JPS63217694A - Manufacture of printed wiring board - 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] [Industrial application field]

The present invention relates to a method of manufacturing a through-hole printed wiring board having circuit patterns on both sides, and more particularly to a method of manufacturing a double-sided printed wiring board in which holes for inserting retrofitted components are not buried in solder.

[Conventional technology]

A conventional double-sided printed wiring board has a structure in which conductive circuit patterns are formed on both the front and back sides of an insulating substrate, and a component insertion hole is drilled in the center of a land that becomes the soldering part of these circuit patterns. The component insertion hole is a so-called through hole in which a conductive plating layer is formed on the inner peripheral surface to electrically connect with the land. and,
When mounting components, insert circuit elements such as resistors and transistors into the above-mentioned through holes, immerse the printed wiring board in this state in a flux bath, and then immerse it in a solder bath to connect the legs of the circuit elements to the above-mentioned lands. Then, after cutting off the legs of the circuit element with a cutter, the flux was removed by cleaning with Freon. However, when the above-mentioned circuit element elements are relays, buzzers, switches, etc., the above-mentioned freon cleaning cannot often be performed. After cleaning, it was manually inserted into the through hole and soldered. For soldering, it is necessary to take measures to prevent the through-holes for inserting retrofitted components from being buried by solder during the soldering process of the retrofitted components, otherwise the retrofitted components will mount. The problem was that it couldn't be done. Therefore, in conventional single-sided printed wiring boards, as shown in FIG. By forming the slits 3b at the same time, the land 3a with the slits was prevented from being buried. That is, the slit land 3a has its slit 3b.
Therefore, even if the printed wiring board is immersed in a solder bath, the component insertion hole 2 surrounded by the slit land 3a is not filled with solder.

[Problems to be solved by the invention]

However, the above-mentioned measure to prevent solder from being buried in the component insertion hole 2 by the land 3a with slits of the single-sided printed wiring board is to prevent the solder from being buried in the component insertion hole 2 by using the land 3a with the slit on the single-sided printed wiring board. It could not be used for through-holes for physical connections. In other words, in the case of a through hole, even if the lands connected to both ends are lands with slits, the surface tension of the conductive plating layer on the inner circumferential surface of the through hole causes solder to stick inside the through hole and form the hole. result. Therefore, in the case of double-sided printed wiring boards having through-holes, the following measures have been taken before mounting retrofitted components as a means to prevent solder from burying the through-holes. ■ Mask the solder surface with tape and remove the masking tape after automatic soldering. ■Fill the hole with adhesive and after automatic soldering,
Peel off the adhesive. ■Print adhesive and peel it off after automatic soldering. ■Insert a toothpick etc. into the hole in the place to prevent solder embedding. However, in either case, there is a problem in that it requires a considerable amount of effort and work efficiency is extremely low. This invention was made in order to solve the above problems, and it is possible to easily obtain the function of preventing solder from being buried in the retrofitting component insertion hole.
To prevent solder embedding, you can use it without any effort.
It is an object of the present invention to provide a method for manufacturing a through-hole double-sided printed wiring board that allows mounting of retrofitted parts easily and efficiently.

[Means to solve the problem]

The method for manufacturing a printed wiring board according to the present invention includes the steps of forming a through hole at a location for inserting a pre-installed component in an insulating substrate having a circuit pattern formed on both the front and back sides, and forming a slit at a location for inserting a post-install component on the circuit pattern. The present invention is characterized by comprising a step of forming a land, and a step of forming a non-conductive retrofit component insertion hole surrounded by the slit land in the insulating substrate.

[For use]

In the printed wiring board manufacturing method of the present invention, in addition to the through-hole for inserting the pre-attached component formed in the insulating substrate, a land with a slit is provided at the post-attached component insertion portion of the circuit pattern.
A non-conductive retrofitting component insertion hole is formed surrounded by this slit land. Therefore, the double-sided printed wiring board obtained by the method for manufacturing a printed wiring board of the present invention has the following features: the retrofitting component insertion hole other than the through hole does not have a conductive layer, and the land surrounding the retrofitting component insertion hole By forming the land with a slit, it is possible to reliably prevent the retrofitting component insertion hole from being buried by the solder when soldering the preattached component, and it is possible to easily and efficiently mount the component.

【Example】

Hereinafter, one embodiment of the present invention will be described based on the drawings. FIGS. 1(a) to 1(e) are manufacturing process diagrams of a printed wiring board according to an embodiment of the present invention, and the same or equivalent parts as in FIG. 4 are given the same reference numerals. The insulating substrate l shown in FIG. 1(a) is shirred in advance to a predetermined size, and the insulating substrate 1 is first shirred as shown in FIG. 1(b).
A hole 2 for forming a through hole is bored as shown in FIG. Next, as shown in FIG. 1(c), the front and back surfaces of the insulating substrate 1, including the inner peripheral surface of the hole 2, are plated to form a front conductive layer 3 and a back conductive layer for forming a circuit pattern. 4 and a through hole 2a for inserting a pre-attached component. Thereafter, as shown in FIG. 1(d), by etching and removing the conductive layer portions of the front conductive layer 3 and the back conductive layer 4 other than the circuit pattern forming area, the conductive layer 3.4 in the circuit pattern forming area is removed. It is formed as a circuit pattern 3.4. In the etching process, a slit land 3a having the same slit 3b as in the case of FIG. 4 is simultaneously formed on one side of the insulating substrate 1, which is the component side, at the position where a retrofitted component is inserted in the circuit pattern 3. Form. Next, as shown in FIG. 1(e), a post-installation component insertion hole 5 is bored in the insulating substrate 1, passing through the center of the slit land 3a. Here, when it is necessary to directly turn the legs of the retrofitted component inserted into the retrofitted component insertion hole 5 onto the component surface of the printed wiring board, as shown in FIG. A through hole 2a for inserting a pre-attached component may be formed in the vicinity of the through hole 2a. Further, as shown in FIG. 3(a), the retrofitting component insertion hole 5 is formed as a through hole, and then in the final step of pressing, in which the outer shape and mounting holes of the printed wiring board are simultaneously punched out, a third step is performed. As shown in Figure (b), the post-installation component insertion hole 5 may be formed by simultaneously punching out the central portion of the slit land 3a and removing the through-hole plating.

【Effect of the invention】

As described above, according to the present invention, there is a through-hole for inserting a pre-attached component, a land with a slit at a location for inserting a post-attached component, and a non-conductive retro-fit component insertion hole passing through the center of the land with a slit. Since the retrofitting component insertion hole, which is separate from the through hole, does not have a conductive layer, and the land surrounding the retrofitting component insertion hole is a land with a slit, it is possible to The retrofitting component insertion hole is not buried by the solder when soldering the attached components, and the burying prevention effect is reliably obtained, so there is no need to take conventional, time-consuming and complicated burying prevention measures. Component mounting can be done easily and efficiently.

[Brief explanation of the drawing]

1(a) to (e) are sectional views showing the manufacturing process of a printed wiring board according to one embodiment of the present invention, FIG. 2 is a sectional view of essential parts of a printed wiring board according to another embodiment, and FIG. Figure 3(a),
(b) is a sectional view showing a partial manufacturing process of a printed wiring board according to yet another embodiment, and FIG. 4 is a plan view showing a conventional single-sided printed wiring board. In the figure, 1 is an insulating substrate, 2a is a through hole, 3,
4 is a circuit pattern, 3a is a land with a slit, and 5 is a hole for inserting a retrofitted component.

Claims (3)

[Claims] (1) Forming circuit patterns on both the front and back sides of the insulating substrate,
A method for manufacturing a printed wiring board provided with through-holes for electrically connecting those circuit patterns, which includes a step of forming a through-hole at a location where a pre-installed component is inserted in the insulating substrate, and inserting a post-install component of the circuit pattern. A method for manufacturing a printed wiring board, comprising the steps of: forming a land with slits at a location; and forming a non-conductive retrofitting component insertion hole surrounded by the land with slits in the insulating substrate. . (2) The method for manufacturing a printed wiring board according to claim 1, wherein the slit land is formed only on one side of the insulating substrate on the soldering side. (3) A drilling process for forming a through hole in the insulating substrate, a plating process for forming a conductive layer on both the front and back surfaces of the insulating substrate and the inner surface of the hole, and a circuit pattern forming area on both sides of the insulating substrate. An etching process that removes the other conductive layers and forms a soldering land at the location where the pre-attached component will be inserted and a land with a slit at the location where the retrofit component will be inserted, and a non-conductive post-etching process on the insulating substrate at the slit land portion. The method of manufacturing a printed wiring board according to claim 1, further comprising the step of forming an attachment hole.