JPS6343193B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a jet soldering method that provides a large amount of solder and excellent soldering strength.

In general, there are two types of soldering devices: dip type and jet type.The dip type allows for a large amount of solder and provides excellent soldering strength, but it also causes icicle-like solder drips and bridging. This method has disadvantages such as the generation of water, which can cause shot defects, and the need for a mechanism to move the solder bath itself up and down, which is disadvantageous in terms of equipment cost. The amount of solder adhesion was small, and the soldering strength was unstable.

As shown in FIG. 1, a conventional jet soldering device has an inner tank 2 housed within an outer tank 1, and a pump 3 disposed at the bottom of the inner tank 2. The solder 4 was jetted onto the upper surface of the inner tank 2, and the printed circuit board 7, which was held by a hanger 5 and had electronic components 6 incorporated therein, was passed through and soldered so as to be in contact with the upper surface of the jetted surface. .

However, the jet surface 4a of the solder 4 is flowing at a constant velocity, and the printed circuit board 7 is sent in the direction of arrow a in FIG.
When leaving the end of the jet, the adhering solder was scraped off by the flow velocity of the jet surface 4a, and as a result, the amount of solder was reduced as shown in FIG. In FIG. 2, reference numeral 8 indicates a lead terminal of the electronic component 6, and reference numeral 9 indicates solder attached to the lead terminal 8 and the land portion of the printed circuit board 7.

The present invention eliminates the drawbacks of the prior art as described above.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 5.

In FIGS. 3 and 4, 10 is an outer tank;
An inner tank 11 is formed within the outer tank 10, a communication hole 12 is provided in the lower part of the inner tank 11, and a pump 13 is arranged at the bottom of the inner tank 11.
This pump 13 is configured so that its output can be switched to two stages, and is configured to pump molten solder 14 into an inner tank 1.
1 to form a substantially flat jet surface 15, and the solder 14 overflowing from the inner tank 11 flows into the outer tank 1.
0 and is circulated again by the pump 13.

On the jet surface 15 of the solder 14, a printed circuit board 18 mounted with an electronic component 17 held by a hanger 16 and transported intermittently or continuously is located.

In soldering, first, as shown in FIG. 3, when the printed circuit board 18 is sent to a predetermined position, the output of the pump 13 increases and
The jet surface 15 of the printed circuit board 18 rises upward.
It operates so that it comes into contact with the bottom surface of the Printed circuit board 1
After the entire lower surface of 8 comes into contact with the jet surface 15, the pump 1 is activated by a signal that detects the position of the hanger 16.
Reduce the output of 3. In this way, as shown in FIG.
It will be below and away from the bottom surface of.

In this state, the printed circuit board 18 is sent in the direction of arrow A by the hanger 16 to complete the soldering work.

Note that the output of the pump 13 is reduced to reduce the solder 14.
The point at which the jet surface 15 is lowered is when the printed circuit board 18
This is carried out within the range where the entire lower surface of is in contact with the jet surface 15.

In addition, the amount of solder can be adjusted by changing the descending speed of the jet surface 15; increasing the descending speed will increase the amount of solder adhesion, and slowing down the descending speed will decrease the amount of solder adhering. can.

When soldering is performed using the jet soldering method described above, the solder 20 adheres to the lead terminals 19 of the electronic component 17 mounted on the printed circuit board 18 and the lands of the printed circuit board 18 in a spherical shape, as shown in FIG. This allows soldering to be performed with extremely high reliability in terms of soldering strength.

Since the jet type soldering method of the present invention is configured as described above, it is possible to increase the amount of solder even though it is a jet type, and it is possible to achieve excellent soldering strength.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing a conventional jet soldering device, Fig. 2 is a front view of the main parts of a printed circuit board soldered by the same device, and Fig. 3 is a cross-sectional view showing a conventional jet soldering device used in the jet soldering method of the present invention. 4th cross-sectional view showing the device
This figure is a sectional view showing another operating state of the device, and FIG. 5 is a front view of the main parts of a printed circuit board soldered according to the present invention. 10... Outer tank, 11... Inner tank, 12... Communication hole, 13... Pump, 14... Solder, 15... Jet surface, 16... Hanger, 17... Electronic component, 1
8...Printed circuit board, 19...Lead terminal, 20
……solder.

Claims (1)

[Claims] 1 A pump placed in the inner tank inside the outer tank jets molten solder from the top surface of the inner tank to form a jet surface, and after soldering a printed circuit board with electronic components mounted on this jet surface, A jet soldering method characterized by reducing the output of a pump to separate the jet surface from the printed circuit board.