Homebrew PCBs

On Wed, 24 Aug 2005 14:16:51 +0200, ralucas4277 <ralucas4277@...>  
wrote:

> I am therefore going to dump the tin resist approach and concentrate
> on a machine similar to Carl's philosophy.
> First is to build the Garden od EDM power supply and do some tests on
> hole size and quality with varying parameters.
> If anyone has any suggestions on how to replace the IGBTs with
> MOSFETs in that design, I would appreciate any comments.
> Roger


I would not dump it, but first try the method that would result in a great  
simplification of the overall process.
If it doesn't work you can still go back.


I think you are right, a defined amount of energy, and thus a defined  
amount of abraded material might be the key to etching down to the  
laminate. What i see as a potential problem is how to figure out the ideal  
process to position the electrode. One approach could be to treat each dot  
as individual sinker EDM process, but the trouble is when you are finished  
there is solid material after the copper.
Ideally, one would be able to blast each dot with a single spark, but what  
if you were just advancing and the gap was so large you only achieved  
maybe half a proper spark. What do you do? stop and try more sparks?  
advance?

I think you might be able to use high power FETs in a very similar  
fashion, as they have similar gate characteristics.

ST