JPH1147976A - Ribbon-like or washer-like flux-cored solder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the ribbon-like or washer-like flux-cored solder in which the inter-layer separation is prevented and the flux is not irregularly present by rolling the thread solder where the flux is built in a curved state. SOLUTION: The flux-cored solder is twisted to build the flux 5 in the curved state. To apply the twist, a reel is turned in the plane perpendicular to the pushing-out direction when the solder is extruded in a wire-like condition from an extrusion die and wound around the reel. The effect preventing the inter- layer separation is improved by increasing the twisting number so that the twisted thread solder is not cut off, and building the plurality of cores of the flux 5. The twisted thread solder is passed through rolling rolls 4, 4' to form a ribbon-like solder 3', and it is punched to form a washer-like solder 3". Because no flux is irregularly present in the center by building in the plurality of cores of the flux 5, the defectives including separation are greatly reduced, and the workability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ribbon-shaped or washer-shaped flux-cored solder which prevents delamination between layers.

[0002]

2. Description of the Related Art A ribbon-shaped or washer-shaped solder has conventionally been manufactured as follows. (1) A solder alloy is formed in a plate shape and cut into a ribbon shape, or formed into a linear shape and pressed into a ribbon shape.

(2) A powder solder and a flux (dust) are mixed and formed into a ribbon.

(3) Solder containing flux (dust)
Rolled to form a ribbon. The washer-shaped solder was formed by punching the ribbon-shaped solder formed as described in (1) to (3) into a washer shape.

[0005] In the method (1), since no flux is present, it is necessary to apply the flux at the time of use.

In the method (2), since the flux and the solder alloy powder are mixed and pressed, when a small-diameter washer-like solder is produced, defective press-out or defective shape (no flux is contained or unevenly distributed) is caused. Easy to occur.

[0007]

The method of the above (3) is as follows.
Although there is an advantage that it is not necessary to separately apply a flux, there is a problem that peeling frequently occurs depending on the ribbon width or the washer diameter because the solder plate and the flux are layered. In addition, since the flux is unevenly distributed in one place, there has been a problem that the flux may be broken or the flux may be scattered during the operation.

The present invention has been made in view of such a point, and an object of the present invention is to provide a ribbon-shaped or washer-shaped flux-cored solder which prevents delamination and has no uneven distribution of flux.

[0009]

According to the above-mentioned object of the present invention, the present invention is characterized in that a thread solder in which a flux is built in a curved shape is rolled.

[0010] In order to incorporate the flux in a curved shape, twist may be added to a normal flux-cored yarn solder.

Conventionally, flux-containing solder has been limited to one having a built-in flux. However, in the present invention, it is preferable to incorporate a plurality of fluxes. By incorporating a plurality of cores, delamination becomes more difficult.

[0012]

Next, an embodiment of the present invention will be described. Figure 1 shows how to add twist to fluxed solder.
As shown in FIG. 1, when the wire is extruded linearly by the extrusion die 1 and wound around the reel 2, the reel 2 may be rotated in the front-rear direction in FIG. To the extent that the thread solder does not cut,
By increasing the number of twists, the effect of preventing peeling is further improved.

The twisted thread solder 3 is passed through rolling rolls 4 and 4 'to form a ribbon 3' as shown in FIG. This is punched out by a standard method,
It is formed into a washer shape 3 ″.

In the above embodiment, the wire solder 3 has
Flux 5 (tarnish or other activator) is incorporated in three cores. By incorporating a plurality of cores in this manner, the flux is not unevenly distributed at the center, so that the cracking rate at the time of rolling or the defective peeling rate at the time of punching a washer is greatly reduced. Further, since the dispersibility of the flux is improved, the workability is 30%.
% Or more.

As the solder alloy and the flux used in the present invention, any of those used for this purpose can be used and are not particularly limited.

[0016]

EXAMPLE Using a Pb-Sb-based solder alloy, three cores of rosin-based flux were incorporated, and a ribbon-shaped solder 3 '' was produced from the stranded solder 3 'as described above.

FIGS. 3 and 4 show micrographs of the twisted-wire solder 3 ', and FIGS. 5 and 6 show micrographs of the ribbon-shaped solder 3''.

As shown in FIGS. 3 and 4, and FIGS. 5 and 6, the flux is not continuous linearly in both the vertical and horizontal directions. It is considered that cracks during rolling are effectively prevented and delamination of the solder product is effectively prevented since there are portions that are also continuous in the lateral direction.

According to the present invention, since the flux is rolled while being incorporated in a curved shape, the flux is incorporated without being unevenly distributed, so that not only is it difficult to peel off, but also the flux is cut off extremely during use. In addition, the flux is less scattered and a soft welding operation can be performed. Therefore, work efficiency is significantly improved.

Since the solder of the present invention is hard to be peeled off even if it is small, it is particularly suitable for use as a pull solder used for soldering a narrow pitch foot of an IC.

[0021]

According to the present invention, not only is it difficult to peel off, but also the flux is not unevenly distributed in the center, so that the amount of flux cut off during use is extremely small, the scattering of flux is small, and a soft welding work is possible. Therefore, work efficiency is greatly improved.

Further, by applying twist to the thread solder containing the flux, the flux can be easily incorporated in a curved shape.

Further, by incorporating a plurality of cores, the uniformity and multi-directionality of the incorporated flux are enhanced, and the effect of the present invention is further enhanced.

[0024]

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of applying twist to a thread solder of the present invention.

FIG. 2 is a schematic view showing the production of the solder of the present invention.

FIG. 3 is a photomicrograph of a cross section of the thread solder manufactured in the example.

FIG. 4 is a photomicrograph of a longitudinal section of a thread solder manufactured in an example.

FIG. 5 is a micrograph of a cross section of the ribbon-shaped solder manufactured in the example.

FIG. 6 is a photomicrograph of a longitudinal section of a ribbon-shaped solder manufactured in an example.

[Explanation of symbols]

 3 Twisted thread solder 3 '... Ribbon solder of the present invention 3 "... Washer solder of the present invention 4, 4' ... Rolled roll

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI B23K 35/40 340 B23K 35/40 340E

Claims (3)

[Claims] 1. A ribbon-shaped or washer-shaped solder in which a flux containing a flux in a curved shape is rolled to prevent peeling between layers. 2. A wire solder having a built-in flux, which is twisted to have a built-in flux in a curved shape.
Solder described in. 3. The solder according to claim 1, wherein a plurality of cores are contained in the flux.