Filament Nudger for 3Doodler

Summary

The Nudger makes it possible to use the same filament that is used in a regular FDM printer and therefore you can repair failed prints using the same filament.  The patch can be smoothed out with a heat-controlled soldering iron such as the Weller 51.  

For various reasons, the 3Doodler sometimes stops extruding. This can happen with any 3D Printer. However, the 3Doodler is exceptionally easy to get going again by giving the filament a gentle nudge. The Filament Nudger is a hack to reduce the number of times the 3Doodler stalls or jams by providing a continuously nudging force on the filament.

The automatic Filament Nudger was designed to be powered by a pair of rubber bands, and it is cocked by pulling back on the Filament Grabber mechanism. The Nudger works with or without the Phaser Handle described in a previous blog [How to 3D-print a Handle and Trigger for the 3Doodler (and to make it look like a Phaser)](http://www.interlockroc.org/20... ).

The Grabber works like a 1-way clutch, pulling the filament toward the 3Doodler but releasing the filament when pulled in the other direction or when the Grabber bumps the back of the 3Doodler. The force applied by the rubber bands is effective in keeping the extruder going, but is not strong enough to prevent the filament retraction which conveniently keeps the 3Doodler from oozing between extrusions like a glue gun does.

When used with the filament sticks provided by 3Doodler, the Filament Nudger has the benefits of (1) reducing extruder stalls and also (2) it lets you install a new stick any time after the trailing end of a stick disappears into the 3Doodler. 

Without the Nudger, a new stick may fall out when the 3Doodler is tipped upward before the new stick is engaged, and this can be annoying.

Instructions

• Create a hinge pin for the Grabber with small piece of filament, and put button heads on the pin with the 3Doodler.
• Attach the Frame to the 3Doodler with a zip-tie.
• Cut (2) 1/8 inch bamboo skewers to 7 inch lengths and insert them into the Frame (drilling out the holes if they are too tight, locking them in with small nails if they are too loose).
• Insert the Grabber onto the filament and skewers as shown.
• Insert Filament Guide over skewers and filament as shown (drilling out the holes if they are too tight, locking them in with small nails if they are too loose).
• Hook rubber bands over Grabber and attach them to Frame as shown.