JPH0386372A - Soldering apparatus - Google Patents

Abstract

PURPOSE:To easily execute soldering of a lead terminal without causing short circuit by inserting the lead terminal as an electronic part into a pipe body at the roof part of a molten solder-contained vessel from the upper part, pushing a pressing member in the vessel, ascending the molten solder surface level and dipping the lead terminal therein. CONSTITUTION:At a part of the roof plate of the solder vessel 1 containing the molten solder 9, a molten solder lifting pipe 2 having an opening part at the upper part thereof is fitted and the lead wire 4 of the electronic parts 3 is hung down from the opening part and fixed. Successively, the molten solder 9 is heated by a heater 6, and the pressing member 8 is pushed into the molten solder 9 through a shifting and fixing mechanism 7, and by leveling down the molten solder surface, the lead wire 4 is dipped therein to execute the soldering. By this method, the soldering is easily executed with a compact apparatus without causing short circuit to the lead wire 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a soldering device for mounting and soldering electronic components on a printed circuit board.

[Prior Art] A printed circuit board has a printed circuit formed with a conductor such as copper, silver, or nickel on at least one surface of an insulating substrate such as a glass epoxy substrate or a ceramic substrate, and is used for resistors, capacitors, etc. The structure is such that through holes for inserting lead wires of these electronic components are formed in advance at positions where electronic components such as inductors are mounted.

To mount an electronic component on such a circuit board, first, the lead wire of the electronic component is inserted into a through hole of the circuit board, and the lead wire is led out to the back surface of the board.

Meanwhile, prepare a solder bath. A solder tank is a tank that melts and holds solder in the tank, and there are two types: a static tank that simply holds molten solder, and a static tank that only holds the molten solder, and a tank that holds the molten solder partially on the surface. There is a jetted solder jet tank. When a solder jet tank is used, the molten solder is maintained in a jet state, and the board is moved over the tank so that the surface of the board from which the lead wires are drawn comes into contact with the jet of solder. Solder the wiring conductor on the board.

As a result, the electronic components mounted on the board are soldered.

In recent years, there has been an increasing demand for miniaturization of electronic devices, and there is a tendency for miniaturized electronic components to be mounted at high density on printed circuit boards and the like. That is, if electronic components are to be mounted at a high density, the electronic components themselves must be made smaller, and their lead pitches also become narrower. Then, such small electronic components are placed close to each other on a printed circuit board,
High-density onboard electronic equipment is being created.

Using a conventional soldering device as described above, multiple lead terminals of electronic components placed on a board are simultaneously dipped into molten solder,
If soldering is attempted at the same time, solder often forms bridges between adjacent lead terminals or between lead terminals and conductor circuits, resulting in short circuits. Therefore, when soldering such microstructured parts, instead of simply passing the soldering device through the soldering device once, soldering is done partially using a thin soldering iron to avoid short circuits. This is the actual situation. On the other hand, if the electronic component body is immersed in a molten solder bath, the electronic component will receive a sudden thermal shock, which may cause a failure. Therefore, in the method using conventional soldering equipment, soldering of electronic components mounted on a board is done using a soldering iron to avoid short circuits in microstructures and sudden thermal shock to electronic components mounted on the board. There were times when it had to be done.

[Problems to be Solved by the Invention] As mentioned above, conventional soldering devices tend to produce products with short-circuited soldering, etc., even though they have minute conductor spacing.
In order to prevent this, soldering had to be done with a soldering iron, which was time-consuming.Also, if there were electronic components already installed, a sudden temperature shock would be applied to these electronic components, causing them to fail. There was a problem that it was easy to induce. Therefore, an object of the present invention is to be able to perform soldering by pushing up the liquid level of molten solder in a spot shape.
Therefore, it is an object of the present invention to provide a new soldering device that can solve the above problems.

[Means for solving the problem] In order to solve the above problem, we developed a soldering device as summarized below. That is, as a device for immersing lead terminals of electronic components in a tank containing molten solder and soldering the terminal portions, the solder tank is an airtight container with a ceiling (molten solder storage tank). At least one tube (molten solder elevating tube) is provided on at least a part of the plate surface, the tube having an open upper part through which the molten solder can freely move up and down, and on the other hand, a volume into which the molten solder is immersed is provided. A pressing member that raises and lowers the liquid level of molten solder by changing the pressure, and a moving pressing member that stores the pressing member and has the function of moving or fixing the pressing member while freely adjusting the volume immersed in the solder. - A new soldering device was developed in which the fixing mechanism was installed in a part of the molten solder storage tank and these were integrated. By using this device and changing the immersion volume of the pressing member, it is possible to push up the solder into the upper release pipe (molten solder elevating pipe), supply the solder into the pipe, and perform soldering at the upper part of the pipe. did.

[Function] According to the present invention, the tube (molten solder elevator tube) having an opening provided on the ceiling surface of the sealed tank is a tube having a minute inner diameter, and has a cylindrical shape, an elongated slit shape, or a rectangular shape. These tubes have cross-sections of various shapes, such as columnar tubes, and these tubes are arranged so that the lead terminals of electronic components mounted on the printed circuit board are accurately inserted into the tube from the top of the tube. There is usually one, but usually more than one.

Separately from the molten solder elevator tube, a pressing member and a mechanism for moving and fixing the pressing member are provided on the ceiling surface of the molten solder storage tank, and the pressing member can be moved up and down to freely increase the volume into which the molten solder is immersed. Make it possible to change. When soldering, the immersion volume of the pressing member is increased to raise the liquid level of the molten solder, and the molten solder is pushed up into the molten solder elevating tube to supply the solder to the upper part of the tube. 1. Place the lead terminal in contact with the upper end surface of the tube so that the lead terminal hangs inside the elevator tube, and solder at the top of the tube. Since the lead wire of the electronic component inserted into the opening of the chain tube and the conductor on the board are properly soldered.

In this way, a separate molten solder elevating tube is installed in the area where the lead terminal to be soldered is located, and solder solution is supplied only to the area where the elevating tube is installed, and solder solution is not supplied to other areas, so that the solder solution is not supplied to the other areas. The parts that should not be short-circuited with lead terminals, etc., and that should be avoided from thermal shock are reliably isolated from the solder elevating tube, so they do not come into contact with molten solder, and therefore the parts that need to be protected from thermal shock are not exposed to the molten solder. The components are not subjected to thermal shock from the heat of molten solder.

[Example] FIG. 1 is a sectional view of a main part of an embodiment of the present invention.

The circuit board 5 is placed in such a way that the lead wires 4 of the electronic components 3 hang down inside the molten solder elevator tube 2 provided on the top surface of the solder tank 1.
is located.

The solder in the tank is melted by the heating of the heater 6, and the pressing member 8 is pushed down by the adjustment of the pressing member moving/fixing mechanism 7, and the molten solder 9 is raised to the upper opening end surface of the solder elevator tube 2.

The molten solder rises in the solder elevating tube by being pushed down by the pressing member, and comes into contact with the lead wires of the electronic components and the conductor circuits on the wiring board.

FIG. 1 is a schematic sectional view showing an outline of the above state.

Figure 2 shows each process in which the lead terminal is inserted into the molten solder elevating tube in advance, and then the pressing member is immersed into the molten solder to raise the molten solder liquid level in the elevating tube to perform soldering. This is an explanatory diagram for explaining, and by showing an enlarged view of the molten solder elevating tube portion of FIG. 1, the state in which molten solder rises inside the tube by a pressing operation and soldering of lead wires is performed is shown. are shown in order.

That is, ■ indicates that the electronic component 3 is placed inside the upper opening of the molten solder elevator tube 2.
The lead wire 4 is inserted, and the pressing member 8 adjusted by the vermilion pressing member moving/fixing mechanism 7 is shown only slightly pushed into the molten solder.

(2) The pressing member is pushed down further, and the molten solder level in the tank rises in response to the volume of the pressing member immersed into the molten solder 9, and as a result, the molten solder rises in the solder elevator tube. This shows the state in which the tip of the lead terminal 4 has been reached.

(2) The pressing member is pushed down further and descends to a predetermined depth, and the molten solder further rises in the elevator tube and reaches the position where it touches the bottom surface of the board, causing the solder to come into contact with the lead terminal and the conductor circuit on the board surface. Indicates the status.

(2) indicates that the pressing member has begun to be pulled up, the liquid level of the molten solder has descended in the elevator tube, and the lead terminal and the conductor circuit on the board surface have been soldered.

The device of the present invention is a device that can perform soldering by repeating the steps (1) to (3) above. However, in the above example, the lead terminal is inserted into the molten solder elevating tube in advance, and then the molten solder liquid level is raised to perform soldering, but the method of using the device of the present invention is limited to this mode. It's not something you can do.

That is, for example, the liquid level of the molten solder is raised in advance to the open end of the upper part of the molten solder elevating tube, and while maintaining that state,
Soldering can also be carried out by inserting the lead terminal into a molten solder elevating tube, which also has the effect of improving productivity.

In the above example, the shape of the pressing member 8 in the device of the present invention is a columnar body with the same cross-sectional area. If the shape is shaped like a pestle with a conical depression, the molten solder level will change greatly at the beginning of insertion of the pressing member, but once the depression reaches the part, the rate of rise in the liquid level will decrease even if the insertion depth increases. becomes smaller. Therefore, even if the insertion speed is the same, the rate of change in liquid level rise can be reduced, making fine adjustment easier and increasing the degree of freedom in tank design.

[Effects of the Invention] According to the present invention, it is possible to easily solder even a downsized printed circuit board with fine lead wire spacing without shorting. In addition, since adjacent electronic components are not immersed in molten solder, they are not subjected to thermal shock, and therefore, there is an effect that thermal shock does not harm the electronic components. Productivity is improved because soldering for manufacturing printed circuit boards that are miniaturized and mounted with high-density components can be easily performed.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing the outline of the main parts of the device of the present invention. FIG. 2 is an explanatory diagram showing the mechanism by which soldering is performed by process when soldering is performed using the apparatus of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of the cross-sectional shape of the pressing member of the device of the present invention. Explanation of symbols 1...Solder tank 2...Melted solder elevator tube 3...Electronic components 4...Lead wire 5...Circuit board 6...Heater 7...・Press member moving/fixing mechanism 8...Press member 9...Melted solder

Claims (1)

[Scope of Claims] An apparatus for soldering electronic component lead terminals by immersing them in a tank holding molten solder, which comprises: (a) a molten solder storage tank consisting of an airtight container with a ceiling plate; (b) A molten solder elevating tube consisting of a tubular body with at least one opening at the top attached to a part of the ceiling plate; (c) The liquid level of the molten solder can be adjusted by changing the volume immersed in the molten solder. a pressing member for raising and lowering;
and (d) a pressing member moving/fixing mechanism for moving and fixing the pressing member while adjusting the volume of the pressing member immersed in the molten solder, the pressing member being pushed into the molten solder and the volume immersed in the solder. By changing the molten solder level, the level of the molten solder can be raised until it reaches the level of the upper opening end of the molten solder elevator, thereby causing the lead previously arranged to hang from the opening into the inside of the solder elevator. A soldering device characterized in that it is configured to be able to solder a terminal to a conductor portion on the surface of a circuit board for fixing the lead terminal.