Sorry, I'm sure this topic has come up many times, but I've searched and haven't found out anything to work out what kind of motors will work without being overkill.
I'm still working on the design (so nothing to show yet). But I plan on having a fairly standard gantry type CNC that is capable of milling PCB's and perspex (aluminium would be great but I suspect a dremel as the spindle wont handle that well and the motors needed to drive it will most likely end up costing me a fortune). As for the accuracy I want to be able to mill SMD boards 0.5mm traces if possible. Perspex, will be milling parts for various projects (mostly bodies for robots).
Unfortunatly where Im located its difficult to source reasonably priced motors, so I'll have to buy off ebay and suffer the shipping costs (around US$190+ for a Nema23 305oz-in motor if I buy locally, around that for 3x178oz-in motors including shipping from ebay).
But how do I work out roughly what kind of torque is needed in the motor to do what I want to do? I want to roughly get a minimum torque needed, add a bit onto it for safetys sake and get something with that torque and above.