Re: Wire ECM

--- In CAD_CAM_EDM_DRO@yahoogroups.com, juan gelt <juangelt@...> wrote:

>
> 1000A/sq in is needed to remove a bulk of material
> quickly. But just as with a taig, one does things on a
> smaller scale with hobbyist equipment.
> ECM is just plain slow but there is little that can
> rival its precision.
> i once drew a tube of an eyedropper so fine that
> gravity was overcome by the capillary- with this- i
> was able to drill a tiny hole in a copper penny inside
> of the loop of the 9 on the date. it took overnight
> cuz of no outrageuos current densities and the actual
> cathode was way up in the eyedropper. But say you just
> LIKE having tiny holes in copper...
> Therefore i will offer ENCOURAGEMENT to anyone wishing
> to experiment with it. it is tremendously easy to do
> exceedingly fine etching and marking on things lasers
> will have trouble touching and for which you won't
> easily find the tiny tools available any other way.
> do it and find out. :) THAT's where the fun is! ECM is
> probably the only way a hobbyist can actually put
> angels on pinheads.
>

Excellent stuff, I love the method of using a wire inside an insulated
tube, it saves all the hastle of trying to insulate and electrode etc
and you can let gravity VS flush pressure maintain the gap if you want.

The other thing is that if you are looking at small electrodes the
number of amps to get 1000A/in^2 does not have to be that great. And
if you just want a hole you don't need such high current densities anyway.

There has been some discussion on the DIY_CNC forum about pumps for
coolants which led me to find some small hydraulic pumps that operate
from 12/24v that are use for tail lifts etc, could at least provide a
decent flushing velocity on larger items when the gap is small.

In my experiments I actually found ECM to be quite fast and that was
with a current limited PSU (max 1.5A, based on LM317) it depends what
you are doing I suppose and how fast, fast is to you.

I would say tiny holes in a penny (which could have been tool steel)
with no other equipment than a PSU and some salty water at one hole
per night is actually fast. Certainly compared to not being able to
do it at all.

Graham