JPH1041619A - Reflow soldering equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflow soldering equipment wherein space reduction is enabled by miniaturization, positional deviation of components on a circuit board is little, usage of inert gas or nitrogen gas is little, and thermal efficiency is improved. SOLUTION: A circuit board 50 is rested in the state that the circuit board 50 has been carried by a conveyor 12 at a position of an aperture 40 for heating a thermal insulation board 38. A turning cylinder 26 is rotated around the periphery of the thermal insulation board 38 in the above state, and the circuit board 50 is sequentially heated with a preheating heater 31-33 and a reflow heater 34. At this time, an introducing port and a carrying-out port of a thermal insulation housing 17 constituting a nitrogen gas atmosphere are closed with an entrance side shutter and an exit side shutter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflow soldering apparatus, in particular, by applying cream solder to a soldering site in advance and carrying in and heating a circuit board on which electronic components are mounted at predetermined positions. The present invention relates to a reflow soldering apparatus that melts cream solder and solders and connects electrodes or terminals of electronic components to connection lands on a circuit board.

[0002]

2. Description of the Related Art In order to assemble an electronic circuit, a leadless surface mount type component has been widely used in place of a component with a lead. When assembling an electronic circuit with surface-mounted components, cream solder is applied to the soldering position on the circuit board on which the wiring pattern has been formed in advance by printing, and the electronic component is placed at a predetermined position. Then, gently introduce it into the reflow furnace. Then, the cream solder is melted in a reflow furnace, whereby the electrodes or terminals of the surface mount component are soldered to the connection lands on the circuit board.

FIG. 6 shows a conventional reflow soldering apparatus used for such soldering. The reflow soldering apparatus includes a gantry 1 and a lengthwise direction of the gantry 1 on the gantry 1. The conveyer 2 is arranged so as to extend to the right side. The preheaters 3, 4, 5, and the reflow heater 6 are sequentially arranged on the conveyor 2 along the conveying direction of the conveyor 2. Further, a cooling fan 7 is arranged at a portion on the outlet side of the reflow heater 6.

As described above, the conventional reflow soldering apparatus includes a plurality of preheaters 3, 4, 5, and a reflow heater 6.
Are arranged in series, and the circuit board is connected to the heaters 3, 4,
The lower side of 5 and 6 is heated while being sequentially conveyed by the conveyor belt 2, whereby the cream solder on the circuit board is melted and soldered. That is, the circuit board is moved in the long heating zone while being moved by the conveyor 2, and soldering is performed.

[0005]

A disadvantage of such a conventional reflow soldering apparatus is that the entire length is long and the apparatus becomes large. That is, its total length is at least 2m
And usually had a length of 4 to 5 m. Therefore, there is a disadvantage that the floor area increases.

Further, in such a conventional reflow soldering apparatus, soldering is performed by heating while passing below the preheaters 3, 4, 5 and the reflow heater 6 by the transport conveyor 2, and performing the soldering. The heating was carried out while moving by step 2. Therefore, there is a problem in that the components placed on the circuit board are easily moved by the vibration from the drive source of the conveyor 2 during the transportation, and the displacement is apt to occur. As a result, defective products are generated, and in order to prevent the occurrence of such a connection failure, the dimension between the lands adjacent to each other must be increased, which has been a cause of preventing high-density mounting.

In order to perform high-quality soldering, it is preferable to perform soldering in a gas atmosphere in which the solder is not oxidized, such as an inert gas or a nitrogen gas. However, according to the conventional reflow soldering apparatus, a carry-in port and a carry-out port of the circuit board are provided at both ends, respectively. To fill with active gas or nitrogen gas, a large amount of inert gas or nitrogen gas must be supplied, and there is a problem that the consumption of such gas is extremely large.

Further, according to such a conventional reflow soldering apparatus, since the preheating heaters 3, 4, 5, and the reflow heater 6 are arranged in series on a plane, these heaters 3 4, 5, and 6, there is a problem that heat efficiency is low due to heat interference and heat dispersion, and power consumption is large.

As a result of various tests, the inventor of the present application has found that a soldering method in which a substrate is stationary and a heater is moved around a stationary substrate and soldered is used to solve all of the above problems. The present invention has been completed based on the findings described above.

Accordingly, an object of the present invention is to provide an energy-saving reflow soldering apparatus which is small in size, hardly displaces components during soldering, uses a small amount of gas which does not easily oxidize solder, and has excellent thermal efficiency. It is intended for.

[0011]

SUMMARY OF THE INVENTION The present invention relates to a reflow soldering apparatus in which cream solder is applied, and a circuit board on which electronic components are mounted is heated by a heater to perform soldering. The present invention relates to a reflow soldering apparatus comprising a mold-type heater, wherein the circuit board in a stationary state is heated by the heater to melt and solder the cream solder.

Another invention is to apply a cream solder to a soldering position in advance, and to carry in and heat a circuit board on which electronic components are mounted at a predetermined position, thereby melting the cream solder to form the electronic component. In a reflow soldering apparatus configured to connect an electrode or a terminal of a component to a connection land on a circuit board, a heat insulating cover is provided so as to penetrate through the heat insulating cover, and the circuit is disposed in the heat insulating cover. Transport means for moving the board and holding the circuit board in a stationary state at the time of heating, and a plurality of heaters arranged on an outer peripheral portion of the heat insulating cover and arranged so as to be movable in a circumferential direction of the heat insulating cover. , Each of which sequentially moves the plurality of heaters to a heating portion of the heat insulating cover to change the temperature inside the heat insulating cover. Relates reflow soldering apparatus is characterized in that so as to heat the plate.

[0013] An entrance and an exit of the circuit board may be provided at positions opposite to each other in the carrying direction of the carrying means.

A shutter may be provided at each of the entrance and the exit of the circuit board, and the soldering may be performed in a gas atmosphere in which the solder is hardly oxidized.

[0015]

FIG. 1 shows an entire configuration of a reflow soldering apparatus according to an embodiment of the present invention. The reflow soldering apparatus has a vertically long base 10. On the gantry 10, a carry-in conveyor 11, an intermediate conveyor 12, and a discharge conveyor 13 are arranged in series with each other along the longitudinal direction.

A heat insulating housing 17 is provided on the gantry 10 so that the intermediate conveyor 12 enters the interior of the gantry 10 and at an intermediate position thereof. One end of the heat-insulating housing 17 is an introduction port 18, and a carry-out port 19 is provided at a position opposite to the introduction port 18 of the heat-insulation housing 17. And these inlets 18 and outlets 19
Has an entrance side shutter 20 and an exit side shutter 21 respectively.
And are attached. A heating zone 22 is formed between the entrance side shutter 20 and the exit side shutter 21 and inside the heat insulating housing 17.

In the heating zone 22, a rotating cylinder 26 is rotatably arranged as shown in FIGS. On the inner peripheral side of the rotary cylinder 26, partition plates 27, 2 are provided at 90 ° intervals.
8, 29 and 30 are respectively attached. Then, a first preheater 31 is attached between the partition plates 30 and 27. A second preheater 32 is mounted between the partition plates 27 and 28. Further, a third preheater 33 is attached between the partition plates 28 and 29. A reflow heater 34 is mounted between the partition plates 29 and 30. These heaters 31 to 34 are connected to the rotating cylinder 26.
At the same time, the outer peripheral side of the intermediate conveyor 12 is rotated.

The inside of the rotating cylinder 26 is shown in FIGS.
As shown in FIG. 5, a cylindrical heat insulating plate 38 having a part in the circumferential direction is provided. And this heat insulating plate 38
A frame 39 is attached to a part of the frame 39, and a heating opening 40 is formed inside the frame 39.

The outlet 19 of the heat-insulating housing 17
As shown in FIG. 1, an opening 45 is formed outside the shutter 21 on the outlet side, and a cooling fan 46 is mounted outside the opening 45.

As described above, in the reflow soldering apparatus according to the present embodiment, the preheating heaters 31 to 33 and the reflow heater 34 are provided in the respective regions partitioned by the partition plates 27 to 30 on the inner peripheral surface of the rotating cylinder 26. The structure is arranged. Since these four heaters 31 to 34 are partitioned by the partition plates 27 to 30, heat interference between the heaters 31 to 34 having a temperature difference is small, and a structure capable of maintaining a predetermined temperature almost certainly is provided. ing.

Further, the reflow soldering apparatus includes a heat insulating plate 38 provided with a heating opening 40 at an upper portion, and heats the circuit board 50 on the intermediate conveyor 12 only by a heater located at the heating opening 40 of the heat insulating plate 38. I try to make it. Therefore, there is no influence of the heat of other heaters at that time. Further, since the heating zone 22 is very narrow, the heat dispersion is narrow, the thermal efficiency is improved, and power saving is achieved.

Next, the operation of soldering by such a reflow soldering apparatus will be described. The circuit board 50 on which the reflow soldering is performed is made of an insulating material, a wiring pattern formed by etching a copper foil is formed on the surface thereof, and a connection land is formed by a copper foil at a soldering position. . Then, cream solder is applied in advance to the soldering position of such a circuit board by a printing technique, and various surface-mounted electronic components are mounted thereon.

The circuit board 50 is introduced by the carry-in conveyor 11 through the inlet 18 of the heat insulating housing 17. At this time, the entrance side shutter 20 is opened,
The circuit board 50 is moved from the carry-in conveyor 11 to the intermediate conveyor 1
Transferred to 2. When the circuit board 50 is introduced into the heat insulating housing 17, the entrance-side shutter 20 closes.

When the circuit board 50 conveyed and introduced by the intermediate conveyor 12 is located below the heating opening 40 of the heat insulating plate 38 of the heat insulating housing 17, the intermediate conveyor 12 stops. The rotating cylinder 26 is indicated by an arrow 52 in FIG.
Is rotated clockwise as shown in FIG.
The preheating heaters 31, 32, 3
3. The reflow heaters 34 are sequentially located.

Accordingly, the circuit board 50 stationary on the intermediate conveyor 12 is heated by the preheaters 31, 32, 33 and the reflow heater 34 in order. As a result, the cream solder previously applied on the circuit board 50 is melted, and the cream solder solders the electrodes or terminals of the surface mount component to the connection lands on the circuit board 50.

Thereafter, the circuit board 50 is moved to the carry-out port 19 side of the heat insulating housing 17 by the intermediate conveyor 12, the outlet-side shutter 21 is opened, and the circuit board 50 is transferred to the carry-out conveyor 13. When passing through the carry-out port 19 of the heat-insulating housing 17, it is cooled by the cooling fan 46 through the opening 45, and the molten solder is solidified and carried out.

As described above, according to the reflow soldering apparatus according to the present embodiment, the preheaters 31, 32, and 33 and the reflow heater 34 are separated from each other by the partition plates 27 to 30 inside the rotary cylinder 26. Since it is arranged and is configured by a rotatable movable heater, the heating zone in the heat insulating housing 17 can be significantly reduced in size. That is, as compared with the conventional reflow soldering apparatus, the dimension in the length direction is reduced to 1/3.
The following can be achieved, thereby achieving a significant space saving.

According to the present embodiment, the circuit board 50
Is the heater 3 in a state where it is stationary on the intermediate conveyor 12.
The circuit board 50 is sequentially heated by 1 to 34, and the circuit board 50 is kept stationary during heating.
Accordingly, there is no possibility that the components mounted on the circuit board 50 will be displaced by vibration, and the occurrence of poor connection will be greatly reduced. In addition, since the displacement of components is reduced, high-density mounting can be performed by reducing the distance between the connection lands.

Further, such a soldering apparatus has a structure in which the inlet 18 and the carry-out port 19 of the heat insulating housing 17 are closed by the inlet shutter 20 and the outlet shutter 21, respectively, and are shielded from the outside air. Therefore, when an inert gas or a nitrogen gas is used in such a heat insulating housing 17, the usage of these gases is significantly reduced. Therefore, it is possible to efficiently perform soldering in a state where the oxygen concentration is extremely low.
According to the soldering in an inert gas or nitrogen gas atmosphere, the solder is hardly oxidized, so that the solder quality is remarkably improved. In addition, according to the soldering in an inert gas or nitrogen gas atmosphere, the amount of the flux used is reduced, and the step of cleaning and removing the flux can be simplified or omitted. As a result, it is possible to reduce the amount of a cleaning agent that has an adverse effect on the environment, particularly, fluorocarbon and the like, or not to use it at all.

Further, such a reflow soldering apparatus is
The preheating heaters 31 to 34 are arranged at 90 ° intervals in the circumferential direction inside the rotary cylinder 26, and the heat insulating housing 17 is shielded from the outside air. And the thermal efficiency is greatly improved due to the small capacity of the heating area, and power saving is achieved.

[0031]

According to the present invention, the heater is constituted by a movable heater, and the stationary circuit board is heated by the heater to melt the cream solder and solder it.

Therefore, according to the present invention, it is possible to heat the circuit board in a stationary state and perform soldering, thereby preventing components on the circuit board from being displaced by vibration and preventing poor connection. Thus, high-density mounting can be performed.

Another aspect of the present invention provides a heat insulating cover, a transfer means for penetrating the inside of the heat insulating cover, moving the circuit board into the heat insulating cover, and holding the circuit board in a stationary state at the time of heating; A plurality of heaters arranged on an outer peripheral portion of the cover and movably arranged in a circumferential direction of the heat insulating cover, respectively. The temperature in the cover is changed.

Therefore, the displacement of the components is prevented, and the plurality of heaters are arranged so as to be movable in the circumferential direction of the heat insulating means. Therefore, the size of the apparatus can be significantly reduced, thereby saving the apparatus. Space is achieved.

According to the configuration in which the shutter is provided at each of the entrance and the exit of the circuit board, and the soldering is performed in a gas atmosphere in which the solder is not easily oxidized, the heating atmosphere can be shut off from the outside air. As a result, soldering in an inert gas or nitrogen gas becomes possible, and the amount of use of the inert gas or nitrogen gas can be greatly reduced. In addition, since heating is performed in a closed atmosphere, thermal efficiency is improved,
Power saving is achieved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the overall configuration of a reflow soldering apparatus.

FIG. 2 is a vertical sectional view in a direction perpendicular to a transport direction of a circuit board.

FIG. 3 is a perspective view of a rotating cylinder.

FIG. 4 is an exploded perspective view of the heat insulating plate.

FIG. 5 is a perspective view showing an internal structure of a main part of the soldering device.

FIG. 6 is a plan view showing a conventional reflow soldering apparatus.

[Explanation of symbols]

1 ‥‥ stand, 2 ‥‥ conveyor, 3、３5 preheater, 6 ‥‥ reflow heater, 7 ‥‥ cooling fan, 10 ‥
{Mounting stand, 11} Carry-in conveyor, 12} Intermediate conveyor, 13} Carry-out conveyor, 17} Insulated housing, 18} Inlet, 19} Outlet, 20} Inlet shutter, 21} {Exit shutter, 22} Heating zone, 26} Rotating cylinder, 27-30} Partition plate, 31
~ 33 ‥‥ preheating heater, 34 ‥‥ reflow heater, 38
‥‥ Insulation board, 39 ‥‥ frame, 40 ‥‥ heating opening,
45 ° opening, 46 ° cooling fan, 50 ° circuit board, 52 ° arrow

Claims (4)

[Claims] 1. A reflow soldering apparatus in which cream solder is applied and a circuit board on which electronic components are mounted is heated by a heater and soldered, wherein the heater is constituted by a movable heater. A reflow soldering device, wherein the circuit board in a stationary state is heated by the heater to melt the solder and solder it. 2. A method of applying cream solder to a soldering position in advance and loading and heating a circuit board on which an electronic component is mounted at a predetermined position, thereby melting the cream solder to form an electrode or an electrode of the electronic component. In a reflow soldering apparatus in which terminals are connected to connection lands on a circuit board, a heat insulating cover is provided so as to penetrate through the heat insulating cover, and the circuit board is moved into the heat insulating cover. Transport means for holding the circuit board in a stationary state at the time of heating, and a plurality of heaters arranged on an outer peripheral portion of the heat insulating cover and movably arranged in a circumferential direction of the heat insulating cover. Then, the circuit board is heated while changing the temperature inside the heat insulating cover by sequentially moving the plurality of heaters to the heating portion of the heat insulating cover. A reflow soldering apparatus characterized in that: 3. The reflow soldering apparatus according to claim 2, wherein an entrance and an exit of the circuit board are provided at positions opposite to each other in the carrying direction of the carrying means. 4. The reflow soldering apparatus according to claim 3, wherein shutters are provided at an entrance and an exit of the circuit board, respectively, and the soldering is performed in a gas atmosphere in which the solder is hardly oxidized. .