Re: foam cutting current ?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude"
<dave_mucha@...> wrote:

>
> Hi all,
>
> Is there a formula to help select the proper voltage and current for a
> foam cutter ?
>
> Any special wire ?
>
> Dave
>

I don't know of any formulas but power disipated is I^2.R and the R
will be a function of temperature itself so it might be a bit
complicated. I suspect it is a rule of thumb situation.

How long a wire do you need for cutting? A review of RC websites
might give you an idea of the currents, its not more than a few amps.
, lots of people seem to use 12v transformers driven from dimmers. A
current regulated supply might be better.

The best wire is nichrome, it has a high resistance and is very
strong. I do manual cutting with a 0.25mm wire which is rather thin
but reduces my "recast layer" meaning there is no melted surface on
the foam. In CNC I think they tend to use the wire in a non contact
mode so they always have this melted on layer which is fine if weight
is not the issue and it can give a nice finish.

Graham