JPS6031005Y2 - solder bath - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a solder bath in which a printed circuit board is immersed in a solution solder flow for soldering.

Conventionally, this type of solder tank is equipped with a heater and an impeller, and the impeller causes the solder melt in the solder tank body to flow continuously from one end to the other, keeping the surface of the solder melt constantly clean. I try to keep it that way.

However, the flow surface of the solder melt is worse in the part where it flows in contact with the side wall of the solder bath body than in the center part due to fluid friction with the side wall, which has the disadvantage that oxides and solder particles tend to accumulate. Ta.

This idea was made to eliminate the above-mentioned drawbacks. A pair of endless chains are rotated on both side walls of the solder bath body to improve the flow of the solder melt on the side walls and prevent oxides from forming. The solder scum is allowed to flow downstream.

This invention will be explained below based on the drawings.

Figure 1 is a plan view showing an embodiment of this invention, Figure 2 is a sectional view taken along line A-A in Figure 1, and Figure 3 is B-B in Figure 1.
FIG. 4 is a cross-sectional view taken along line C--C in FIG. 1.

In these figures, reference numeral 1 denotes a main body of an immersion type solder bath, the side walls and bottom of which are surrounded by a heat insulating material.

2 is a solder melt melted to a predetermined temperature; 3 is a sheathed heater for keeping the temperature of the solder melt 2 uniform and constant; 4 is an impeller for forcibly circulating the solder melt 2; It is rotated in a fixed direction by a drive device such as a motor.

Reference numeral 5 denotes a partition plate that divides the solder melt 2 into upper and lower parts in the solder tank body 1, and is provided in the horizontal direction.

6 is an outlet provided at one end of the partition plate 5; 7 is a weir plate provided on the downstream side of the solder melt 2;
This is to keep the liquid flow surface horizontal.

Reference numeral 8 denotes a partition tube provided on the side of the partition plate 5 on the downstream side of the solder melt 2, and 9 is a reflux port provided at the lower end of the partition tube 8.

Note that the impeller 4 is installed above the reflux port 9 in order to reflux the solder melt 2 upward and downward.

Reference numeral 10 indicates a conduction port through which the solder melt 2 in the partition tube 8 flows out to the lower part of the partition plate 5, 11 a side plate provided on the side of the weir plate 7, and 12 provided on the downstream side of the weir plate 7. One drive shaft is supported by the solder tank main body 1 and the other by the side plate 11.

13 is a driven shaft provided on the upper part of the partition plate 5 on the side of the outlet 6 of the solder melt 2 at the same level as the drive shaft 12; 14 is a sprocket that rotates in conjunction with the drive shaft 12 and the driven shaft 13; Both sprockets 14 are provided facing each other in the vicinity of both side walls of the solder tank body 1, and each sprocket 14 is connected by a pair of endless chains 15.

16 is a drive sprocket provided on an extension of the drive shaft 12, and 17 is a drive device such as a motor.

In this way, the driving shaft 12, the driven shaft 13, the endless chain 1
5 are made of a material with a melting point higher than that of the solder and less susceptible to electrolytic corrosion, and are constantly immersed in the solder melt 2.

The pair of endless chains 15 are placed near both walls of the soldering surface of the solder tank body 1, and the surface side of the endless chains 15 is half immersed in the flow surface of the solder melt 2. It is driven in the same direction as the flow direction of the solder melt 2.

Next, the operation will be explained.

The solder melt 2 in the solder bath body 1 is maintained uniformly at a constant temperature by a sheathed heater 3.

When the impeller 4 rotates, the solder melt 2 in the partition tube 8 passes through the communication port 10 and advances below the partition plate 5 in the direction of arrow A in the figure, reaching the outlet 6.

Here, the solder melt 2 rises and moves in the direction of arrow B, changes direction, and the soldering above the partition plate 5 moves in the direction of arrow C, overflows from the weir plate 7 and passes under the side plate 11. and flows into the outer circumference of the partition tube 8.

The solder melt 2 around the partition tube 8 changes direction and flows into the partition tube 8 from the return port 9 as shown by the arrow.

In this way, the solder melt 2 is refluxed.

Next, the pair of endless chains 15 are driven by the drive device 17 and rotated by the rotation of the sprocket 16.
The surface side of the solder melt 2 moves in the direction in which the solder melt 2 flows, that is, in the same direction as the arrow C direction.

Therefore, as the endless chain 15 moves, the flow of the melted solder 2 on both side walls of the solder tank main body 1, which has poor flow, becomes almost the same as the flow of the melted solder 2 on the center part, and the solder melt 2 flows on both side walls. The oxides and solder chips are pulled by the endless chain 15 and flowed downstream without remaining on the surface of the solder melt 2, and overflow together with the solder melt 2 at the weir plate 7.

Note that the oxides and solder scum stay on the surface of the solder melt 2 on the side plate 11 and the flow is blocked, so the partition tube 8
It will not leak to the side.

As explained above, this invention is a solder bath in which the solder melt in the solder bath body is made to flow continuously from one end of the surface of the solder bath body to the other end using an impeller, in the flow direction of the solder bath body. On the other hand, an endless chain was provided on each side of the chain, and the surface side of the endless chain was made to move in the same direction as the flow direction of the solder melt, so that the solder melt on both sides was The flow of the solder melt improves, and the oxides and solder chips are entangled with the endless chain and are forcibly removed, or the endless chain acts synergistically with the flow of the solder melt so that it is pulled even if it is not entangled with the chain. Since this is promoted, oxides and solder scum generated in this area do not remain on the liquid surface.

Therefore, it is possible to always obtain a soldering surface free of oxides and solder scum as a flow surface of the solder melt, which has the advantage of allowing effective soldering processing to be performed.

[Brief explanation of the drawing]

Figure 1 is a plan view showing an embodiment of this invention, Figure 2 is a sectional view taken along line A-A in Figure 1, and Figure 3 is B-B in Figure 1.
FIG. 4 is a cross-sectional view taken along line C--C in FIG. 1. In the figure, 1 is the solder tank body, 2 is the solder melt, 3 is the sheathed heater, 4 is the impeller, 5 is the partition plate, 6 is the outlet, 7 is the weir plate, 8 is the partition tube, 9 is the return port, 10 is a communication port, 11 is a side plate, 12 is a drive shaft, 13 is a driven shaft, 14 is a sprocket, 15 is an endless chain, 16 is a drive sprocket, 1
7 is a drive device.

Claims (1)

[Scope of utility model registration request] In a solder tank that includes an impeller in the solder tank body and causes the solder melt to flow continuously from one end of the inner surface of the solder tank body to the other end by the impeller, the solder melt in the solder tank main body is A solder bath characterized in that endless chains are provided on both sides of the solder bath, the surface side of which runs in the same direction as the flow direction.