The old saying, “garbage in, garbage out” may need to be re-evaluated. Students at Victoria University of Wellington are developing a machine that recycles old milk jugs, extruding an HDPE plastic filament that can then be fed into a MakerBot for 3D printing.
The process involves grinding the plastic into small pieces, then pressing these through a heater and extruder plate to produce a continuous bead of the proper diameter for the MakerBot. Nichrome wire — the stuff of hair dryers and toasters — forms the heating element, and this must be regulated within a specific temperature range for different plastics. The initial grinder design is hand-cranked, but they are working toward a fully automated system. It appears that the machine could also recycle old MakerBot output, provided the grinder has sufficient torque.