The New Hotness

Although the 3D printed tires for our Terracycle chain idlers fit nicely, adjacent TPU threads didn’t bond well:

Based on some earlier items, I’d been printing TPU at 220 °C, but 230 °C fuses the threads together:

The filament turned out to be 1.79 mm diameter, rather than the nominal 1.75 mm, and a few iterations showed a 0.95 Extrusion Multiplier worked much better.

Those were printed at 30 mm/s with 0.25 mm layer height.

I now have a good stock of spare tires, each slightly different than all the others:

The first two slightly delaminated printed tires will remain in service until they show signs of falling apart, because I’d rather ride the bike than fiddle with it.