JPS62104195A - Mounting of electronic parts - 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 the Invention The present invention relates to a method for inserting and mounting an electronic component having eight leads, such as a transistor, onto a printed circuit board.

Conventional technology When inserting and mounting an electronic component with three leads, such as a transistor, onto a printed circuit board, the conventional method was as shown in Figure 4 (a).
Cut eight leads a, b, and c of electronic component A to the same length as shown in figure (b) using a cutter having a cutting blade 1 as shown in FIG. After inserting it into the back side and clinching it by bending it, the solder was fixed by dipping it with solder.

Problems to be Solved by the Invention However, according to the conventional mounting method, since the three leads a, b, and c have the same length, the printed circuit board 1
After automatically inserting into the insertion hole of 0, cut and clinch all the leads, and as shown in Figure 5, the leads a and c on both sides.
Even if the leads are bent outward in opposite directions so as not to touch each other, the middle lead b will be bent in the same direction as either lead a or lead C (lead a in the figure). If solder dipping is performed in this state, a phenomenon often occurs in which solder bridges occur between leads a and b bent in the same direction. Therefore, a repair work is required to remove the bridged solder, which requires extra effort and is extremely troublesome.

Therefore, as shown in Fig. 6 (a) and (b), solder dipping is performed with the middle lead b left protruding straight without cant-clinching it, and then the remaining length of lead b is Things like cutting and removing are being done. According to this, solder blobs between leads can be prevented, but
Correction work such as cutting the leads is required after soldering, which makes the work process complicated and has poor work efficiency.

This invention has been made in view of the above points, and has an object to eliminate the occurrence of solder blobs when inserting and mounting electronic component leads on a printed circuit board, and to eliminate the need for lead correction work after soldering. It is an object.

Means for Solving the Problems The present invention is applied when an electronic component having three leads is inserted into a printed circuit board.
The main feature is that the center lead is trimmed to the required length compared to the leads on both sides, and after inserting into the insertion hole of the printed circuit board, only the leads on both sides are crimped or clinched to perform solder dipping. There is.

Function Of the three leads, the middle lead is canted short by the required length in advance, so after inserting it into the printed circuit board, only the leads on both sides need to be bent and clinched, and the middle lead can be attached to the back side of the board. The protrusion length is suitable for solder dipping without any special processing. After that, when solder dipping is performed, the spacing between the leads becomes appropriate, so that the occurrence of solder bridges that would otherwise occur between the leads is eliminated. Therefore, there is no need for modification work to remove the solder bridging portion.

In addition, there is no need for a modification work to cut and remove the excess length of the middle lead after soldering.

Example Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the reference numeral 20 indicates leads a and b of electronic component A.
, c shows the main parts of the cutter for cutting the leads, and the receptacle for receiving the leads is equipped with a blade 21 and a cutting blade 22 for cutting the leads.

The receiver blade 21 is the receiver seat 2 where the leads a, b, and c are installed.
1a, 21b, and 21c, and is formed to have a convex cross section with a protruding ridge at the center.

The cutting blade 22 is formed to have a convex cross-section and has blade portions 22a, 22b, and 22c corresponding to the seats 21a, 21b, and 21c. The central blade part 22b connects to the central lead b,
Further, the blade portions 22a and 22c on both sides correspond to the leads a and C on both sides. The blade portion 22b is connected to the blade portions 22a and 22 on both sides.
It is located at a position that protrudes by a height d from lead c, so that the middle lead b can be cut shorter by the required length d than the leads a and c on both sides.

First, as shown in FIG. 1, the leads a, b, and c of the electronic component A are connected to the seats 21a and 21b of the blade 21.

21c, and install the blade part 22 of the cutting blade 22.
a # 22 b r 22 Read c a, b, (
to press against. Then, the leads a, b, and c are cut to a predetermined length as shown in FIG. Its length is set so that the lead b in the middle is shorter than the leads a and C on both sides by a length d.

After that, the leads a, b, and c are inserted into the lead insertion holes 101, 102, and 108 of the printed circuit board 10, and the leads a and C on both sides are bent outward in opposite directions and caulked, as shown in FIG. Make them clinch. The electronic component A is now temporarily fixed and inserted into the printed circuit board 10.

At this time, the middle lead b is left protruding straight from the back of the board, but since it has been cut shorter than the leads on both sides, its protruding length is just suitable for solder dipping. . Therefore, there is no need to perform a correction work of canting the extra length of the middle lead b after solder dipping.

Next, when soldering is performed, the leads a, b, and c on the back side of the printed circuit board are bonded to the conductor lands 111 as shown in FIG.
, 112, 113 are soldered and fixed, respectively, and the electronic component A is mounted on the printed circuit board 1o. At this time, lead b remains protruding straight, and leads a and c are bent outward in opposite directions, so that the leads do not become unnecessarily close to each other, and sufficient lead spacing is maintained. It can be kept and dipped in solder. Therefore, it becomes difficult for solder bridges to occur between the leads.

As described in detail, according to the method of the present invention, the solder bridging phenomenon that occurs between leads during solder dipping is difficult to occur and can be prevented.

In addition, troublesome and time-consuming correction work that was conventionally required, such as removing solder bridging portions after soldering dips and cutting leads, is no longer necessary, and work efficiency in component mounting can be improved.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a lead cut state of an electronic component according to the method of the present invention, FIG. 2 is a perspective view of the electronic component after lead cutting, and FIG. 3 is a sectional view showing a state in which the electronic component is mounted on a printed circuit board. Figure 4 (a). (B) is a perspective view showing the lead cutting method using the conventional method and the electronic component after lead canting, FIG. A) is a sectional view showing a state in which electronic components are mounted on a printed circuit board by another conventional method, and FIG. 6B is a plan view thereof. A......Electronic parts, a, b, c...
・Lead, 10・・・・・・・・・Printed circuit board. Patent applicant NEC Home Electro im No. 21 El Figure 3 Figure 4 (A) Figure 4 (B) Figure 5 Figure 6 (A) (B)

Claims (2)

[Claims] (1) In a method of inserting and mounting an electronic component having three leads onto a printed circuit board, the three leads are trimmed so that the center lead is shorter than the leads on both sides by the required length, and then the printed circuit board is assembled. A method for attaching electronic components that is characterized by clinching only the leads on both sides and dipping them with solder after inserting them into the device. (2) The electronic component according to claim 1, wherein the cutting length of the central lead is selected so that the protruding portion to the back surface of the printed circuit board has a length suitable for solder dipping. How to install.