JP2877019B2 - Mold structure of printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die structure for a printed wiring board in which no crack occurs in a solder resist when a double-sided or multilayer printed board is punched.

[0002]

2. Description of the Related Art FIG. 3 is a cross-sectional view of a main portion of a conventional printed wiring board mold structure in a press-punched state. The printed wiring board 100 is composed of a base material 103 on both sides of which a conductor 101 is masked with a solder resist 102. The base material 103 is held by a shetter 104 and a male mold 105, and is sheared using a female mold (blade) 106. Part 107
Is punched along.

[0003] In the drawing, reference numeral 108 denotes a stripper for removing the base 103 biting the female mold 106 when the base 103 is punched, and 109 denotes a solder resist 1.
This is a printing unit that indicates a component name and a position provided on the device 02.

[0004]

By the way, at the time of this conventional punching of a base material, the base material end (shear portion 108)
The smaller the distance between the conductor and the conductor 101, the more the printed wiring board 1
The larger the thickness of 00 was, the more cracks occurred.

[0005]

The inventors of the present invention examined this phenomenon in detail, and found that
Near the shetter 104 and solder resist 102
Between the male mold 105 and the solder resist 102
1 and s2, the base material 10 is punched (sheared).
3 cannot completely hold the flexible base material 103 between the gaps s1 and s2, and solder resist cracks 110 and 111 are generated at the positions shown in the drawing. In order to solve the above-described problem, it was found that the above-mentioned problem was particularly remarkable because the wire 102 was pulled in the direction of the arrow a. Reached.

[0006] Specifically, when punching, the shetter and the male mold have, at the time of punching, a portion opposed to a portion having a width of 0.3 to 0.6 mm along the outer shape of the printed wiring board and the shear portion of the slit. The portion other than the edge portion is a depth obtained by subtracting the thickness of the solder resist facing the edge portion from the thickness of the conductor constituting the printed wiring board, the solder resist on the conductor, and the printed portion indicating the component name and position. Thus, uniform engraving is performed. This engraving is preferably performed by a metal etching method.

[0007]

According to the die structure of the printed wiring board according to the present invention, when the printed wiring board is punched, the male mold and the shetter are not engraved in the solder resist by 0.3 to 0.6.
The edge part having a width of mm is abutted and held firmly by this edge part. In addition, the engraving of the male mold and the shetter is uniformly processed with high precision by metal etching.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a main part showing a press-punched state of a mold structure of a printed wiring board according to the present invention, and FIG. 2 is an end view of the shetter seen from the direction of arrows AA in FIG.

The mold 1 includes a shetter 2 and a male mold 3.
A printed wiring board made of a base material 6 having conductors 4... Masked with a solder resist 5 on both surfaces thereof is held by the shetter 2 and the male mold 3.

In the hold state, the edge 8a and the edge 9a of the shetter 2 and the male mold 3 are in contact with the solder resist 5 at a portion along the shearing portion 7 of the base material 6, and the edge 8a and the edge 9a width w1
Is 0.3 m from the sheared part 7 from which the outer shape is punched
m is about 0.6 mm.

The widths of the edge portions 8a and 9a were determined by experiments as follows. The minimum hold width (the width of the edge portion 8a and the edge portion 9a) is 0.3 m
If it is less than m, the contact width is too narrow, so that the solder resist 5 cannot be held sufficiently and acts as a cutting blade. . In view of this point, the minimum width of the edge portions 8a and 9a is set to 0.3 mm.

If the maximum hold width (the width of the edge portions 8a and 9a) is widened, especially if it exceeds 3.0 mm, the solder resist 5 of the edge portions 8a and 9a will be removed.
Is weakened, and solder resist cracks occur as in the prior art. Therefore, in the current design specifications, most models are designed with a distance from the outer end face to the conductor of about 0.6 mm in order to secure an effective wiring area. Therefore, the maximum width of the edge portions 8a and 9a is large. Was set to 0.6 mm.

The widths w2 of the edge portions 8b and 8c and the edge portions 9b and 9c that are in contact with the solder resist 5 are also 0.35 to 0.45 mm from the sheared portions 7 where the slits are punched in the same manner as described above. It was decided.

The edge portions 8a to 8c and the edge portion 9
The portions 10 other than a to 9c are engraved by etching. In this embodiment, the conductor 4 disposed on the base material 6, the solder resist 5 on the conductor 4, and a printing unit (ink) Formed) 11
From the thickness t1 generated by the solder resist 5 at the portions facing the edge portions 8a to 8c and the edge portions 9a to 9c.
Depth t1-t2 obtained by subtracting the thickness t2 is 0.06 to
Since it is 0.07 mm, the engraving depth is 0.06
〜0.07 mm.

The engraved depth is determined by the conductor 4, the solder resist 5 on the conductor 4, the printed portion 9 indicating the part name and position, and the edge portions 8 a to 8 c and the edge portion 9.
It is increased or decreased by a change in the thickness or the like of the solder resist 5 at a portion opposed to a to 9c, and it is needless to say that the value is not limited to the above range.

If the engraving depth is not appropriate, the following problems occur, so that the engraving depth is a very important requirement when punching. That is,
If the engraving depth is too deep, shatter 2 and male 3
When the printed wiring board is held by the above, the shetters 2 and the male molds 3 have the edge portions 8a to 8c and the edge portions 9a to 9c.
Only the solder portion 5 contacts the solder resist 5 in the vicinity of the shear portion 7, so that a large holding force (about 50 tons) is applied to the shear portion 7.
It concentrates on the solder resist 5 in the vicinity and destroys the base material 6 on which the solder resist 5 is arranged, and further, the solder resist 5 bites into the shetter 2 so that the base material cannot be spattered.

When the engraving depth is shallow, when the printed wiring board is held by the shetter 2 and the male mold 3,
When the holding force due to the edge portions 8a to 8c and the edge portions 9a to 9c is insufficient, when the printed wiring board is punched using the female die (blade) 12, cracks are easily generated in the solder resist 5 for the same reason as in the related art. turn into. In FIG. 2, the shetter 2 facing the base material 6 is illustrated, but the male mold 3 has substantially the same configuration as this and is not illustrated.

The engraving of the above-mentioned shetter 2 and the male mold 3 can be carried out by the electric discharge machining used in the production of the mold, but there is a large variation in machining (engraving depth accuracy: ± 0.1 mm or more, engraving). Position accuracy: ±
0.2 mm), and the cost required for processing is considerably high. Therefore, an alternative to this processing method has been desired. In view of this point, the present inventors have implemented a processing method using metal etching (corrosion technology) having the following advantages.

That is, according to the etching process, the engraving depth accuracy is ± 0.01 mm or less, the engraving position accuracy is ± 0.1 mm, and the cost including the mask can be reduced.

The film for metal etching is prepared by a laser plotter using a negative film below the film surface as a film for a male mold and a negative film above the film surface as a film for a shetter. Since the etching process is conventionally known, a description thereof will be omitted.

The punching by the mold 1 having the above configuration is performed as follows. That is, from the state where the base material 6 is completely held by the shetter 2 and the male mold 3 as shown in FIG. 1, the female mold (blade) 12 is lowered and the printed wiring board (base material 6) is punched. In FIG. 1, illustration of a female die (blade portion) and a stripper used for punching a slit is omitted.

The female die (blade) 12 collides with the stripper 13 urged upward by a spring (not shown), pushes it down, and returns to the original position after stopping. At this time, the base material 6 biting the female mold (knife) 12 is spattered by the elastic force of the stripper 13. In the double-sided / multi-layer printed wiring board thus punched, no crack is generated in the solder resist.

[0023]

As described above, the die structure of the printed wiring board according to the first aspect of the present invention is such that the shatter and the male die are formed along the outer shape of the printed wiring board and the slit along the shear portion of the slit at the time of punching. A portion facing the portion having a width of 3 to 0.6 mm is defined as an edge portion, and a portion other than the edge portion is a conductor constituting the printed wiring board, a solder resist on the conductor, and a printing portion indicating a part name and position. Since the uniform engraving is performed at a depth obtained by subtracting the thickness of the solder resist facing the edge portion from the thickness generated by the edge portion, the vicinity of the sheared portion of the base material (printed wiring board) is not engraved. It is held at the edge of 0.6 mm, and the substrate is firmly held by the male mold and the shetter.

Therefore, at the time of press punching, the printed wiring board is not bent, and the solder resist is not pulled in the direction of the shearing portion, so that no crack is generated. Furthermore, since no crack is generated, the conductor can be completely protected by the solder resist, the conductor is not eroded by chemicals in rust prevention treatment, reflow, substrate cleaning, and the like, and insulation failure due to the crack can be prevented.

In the mold structure for a printed wiring board according to the second aspect of the present invention, the engraving is performed by a metal etching method. It is short and the processing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing a press-punched state of a mold structure of a printed wiring board according to the present invention.

FIG. 2 is an end view of the shetter viewed from the direction of arrows AA in FIG. 1;

FIG. 3 is a cross-sectional view of a main part showing a press-punched state of a mold structure of a conventional printed wiring board.

[Explanation of symbols]

1 ... mold, 2 ... shutter, 3 ... male, 4 ... conductor, 5 ...
Solder resist, 6: base material, 7: shearing portion, 8a to 8c,
9a to 9c: edge portion, 10: portion other than edge portion, 1
1 ... printing unit, 12 ... female type, 13 ... stripper.

Claims (2)

(57) [Claims] 1. A mold structure for a printed wiring board for punching an outer shape and a slit of a printed wiring board, comprising a shetter and a male die. The part opposite to the part having a width of 0.3 to 0.6 mm along the outer shape and the shear part of the slit is an edge part, and the part other than the edge part is
The conductor constituting the printed wiring board, the solder resist on this conductor and the uniform engraving process at a depth obtained by subtracting the thickness of the solder resist facing the edge portion from the thickness generated by the printed portion indicating the part name and position. A mold structure for a printed wiring board, wherein the mold structure is performed. 2. The die structure for a printed wiring board according to claim 1, wherein said engraving is performed by a metal etching method.