Frank from manchester

[JAZZCNC]

This has led me to think about building a CNC router.

Run Frank run for the Hill's before the dreaded CNC curse bites you properly. . .Lol

Welcome

I was thinking of using Aluminium extrusions as I am unfamiliar with welding and do not own a welder, so steel is not an option. It seems pretty easy to assemble a frame and has the advantage of being fairly easy to drill and tap.

Ok understand but you'll build much cheaper machine using steel. It's the hidden things like T-nuts and connectors etc that make it expensive, they can cost nearly much has the profile.
Also don't be fooled into thinking profile is easy to drill or tap has it's not. I've broke more taps in profile than I have in steel has it's structure makes drilling and tapping awkward.

This build will be done over the course of the next year or so, as money is tight and I will have to buy things in dribs and drabs. I intend to build the frame first and then worry about electronics later.

Wise choice and try to Budget for Digital drives they are worth the Money.

Two things i have loosely decided upon are the fact that it will have two stepping motors on the y axis synced through software rather than timing belts and i will use supported rails and bearings for linear motion on all axis. I am also planning on using ballscrews, but am a bit lost on the details and sizes I would need to have working dimensions Of 1220x1220 (half a sheet of plywood).

Well it's standard stuff really for your needs. Either 16mm or 20mm Dia and 10mm pitch ball-screws, Personally at this length I'd go with 20mm. Somebody is going to come along and say 16mm because of lower Inertia of screw but take no notice has it's benefit is minimal and reducing whip is prime concern at this length. You'll have more than enough speed and Acceleration for cutting wood with 20mm screws.

Length's etc then fire up solid works get designing and your model will show that based on machine design.

One question to kick things off, I notice alot of people use Mach3. I am used to using Artcam, is this rubbish or is it just as good?

Ok common miss-under standing here.!! Mach3 is just Control software and it's Only function is control the machine. It watches input and outputs for things like limit switches, E-stop etc and it also controls the Motion of the machine by sending signals to the motors telling it where to go based on G-code files you create in CAM software.

Artcam is just that CAM software and the file it produces is G-code file which you load into Mach3 or any other Control software like Linux CNC.
Cam software has with it a post processing side where you select which Control software your using and it then formats the Out putted G-code file in the way your Control software like to See it.

Hope this helps and Happy building.

PS: Buy a Welder and learn a new skill it aint hard. .