PLA wood filament: a special treatment?
PLA wood has a beautiful natural texture that I wanted to try. But when I used it in my second print, it clogged the nozzle (solved). I know this filament is composed of 70 % PLA and 30 % recycled pine wood fibers.
- Are there special indications for this kind of filament?
- Should I modify the temperature, or other settings?
PLA and wood fibres = wood filament
Most wood filamet consists of about 60-70 % PLA and 40-30 % wood fibres. This basically implies that PLA temperatures should be used. It can be printed with standard 0.4 mm nozzles, but it is adviced to be printed with a larger diameter nozzle. A larger nozzle will less likely to cause nozzles to clog (more area for the fibres to pass through).
Basic printing advice
Start experimenting with relatively large layer heights (0.25-0.3 mm layer heights). Printing speeds should be held high to ensure relative short residence times in the hot end (in the range 50-80 mm/s). Short residence times prevent degradation by heat resulting in clogging. It is best for wood fibres filled filaments to not have the filament to stagnate (e.g. pausing). A higher retraction speed and distance might be needed because the filament usually is a little more runny compared to plain PLA.
After printing, you should retract the filament from the hotend so that during next printing jobs heat up cycle, the filament doesn't degrade and clogs the nozzle. Alter the end script G-code and also use priming scripts at the start and/or do not forget to use a large skirt of multiple lines or a considerable length. As always, you shouldn't leave the printer unattended, regularly check the printer and shut down the printer when there is something wrong, e.g. not extruding. Also note that wood filled filament is reported to be abrasive to brass nozzles, a (hardened) steel nozzle or a Ruby nozzle should mitigate wear problems.
These settings have proven to work, but are not a guarantee, these settings should provide a reference to start experimenting on your own printer:
- Temperature: 190-205 °C
- Layerheight: 0.25 mm
- Speed: 50 mm/s
- Minimal layertime: 8 s
- Bowden type extruder
- Retraction speed: 40 mm/s
- Retraction distance: 5.5 mm
- Direct extruder
- Retraction speed: 25 mm/s
- Retraction distance: 1.3 mm
I would add that deliberate changes of hotend temperature during a print can cause varied darkening of the extruded material (carbonization), and if done well looks almost like grain lines in real wood.