JP4538367B2 - Reflow furnace - Google Patents

Description

  The present invention relates to a reflow furnace for heating and soldering a circuit board on which electronic components are mounted.

  The reflow furnace is used for soldering electronic components mounted on a circuit board using a solder paste. A reflow furnace generally has a pair of left and right rails that continuously extend from the entrance to the exit of the furnace as a transport means for transporting a circuit board, and an endless chain that is guided and moved by the rails. The circuit board is transferred (Patent Document 1). In other words, the endless chain typically has pins arranged opposite to each other, and the substrate is transported while being locked to the left and right pins. This pair of left and right rails is typically fixed to one rail and the other rail is movable so that it can be applied to various sizes of boards. Can be adjusted.

  Patent Document 2 discloses a typical structure of a recent reflow furnace. As disclosed in Patent Document 2, a recent reflow furnace has a heating section divided into a plurality of heating zones, and the circuit board is preheated and main heated by passing through the plurality of heating zones. To do. In such a reflow furnace, each of the plurality of heating zones constituting the heating unit has a suction port in order to circulate the atmospheric gas in each zone, and each of the heating zones is provided by a heat source and a fan provided in each heating zone. The temperature is controlled for each heating zone. Further, as disclosed in Patent Document 2, a reflow furnace provided with a cooling unit after the heating unit is also known, and the circulation of the atmospheric gas is performed through the air outlet and the suction port provided in the cooling unit. Done.

As is known, the reflow furnace has a problem that the inside is contaminated by the flux. In other words, the solder paste used for soldering electronic components is a viscous soldering material in which flux and powder solder are mixed, and flux is a solid component such as pine resin, thixotropic agent, and activator. It is dissolved in and adjusted to an appropriate viscosity. Since the solder paste flux is vaporized by being heated in the reflow furnace, there is a problem that the interior of the reflow furnace is contaminated by the vaporized flux.
Japanese Patent Laid-Open No. 9-69681 JP-A-2005-79466

  In the maintenance of the reflow furnace, cleaning of the furnace such as removal of flux adhered to the wall surface and inspection or replacement of the heater as the heat source are performed.To expose this, in order to expose the wall surface and the heat source, etc. It has been necessary to remove the fixed rail and / or the movable rail that interfere when removing the atmospheric gas circulation unit including the blowout port and the suction port. As described above, the fixed rail and the movable rail are long members continuously extending from the entrance to the exit of the furnace, and the operation of removing such a long fixed rail and / or the movable rail from the reflow furnace. Is cumbersome and time-consuming, and the maintenance work for the reflow furnace has been complicated.

  The objective of this invention is providing the reflow furnace which can reduce a maintenance operation | work.

According to the present invention, such a technical problem is
The circuit board on which the electronic component is mounted is heated and soldered while being transported by the transport means guided by the pair of rails spaced apart in the width direction in the furnace, and the pair of rails according to the width dimension of the circuit board Is a reflow furnace displaceable in the width direction of the furnace,
An atmospheric gas blowing / suction unit having an atmospheric gas outlet and an inlet for circulating the internal atmospheric gas of the reflow furnace includes a side member positioned at a side of the reflow furnace, and a width of the reflow furnace. This is achieved by providing a reflow furnace characterized in that it is divided into a central member located in the central portion in the direction, and these side members and central member are independently removable from the reflow furnace.

  That is, the atmospheric gas blowing / suction unit constituting the internal structure of the reflow furnace is divided into a side member and a central member, and these side members and the central member are individually removable, The central member can be removed and the side members can be removed by moving the pair of rails in the width direction of the furnace. Therefore, maintenance work can be performed without removing the long rails when performing maintenance on the reflow furnace.

  In a preferred embodiment of the present invention, the atmospheric gas blowing / suction unit has a ventilation path frame provided with an internal passage for guiding the air generated by the fan, and the ventilation path frame communicates with the side member. An upper end opening that communicates with the central member, and the side member is removable by being displaced to a central portion in the width direction of the reflow furnace. A suction port for sucking the atmospheric gas and a blower outlet for discharging the atmospheric gas are formed. By adopting such a configuration, the side member can be removed without interference with the rail by displacing the side member to the center in the width direction of the furnace after removing the central member.

  The application of the present invention may be limited to the preheating zone, but may be applied to the cooling zone in the main heating zone or a reflow furnace equipped with a cooling unit.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram for explaining an outline of the reflow furnace of the embodiment. The reflow furnace 1 shown in FIG. 1 has a heating unit 2 as in the conventional case, and has a cooling unit 3 although it is not essential. In this embodiment, the heating unit 2 includes four preheating zones 2A to 2D and two main heating zones 2E and 2F. Moreover, although the cooling part 3 is comprised by the two cooling zones 3A and 3B, the number of zones of the heating part 2 and the cooling part 3 is arbitrary.

  FIG. 2 is a schematic view of the lower part of the reflow furnace 1 as viewed from above. Referring to FIGS. 1 and 2, the reflow furnace 1 also has a transfer means 4 for transferring the circuit board in one direction from the inlet 1a to the outlet 1b. The transfer means 4 has a fixed rail 4a and a movable rail 4b as in the conventional case, and the fixed rail is adapted to match the width of the circuit board by displacing the movable rail 4b in the width direction of the reflow furnace 1. The interval between 4a can be adjusted.

  The circuit board on which the electronic components are mounted via the solder paste is conveyed from the inlet 1a toward the outlet 1b while being engaged with a pinless endless chain (not shown) that moves along the rails 4a and 4b. After the substrate is preheated in the process, the main heating is performed to perform soldering, and after cooling, the substrate is taken out of the furnace.

  Returning to FIG. 1, the preheating zones 2 </ b> A to 2 </ b> D and the main heating zones 2 </ b> E and 2 </ b> F basically have the same configuration and are arranged above and below the conveying unit 4 and driven by a motor 5. 6, a heater 7, and an atmospheric gas blowing / suction unit 8. The cooling zones 3 </ b> A and 3 </ b> B include a fan 6 driven by a motor 5 and an atmospheric gas blowing / suction unit 8.

  With reference to FIG. 2, the atmospheric gas blowing / suction unit 8 is independent for each of the zones 2 </ b> A to 2 </ b> F, 3 </ b> A, 3 </ b> B of the reflow furnace 1. A pair of left and right side outlets 9, 9 located on both sides and a pair of side outlets 9, 9 and a central outlet / suction part 10 sandwiched between the pair of side outlets 9, 9. Both the central outlet / suction part 10 can be easily detached.

  FIG. 3 shows the ventilation path frame 11 provided in each of the preheating zones 2A to 2D and the main heating zones 2E and 2F. The ventilation path frame 11 is fixed to the machine frame of the reflow furnace 1 by using bolts inserted through the attachment portion 11a. With reference to FIG. 3, the ventilation path frame 11 has a horizontal box 13 having a fan installation hole 12 at the base thereof, and the fan 6 described above is disposed in the fan installation hole 12. The ventilation path frame 11 further includes a vertical box 14 that rises upward at a portion located at the end of the horizontal box 13, that is, at the side of the reflow furnace 1. The pair of left and right vertical boxes 14 have inclined opposed surfaces 14a that are inclined so as to expand upward on their mutually facing surfaces, and the elongated opposed surfaces 14a have first elongated openings extending vertically. A plurality of 15 are formed side by side. FIG. 4 is a plan view of the ventilation path frame 11 as viewed from above. As can be seen from FIG. 4, the upper end surfaces of the pair of left and right vertical boxes 14 have second openings 16 that are largely open upward.

  That is, in the ventilation path frame 11 shown in FIG. 4, the circumferential inlet 20 that opens facing the fan installation hole 12 passes through the inside of the horizontal box 13, then passes through the vertical box 14, and opens to the inclined facing surface 14 a. The first opening 15 communicates with the second opening (upper end opening) 16 opened upward.

  The ventilation path frame 11 has a pair of guide rails 21 connecting the upper end of one vertical box 14 and the upper end of the other vertical box 14, and the pair of guide rails 21, 21 are connected to one end of the vertical box 14. Connected to the other end. In other words, the pair of guide rails 21, 21 extends in the horizontal direction across the pair of vertical boxes 14, 14 at the upper end of the ventilation path frame 11.

  As best understood from FIG. 3, a box-shaped side member 23 constituting the side blowing portion 9 is placed on the upper ends of a pair of vertical boxes 14 on the ventilation path frame 11, and this side member. 23 is opened downward and communicates with the upper end opening 16 of the vertical box 14, and a number of small holes 24 are formed in the upper plate 23 a. FIG. 5 is a view corresponding to FIG. 3 and shows a state in which the side member 23 is installed on the upper end opening (second opening) 16 of the vertical box 14 shown in FIG.

  The left and right side members 23 are guided by the guide rails 21, 21 and are movable toward the center of the ventilation path frame 11, and are separated from the guide rails 21 at the central portion of the ventilation path frame 11 to be side members. 23 can be removed. In other words, each side member 23 is detachable with respect to the guide rail 21 at the central portion in the longitudinal direction of the guide rail 21.

  A central member 27 shown in FIGS. 6 and 7 is accommodated in the central space 26 (FIGS. 3 to 6) sandwiched between the pair of left and right vertical boxes 14 of the ventilation path frame 11, and this central member 27 is described above. It is a member constituting the central outlet / suction unit 10. FIG. 6 is a perspective view of the central member 27 as viewed from obliquely above, and FIG. 7 is a perspective view of the central member 27 as viewed from obliquely below. The central member 27 has a structure in which a plurality of box-shaped box members 28 are arranged side by side with a predetermined interval 29 facing downward.

  As can be seen from FIG. 6, a slit-like suction port extending in the width direction of the reflow furnace 1 is formed on the upper surface of the central member 27, and a chevron box member 28 is formed between the adjacent gaps 29. A large number of small holes 30 formed on the upper surface of the substrate are formed. The central member 27 has an inclined surface 27a and a third opening 32 corresponding to the inclined opposing surface 14a and the first opening 15 of the above-described ventilation path frame 11 on both sides thereof. The opening 32 and the first opening 15 are in communication with each other.

  The reflow furnace 1 is fixed to the machine frame using bolts in which the ventilation path frame 11 is inserted in the upper area of the heater 7 at the upper and lower sides or at least the lower side of each of the zones 2A to 2F, 3A and 3B. The fan 6 is disposed in the fan installation hole 12 of the ventilation path frame 11. Then, a side member 23 constituting the side blowing portion 9 and a central member 27 constituting the central blowing / suction portion 10 are installed on the ventilation path frame 11.

  When the fan 6 is driven by the motor 5, the atmospheric gas (inert gas such as nitrogen gas or air) in each zone 2 </ b> A to 2 </ b> F, 3 </ b> A, 3 </ b> B is sucked through the gap 29 of the central member 27. The atmosphere gas sent out passes through the inside of the horizontal box 13 and the vertical box 14 forming the internal passage of the ventilation path frame 11 from the circumferential inlet 20, and faces the first opening 15 of the inclined facing surface 14 a of the vertical box 14 and the first opening 15. The upper surface of the side member 23 that enters the inside of the central member 27 through the third opening 32, is discharged into the zone through the small hole 30 formed in the upper surface of the central member 27, and is disposed on the vertical box 14. It is discharged into the zone through the small holes 24 formed in.

  When maintaining the reflow furnace 1, when the movable rail 4 b is located at a position where the movable rail 4 b interferes with the central blowing / suction unit 10, first, the movable rail 4 b is moved to the upper side of the side part of the reflow furnace 1, that is, the side blowing part 9. To move. Thereby, as shown in FIG. 8, the central member 27 constituting the central outlet / suction unit 10 can be removed, and the central member 27 can be cleaned outside the reflow furnace 1. As a result of this series of operations, the reflow furnace 1 loses the central member 27 as shown in FIG. 3, and the bottom of the ventilation path frame 11, that is, the heater 7 is exposed, and the heater 7 is inspected and replaced in this state. be able to.

  Next, as shown by arrows in FIGS. 3 and 8, the side member 23 can be removed by sliding the pair of left and right side members 23 constituting the side blowing portion 9 to the center. Thereby, the side part member 23 which comprises the side part blowing part 9 can be cleaned out of the reflow furnace 1. FIG.

  As can be seen from the above description, the reflow furnace 1 can be cleaned and the heater 7 can be replaced without removing the fixed rails 4a and 4b constituting the circuit board transport means 4, so that the reflow furnace 1 Maintenance work can be greatly reduced.

It is explanatory drawing which looked at the inside of the reflow furnace of an Example from the side. It is explanatory drawing which looked at the lower part of the reflow furnace of FIG. 1 from the circuit board conveyance path. It is a perspective view of the ventilation path flame | frame installed in each zone of the reflow furnace of FIG. It is a top view of the ventilation path frame of FIG. It is a top view of the state which installed the side part member (side part blowing part) in the ventilation path frame of FIG. FIG. 4 is a perspective view of a central outlet / suction member installed in a central region of the ventilation path frame of FIG. 3. It is the figure which looked at the center blowing and suction member of FIG. 6 from diagonally downward. It is a figure relevant to FIG. 3 for demonstrating removal of a center blowing and suction member, and subsequent removal of a side part member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reflow furnace 2 Heating part 2A-2D Preheating zone 2E, 2F Main heating zone 3 Cooling part 4 Conveying means 4a Fixed rail 4b Movable rail 5 Motor 6 Fan 7 Heater 8 Atmospheric gas blowing / suction unit 9 Side blowing part 10 Center Blowing / suction part 11 Ventilation path frame 12 Fan installation hole 13 Horizontal box 14 Vertical box 14a Inclined opposing surface 21 Guide rail of atmospheric gas blowing / suction unit 23 Side member constituting side blowing part 24 Small hole in side part (Side outlet)
26 Central space 27 Central member 27a Inclined surface 28 Mountain-shaped box member 29 Clearance (slit: inlet)
30 small hole (central outlet)

Claims (4)

The circuit board on which the electronic component is mounted is heated and soldered while being transported by the transport means guided by the pair of rails spaced apart in the width direction in the furnace, and the pair of rails according to the width dimension of the circuit board Is a reflow furnace displaceable in the width direction of the furnace,
An atmospheric gas blowing / suction unit having an atmospheric gas outlet and an inlet for circulating the internal atmospheric gas of the reflow furnace includes a side member positioned at a side of the reflow furnace, and a width of the reflow furnace. A reflow furnace characterized in that it is divided into a central member located at the center in the direction, and these side members and the central member are individually removable from the reflow furnace. The atmospheric gas blowing / suction unit has a ventilation path frame with an internal passage for guiding the air generated by the fan,
The ventilation path frame has an upper end opening communicating with the side member and a first opening communicating with the central member,
The side member can be removed by displacing in the center part in the width direction of the reflow furnace,
The reflow furnace according to claim 1, wherein the central member is formed with a suction port for sucking atmospheric gas in the furnace and a blower outlet for discharging atmospheric gas.   The reflow according to claim 2, wherein the reflow furnace has a plurality of preheating zones each including a heating source and a fan, and the ventilation path frame is detachably provided in each of the plurality of preheating zones. Furnace. It has a plurality of preheating zones equipped with a heating source and a fan, and heats and solders the circuit board on which electronic components are mounted by transporting means guided by a pair of rails separated in the width direction in the furnace. And a reflow furnace in which at least one of the pair of rails is displaceable in a width direction in the furnace,
A ventilation path frame provided with an internal passage that is disposed for each of the plurality of preheating zones and that is detachable from a machine frame of the reflow furnace and that guides air generated by a fan;
The ventilation path frame has a horizontal box with a fan installation hole at the base thereof, and a pair of vertical boxes rising from both ends of the horizontal box is provided with a side member with a blower outlet at the upper end opening. In addition, a plurality of side-by-side first openings that are inclined so as to expand toward the upper end of the vertical box and communicate with the internal passage of the vertical box are provided on opposite surfaces of the vertical box. With an inclined facing surface,
The central member that can be installed in the space sandwiched between the pair of vertical boxes has a plurality of box members each having an inclined surface that is formed with a second opening that faces the inclined opposing surface and communicates with the first opening. The plurality of box members are arranged side by side at a distance from each other, a suction port is formed in a gap between adjacent box members, and an air outlet is formed on the upper end surface of the box member. ,
The ventilation frame is provided with a guide rail installed between the upper ends of the pair of vertical boxes, and the side member guided by the guide rail can be displaced toward the center in the width direction of the reflow furnace. And the reflow furnace characterized by being removable in the center part of the width direction of this reflow furnace.

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