This is my first post and I am new to cnc routers so please bear with me if my
questions appear stupid. I am considering either building a router or buying one of the entry level machines. I have been in the metal fabricating business
for many years so the mechanical part of building one would not be a problem but the electrical end worries me. I have no electrical appitude. Now for the
questions. I have a Epilog Laser engraver that uses regular ball bearings
running on a semi-square rod that appears very precise ( at least a thousand or two), so after reading many treads it appears this method is low end?
Also with the laser anything I do or import into Coreldraw is simply sent to a
printer driver and the laser does it exactly. I suppose the print driver is a
controller, a g code converter and everything else. It just seems so simple
whereas with a cnc router these issues are individual components of the
system. Also I know the laser uses a servo system so could this be somewhat responsible for its extreme precision? Should I consider a servo
based cnc router? Again please excuse my ignorance on these matters
and thanks. Pat Dillon
.

A lot of routers built here use regular bearings, and yes, it is low end. It works great for the laser because there are no cutting forces with the laser. But, even though it is a "low end" approach, it can work very well on a small router. Virtually all the homebuilt routers here use a derivative of that sysem, unless they found something better on Ebay.

You can export any vector drawing from Corel as a .dxf, and convert it to G-code.

Servos are not necessarily any more precise than steppers. And most wouldn't consider .001-.002 extreme precision.

A stepper usually has 200 steps per revolution. Multiply 200 by your leadscre turns per inch to get your resolution. If you use a 10 turn per inch screw, you'll get 2000 steps per inch, or .0005 resolution per step. The question is, can you build a machine accurate enough to move in .0005 steps? Or straight to within .0005? Probaly not. Where servos excel is if you want to go really fast, or need a lot of power.