JPH0210900A - Holding method for circuit board - Google Patents

Abstract

PURPOSE:To effectively hold a circuit board rapidly at the time of switching its type by heating a real circuit board from its surface, holding it by a predetermined pressing force with a thermally flexible material from its rear face for a predetermined period of time, forming in advance a holding jig of the shape corresponding to the uneven parts of the rear face, and using it in a mounting step of a leadless electronic component. CONSTITUTION:A circuit board 4 in which the mounting of its rear face is already completed is heated from its front face by a far infrared ray heat source 5, the board 4 is energized by means provided separately with a housing 7 filled with styrene foam 6 from below, melted by the heat of the board 4, and the surface of the styrol 6 is molded. The shape of a holding jig 8 of the board formed according to this method is similar to the uneven part of the component. Further, the jig 8 is mounted in a leadless electronic component mounting machine to become a jig for effectively holding the whole rear face of the board 4 at the time of mounting of the component. Thus, the board can be effectively held rapidly at the time of switching its type, the mounting accuracy of the component is obtained, and the yield of manufacturing the board is largely improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to circuit board assembly, such as the process of mounting electronic components onto circuits that are becoming increasingly finer and finer patterned, for example in leadless electronic component mounting processes. The present invention relates to a method for holding a circuit board used in general processes.

2. Description of the Related Art Conventionally, when a lead-len type microelectronic component is mounted on an electronic circuit board, the circuit board is selectively pinned to a support plate 2 having holes 1 in a grid pattern, as shown in FIG. 3 was inserted and the back side of the circuit board 4 was partially held in an automatic machine.

However, in recent years, the mounting density of circuit boards has been increasing, and the number of cases in which both sides are mounted is increasing.Furthermore, the boards themselves are becoming thinner, and structures with splits, etc. are becoming common. In the process of mounting the second side of such a circuit board, even if you try to hold the circuit board using the method described above, there is a limit to the selection of the insertion position of pin 3, and more delicate alignment etc. This required complicated work when changing production models.

For reasons beyond the problems to be solved by the invention, if the circuit board is not held sufficiently, the mounting accuracy of electronic components is impaired, which is a major factor in deteriorating the yield in manufacturing circuit boards.

In view of the above problems, the present invention provides a means for quickly and reliably holding a circuit board when changing models.

Means for Solving the Problems In order to solve the above-mentioned problems, the circuit board holding method of the present invention is designed to hold the entire back surface of the circuit board, which has uneven parts already mounted on the back surface, by holding the actual circuit board. A holding jig with a shape that corresponds to the unevenness of the back surface is created in advance by heating it from the front side and holding it with a heat-softening material from the back side with a predetermined pressing force for a certain period of time. This method is used in the mounting process, etc.

Function: By employing the method described above, the present invention makes it possible to easily obtain a jig for holding the entire circuit board at all times, and it is also possible to minimize variations in yield from lot to lot.

EXAMPLE Hereinafter, a method for making a holding jig for a circuit board according to a first example of the present invention will be described with reference to FIG.

The circuit board 4, which has already been mounted on the back side, is heated from the front side with a far-infrared heat source 5, and the styrofoam is heated from below.
The housing 7 filled with f is biased against the upper circuit board 4 by means provided separately, and is melted by the heat of the circuit board 4.
Molding the surface of Styrofoam/V6.

As shown in FIG. 3, the shape of the circuit board holding jig 8 produced by the above method corresponds to the unevenness of the component. Furthermore, the holding jig 8 is attached to a leadless electronic component mounting machine as shown in FIG. 4, and becomes a jig that can reliably hold the entire back surface of the circuit board 4 when leadless electronic components are mounted.

In this embodiment, the molding material may be styrofoam, or any other material that softens and melts at a relatively low temperature. Also, the heat source may be any one that can heat the circuit board to an appropriate temperature.

It goes without saying that even if a heat-softening material is not used, a viscous fluid or the like that dries and solidifies may be used, depending on the properties of the circuit board to be molded.

FIG. 4 shows a method for making a circuit board holding jig according to a second embodiment of the present invention. A holding plate 11 having slidable pins 10 in grid-like holes was placed above the circuit board 4 which had irregularities in the experimental method, and the unevenness of the circuit board 4 was caused by the weight of the pins 10. let In this state, the pin 10 is fixed in the space 12 of the holding plate 11 with a viscous fluid that can be fixed by solidification, and used as the holding jig.

Effects of the Invention U As described above, the method for holding a circuit board of the present invention heats the actual circuit board from the front surface and heats the back surface in order to hold the entire back surface of the circuit board, which has unevenness due to components already mounted on the back surface. A holding jig with a shape that corresponds to the unevenness of the back surface is created in advance by holding it with a heat-softening material for a certain period of time and with a predetermined pressing force, and is used in the mounting process of leadless electronic components, etc. As a result, the circuit board can be held quickly and reliably when changing models, and the accuracy of mounting electronic components can be ensured.
The yield rate for manufacturing circuit boards will be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a method for making a circuit board holding jig in a first embodiment of the present invention, FIG. 2 is a perspective view showing a circuit board holding jig in the same embodiment, and FIG. A perspective view showing the process of surface mounting using the same holding jig, No. 4
The figure is a cross-sectional view showing the process of creating a circuit board holding jig in a second embodiment of the present invention, and FIG. 6 is a perspective view showing a conventional board holding method. 4... Circuit board, 6... Heat source, 6.
...Thermosoftening material, 7...Holding jig. Name of agent: Patent attorney Toshio Nakao and one other person

Claims (2)

[Claims] (1) By heating the actual circuit board from the front side and holding it with a heat-softening material from the back side with a predetermined pressing force for a certain period of time, a holding jig with a shape that corresponds to the unevenness of the back side is created in advance. , a circuit board holding method that uses this holding jig to hold the entire back side of the circuit board during an electronic component mounting process. (2) Position the holding plate with slidable pins in the grid-like holes above the actual circuit board, and after using the weight of the pins to follow the unevenness of the circuit board, attach the pins with adhesive. The method of holding a circuit board according to claim 1, which comprises fixing the circuit board and creating a circuit board holding jig.