JPH03114653A - Method for removing flux - Google Patents

Abstract

PURPOSE:To reduce the expense and to improve easiness of maintenance and the productivity by removing flux stuck to soldered part with spot heating after soldering an electronic parts with lead wire to the other lead wire. CONSTITUTION:A part intersecting U-shape lead wire 1 and the lead wire of a capacitor 3 is soldered with a wire solder incorporating the flux by a soldering device arranged in conveying system while conveying a tape 4. Successively, before conveying the tape, position of a hydrogen burner 8 having slender flame is adjusted. The tape 4 is conveyed at velocity that the soldering part is exposed to the flame. After that, the projecting lead wire is cut at the base position with an edge set to the device. By this method, the soldered part in the electronic parts is made to clean condition without any stickiness by eliminating the flux.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for removing flux attached to the solder parts without using an organic solvent after soldering an electronic component with a lead wire to another lead wire. The present invention relates to a method for removing flux.

[Prior Art] Electrical connections between electronic components and the like are performed using solder made of an alloy whose main components are lead and tin. In soldering,
Flux is used to remove the oxide film on the surface of the parts to be soldered and improve solder wetting.

An example of an electronic component that is made by soldering a component with a lead wire attached to another lead wire is a noise removal filter.

The structure of the T-shaped circuit, which is well known as a noise removal filter, is made by inserting ferrite magnetic cores with through holes into the parallel parts of lead wires that are curved in a U-shape and led out in parallel. One lead wire of a fixed, separately formed axial lead type ceramic capacitor is soldered to the curved part of the lead wire, and the other lead wire is led out parallel to the U-shaped lead wire. be.

The manufacturing method of such a noise removal filter includes a second method.
As shown in Figure (a), a lead wire 1 whose central portion is curved in advance into a U-shape and whose ends are led out in parallel, a ferrite magnetic core 2 having a through hole, and an axial lead type ceramic capacitor. 3 and adhesive carrier tape 4 are prepared.

Once these are prepared, connect the magnetic core 2 to the lead wire 1.
The magnetic cores are fixed to the lead wires with adhesive, and the axial lead type ceramic capacitor 3 is placed approximately in the center between the parallel lines of the U-shaped lead wire 1. The lead wire 1 and the capacitor 3
The U-shaped lead wire ends and one lead wire end of the capacitor are fixed to an adhesive carrier tape 4.

As shown in FIG. 2(b), this method is carried out continuously using holes 7 provided in the carrier tape 4 by a conveying method such as a belt conveyor. Next, the intersection of the U-shaped lead wire 1 and the lead wire of the axial lead type ceramic capacitor 3 is soldered using wire solder containing flux. Thereafter, the protruding lead wire is cut at its base, and then, as shown in FIG. 2(C), the soldering part 5 is immersed in an organic solvent 6 or the like to wash away the flux. Note that the arrows in the drawings indicate the direction of movement of the conveyor.

The reason why it is necessary to clean the flux as mentioned above is that the viscous flux contained in the solder wire dissolves and covers the surface of the soldering part. If electronic parts are used with flux attached to them, they become dirty and inconvenient to handle, and if electronic parts are used with flux remaining, they will absorb moisture during use, and the chlorine contained in the flux will decompose and cause corrosion. This is because there is a risk that quality reliability may be lowered.

[Problems to be Solved by the Invention] According to the above conventional method, after soldering, the flux is immersed in an organic solvent to clean it, so the organic solvent gets dirty and cannot be cleaned unless it is replaced frequently. There were problems in that the organic solvent could not be cleaned thoroughly, it took a lot of time to replace the organic solvent, and the organic solvent was consumed rapidly, increasing costs.

An object of the present invention is to provide a method for removing flux after soldering without using an organic solvent.

[Means and effects for solving the problem] The present inventors,
In order to achieve the above objective, we researched a flux removal method that does not use organic solvents and found that by spot heating the soldering part under selected conditions, flux can be removed without affecting other electronic components. Heading The present invention has been arrived at.

Therefore, the present invention provides a method for removing flux in an electronic component manufacturing process, which comprises soldering a lead wire of an electronic component having a lead wire to another conductor using flux, and then removing the flux. The present invention provides a method for removing the flux, characterized in that the flux is removed by spot heating, for example, with a hydrogen burner flame.

When the flux is heated by exposing it to the flame of a hydrogen burner, the volatile components contained in the flux are evaporated, the oil and fat bones are burned, decomposed, and altered to lose their stickiness and chlorine is removed. The temperature of the flame of a hydrogen burner varies depending on the position of the flame, and the temperature must be selected depending on the object to which the flame is applied. If the temperature and time are selected so as not to interfere with other parts and to increase productivity, the temperature ranges from 1,000℃ to
A suitable time is 0.01 to 0.1 seconds in a temperature range of 3,000°C. This is because at a temperature higher than this, there is an increased risk of damaging other components besides the flux, and at a temperature lower than this, the flux cannot be removed sufficiently. Further, if the flame application time is longer than 0.1 second, the productivity will decrease, which is not preferable, and if the flame application time is shorter than 0.01 second, sufficient removal will not be possible.

Although we have shown an example of using a hydrogen burner as the spot heating means used for flux removal, the method is not limited to this, and heating can be easily performed using means such as laser, infrared rays, and resistance heating, and the temperature and time may vary. You can remove only the flux by selecting conditions that do not affect other materials.

Next, the present invention will be further explained based on examples.

Embodiment FIGS. 1(a) to 1(c) are schematic diagrams for explaining the present invention in detail, and the embodiment will be described with reference to these drawings.

In advance, solder-plated conductive wire with a thickness of 0.5 mm is connected to a length [1
A plurality of lead wires 1 were prepared by cutting them into pieces of 0 mm, bending them at approximately right angles at positions 6 ml 11 from the center of the wire to form a U-shape, and leading out so that the ends were parallel.

Also, length 4.51, diameter 2.0 mm, inner diameter 1.0 mm.
A plurality of ferrite magnetic cores 2 having through-holes of mm in diameter and a long sticky carrier tape 4 were prepared.

Apart from this, the length of the ceramic capacitor body is 4.
An axial lead type ceramic capacitor 3 with a diameter of 0 mm and a diameter of 1.8 mm was prepared.

Next, the magnetic cores 2 were inserted into the parallel portions of the lead wires 1, and the magnetic cores were fixed to the lead wires with an epoxy adhesive.

The carrier tape 4 was conveyed through a conveyance hole 7 provided in the tape, so that the conveyance system could continuously convey the tape.

Next, the axial lead type ceramic capacitor 3 is placed approximately in the center between the two parallel lead wires of the U-shaped lead wires so that the lead wires and the lead wires of the capacitor are parallel to each other. so that the U-shaped lead wire end and one lead end sandwiched therebetween were held and fixed on the adhesive carrier tape 4 (as shown in FIG. 1(a)). )reference).

Next, while conveying the tape 4, a soldering device installed in the conveyance system connects the intersection of the U-shaped lead wire 1 and the lead wire of the axial lead type ceramic capacitor 3 with a thread containing flux. Soldered with solder.

Following this, the length is 1 OI before the tape is transported.
The position of a hydrogen burner with an elongated flame of about nI11 was adjusted.

The soldering involved transporting the tape at such a speed that the section was exposed to the flame for 0.07 seconds. The protruding lead wire was then cut at its base using a blade installed in the device.

Note that the arrows in the drawings indicate the direction of movement of the conveyor (see FIGS. 1(b) and 1(C) above).

In this way, the soldering part of the obtained electronic component is
The flux had disappeared and it was clean and no longer sticky.

[Effects of the Invention] As explained above, according to the method of the present invention, flux can be removed without using an organic solvent. is no longer necessary, reducing costs, maintenance, and improving productivity.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the method of the present invention, and FIG.
Top view showing the U-shaped lead wire and the ceramic capacitor lead wire arranged and fixed on the carrier tape, the same figure (b
) is a top view showing that while the carrier tape is being conveyed, the soldering at the intersection of the lead wires (NI bonding), spot heating of the intersection contact area, and cutting of the remaining capacitor wire is performed, and the same figure (C) is
FIG. 2 is an enlarged perspective view of a spot heating section. FIG. 2 is a schematic diagram showing a conventional noise filter manufacturing method, and FIG. Figure (b) is a top view showing that the lead wire intersections are soldered and the remaining wires of the capacitor are cut while the carrier tape is being conveyed. Figure (c) is a top view showing that the lead wires are exposed to organic solvent after soldering and cutting. It is a side view which shows the immersed state. Explanation of symbols 1... U-shaped lead wire 2... Ferrite magnetic core 3... Axial lead type ceramic capacitor 4
... Carrier tape 5 ... Soldering part 6 ... Organic solvent 7 ... Conveying hole 8 ... Hydrogen burner 0 9 ... Burner flame agent

Claims (2)

[Claims] (1) In a method of manufacturing an electronic component, which involves soldering a lead wire of an electronic component having a lead wire to another conductor using flux, and then removing the flux, the flux is removed by spot heating. A flux removal method characterized by: (2) The method according to claim 1, wherein the spot heating is performed by a flame of a hydrogen burner.