DIY 6040 CNC - advice required!

[Pointy]

Hi guys,

I am thinking of building myself a bigger CNC. I currently have a cheapo 3020, which has served me well, but it's time for something a little bigger. I initially looked at kits and was thinking of building an Openbuilds machine. The main reason being my lack of a machine shop to make custom parts, and I almost wanted something I could bolt together. As Jazz had done a stellar job on making me a custom panel, I emailed him about some custom plates. Being the wise owl that he is, he knew exactly what they were for and kindly steered me away from that direction. I am really glad he did, because when I costed everything, I realised that for the cost of the wheels, spacers, bearings and leadscrews, I could get some ballscrews and linear rails.

With that option out the window, it meant I have 3 options...

1. Make the current machine bigger.
2. Buy a prebuilt 6040 frame
3. Design and scratch build something.

Option 1 would be the cheapest option, as I would probably just have to buy rails and a leadscrew for a longer Y axis, and re-use the current Y axis parts for a wider X axis. (It wouldn't be a 6040, but more like 6030 and would still have the unsupported X rails)

Option 2 is the easiest, but least fun and would end up with the same unsupported X axis rails.

So that leaves option 3, and being on a really tight budget makes it a bit more challenging. I hope I can re-use the electronics and motors from the old machine for starters. I have no idea what rating the motors are as they are unbranded. I only have the 3 cheapo stepper drivers that came with the original machine and they are rated at 2.5A.

So the first couple questions before I dive into design are...

Bearing in mind I would like to be able to do some light aluminium work, what the minimum size profile & plate thickness I can get away with for a 6040 size build with a frame design like this?



Would Hiwin 15mm rails be good enough?

Regards,

Les