JPS5972793A - Method of soldering circuit part - 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 Industrial Application] The present invention relates to a method for soldering circuit components, in which lead wires t of circuit components are soldered to wiring patterns on a printed circuit board.

[Background technology and its problems]

Normally, when soldering lead wires of circuit components (IC, modicoll, resistor, capacitor, etc.) to the wiring pattern of a printed circuit board, holes 2 are made in the printed circuit board 1 from the pattern side of the printed circuit board 1 as shown in Figure 1. to, for example, IC5+
1', and a plurality of horizontally extending lead wires drawn out substantially parallel to the predetermined wiring pattern 3 and the printed circuit board 1 are made to face each other. Then, the wiring pattern 3 and the lead wire 6 are soldered by the solder dip method.

At this time, when the printed circuit board 1 and the IC 5 are soldered into the molten solder 8 in the static solder bath, the molten solder 8 flows onto both sides of the IC 5 and air is drawn in together with the printed circuit board, as shown in Fig. 2 (a). When the flux attached to IC 1 reaches a high temperature and partially gasifies, air bubbles 9 remain on both sides of IC 50. This bubble 9
This impedes wetting of the molten solder 8 and reduces the reliability of soldering. Therefore, if the length L of the lead wire 6 is made longer than the size of the trapped air bubble 90 (reliability of soldering!), the mounting area of the IC 5 on the printed circuit board 1 will increase, and high-density mounting will be hindered. In addition,
Since the solder fillet 10 formed by the solder depth in the area where there is no resist film 4 is small, there are problems such as weak soldering strength.

Furthermore, when the printed circuit board 1 and the IC 5 are filled with molten solder 8 in the jet solder tank, the printed circuit board 1 moves in the direction of arrow A as shown in FIG. 2(b), and the molten solder 8
By flowing in the direction of arrow B, many bubbles S stay behind the IC 5 for the same reason as described above. In addition, IC5
It is difficult for the air bubbles 9 to stay in front of the area (and even if the air bubbles 9 do stay there, they are small).

Therefore, in particular, the lead wire 6 in the rear part is
There is a problem similar to that in case a).

[Purpose of the invention]

This invention was made in view of the above points, and it improves soldering reliability and soldering strength, reduces the mounting area of circuit components on a printed circuit board, and enables daytime density mounting of circuits. The present invention provides a method for soldering parts.

[Summary of the invention]

In order to achieve the above object, the present invention provides a circuit component soldering method in which a circuit component having a plurality of lead wires is soldered to a predetermined wiring pattern on a patterned surface of a printed circuit board by a solder dip method. Each of the lead wires has a horizontal portion that is substantially parallel to the printed circuit board, and a bent portion at the tip of this horizontal portion that is bent in a direction opposite to the direction in which the printed circuit board is located, so that the plurality of lead wires are Soldering is performed by placing the circuit components facing the predetermined wiring pattern using the solder dip method, improving soldering reliability and soldering strength, reducing the mounting area of the circuit components on the printed circuit board, and high-density mounting. This made it possible.

〔Example〕

FIG. 3 is a cross-sectional view showing an embodiment of the present invention, in which the plurality of lead wires 6 have a horizontal portion 6a that is substantially parallel to the printed circuit board 1 and extends in a substantially horizontal direction, and a tip of this horizontal portion 6a that is connected to the printed circuit board. It consists of a bent part 6b that is bent in the opposite direction to the direction in which the part 1 is located. Note that other symbols indicate the same parts as in FIG.

In the case of this invention, for example, when the IC5Y printed circuit board 1 is held upright in the hole 2, the predetermined wiring pattern 3 and the horizontal portions 6a of the plurality of lead wires 6 face each other, and the bent portions 6b are on the side opposite to the printed circuit board 1. Since it will protrude to
Even if air bubbles 9 remain on both sides or behind the IC 5 when the IC 5 is soldered into the molten solder 8 as shown in a) and (b), the bent portion 6b will come into contact with the molten solder 8.
, this weakens the surface tension of the molten solder 8,
In particular, the outside of the bent portion 6b is wetted by the molten solder 8. Therefore, the solder fillet 10 is sufficiently formed as shown in FIG. 3, and the soldering reliability and soldering strength are improved. In addition, since the bent portion 6b promotes wetting of the molten solder 8, soldering becomes more efficient and the length of the horizontal portion 6a of the lead wire 6 is shortened (as a result, the mounting area to the printed circuit board 1 is reduced). , high-density mounting is possible.Furthermore, when replacing the IC5, the solder fillet 10 can be melted and the bent portion 6bY can be pinched with a tool such as a bottle set, making it easy to separate the wiring pattern 3 and the lead wire 6. , IC5
can be easily replaced.

FIG. 4 is a sectional view showing another embodiment of the present invention, in which the IC5
The plurality of lead wires 6 consist of a horizontal portion 6a which is led out from the lower surface of the IC 5 and immediately bent in a substantially horizontal direction, and a bent portion 6b which is formed by further bending the tip portion of the horizontal portion 6a. and,
Turn this IC5Y upside down and glue a plurality of pieces of adhesive 7 to the butter/side of the printed circuit board 1 [6 and the predetermined wiring pattern 3].
are attached so that they are facing each other. Note that other symbols indicate the same parts as in FIG.

In the case of this embodiment as well, the solder depth is similar to that of the embodiment shown in FIG. 3, and the solder fillet 10 is sufficiently formed to produce the same effect.

〔Effect of the invention〕

As explained above, since the circuit component of the present invention is soldered to a printed circuit board using a solder dip, a sufficient solder fillet is formed, improving soldering reliability and soldering strength. Since the wetting of the molten solder can be promoted by the paper part of the lead wire in the housing, the length of the lead wire can be shortened. Mounting is possible.Also, there are advantages such as easy replacement of circuit parts due to the bent portion of the lead wire.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of circuit components soldered using a conventional soldering method, Figures 2 (a) and (b) are illustrations of solder depths, and Figure 3 is a cross-sectional view showing one embodiment of the present invention. , FIG. 4 is a sectional view showing another embodiment of the present invention. In the figure, 1 is a printed circuit board, 2 is a hole, 3 is a wiring pattern,
4 is a resist film, 5 is an IC, 6 is a lead wire, 6a is a horizontal portion, 6b is a bent portion, T is an adhesive, 8 is a molten solder, 9 is a bubble, and 10 is a solder fillet. Figure 1

Claims (1)

[Claims] Multiple leads, @′? : A circuit component soldering method in which a circuit component having a lead wire is soldered to a predetermined wiring pattern on a patterned surface of a printed circuit board by a solder dip method, wherein each of the plurality of lead wires has a horizontal portion substantially parallel to the printed circuit board; The horizontal portion has a bent portion bent in the opposite direction to the direction in which the printed circuit board is located, and the plurality of lead wires are placed opposite to the predetermined wiring pattern and soldered using a solder dip method. A method for soldering circuit components, characterized by: