Removing Carbonized Buildup From an Ultimaker's Nozzle

Like any piece of equipment, FDM 3D printers require regular maintenance and cleaning. After six months of service, LimbForge's printers in Port-au-Prince, Haiti needed some TLC. In addition to oiling rods and greasing leadscrews, we have added this nozzle cleaning procedure to our protocol as it is extremely effective at removing any materials stuck inside the nozzle and is pronouncedly more effective than the traditional "atomic purge" because it agitates and abrades the adhered material in the nozzle before attempting to pull it out with a section of solidified filament.

For this procedure, you will need:

• A power drill
• 20-25cm (8-10in) of filament
• A pair of pliers

Power on your Ultimaker, set the printhead temperature to something above the melting point of the filament. Remove the filament guide tube and then removed the filament from the print head.

Take a 20-25cm long piece of filament from a spool and carefully straighten it. Then insert one end into a power drill and set the speed to "high".

Heat the nozzle up to print temperature or a little higher. Carefully insert the filament chucked in the power drill into the nozzle and push down until you can see filament exiting the nozzle. Pull the trigger and push down firmly, careful not to apply too apply enough downward force to bend any of the linear rods. Guide the filament with your other hand to keep it from buckling. After 10 seconds or so, stop, un-chuck the filament, and turn off the printhead heater.

Wait for the nozzle to cool to between 60 and 100C (depending on what material you are using). We found that 80C was effective for 3DUniverse brown PLA. Once the printhead arrives at the target temperature, use a set of pliers to firmly jerk the filament out of the nozzle. If there is carbonized material built up on the interior of the nozzle, it will come out stuck to the filament.

Repeat this process, clipping the end off of the cleaning filament each time, until the filament comes out clean. Ideally, you should be able to see down the bore of the nozzle and see light through the tip.

Using clear filament may be helpful for identifying build up and using a filament loaded with carbon fiber or some other particulate material may help with abrading the buildup off of the interior of the nozzle.