JPS62241700A - Method of forming hole to printed wiring 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 [Technical Field] The present invention relates to a hole forming method for forming holes in a printed wiring board by punching with a press.

[Background technology]

For printed wiring boards, fiber material is impregnated with resin.
Some use a laminated plate as a substrate, which is laminated as required. The most commonly used methods for forming through-holes in this laminate are a method using a drill and a shearing method using a press or the like (punching hole processing method).

Drilling is a method that provides superior inner surface roughness and shape of the hole, but it is less efficient than the punching method. However, there is a problem that the hole machining cost is high.

If the punching method is used, complex holes such as irregularly shaped holes can be easily formed, and the cost for forming the holes is low, resulting in extremely high productivity.

However, depending on the material of the wiring board, cracks or peeling may occur between the punched holes. If the wiring board is heated and punched, the occurrence of cracking, peeling, etc. described above can be reduced, and the capacity of the press machine used for punching the holes can be reduced. As the substrate expands and contracts,
There is a problem in that the dimensional accuracy of the punched holes deteriorates. In addition, the inner surface of the punched hole becomes extremely rough, causing whitening around the hole and causing plastic failure.

[Object of the Invention] The present invention has been made in view of the above circumstances, and improves the inner surface roughness and shape of a hole drilled in a printed wiring board, and improves the processing accuracy of the hole. It is an object of the present invention to provide a method for forming holes in a printed wiring board, which improves the efficiency of hole processing, reduces the cost of hole processing, and improves the efficiency of hole processing.

[Disclosure of the invention]

In order to achieve the above objectives, the inventor conducted studies from various angles and determined that the condition (roughness and shape) of the inner surface of the hole obtained by the punching process using a press, etc. It has been found that if it is done and punched out, it will be improved.

Therefore, the present invention provides a method for forming a hole in a printed wiring board, in which the hole is punched from one side of the printed wiring board using a press punching tool, and the punching tool is reciprocated a plurality of times to punch out the hole. It is said that

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments thereof and the drawings.

Figure 1 (8) - (cl is pudding 1 - according to the present invention)
A step-by-step explanation of how to form holes in wiring boards (hereinafter simply referred to as "boards"). As shown in FIG. 1(a), the substrate 1 to be drilled is placed on a die 2-H and fixed by clamping or the like as necessary.

The die 2 is provided with a die hole 3 passing through it in its thickness direction. A punch 4, which is a punching tool, is provided above the die 2 and the substrate 1 at a position facing the die hole 3.

Next, a method for drilling holes in the substrate 1 will be explained. First, move the punch 4 downward (the movement of the punch 4 is not indicated by an arrow in the figure), as shown in Fig. 1(b).
The tip of the punch 4 presses against the substrate 1 so that it penetrates about 20% of the thickness of the substrate 1 to punch out. In this way, the hole scraps 5 of the substrate 1 bite into the die holes 3, and the displacement of the substrate 1 is prevented. After that, as shown in FIG. 1 (C1), the punch 4 is raised, and as shown in FIG. 1 Fdl, the board 1 is punched out with the punch 4.
It is designed to be driven into the die hole 3. In this manner, holes are formed in the substrate 1. The substrate 1 which has been punched is taken out by raising the punch 4, as shown in FIG. 1(e).

When the holes are processed as described above, compared to the case where the punching is performed at one time and the holes are processed, strong stress is not applied between the holes of the wiring board 1, which prevents cracks between the holes of the board 1 and the damage to the board. Peeling of the base material is less likely to occur. Plastic fracture around the hole is also less likely to occur, and the plastic fracture area is extremely small.Also, since the board 1 is not punched out at once, the punching load using the punch 4 can be reduced. , the mechanical capacity of this device can be reduced.

In the embodiment of the hole forming method according to the present invention shown in FIG. The movement is not limited to one time.It is more preferable to punch out the board in extremely small pieces to form the holes.If this is done, the above advantages will be even greater.Punching tool When the reciprocating motion is repeated more times, the finely pulverized base material powder of the board is coated on the inner surface of the hole by the punching tool.Furthermore, due to the friction between this inner surface and the tool, the inner surface is ground and finished. Therefore, it is possible to form a hole with extremely excellent inner surface roughness.

When through-hole plating is applied, the inner surface of the hole is finished neatly. For this reason, this board is prevented from causing wire breakage or blowholes, and has extremely high reliability.

Note that the hole shape is not limited to a circular cross section.
It may be selected as appropriate. For example, it may have a polygonal cross section.

As a hole forming device using the above hole forming method,
A device using a spring as shown in FIG. 2 can be considered. This device includes an upper mold 6, a lower mold 7, and a spring 8.8 that connects the upper mold 6 and the lower mold 7. Convex portions 9.9 projecting downward at both ends of the upper mold 6;
A convex portion 10 protrudes upward on the upper surface of the lower mold 7 at a position facing the
．． 10 are provided respectively. The wing 8.8 is
It is designed to fit into these convex portions 9 and 10.

In the center of the upper mold 6, there is a punch support stand 1) that protrudes downward.
A predetermined number of punches 4 are installed at the lower end of the punch support stand 1). A die 2 on which a substrate (not shown) is placed is disposed at the center of the lower die 7 facing the punch support stand 1). A die hole (not shown) is provided at a position facing the punch 4 on the die 2-E surface, and the punch 4...
This die hole is designed to fit. To make holes in a substrate using this device, the substrate to be drilled is placed on the die 2 and fixed as necessary.

This device is a hydraulic press type equipped with hydraulic oil, a hydraulic pump, etc. as a power unit. Punch 4...
Measure the sum of the maximum punching force to the base material and the total biasing force of the springs 8, 8, and hint the same value to the hydraulic control valve (relief valve, etc.). Set pressure.

In this way, when the maximum punching force of the punches 4 is generated, or when a force close to the maximum punching force is generated, the punching pressure of the punches 4 is weakened. In other words, the hydraulic oil whose pressure has increased to the set pressure is returned to the hydraulic tank via the hydraulic control valve. For this reason, the downward pressing force of the upper die 6 due to the hydraulic pressure is weakened.

Therefore, the upper die 6 is raised by the biasing force of the spring 8.8, and the tips of the punches 4 are removed from the substrate. When the upper mold 6 rises to the highest position, a detection signal is sent to the hydraulic power unit by a limit switch or the like. In other words, the upper die 6 is again pressed downward by hydraulic pressure. Therefore, the board is punched out by the punch 4. When the punching force of the punches 4 reaches the maximum value, the pressing force of the upper die 6 becomes weaker, and the punches 4 rise together with the upper die 6, as described above. The upper die 6 is repeatedly moved upward and downward, and the hole is drilled by the hydraulic press on the same surface. In other words, the hole forming process shown in FIG. Therefore, the hole drilling method using this device can produce the same effects as those detailed above.

〔Effect of the invention〕

As described above, the method for forming holes in a substrate according to the present invention includes:
Punch out the board from one side using a press punching tool,
In forming the hole, the punching tool is reciprocated multiple times to punch out the hole, so the inner surface roughness and shape of the hole to be drilled in the board are excellent, and the processing accuracy of this hole is very high. At the same time, the cost of hole machining is reduced and the efficiency of hole machining is improved.

[Brief explanation of drawings]

Figures 1(a) to (81) are cross-sectional views illustrating the method for forming holes in a substrate according to the present invention, and Figure 2 shows an embodiment of an apparatus used to carry out the method for forming holes in a substrate. It is a front view.■...Substrate 2...Dice 3...Dice hole 4
...Punching tool (punch) Agent: Patent attorney Takehiko Matsumoto Figure 1 @ Figure 2

Claims (1)

[Claims] (1) A method for forming a hole in a printed wiring board, in which the hole is punched out from one side of the printed wiring board using a press punching tool, and the punching tool is reciprocated a plurality of times to punch out the hole.