Process for improving the coating of electrolytically treated work pieces, and arrngement for carrying out the process
US5558757A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 29, 1994 |
| Grant date | Sep 24, 1996 |
| Priority date | — |
| Expiry date | Jun 29, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K3/241
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The invention starts with a process for improving the electrolytic coating of work pieces (3) that are arranged one after the other as a row at a distance from each other on cathode rails (1) or on cathode frames in a bath, whereby the cathode treatment current (I) of the rail or the frames runs parallel to the direction of the above mentioned series of work pieces (3). In order to prevent the large differences in layer thickness in the edge area of adjacent work pieces, e.g. circuit boards, that occurs with the state of the art, without having to go to disadvantageous effort to decrease the voltage drop in the cathode rail or a corresponding frame carrier rod (63), it is provided that the direction of the cathode current flow (I) at least in the cathode rail (1) or the cathode frame carrier rod (63) is changed at least once during a treatment process. This may be done by initially supplying current to a first end of the cathode rail or carrier rod and then switching the current supply location to the opposite end. The invention also relates to an arrangement to carry out this process. Switching may be accomplished by electromechanical reversing switches or electronic d.c. current …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.