Importance

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Abstract

Printed circuit boards can be continuously electroplated by passing them through a pair of rollers (7) forming cathodic rollers, which are spring-pressed towards each other, the rollers being driven, for example at the circumferential speed of about 1/2 meter per minute. The rollers form a transport arrangement for the printed circuit board, while providing electrical connection to conductive tracks thereon. Closely downstream of the cathodic rollers are a pair of anodic rollers, made, for example, of titanium with a covering of platinum or iridium, over which a felt sleeve is placed, on which felt sleeve an electrolyte, including sulfuric acid and copper is sprayed. The anodic rollers, connected to a positive terminal, are spaced from the surface of the printed circuit board to leave a surface gap between the rollers and the printed circuit board of about 0.1 mm. Copper is electrolytically deposited, for example, at the current density of about 15 A/dm.sup.2, which is about six times of the density of immersion bath galvanizing, thus permitting deposition of about 32 micrometers copper in 10 minutes rather than 60 minutes in an immersion bath. A plurality of cathodic roller pairs (7) and anodic roller pairs (8) are combined in a single housing to form a module, for example of 10 pairs each, requiring for ten modules 7 meters of length of plane floor space for continuous processing.

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First Claim