One ring to rule them all?

[Rufe0]

Hmmm well I've tried but I just cant get to grips with Fusion360. I tried one called LISA which was ok drawing wise but the actual FEA never worked.

As I see it the gantry and Z are like a T in cross section, which means its a simple bending calculation. I'm getting around 0.025mm deflection at 1 meter with 200x100x8 seperated 400mm center to center.

Think I'm going to have to scale down my plans though. I will have to find a cheaper alternative to what i'm looking at the moment, maybe just wait for stuff to come up on ebay. Currently I'm pricing it from Zapp Automation for ballscrew related stuff and cnc4you.co.uk for the rails/carriages.
£110 Ballscrew support fixed end
£36 Ballscrew support floating end
£88 Ballscrew
£132 Ballnut
£37 Hiwin 25 Carriage
£37 Hiwin 25 Carriage
£108 Hiwin 25 Rail
£40 Motor
£10 DIY motor driver
Thats about £600 per screw. I need 6 screws for the basic XYZ table thats £3600. +2 for the lathe tailstock £4800. +4 for the moveable bed £7200.

So now I have to decide whether it would be best to get an old bridgeport for around £2000.

[JAZZCNC]

Head East my friend.!! . . . .China is the place for ballscrews. Contact Fred Lee at BST automation on Ali express and get a quote. You'll be very pleasantly surprised. If you want higher spec ballscrews then just Ask because he sells higher spec than class 7 advertised.

He Also sells Hi-win rails much cheapper than you'll buy in UK.

Whats the £10 DIY Motor drive.? . . . . If your thinking to build your own then unless your really really really good with electronics and have full knowledge of whats required then I'd strongly urge you to forget it and buy some decent drives with the Money you'll save from Fred Lee.!!

[Rufe0]

Bloody internets been playing up for the last couple days but yeah I had a look and thats great, this will change everything. Thanks

[Rufe0]

Yeah I dunno about the controllers, I'm using an arduino and it seems promising so far, i've just got a rotary encoder in the mail today so will be testing that out soon as.

[irving2008]

Listen to Jazz on motor drivers.. nothing you can develop with an Arduino and an off the shelf motor shield will be useful. The typical Arduino motor shields are toys, good enough for a NEMA17 stepper for a 3D printer or a small robot, even the so-called high-current ones are limited in reality because they don't have big enough heat-sinks and are restricted to 24v. For the sort of machine you're contemplating to perform at any useful rate, those screws will require big NEMA23 or even 34 size steppers, and the driver will need to deliver phase currents of 4 - 6A @ 60-80V
.
Plus an off-the-shelf stepper driver has complex algorithms for anti-stall, anti-resonance, fault-alarms, etc. You won't get close to anything useable developing your own software or using open-source stuff for several months if not years of development...

[Rufe0]

Bah Fred can only do C5 ballscrews upto 1m long. Says he can do C7 longer but I think its probably worth paying abit extra.

[dodgygeeza]

Bah Fred can only do C5 ballscrews upto 1m long. Says he can do C7 longer but I think its probably worth paying abit extra.

You can pick up C5 and C3 screws up in the UK.
I know that Zapp have C5 screws.

[JAZZCNC]

Bah Fred can only do C5 ballscrews upto 1m long. Says he can do C7 longer but I think its probably worth paying abit extra.

What machine are these going on.! . . Router or Mill.?

[Jonathan]

Bah Fred can only do C5 ballscrews upto 1m long. Says he can do C7 longer but I think its probably worth paying abit extra.

If you compare the errors due to the screw grade to other errors in the system (e.g. due to the ballscrew and associated stiffness's), your conclusion will likely change.