JPH1098262A - Reflowing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat a printed board, without increasing the entire length of a reflowing apparatus, even for many production tacts by providing a printed board-heating part vertically movable to the board. SOLUTION: A printed board 1 carried by a conveyer 2 stops approximately at the center of a reflowing apparatus. A door 13 is closed, heaters 7, 8 at the upper and lower faces are energized to start heating, such that the heaters 7, 8 are comparatively distant from the board 1 and designed to gradually raise the temp. along a preheating temp. curve, and after a time at required preheating temp., the heaters 7, 8 are moved to the board 1 by motors 9, 10 for heating the board 1 up to a reflow temp. After the reflow temp. of the board 1 has been reached, the door 13 opens to carry the board 1 out and cool the board it. Even with numerous production tacts, the printed board can be heated up to the required temp., without increasing the entire length of the reflowing apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflow apparatus for connecting a pattern electrode of a printed circuit board to an electrode of an electronic component by heating and melting cream solder in an electronic component mounting process.

[0002]

2. Description of the Related Art In recent years, miniaturization and high-density mounting of electronic components have been rapidly progressing, and even in a reflow apparatus, high precision and stabilization of heating conditions have been required for mounting fine and fine electronic components. It is detached. Hereinafter, a conventional reflow apparatus will be described.

FIG. 4 schematically shows the structure of a conventional reflow apparatus. In FIG. 4, 1 is a printed circuit board, 2
Is a conveyor, and 3 is a motor for driving the conveyor. Reference numerals 4a, 4b, and 4c denote heaters for heating, which are provided above the printed circuit board. 5a,
5b and 5c are lower surface heaters for heating the lower surface of the printed circuit board. 4a, 4b, 4c, 5a, 5b, and 5c are temperature-controlled as a preheating section and a reflow section, respectively, and an optimum temperature profile for reflow is obtained. 6 is a cooling device after reflow.

[0004] The operation of the reflow apparatus configured as described above will be described below. First, the conveyor 2 is continuously rotating, and electronic components are mounted on the printed circuit board 1 and are carried in. FIG. 5 shows a temperature profile for reflow, in which heaters 4a, 4b, 4c, 5a, 5a
b and 5c are set according to the size of the printed circuit board 1 and the conveying speed of the conveyor 2 so that the surface temperature of the printed circuit board 1 rises to a predetermined temperature. In this way, reflow is performed while continuous conveyance is performed.

[0005]

However, in the above-described conventional configuration, the transfer tact of the conveyor 2 is determined by the production tact of mounting the printed circuit board 1. For this reason,
If the production volume increases, it is necessary to speed up the transport tact,
In this connection, it is necessary to increase the temperatures of the heaters 4 and 5. However, the rapid heating has an adverse effect on the electronic components and also has an adverse effect on the uniformization of the surface temperature of the printed circuit board 1. For this reason, the reflow device increases the overall length and the number of heaters so that the surface temperature of the printed circuit board 1 rises to a predetermined temperature without increasing the heater temperature even if the conveyor speed is increased. I have to. However, if the production is small,
Such a reflow device wastes factory space and, on the other hand, does not allow the printed circuit board to be heated to the required temperature if the production exceeds the temperature capacity of the reflow device.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a reflow apparatus capable of determining the size of equipment according to a production amount.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a reflow device in a mounting process of an electronic component in a step of heating and melting cream solder to connect a pattern electrode of a printed circuit board and an electrode of the electronic component. A heating unit for heating the printed circuit board is provided so as to be vertically movable with respect to the printed circuit board.

According to the present invention, by varying the distance between the heater and the printed circuit board, the temperature of the printed circuit board can be controlled to an optimum temperature for reflow. Even in this case, the printed circuit board can be heated to a required temperature without increasing the overall length of the reflow device.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a reflow apparatus in an electronic component mounting step of heating and melting cream solder to connect a pattern electrode of a printed circuit board and an electrode of an electronic component. The heating section for heating the printed circuit board is provided so as to be vertically movable with respect to the printed circuit board. By changing the distance between the heater and the printed circuit board, the temperature of the printed circuit board is reflowed. It is possible to heat the printed circuit board to the required temperature without increasing the overall length of the reflow device, even if the production tact is large, as in the conventional device. .

According to a second aspect of the present invention, a heater or a hot air blower is used for the heating section, and has the same function as the first aspect of the invention. The invention according to claim 3 uses a heater and a hot air blower in combination with the heater, and the hot air blower is provided above the heater,
It is characterized in that hot air is blown through a hole made almost perpendicularly to the heater, and when heating only with the heater, if there is a difference in temperature absorption due to the difference in the color of the printed circuit board, the hot air By applying heating, the temperature of the printed circuit board can be made uniform.

[0011] The invention according to claim 4 is characterized in that the heating section is provided so as to increase the temperature at a position distant from the printed circuit board and approach the printed circuit board after reaching the preheating temperature. In addition to preventing the occurrence of failure of electronic components due to rapid heating, even if the production tact is large as in the conventional device, it is possible to heat the printed circuit board to the required temperature without increasing the overall length of the reflow device. You can do it.

According to a fifth aspect of the present invention, in the reflow device, the conveyer which drives the printed circuit board to be stopped after being carried into a substantially central portion of the reflow device and then carried out after heating, and when the reflow device is heated, It is equipped with a door that seals the entrance and exit of the printed circuit board, and the printed circuit board is heated while stopped in the reflow device, so it is easy to change the temperature setting and production tact. Can respond. Further, since the reflow device is shut off from the outside air by the door during heating, the temperature can be raised efficiently.

According to a sixth aspect of the present invention, a plurality of the reflow devices are connected in series, and a stocker capable of stocking more printed circuit boards than the number of the reflow devices is provided on the carry-in side, and the printed circuit boards are one by one. It is a reflow system characterized by carrying out sorting and loading into the reflow device and starting, stopping and unloading reflow at the same time.The number of connected units can be determined according to the production volume, without occupying wasteful space, It can easily respond to changes in production volume and production tact.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a printed circuit board,
2 is a conveyor, 3 is a motor for driving the conveyor, 7 is an upper heater for heating the printed circuit board 1 from the upper surface, and 8 is a lower heater for heating the printed circuit board 1 from the lower surface. Reference numerals 9 and 10 denote motors and drive units for raising and lowering the respective heaters. Guides 11 and 12 are provided on opposite sides thereof, and support one end of the heaters. A door 13 is driven by an actuator 14.

The operation of the reflow apparatus configured as described above will be described. First, the printed circuit board 1 is carried in by the conveyor 2, and stops at almost the center of the reflow device. Next, the door 13 is closed, the heaters 7 and 8 on the upper surface and the lower surface are energized, and heating is started. At this time, the positions of the heaters 7 and 8 on the upper surface and the lower surface are relatively far from the printed circuit board 1 and are designed to draw a preheating temperature curve for gradually increasing the temperature. After a certain period of time at the required preheating temperature, the heaters 7 and 8 are
, And is heated until the printed circuit board 1 reaches a reflow temperature. After the printed circuit board 1 reaches the reflow temperature, the door 13 opens, and the printed circuit board 1 is carried out and cooled. Thus, the temperature profile shown in FIG. 5 can be obtained. The heaters 7 and 8 are returned to their original positions by the motors 9 and 10, respectively.

In the present embodiment, a heater is used as the heating means, but a hot air blower having a heating effect equivalent to that of the heater may be used as the heating means. 2A and 2B show a heating device using both a heater and a hot air blower, wherein FIG. 2A is a side view and FIG. 2B is a top view of the heater. A hot air blower (not shown) is provided above the heater 16, and hot air passes through a hole formed substantially perpendicularly to the heater 16 so that the fan 1
It is blown at 7. When the heater 16 alone is used, when a difference occurs in the temperature absorption due to a difference in the color of the printed circuit board 1, the effect of adding the heating by the hot air is more effective in making the temperature of the printed circuit board uniform.

FIG. 3 is a system diagram in which a plurality of the present reflow apparatuses are connected. Reference numeral 15 denotes a stocker for stocking the printed circuit board 1. Printed circuit board 1 from stocker 15
Can be conveyed to each reflow device by the conveyor 2, and the doors 13 can be closed in a state where the sheets are carried one by one to start reflow all at once. Since the processing is performed all at once, it is easy to control, and it is possible to control a plurality of reflow devices at once. When the reflow is completed, the conveyor 2 is rotated and the printed circuit board 1 is carried out. If the number of connected reflow devices is determined based on the production volume, useless space is not occupied, and if it is necessary to increase the production volume, the response can be appropriately made by increasing the number of connected reflow devices. It is possible.

[0018]

As described above, according to the present invention, by changing the distance between the heater and the printed circuit board, the temperature of the printed circuit board can be controlled to an optimum temperature for reflow. Even when the tact is large, the printed circuit board can be heated to a required temperature without increasing the overall length of the reflow device.

Further, in the case of heating only by a heater, when a difference occurs in temperature absorption due to a difference in color of the printed circuit board, the temperature of the printed circuit board can be made uniform by adding heating by hot air. In addition, the heating unit raises the temperature at a position away from the printed circuit board, and approaches the printed circuit board after reaching the preheating temperature, preventing the occurrence of electronic component failure due to rapid heating and the conventional method. Even when the production tact is large as in the case of the apparatus, the printed board can be heated to a required temperature without increasing the overall length of the reflow apparatus.

Further, since the printed circuit board is heated while stopped in the reflow device, it is possible to easily cope with a change in temperature setting and production tact. In addition, since the reflow device is shut off from outside air by the door during heating, the temperature can be raised efficiently. Furthermore, by connecting a plurality of the reflow devices in series and providing a reflow system having a stocker on the loading side capable of stocking more printed circuit boards than the number of reflow devices, the number of connected reflow devices can be determined according to the production amount. Therefore, it is possible to easily respond to changes in production volume and production tact without occupying wasted space.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory diagram in one embodiment of the present invention.

FIG. 2 is a schematic explanatory view of a heater in one embodiment of the present invention.

FIG. 3 is a schematic explanatory diagram of a system according to an embodiment of the present invention.

FIG. 4 is a schematic explanatory view of a conventional reflow device.

FIG. 5 is a reflow temperature profile.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed circuit board 2 Conveyor 4a Heater 4b Heater 4c Heater 5a Heater 5b Heater 5c Heater 7 Upper surface heater 8 Lower surface heater 9 Motor and drive part 10 Motor and drive part 13 Door 14 Actuator 15 Stocker 16 Heater (hole)

Claims (6)

[Claims] 1. A reflow apparatus in a mounting process of an electronic component for connecting a pattern electrode of a printed circuit board and an electrode of an electronic component by heating and melting cream solder, wherein a heating unit for heating the printed circuit board is mounted on the printed circuit board. A reflow device characterized by being vertically movable. 2. The reflow apparatus according to claim 1, wherein a heater or a hot air blower is used for the heating unit. 3. A heating unit, wherein a heater and a hot air blower are used in combination, the hot air blower is provided above the heater, and hot air is blown through a hole formed substantially perpendicular to the heater. 2. The reflow apparatus according to 1. 4. The reflow apparatus according to claim 1, wherein the heating section is provided so as to approach the printed circuit board after the temperature rises from a position distant from the printed circuit board and reaches a preheating temperature. 5. A reflow device comprising: a conveyor that drives a printed circuit board to be stopped after being loaded into a substantially central portion of the reflow device, and is driven to carry out the printed circuit board after heating; The reflow apparatus according to claim 1, further comprising a door that seals the outlet. 6. The reflow device is connected in series with a plurality of reflow devices, and a stocker capable of stocking more printed circuit boards than the number of the reflow devices is provided on the loading side, and the printed circuit boards are sorted and transported one by one to the reflow device. A reflow system in which reflow start, stop, and carry-out are performed simultaneously.