Software for CNC routing
Design. For design I use Autocad, the engineer's concubine.
Designs are made from scratch, or adapting existing dxf files to suit
and by scanning plans from magazines. Scanning works nicely, but dont
think that just cause a computer scans in a picture you'll instantly
have a set of drawings. Its nearly as tedious to convert the bitmap of
a scanned image into a CAD file as it is to start from scratch.
G-codes. Once dxf files are made they must be converted to
files containing g-codes. An example of g-code is the
following. Comments are in parentheses.
G90 (make parameters absolute)
G20 (make parameters inch units)
G53 (set to machine coordinates)
F10 (set feed rate to 10 in/min)
G01 (linear interpolation)
M07 (cutting tool ON)
G00 Z0.500000 (Machine move up to .5 of an inch)
G00 X0.979956 Y4.350535 (Machine move over to x-y position)
etc....
Here is a summary of gcode commands. If they dont make sense
that's okay they dont have to. With good software to create your
g-code files you rarely have to go in and actually -look- at them.
An example dxf file: 11.dxf
Example g-code file derived from that dxf: 11.txt
Making the transformation from dxf to gcodes is no problem if you are
willing to spend some money. I went with BobCad which is around $500.
See http://www.bobcadcam.com/ BobCad is pretty good. I could
live without the ridiculous amount of junky emails -and- junk land
mail they send. When you are evaluating software find out how many
mouse clicks are required to make g-codes. Doing a lot of pointing and
clicking is tedious. Also look for features like cutter compensation,
modeling of your g-codes, and the ability to track cutting tool moves
with lines of the g-code file. I rate BobCad a C+ in most of those
categories.
Cost. To be fair, the user market for g-code making software is
tiny. It is unimaginable that the cost of of development required for
a good window's based program would compare well to the amount the
user market would return for that effort. As you will quickly discover
with a web search on the terms "software gcodes CNC", quality
industrial grade programs are extremely expensive. Consider yourself
lucky if you get away with functional software that costs less than
$1,000.
G-code software sources.
Looks like a possible alternative: http://www.millwizard.com/.
I am evaluating StlWork: http://www.stlwork.com/
not recommended, this is just a toy:
http://members.aol.com/andrewc119/index.htm
tres pricey: http://www.mastercam.com/mainFrame4.htm
link pages:
This guy has a lot of useful information:
http://www.computersculpture.com/Computer_resources.html
Others:
http://www.metalworking.com/shareware.html
http://www.wokingham.demon.co.uk/links/links.htm
http://www.wokingham.demon.co.uk/software/software.htm
try your luck:
http://www.super-tech.com/
http://www.deskam.com/
http://www.metacut.com/home/MainMenu/Home.htm
http://www.sub-soft.com/
G-code motor drivers. Once the g-codes are made you need
software to drive your motors from your parallel port. The software I
recommend for this is cncpro of Yeager Automation fame. It
is not necessary to have software with a whole lot of features for
this part of the process so dont get drawn into buy something really
expensive.
Platform. Use your favorite machine to make CAD files and to
convert those files to gcodes. After creating g-code files use a
separate computer to that reads the g-code and drive your
table. Imagine a computer that is located near your cnc table and is
continuously breathing balsa dust into its cooling fan. This should
just be an old beat up box that will just be running DOS and cncpro.