3 Axis CNC router

**JAZZCNC** · 19-01-2016

Originally Posted by routercnc

Hi Joe,
I wonder if that long unsupported run of belt would flap and vibrate around. Do you think it would be in perfect syncrony on each ballscrew? Also, a single motor would need to be more powerful than 2 singles.

Yes and No. Yes it needs a some support in the middle to stop flap. Does it keep perfect sync.? Yes it does.

Originally Posted by routercnc

On my new machine (not CSMIO) I am going with 2 motors and 2 short belts, then one long slave belt between them which mostly does nothing unless there is a problem.

Not so sure that will work has good you expect.? While in theory it will help keep screws in sync I'm not sure about the conflicts you might get if one motor starts missing steps. You'll have one motor fighting the other and because the Motors are connected directly to the screw I think you'll still get racking because the motors torque will force racking or affect the other motor and cause stalling etc.?
Also Don't see the point in taking the conflict risks when you still have the same belt setup.?

Edit: Then you have the affect of extra inertia of 4 pulleys on screws. It will affect performance.!

One thing for sure if you do this then make sure you have good drives because it will do funky things to the resonance and the drives will need to able to deal with it.!

Originally Posted by routercnc

Would CSMIO let you feed step/dir signals into 2 drives? Is that acceptable? I know you can't 'slave' home in the traditional sense with that suggestion, but with a link belt you wouldn't have to.

Bad idea with any controller but this isn't needed anyway the IP-M does allow slaving just doesn't independantly home each Axis.

Originally Posted by JoeHarris

I was going to up the motor to a nema 34 12nm beast. This is a similar size belt to Dean's first machine I think? He had an idler part way along not at one end. If I get flapping I could add one in the same way. I understood that the ip-m just did not allow proper slaving...

12Nm is way to Big Joe and will affect performance. 6 or 8Nm will be more than enough. Try to find motor with lowest inductance possible and use plenty of volts.