Having operated a EDM for over 13 years, its my experience that this won't work. A EDM doesn't work in this way. First the material to be eroded has to be metallic, which paint isn't. Second, for every amount of metal removed from the fork piece around 25% of that amount is removed from the electrode/needle. Third, the EDM is a slow process compared to etching.
Many people have suggested EDM over the years for making a PCB, but not been successful. Many did not understand the EDM process.
cary
--- On Wed, 1/5/11, Jeff <jeff.heiss@...> wrote:
From: Jeff <jeff.heiss@...>
Subject: [Homebrew_PCBs] Electrical Discharge Machining plus painted board plus CNC x-y table
To: Homebrew_PCBs@yahoogroups.com
Date: Wednesday, January 5, 2011, 2:17 AM
I have an idea for making boards using Electrical Discharge Machining (EDM) that I would like to bounce off you guys.
The idea is to use a needle on a CNC x-y table (picture pen plotter with the pen replaced with the needle). The needle hovers just above the copper board a few thousandths, maybe .003" – .006". Paint the copper with automotive spray paint. Apply a high-voltage/high-current to the needle and ground the board. The spark between the needle and copper will burn and evaporate away the paint. The board could be submerged in oil or some dielectric to keep oxygen out. The artwork drawn would be like that of a milled board where the copper around the traces is removed or all copper could be removed with multiple back and forth scans over the whole board.
What do you guys think? Would acceptable trace spacing and widths be achievable?
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