First CNC - Initial Design Phase

So, I've been researching for a while now. I've thought about buying an off the shelf machine (CNCRouterParts or similar) but decided I couldn't really find something that fit what I wanted without too many compromises. Plus I'd lose the fun (and challenges) of designing and building my own machine. I'm currently an engineering student, and really enjoy designing, building and solving challenges.

I wanted something that had a large enough cut area to cut plywood sheets for model building as well as moulds and foam inserts for pelican cases. I also wanted to be able to machine aluminium, but I know that I'm accepting some compromise in the ability to cut aluminium given the size of the machine. I'm planning for the machine to sit on a table, which I intend to make out of welded steel, but since I currently don't know how to weld that's not a certainty, and it could end up being a solid wooden table. Either way I want the machine to be rigid enough on it's own not to have to rely on the table for extra strength.

I watched @routercnc's build on YouTube and his design served as much of the inspiration for this design. The design currently has a base made from 80x80mm heavy aluminium profile, with 100x100x5mm steel SHS to support the x-axis rails. The 45 degree bracing is 40x40mm heavy aluminium profile, and the t-slot table is 20mm thick and comes from the same company as the rest of the profile (item, there's a local distributor in Australia I have a quote from).

I'm looking at getting a 2.2kW 30000rpm spindle with ATC from Jainken (JGL-80/2.2R30-20) and ClearPath servos. And the current plan is to use 20mm Hiwin linear rails, but haven't chosen any ballscrews yet. The overall dimensions may change slightly as I work out how much cutting area exactly I lose at each end of the axes, but they're close to the size I want.

Any feedback would be great as this is my first build.

Thanks in advance,

Kieran

Looking good so far. Glad my build helped and inspired you.
Do you need to end feed sheets into the machine? If so the 45deg braces in the corners of the open end - one end could be deleted and a single horizontal connection made between the upper steel sections instead. Stiffness would still be good be access improved. Depends how you want to use it.
Also will you drop long bolts through the steel upper section as per my build? I made custom thread inserts which ran in the lower extrusion for the bolts to go into. If this is your first machine can you make these?
Also this needs clearance holes in the upper section for the bolt heads to drop through so draw these in to make sure they miss the rail fixings.
Good luck with it Kieran !

I don’t specifically have a need to end feed sheets in at the moment, but it’s probably a good idea to cater for it if it doesn’t impact the stiffness.
Regarding attaching the steel, I considered long bolts but I’m thinking of using these fasteners with the t-slot nut removed and screwed directly into a tapped hole in the bottom of the steel.
Attachment 25697