Flexible shaft extruder for ultimaker original

youmagine

I was running into problems with the Bowden setup and wanted to avoid putting the motor on the extruder (seemed too heavy). A flexible shaft seemed like a good solution. As usual, my brilliant ideas often get beaten by others, but I shamelessly stole the aspects I liked from this existing design and incorporated them in my setup. Unfortunately, the "fix" was for the Ultimaker 2 and required buying worm gears (similar to https://www.youmagine.com/designs/modular-printhead-ultimaker-flex3drive-merlin). Here is a version that fits on an Ultimaker Original and Ultimaker Hot-End. Print out all the parts, file down the teeth on the gears so they fit, and use a lubricant for final assembly of the worm gears (vaseline mixed with graphite seems to work well with PLA). The flexible shaft needs to be taken apart, resulting in one flexible metal shaft (about 3-4 mm diameter, with a square end -> that goes in the worm gear; cut it to size and attach the other end to the motor coupling). Thread the flexible shaft through the Bowden tube (which you no longer need for filament) to add stiffness and avoid supercoiling. The two scavenged bearings go on the top and bottom of the worm gear. To get the whole thing to work, change the stepper setting in hardware from whatever the default jumper setting is to a ~4x increase; after that generate a new firmware for the Ultimaker with the corresponding feeder settings and you are good to go. I'm sorry I forgot what my precise settings are, otherwise I would have stated them here. The closeup of the worm gear shows the quality of the prints I can get with the current design; it's not really an improvement over the stock head+feeder, but now I have no more troubles with filament grinding or warping within the Bowden tube with flexible filaments.