JP2000101226A - Soldering device and soldering method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent insufficient solder bonding by presoldering a part of the lead wire of a part mounted to a printed wiring board and removing a solder oxide floating on the surface of molten solder. SOLUTION: A mounting part 2 is mounted to a printed wiring board 1, and the lower surface of the printed wiring board 1 is kept close to the surface of molten solder 5 with a clearance g in between. Since the lower end of a part lead is dipped in the molten solder 5, the oxidized part on the surface of solder is melted by heat and it drops on the molten solder 5, and then a solder oxide 4 floats on the surface of the molten solder 5. Next, the printed wiring board is lifted up until the lower end of the part lead becomes apart from the surface of the molten solder 5. Then, the solder oxide 4 floating on the surface of the molten solder 5 is removed, and the surface thereof is cleaned. Further, the lower surface of the printed wiring board 1 and the part lead are dipped in the molten solder 5 again, so that a joint part containing no oxide is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stationary tank type soldering apparatus and a soldering method for soldering after mounting components on a printed wiring board.

[0002]

2. Description of the Related Art A static bath type soldering apparatus in which components are mounted on a printed wiring board and then soldered is characterized in that molten solder in a solder bath is hardly oxidized.

[0003]

However, the solder oxide previously coated on the lead wires of the components to be mounted on the printed wiring board floats on the surface of the molten solder in the solder bath, and the printed wiring board and the components are separated. There has been a problem that the soldering of the lead wires becomes insufficient and the reliability is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the reliability of the printed wiring board by solder oxide pre-coated on the component leads floating on the surface of the molten solder in the solder bath, resulting in insufficient solder bonding. It is an object of the present invention to provide a soldering apparatus and a soldering method that can prevent soldering.

[0005]

In order to achieve the above-mentioned object, before mounting a mounting component on a printed wiring board and performing soldering, pre-soldering is performed on a lead wire portion of the mounting component. Then, after removing the solder oxide floating on the surface of the molten solder, the printed wiring board and the lead wires of the mounted components are soldered.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIGS. 1 to 3 are side views showing a state in which components are mounted on a printed wiring board. FIG. 1 is an embodiment of the present invention and is a diagram for explaining the state of implementation of pre-soldering. 2 is an embodiment of the present invention and is a view for explaining the state of removal of solder oxide from the lead wire of the component by pre-soldering. FIG. 3 shows a conventional technique, in which the solder oxide of the lead wire is printed wiring board. FIG. 6 is a diagram for explaining a situation where the image has adhered to the image.

[0008] In the prior art, when the mounted component 2 mounted on the printed wiring board 1 is soldered by a static bath type soldering device, the solder previously coated on the component lead 3 is oxidized. When the component leads 3 and the printed wiring board 1 are immersed in the molten solder in the solder bath and pulled up in this state, as shown in FIG. Adhesion causes insufficient solder bonding and lowers reliability. This is because the oxidized solder previously coated on the component leads 3 floats on the surface of the molten solder when immersed in the molten solder in the solder bath, and the printed wiring board 1 and the component leads 3
This is because the oxide adheres to the solder joints when pulling up.

Therefore, in this embodiment, the printed wiring board 1
Before the soldering of the component leads 3, a pre-soldering process of the component leads 3 was added to solve the problems of the prior art.

In the pre-soldering step, as shown in FIG. 1, a printed wiring board 1 is mounted with a mounting component 2 in which component leads 3 are coated with solder in advance.
Are brought close to each other so as to maintain a gap g between the lower surface of the solder and the surface of the molten solder 5. Since the lower end of the component lead 3 is immersed in the molten solder 5, the oxidized portion of the surface of the solder coated on the component lead 3 is melted by heat and flows down to the molten solder 5, so that the solder oxide 4 is melted. It floats on the surface of the solder 5. The surface of the component lead 3 is covered with a non-oxidized surface from which oxide has been removed.

Next, as shown in FIG. 2, the printed wiring board 1 is raised until the lower ends of the component leads 3 are separated from the surface of the molten solder 5. Then, the solder oxide 4 floating on the surface of the molten solder 5 is removed by a solder oxide removing squeegee 6 provided in a solder melting tank 7 to clean the surface of the molten solder 5.

Next, the lower surface of the printed wiring board 1 and the component leads 3 are immersed again in the molten solder 5 so that a solder joint containing no oxide can be formed.

The solder oxide 4 floating on the surface of the molten solder 5 may be removed from the solder melting tank 7 by providing a jetting mechanism (not shown) in the tank 7.

As described above, in the static bath type soldering apparatus, since the printed wiring board and the mounted component can be soldered on the cleaned molten solder surface, the disadvantage that the lead wire of the mounted component is affected by the solder oxide is eliminated. Thus, highly reliable soldering can be obtained.

[0015]

As described above, according to the present invention, the solder oxide previously coated on the component lead wires of the printed wiring board floats on the surface of the molten solder in the solder bath, and the solder joint is formed. Insufficiency and reduction in reliability can be prevented.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention and showing a state where components are mounted on a printed wiring board.

FIG. 2 is a side view showing the embodiment of the present invention and showing a state where components are attached to a printed wiring board.

FIG. 3 is a side view showing the prior art, showing a state where components are attached to a printed wiring board.

[Explanation of symbols]

1: printed wiring board, 2: mounted component, 3: component lead,
4: solder oxide, 5: molten solder, 6: squeegee for removing solder oxide, 7: solder melting tank.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Zenshiro Oyama 1939, Tsuda-ji, Sekiba, Hitachinaka-shi, Ibaraki Prefecture Inside Naka Instruments Co., Ltd. F-term in the Hitachi Measuring Instruments Division (reference) 5E319 AA02 AB01 CC23 GG03

Claims (2)

[Claims] 1. A component lead of a mounted component is coated with solder in advance, and the mounted component is mounted on a printed wiring board.
In a soldering apparatus for immersing the component leads and the printed wiring board in molten solder for soldering, the component leads of the mounted components mounted on the printed wiring board are immersed in the molten solder and pulled up. A soldering device comprising a solder oxide removing means for removing the surface of molten solder. 2. A component lead of a mounted component is coated with solder in advance, and the mounted component is mounted on a printed wiring board.
In a soldering method in which the component leads and the printed wiring board are immersed in molten solder to perform soldering, the mounting component is placed on the printed wiring board, and the component leads are immersed in the molten solder and pulled up. A soldering method comprising: removing a surface of molten solder; and immersing the component lead and the printed wiring board in the molten solder to perform soldering.