US2876191A - Electroplating apparatus - Google Patents

Description

March 3, 1959 R. J, BACFIMAN $376,191

I ELECTROPLATYING APPARATUS Filed Sept. 5. 1952 lNl/EN TOR R. J. BACHMAN ATTORNEY ELECTROPLATING APPARATUS Robert J. Bachman, Towson, Md., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application September 5, 1952, Serial No. 307,964

4 Claims. (Cl. 204-207) This invention relates to electroplating apparatus, and more particularly to apparatus for electroplating moving wires.

Electrical conductors composed of copper-clad steel may be manufactured advantageously by electrodepositing heavy coatings of copper upon moving steel wires. A great many steel wires may be advanced simultaneously in parallel, side-by-side relationship through a series of electrolytic cells in which anodically charged copper electrodes are located. In between adjacent cells cathodically charged rolls may be provided to electrically contact the moving-wires and to position and guide the wires in their passage through the series of cells.

In order to insure a reliable and highly conductive electrical contact between the rolls and the advancing wires, it has heretofore been considered necessary to place a pair of staggered contact rolls in the air space between adjacent cells. These pairs of rolls have been arranged so that the wires advance in a zigzag path under one roll and over the other. When such system is operated continuously over long periods of time, it has been found that the rolls require frequent repairs. The peripheral surfaces of the rolls that contact the moving wires may become Worn excessively. Furthermore, since the electrically charged rolls inevitably become wetted by electrolyte clinging to the moving wires, metal may be deposited upon or removed from the periphery of the rolls, depending upon operating conditions. Under such circumstances, the labor and expense of maintaining the rolls is at least twice as burdensome as it would be in a satisfactory system requiring only a single contact roll between adjacent tanks.

An object of the invention is to provide new and improved electroplating apparatus.

Another object of the invention is to provide new and improved apparatus for electroplating moving wires.

An apparatus illustrating certain features of the invention may include a series of electrolytic cells aligned in tandem and alternately tilted in opposite directions' A complete understanding of the invention may be had from the following detailed description of electro- "ice I plurality of anodically charged plates 18-18 are immersed in the electrolyte in the cells and are covered with a layer 19 of copper particles, which gradually pass into solution to replenish the supply of metal ions in the electrolyte as the plating process progresses. The plates 18-18 extend along and are parallel to the bottoms of the cells.

In one suitable type of distribution system, electrolyte may be introduced into the cells 12, 13, 14, and 16 through a plurality of supply pipes 20-20 which com- T municate with a plurality of distributors 21-21 having transverse cavities 22-22 therein. The electrolyte enters the cells through a plurality of orifices 24-24 which branch off from the cavities 22-22 and are designed to direct the'incoming solution so that it will flow parallel to the path traveled by the wires 10-10. If desired,

the number of orifices 24-24 may equal the number of wires 10-10, and one orifice may be located directly below each moving wire.

The distributors 21-21 may be molded from hard rubber, or other suitable corrosion resistant material.

Similarly, the sides and bottoms of the several cells may be lined with a corrosion resistant material such as rubber. The tops of the distributors are formed in the shape of weirs 25-25, which are slotted to permit passage therethrough of the wires 10-10 while minimizing the amount of electrolyte which may overflow from the cells. In a like manner, the ends of the cells opposite the ends in which the distributors are located are provided with weirs 26-26. Electrolyte may overflow from the opposite ends-of each cell, be collected in troughs (not shown),

plating apparatus forming a specific embodiment thereof,

when read in conjunction with the appended drawing, in which:

Fig. 1 is a fragmentary side elevation of an electroplating apparatus embodying the'invention, with portions thereof shown in section, and

,Fig. 2 is a fragmentary plan view looking at that portion of the apparatus beneath the line 2-2 of Fig. 1.

A plurality of steel wires 10-10 may be advanced in parallel, side-by-side relationship through a series of individual, equally spaced, electroplating cells aligned in tandem, of which cells 12, 13, 14, 15 and.16 are shown, from right to left as viewed in Fig. 1. These cells contain an electrolyte, such as a suitable copper sulfate and sulfuric acid solution, from which a thick layer of metallic copper is electrodeposited onto the moving wires. A

and be recirculated back into the cells through the supply pipes 20-20. Cells embodying electrolyte distributors and weirs of this type are claimed and described fully in copending application Serial No. 254,989, now' Patent No. 2,737,487, filed November 6, 1951, by V. A.Rayburn, for Electrolytic Apparatus. Y

, In accordance with the present invention, throughout the series of cells a single cathodically charged roll is positioned between adjacent cells in each instance, and similar rolls are positioned at each end of the entire series of cells. Thus, a roll 28 is located between the cells 12 and 13, a roll 29 is present between the cells 13 and 14, a roll 30 lies between the cells 14 and 15, and a roll 31 is mounted between the cells 15 and 16. The elevation of these rollsis uniformly staggered so that successive rolls are positioned at equal distances alternately above and below the path of the wires. Thus, the wires 10-10 pass under the roll 28, over the roll 29, then under the roll 30, and finally over the roll 31, as the advancing wires successively contact the rolls in the order named. Each .of the rolls is mounted rotatably on a pair of vertical walls 32-32 erected on transversely opposite sides of the cells perpendicular to a horizontal platform 34 on which all of the cells are supported. The walls 32-32 also support driving means (not shown) for positively rotating the rolls. Encircling the periphery of each roll are a plurality of equally spaced grooves 36-36 designed to receive the advancing wires 10-10. Obviously, the grooves on each roll are aligned properly with the grooves oneach of the other rolls in order to guide the wires in parallel lines during their passage through the series of cells.

An important feature of the invention is the fact that posite directions at equal angles above the horizontal.

Thus, the cell 12 is inclined so that the wires 10-10 enter this cell at a higher elevation than that at which the wires emerge from this cell. The next cell, cell' 13, is arranged to have its entrance end at the same level as the exitend of the cell 12. From this point, the

wardly. The portions'of the wires that extend from the bottom of the roll 28-to the top of the roll 29 are perfectly straight, with a slight upward inclination from right to left as viewedin Fig. 1. Similarly, the path of the wires between each of the other rolls is straight. As a result of the alternate opposite inclination of successive straight portions of the path of the wires, their path as a whole is a zigzag.

Each straight portion of the zigzag path of the wires -10 travels parallel to one of the anodically charged plates 18-18 and perpendicular to the end walls of the cellin which this plate lies, so that the wires remain equidistantly spaced from the anodes as they progress through the series of cells submerged in the electrolyte. The moving wires are neither positively rotated nor are they prevented from rotating, but it will be observed in practice that they tend naturally to rotate and oscillate as they pass through different portions of the series of cells. Perhaps this is because even slight variations in the tstraightnessor the longitudinal, tension of a round wire may cause the wire to creep up the walls of a groove on. a contact roll. Although the anode plates 18-18 are located on only one side of the path of the wires, the natural rotation and oscillation of the wires causes all sides of the wires to face the cathode plates for about the same length of time.' As a result, when wires are advanced through a series of cells of sufi'icient length for this tendency to rotate and oscillate to manifest itself, it is not necessary to surround the wires with anodic plates to insure that all surfaces of the wires will be equidistantly spaced from the anodes.

I Theuniform staggering of the elevation of therolls is so'arranged that successive rolls are positioned equal distances alternately aboveand below the advancing wires 10-10. In order to achieve the zigzag pattern of the passage of the wires through the entire series of cells, the bottomsof 'all of'the upper rolls protrude equal disstances slightly below the horizontal plane in which all of the tops of the bottom rolls lie. In following its zigzag motion, each wire is bent slightly around each roll so as to provide an elongated, curved area of contact, :instead of a tangential contact at one point on the periphery of a roll. As the wires bend around the rolls, contact is made withlpressure against the rolls, thereby insuring that the wires can be positively driven by the rolls while making good electrical contact therewith.

It is to .be noted that in each instance the higher ends of adjacent cells are located on opposite sides of one of the lower contact rolls. The ,upper contact .rolls are l ayspcsitionedin he air space betw en the ower-ends of adjac n cells, audit is at suchl wers nds h ttlie electrolyte is introduced into ,the cells. The distributors 2.1-2.1: i e t th fl w f electrolyte p rds f o th lower ends towardthe higher ends of the cells. This arrangement'insuresbetter distribution of the electrolyte, by preventing the electrolyte from concentrating in the lower ends of the cells and overflowing from the lower ends only. Thus, some of the electrolyte may overflow from both ends of each cell.

It is distinctly advantageous to have short individual ll in' r s epara ed by ir sp ces ith the c thod ically charged contact rolls located in such air spaces, instead of having one continuous, long cell. Obviously, if nonconductive guide rolls were submerged in the electrolyte within a single cell having one contact. roll at each end and a length equivalent to that of the series of cells provided with many contact rolls, it would be necessary for the fewer. contactrolls of the single long cell to carry a correspondingly heavier current load to prm duce the same amount of plating. This wouldvresul-t in making the current density at the surface of the wires undesirably high in the vicinity of the contact rolls of the single long cell. Although the average current density in the two systems might remain the same, the distribution of the current density is less uniform when fewer contact rolls are utilized. In the manufacture of a copper-clad steel electrical conductor, the current density at all points along the wire must be carefully controlled, because the current density may critically afiect the crystalline pattern and density of the copper deposit. The nature and density of the copper deposit have an important bearing on the electrical conductivity and the durability of the completed electrical conductor.

In one practical embodiment of the invention, a horizontal line drawn tangent to the bottoms of the upper rolls was about 1 /2 inches below a horizontal line drawn tangent to the tops of the lower rolls. Allowing for the depth of the grooves on the rolls, the moving wires change their elevation 1% inches alternately upwardly and downwardly, each time they advance from one contact roll to the next successive roll. In this embodiment of the invention- 58 cells were used, having an average length of about 34 inches each, the distance through the air space between adjacent cells was about 14 inches, and each cell was about 48 inches in width. Twentyfive moving wires were successfully electroplated simultaneously by this system.

The above-described apparatus is simple in construction and in operation, and it may be readily disassem- The labor and expense in-- plane in which all of the cells have one end mounted,.

means for introducing electrolyte into the lower ends of the cells and for directing the flow of electrolyte towards the upper-ends of the cells, a plurality of anodically charged plates positioned so as to be immersed in the electrolyte parallel to and extending along the bottoms of the cells, a plurality of cathodically charged, positivelydriven rolls mounted rotatably between the cells for electrically contacting and guiding the moving wires, adjacent cells having only one of the rolls-mounted between them and successive rolls being positioned alternately above and below the path of the wires contacted so that the wires pass through the cells parallel to the anodes, and let. m ns at b t nds o the ell fo d chargi the. electrolyte therefrom- 2=An appera us fcr e. eet cnlatingv m ingwi c hich prises. a se ies of nd idual quallyspace ls rolytic ll a ign d i t n em s hat a plur li y of wires may be. continuously advanced therethrough in parallel, side-by-side relationship, a plurality of anodically charged plates positioned so as to be immersed in the electrolyte parallel to and extending along the bottoms of the cells, successive cells being alternately inclined at equal anglesin opposite directions so that all of the cells have a lower end in one horizontal plane and an upper end in. enct cr horiz n l plan mea s for i t g c1 trolyte into the lower ends of the cells and for directing the flow of electrolyte towards the upper ends of the cells, a plurality of cathodically charged, positivelya driven contact rolls mounted rotatably between the cells and arranged so that adjacent cells have only one of the rolls mounted between them, each roll being encircled by a plurality of spaced grooves for guiding the moving wires, successive rolls being, elevated and depressed equal distances alternately above andbelow the path of the wires contacted, the rolls above the wires being mounted between the lower ends of adjacent cells and the rolls below the wires being mounted between the upper ends of adjacent cells, the bottoms of all of the upper rolls protruding equal distances slightly below the plane in which the tops of the lower rolls lie, so that wires follow a zigzag path through the series of cells parallel to the anodes, and weirs mounted at both ends of the cells for discharging the electrolyte therefrom.

3. An apparatus for electroplating moving wires, which comprises a series of individual, equally spaced, electrolytic cells aligned in tandem so that a plurality of wires may be continuously advanced therethrough in parallel, side-by-side relationship, a plurality of anodically charged plates positioned so as to be immersed in the electrolyte parallel to and extending along the bottoms of the cells, successive cells in this series being inclined at equal angles alternately in opposite directions above a horizontal plane in which all of the cells have one end mounted, means for introducing electrolyte into the lower ends of the cells and for directing the flow of electrolyte towards the upper ends of the cells, a plurality of cathodic, positively-driven, contact rolls mounted rotatably between the cells and spaced about 48 inches from one another, only one of said rolls being located between each pair of adjacent cells in the series, successive rolls being alternately elevated and depressed equal distances above and below the path of the wires, so that the wires follow a zigzag path through the series of cells and the wires change their elevation about 1% inches alternately upwardly and downwardly each time they advance from one contact roll to the next successive roll, and weirs mounted at both ends of each cell for discharging the electrolyte therefrom.

4. Apparatus for electroplating wires, which comprises a series of electrolytic cells aligned in tandem, a cathodically charged, positively-driven contact roll mounted between adjacent cells in the series, one group of alternating rolls being mounted in a first horizontal plane and the remaining group of rolls being mounted in a differenent horizontal plane so that the wires follow a zigzag path along the rolls, an anode mounted in each cell parallel to the path of the wire through the cell, means at the end of each cell near the lower end of the anode therein for introducing electrolyte into the cell and for directing the flow of electrolyte towards the upper end of the anode, and weirs at both ends of the cells for discharging the electrolyte therefrom.

References Cited in the file of this patent UNITED STATES PATENTS 1,065,090 Werth June 17, 1913 2,424,173 Huston 'July 15, 1947 2,490,055 HOE Dec. 6, 1949

Claims (1)

1. AN APPARATUS FOR ELECTROPLATING MOVING WHICH COMPRISE A SERIES OF ELECTROLYTIC CELLS ALIGNED IN TANDEM SO THAT A PLURALITY OF WIRES MAY BE CONTINUOUSLY VANCED THERETHROUGH IN PARALLEL, SIDE-BY-SIDE RELATIONSHIP, SUCCESSIVE CELLS IN THE SERIES BEING ALTERNATELY INCLINE AT EQUAL ANGLES IN OPPOSITE DIRECTIONS ABOVE A HORIZONTAL PLANE IN WHICH ALL OF THE CELLS HAVE ONE END MOUNTED, MEANS FOR INTRODUCING ELECTROLYTE INTO THE LOWER END OF THE CELLS AND FOR DIRECTING THE FLOW OF ELECTROLYTE TOWARDS THE UPPER ENDS OF THE CELLS, A PLURALITY OF ANODICALLY CHARGED PLATES POSITION SO AS TO BE IMMERSED IN THE ELECTROLYTE PARALLEL TO AND EXTENDING ALONG THE BOTTOMS OF THE CELLS, A PLURALITY OF CATHODICALLY CHARGED, POSITIVELYDRIVEN ROLLS MOUNTED ROTATABLY BETWEEN THE CELLS FOR ELECTRICALLY CONTACTING AND GUIDING THE MOVING WIRES, ADJACENT CELLS HAVING ONLY ONE OF THE ROLLS MOUNTED BETWEEN THEM AND SUCESSIVE ROLLS BEING POSITIONED ALTERNATELY ABOVE AND BELOW THE PATH OF THE WIRES CONTACTED SO THAT THE WIRES PASS THROUGH THE CELLS PARELLEL TO THE ANODES, AND OUTLET MEANS AT BOTH ENDS OF THE CELLS FOR DISCHARGING THE ELECTROLYTE THEREFROM.

Images