Anti-ondulation XYZ du coupleur souple 5x8

thingiverse

<b>Edit 2018-12-06</b> : An improved version is now available in remixes or directly here: https://www.thingiverse.com/thing:2748114 This piece, inspired by Lulzbot printer mechanics, is dedicated to Dagoma DiscoVery and DiscoEasy users who employ this head: https://www.thingiverse.com/thing:2478810; it allows for Z-axis clearance to implement these parts. A flexible coupling is not a shaft centerer: the goal here is to center the lower ends of Z axes and eliminate 5x8 flexible coupling wobble. A flexible coupling absorbs imperfections in alignment between two rotating axes it connects. Depending on the inertial center of what it drives, it deforms not only angularly but also and more subtly in XY and Z (on the order of +/- 50 to 100 um) and generates wobble. I recommend implementing these parts with high shaft centerers like those: https://www.thingiverse.com/thing:2538950 and blocking high bearings with screws on each face (this requires longer threaded rods by several centimeters). Some comments will say, "Just get rid of these flexible couplings and replace them with rigid ones"... that's indeed another option (and you'll find several people who have already shared this type of solution on Thingiverse), but the problem with this approach is that deformation inertia is then transmitted directly to the motor axis. You can see in the last image, the gain obtained before and after implementing this piece above each coupling. (BOM) - 4 M3x12 screws - 4 M3 screws - 4 M8 screws - The bearings used are 619-8-ZZ-INOX (int. diam. 8mm, ext. diam. 19 mm, ep 6mm) like these: https://www.123roulement.com/roulement-619-8-ZZ-INOX.php or by searching with the term "Bearing 8x19x6" on AliExpress, Banggood, Amazon, etc...