JPH05283820A - Printed-circuit board - Google Patents

Abstract

PURPOSE:To realize compactness of a board, reducing the projecting portion of a protruded part from a board remaining after cutting, by making the slit ends curved closer to the part of the printed-circuit board to be used. CONSTITUTION:A shape of an end of a slit 31 is composed of two kinds of different arcs. In other words, a radius of an arc closer to the PCB part to be used is relatively smaller by making it a/4 (a: width of a slit), and the radius of an arc closer to the unused part of the PCB a/2. As a result, the shortest distance between a slit 31 and another slit 31 at the bridge 4 is made closer toward the PCB part to be used than the center line of the slit 31. Therefore, a cutting line at the bridge 4 can be made closer toward the PCB to be used. As a result, the protruding length from the board to be used can be reduced. In addition, for the same size case to be used, the component mounting area on the board can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit wiring board, and more particularly to a printed circuit wiring board having an improved shape after cutting.

[0002]

[Prior Art] Modern Science Publishing CLYDE F. CO
OMBS, Jr. In the printed circuit handbook (second edition), pages 5-14 to 5-19, a method for cutting a printed circuit wiring board is explained. FIG. 4 is a top view of a conventional printed circuit wiring board provided with guide holes 2 and the like for automatically mounting components by an automatic mounting machine. The slit 3 is a hole for cutting the board, and after mounting the components, the connecting portion 4 between the slits 3 is cut to remove the unused part of the board. In cutting between the slits 3, as shown in FIG.
Since the cutting was performed by hitting the cutting line 41, approximately 1/2 of the width a of the slit 3 was projected to form a protruding portion in the peripheral portion of the substrate after cutting.

[0003]

In the conventional printed circuit wiring board, the protruding portion remaining after the cutting has been an obstacle to the miniaturization of the board. As a solution to the above problem, (1) the width of the slit 3 is made smaller than a,
(2) Bring the cutting position of the connecting portion 4 closer to the used portion side,
(3) There is a method such as inserting the slit 3 into the used portion side.

The method (1) is relatively easy to carry out for a substrate material having a low hardness such as a paper phenol material. However, in a substrate with high hardness such as copper foil fixed on both sides of a glass fiber substrate with epoxy resin, it is difficult to punch through the slit 3 with a press die from the viewpoint of mass production because of the problem of blade life. It is necessary to move the rotary blade and perform cutting, which causes a problem of long processing tact.

Further, if the width of the slit 3 is made smaller, the blade diameter a becomes smaller, so that the blade is likely to break due to lateral stress during processing, so that the processing speed must be slowed down. For example, when the plate thickness is 1.3 mm, the processing speed for the blade diameter φ2.0 is 1500 mm / min, and when the blade diameter is halved φ1.0, the processing speed becomes 3000 mm / min, and the processing efficiency is significantly reduced. Further, as described in the above-mentioned document, a cutter having a diameter of not less than a plate thickness is usually used from the viewpoint of availability of the cutter, and a cutter having a diameter of 1/8 inch is generally used for a plate having a thickness of 1.3 mm or more. Is used for.

In the method (2), since the rotary blade escapes along the arc of the slit 3 toward the shortest distance side between the arcs, that is, the central side of the slit 3, the cut surface becomes non-uniform and at the same time. There is a problem that the life of the blade is shortened. As for (3), as shown in FIG. 6, the width of the joint portion 4 needs to be cut out in excess of the blade width of the cutting machine. there were. As described above, in the conventional printed circuit wiring board, approximately half of the width a of the slit 3 remains as a protrusion in the cut joint portion 4, so that the housing for accommodating this substrate has an extra width corresponding to the protrusion width. Space was required, which was an obstacle to miniaturization and securing the component mounting area.

[0007]

In order to solve the above-mentioned problems, the end portion of the slit is formed in a shape protruding toward the use portion side of the printed circuit wiring board. For this reason, the ends of the slits have a shape in which at least two arcs having different diameters are connected to each other, and one of the two arcs having the smaller diameter is provided on the side where the printed circuit wiring board is used. Further, the slits are provided in a glass fiber double-sided board or a multilayer board.

[0008]

By cutting the portion of the slit end portion projecting toward the used portion of the substrate, the projecting width of the protrusion in the cutting portion of the substrate is reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Slit 31 according to the present invention FIG. 1 is a plan view of a printed circuit wiring board provided with a slit 31 according to the present invention. FIG. 2 is a shape diagram of the slit 31 on the coupling portion 4 side. In the present invention, the shape of the end of the slit 31 is formed by two different types of arcs. That is, the radius of the arc on the used portion side of the substrate is set to a / 4, the radius of the arc on the non-used portion side is set to a / 2, and the radius of the arc on the used portion side is made relatively small.

As a result, the shortest part of the distance between the slits 3 in the joint portion 4 is closer to the use portion side from the center of the slit 3, so that the cutting line of the joint portion 4 can be brought closer to the use portion side, and the protrusion from the substrate. The length can be reduced.
FIG. 3 is a diagram illustrating an example of a method of processing the slit 31. With a slit width of a, a hole with a φa / 2 drill is made at the position of the point X closer to the used portion, and then a cutter having a blade diameter of φa is rotated to form the slit 3.

As described above, the slit 3 has two kinds of radii.
When the arc portion 1 is formed, the portion indicated by Y in FIG. 3 is relatively swollen, so that the portion at the distance a / 4 from the used portion can be cut. The escape of the blade that cuts the slit 31 in the longitudinal direction does not pose a problem. In addition, when the cutting diameter of the cutter is increased to increase the processing speed of the slit 3, a plurality of drills are used to previously form a plurality of arcs in the arc portion of the slit 31, and the cutting position is arbitrarily set. You can

[0012]

As described above, according to the present invention, the cutting position in the connecting portion between the slits provided in the printed circuit wiring board can be brought closer to the used portion side of the substrate, so that the protrusion amount of the substrate remaining after cutting can be reduced. The substrate can be downsized. Further, the size of the housing for housing the substrate can be reduced by reducing the size of the substrate. Further, if the housing sizes are the same, the component mounting area of the board can be expanded.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of a printed circuit wiring board according to the present invention.

FIG. 2 is an enlarged view of a connecting portion in FIG.

FIG. 3 is a diagram illustrating a method of processing a slit end portion on a printed circuit wiring board according to the present invention.

FIG. 4 is a plan view of a conventional printed circuit wiring board.

5 is an enlarged view of a connecting portion in FIG.

FIG. 6 is a plan view of another conventional printed circuit wiring board.

[Explanation of symbols]

1 ... Printed circuit wiring board, 2 ... Guide hole, 3 ... Slit, 4 ... Coupling part.

Claims (3)

[Claims] 1. A printed circuit wiring board provided with a slit for cutting, wherein an end portion of the slit is formed in a shape projecting toward a use portion side of the printed circuit wiring board. 2. The slit according to claim 1, wherein the slit has a shape in which at least two arcs having different diameters are connected to each other, and one of the two arcs having a smaller diameter is a used portion of the printed circuit wiring board. A printed circuit wiring board characterized by being provided on the side. 3. The printed circuit wiring board according to claim 1, wherein the printed circuit wiring board is a glass fiber material double-sided board or a glass fiber material multilayer board.