by bdring » Sun Jun 26, 2011 7:38 pm
I'll work backwards from the machine to the drawing.
You can have a machine as simple as a single motorized axis. The amount the motor moves needs to be controllable in discrete increments. This is usually done with a stepper motor that moves one small step at a time or via standard motor that feeds back how far it has moved like a servo motor (not hobby servo). You need a driver to run that motor. At the home built level drivers usually accept step and direction signal regardless of the motor used. Each step is usually 1/1000 of an inch or less. You now need a controller (like an Arduino) that can turn a G-Code command like "move 1 inch" into the right number of steps. Software (like Mach3 or EMC2) using parallel port can do this or you can have a dedicated controller in the CNC machine.
You also need software to take you vector drawing (DXF, DWG) to G-Code. This is done with a CAM program like Vectric Cut2D or Mach3 LaztCAM.
It sound complicated, but you could probably have a motor spinning using free software and cheap parts for about $30.
Bart
"If you didn't build it, you will never own it."