Comments sought on new build: A CNC Router for RC Gliders and Planes

[JAZZCNC]

I'm using RM1610 screws....main use will be plastics a bit of aluminium and possibly light cast iron work (spot facing cast iron couplings etc.) with a bit of balsa and lite ply cutting. I've got AM882's at the moment, they do up to 8.2A so a SY85STH118-6004B Nema 34 rated at 6A should be OK to drive?

Neil it's the 70-75Vdc limit of the drives that causes the problem with Nema34 motors. Larger motors need 100V+ to get decent speed out of them and that's why High power 240 Drives are best. Now with 10mm pitch screws and 75Vdc you'll get approx 8mtr/min of usable speed with a decent weight gantry. You'll possibly get higher speeds but they won't be reliable and could stall if pushed hard. That is more than enough for cutting most soft materials so again personally I'd go with single motor setup for reliabilty issues and to remove all doubt.!

That said AM882 are good drives for slaving has they have stall detect and can be used to stop system so either setup would work. You'll possibly get slightly higher rapid feeds from Twin motor setups as motors spin faster but that doesn't mean you'll get higher cutting feeds as the 34's tend to have more torque higher the RPM scale then drop off quickly.!