Kossel linear bearing carriage for Trick Laser 3/8" barbells

prusaprinters

When I found out about Trick Laser's nifty ball-cup Kossel arms with plastic barbells to guarantee arm spacing and reduce joint lash (see http://www.tricklaser.com/), I was immediately intrigued, but I couldn't find any designs anywhere for a carriage design using the barbells on a linear bearing with belts (as my Anycubic Linear Kossel XL uses) -- so I made my own. It has a built-in belt tensioning mechanism to boot, although the structure required to support it adds some weight it could do without. At my printing settings the base comes to about 18g, which is a lot heavier than the original carriages it replaced. My original design just mounted the barbells "naked" on the top of the carriage, but I found that the barbells were soft enough to allow a lot of flex (and thus ringing) unless they were constrained right up to the balls (laff). With proper constraint, though, this is a very rigid mount. You'll need three each of the carriage, lock bar, and tension insert, plus: 3x M3x20 bolts for the tension inserts (you could get away with an 18 or 16, you just wouldn't have as much travel) 9x M3 nuts (3 for the tension inserts, 6 for the barbells) 6x 10mmx1mm washers for the barbells 6x M3x12 bolts for the barbells 3x M3x8 bolts for the endstops The carriages also need 4 M3x8 bolts apiece to attach to the linear bearings, but the original hardware will work fine. Note: This mounts the barbells pretty high, so you'll probably need to modify a few settings in your configuration; on my machine, the carriage offset went from 20.6 to 29.8. Your mileage may vary. If you don't have an effector to go with the barbells already, I designed a pretty rad (if a bit overspecialized) bowden-cooled one: https://www.thingiverse.com/thing:2884959 Print Settings Printer: Anycubic Linear Kossel XL Rafts: No Supports: No Resolution: .2 for the base and tension insert, .1 for the lock bar Infill: 40% for the base, 100% for the insert and lock bar. Notes: The carriage is NOT meant to be printed at high infills. I printed with 40% cubic infill and three walls (plus Cura's alternating extra wall) / six top/bottoms (1.2mm all round, that is) and have had no durability issues so far. The other parts should be printed in beast mode, especially the lock bars. I used Hatchbox black PLA and that seems to be fine. NOTE: the lock bar does need supports, but set the angle to about 85 degrees so your slicer only supports the inside and not the shallow outer angles, which shouldn't need supports at .1 layer height. How I Designed This Designed in SketchUp from scratch, using the original Anycubic carriages as reference for the self-locking mechanism. Category: 3D Printer Parts