JPH04197576A - Soldering method - Google Patents

Abstract

PURPOSE:To execute the soldering work with high characteristics by preheating soldering part, dipping into a flux vessel and dipping into a soldering vessel in successively plural times. CONSTITUTION:The soldering part in a product having a substrate 1, soldering lands 1a and terminals 4 is dipped into solder 10 in the soldering vessel 9. Then, the soldering part is preheated at the prescribed temp. After preheating, this soldering part 1, 1a, 4 is dipped into flux 8 in the flux vessel 7 in successively two times. After dipping into flux, the soldering part 1, 1a, 4 is dipped into the solder 10 in the soldering vessel 9 in successively two times. By this method, activation of flux is sufficiently executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a soldering method in which a soldered portion of a product is immersed in a solder bath to perform soldering.

[Conventional technology]

Conventionally, when performing immersion soldering, in order to obtain good soldering characteristics, before immersing the soldered part of the product in a soldering bath,
The soldered portion is immersed in a flux bath to form a flux layer, and then the soldered portion is heated, for example, at about 100° C. to activate the flux layer.

(Problems to be Solved by the Invention) In the conventional soldering method described above, after forming a flux layer on the soldered part of the product, the soldered part is preheated to activate the flux layer.

Flux may scatter during preheating and stick to equipment such as conveyors that transport products, staining the area around the equipment. If the stain caused by this flux is left untreated, it will cause problems in the operating mechanism of the equipment, so it is desirable to prevent the flux from scattering as much as possible.

In order to solve the above problem, for example, it is possible to preheat the soldered part of the product and then immerse it in a flux bath to form an activated flux layer. There is a drawback that part III is lowered and the flux cannot be activated sufficiently.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a soldering method that can activate flux without scattering the flux and perform soldering well.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a soldering method in which a soldered part of a product is immersed in a soldering bath for soldering, including a preheating step of heating the soldered part to a predetermined temperature in advance;
The method consists of a flux immersion step in which the soldered portion is immersed in a flux bath after preheating, and a solder immersion step in which the soldered portion is immersed in the solder bath twice in succession after being immersed in flux.

[Effect]

According to the method of the present invention, after preheating the soldered part of a product, the soldered part is immersed in a flux layer, so that flux is applied to the soldered part without scattering. In addition, when the soldered part on which a flux layer has been formed is immersed into the solder layer and then lifted into the air, the activation of the flux progresses due to the heating caused by immersion in the solder bath, and the decomposed gas is sufficiently released. , the flux is sufficiently activated. By immersing the soldered portion in the solder bath again, soldering can be performed appropriately.

〔Example〕

The soldering method according to the present invention will be explained using terminal soldering of a hybrid IC as an example.

FIG. 1 is a diagram showing a configuration when input/output terminals of a hybrid IC are soldered. In the figure, reference numeral 1 denotes a board of a hybrid IC, and electronic components (not shown) are soldered to both sides or one side. Soldering lands la (soldering portions) to which terminals 4 are soldered are provided at predetermined intervals on one long side of the board 1. Also, 2 is the guide plate 3
The terminal 4 is made of a hoop material in which a large number of terminals 4 are formed at predetermined intervals, and the tip of the terminal 4 is formed with a bifurcated clamping part (not shown). The board 1 is attached to the hoop material 2 with the end clamping portion of the terminal 4 being clamped at the position of the soldering land 1a. A plurality of substrates 1 are attached to this hoop material 2 at predetermined intervals.

Note that the terminals 4 that are not attached to the substrate 1 are thinned out. Reference numeral 5 denotes a support belt that supports the substrate 1 and is capable of transporting and raising and lowering the hoop material 2 and the substrate 1 as described later.
It supports the substrate 1 when the soldering land 1a portion is immersed in a flux layer or a solder layer.

The second procedure for soldering the terminals of the hybrid IC with the above configuration is as follows.
This will be explained using FIGS. 3(a) and 3(b).

Figure 2 is a partial front view showing the flux immersion process in which the solder-dipped part of the hybrid LC board shown in Figure 1 is dipped into a flux bath, and Figure 3 (a) is the solder-dipped part of the hybrid IC board. Figure 3 (b) is a partial front view showing the solder bath immersion process in which the hybrid IC is immersed in the solder bath.
FIG. 3 is a diagram showing a state in which the solder-immersed part of the solder is pulled up from the solder bath.

For convenience of explanation, a case will be described here in which a predetermined number of boards 1 are attached to the hoop material 2 (hereinafter, a set of boards 1 is referred to as a set board A), and terminal soldering is performed for each set.

First, the set substrate A is preheated by placing it in a temperature bath of approximately 100° C. or placing it on a heating plate.

Next, as shown in FIG. 2, only the hoop material 2 and the soldering land 1a of the set board A (hereinafter referred to as the solder immersed area 6) are immersed in a flux bath 7, and the flux 8 is applied to the solder immersed area 6. be done. In this case, even though the flux 8 may be scattered, since the flux 8 is inside the flux tank 7, the outer periphery thereof will not be contaminated.

Next, the solder immersion portion 6 of the set board A is immersed in the solder bath 9 for a required time (FIG. 3(a)), and then lifted into the air (FIG. 3(b)). This immersion time is mainly for heating to activate the flux 8 in the solder immersion portion 6, and is set to an appropriate time depending on the set temperature of the solder bath 9. The flux 8 in the solder immersion section 6 is activated by this heating, and the generated decomposed gas is released into the air when it is pulled up into the air. Next, the solder immersion part 6 is immersed in the solder bath 9 again for a predetermined time (FIG. 3(a)), and then lifted into the air (
As shown in FIG. 3(b), the molten solder 10 in the solder immersion portion 6 is cooled and solidified. Since the flux 8 in the solder immersion part 6 is sufficiently activated, the molten solder 10 blends into the terminal 4 and the soldering land 1a to form a suitable alloy layer, and has good soldering characteristics due to cold solidification. Soldering is performed.

In the above embodiment, a case where a set of a predetermined number of boards 1 is soldered is explained. It is also possible to solder the terminals of the board 1 while performing each process.

Furthermore, the present invention is applicable not only to hybrid ICs but also to soldering work for various other circuit boards.

〔Effect of the invention〕

As explained above, according to the present invention, after preheating the soldered part of the product, the soldered part is immersed in the flux bath, so that the flux does not scatter and contaminate the surroundings of the equipment. It disappears.

Moreover, since the soldered portion is dipped twice in the solder bath after applying the flux, the flux is sufficiently activated by the first immersion in the solder bath.

Soldering work with good soldering characteristics can be performed.

[Brief explanation of the drawing]

Fig. 1 is a partial front view showing the configuration when the input/output terminals are soldered to the hybrid IC board, and Fig. 2 shows a flux dipping step in which the solder dipped portion of the hybrid IC board is dipped into the flux layer. Partial front view, Figure 3 (a
) is a partial front view showing the solder dipping step of dipping the solder dipping part of the hybrid IC board into the solder layer, and FIG.
) is a diagram showing a state in which the solder-immersed part of the hybrid IC board is pulled up from the solder bath. 1... Board, 1a... Soldering land, 2... Hoop material. 3... Guide plate, 4... Terminal, 5... Support band, 6
...Solder immersion part, 7...Flux tank, 8...Flux, 9...Solder tank, 10...Solder, A...
set board. Figure 1 Figure 2

Claims (1)

[Claims] 1. A soldering method in which a soldered part of a product is immersed in a soldering bath for soldering, includes a preheating step of heating the soldered part in advance to a predetermined temperature, and a flux immersion step of immersing the soldered part in a flux bath after preheating. and a solder immersion step of immersing the soldered portion in a solder tank twice in succession after being immersed in flux.