JPS6023099Y2 - static solder bath - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a soldering bath for soldering, particularly a deep static bath.

The most rational and reliable method for soldering a large number of components mounted on a printed circuit board at once is to immerse the printed circuit board and component leads in a solder bath.

Solder baths used in immersion soldering generally include jet solder baths and static solder baths.

The former type of jet soldering bath has a pump installed at the bottom of the bath.
The pump jets the molten solder vigorously from a horizontally long nozzle, and the printed circuit board is brought into contact with the top of the jet as it advances, thereby sequentially soldering the solder.

However, soldering a board using a jet flow may cause defects such as mounted components being moved by the molten solder having a high specific gravity or being pulled out.

In addition, in the jet type, since molten solder is jetted, it is very easily oxidized, and the expensive solder becomes oxide and decreases, resulting in a large economic loss.

On the other hand, the latter type of static solder bath does not spray molten solder, so unlike the jet type, there is no accident of the mounted components coming off, and there is less oxidation of the solder, making it more reliable and economical. Better than jet type.

Therefore, in recent years, static solder baths have come to be widely used in S and COS method soldering (S: temporary soldering, C: lead cutting, S: actual soldering).

However, in a static solder bath, the molten solder does not flow in the bath like in a jet type, so the temperature distribution in the bath is not uniform, and the temperature at the temperature sensing point and the actual soldering point may differ. In some cases, soldering was not done at the correct temperature.

In other words, if the temperature sensor is installed in a location where the temperature is low, such as a corner of the bath, the temperature at the soldering location may become too high and the mounted components may be damaged due to heat effects. Also, if the temperature sensor is installed near a heater, the temperature at the soldering point will be low, causing icicles and bridges to form on the board, causing soldering defects.

Therefore, there has been a desire in this industry for a static bath that can perform soldering at an appropriate temperature.

The present invention eliminates the non-uniform temperature distribution in the static solder bath.

The features of the present invention are that, in a deep stationary solder bath, a partition wall with openings at both ends is provided at approximately half the depth of the solder bath to divide the solder bath into upper and lower parts;
A static solder bath is provided in which a flow device is installed in one opening to allow the solder on the upper and lower parts of the partition wall to flow in opposite directions.

The present invention will be explained below based on the drawings.

FIG. 1 is a plan view of the static solder bath of the present invention, and FIG. 2 is a sectional view taken along the line A--A in FIG.

A partition wall 2 that divides the bath into upper and lower parts is installed in the horizontal center of a deep stationary solder bath 1, and the partition wall 2 has openings 3 at both ends.
, 3'.

A flow device is installed in one opening 3'.

The flow device is a device that can flow the solder in the upper and lower parts of the partition wall 2 in opposite directions, respectively. In the embodiment shown in FIGS.
It is located close to.

A shaft 5 supporting the roller 4 extends to the outside of the stationary solder bath, and a large-diameter gear 6 is fitted to the tip of the shaft 5. Furthermore, the large-diameter gear 6 is connected to a small-diameter gear 8 fitted to a motor 7. It meshes with the.

9 is a heater that heats the solder; 10 is a heat sensitive part that senses the temperature of the solder in the bath and adjusts the supply of power to the heater 9; and 11 is a heat insulating material.

Next, the usage conditions of the static solder bath of the present invention having the above-mentioned configuration will be explained.

Fluidizer roller 4 installed in one opening 3' of partition wall 2
By the rotation of the motor 7 located outside the solder bath, the small diameter gear 8 and the large diameter gear 6 are sequentially driven and rotated slowly in the direction of the arrow in FIG. 2.

At this time, the molten solder near the roller flows slowly as the roller rotates, enters one opening 3', passes through the lower part of the bath where the heater is located, and exits to the other opening 3.

That is, the molten solder in the upper and lower portions separated by the partition wall 2 flows in opposite directions by rollers serving as flow devices.

The flow of this molten solder is caused by the slow rotation of the roller.
Further, as shown in the figure, since the opening 3 is relatively wide, the molten solder exiting the opening 3 does not spout out the solder liquid surface or form a liquid chamber at all.

Therefore, even though the solder liquid level is static, the inside of the bath is slowly flowing, and the solder heated by the heater,
The solder is heat-radiated and cooled uniformly on the surface and bath wall surface, resulting in a uniform temperature distribution.

FIG. 3 is a plan view showing another embodiment of the present invention, and FIG. 4 is a sectional view taken along the line B--B in FIG. 3, in which a propeller 12 is used as a flow device for flowing molten solder.

(The drive device is not shown) The opening 3' in which the propeller 12 is installed has a diameter slightly larger than the propeller diameter.
The propeller is rotated slowly enough to prevent the solder liquid level from becoming a liquid chamber.

The slow rotation of the propeller can cause the solder on the upper and lower parts of the partition wall 2 to flow in opposite directions.

As explained above, in the stationary solder bath of the present invention, since the molten solder flows slowly inside the solder bath, a uniform temperature distribution is obtained, and accidents such as poor soldering and damage to mounted components are completely eliminated. It is something that can be done.

[Brief explanation of drawings]

Figure 1 is a plan view of the proposed stationary solder bath, Figure 2 is Figure 1A
-A sectional view, FIG. 3 is a plan view showing another embodiment of the static solder bath of the present invention, and FIG. 4 is a sectional view taken along the line B--B in FIG. 3. 1... Solder bath, 2... Partition wall, 3,3
′, song, opening, 4... Ta-ra, 12...
propeller.

Claims (1)

[Scope of utility model registration request] In a deep stationary solder bath, a partition wall with openings at both ends is provided at approximately half the depth of the solder bath to make the solder bath into upper and lower parts, and one opening is used to connect the upper and lower parts of the partition wall. A static solder bath characterized by being equipped with a flow device that can flow a certain solder in the opposite direction.