US3676322A

US3676322A - Apparatus and method for continuous production of electrolytically treated wires

Info

Publication number: US3676322A
Application number: US891A
Authority: US
Inventors: Yoshihiro Kamata; Takashi Hirose
Original assignee: Furukawa Electric Co Ltd
Current assignee: Furukawa Electric Co Ltd
Priority date: 1970-01-06
Filing date: 1970-01-06
Publication date: 1972-07-11
Anticipated expiration: 1989-07-11
Also published as: DE2008606B2; DE2008606A1; GB1302793A

Abstract

Apparatus and method for continuously producing electrolytically treated wires which comprise immersing a wire repeatedly in an electrolyte contained in an electrolytical treatment tank positioned between guide rolls which passing the wire continuously back and forth between the guide rolls by guiding the wire stepwise on the guide rolls, using the wire as an electrode and providing another electrode within the electrolytic treatment tank to effect electrolytic plating and/or polishing at a high production efficiency.

Description

United States Patent Kamata et al. [4 1 July 11, 1972 [541 APPARATUS AND METHOD FOR 2,495,695 1/1950 Carmin et a1. ..204/209 CONTINUOUS PRODUCTION OF 3,259,557 7/1966 Smith et a1 .204/28 ELECTROLYTIC ALLY TREA D 3,436,330 4/1969 Wright et al., ..204/207 WIRES TE 830,093 9/ 1906 Meaker ..204/206 2,876,191 3/1959 Bachman... ....204/207 [72] 1mm: g 'f'ggy figzl Takashi FOREIGN PATENTS OR APPLICATIONS ssig The F ukawa Company Lilnited, 1 Great T k 0 Japan Primary ExaminerF. C. Edmundson Filedi J 1970 Altomey-McGlew and Toren [21] Appl. No.: 891 ABSTRACT [52] U S Cl 204/206 204/28 204/40 Apparatus and method for continuously producing electrolyti- I o t i i v n t t 9 5i a re- [51] Int Cl C23b C23b 5/58 C23!) 5/6'8 peatedly in an electrolyte contained in an electrolytical treat- [58] Fieid 6 ment tank positioned between guide rolls which passing the wire continuously back and forth between the guide mus y guiding the wire stepwise on the guide rolls, using the wire as [56] References Cited 1 an electrode and providing another electrode within the elec- UNITED STATES PATENTS trolytic treatment tank to effect electrolytic plating and/or polishing at a high production efficiency. 2,293,810 8/1942 Domm ..204/28 2,497,894 2/1950 Luke ..204/28 5 Claim, 4 Drawing Figures APPARATUS AND METHOD FOR CONTINUOUS PRODUCTION OF ELECTROLYTICALLY TREATED WIRES therefore a very long electrolytic cell has been required in case a long time treatment is necessary. And in case a plurality of wires are treated at a time, the electrolytic cell must have also a considerably large width.

Further, such a conventional apparatus has a defect that the cost of electrolytic treatment is high due to the necessity of a large amount of electrolytic, the difficulty in maintenance of electrolytic and poor working efficiency.

Therefore, one of the objects of the present invention is to overcome the above defects and to provide an apparatus which permits a continuous electrolytic treatment of metal wires at high efficiency. The main feature of the present invention lies in an apparatus and method for producing electrolytically treated wires, which comprises a means for guiding metal wires to be treated, at least one pair of guide rolls serving also as electrode contacts and an electrolytic treatment tank containing an electrolyte in which the metal wires are immersed, said guide rolls being positioned outside the electrolyte, said electrolytic treatment tank being provided with one electrode, and said metal wires serving as another electrode connected to said guide rolls.

The apparatus and method for producing electrolytically treated wires according to the present invention may be also useful for both electrolytic polishing and electro-plating of metal wires, and particularly in case of electro-plating of metal wires where the wires are repeatedly passed in and out of the plating bath to give a multiple layers of plating the present invention is advantageous in that multiple layers of electro-plating of desired thickness having better adhesiveness, because when the wires are taken out of the plating tank during the repeated passing in and out of the plating tank, the surface of the plated wires can be maintained in wetted condition by liquid shower or liquid spray.

In one embodiment of the present invention, the electrolytic treatment tank is provided with slits at the inlet and the outlet thereof for passing the wires and preventing the electrolyte, and a forced circulation system for the electrolyte is used for forcedly returning the electrolyte which flows out of the inlet and outlet to the electrolytic treatment tank so that a constant amount of electrolyte is maintained in the electrolytic treatment tank.

Regarding the guide rolls, their rotating shafts may be horizontal or perpendicular, and the means for guiding the wires provided on the guide rolls may be conveniently a plurality of grooves provided around the circumferential surfaces of the guide rolls.

The wires to be treated according to the present invention are pretreated in a pre-treatment tank as required.

For better understanding of the present invention, one embodiment of the present invention will be described referring to the attached drawings in which:

FIG. 1 to FIG. 4 show respectively one embodiment of the apparatus for producing electrolytically treated wires according to the present invention;

FIG. 1 is a plane view,

FIG. 2 is a side view,

FIG. 3 is a slant view of the guide rolls and FIG. 4 is a slant view of the electrolytic.

In FIGS. 1 and 2, 1 is an electrolytic treatment tank, 2 is an electrical conductive guide roll, 3 is a shaft of the guide roll 2, 4 is a groove on the circumferential surface of the

guide roll

2, 5 is a wire to be treated, which is used as cathode in case of an ordinary electro-plating, and is used as anode in case of electrolytic polishing, 6 is an electrode plate arranged within the electrolytic treatment tank 1, which plate is used as an anode in case of electro-plating and used as cathode in case of electrolytic polishing, 7 is a contact which is contacted with and rotated by the

guide roll

2, 8 is a distribution line, 9 is an electric power source for the electrolysis, 10 is a feeding drum, 11 and 12 are respectively pretreatment equipment, 13 and 14 are respectively after-treatment equipment, and 15 is a coiling drum. In FIG. 3 which is a slant view showing the guide roll 2 in operation, a plurality of guiding grooves are made on the circumferential surface of each of the two

guide rolls

2a and 2b, so that the wire 5 to be treated is wound and received in these grooves as shown in the drawing and is delivered in the direction shown by an arrow as the

guide rolls

2a and 2b rotate. FIG. 4 is a slant view of the electrolytic treatment tank 1 in which the wire to be treated travels in the direction shown by an arrow.

- In the embodiment of the present invention shown in the drawings, two electrolytic tanks la and lb extending in the travelling direction of the wire 5 are arranged in parallel to each other, at both ends of these two treatment tanks are arranged the

guide rolls

2a and 2b each vertically and rotatably. These'rolls 2a and 2b are connected to the electrodes of the electric power source 9 through contacts, and the electrolytic treatment tanks la and lb are also connected to the power source 9 through the electrode plate 6. 16 is a dividing plate positioned in the tank inward the wire inlet and the wire outlet, and 17 is a side wall of the treatment tanks la and lb.

In the above embodiment each of the dividing plate 16 and the side wall 17 is provided with narrow slits I8 and 19 respectively for passing the wire therethrough. Thus, the wire 5 passes through the

slits

18 and 19 and advances without contacting the dividing plate 16 and the side wall 17 of the tank. The electrolyte contained in the central portion defined by the dividing plates 16 in the tank 1 drops through the slit I8 into a space 20, but returned into the central portion of the treating tank by a circulating system (not shown in the drawings) for repeated use. By suitable selection of the slit size and the circulating system, the loss of electrolyte is advantageously avoided.

The wire 5 delivered out from the delivery drum 10 passes through the

pre-treatment tanks

11 and 12 and is guided into the lowest groove 4a on the guide roll 2a, then passes through the electrolytic treatment tank In into the lowest groove 4b on the guide roll 2b, and passes through the electrolytic treatment tank 1b into the groove 4c next to the lowest on the guide roll 2a.

The wire 5 passes from the guide roll 2a through the electrolytic treatment tank la, the guide roll 2b, the electrolytic treatment 2b into the top groove 48 on the guide roll 2b and then passes through the after-

treatment tanks

13 and 14 and is coiled on the winding drum.

In the above embodiment of the present invention, the treatment tanks, the slits and the guide rolls are described as being in a tandem arrangement. But the same principle can be applied when the treatment tanks, the slits and the guide roll are arranged in parallel. In this way, the wire 5 is subjected to electrolytic treatment during its passage through the electrolytic tanks 1a and 1b.

According to the present invention, a very high efficient and excellent electrolytic treatment can be attained as clearly understood from the following examples.

EXAMPLE 1 A brass (Cu 65%, Zn 35%) wire of 2 mm diameter coiled on a delivery drum 10 was taken out from the drum and immersed in NaOH aqueous solution for several seconds, washed with water and them subjected to nickel plating in the plating apparatus according to the present invention as under,

The composition of the nickel plating bath:

Nickel sulfate 250 g/l Boric acid 30 gll Nickel chloride g/l The guide rolls were made of 25 cm diameter stainless steel rolls and rotated at a constant speed of 15 rpm to obtain the wire speed of 11.8 m/min. The length of the nickel plating bath in each of the two tanks was in and the wire was wound in 30 stepwise so that the length of the total immersed wire was 300 meters (30 steps X 2 tanks X 5m). The input current density was 5 A/dm at 100 percent current efficiency so that the thickness of nickel coated on the brass wire was 25 micron,

In order to attain the same level of production rate as above by a conventional plating method used for the production of nickel plated brass wire. Such an extraordinary length of plating tank as 300 m at least is required, and on the other hand the production rate will be about 1/60 if the production is made at a similar floor area as shown in this example.

EXAMPLE 2 A steel wire of 20 mm diameter coiled on a delivery drum was immersed for several seconds in an aqueous solution of orthosodium silicate, washed with water, and then subjected to copper electro-plating for 1 minute in an electrolyte containing 20 g/l of copper cyanide, 43 gll of potassium cyanide, and again washed with water, subjected to stick tin-plating, washed with water, dried and coiled on the drum 15. The above thick tin-plating was done as under.

The plating bath contained 120 g/l of potassium stannate only. The guide rolls 2 were titanium rolls of 25 cm diameter and rotated at a constant speed of 15.0 rpm so that the speed of the copper plated steel wire was 11.8 m/min. The bath length in each of the two treating tanks was 5 m and the wire was wound in 30 stepwise so that the total length of immersed wire was 300 meter (30 steps X 2 tanks X 5 m). The imput current density was 283 A/dm at current efficiency of 85 percent so that the thickness of tin coated on the copper plated wire was 10.5 micron.

In order to attain the same level of production rate as above by a conventional plating method used for the tin-plated steel wire, such an extraordinary length of plating tank as 300 meters at least is required, and a considerable additional width of tank will be required even in case of a multiple electroplating is effected. On the other hand, the production rate will be about 1/50 if the production (plating) is made at a similar floor area as shown in this example.

EXAMPLE 3 In this example, the same electro-plating apparatus and the same wire speed as in Example 2 were used for cadmium plat ing. A brass wire of 1.5 mm diameter was pre-treated in a similar way as in Example 1 and plated with copper and subjected to a thick cadmium plating in a bath containing 30 g/l of cadmium oxide and 120 g/l of sodium cyanide at a current density of 565 A/dm to obtain 35 micron thickness of uniform cadmium plating on the wire under the same plating conditions as in Example 1.

The tin-plated steel wire obtained in Example 2 and the cadmium-plated brass wire obtained in Example 3 were found to be free from surface crachings and to have uniformity and high adhesion.

From the above description, it will be understood that a large equipment requiring a very large floor area as needed in the conventional arts is not necessary in the present invention, and much easier quality control and better working efficiency and thus much economical advantages as well as the technical advantages that better quality of plated wire can be obtained in the present invention.

EXAMPLE 4 Pure copper wire of 3.0 mm diameter coiled on the delivary drum 10 was degreased for 30 seconds in trichlor ethylen vapor, then subjected to polishing in an electrolytic polishing apparatus according to the present invention, and washed with water, dried and coiled. The electrolytic polishing was done as under. The electrolyte was a phosphoric acid (specific gravity 1.5 g/cm") streight composition. The electrolyte was effected at 25 C., at current voltage of 1.6V. The guide roll 2 in the inventive electrolytic polishing apparatus was made of titanium having 25 cm diameter, and rotated at a constant speed of 5.1 rpm so that the wire speed was 4 m/min. Two electrolytic treatment tanks were used. The length of treating bath in each of the tanks was 1 m, and the wire was wound in 30 stepwise so that the total length of wire immersed in the electrolyte was 60 m (30 steps X 2 tanks 1m).

The immersion time (polishing time) is calculated from the above factors as 60 m 4 m/min. 15 min.

As clear from the above, the inventive apparatus is one having such an extraordinarily high working efficiency as permits a high-speed electrolytic polishing of 4 m/min. in a tank havingonly one meter length for as long as 15 minutes. In this example, the copper wire having a large diameter and high electrical conductivity was used. if wires such as steel wires of less electrical conductivity and smaller diameter are treated, further advantages can be obtained, for in case of a long time electrolytical polishing of steel wires in a conventional apparatus, it is necessary to provide current contacts at many various points, if the current is input to the wire used as the electrode, thus a very high level of equipment cost is required.

As described above, the present invention can eliminate the efect of a conventional apparatus that a very large apparatus occupying a large floor area is required, and can provide remarkable advantages that the quality control in electrolytic treatments is much easier, that better working efficiency and thus a very high economy can be obtained as well, that a good quality of electrolytically treated wire can be obtained, that particularly the anode (in case of electroplating) can be easily and continuously supplemented, and that intermediate electrode contacts needed by an ordinary apparatus for a long period treatment can be substituted by the grooved rollv The apparatus of the present invention is useful for a very wide range of applications and can be used for all kinds of electrolytic treatments and can produce all kinds of electrolytically treated wires only by selection of the electrolyte, the groove number on the contact roll, the wire speed and the connection to power source.

What is claimed is:

1. Apparatus for electrolytic treatment of wire comprising tank means containing electrolyte therein, a pair of rollers positioned on opposite sides of said tank means, said rollers being formed of electrically conductive material, counter electrode means located within said tank means, said wire to be treated being spirally wound in a continuous manner about said rollers and extending back and forth therebetween and through said tank means, means forming an electrical circuit path externally of said tank means between each of said rollers and said counter electrode means thereby to form within said tank means an electrolytic cell including said wire as an electrode thereof, said rollers being located completely externally of said tank means, and wall means located interiorly of said tank means and defining slots through which said wire extends for retaining said electrolyte within said tank means while enabling said wire to pass into and out of said tank means, said tank means being totally devoid of rollers on the interior thereof.

2. Apparatus according to claim 1, wherein said rollers each comprise an axis of rotation arranged parallel to each other and wherein said slots extend in a direction parallel to said axes.

3. Apparatus according to claim 1, wherein said counter electrode means comprise a pair of electrodes juxtaposed on opposite sides of said wire passing within said tank means, said pair of electrodes each extending for equivalent distances across the length of said wire.

4. Apparatus according to claim 1, wherein said tank means comprise a pair of separate tanks adjacently arranged to have said wire which extends between said rollers pass through one of said tanks in one direction and through the other of said tanks in an opposite direction.

5. Apparatus according to claim 1, wherein said pair of rollers each comprise circumferentially formed grooves on the surface thereof for guiding said wire thereabout.

Claims

2. Apparatus according to claim 1, wherein said rollers each comprise an axis of rotation arranged parallel to each other and wherein said slots extend in a direction parallel to said axes.
3. Apparatus according to claim 1, wherein said counter electrode means comprise a pair of electrodes juxtaposed on opposite sides of said wire passing within said tank means, said pair of electrodes each extending for equivalent distances across the length of said wire.
4. Apparatus according to claim 1, wherein said tank means comprise a pair of separate tanks adjacently arranged to have said wire which extends between said rollers pass through one of said tanks in one direction and through the other of said tanks in an opposite direction.
5. Apparatus according to claim 1, wherein said pair of rollers each comprise circumferentially formed grooves on the surface thereof for guiding said wire thereabout.