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Greg G. (in ) said:

| Morris Dovey said:
|
|| I've been thinking seriously about CNC conversions for mini-mill
|| (HF) and mini-lathe (Griz) for making small metal parts for the
|| woodshop. Either can be built using all new components for under
|| $2K. I have a programming background and was able to write the
|| driver software for a $200 controller card in about an hour. It's
|| /not/ rocket surgery!
|
| What program(s) do you use to generate the plot files?
| Do they produce Gerber output, or something else?

With the ShopBot, I have two approaches. The first is fairly
conventional: I make drawings in DesignCAD and export them as DXF
files. If the drawing consists of toolpaths, I can hand the DXF
directly to the SB cutting program. If the drawing consists of edges
(a more usual type of drawing) I use a program called PartWizard
(provided by ShopBot with the machine) that interactively converts
drawing to part program, which is then fed to the cutting program.

The second approach isn't so conventional. With this approach, I write
C programs that output a file of part program commands. This lets me
take advantage of all the capabilities of a general-purpose
programming language to do things not readily done within the limited
capabilities of normal part programs.

I've also hacked my cutting application to allow me to invoke and pass
command line parameters to an external program from within an
executing part program. This allows me to (interactively) generate and
execute part program code "on the fly".

The second approach "unhooks" me from the machine vendor, since I can
as easily emit g-code as the proprietary ShopBot codes.

I think more than 99.99% of executed commands are 'move' commands, so
it doesn't appear any more difficult to call a controller driver with
parameters for a tool move than to write a tool movement command with
those same parameters to a text file...

| I have considered this very thing, not only for woodworking, but for
| drilling numerous tiny, precision holes in printed circuit boards.

And if you add motor speed control and replace drill bit with a router
bit or end mill...

| Started building a small X/Y/Z drill plotter back in 92, but never
| finished it due to various moves around the country. Finished most
| of the software, but never completed the hardware. It read Gerber
| files. The cost of big stepper motors and such relegated it to the
| back burner - I was going to salvage the parts from old equipment,
| but never found a good set of adequate matching motors.

Important things have happened since then - E-Bay, Google,... :-)

|| There was a recent thread with a Dutch OP who built a CNC router
|| and
|
| I noticed that as well. Looked over some of his pages, and meant to
| reply to him, but life got in the way...

Well, I think I'd have done it differently (which just goes to show
that everybody's an art critic) but the important part is that _he_
got the job done simply and inexpensively - and he was willing to
share with the rest of the world. Once the basics are in place, one
can always make refinements. I think he merits at least an "attaboy!"

Build your machine!

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html