JPH03202492A - Production of reflow-tinned wire - Google Patents

Abstract

PURPOSE:To produce a reflow-tinned wire having uniform external appearance by heating and melting a tinning film on a metallic wire passed into a reflow heating furnace and then carrying out quenching by spraying the wire with water from the position below the wire at specific contact angle while conveying the wire horizontally. CONSTITUTION:A metallic wire of copper, iron, etc., is electroplated with tin or solder. The resulting plated wire is horizontally passed into a reflow heating furnace to undergo the heating and melting of a plating film. Successively, the wire having the plating film in a molten state is taken out from the heating furnace, and, while conveying the wire horizontally, water is sprayed from the downside of the wire toward the direction of advance of the wire to carry out quenching. At this time, the angle (theta) formed by the wire and the water contact surface is regulated to <=80 deg.. Further, it is preferable to regulate the temp. of the above water to 30-70 deg.C. By this method, equipment cost and space can be reduced, and the wire reflow-plated with tin or solder free from quench stain and having uniform external appearance can be obtained.

Description

[Detailed Description of the Invention] The present invention relates to a method for producing reflow tin and solder-plated wire rods, and particularly to a method for producing reflow tin and solder-plated wire rods, and in particular, a method for manufacturing reflow tin and solder-plated wire rods, which produces a uniform appearance that does not cause appearance defects caused by the reflow process such as quench tin. The present invention relates to a method of manufacturing a reflow plated wire having the following properties.

Indigo ischium strained tin and solder plating materials have excellent electrical connectivity and
Because it has solderability, it is often used as a plating for various copper-based alloys and iron-based alloys. In recent years, as the reliability required for electronic components has become higher and higher, and as mounting technology, as exemplified by SMT, has progressed rapidly, higher quality tin and solder plating has been required. There is. In response to this, reflow plating, which is superior in quality to bright plating, is increasingly being used for pots and solder plating for electronic components.

Traditionally, material reflow technology involves continuously passing metal strips, electroplating tin or solder, and then reflowing the material. It was being used. On the other hand, as the use of these strip-plated continuous reflow-treated materials progresses, reflow treatment of tin and solder plating of wire rods, which are used mainly as male pins for terminals and connectors, and lead materials for electronic components, is being considered and is already in use. It's starting to happen. One method for solder plating of wire rods is to first electroplate the wire while moving it horizontally or up and down in the same way as for strips, and then pass the wire through a reflow oven while feeding it vertically downward, where it is plated. Heat and melt the film.

Furthermore, the molten film is continuously passed vertically into a water tank to quench the molten film. This method has a feature that during quenching, there is little variation in the quenching conditions around the outer periphery of the wire, so there is very little variation in quality, including appearance. However, if the reflow and quenching are performed in the vertical direction, there is a problem in that it is disadvantageous in terms of installation space, equipment cost, operating cost, etc.

Further, in the method of quenching the wire while conveying it horizontally, it is difficult to uniformly quench the outer periphery of the wire, resulting in appearance defects such as quench staining.

The present invention has been made in order to solve the problem of ridges, and in the production of reflow tin or solder plated wire, it is possible to produce a uniform product without causing defects in appearance due to the occurrence of quench stain, etc. It is an object of the present invention to provide a method for manufacturing a reflow plated wire having a good appearance.

i ° The present invention is to electroplate tin or solder on a metal wire, and then
In a method for manufacturing reflow-plated wire rods in which the plating film is heated and melted, the plated wire rod is passed horizontally into a reflow heating furnace to heat and melt the plating film, and then the plated wire rod is continuously conveyed horizontally and advances from the bottom of the wire. It is characterized by quenching by spraying water so that the angle between the line and the surface in contact with the water is within 80'.

In the present invention, any of copper and copper alloys such as copper, brass, and phosphor bronze, or iron and alloys thereof such as iron, stainless steel, and nickel alloys can be used as the wire rod. These wire rods are continuously fed out from a payoff reel and are subjected to cleaning and activation treatments such as degreasing and pickling using known methods.

For metals that are difficult to activate, such as stainless steel, we apply nickel or copper strike plating to improve adhesion.

Subsequently, if necessary, a base plating layer of nickel, copper, or the like may be provided.

Then, top plating, tin or solder, is electroplated. Known methods can be used for tin and solder electroplating baths, conditions, etc., and the present invention is not limited thereto. That is, for tin plating, various baths are known, such as sulfuric acid baths, borofluoride baths, and alkaline baths, and electroplated films can be formed from these baths at appropriate temperatures and cathode current densities. Although a desired plating thickness can be obtained, in practice, the plating thickness is generally about 1 to 5 μm.

The most common solder is an alloy of tin and lead, and the lead is 60 to 95-1.
% is often used. However, the present invention is equally applicable to alloy based coatings such as bismuth and other known solder alloy components. The solder plating bath is also a borofluoride bath,
Various sulfonic acid-based organic acid baths are known.

The wire thus electroplated with tin or solder may be subjected to a Franks treatment before being passed through a reflow oven.

The electroplated wire is passed through a horizontally set reflow oven, and the electroplated film is heated above its melting point and melted. As the reflow furnace, methods using various furnaces such as a butane combustion furnace, an electric furnace, an infrared furnace, an induction heating furnace, etc. are known. The atmosphere may be air, an inert gas such as nitrogen or argon, or a reducing gas such as hydrogen. Take out the wire with the film still in a molten state from the reflow oven and immediately quench it.

The quenching is carried out by applying water to the wire from below the wire, from the rear toward the front in the direction of travel of the wire, as illustrated in the attached drawing. At that time, adjust so that the angle θ formed by the water surface in contact with the line is within 80°. If the angle is larger than that, that is, if the spray is vertically upward from the bottom of the line, the quench on the bottom and top sides of the line will be uneven, resulting in a difference in appearance due to quench staining, etc.

Furthermore, it is particularly preferred that the water temperature be between 30 and 70°C to minimize quenching.

The wire is then dried and wound on a pick-up reel.

According to the present invention, it is possible to save space on a reflow-plated wire line, reduce equipment costs and running costs, and manufacture tin or solder reflow-plated wire that has a uniform appearance with almost no quench stain. .

The present invention will be specifically explained below using Examples.

Continuously run a 0.64i++w square phosphor bronze wire on the back side, ■ Degrease in an alkaline electrolytic degreasing tank at a current density of 5A/da for 20 seconds, ■ Wash with water for 3 seconds, ■ Pickle with 5% sulfuric acid for 5 seconds. , followed by copper base plating and 9/9 under the following conditions.
1. Solder plating was applied.

1) W4 plating bath Composition: Cu5Oi, 5Hz0 250
g/ IHzSOa 100g/ 1 Cathode current density 4^/da" Temperature Room Mildness 0.5 μm 2) 9/1 solder plating bath set Nibo-tin difluoride 21g/ 12-lead borofluoride 165g/ 1 Borofluoric acid 125g / 1 Hydrolic acid 25g/ 1 Peptone 0.5g/it Cathode current density 2A/d+w” temperature
degree 15 °C thickness
The solder-plated wire that came out of the 1.5 μM solder plating tank was then washed with water for 3 seconds, hot water (80° C.) for 3 seconds, dried, and passed through a reflow oven in a horizontal state. The reflow furnace was an electric furnace in which the solder plating tank was heated and melted in an atmospheric atmosphere of 800"C with a residence time in the furnace of 4 seconds. Immediately after this, the solder plating bath was heated and melted using the method shown in the figure at θ70' and the water temperature was 50°C.
was quenched by pouring water over it.

The thus produced reflow solder plated wire was quenched and had a uniform appearance.

[Brief explanation of drawings]

The figure shows the state in which water is applied to a plated wire when quenching the wire. Angle between line and water surface

Claims (2)

[Claims] (1) In a method for producing a reflow plated wire rod in which a metal wire is electroplated with tin or solder and then the plating film is heated and melted, the plated wire rod is passed through a reflow heating furnace horizontally to heat and melt the plating film, and then the plating film is heated and melted. Reflow plated wire is quenched by spraying water on it from the bottom of the wire in the direction of travel so that the angle between the wire and the surface in contact with water is within 80° while being transported horizontally. Production method. (2) The method for producing a reflow plated wire according to claim (1), wherein the water temperature is 30 to 70°C.