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Subject: Re: [Homebrew_PCBs] PCB EDM MILL Initial Tests

From: roger lucas <ralucas4277@...>
Date: 2006-05-02

Hi Stefan,

I know that it should have worked in theory, but I was
surprised at how well it actually turned out.

I tried with tinned copper wire and a tinned steel
sewing needle (purloined from my wife's needlework
box), essentially the wear was about the same for
both. The eroded pixel diameter is directly related to
the electrode dia, as the sewing needle eroded the
pixel became larger.
I need to try to obtain some half hard or hard 10 mil
brass wire for the next trial.

The setting of the spark parameters before sparking is
essentially to eliminate the uncertainty of whether
pixels have been fully eroded or not, especially where
electrode wear is high. I might just try some broken
carbide drill bits, the tungsten might resist erosion
better, trouble is carbide only goes to 0.5mm dia.

Will post some sample photos after next revision and
trials.

Roger

--- Stefan Trethan <stefan_trethan@...> wrote:

> Good to hear you got such good results.
>
> I don't have any specific concerns why it would not
> work, never had after
> some manual tests with a simple power supply.
>
> But i don't currently have the time to build a CNC,
> although i have most
> components set aside for a while now.
>
> The electrode erosion thing was discussed back then,
> if i remember
> correctly the thinking was that one would advance
> the electrode until a
> spark of the correct voltage is occuring. One would
> need to decide if the
> energy was sufficient to blast out the pixel or if
> it must be re-done.
> But your approach seems a good idea also.
>
> Keep us updated, i definitely plan to build the CNC
> but it will be months
> for sure. If i use it for drilling of inkjet printed
> PCBs or if EDM will
> be an option is to be seen.
>
> what material is your electrode wire made of?
>
> ST
>
>
> On Tue, 02 May 2006 18:07:19 +0200, roger lucas
> <ralucas4277@...>
> wrote:
>
> > Well, I finally motivated myself this holiday
> weekend






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