PDA

View Full Version : DIY 6040 CNC - advice required!



Pointy
11-09-2016, 10:30 AM
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 (http://www.mycncuk.com/threads/7193-CNC-3020-Enclosure-Upgrade?p=56725#post56725), 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...


Make the current machine bigger.
Buy a prebuilt 6040 frame (http://www.ebay.co.uk/itm/EU-Stock-6040-CNC-Router-Milling-Engraving-Machine-Frame-Kit-with-80mm-Clamp-/112129620440?hash=item1a1b7239d8:g:P2EAAOSwQaJXTUP k)
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 (https://tr.aliexpress.com/item/2-5A-stepping-motor-driver-for-mini-cnc-engraving-machine-accessories-of-cnc-router-machine/859633758.html) 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?

19171

Would Hiwin 15mm rails be good enough?

Regards,

Les

Lee Roberts
12-09-2016, 09:39 PM
80x40 for the profile
15mm for the plates

Yes to 15mm linear guideways

.Me

Pointy
14-09-2016, 12:43 PM
80x40 for the profile
15mm for the plates

Yes to 15mm linear guideways

.Me

Thanks for the reply Lee. My initial design uses 80x40 and 15mm plates, so it must have been a lucky guess.

I suppose the problem with using 80x40 is that the slot will be too big for the 15mm linear rails, without custom plates.

Regards,

Les

A_Camera
14-09-2016, 01:05 PM
Thanks for the reply Lee. My initial design uses 80x40 and 15mm plates, so it must have been a lucky guess.

I suppose the problem with using 80x40 is that the slot will be too big for the 15mm linear rails, without custom plates.

Regards,

LesIn fact, I'd use 90x45 or even larger. My current build is made up mainly of 90x45 and no regrets at all. Regarding the rails, I think it is in any case a good idea to install those on a plate, and not directly on the aluminum profiles. I am using 4mm thick aluminum pates between my (supported round) rails and the extrusions. Perhaps if I'd have flat 15mm rails I'd put steel plates between, not aluminum, but I think even aluminum is better than nothing.