Easy Servo Drive?

[JAZZCNC]

You say it will 'fault' you mean it will just stop? I thought the whole point was it will get back to position and carry on.

Yes it will stop if it's outside of it's following error parameter. You are loosing steps for a reason not because steppers are inaccurate. That reason will still be there unless you change something like use larger motors or change the tuning setup. Closed loop system will correct for some error before it reaches the following error threshold but still error happend and if while in the cut material will be lost.!

In your case with only happening on occasional Rapid moves then Closed loop probably will correct the error rather than fault. But thats an awful expensive route when just buying correct size steppers/drives and/or tuning motors correctly will give you exactly same results.

[Tenson]

I think part of the matter is my gantry is super heavy. It's probably good for cutting metal but I mostly cut wood and want fast feeds. Actually fast feeds are not a problem, it's fast changes in direction that get it confused, like zig-zag ramping on a tiny detailed pocket.

I'd probably build a whole new machine to go along with the servo motors, it it will not be the only thing I do to try and improve matters.

[JAZZCNC]

I think part of the matter is my gantry is super heavy. It's probably good for cutting metal but I mostly cut wood and want fast feeds. Actually fast feeds are not a problem, it's fast changes in direction that get it confused, like zig-zag ramping on a tiny detailed pocket.

So the problem is the wrong size components not steppers are inaccurate. Wrong sized closed loop steppers will still do the same.!!
Thou It's more likely you have the accleration set to high. Or like often the case both velocity and Accel set too high.

How much does the gantry weigh.? Do you have any pics of the machine.
What drives and how much voltage are you running them with.?