JPH10209633A - Printed wiring board receiving stand and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make excellent solder printing possible, preventing a printed wiring board from bending by printing pressure, by fixing with resin, a surface on which electronic parts are mounted of the printed wiring board, and/or a plurality of supporting pins coming into contact with the electronic parts. SOLUTION: A holding board 12 to which supporting pins 22 are temporarily fixed is set in a mold by turning it upside down, and fixing resin 130 is infected from the resin filling hole 31 provided in the holding board 12 and is hardened. And a printed wiring board receiving stand 10 having supporting pins 22 adjusted and fixed to the heights of electronic parts and the surface of a printed wiring board on which the electronic parts have been mounted, is fixed to the receiving stand fitting part 20 of a printing machine, and solder printing to the second surface 3 of the printed wiring board 1 is performed, causing them to support the electronic parts mounted surface 2 of the printed wiring board 1 or/and the surfaces of the electronic parts 5. Accordingly, it becomes possible to perform solder printing free from defects, almost without bending the printed wiring board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board having electronic components mounted on both sides, and in performing solder printing on the second surface of the printed wiring board, the first surface of the printed wiring board is reliably formed. The present invention relates to a printed wiring board support that can be supported on a board and a method for manufacturing the same.

[0002]

2. Description of the Related Art Recently, so-called double-sided mounting, in which electronic components are mounted on both sides of a printed wiring board, has been widely performed in order to reduce the size and weight of electronic circuits. In this double-sided mounting, first, electronic components are mounted on a first surface of a printed wiring board, and then electronic components are mounted on a second surface.

In order to mount electronic components on the second surface of the printed wiring board, the printed wiring board having the electronic components mounted on the first surface is turned over, and after solder printing is performed on the second surface. Mount and fix electronic components. To actually mount and fix the electronic components, a receiving table or a jig for supporting the back surface of the printed wiring board, that is, the second surface, is used in the solder printing machine or the mounting machine.

The following is known as a method for supporting the second surface of a printed wiring board, that is, the back surface. FIG.
The figure shows a pin-supported printed wiring board receiving stand, in which a large number of support pins 22 are erected in a matrix on a jig body 21 on the board. These support pins 22
Is erected at a position avoiding the position of the electronic component 5 mounted on the first surface of the printed wiring board 1.
Support the substrate.

FIG. 8 shows a cut-out type printed wiring board receiving stand. The receiving stand 10 is formed of a block made of metal or resin such as aluminum or methacrylic resin. On the upper surfaces of these blocks, concave portions 9 are formed by milling or the like at corresponding positions of the mounted electronic components, and the electronic components 5 mounted on the first surface of the printed wiring board and projecting from the concave portions 9 are formed. And supports the substrate of the printed wiring board 1.

However, due to the demand for smaller and lighter electronic circuits, the thickness of printed wiring boards has become increasingly thinner, and the mounting density of electronic components has been increasing. The above-mentioned conventional printed wiring board supporting method has the following problems.

That is, in the pin supporting method, it is necessary to support the printed wiring board with a large number of support pins 22 as the substrate of the printed wiring board becomes thinner. In addition, in the high-density mounting board, the area where the electronic components are mounted is often localized, and the area where the electronic parts are not mounted is small and mainly linear, so the thin support pins are thin. Since only the printed wiring board can be installed, the printed wiring board may be locally bent by the printing pressure at the time of solder printing. If the printed wiring board is bent during solder printing, a defect occurs on the solder printing surface.

The printed wiring board receiving table of the cut-out type is obtained by cutting a concave portion 9 corresponding to an electronic component on an aluminum plate or an acrylic resin plate by milling or the like. As shown in (1), it is inevitable to cut out by combining a plurality of mounted electronic components adjacent to each other, and since the number of cut-out portions increases, the processing cost becomes expensive and is not practical. Further, it is conceivable that the area of the concave portion becomes large, the supporting area of the substrate becomes small, and sufficient support cannot be obtained.

[0009] FIG.
In the printed wiring board support disclosed in Japanese Patent Publication No. 900, a holding plate 11 having slidable pins in lattice-shaped holes is positioned above a first surface on which electronic components are mounted. After the unevenness of the printed wiring board is adjusted by its own weight, the viscous fluid in the space 12 of the holding plate 11 and the solidification thereof are used to support the printed wiring board using a holding jig having pins fixed thereto. . This is intended to evenly support the printed wiring board with support pins having a height corresponding to the unevenness of the mounted electronic component, but the details are unknown from this publication.

However, many of recent printed wiring boards are equipped with electronic components (indicated by reference numeral 5-1) that cannot withstand the printing pressure load. Otherwise, the electronic component may be damaged. In addition,
6 to 9, reference numeral 6 denotes a solder cream, 7 denotes a printing plate, and 8 denotes a squeegee.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of solder printing for mounting electronic components on the rear surface of a printed wiring board, which prevents the printed wiring board from being bent by a printing pressure and provides good solder printing. And a method of manufacturing the same.

[0012]

In order to achieve the above object, the present inventors have invented a printed wiring board pedestal capable of performing defect-free solder printing and a method of manufacturing the same.

According to the present invention, there is provided a printed wiring board receiving stand characterized in that a surface of a printed wiring board on which electronic components are mounted and / or a plurality of support pins abutting on the electronic components are fixed with resin. .

Further, according to the present invention, a holding plate having a plurality of support pin through holes is installed in parallel with the electronic component mounting surface of the printed wiring board, and the plurality of support pins are inserted into the support pin through holes. Wherein the support pins are temporarily fixed to a holding plate while the support pins are in contact with the electronic component mounting surface, and then the support pins are fixed with resin. In the way.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 6 shows a printed wiring board receiving base 10 of the present invention, in which a plurality of support pins 2 are provided.
2. The height of the printed wiring board 2 is in contact with the printed wiring board surface 2 and / or the mounted electronic component 5 surface, and where the printed wiring board and the mounted electronic component are located, the entire printed wiring board 1 is supported on the upper surface of the mounted electronic component. It is characterized by.

In the present invention, as shown in FIGS. 2A and 2B, the plurality of support pins 22 provided on the pedestal 10 are provided in a matrix square or diamond shape over the entire surface of the printed wiring board. The holding plate 12 is provided with a large number of through holes 23. The shape of the support pin 22 may be either a prism or a cylinder, but a columnar pin is convenient for manufacturing, and the diameter of the cylinder or the length of one side of the prism is 1 to 3.
It is preferably 5 mm. In particular, in the case of a thin high-density mounting printed wiring board having a thickness of about 0.6 mm, in order to prevent the printed wiring board from being bent by the printing pressure, it is necessary to set the support pins at 1 cm intervals. A range of a side length of 2-3 mm is appropriate.

In order to reduce the printing pressure load on the electronic component, the diameter of the support pin or the length of one side should be 3 to 5 m.
m is preferable. Further, the length of the support pin varies depending on the height of the electronic component, but is preferably in the range of 15 mm to 30 mm. As described later, the support pin used to manufacture the cradle of the present invention is used. Must be equal in length.

The holding plate 12 holds a plurality of support pins 22 when the support pins 22 are erected over the entire surface of the printed wiring board. The through holes 23 for erected the support pins 22 are formed in a matrix. A metal plate made of stainless steel or aluminum, a fiber reinforced composite material sheet, or a plastic plate made of methacrylic resin or the like is used. As shown in the figure, when the electronic component 5-1 which does not want to apply the printing pressure is mounted, the position of the component can be visually checked by using the transparent holding plate, and the third embodiment described later is used. As shown in (1), only the corresponding support pins can be selected and dropped. The diameter or the length of one side of the through hole 23 is set to a size that allows the support pin 22 to move up and down smoothly.

The method of manufacturing the pedestal according to the present invention will be described with reference to FIGS. As shown in FIG. 2, the electronic component mounting surface 2 of the printed wiring board 1 is mounted on the stage 4-1 of the jig 4.
Is set as an upper surface, set by a frame 4-3 that slides along a groove (not shown) of the fixed frame 4-2, and fixed with a fixing screw 4-4. Next, the support pin 22 is inserted into the through hole 23.
Are placed one on top of another and placed in parallel with the electronic component mounting surface 2. Next, the height of the support pins 22 is adjusted so that the support pins 22 contact the lower surface of the printed wiring board surface 2 or the electronic component 5 surface.

Next, as shown in FIG.
The support pins 22 are temporarily fixed to the holding plate 12 by casting.
As the resin 14 for temporary fixing, an adhesive having a low adhesive strength is used.

As shown in FIG. 4, the holding plate 12 on which the support pins 22 are temporarily fixed is turned upside down, set on a mold frame 30, and fixed through a resin injection port 31 provided on the holding plate 12. After the resin 13 is injected, the fixing resin 13 is cured. Next, the mold 30 is removed, and the cradle 1 shown in FIG.
0 is produced.

As the fixing resin 13, a room temperature curing type unsaturated polyester resin, polyurethane resin, silicone rubber or the like is preferably used. As shown in the embodiment, in order to fix and hold the support pin 22 only with the fixing resin 13, use a fixing resin having a hardness of 40 to 90 after curing in order to suppress the downward movement of the support pin. Is preferred. If a resin having low adhesiveness to the support pins is used as the fixing resin, unnecessary support pins 22 can be extracted after curing.

In the pedestal of the present invention, the temporary fixing of the support pins 22 to the holding plate 12 is not firmly fixed, so that the support pins 22 are fixed and held only by the fixing resin.

When solder printing is performed on the second surface of the printed wiring board using the pedestal of the present invention, only the support pins to which printing pressure is directly applied linearly through the printed wiring board are fixed and held. Although it depends on the hardness of the rubber-like resin, the moment it is slightly pressed down with reference to the holding plate 12, many other support pins to which printing pressure is not directly applied do not move in the vertical direction. It remains held in place. The load is transferred to the support pin 22 to which the printing pressure is directly applied as the squeegee moves, but the printing pressure itself is supported by the entire support pin in such a state. Therefore, even if there is a support pin to which the printing pressure is directly applied, that is, even if there is an electronic component facing the support pin, the applied printing pressure is reduced, and the electronic component is not damaged.

As described above, the pedestal according to the present invention has a printed wiring board surface 2 on which electronic components are mounted as shown in FIG.
And support pins 22 fixed and adjusted to the height of electronic components
The printed circuit board receiving stand 10 having the above structure is fixed to the receiving stand mounting part 20 of the printing machine, and the electronic component mounting surface 2 and / or the electronic component 5 surface of the printed circuit board 1 is supported. Since solder printing is performed on the second surface 3, the printed wiring board hardly bends, and defect-free solder printing can be performed.

[0026]

The present invention will be described in more detail with reference to the following examples. The support pin 22 used in this example has a diameter of 2.
A 9 mm rod made of ABS resin was used. Length is 15
mm and 20 mm were prepared. Also, the holding plate 12
Is a commercially available methacrylic resin plate having a thickness of 5 mm (trade name: "Acrylite" manufactured by Mitsubishi Rayon Co., Ltd.), using a NC router (manufactured by Exelon Automation) to penetrate a support pin having a diameter of 3 mm into a matrix-shaped square. Hole 23 was drilled and used. The through hole interval was 1 cm.

The fixing resin 13 used is as follows. Silicone prepolymer KE1300T blended with curing agent Cat-1300 (manufactured by Shin-Etsu Chemical Co., Ltd.) Coronate 402 blended with crosslinker tyramine ML100
8 (manufactured by Nippon Polyurethane Industry Co., Ltd.) As the temporary fixing resin 14, a poval adhesive (manufactured by Yamato Co., Ltd.) was used.

[Embodiment 1] As shown in FIG.
A component mounting surface 2 of a 0.6 mm-thick printed wiring board 1 on which an electronic component 5 is mounted on one side is set on a stage 4-1 of a jig 4 made of a resin, and a slide frame 4-3 is mounted on the printed wiring board. And slide it to the edge of
-4 was squeezed and fixed. In FIG. 1, arrows indicate the moving direction of the slide frame 4-3.

Next, the fixed frame 4-2 and the slide frame 4
-3 was placed in parallel with the component mounting surface of the printed wiring board by stacking the holding plate 12 having through holes 23 formed in a matrix square, and the support pins 22 were inserted through the holes 23. The support pin 22 falls by its own weight, and is
After the sponge sheet is overlaid on the upper surface of the holding plate 12 and lightly pressed to bring the support pins 22 into contact with the printed wiring board surface 2 and the electronic component 5 surface, the temporary fixing resin 14 is formed. The support pins 22 were temporarily fixed to the holding plate 12 using a poval adhesive (manufactured by Yamato Corporation). Since the height of the highest mounted electronic component 5 of the printed wiring board used in this example was 5 mm, a support pin having a rod length of 15 mm was used as the support pin 22.

Next, the holding plate 12 to which the support pins 22 are temporarily fixed is turned upside down and set on a SUS frame 30 as shown in FIG. As the resin 13, a silicone prepolymer KE1300T (manufactured by Shin-Etsu Chemical Co., Ltd.) containing a curing agent Cat-1300 was injected, and left at room temperature for 24 hours to cure. After the resin 13 was cured, the mold 30 was removed, and the cradle 10 was formed as shown in FIG.

In the obtained cradle 10, the support pins 22 of the holding plate 12 are temporarily fixed because the support pins 22 are peeled off from the holding plate 12 even with a small force. Will be supported. The hardness of the fixing resin used in this example was 40.

Example 2 Since the height of the highest mounted electronic component 5 of the printed wiring board 1 used in this example was 7 mm, the same procedure was carried out except that a support pin 22 having a rod length of 20 mm was used. In the same manner as in Example 1, a printed wiring board receiving stand 10 was prepared.

[Embodiment 3] In FIGS. 2A and 2B,
There is an electronic component 5-1 for which it is not desired to apply a printing pressure during solder cream printing. Since it was visually observed through the holding plate 12 that the support pin 22 abuts on the electronic component, only the through hole 23 corresponding to the upper portion is supported. Pin (reference number 22-
Except that 1) was not inserted, in the same manner as in Example 1,
A printed wiring board receiving stand 10 was prepared.

[Embodiment 4] In FIG.
A printed wiring board receiving stand 10 was prepared in the same manner as in Example 1 except that Coronate 4028 (manufactured by Nippon Polyurethane Industry Co., Ltd.) in which the crosslinking agent Tyramine ML100 was blended was used as No. 3. The hardness of the fixing resin 13 used in this example was 85, which was higher than that of Example 1, so that the vertical movement of the support pin 22 with respect to the pressure load was small.

[Use Example] As shown in FIG. 6, a printed wiring board having electronic components mounted on the first surface is set on the printed wiring board receiving table 10 prepared in the first to fourth embodiments, and is screen printed. When solder printing was performed on the second surface of the printed wiring board while being fixed to the cradle mounting portion 20 of the machine, no defect such as falling off or bleeding of the solder occurred, and a good solder printed surface was obtained. . Further, in the cradle obtained in Example 3, no printing defect was recognized despite the absence of the support pin (reference numeral 22-1). This is because the printing pressure was supported by the eight support pins 22-2 around the reference numeral 22-1, and, as a matter of course, the mounted component 5-1 was not damaged at all.

Further, when the set of the printed wiring board and the pedestal of the present invention was used for an electronic component mounting apparatus to mount components on the second surface of the wiring board, there was no bending of the printed wiring board. Position accuracy was secured, and good component mounting results were obtained.

[0037]

According to the printed wiring board receiving stand of the present invention, the printed wiring board and / or the electronic component surface can be stably supported by a plurality of support pins abutting on the electronic component mounted printed wiring board surface or the electronic component surface. Features. For this reason, when the electronic component-mounted printed wiring board is set on the pedestal of the present invention and fixed to a jig of a screen printing machine to perform solder printing, defects such as falling off or seepage of the solder do not occur at all, Good printing surface is obtained. In addition, when mounting a component on the second surface of the wiring board using the set of the printed wiring board and the pedestal of the present invention in an electronic component mounting device, the printed wiring board does not bend, so that positional accuracy is secured. And good component mounting results can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing a state where a printed wiring board is set on a jig.

FIG. 2A is a plan view showing a state in which the height of pins is adjusted after setting a printed wiring board on a jig, and FIG.
3 is a sectional view taken along line XX of FIG.

FIG. 3 is a cross-sectional view showing a state in which a support pin whose height has been adjusted is temporarily fixed to a holding plate.

FIG. 4 is a cross-sectional view showing a state in which a support pin temporarily fixed to a holding plate is fixed with a resin.

FIG. 5 is a sectional view of a pin-supporting type printed wiring board receiving base of the present invention.

FIG. 6 is an explanatory diagram showing a state in which the printed wiring board is supported by the receiving stand of the present invention.

FIG. 7 is an explanatory view showing a state in which a printed wiring board is supported by a conventional pin method.

FIG. 8 is an explanatory view showing a state in which a printed wiring board is supported by a conventional cut-out type pedestal.

FIG. 9 is an explanatory diagram showing a state in which the printed wiring board is supported by a support pin fixing jig which is made uneven to the circuit board.

[Explanation of symbols]

 Reference Signs List 1 printed wiring board 2 first surface on which electronic components are mounted 3 second surface of printed wiring board 4 jig 4-1 stage 4-2 fixed frame 4-3 slide frame 4-4 screw for fixing slide frame Reference Signs List 5 electronic component 5-1 electronic component that cannot withstand pressure load 6 solder cream 7 printing plate 8 squeegee 9 electronic component receiving recess 10 printed wiring board receiving stand 11 support pin holding plate 12 holding plate 13 fixing resin 14 temporary fixing resin 20 Cradle mounting part 21 Support pin fixing jig 22 Support pin 22-1 Where there is no support pin 22-2 Support pin surrounding 22-1 23 Through hole 30 Formwork 31 Inlet

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshihiro Taniguchi 87-5, Kojirobukuro, Kawagoe-shi, Saitama Pref. (72) Inventor Sawako Sato Kawagoe-shi, Saitama 87-five, Oirobukuro 5

Claims (3)

[Claims] 1. A printed wiring board receiving base, wherein a plurality of support pins which are in contact with the electronic component mounted surface and / or the electronic component of the printed wiring board are fixed with resin. 2. A holding plate having a plurality of support pin through holes is installed in parallel with the electronic component mounting surface of the printed wiring board, and a plurality of support pins are inserted through the support pin through holes. 2. The printed wiring board receiving stand according to claim 1, wherein the support pins are temporarily fixed to the holding plate while the support pins are in contact with the electronic component mounting surface, and then the support pins are fixed with resin. Method. 3. The method according to claim 2, wherein the resin fixing the support pins is a cured rubber-like resin.