JPS6234798A - Method of punching printed substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a printed circuit board punching method, and particularly to a printed circuit board punching method suitable for preventing punching defects such as large cracks.

[Background of the invention]

Conventional printed circuit board punching devices apply hydraulic holder force when punching printed circuit boards to prevent cracks, droop, and delamination that occur on the inner surface of the punched hole.

However, in the punching method of the above-mentioned punching apparatus, no consideration is given to the prevention of large-sized cracks that occur on the surface of the printed circuit board, especially when the distance between adjacent large holes is small.

In addition, in order to prevent the occurrence of cracks between holes, high temperature (60
Since the punching was performed after heating at ~80°C), there was a risk that the punching accuracy would decrease due to dimensional shrinkage due to heating.

Furthermore, conditions such as plate pressing surface pressure necessary to prevent cracks other than cracks between holes, sag, and delamination were unclear.

[Purpose of the invention]

The present invention solves the problems of the prior art as described above, and when a predetermined plate pressing surface pressure is applied when punching a printed circuit board, K
In addition to preventing the occurrence of large cracks that occur during punching, the purpose is to perform punching at room temperature, thereby eliminating the need for heating and improving die cutting efficiency and productivity. .

[Summary of the invention]

In order to achieve the above object, the present invention provides a printed circuit board punching device comprising a pump, a die, and a plate valve, in which the surface pressure of the plate valve is set to 20 inches or more of the tensile breaking strength of the printed circuit board. It is characterized by

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial sectional view of a punching device to which the punching method of the present invention is applied. In the same figure, 1 is the lower die set, 2
5 is an upper die set which is pivotally connected to a support 3 fixed on the lower die set 1 so as to be vertically movable via a spring 4; 5 is a die installed on the lower die set 1 and has a through hole 5α; 6 is a die A punch is attached to the upper die set 2 via a backing plate 7 and a punch plate 8, and the punch 6 is provided so as to face the through hole 5a. 9 passes through the backing plate 7 and the punch plate 8;
The plate valve 9 is fixed to the tip of the a-rad 10 attached to the upper die set 2, and the plate valve 9 is provided with a guide hole 9a facing the through hole 5α. 11 is a printed circuit board interposed between the die 5 and the plate valve 9; 12;
is a plate valve loading rod which passes through the upper die set 2, the backing plate 6 and the punch plate 7, and whose tip contacts the plate valve 9.

Printed circuit board punching device fK consisting of the above configuration
Therefore, when punching is performed, the punching device is installed on the press bolster (not shown), and the load (punching force) Fl necessary for punching is applied onto the upper die set 2, and at the same time, the plate valve cover is A plate valve force F2 is applied to the load rod 12. In this way, itabene force F, causes itabee? The printed circuit board 1
1, the punch 6 is pushed by the load MF1, passes through the guide hole 9α of the plate valve 9, penetrates the printed circuit board 11, and is inserted into the through hole 5α of the die 50.

In this way, predetermined holes can be punched in the printed circuit board 11.

The present invention is not affected by any loading device, and any means can be used as long as it can apply at least the punching force F1 and the plate opening crystal, such as a hydraulic double-acting press.

In the above example, the plate valve 90 surface pressure is OK"/'m
m”, printed circuit board 11) Hole diameter/board thickness (=d/l)
As a result, a crack 14 occurred in the thickness direction of the printed circuit board 11 around the punched hole 13 shown in FIG. 2. The cracks 14 reduce the electrical properties of the printed circuit board 11, especially the insulation resistance between adjacent punched holes 13.
It is considered a defective product because it causes short circuits between wires.

As a result of a detailed investigation of the punching process to determine the cause of the crack 140, it was found that when /l of the printed circuit board 11 is small, the lateral flow 15 of the material shown in FIG. The bulge 16 also becomes larger.

Therefore, the stress σθ in the circumferential direction around the hole 15 punched by the punch 6 shown in FIG.
A crack occurs and grows in the direction perpendicular to θ, and the crack 1
4 (Figure 2).

As a countermeasure against this problem, it is thought to be effective to restrain the bulge 16 around the punched hole 130 by a plate-holding force to reduce the circumferential stress σθ that causes cracks.

Therefore, we investigated the occurrence of cracks 14 (Fig. 2) by setting the clearance on one side of the punch 6 and die 5 to 5% with the punching device shown in Fig. 1 and varying the plate valve force ^, and found that Fig. 5 The results shown are obtained.

In Figure 5, the horizontal axis shows the plate valve surface pressure (9)/printed board.
The vertical axis represents the tensile breaking strength σN of the board 11 when the printed circuit board 11 is hit when the hole crack 14 occurs.
□ Temporary pressing surface pressure) is the temporary pressing force F2 applied to printed circuit board 1.
P is the value divided by the contact area between 1 and the temporary presser 9, and P is the pitch between adjacent punched holes 15 and 13.

As is clear from FIG. 5, when the temporary pressing surface pressure q is set to 20 times the tensile breaking strength σB of the printed circuit board 11, the occurrence of clarification 2140 between the adjacent punched holes 15 can be prevented.

Furthermore, regarding the area where the temporary holding effect is effective, the 6th section
As shown in the figure, a concentric protrusion 17b with a height of 1 mm% in diameter is provided on one side (printed circuit board ga) of the guide hole 17α provided in the temporary press 17 at 5, and the surface pressure of the temporary press is applied to the tensile breakage of the printed circuit board. The crack generation rate was examined by varying the diameter while keeping the strength constant at 20 inches.

The results are shown in FIG. In this figure, the vertical axis shows the crack occurrence rate (ch), and the horizontal axis shows the temporary press outer diameter CD)/guide hole diameter (d), and shows the influence of the area where the temporary press surface pressure is applied on the crack occurrence rate. It is something. The area that is effective in preventing the occurrence of curve 118Ec in the same figure is an area that is at least twice the radius of the punched hole in the printed board,
It is clear that a temporary pressing surface pressure of 20 inches or more, which corresponds to the tensile breaking strength of the printed circuit board, is required.

〔Effect of the invention〕

As explained above, according to the present invention, printed circuit boards can be punched at room temperature, so there is no dimensional shrinkage due to conventional heating, and by applying a predetermined temporary pressing surface pressure during punching, It is possible to prevent the occurrence of large cracks that occur during punching, and to improve punching dimensional accuracy and productivity.

[Brief explanation of drawings]

Fig. 1 is a partial cross-sectional view of a printed circuit board punching device to which the punching method of the present invention is applied, Fig. 2 is a plan view showing cracks that occur in the printed circuit board, and Fig. 3 is a partial cross-sectional view showing the material flow during punching. , Fig. 4 is a plan view showing the circumferential stress generated during punching, Fig. 5 is a diagram showing the incidence of Oma cracks, and Fig. 6 is a cross section of the temporary press used to change the temporary press surface pressure. 7 are diagrams showing the influence of the region to which the temporary pressing surface pressure is applied on the crack occurrence rate. 5...Die 6...Punch 9...Temporary holder 11...Printed circuit board 13...Punching holes L, X (,.

Claims (1)

[Scope of Claims] 1. A printed circuit board punching device comprising a punch, a die, and a plate holder, characterized in that the surface pressure of the plate holder is set to 20% or more of the tensile breaking strength of the printed circuit board. Board punching method. 2. Apply a board pressing surface pressure of 20% or more of the tensile breaking strength of the printed circuit board around the punched hole of the printed circuit board, in an area concentric with the punched hole and twice the radius of the punched hole. A printed circuit board punching method according to claim 1, characterized in that: