by orcinus » Mon Aug 27, 2012 1:13 pm
Sorry, don't have any numbers here, i'm away from home.
I print at fairly low speeds (up to 60 mm/s), but have done stress tests up to speeds high enough that they're not attainable with the Hadron footprint and default accelerarion in Marlin. Anyway, it's not the speed that causes loosening and stress, it's the jerk.
I did a few stress tests with high-frequency prints (patches of very small range, repetitive, fast movements) and saw no loosening.
Frankly, i don't see a way things could loosen in the first place. The friction of wheels over makerslide is orders of magnitude lower than friction of the bolts, nuts or even the eccentric spacers against the plate or bearing.
Regarding "knowing what people are doing", i've recently come to realise that people in the 3d printing (and reprap in particular) communities often do blunders that you'd never expect them to do, considering the prints they output or experience and effort they've invested in 3d printing. For example, i've read a post from someone the other day outlining how their Nth 3D printer developed a "sudden" fault and outlining at length how strange it is that lateral forces made their off-center mounted screw terminal on a build platform develop a solder fault after a few 100 hours of printing. Musing how they should probably devise a strain relief next time... SERIOUSLY?! Yathink? After xx printers and xxxx hours of printing, that only occurred to you just now?!