JPH04199692A - Method of correcting warpage of circuit board - Google Patents

Abstract

PURPOSE:To enable a circuit board to be corrected in warpage and cooled down without stopping a manufacturing line by a method wherein the circuit board is corrected in warpage at a point located out of a manufacturing line. CONSTITUTION:A circuit board 2 transferred to a correcting station 10 is placed on chain conveyers 11a and 11b. The chain conveyers 11a and 11b are shifted by an air cylinder in a Y direction vertical to the moving direction of a manufacturing line 15 to enable the circuit board 2 on the conveyers 11a and 11b to be put out of the manufacturing line 15 tentatively. The board 2 is corrected to be flat and then cooled down at a position out of the manufacturing line 15 so as not to warp again. When a following circuit board 2 is placed on other chain conveyers 12a and 12b, the circuit board 2 on the chain conveyers 12a and 12b is tentatively put out of the manufacturing line 15. By this setup, as a warpage correcting operation takes place at a position out of a manufacturing line, it can be efficiently carried out using a required time without stopping the manufacturing line.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for correcting warpage of a circuit board.

[Prior Art] Conventionally, warping caused in the circuit board manufacturing process, etc., can be avoided when the circuit board 2 is placed in a heat insulating tank 1, as shown in FIG. Place them one on top of the other,
Straightening was carried out by heating and slow cooling under the temperature profile conditions shown in FIG. 6 using a heater 4 and a fan 5 placed in the heat insulating tank J with a partition plate 3 in between. Note that 6 is a fan motor, and 7 is a door of the heat insulation tank 1.

[Problems to be Solved by the Invention] However, such a method for correcting warpage of a circuit board has a problem in that the processing time is extremely long due to batch processing. In addition, this method has the problem that workers are required to take work in and out of the heat insulating tank 1 because the process is completely removed from the production line.

Furthermore, since most circuit boards with electronic components mounted on them have not been corrected for their warpage, when mounting components using image recognition, the pattern on the circuit board is difficult to detect due to the camera's depth of field. There have been problems such as the solder becoming detached and not being able to be mounted, mounting errors occurring when mounting chip components, and variations in solder thickness occurring when printing solder.

In order to solve these problems, consideration has been given to heating the circuit board on a conveyor to a temperature above the glass transition point of the circuit board, correcting the warpage, and then cooling it to room temperature. . However, in this case, it is necessary to allow a cooling time of about 1 to 2 minutes to prevent the warping from returning.
During this time, the production line must be stopped, which poses a problem in that production capacity decreases.

An object of the present invention is to provide a method for correcting warpage of a circuit board, which allows correction of warpage and cooling without stopping the production line.

[Means for Solving the Problems] To explain in detail the present invention for achieving the above object, the present invention corrects the warpage of each circuit board sequentially conveyed in a production line at a correction point, and then In the method for correcting the warpage of a circuit board to be transported to the next process, at the correction point, each of the circuit boards being transported is once removed from the flow of the production line in sequence, and at a location removed from the flow of the production line, the circuit board is warped. The circuit board is corrected, and the corrected circuit boards are sequentially returned to the flow of the manufacturing line and transported to the next process.

[Operation] Each of the circuit boards thus conveyed is first removed from the flow of the production line in order to correct the warpage, and the circuit boards whose warpage has been corrected first are returned to the flow of the production line in order. When the product is transported to the next process, the position where the correction work is performed is removed from the production line, so the correction work can be performed using the required time. Moreover, in this way, the correction work can be performed without stopping the production line.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIGS. 1 and 2, the correction area 10 is placed on the left and right chain conveyors 9a, 9b from the heating furnace 8.
Of the chain conveyors 11a, 11b, 12a, 12b of the correction location 10,
Place it on the chain conveyor ILa, 11b (see Figure 1). The chain conveyors lla, llb pick up the circuit board 2, transport it to the center, and then stop conveying it. Next, each chain conveyor lla, llb, 12a, 12b
3 (see Fig. 3) along the rail 14 in the Y direction (see Figs. 1 and 3) perpendicular to the flow direction of the production line 15. 16
, and temporarily remove the circuit boards 2 on the chain conveyors lla and llb from the flow of the production line 15. At a position out of the flow of the manufacturing line 15, the left and right upper surfaces of the circuit board 2 are held down by the board holding tools 17a and 17b (fourth
(see figure), the curved surface on the protruding side of the circuit board 2 is pushed with the straightening lifting pin 18 to straighten it flat, and then the cooling fan 19
to cool down and prevent the warping from returning.

During such straightening work, the chain conveyors 12a, 1 facing the chain conveyors 9a, 9b of the heating furnace 8
2b (see FIG. 2) receives the next circuit board 2 sent out from the heating furnace 8.

When the correction of the circuit board 2 on the chain conveyors lla, llb in the standby position is completed, and the next circuit board 2 is placed on another chain conveyor 12a, 12b, each chain conveyor lla, llb.

1.2a, 12b are mounted on the common board 13 along the rail 14, and the air cylinder 1 is placed perpendicularly to the flow direction of the production line 15 (in the Y force direction (see FIGS. 2 and 3)).
6, and the circuit boards 2 on the chain conveyors 12a and 12b are temporarily removed from the flow of the production line 15. As a result, the chain conveyors lla and llb are aligned with the chain conveyors 9a and 9b of the heating furnace 8, and the corrected circuit board 2 is returned to the production line 15. In this state, the chain conveyors lla, llb start rotating again, and the corrected circuit board 2 is placed on the next chain conveyor 20a, 20b and transported to the next process.

In the above embodiment, an example is shown in which the circuit board 2 is shifted horizontally from the manufacturing line 15, but it can also be shifted vertically.

When the speed of the manufacturing line 15 is high, it is also possible to sequentially shift the circuit boards 2 that are sent in sequence in each direction, horizontally and vertically, and perform correction at each shift position.

[Effects of the Invention] As explained above, in the method for correcting warpage of a circuit board according to the present invention, each circuit board that is sequentially conveyed is removed from the flow of the production line in order to correct the warpage, and then After the warpage has been corrected, the circuit boards are returned to the production line and transported to the next process, so the position where the correction work is performed is off the production line, so the correction work can be done in the required time. . Therefore, according to the present invention, the correction work can be performed efficiently without stopping the production line.

[Brief explanation of the drawing]

1 and 2 are plan views showing each step of an example of the implementation state in the method for correcting warpage of a circuit board according to the present invention, and FIG.
The figure is a front view of the conveyor shift mechanism used in the correction area in this example, FIG. 4 is a front view of the orthodontic device used in the correction area in this example, and FIG. FIG. 6 is a temperature profile diagram of a conventional correction device. 2... Circuit board, 8... Heating furnace, 9a, 9b...
Chain conveyor, 10...correction point, lla, ll
b. 12a, 12b... Chain conveyor, 13... Base, 14... Rail, 15... Production line, 16...
... Air cylinder, 17a, 17b... Board holding tool,
18... Lifting pin for correction, 19... Cooling fan. Figure 1 Figure 3 48Y □-Y Figure 4 Figure 6 Moon

Claims (1)

[Claims] In a method for correcting warpage of circuit boards in which the warpage of each circuit board that is sequentially transported on a manufacturing line is corrected at a correction location and then transported to the next process, the circuit boards that are transported are once manufactured at the correction location. The circuit boards are sequentially removed from the flow of the production line, the warpage of the circuit boards is corrected at a location removed from the flow of the production line, and the corrected circuit boards are sequentially returned to the flow of the production line and transported to the next process. A method for correcting warpage of a circuit board, characterized by: