I have sometimes problems that the Woodfill from Colorfabb gets stuck in the nozzle at an Ultimaker 2. Today I was away for ten minutes and only some kind of oil was drupping out of the nozzle. See images attached.
Everything ended up fine after several times of cleaning with the atomic method but what can I do to prevent the nozzle to get blocked?
What Temps, speeds, layer height etc are you running? do you have extruder/spooler upgrades? how many hours on PTFE insulator? is it only woodfill you have a problem with?
You can also add a custom gcode at the end of printing, this could include a retraction of a.e. 30mm. So you get at least most of the WoodFill out of the hot nozzle. Also a larger nozzle diameter might help, as the fibers can cause extra resistance in the bowden-system, when they barely fit through a tiny nozzle. Cheers, Marius Breuer
We had exactly the same problem on our Ultimaker 2 and Woodfill. Ended up buying a new nozzle because our prints kept getting ugly/bad results with other materials after the woodfill.
Most important: Turn off retractions. Keep it flowing. Retractions lets in air and the water in the filamenet vents away. Woodfill 125-135% material flow. It is right what the others say, bigger nozzle helps and also looks beautiful, but is not strictly necessary.
First layer 220C to make it stick, then lower to 210-215.
An Olsson Block with exchangable nozzle helps.
Make sure you print quite fast. at least 50-60mm/s at 0.2mm layer (100-120mm/s @ 0.1mm layer). If you go below that volume (4-5mm3/s) you are likely to have progressive clogging.
Make sure the minimum layer time will not interfere with this speed.
Thanks for the advice! It is now already printing well for 4 hours. So probably the advice of Xeno, cleaning the nozzle now and then, is worth a try! And I will play a bit with the retraction length!
for your interest: 210C, 110%, 60m/s, retraction normal.
We had the same issues with woodfill and clogging, and despite all changing the temprature, printing speed, insulator and more, we couldn’t get reliable results with woodfill on print jobs longer than 1 hour.
In the end we switched to an olsson block, with 0.8 brass nozzles, and so far it has worked like a charm. It takes some trial an error to get the settings right for printing with woodfill in a 0.8 nozzle, but we got much better results.