JPS6348893A - Lead terminal soldering - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] In the soldering of lead terminals of electronic components to a printed wiring board, the present invention applies soldering such as solder cream or pre-solder + solder layer to a part of each soldering surface. By forming and soldering only in the area, short circuits between lead terminals due to excess solder flowing out can be prevented.

[Industrial application field]

The present invention relates to a method for soldering lead terminals of electronic components to a printed wiring board, and particularly to a method for soldering lead terminals using preliminary solder or solder cream.

For attaching electronic components to printed wiring boards, immersion soldering (a method in which the joint surface is immersed in a bath of molten solder for soldering), reflow soldering (remelting method: pre-soldering or plating, etc.) have been used for a long time. Solder cream printing method (a method in which a solder layer prepared in advance on the joint surface is melted using hot air, etc.), a solder cream printing method (a method in which a cream made by mixing powdered solder and flux is printed on the joint surface in advance) Soldering methods such as a method of melting and soldering using hot air or the like are widely used.

On the other hand, with the increase in the number of lead terminals in electronic components such as circuits and connectors and the high-density mounting of printed wiring boards, the spacing between the lead terminals of electronic components has become extremely narrow.

For this reason, when soldering the lead terminals of electronic components to a printed wiring board, be careful not to cause a short circuit between the lead terminals due to excess solder.

It is necessary to distribute enough haste.

[Conventional technique 1/Fr] Figure 4 ((a) front view, (b) sectional view) is an explanatory diagram of a conventional example, where 3 is an electronic component, 31 is a lead terminal of the electronic component 3, and 4 is a printed wiring. board, 41 is the lead wire terminal 31 (l
The solder area (also referred to as a pad land) on the printed wiring board 4 side provided corresponding to the soldering surface of ul+, and 5' represent solder cream.

That is, in the conventional example, solder cream 5' is applied by printing to the entire surface of each soldering surface 41 on printed wiring board 4, and solder cream 5' is applied with hot air while the lead terminals 31 of electronic component 3 are pressed onto the solder cream 5'. (By doing so, the solder in the solder cream 5' was melted and the joint was made.

[Problem that the invention seeks to solve]

In the conventional example described above, electronic:) 3 products 3 leads/terminals 31
In the case where the distance between the soldering surfaces 41 and the lead terminals 31 is narrow, a solder bridge formed by the excess solder causes a short circuit between adjacent soldering surfaces 41 or lead terminals 31.

There was a problem that product defects occurred.

That is, an object of the present invention is to prevent the occurrence of solder bridges.

[Means for solving problems]

A method for soldering lead terminals according to the present invention.

As shown in the principle diagram in Figure 1.

Each soldering surface of the lead terminal of electronic components or each soldering surface on the corresponding printed wiring board.

A material layer forming step 1 in which a soldering material layer is formed only on a partial area of each soldering surface on at least one side.

The printed wiring board and the lead terminal are bonded by a heating step 2 of heating the printed wiring board, on which at least one of the soldering material layers is formed, and the lead terminal while being pressed against each other.

[Effect]

As shown in FIG. 2 ((a) front view/(bl sectional view)).

By forming the solder + solder material 5 only in a part of the area sandwiched between the soldering area of the lead wire terminal 31 and the soldering surface 41 on the printed wiring board 4 instead of the entire area, excess solder can be removed. It is possible to prevent the occurrence of solder bridges due to the outflow of solder.

〔Example〕

The gist of the present invention will be specifically explained with reference to the sectional view shown in FIG.

The electronic component connected to the printed wiring board 4 is the connector 3'.
The lead terminals 31' are provided in two rows,
These are configured to be soldered to both sides of the printed wiring board 4.

To attach the lead terminals 31' to each solder pin 41 on the printed wiring board 4 side, connect the lead terminals 31' arranged in two rows along the surface of the printed wiring board 4.
Do this by inserting it in between.

For this reason, the tip of each lead terminal 31' is bent outward with respect to the surface of the printed wiring board 4.

Further, the solder cream 5' is formed by printing only at a location on each soldering surface 41 where it will not be pushed away by the tip of the lead terminal 31' during the insertion.

Length J approximately 5 mm - Width approximately 1, arranged at intervals of 0.1 mm
mm glued terminals 31' to the soldering surface 11 arranged on the printed wiring board 4 with the same width and spacing.

As a result of soldering using the above method, it was possible to significantly reduce the occurrence of solder bridges compared to the conventional example.

〔Effect of the invention〕

As explained above, the lead terminal soldering method according to the present invention can prevent product defects due to poor soldering, and has the effect of reducing costs.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle of the present invention. Fig. 2(al) and (b) are explanatory diagrams of the action. Fig. 3 are explanatory diagrams of the embodiment. Fig. 4 fa) and (b) are explanatory diagrams of the conventional example. In the figure. 1 is a material layer forming process, and 2 is a heating process. 3 is an electronic component, 31 and 31' are beam terminals. 4 represents a printed wiring board 5; 5 represents a solder material layer 25'; a solder cream;

Claims (2)

[Claims] (1) A method for soldering lead terminals of electronic components to a printed wiring board, the method comprising: each soldering surface of the lead terminal or at least one of each soldering surface on the corresponding printed wiring board; a material layer forming step (1) of forming a soldering material layer only in a partial region of the printed wiring board and the lead terminal, the printed wiring board having the soldering material layer formed on at least one side thereof pressed against each other; A method for soldering lead terminals, which comprises joining a printed wiring board and lead terminals by step (2). (2) The method for soldering lead terminals according to claim (1), wherein the soldering material layer is formed by printing solder cream.