Seriously, watch the video, although I added structure to stop it from wobbling, for in moments like that the top of the gantry was going 5 times a second a few millimeters out of the printing pats, it still rocks but only for a scarce half a millimeter at the top.
The inertial mass of the printing head is neglectful?
Don´t think so.
now imagine a head with direct drive that has 2 nozzles, that goes 800 grams weight on this structure, it makes me wonder...
And I am working on to make a printer that wights a ton, with a head of 10 double nozzles direct drive.... that makes it some 10Kg that pounds left and right, back and forth up to 10 times a second... need some strong structure to take that, and strong steppers, and strong belt... or I go direct to linear servo stepper actuators from CNC industry.