Dave Mucha wrote:
>Hi Kurt,
>
>I noticed you posts on the Yahoo group Electronics-101 and was
>wondering just how far you were able to get ?
>
>Did you make the power supply from Garden of EDM ?
>
>I know many people have discussed it and some have said it was too
>complex, but I don't know anyone that actually made the circuit (and
>admited it)
>
>I am fastenated by EDM and made a simple RC type. It took so long to
>cut, I only use it as a last restort. Much too slow for PCB work.
>
>Dave
>
>
>
>
>
Hi Dave,
I've been hacking around with the PCB EDM idea for a little more than a
year. I initially used salvaged printer parts in the hope that I could
simplify the software and "print" the PCB. Using PCL commands to
"print" or burn one dot on the board at a time works, but is hideously
slow. Using a plotter also adds complications in area of the pulse
return path. I have had success lately using a gantry style machine
with raster scan software. I can burn a 8.5 inch by 11 inch single
sided board in under 45 minutes. Still slow but good enough for
prototyping.
I have been using the latest update of "Garden of EDM" without problems,
but it is over powered for PCB work and I am in the process of a
redesign using Mosfets instead of IGBTs and a PIC for control
The RC or relaxation systems are way too slow and too hard to control
for gap voltage. I'm working on a PIC system that will use voltage
feedback to control a stepper/leadscrew to maintain the gap.
My current system uses A3967SLBs for stepper drivers ($3.14 per axis! )
and a LPC2138 for a system controller. The ARM chip takes a JPEG image
from a scanner or CAD program and outputs the correct pulses to burn
the image onto a PCB one line at a time. The resolution is determined
by the x-axis increment in the gantry movement.
I'm working on a new design that I think will be "ready for prime time"
or at least publication on the Web! It will use the A3967SLBs for the
steppers, a PIC for EDM pulser and an old PC for system control ( ala
EMC ) so that anyone wishing to work with the system won't be tied to
the Forth programming language that I am now using. I'm thinking of
something along the lines of a hardware version of a Sourceforge project
8-) .
At this moment I'm looking at digital cameras in order to put some
pictures in the Photos section of Homebuilt_PCBs.
Further details to follow ( when I get a handle on photography :-) ! )
--
Curtis W Richards
--
"The natural progress of things is for liberty
to yield and government to gain ground."
--Thomas Jefferson