Originally Posted by
NervesofSteel
I am considering building a CNC router. I am in the wrap-my-head-around-it stage. Ideally it would work for wood and light metals.
Has anyone seen the use of a flywheel added to a router/spindle to improve the cutting? I think there would be little impact on energy use. It's possible that some favorable damping could be obtained through flywheel construction, I haven't really thought about that. Are such flywheels built into any routers now, that you know of?
The idea is the added inertia would even-out the load experienced by the motor. Obviously the motor rotor has rotational inertia: the question here is could such an added flywheel allow for a given motor to improve it's cut. My assumption is that the flywheel does not need to be very large or heavy, though I haven't made any attempt at evaluating that.
This is somewhat related to the flywheel action of a large-diameter bit, but in that case the cutters' relative distance from center mean that the router bit body alone can't comprise sufficient rotational inertia. This explains their sometimes-difficult behavior.
The major con is the added inertia with speed changes. If that's not a big problem, a smaller motor might be coaxed to cut like a bigger one.
It could counteract vibration more directly, reducing damping capacity expectations on the rest of the gantry, etc.
While fine-tuning might be necessary (size & weight), there might be wide tolerances for acceptable performance.
The ideal place to mount it might be the other end of a double-shaft motor. A safety shroud could be a good idea in some cases. In that location it won't interfere with normal machine operation.
I started off posting this in a wood router forum, but it occurs to me the idea would apply as readily to metal machining, so I begin to wonder if machinists had thoughts or experiences with it.
If anyone experiments with this, I'd love to hear about it! Eventually, I probably will, but it will be months or years based on my current project list...
Thanks!
Keith