JPS62209893A - Method of soldering and printed wiring board used for the soldering - 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 of the Invention] The present invention relates to a method for soldering leaded electronic components, and particularly to a method for soldering leaded electronic components by pre-soldering pads formed on a printed wiring board. The present invention relates to a method for soldering and a printed wiring board used for this soldering.

[Technical background of the invention and its problems]

Generally, circuit boards are mounted by temporarily mounting electronic components on a printed wiring board on which a predetermined pattern is formed using an automatic mounting machine, and then automatically soldering the electronic components by dip or flow soldering. However, for certain leaded electronic components such as electrolytic capacitors, the fifth
As shown in the figure, preliminary solder ■ is applied in advance to the electronic component mounting pad ■ of the printed wiring board ■ on which a predetermined pattern has been formed, and the electronic component (A) is applied to this preliminary solder ■ using an automatic or semi-automatic machine. This may also be done as a so-called post-installation process in which the leads (2) are brought into close contact with each other, the heater chip (0) is suppressed, and the preliminary solder (2) is heated and melted for soldering.

Also, it is white due to heater chip 0! Instead of protective or semi-automatic soldering, manual soldering may also be performed using a soldering iron.

However, pad (1) is usually formed into a rectangular shape having two long and short axes. Therefore, the preliminary solder (2) applied on this pad (2) is formed into a semicylindrical shape as shown in FIGS. On the other hand, the electronic components (A) are soldered to this pad ■.

Lead 0 is pressed against the preliminary solder surface so as to be aligned with the long axis direction of pad (2). Therefore, the lead (2) easily slips off the pre-soldered surface and is soldered off the pad (2), resulting in poor soldering.

[Purpose of the invention]

The present invention was made in order to solve the above problems, and aims to provide a soldering method and a printed wiring board that can easily prevent slippage caused by post-soldering of electronic components with leads. shall be.

[Summary of the invention]

This invention provides preliminary soldering to a leaded electronic component mounting pad formed on a printed wiring board and having at least two long and short axes, and when soldering the leaded electronic component to the pad, the long axis of the pad is By forming a solder resist film on the portion where the lead is to be attached before pre-soldering, the pad intersects the lead at a predetermined angle, thereby preventing misalignment of the lead with respect to the pad.

[Embodiments of the invention]

Hereinafter, the present invention will be described based on embodiments with reference to the drawings.

FIG. 1 shows a state in which leaded electronic components are soldered to pads formed on a printed wiring board, and FIGS. 2 to 4 show the soldering method.

The pad (11) of the printed wiring board (1 (1) shown in this example is formed into a rectangular shape with two long and short axes perpendicular to each other, and is attached to an electronic component with leads to be soldered). In this example, the long axis is formed to intersect the leads of the electrolytic capacitor at a predetermined angle.

To solder the electronic component (1) to this pad (11), first, as shown in FIG.
3), a solder resist film (14) having a width approximately equal to the diameter of the electronic component (1) is formed in a direction intersecting with the solder resist film (14) at an angle of 30''±15''. In this case, if the strip-shaped pad (11) is formed so that the long axis is 2 or more with respect to the short axis 1, the solder resist coating (1
4) can be formed in a preferable state such that it straddles the opposite long sides.

Next, as shown in FIG.
Preliminary solder (16) is applied to the pad (11) on which the pad (14) is formed.
). This preliminary solder (16) is applied to the pad (1).
It can be obtained by applying flux to 1) and then contacting it with reflow solder, for example. The solder adheres to the pad surfaces on both sides of the solder resist film (14), and a groove-shaped recess (17) is formed on the solder resist film (14) with one side surrounded by solder.

Next, as shown in FIG. 4, the solder resist coating (
14) in the recess (17), position the tip of the electronic component (a) glue 0 molded into a predetermined shape, and press the heater chip 0 onto the preliminary solder (16) to heat and melt it. , to the electronic components as shown in FIG.

Leads of electronic components (to) to be soldered as shown above (
For c), a pad (11) having two long and short axes is formed so that the long axes thereof intersect at a predetermined angle.

and forming a solder resist film (14) so as to intersect the long axis at a predetermined angle and applying preliminary solder (16);
When soldering is carried out along this solder resist film (14), the preliminary solder (1
6), and solder resist coating (1) across the ridge.
Since it can be positioned in the groove-shaped recess (17) obtained by forming 4), the leaded electronic component (A) will not be misaligned due to slipping from the preliminary solder as in the conventional case. It can be soldered to the pad (11).

In addition, in this soldering, the pad (11), which has two long and short axes, is connected so that its long axis is 30''±1 with respect to the lead ■.
When formed so that they intersect at an angle of 5', and the long axis is at least twice as long as the short axis,
The lead (2) can be placed so as to straddle the long side of the pad (11), and the soldering area can be increased to achieve highly reliable soldering.

In addition, if the pads (11) are formed in advance at a predetermined angle with the leads (c) to be soldered to the printed wiring board (IO), the mounting angle of the electronic component (■) with respect to the printed wiring board (IO) can be adjusted. It has the advantage that it can be installed without any special modifications.

In the embodiment described in "U", the pad is formed into a rectangular shape, but the pad may have any other shape as long as it has at least two long and short axes.

Furthermore, in the above embodiment, the pads were formed in advance on the printed wiring board so as to form a predetermined angle with the leads to be soldered. It can also be obtained by arranging the leads of electronic components so as to intersect the long axes of the pads at a predetermined angle on a printed wiring board that does not have a flat surface.

Furthermore, although the above embodiment describes an example of soldering an electrolytic capacitor, the present invention can also be applied to soldering multi-terminal electronic components such as flat package ICs and other electronic components with leads.

〔Effect of the invention〕

Before pre-soldering a pad formed on a printed wiring board and having at least two long and short axes, a solder resist film that intersects the long axis at a predetermined angle is formed, and after pre-soldering, this solder resist film is Since the leads of the electronic components are arranged and soldered along the ridges of the pre-solder to which the leads are attached in a semi-cylindrical shape, the leads are placed in the groove-like recesses formed in the solder resist film. Soldering can be easily performed without positioning and positional deviation.

Furthermore, if pads forming a predetermined angle with the leads are formed on the printed wiring board in advance, the electronic components can be mounted without changing the mounting angle of the electronic components.

[Brief explanation of drawings]

Figures 1 (A) to 1C) each show a state in which electronic components with leads are soldered to pads formed on a printed wiring board. Figure 1 (A) is a plan view, and CB) is a partial view. Front view shown in Figure (C) is I-I in Figure (A)
The line sectional view, FIGS. 2(A) and 2(I3) are explanatory diagrams of the pad and the process of forming a solder resist film on the pad, respectively, (A) is a plan view, and (B) is (A). The cross-sectional view taken along the line ■-■ in the figure, and Figures 3 (A) and (B) are explanatory diagrams of the process of applying preliminary soldering. Figure 4 is a partial cross-sectional front view for explaining the process of soldering electronic components with leads, and Figures 5 (A) to C) are respectively sectional views of conventional leaded electronic components. These are explanatory diagrams for soldering electronic components. (A) is a plan view, (B) is a front view, (
C) The figure is a side view. (1)...Electronic parts ■...Lead (1(1)
)...Printed wiring board (11)...Pad (14)
・・・Solder resist film (16) ・・・Preliminary solder agent Patent attorney Inoue - Male Figure 1 Figure 5

Claims (3)

[Claims] (1) Preliminary soldering is applied to a leaded electronic component mounting pad formed on a printed wiring board that has at least two long and short axes, and the leads of the electronic component are brought into close contact with the preliminary solder, and the preliminary solder is heated and melted. In the soldering method of soldering the above-mentioned electronic components, before pre-soldering the above-mentioned pads, a linear solder resist film intersecting the above-mentioned long axis at a predetermined angle is formed on the above-mentioned pads, and the above-mentioned pads are pre-soldered. A soldering method characterized in that the leads of the electronic component are arranged and soldered along the linear solder resist film. (2) The soldering method according to claim 1, characterized in that a linear solder resist film is formed in a direction intersecting the long axis of the pad at an angle of 30°±15°. (3) Printing that has a leaded electronic component mounting pad with at least two long and short axes, and the lead of the leaded electronic component is soldered to the pad by heating and melting preliminary solder applied to this pad. A printed wiring board, wherein the pad is formed in a direction in which the long axis intersects the lead of the leaded electronic component at a predetermined angle.