https://www.youtube.com/watch?v=3IGQ_8K3tGI
this is a quick video of the horribly cheap and cheerful taobao $150 plus $40 shipping 3d printer making a HELL of a racket, successfully PRINTING at 200 mm / sec. acceleration settings have been turned up to... enormous: 4000 mm / sec^2 for X and Y, and 9000 mm / sec^2 for the extruder.
in previous tests i was running at 2000 mm / sec^2 and at 120 mm / sec print speeds there was clear signs of "bulging" along the 0.7mm wide screen bezel, where at the last moment the print head would slow down *but extrusion clearly didn't*, and instead of a nice line you get this "teardrop" effect. by putting the acceleration so insanely high that artifact *DISAPPEARS*.
now, due to the bone-rattling speed the frame is clearly vibrating around, which results in this "wave" pattern as the printhead goes through this massive 180 reversal, *but*, i am amazed to find that the "wave" pattern stabilises after around 4mm and is not hugely noticeable anyway.
it's basically outperforming the mendel90 for quality, yet still matching it for speed. i'm... absolutely astounded. still to consider is putting in some acrylic / MDF / hardboard surrounds that would stiffen up the frame.
l.
--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68