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Producing Smooth Plated Surfaces in Recessed Areas on Circuit Panels

IP.com Disclosure Number: IPCOM000074053D
Original Publication Date: 1971-Mar-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Lubert, KJ: AUTHOR [+2]

Abstract

This method provides a smoother contact area on card tabs of encode cards. Encode cards must meet a smoothness specifications on the tabs of 0.2 mils maximum roughness. At present, the entire tab and a portion of the connecting line are Ni and Au plated over the entire surface to meet this specification.

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Producing Smooth Plated Surfaces in Recessed Areas on Circuit Panels

This method provides a smoother contact area on card tabs of encode cards. Encode cards must meet a smoothness specifications on the tabs of 0.2 mils maximum roughness. At present, the entire tab and a portion of the connecting line are Ni and Au plated over the entire surface to meet this specification.

As a specific example, it is proposed that only the 140-mil spot of the tabs be addressed such that MYLAR* strips with 140-mil holes are laminated over the tabs before plating; that the spot be electropolished, nickel-plated and then gold- plated; that thickened electrolytes be used for the electropolishing, nickel plating and gold plating solutions to take advantage of the apparent increase in brightening (decrease in micro-roughness) noted with the successive processing steps. The area of the tab becomes smoother as each step is accomplished. The process steps include: 1) Starting at the "ready for Ni plate" stage, laminate the MYLAE strip (with holes punched therein) over the chlorite treated copper tabs. 2) Electropolish the tab area enclosed by the punched holes with a viscous electrolyte. 3) Electroplate Ni from a viscous electrolyte onto the tab area within the hole areas. 4) Electroplate Au from a viscous electrolyte onto the Ni.

The above process steps utilize electrolytes thickened with a compatible gum, such as tragacanth. Viscosity of the electrolytes can be varied to suit the operat...