The ODrive works with Hall Sensors just fine. It is however using FOC.
Honestly if you could find a ESC that properly supports this motor (voltage, kV rating, current handling, etc) and just used a simple Arduino to PID control the speed it would work great. The problem I ran into was finding such an ESC. Everything out capable of handling the kV rating could not handle the voltage. Everything that could handle the voltage could not handle the kV. That is why I went with the VESC and now the ODrive.
Ran some back to back Modkita (VESC) with a 1.5kw 110v in 6061 on the upgraded Nomad. Hands down the Modkita wins with MRR, you just can’t beat the rpm and associated machine forces. Oh… forgot to record the log file but cut was up in the high 200 watts.
Mod - 0.8 cubes @ 30krpm, top speed due to vibration with unbalanced tool. Will try a Datron 4-1 today and hoping for 1.2 cubes.
1.5kw 24krpm - 0.65 @ 24krpm max. Both axial and radial docs were adjusted and maxed out
Also out of left field. What would you guys think about adding a small flywheel? Something to just smooth everything out and damped things out a bit. Maybe a viscous dampener…
Ran max in duty cycle mode, max load ipm, lets not get into docs please. Gotta look over the log more but its impressive. With this power the Nomad is rigidity limited and it should rip on a well setup Shapeoko.
@LiamN its shown to be plenty powerful already, the next step is making it smooth. A little weight wouldn’t hurt, it already spins up ridiculously fast.
Honestly was debating on trying to see if one of the smaller turbo manufacturers might take on the challenge to dynamically balance the shaft/nut assembly.
On my unit without a fan, you’d have to press off the lower bearing, press on a fly wheel and then replace the bearing. I’m guessing it wouldn’t be too hard if you had access to a lathe.
This is probably the area where the inefficient squirrel cage VFD controlled motors have the advantage as they inherently adjust motor torque current with their mechanical slip angle.
BLDC motors generally have less mass on their stators. They just have permanent magnets and not stator coils. This makes them more efficient but it also means less mass spinning so a small flywheel might not hurt. Definitely get it balanced though. Tuning the PID controller though should lessen the impact of the this.
A two flute endmill at the same DOC would halve the cutting force per flute. Increasing the endmill diameter would proportionately decrease force for the same MRR. Here’s a 3/8" 2 flute endmill that could do both.
Since that series of endmills apparently want at least a 0.00059" maximum chip thickness and a 0.113 WOC, the DOC was increased to 0.287" to provide about 4 lbf at the recommended 33418 RPM, as shown below.
The Datron endmill is only rated for 34,000 RPM, but the Kennametal is rated for 50,000 RPM. That would give you a MMR of 2 cubic inches per minute without increasing forces (if you could run it that fast and had sufficient power/cooling.)
Cuts the impact forces in half and doubles their rate, right? Using more of the helix (DOC) seems like it should help smooth things out too (like helical/spiral planer and jointer cutter heads.)
That Datron 8mm was the only high balance flat endmill I had in the arsenal, and with its wiper, produces the best finish at the highest MRR out of all my endmills. One day I’ll pick up a few kennametal though, even if that max chip thickness is weird.
I’ll test out multiflutes when I get back in town. It seems the Nomad should be able to push even a triple at decent chip thickness for dry cutting (very different than flood or mist coolant).
Makes sense now you mention it, high helix cutters which always keep part of a face cutting, multi flute cutters etc. It’s an argument for depth over width of cut too. I guess a fly cutter is the high vibration counter example.
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