Cube3 Back-2-Basics Bowden Tube (B2B Project)

thingiverse

This is the final component of the Back-2-Basics Universal Cartridge Upgrade for the 3D Systems Cube 3rd Generation 3D Printers. This part represents a bowden solution between the modified cartridge bulkhead and the Cube3 B2B extruder housing. To make this part, we recommend using PLA on the Cube3 left side extruder. Rotate the parts 180 degrees if you are using the right extruder. The unique implementation of the bowden tube for the Cube3 printers eliminates the need for push-fittings. Push-fittings often fail for Cube3 users because keeping the tube from rotating is a problem when handling Cube3 hubs and extruders. This solution solves the rasping of the grippers on the tubing, which forces tube shortening and breaking fittings. With this implementation, you can achieve full B2B adaptation with just one 1/2-meter length of 4mm tubing. To implement this solution, you need to 'machining' a groove in the bowden tube. This involves adding a 2mm wide, 1/2mm deep groove 5mm from the end of the tube. The groove will hold a 'circlip' to maintain the dedicated tube-nuts. A printable device to achieve this groove has been developed and will be posted later. Currently, we are using a 1.8mm wide section of the thick tube buried in the stock cartridge case and slitting it. This is 'the keeper' of the tube. You may need to clean up the seam-pip where the circlip resides on the hotend tube-nut. The case bulkhead side also needs to seat fully. We are working on a cube3-specific print to make the circlip. This will be added when completed. Any tough ring the size of the mating bulkhead and extruder housing tube-nut counterbore would work if you don't have spare 'stiffening tubes' from salvaged cartridges. Edit: We've added a printed version of the Circlip. It is a 70 micron print of the included STL file. When setting up your own print, make sure the seam is in the middle of the clip as this is one of three 'strong points'. Do be sure to adjust out any "elephant foot". Use a very generous gap to make these. Blue tape is a good way to ensure good adhesion. As much as the Capricorn tubing is cool and all, we prefer to see our filament being fed into the bowden tube. We recommend testing your bowden tube ID. Many 4mm PTFE tubes have an ID of much less than 2mm. To qualify tubing, push a 2mm bicycle spoke through the tube. There should be minimal restriction along the 18" length. We highly recommend qualifying your tubing using this benchmark. Flattened filament going through the driver mechanism can easily reach a width that a tube too small will trap the filament causing the print to fail. This is essentially the issue with half of the stock Cube3 cartridges. Stay tuned for further postings of the B2B Cube3 cartridge upgrade.