Re: [CAD_CAM_EDM_DRO] Future CNC man

shawnusa@... wrote:

> I plan in th near future to setup a CNC for a 3-n-1 system. I have
> not worked all the details out on the hardware side, but I was
> wanting to know what is needed from the software side to get the end
> results on the CNC machine. I'm a user of Autocad and wish to stay
> with it. What is involved in taking a Autocad file and turning it
> into a working part. I see lots of refrences to EMC for linux. Would
> files move from the NT Autocad enviroment to the Linux and is there
> some sort of file conversion?

Well, it is a lot more than a file conversion. The autocad generally is
a bunch of lines in 3-space (if you do a 3D drawing) that specify
some sort of outline of something. generally, it doesn't even tell
you what is 'material' and what is 'empty space'. Also, a CAM program
doesn't know HOW you want to do things. On a Kearney & Trecker
boring mill you would drill a 3" hole a little undersize and then take it
up to size in one pass with a big boring bar. On a Sherline, you would
use a 1/4" end mill, perhaps, and spiral out from the center to make the
hole a little at a time. So, the CAM needs to know what tools you have
(ie. drill bit or end mill size, etc.) before it can even think of creating
the
toolpath. Also, will you cut a pocket all in one pass, or will you have to
step down in Z, carving it out a little at a time? All these things have
to be answered for the CAM program to know how to proceed.

So, you need to get a CAM program. There are some add-on CAM
programs available for acad. Some are probably good, and may also
be expensive. I use Bobcad/CAM, an integrated package that does
the CAD as well as the CAM. I didn't have a mechanical CAD program
already, and wanted an integrated one, as I didn't want to fight DXF
file compatibility problems. It works, but the CAD may not be the best.

After the CAM package (with your guidance) has made the CNC
program, you can then transfer it by floppy or network from the Windows
system to the Linux system. (It may be possible to run the Windows
software UNDER Linux with a Windows emulator or virtual PC
software.)

> Anyway I'm trying to visualize what's
> involved on the software side of things. LIke I said though I would
> like to use my Autocad files.
>
> Thanks for answering my newbie questions. I hope to be in the CNC
> world soon. Looks to cool not to do.

Jon