JP2838697B2 - Die-cutting method for through-hole part of double-sided printed circuit 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 method for cutting and cutting through holes in a double-sided printed circuit board for a small electronic device such as a continuous shooting type still camera, a DVD type video device and a portable telephone.

[0002]

2. Description of the Related Art As a conventional technique of this kind, a required circuit pattern is formed on each of the front and back surfaces of a reinforced plastic substrate containing glass fiber as an insulating substrate constituting a printed circuit by using a printing method or an etching method. The conductive lands on the front and back of the substrate are electrically connected to each other via a conductive layer plated on the inner peripheral surface of the small hole of the substrate, usually called a through hole.

[0003] In view of the restrictions on the shape and size of the circuit board and the difficulty of pin passing when implanting pin terminals in the through-hole conductive portion, the lower die is placed at the center of the through-hole conductive portion. Was cut by vertical push-cutting with a flat single-edged cutting tool provided on the upper die.

[0004] The above-mentioned conventional technique is, in particular, shearing of a through-hole conductive portion of a tough substrate by a flat blade.
The direct type shear stress and impact force are greatly applied to the inner peripheral edge of the through hole straight, and fine cracks occur in the plating layer on the inner peripheral surface of the through hole, leading to poor conduction between the conductive lands on the front and back, and around the through hole. Conductive lands often peel off, resulting in low product yields and high costs.In the middle of use, it is difficult to secure the conductivity of the through-hole conductive parts, making it unstable and causing many market complaints for the equipment used. There was a problem that.
Therefore, as a cutting method that overcomes the above problems, a method described in Japanese Patent Application Laid-Open No. 8-32202 previously proposed by the present applicant is also known.

In this prior art, the printed circuit board on the lower die is connected to the blade plate of the upper die from the center of each of a plurality of through-hole conductive portions for conducting conductive lands formed on the front and back surfaces of the printed circuit board. In the method of cutting off by cutting, the edge shape of the blade plate has a flat surface on one side of the blade plate and a clipper-tooth-shaped single-blade structure in which a bilaterally symmetrical saw-tooth-shaped blade is protruded from the center at the lower portion of the other surface. The through-hole conductive portions are centered by respectively lowering the respective tips of a plurality of continuous parallelogram-shaped bevel slopes formed continuously in the thickness oblique direction from the center of the through-hole conductive portion. From a through-hole portion of a double-sided printed circuit board that can be cut obliquely from the edge of the cutting edge toward the periphery.

[0006]

According to the above prior art,
Since the through-hole conductive portion can be sheared obliquely by pushing (knife cutting) between the cutting edge slope and the edge of the lower die from the center to the periphery of the through-hole conductive portion, unreasonable direct-type shear stress is applied to the through-hole conductive portion. This has the advantage that the conductive plating layer on the inner surface of the through hole does not crack or the conductive land does not peel off.However, cutting chips stick to the valleys of the clipper-like blades, causing cutting burrs and uneven shearing accuracy. However, in order to repair the wear of the cutting edge slope by polishing, it is troublesome with fine work and requires skill, and the number of times of polishing is also limited by itself. There is an essential problem that it becomes useless.

In order to eliminate the above-mentioned problems, the present invention protects the inner peripheral surface of a conductive portion by inserting a pin into a through-hole conductive portion of a double-sided printed circuit board in advance, and then removes the circuit board from the center. An object of the present invention is to prevent excessive direct-type shear stress from being applied to the through-hole conductive portion by cutting, and to enable the upper and lower blades to be repeatedly polished and used.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a printed circuit board having a plurality of conductive lands formed on a front surface and a back surface of a printed circuit board. In cutting the substrate on the male blade mold of the lower die with the female blade mold of the upper die from each center of the through-hole conductive portions of the row, the lower part of the upper die lowers the trueness into the through-hole conductive portions. After protecting the inner peripheral surface of each through-hole conductive part by inserting a guard pin from above, the blade edge of the female blade is lowered from the die-cutting contour line connecting the centers of these through-holes, and the circuit board is female. This was achieved by cutting the mold at the same time as shearing with the cutting edge of the cutting die and the cutting edge of the male cutting die. Further, the die on the substrate on the lower die may be cut out while being elastically lowered by an elastic body which elastically descends with the upper die.

[0009]

Embodiments of the present invention will be described with reference to the drawings. First, the basic form of the present invention is:
As shown in FIGS. 1 to 3, conductive lands 2, 2 formed by well-known means are electrically connected to the front and back surfaces of a printed circuit board 1 made of reinforced plastic containing glass fiber, synthetic carbonate resin, or the like. In order to make external connection, a plurality of rows of through-hole conductive portions 3 and 3 formed along, for example, a square die-cut contour line L which is slightly smaller than the substrate 1 are formed with a conductive film by known electroless multilayer gold plating or the like. .

Next, in order to cut the circuit board 1 from each center O of the conductive portions 3 and 3 and at the same time to cut the die from the cut contour line L, the circuit board 1 is protruded from the lower die 4. After strictly positioning and placing the pilot hole PL of the substrate 1 into a known pilot pin, for example,
As shown in FIG. 1 and FIG. 4, a female blade die 7 fixed to the upper die 6 with a screw n and a male blade die 5 of the lower die 4 are pushed off, that is, sheared and simultaneously punched out as a product. Configure.

The female blade mold 7 has a substantially hole-shaped punching hole in the plane, and as shown in FIGS.
The vertical spacer 6A, the pushing plate 6B for pushing down the guard pin P, and the hanging plate 6C for the guard pin P are sequentially interposed and firmly fixed with a long screw n. It is designed to go up and down.

And, of course, the guard pin P
In each of the cutting edge surfaces of the cutting edge 7a of the female cutting die 7 and the cutting edge 5a of the male cutting die 5 of the lower die 4 in the peripheral part of the above, a guard pin negative groove m for each semicircle for guiding and rubbing the guard pin P is formed. Each of the blade edges 5a and 7a has a plane shape that matches the die-cut contour line L, and is 2 to 3 μm from each other.
The substrate 1 is sheared vertically in the extremely small gap, and the substrate 1 is sheared.

In the illustrated example, the guard pins P are inserted and the circuit board 1 is pushed off while the circuit board 1 is pressed against the upper surface of the lower die 4 by the elastic body 8.

That is, the resilient body 8 is a flat rectangular parallelepiped metal plate, and a semicircular pin-negative groove m which does not hinder the lifting and lowering of the guard pin P is formed on the sliding contact surface of the female blade mold 7 as shown in FIGS. 4 and the four corners of the resilient body 8 are attached to the guard pin suspension plate 6C by the four suspension bolts 9 in FIG.
And hang it as shown.

Next, the guide holes (not shown) of the guard pin suspending plate 6C and the guard pin pushing plate 6B are freely inserted near the inside of the four corners of the upper surface of the resilient body 8 as shown in FIG. The knock pins 8A are planted as shown in FIGS. 1 and 3, and a push plate 8B is placed on the upper end of each pin 8A, and urethane is placed between the upper surface of the push plate 8B and the lower surface of the upper die 6. An elastic body 10 such as a synthetic rubber column such as rubber or a coil spring is interposed.

Then, the upper surface of the circuit board 1 on the lower die 4 is strongly pressed against the upper surface of the lower die male blade mold 5 by the elastic force of the elastic member 8 passing through the knock pin 8A by the compression elastic repulsion of the elastic body 10. The circuit board 1 with the circuit board 1 immobilized and stabilized
Can be sheared.

When the circuit board 1 is sheared, the elastic pressure seat 4A in which a pin long groove m which does not hinder the lifting and lowering of the guard pin P is cut as shown in FIGS. And the other elastic member 10 of the same material
(B) and (c) in FIG. 4 when the substrate is cut along with the lowering of the female blade die 7 and the guard pin P at the peripheral position of the female blade.
As shown by, the guard pin P is guided downward, and the substrate is cut while holding the unnecessary side substrate being cut between the lower surface of the cutting edge and the resilient seat 4A.

Further, according to the present invention, even if a shock is applied to the through-hole conductive portion 3 at the moment of the above-mentioned pushing-off of the circuit board 1, the conductive film is prevented from cracking or peeling accident. Immediately before cutting the circuit board 1, FIG.
The guard pin P, which protrudes downward from the guard pin suspension plate 6C through the states of FIGS. 5A and 5B in FIG. 5, is used as a female blade as shown in FIGS. It is inserted into the through-hole conductive part 3 prior to the mold 7.

By this insertion, the outer peripheral surface of the guard pin P is appropriately pressed against the inner peripheral surface of the through-hole, and it is possible to protect the inner peripheral surface of the through-hole conductive portion 3 from external shock while holding it down. Immediately afterward, the female blade mold 7 is lowered from the die contour L connecting the centers O, O of the through-hole conductive parts 3, 3 as shown in FIGS. 3, 4, and 5 (d). The circuit board 1 is divided into a male blade edge 7a and a male blade edge 5a of the lower die 4 from the contour line L connecting the center lines O, O of the through-hole conductive portions 3 in FIG. As shown in each figure, you can push it cleanly, and then
3, 4 and 5, the upper die 6 was raised together with the female blade die 7 to obtain a four-side cut product A as shown in FIG.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of pilot holes PL are formed in a circuit board 1 and these pilot holes PL are tightly inserted into pilot pins (not shown) of a lower die 4 or the like.
When the positioning and the reliable localization are performed by well-known means, the circuit board 1 can be cut sufficiently by the positioning and localization alone, and the knock pin 8A related to the elastic body 8 including the elastic body 8 as well. Press plate 8B and elastic body 1
0 can be made unnecessary.

In each of the above examples, the through-hole conductive portion 3 and the guard pin P are each circular, but the planar shape of the through-hole conductive portion 3 may be various shapes such as a square, an oval, and an ellipse. But the guard pin P
The cross-sectional shape of each of the through-hole conductive portions 3 naturally matches the planar shape of each through-hole conductive portion 3. In addition, as a result of an experiment, the clearance between the inner peripheral surface of the through-hole conductive portion 3 and the outer peripheral surface of the guard pin P has a gap of about 20 μm. The surrounding surface could be protected.

[0022]

As described above, the present invention has the following advantages. In order to electrically connect the conductive lands 2 and 2 formed on the front and back surfaces of the printed circuit board 1 to each other for external connection, the center of each of a plurality of rows of through-hole conductive portions 3 and 3 formed along the cut contour L From O, the substrate 1 on the male blade mold 5 of the lower die 4 is replaced with the female blade mold 7 of the upper die 6.
When the upper die 6 is lowered, a guard pin P is inserted into the through-hole conductive portion 3 from directly above the lower die 6 to protect the inner peripheral surface of each of the through-hole conductive portions 3. The blade edge 7a of the female blade mold 7 is lowered from above the die-cutting contour line L connecting the centers O of these through holes, so that the circuit board 1 is mounted on the blade edge 7a of the female blade mold 7 and the blade edge of the male blade mold 5. 5a and the die were cut at the same time.

Therefore, according to the present invention, no excessive direct-type shear stress is applied to the through-hole conductive portions 3, 3.
The outer peripheral surface of the guard pin P can be abutted and protected on the conductive plating layer on the inner peripheral surface of the through-hole, and the cracking of the conductive plating layer and the separation of the conductive land do not occur. This has many effects, such as reduction in the number of layers, and even during use, the continuity of the through-hole conductive portion can be stably ensured for a long period of time.

Further, in the present invention, the blade edge 5a of the male blade mold 5 and the blade edge 7a of the female blade mold 7 are each a substrate shearing due to the mutual difference between the right-angled long edges. There is also a benefit that polishing can be repaired as much as possible.

According to the second aspect, after the circuit board 1 is positioned on the lower die 4, the position of the circuit board 1 is elastically localized by the elastic body 8 so that the circuit board 1 is automatically immobilized. In addition to simplifying the means for temporarily fixing the circuit board 4 to the circuit board 1, the industrial effect of improving workability can be added.

[Brief description of the drawings]

FIG. 1 is an enlarged elevation view of a main part cutaway showing an example of an embodiment of the present invention.

FIG. 2 is a plan view showing an example of a double-sided printed circuit board before die cutting.

FIG. 3 is a vertical sectional view of a main part showing a cutting order of a substrate according to the present invention.

FIG. 4 is a vertical sectional side view of a main part showing a cutting order of a substrate according to the present invention.

FIG. 5 is a vertical sectional side view of a main part showing a cutting order of a substrate according to the present invention.

FIG. 6 is a cross-sectional plan view of the main part of what is shown in FIG. 1;

FIG. 7 is a plan view showing an example of a die-cut product of a printed circuit board.

[Explanation of symbols]

 P Guard pin for protecting the inner peripheral surface of the through-hole conductive part L Die-cut contour line as a product 1 Double-sided printed circuit board 2 Conductive land 3 Through-hole conductive part O Center of through-hole conductive part 4 Lower die 5 Male blade type 5a Male blade type Blade edge 6 Upper die 7 Female blade type 7a Female blade type blade edge 8 Resilient body 9 Elastic suspension bolt 10 Elastic body such as urethane rubber m Guard pin strip

Claims (2)

(57) [Claims] 1. A plurality of rows of through-hole conductive portions 3 formed along a cutout contour line L for conducting conductive lands 2 and 2 formed on the front and back surfaces of a printed circuit board 1 for external connection. , 3 from the center O, the lower die 4 male blade mold 5
In the method of cutting the upper substrate 1 with the female die 7 of the upper die 6, as the upper die 6 is lowered, the guard pins P are inserted into the through-hole conductive portions 3 from directly above the respective through-holes. After protecting the inner peripheral surfaces of the conductive portions 3, 3, the blade edge 7 a of the female blade mold 7 is lowered from above the die-cutting contour line L connecting the centers O of these through holes, and the circuit board 1 is A cutting method for cutting a through-hole portion of a double-sided printed circuit board, wherein the cutting is performed simultaneously with the shearing of the blade edge 7a of the mold 7 and the blade edge 5a of the male blade mold 5. 2. The circuit board 1 on the lower die 4 is attached to the upper die 6.
The guard pin P is inserted and the circuit board 1 is pressed while being pressed onto the lower die 4 by an elastic body 8 which elastically descends as the armature descends.
2. The method according to claim 1, further comprising the step of: