an air flow and a passage for guiding the heated hot air flow in a lateral direction above the transfer path and orthogonal to the substrate transfer direction. And a plurality of straightening vanes for guiding the hot air flow passing through this passage downward toward the substrate are provided in a lateral direction orthogonal to the substrate transport direction, and the straightening plates are transverse to the substrate transport direction. A reflow device characterized by being slidable in any direction. 2. A reflow apparatus having a transfer path extending over a plurality of zones, wherein the means for heating an air flow and a passage for guiding the heated hot air flow in a lateral direction orthogonal to the substrate transfer direction above the transfer path. A plurality of straightening vanes are provided in the lateral direction orthogonal to the substrate transport direction, the straightening vanes guiding the hot airflow passing through this passage downward toward the substrate, the distance between the neighboring straightening vanes, and the straightening plate. The reflow device is characterized in that the flow straightening plate is arranged such that a distance between the hot air flow descending guide wall surface and the hot air flow descending guide wall surface becomes smaller toward the downstream side in the lateral flow direction of the hot air flow. 3. A reflow apparatus having a transfer path extending over a plurality of zones, wherein the means for heating an air flow and a passage for guiding the heated hot air flow in a lateral direction above the transfer path and orthogonal to the substrate transfer direction. And a plurality of straightening vanes for guiding the hot airflow that has passed through this passage downward toward the substrate are provided in a lateral direction orthogonal to the substrate transport direction, the straightening vanes being downstream in the lateral flow direction of the hot airflow. A reflow device characterized in that the reflow device is arranged so as to be closer to the side. 4. A reflow apparatus having a transfer path extending over a plurality of zones, said means for heating an air flow, and a passage for guiding the heated hot air flow in a lateral direction orthogonal to the substrate transfer direction above said transfer path. A plurality of straightening vanes are provided in the lateral direction orthogonal to the substrate transport direction, the straightening plates guiding the hot air flow that has passed through this passage downward toward the substrate, and both edges are bent downward. Bending plate materials were provided in a plurality of rows at regular intervals in the substrate transport direction to form a slit-shaped opening, and a blowout nozzle was provided below the flow straightening plate. The end portion of the blowout nozzle flowed into the backside of the blowout nozzle. A reflow device having a cutout portion for allowing airflow to flow to the outside.