Homebrew PCBs

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

On Sat, 09 Jul 2005 01:05:09 +0200, Curtis Richards <cwrxr@...>  
wrote:

>
> 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  ! )
>


Curt,

I'm still most interested in the operating parameters you run the eden EDM  
supply with.
(voltage_PWM, current, use the boost or not use the boost).

thanks

ST