Re: NEWBIE WITH PLASMA/ROUTER ??'s

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "alex" <telecomt@t...> wrote:

> Tom,
> how do you adjust the height - with a separate stepper?
> Alex

No, that's the beauty of having the Controller Software (MACH2)
involved in the THC process. My circuit measures the tip voltage and
gives a logic UP or DOWN signal to a parallel port pin. The software
sees the signal and adjusts the Z axis up or down at a defined
feedrate. you need a three axis machine but there are reasons to do
that anyway. The advantage is that then the software "knows" where
the head is at all times and when you get ready to retract the head,
move and lower it again to pierce height, it can all be done easily
in G-code. A really nice benefit is that the torch can be tapped to
provide an "Arc Good" signal (TORCH ON input in MACH2) and the
program will not start XY movement until it gets the signal. It
prevents a lot of missed cuts.

The circuit is one IC, some opto isolators, a few transistors, and
some passive components. Right now all that is available is a
schematic but soon there will be complete instructions and for non-
commercial use (you can build one for yourself but not to resell)
artwork for a doublesided PC board(s). If the interest is there I
can make kits of PC board and parts available.

I have been using mine now in semi-production for several weeks and
it works great.