bondtech bmg extruder carriage robo R1+

thingiverse

2/7/18 UPDATE, I have made changes to improve the vertical rigidness that was causing issues during the 9 point level and throwing off the Z offset in an unpredictable manner. The unit now has a removable plate to make it easier to remove the hotend and extruder assembly, a beefier cable harness that won't crack as easily, and easier access to the bottom right mounting screw through an opening in the belt tensioning platform. Any feedback is appreciated to help make more improvements. 9/30/17 UPDATE. I have found that PLA works best so far, both PETG and ABS flexed too much when it was doing the auto-level routine, even with mesh leveling. The PLA frame had a bit more rigidity which is important. 6/22/17 UPDATE: I am working on a new version to allow the standard-sized stepper motor; the pancake stepper has problems overheating. I have been looking at Bondtech extruders for a while and finally decided to go for it and get the Bondtech BMG extruder. I didn't want to do a Bowden setup, so I decided to remix Mike Kelly's replacement X carriage. The X carriage assembly with dual fans and hotend is 300g lighter than the stock Robo setup with E3Dv6 and dual part fans. I also had to remix the fan shrouds so that the hot end would clear the bottom of them. If someone knows who the original designer of the fan shroud is, please let me know so I can link to them. All the clearances are tight in order to have it all work together, so patience and very tight tolerance control is needed. Here's a link to the linear bearings I used: OTRMAX 4-Piece 8mm Longer Linear Motion Ball Bearing Double-Side Rubber Seal Linear Bushing CNC Part LM8LUU. https://www.amazon.com/dp/B01MXTYSVL/ref=cm_sw_r_cp_tai_ztHozb08ACK56