JPH104251A - Manufacturing method of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cut off an endface through hole printed wiring board without releasing a metallic film by cutting off the board after the formation of a spare trench of the trench section along a contour line from the two positions whereon the contour line of the end face through hole are traversed. SOLUTION: An end face through hole 4 is provided along the contour line 3 of a printed wiring board 2 in a substrate 1 to form a metallic film 6 of a circuit pattern of the adjacent printed wiring board. Next, a spare trench 7 in V type long trench shape is formed on one face along a contour line 3 on the two positions whereon the contour line 3 of the end face through hole 4 is traversed. Next, the end face through hole printed substrate 2 is cut off from the substrate 1. Through this cutting off step, the release, falling off and burring of the metallic film 6 formed on the inner wall surface of the end face through hole can be avoided.

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 an end face through-hole printed wiring board for preventing peeling of a metal film on an inner wall surface of an end face through hole.

[0002]

2. Description of the Related Art Usually, a printed circuit board is formed by arranging a large number of printed circuit boards on a board formed of an insulating material.
It is manufactured by cutting along its outline. Conventionally, a printed circuit board having an end face through hole is formed by drilling an end face through hole on a board at a required position along the outer shape of the printed board, and then applying electroless plating to the board to obtain a substrate surface and an end face. A metal film (foil) is formed on the inner wall surface of the through hole, a wiring pattern is formed, and after solder resist processing,
It is manufactured by cutting this board to the size of a printed board with a press or a router.

[0003] In such a cutting method in the manufacture of an end face through-hole printed wiring board, the end face through hole portion is subjected to a strong stress at the time of press or router processing. Therefore, there is a problem that the metal film formed on the inner wall surface of the end face through hole is peeled off from the insulating material as a substrate material, drops off, becomes burr, and requires a defective product or a rework process. is there. As a solution to the problems associated with the peeling of the metal film, two holes crossed by the outline of the through hole at the end face are drilled by rotating in a direction in which the metal film on the inner surface is pressed against the substrate material, and then pressed. (Japanese Patent Laid-Open No. 4-350)
No. 86). However, according to the above-described method, two steps of drilling are required before cutting, which requires careful attention in the rotating direction, lowers productivity, increases costs, and reduces the amount of drilling chips. There is a problem that a removing step is required.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a printing method for cutting an end face through-hole printed board from a board by a simple method without peeling a metal film formed on the inner face of the end face through hole. An object of the present invention is to provide a method for manufacturing a wiring board.

[0005]

Under such circumstances, the present inventors have made intensive studies and, as a result, completed the present invention.

That is, the present invention relates to a method of cutting a printed circuit board having an end face through-hole having a metal film formed on an inner wall surface along an outline to be cut, the method comprising the steps of: The present invention provides a method for manufacturing a printed wiring board, characterized in that a preliminary groove having a V-shaped or U-shaped groove cross section is formed along the outer shape line, and then the cutting is performed.

According to the method of manufacturing a printed wiring board of the present invention, a V-shape or U-shape formed by preliminary groove processing such as a tip saw or a foil saw at a position where an end face through hole such as a small round hole or a long hole is sheared. Due to the U-shaped grooves, the stress of the press is concentrated on the cut portion when cutting by a press or the like thereafter, so that the cutting is performed without the metal film peeling from the substrate material. In addition, the preliminary groove processing can be performed without paying special attention to the positioning of the preliminary groove by performing preliminary groove processing on a long groove shape, for example, a straight line portion along the external line from two places crossed by the external line of the end face through hole. it can.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the method for processing the preliminary groove is not particularly limited, but is a step after forming a wiring pattern by etching and performing solder resist processing, using a chip saw or a foil saw. It is particularly preferable to use a wheel saw having a continuous blade, since a uniform distribution of the cutting stress at the time of processing can be achieved. The rotation direction (processing direction) of the tip saw or the wheel saw is not particularly limited, and is performed in one direction in which processing is performed from left to right or right to left or in each direction in which the metal film on the inner wall surface is pressed against the inner wall surface. Any one of the directional processing may be used, but the one-directional processing is preferable because only one step is required.

In the present invention, it is necessary that the cross-sectional shape of the preliminary groove is V-shaped or U-shaped. In particular, it is preferable that the pre-groove be U-shaped by a foil saw having a continuous blade. It is preferable because it disperses stress. Also,
The length, the depth and the width of the preliminary groove are not particularly limited, and the cutout groove shape may be formed along the outline from two places where the outline of the end face through hole crosses.
A long groove shape may be formed to process all the straight line portions of the outer shape line. However, a long groove shape is particularly preferable since a load is reduced when the outer shape portion is punched and the entire cut surface can be cut cleanly. The notch groove preferably has a width and depth of about 0.3 to 0.5 mm, respectively, and the long groove preferably has a U-shape having a width of about 0.3 to 0.5 mm. .

In the present invention, the preliminary groove processing can be performed from one side or both sides.

Next, an embodiment of a method of manufacturing an end face through-hole printed wiring board according to the present invention will be described with reference to FIGS. FIG. 3 is an explanatory view showing a printed board having an end face through-hole in which a metal film is formed on an inner surface along an outline cut from the board. That is, FIG.
FIG. 4 is a view showing a state before performing preliminary groove processing. In FIG. 3, an end face through-hole 4 provided along an outline 3 of a printed board (small board) 2 in a board 1 is formed by a process similar to that of the related art in a circuit pattern of a printed board adjacent to the end face through hole 4. The metal film 6 is also formed on the inner surface (vertical surface) of the end face through hole 4. 2 that the outline 3 of this end face through hole 4 crosses
At a location, as shown in FIG. 1, a V-shaped long groove-shaped spare groove 7 was formed on one surface along the outline 3. Such a preliminary groove was formed by counterclockwise rotation while moving from the right side to the left side of the drawing by the tip saw A. Thereafter, the end-face through-hole printed board 2 was cut off from the board 1 by pressing. At the time of this excision, the stress of the press working was concentrated on the notch of the V-shaped groove, and the metal film did not peel off from the base material.

FIG. 2 shows a spare groove 8 having a U-shaped cross-section and a long groove formed along a contour line 3 with a foil saw B, and has the same operation and effect as described above.

[0013]

According to the method of the present invention, two cross-sections of the cut-out outline of the end face through-hole are preliminarily grooved with a V-shaped or U-shaped cross section. The metal film formed on the inner wall surface of the hole does not peel, fall off, or generate burrs. Further, the method of the present invention can minimize the increase in cost only by adding a simple step.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an end face through-hole portion preliminarily grooved by a tip saw.

FIG. 2 is a perspective view of a main part of an end face through-hole portion of another example in which a preliminary groove is formed by a wheel saw.

FIG. 3 is a plan view of a main part of the substrate on which an end face through hole is formed.

[Explanation of symbols]

 Reference Signs List A Chip saw B Wheel saw 1 Board 2 Printed circuit board 3 Outline line 4 End face through hole 5, 6 Metal film (foil) 7, 8 Spare groove

Claims (3)

[Claims] 1. A method for cutting a printed circuit board having an end face through-hole having a metal film formed on an inner wall surface along an outline to be cut, comprising: A pre-groove having a V-shaped or U-shaped groove cross section along the line, and then performing the cutting. 2. The manufacturing method according to claim 1, wherein said preliminary groove processing is performed to form a long groove having a U-shaped groove cross section. 3. The method according to claim 1, wherein the preliminary groove processing is performed on one surface or both surfaces.