JPH034438Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a jet solder bath for soldering printed circuit boards, particularly printed circuit boards mounted with chip components.

Conventionally, there is a method of using a jet solder bath for soldering printed circuit boards. In this method, printed circuit boards are soldered by being immersed in a jet of molten solder.During the immersion, rough waves are applied to the jet of molten solder, causing the solder to penetrate into the corners of the chip components. Soldering defects can be eliminated.

Regarding the structure of jet solder baths used for soldering printed circuit boards mounted with chip components, many structures with wave-making devices have been proposed, but all of them are equipped with members that slide or rotate within the molten solder bath. Because of this, there are many failures, and the driving device for such wave-making devices must be installed separately outside the tank, making them very expensive. Moreover, in these cases, the jet of molten solder was uneven and the ripples were insufficient, making it impossible to achieve high-quality soldering.

The applicant of the present invention has studied a jet solder bath that can easily and inexpensively give rough waves to a jet of molten solder, and has supported both ends of a floating body installed through the side plate of the nozzle of the jet solder bath with tension springs. proposed a jet soldering bath (Patent Application No. 100591/1983).

The jet solder bath has a structure in which the floating body is supported by a tension spring from the outside of the side plate, and since the tension spring is not immersed in the molten solder, the jet solder tank has already been proposed by the applicant of the present invention in Utility Application No. 193624/1983. This has the advantage that the life of the spring is longer than that of a solder bath (in which the tension spring supporting the floating body is in the molten solder bath).

[The problem that the idea attempts to solve]

However, in jet solder baths in which the springs supporting the floating bodies are installed outside the side plates, after long periods of use, the movement of the floating bodies sometimes changes and the waves no longer form the desired shape.

The object of the present invention is to provide a jet solder bath that can always produce a predetermined wave even after long-term use.

[Means to solve the problem]

The present inventors investigated the causes of wave changes in a jet soldering bath in which a conventional tension spring was installed outside the side plate of the nozzle, and found that the hole 3 drilled in the side plate 2 and the floating body as shown in Figure 4. It was found that this was because the molten solder flowing out from the gap 4 was applied to the tension spring 12. In other words, when molten solder is applied to a tension spring, it remains inside the tension spring, but the molten solder becomes small particles due to surface tension, and since the temperature is high, it is easily oxidized.
It adheres in the form of an oxide between the spiral turns of a tension spring.
If solder oxide adheres between the spiral turns of the tension spring, the distance between the spiral turns becomes wider and the restoring force becomes weaker.
As a result, the movement of the floating body becomes slow and the wave shape of the jetting molten solder changes. Therefore, the inventors of the present invention proposed that in a jet soldering bath with a structure in which floating bodies are supported by tension springs, if molten solder is prevented from touching the tension springs, oxides will not adhere to the tension springs, and the restoring force of the tension springs will be reduced. This invention was completed with a focus on not weakening it.

The present invention includes a nozzle for spouting molten solder consisting of a pair of spaced-apart nozzle plates and side plates standing upright on both sides of the nozzle plates, and both ends of a floating body installed passing through the side plates are connected by tension springs. This jet solder tank is characterized in that a solder blocking plate is installed on the floating body that penetrates the side plate and projects to the outside of the nozzle in the supported jet solder tank.

〔Example〕

Fig. 1 is a perspective view of a nozzle installed in a jet soldering bath according to the present invention, and Fig. 2 is a front center sectional view of the same.
It is composed of side plates 2, 2, which are erected to face each other at both ends thereof. Hole 3 at the top of each side plate
A floating body 4, whose both ends project slightly outward from the side plate, is inserted through the hole.
The hole 3 is sufficiently larger than the floating body 4. A spring engaging portion 5 and a male screw 6 are formed at both ends of the floating body 4, and a solder blocking plate 7 having a diameter larger than the hole 3 of the side plate is screwed into the male screw. The mounting position of the solder blocking plate should be a little spaced apart from the side plate 2 so that it does not come into contact with the side plate 2. A U-shaped box 8 is installed outside the nozzle with the hole 3 in the side plate as the center. A hole is bored in the end face of the box, and a bolt 10 having a spring engaging portion 9 at its end is easily inserted into and removed from the hole. The bolt on the outside of box 8 has a length adjustment nut 11.
are screwed together. A tension spring 12 is attached to the spring engaging portion 5 of the floating body 4 and the spring engaging portion 9 of the bolt 10.
is installed.

Next, the flowing state of solder in the jet solder bath of the present invention having the above structure will be explained.

Molten solder sent by a pump (not shown) is blown up at the nozzle. At this time, the vigorous molten solder hits the floating body 4 installed in the nozzle, but since the floating body is supported by tension springs 12 at both ends, it moves irregularly. This irregular movement of the floating body disturbs the waves of the solder jet and allows the molten solder to easily penetrate into the corners of the chip mounted on the printed circuit board.

By the way, in the jet soldering bath of the present invention, the solder blocking plate 7 is installed on the floating body protruding outward from the nozzle of the side plate, so as shown in FIG. The molten solder flowing out is blocked by the solder blocking plate and does not reach the tension spring.

[Effect of idea]

In the jet soldering bath of the present invention, the molten solder flowing out from the gap between the hole in the side plate and the floating body does not touch the tension spring that supports the floating body, so no solder oxide adheres to the tension spring, and the tension spring It does not weaken its resilience.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a nozzle installed in a jet solder bath according to the present invention, FIG. FIG. 4 is a diagram illustrating the flow state of molten solder in a conventional jet solder bath. 1... Nozzle plate, 2... Side plate, 3... Hole, 4...
...Floating body, 7... Solder blocking plate, 12... Tension spring.

Claims (1)

[Scope of utility model registration request] A jet solder that includes a nozzle for spouting molten solder consisting of a pair of spaced and opposing nozzle plates and side plates set up on both sides of the nozzle plates, and in which both ends of a floating body installed through the side plates are supported by tension springs. A jet soldering tank characterized in that a solder blocking plate is installed on a floating body that penetrates a side plate and projects to the outside of a nozzle in the tank.