GB1088688A - Apparatus for electrolytically plating a strand of material - Google Patents

Abstract

In an apparatus for plating a strand, e.g. to form high frequency coaxial cable, in which said strand is passed from a supply means 14, via a guide means 16, through a series of reagent tubes 18 arranged in an in-line relationship longitudinally, each of said reagent tubes being inclined at a small angle to the horizontal and being provided with a reagent inlet 19 at the upper end thereof, and through an electroless plating means "X" to an electrolytic plating means, the strand to be plated passes from the guide means 16 to the electrolytic plating means whilst contacting air and reagent only. The electrolytic plating means shown comprises a plating tank 32, a plurality of <PICT:1088688/C6-C7/1> <PICT:1088688/C6-C7/2> drive rollers 22 mounted on a frame 30 mounted immediately above the tank 32 and a plurality of idler rollers 34, 34a, 34b mounted within the tank as shown, the idler roller 34a being positioned above 1/3 of the way down from the top of the tank, the rollers 34b about half-way down and the rollers 34 adjacent the bottom of the tank. Voltages impressed on the drive rollers 22 vary from 15 volts on the first roller to 2 volts upon the further rollers. Vertical counter electrodes 38 are positioned beneath the rollers 22. The drive rollers are each driven by a separate worm gear mechanism. The drive rollers are formed with three adjacent grooves (26) for each strand, to lengthen the life of the roller Fig. 4 (not shown). Prior to passage through the electrolytic bath, e.g. during passage through the reagent tubes and baths X and Y, the strand is etched to render it hydrophilic; rinsed; subjected to a sensitizing treatment, e.g. with stannous chloride; rinsed; has a catalytic film deposited thereon, e.g. palladium chloride or a silver salt; is rinsed and is passed through an electroless copper deposition bath comprising a solution of copper sulphate and formaldehyde and a solution of sodium carbonate, sodium hydroxide and Rochelle salts, the two solutions being mixed immediately prior to use, and is thereafter passed through a water bath "Y". After passage through the electrolytic bath, the strand is passed through a water rinse station (42) and an anti-tarnish station (44), to a take-up reel (46) Fig.1 c (not shown).