Quotelkclohhh..... riiight, okaaay, so the belt's speed only comes into play if the BELT's mass is significant. THAT would be where the pulley system would have a quadruple effect, but we already concluded that the belt's mass is negligeable, so it's okay. does that sound about right? Pretty much -- I still think it's double, not quadruple (See post I wrote at the same time as yours...), but eiby benson - Extruded Aluminum Frames
Aha, I finally figured out where you're getting the 4x acceleration. You're using the formula v^2 = u^2 + 2*a*s, but that's not a particularly helpful equation for understanding this; it's for considering an acceleration (a) applied over a certain distance (s). You can use it here, sure, but it's really the long way around. First you have to figure the distance over which the acceleration occursby benson - Extruded Aluminum Frames
Quotelkcl scenario 1: 1 belt, travel speed 100mm/sec, head acceleration target 3000 mm /sec. belt acceleration is directly proportional, belt undergoes acceleration of 3000 mm / sec. Sure. But I'm not sure why we're calculating belt acceleration. As long as the belt's mass is small compared to the mechanical parts, it doesn't matter much. Tension due to print-head and gantries: Let's assign anby benson - Extruded Aluminum Frames
Quoteprot0typ1calFail to see how this twist occurs, as there isn't any force acting on the carriage, other than linear loads from the crossing rods. Inertia. Consider when the extruder is at, say, X+ limit of travel, and you're accelerating in the Y+ direction. The whole mess wants to rotate clockwise. How much a problem this is depends on how crazy you get with accelerations. lkcl is trying toby benson - Extruded Aluminum Frames
Yeah, where have I seen that mechanism before... https://commons.wikimedia.org/wiki/File:Etchasketch.jpg Note that if you actually wrap the outer belt around the inner belt on the pulleys, there's gonna be some slip as they go around the corner -- may or may not be a problem. You can of course avoid this by using two pulleys, one above the other, but that's got obvious downsides. Better, you canby benson - Extruded Aluminum Frames
Quotelkclinterestingly, prot0typ1cal, the same type of "shear" is simply not possible in the EdgeXY concept, in neither X nor Y (green or yellow blocks). let's go over it: * push left yellow block "up", push right yellow block "down". this results in blue belt on left yellow idler trying to become LONGER (tension)... but *at the same time* because blue belt on right yellow idler is on the OPPby benson - Extruded Aluminum Frames