Re: Help?? CNC PCB Drilling Machine - EDM a PCB

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Richard" <phrh@w...> wrote:

> List
>
> I worried about the leakages between copper lines on the
> boards 'etched' by sparking and although I found none in my

playing,

> the concerns are all valid. My guess is that a quick chemical etch
> would be a good idea, maybe after drilling, just to clean up the
> boards. It seems to me that this would be a reasonable step for
> boards made in the conventional method as well. How does one know
> before testing a wired assembly whether there may be a leak
> somewhere?
>
> I like Jon's suggestions about more careful board surface grounding
> to ensure complete connection.
>
> And Jon, I split a standard pencil to rescue a short length of

0.072"

> diameter electrode material. The electrode shows no wear from the
> sparking and other abuse subjected and shows hope. (It may be a bit
> shorter but shows no pitting).
>
> There is still much to learn and all ideas are helpful.
>Richard
>

Seems that if a decent connection could be made with a mechanical
pencil, one could use a standard 0.05" lead or an .03" fine lead.

and, thinking about coatings, it will take some experimentation, but
it seems like a normal resist would be possible and that all one
needs is a starting point. the EDM process would always find the
edge and burn the resist away.

possibly a pre-etch with a scratch awl... proof the board at the same
time.

In thinking about this, it seems that a large copper block or two
could be placed on the boards as grounding so that they could bridge
traces as the work progressed.

now if we could figure a way to 'burn' thru the boards......

Dave