Hi there!
I'm planning on building a steel base cnc mill with Igus Drylin W linear rails and a roller chain or belt drive (leadscrew for the z-axis).
I can get the linear rails for free from my university. They are the 16mm diameter version with single sided adjustable play.
The aluminum extrusions are 8020 with 45x90mm. I'm getting these for free from university as well.
The base frame is planned to be made of steel I-beams with 80x160mm 5mm thickness and some steel tubing with 40x60mm 2mm wall thickness (i have those lying around at home).
All the other parts (z-axis carriage, motor mounts) will be made of 4mm hot rolled steel.
The whole z-axis including the y-axis stepper motor will weigh around 8kg and the y and z axis together should weigh about 16-17kg.
I'm planning on driving the whole thing with four nema23 425oz stepper motors running in bipolar series mode (2.1 amps/phase) on a TB6560 based driver board (but definitely not one of those badly designed ebay ones).
It's inteded use will be routing woods (mostly really soft stuff, but also some beech) with small sections of polyurethane cast into the wood (think ski/snowboard woodcores+sidewalls).
Attached is a couple of (bad) renders of a quick sketch up I made.
What do you think of this design? Do you think it could work?
PS: the thing I'm most worried about is if the 8020 y-axis beam will be strong enough or if I should swap it for some square steel tube (weight? maybe need bigger motors?).