JPH024791Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to an immersion type soldering device.

(Prior Art) Molten solder in a solder bath tends to have a high temperature at the center and a low temperature near the peripheral wall. The temperature is 250°C ± 10°C, but this 10°C temperature variation affects the soldering to the printed circuit board, and even on the same printed circuit board, there are parts that solder well and parts that do not.

To prevent such temperature variations,
There is a method that stirs molten solder using a stirring blade, as shown in Japanese Utility Model Publication No. 56-37910.

(Problems to be solved by the invention) However, the stirring blade shown in the above publication has a complicated structure with four blades attached to one shaft, which reduces the cost of the solder bath in manufacturing. There are some problems such as making it too expensive. Further, the stirring blades have to be structurally large, and the number of them that can be attached to the solder bath decreases accordingly, making it difficult to make the temperature of the surface layer of the molten solder truly uniform.

The purpose of the present invention is to make the temperature of the molten solder in the solder bath finely uniform over the entire surface.

[Structure of the idea]

(Means for Solving the Problems) The present invention provides a solder bath 3 equipped with removal spatulas 8 and 9 that move to remove solder oxide, etc., and a conveyance chain 6 that conveys the removal spatulas 8 and 9.
A stirring spatula 10 is provided for stirring the molten solder, and this stirring spatula 10 has a number of comb-like flat plate pieces 19 protruding from a spatula body 18, and each of the flat plate pieces 19 is twisted to make it inclined with respect to the direction of movement. It is something.

(Function) The present invention has a stirring spatula 1 along with removal spatulas 8 and 9.
0 is moved in the molten solder, and the molten solder is stirred with a stirring spatula 10 to make the solder temperature uniform over the entire surface layer. In that case, as the flat plate piece 19 that is twisted and inclined with respect to the traveling direction advances, the molten solder is moved laterally with respect to the traveling direction by the guidance of this flat plate piece 19, and each flat plate piece 19
Even during this period, the molten solder is effectively stirred.

(Examples) Hereinafter, the present invention will be described in detail with reference to examples shown in the drawings.

As shown in FIG. 1, a solder bath 3 is fixedly installed on a base 1 with a support 2 interposed therebetween. The lower part of this solder tank 3 is formed hollow, and both sides of the hollow part 4 are opened so that objects to be transported can be carried into the hollow part 4 and carried out from the hollow part 4. . 5 is a container for receiving oxides and the like.

An endless conveyor chain 6 extends from the upper side of the solder bath 3 to the lower side and surrounds the solder bath 3.
This conveyance chain 6 is supported by four rotatably supported sprockets 7.

As shown in FIG. 2, the conveyance chains 6 are provided in two rows on both sides of the solder bath 3, and two removal spatulas 8, 9 are installed in the two rows of conveyance chains 6 to remove solder oxide, etc. and one stirring spatula 10 for stirring the molten solder in the solder bath 3, and two sets of the same stirring spatula 10 are installed at two equal halves of the chain 6 on both sides.

The two rows of conveyor chains 6 share a common drive shaft 11.
is driven in the direction of the arrow in FIG. 2 by driving the motor 14 through the chain transmission mechanism 12 and reduction gear 13. Also, a limit switch 15 for stopping the motor 14 is arranged at the position where the spatulas 8, 9, 10 are taken out from the solder bath 3, and along the conveyance chain 6, the spatulas 8, 9, 10 are taken out from the solder bath 3. A guide (not shown) is provided to guide the spatulas 8, 9, 10 when moving under the solder bath 3.

The removal spatulas 8, 9 and the stirring spatula 10 are made of stainless steel or coated with tetrafluoroethylene (trade name: Teflon) to prevent solder from adhering to them. 9 and 10 are springless hinges 17 attached to a support bar 16 that spans between two rows of chains 6.
It is rotatably mounted. Also stirring spatula 10
is made up of a number of comb-like flat plate pieces 19 protruding from a spatula main body 18 having approximately the same height dimensions as the removal spatulas 8 and 9, and further, the flat plate pieces 19 are advanced by twisting the lower part by about 30 to 60 degrees. Tilt with respect to the direction. In addition, flat plate piece 1
9 is integrated by spot welding the upper part to the spatula body 18, but it may also be integrally formed by stamping from the spatula body 18.

Then, a holder holding a printed circuit board (not shown) immerses the printed circuit board on the surface of molten solder in the solder bath 3 while moving along a vertically moving rail (not shown), and operates the device every time it comes out of the solder bath 3. do. That is, when the cam attached to the camshaft of the drive cam of the vertical movement rail makes one rotation, one soldering operation is completed, but each time a limit switch (not shown) is activated and the motor 14 is rotated, the spatulas 8, 9, 10 moves in the direction of the arrow, operates the limit switch 15 at the position, stops the motor 14, and stops at that position.

When the spatulas 8, 9, and 10 move within the solder bath 3, the flat plate piece 19 of the stirring spatula 10 is inserted into the molten solder 20, as shown in FIG. Therefore, the molten solder 20 is stirred to make the solder temperature uniform over the entire surface layer of the solder bath 3. At the same time, the spatula main body 18 of the stirring spatula 10 and the tips of the removal spatulas 8 and 9 are inserted into the surface of the molten solder 20 to approximately the same depth, thereby scraping off solder oxide, etc. floating on the solder surface. Remove it by removing it. At this time, the remaining solder oxide and the like are removed by scraping with the spatula main body 18. At this time, the solder oxide and the like left behind by the spatula body 18 are scraped off by the removal spatula 9, and the solder oxide and the like left behind by the removal spatula 9 are scraped off by the removal spatula 8. This prevents oxides and the like from being left behind on the solder surface.

It is further preferable that the stirring spatula 10 is provided with floating prevention means so that it does not float due to the buoyancy of the solder or the like. That is, as shown in FIG. 4, protrusions 21 are formed on both sides of the upper part of the spatula main body 18 of the stirring spatula 10, and protrude in the opposite direction to the moving direction.
The spatula main body 18 is formed to be inclined so that it becomes horizontal when it is tilted by about 15 degrees, and stoppers 22 that come into contact when the protruding piece 21 becomes horizontal are installed parallel to each other on both sides of the solder bath. It goes without saying that the stopper 22 is provided at a position where it does not get in the way when soldering a printed circuit board (not shown).

When the stirring spatula 10 moves while stirring the surface layer of the molten solder 20, a force is exerted on the flat plate piece 19 to float on the solder liquid surface due to the buoyancy of the solder, but the spatula body 18 is tilted at an angle of about 15 degrees. when the protrusion 2
1 comes into contact with the stopper 22 and is prevented from tilting any further, thus effectively preventing the flat plate piece 19 from floating.

[Effect of idea]

According to the present invention, the entire surface of the solder bath can be stirred by the stirring spatula made of many flat plate pieces in a comb-like shape, and the temperature of the molten solder in the solder bath can be uniformly distributed over the entire surface layer of the solder bath. can be maintained.
In particular, since the flat plate pieces are twisted and tilted with respect to the direction of travel, as the flat plate pieces advance, the molten solder is guided by the flat plate pieces and moved laterally with respect to the direction of travel. The molten solder can be finely and effectively stirred even in between. Further, since the stirring spatula having a comb tooth shape has an extremely simple structure, it is easy to manufacture and can be made at low cost, and is advantageous in terms of maintenance.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view showing an embodiment of the soldering device of the present invention, Fig. 2 is a perspective view of its conveyance chain system, Fig. 3 is an enlarged front view of its main parts, and Fig. 4 FIG. 2 is an enlarged front view showing a modification of the main part thereof. 3... Solder bath, 6... Conveyance chain, 8, 9...
...Removal spatula, 10... Stirring spatula, 18... Spatula body, 19... Flat plate piece.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a solder bath equipped with a removing spatula that moves to remove solder oxides, etc., a stirring spatula for stirring molten solder is provided in a conveying chain that conveys the removing spatula, A soldering device characterized in that the stirring spatula has a number of comb-like flat plate pieces protruding from the spatula body, and each of the flat plate pieces is twisted so as to be inclined with respect to the direction of movement. (2) The soldering apparatus according to claim 1, wherein the stirring spatula is provided with floating prevention means for preventing the solder from floating due to buoyancy on its upper part.