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PLATING RACK FOR HOLDING PRINTED WIRING BOARDS (PWB) IN PLATING TANKS

IP.com Disclosure Number: IPCOM000025609D
Original Publication Date: 1986-Aug-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 198K

Publishing Venue

Xerox Disclosure Journal

Abstract

In the past, plating racks have been made of metal and covered with a rubber material to prevent them from becoming plated while immersed in a plating bath solution for plating printed circuit boards. Such racks are used for supporting, e,g. electrographic head panels comprising printed wiring boards (PWB), for immersion into a plating bath solution. These frames must be made of conductive material, usually stainless steel, and be in electrical contact with the panels to be plated to function as a cathode in the bath solution. The problem is that the rubber coating deteriorates quickly and, soon, plating deposits build up on the exposed metal surfaces of the rack, This is not only undesirable from the standpoint of waste of plating material but also increases the total surface area actually plated in the bath thereby affecting the plating rate of' the bath and the overall uniformity of desired plating thickness on the panel Thus, there must be a way of stopping this deterioration so as not to effect the plating rate, as it is not practical nor desirable to attempt to monitor and change the plating material present in the bath solution to meet changing conditions in the amount of exposed metal surface that might being plated because of a deteriorating support rack.

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Page 1 of 4

KEROX DISCLOSURE JOURNAL

PLATING RACK FOR HOLDING PRINTED WIRING BOARDS (PWB) IN PLATING TANKS
Derrick
A. Kendrick
Stephen Deming

Proposed Classification U S. C1.401/48
Int. CI. A46b 11/00

Volume 11 Number 4 July/August 1986 203

[This page contains 1 picture or other non-text object]

Page 2 of 4

PLATING RACE FOR HOLDING PRINTED WIRING BOARDS (PWB) IN PLATING TANKS (Cont'd)

204

32.

f.5

32-

  XEROX DISCLOSURE JOURNAL Volume 11 Number 4 July/August 1986

[This page contains 1 picture or other non-text object]

Page 3 of 4

PLATING RACX FOR HOLDING PRINTED WIRING BOARDS (PWB) IN PLATING TANKS (Cont'd)

In the past, plating racks have been made of metal and covered with a rubber material to prevent them from becoming plated while immersed in a plating bath solution for plating printed circuit boards. Such racks are used for supporting, e,g. electrographic head panels comprising printed wiring boards (PWB), for immersion into a plating bath solution. These frames must be made of conductive material, usually stainless steel, and be in electrical contact with the panels to be plated to function as a cathode in the bath solution. The problem is that the rubber coating deteriorates quickly and, soon, plating deposits build up on the exposed metal surfaces of the rack, This is not only undesirable from the standpoint of waste of plating material but also increases the total surface area actually plated in the bath thereby affecting the plating rate of' the bath and the overall uniformity of desired plating thickness on the panel Thus, there must be a way of stopping this deterioration so as not to effect the plating rate, as it is not practical nor desirable to attempt to monitor and change the plating material present in the bath solution to meet changing conditions in the amount of exposed metal surface that might being plated because of a deteriorating support rack.

We have designed a new rack 1Q shown in Figs. 1 and 2 which comprises horizontal bars 12, 14, and 16 connected to vertical bars 18, 20, 22, and 24 Except for bars 14 and 16, these bars are made of copper and are hermetically sealed within fiberglass extrusions. Bars 14 and 16 and all other parts of rack 10 not requiring electrical conductivity are made of fiberglass or polypropylene. A cross section of a vertical copper bar is circular and is shown at 13 in Fig 3 The cross section of the fiberglass extrusion is a square and is shown at 15 in Fig. 3

At the tops of bars 18-20 where they are electrically connected to fiberglass covered horizontal copper bar 12, a metal rivet or lug similar to that shown in Fig. 3, is used to connect these bar tops to bar 12 The exposed openings are covered with fiberglass to prevent exposure to the plating solution At the top of vertical bars 18 and 24 are metal hook members 26 electrically connected to these bars for supporting rack 10 during its insertion into a plating bath solution However, members 26 do not themselves become immersed in the soluti...