JPH02243296A - Shape processing method for printed-wiring board - Google Patents

Abstract

PURPOSE:To reduce both cuttings and nap in machining as well as to enhance accuracy in finish by primarily blanking a board out by the use of an upper metal mold with a cutting edge angle of 90 deg., and thereby subsequently finishing the cross section and shape of the board by the use of an upper metal mold with a cutting angle less than 90 deg.. CONSTITUTION:A printed wiring board 1 is primarily blanked out by the use of an upper metal mold 4 with a cutting edge angle theta of 90 deg., then, subsequently the board is secondarily blanked out along the shape processing line of the printed-wiring board 1 by the use of an upper metal mold with a cutting angle thetaless than 90 deg. so that the cross section and shape of the printed-wiring board is thereby trued. As a result, it is possible to reduce cuttings and nap in machining.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for processing the outer shape of a printed wiring board used for assembly and wiring of electronic devices.

(Conventional technology) In recent years, due to improvements in surface mounting technology and demands for cost reduction, ceramic substrates on which semiconductor elements are mounted have been replaced.
Printed wiring boards, in which semiconductor elements are directly mounted on a substrate made of glass epoxy or the like, have come into use.

Such printed wiring boards have been manufactured using the following processing method.

■ Router processing is used to perform cutting and contour processing using an end mill.

■ A punching press process that uses upper and lower dies to punch out in one step.

When using router processing as described in (■) above, there is less adhesion of fluff and cutting powder on the board, but the cost is high, and if there is a conductor such as a through hole on the outline of the board, the disadvantage is that the conductor is likely to turn over. there were. In addition, in the case of (2) punching press processing, although the cost is low, there are disadvantages in that the cutting powder and fluff of the substrate are often generated and the conductor is often turned over.

(Problem to be solved by the invention) However, in recent years, as chip-shaped parts are mounted directly on the board or incorporated, it is necessary to avoid cutting powder, fluff, and curling of conductors generated from the board itself during external processing. There has been a strong demand for strict specifications such as extremely small quantities and low prices.

The present invention aims to provide an external finishing method for realizing a printed wiring board that solves these problems.

[Structure of the Invention] (Means for Solving the Problems) The finishing method for a printed wiring board of the present invention has a cutting edge angle of 9
It is characterized by performing primary punching using an upper die of 0 degrees, and then performing secondary punching to remove the resulting fluff in the cross-sectional view of the board using an upper die having an edge angle of less than 90 degrees to finish the cross section and outer shape.

(Function) In the printed wiring board according to the present invention to which such a finishing method is applied, secondary punching is performed using a die with a cutting edge angle of less than 90 degrees, so cutting dust and chips generated from the board itself are eliminated. It generates very little fluff and almost no curling of conductors, and can be used in place of ceramic substrates on which semiconductor elements are directly mounted.Furthermore, it can perform finish cutting in multiple locations at the same time with a single punching action. It has the great advantage of being low cost.

(Example) Hereinafter, an example of the printed wiring board finishing method according to the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram showing the relationship between a printed wiring board, an outline line, and an outline processing line in an embodiment of the present invention, and FIG. 2 is a partial cross-sectional view of a primary punching die used in an embodiment of the present invention. FIG. 3 is a partial sectional view of the secondary punching die.

The outer contour machining line 3 with a cutting allowance of about 0.05 to 0.2 degrees from the contour line 2 of the printed wiring board 1 is cut into the usual molds shown in FIG. 2, that is, the upper mold 4 and the lower mold. 5, and the primary punching is performed using a mold in which the blade angle θ of the upper mold is 90 degrees.

This printed wiring board, which has been punched out, is put into a mold with a sharp blade angle as shown in Fig. Board thickness 1
．． Secondary punching is performed on the outline 2 of the printed wiring board 1 using a mold having a blade angle of about 80 degrees (in the case of 8 mm).

Through this secondary punching, the outer shape of the printed wiring board is precisely aligned, and the cutting powder of the printed wiring board generated during the secondary punching, the length of the printed wiring board cross section is 0.1 to 0,3 mta. The fluff, etc. of the insulator is removed, and the curling of the conductor that has already occurred is removed.
All metal fuzz smaller than u is removed.

As a result, fluff and curling of conductors on the printed wiring board after secondary punching are extremely reduced, making it possible to obtain a printed wiring board that satisfies the strict specifications required for printed wiring boards on which semiconductor elements are directly mounted.

The printed wiring board produced by the finishing method according to the present invention has sufficient accuracy for practical use, and can be completed in an extremely short time by punching, so it is approximately three times smaller than the conventional router processing method.
could be manufactured at a price of

[Effects of the Invention] According to the present invention, primary punching is performed using a punching press that has been widely used in the past using a top mold with a normal blade angle of 90 degrees, and then a top die with a blade angle of less than 90 degrees is used. Since it is constructed by finishing the cross section and external shape using a mold, it produces less cutting dust and fluff, has high reliability with no damage to the conductive holes, and is a printed wiring board on which semiconductor elements can be directly mounted. It is possible to obtain a printed wiring board that satisfies specifications, has high finish accuracy, and is priced at a fixed price.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the relationship between a printed wiring board, an outline line, and an outline processing line in an embodiment of the present invention, and FIG. 2 is a partial cross-sectional view of a primary punching die used in an embodiment of the present invention. FIG. 3 is a partial sectional view of the secondary punching die. 1・・・・・・・・・Printed wiring board

Claims (1)

[Claims] When punching printed wiring boards, an upper die with a blade angle of 90 degrees is used to temporarily punch out, and the resulting fuzz on the cross section of the board is removed by secondary punching using an upper die with a blade angle of less than 90 degrees. A printed wiring board outer shape processing method characterized by finishing the outer shape.