To avoid risk of clogging the nozzle, AON3D recommends using different heater block assemblies to print materials whose material swap temperature ranges do not match. E.g., If you would like to print ABS (temperature range 210-280C), then switch to PEEK (360-440C), it is best to use different heater block assemblies. To print ABS (210-280C) and switch to PC (250-330C), the same heater block assembly could be used, but only if great caution is taken to flush all the ABS material before printing with PC. To print ABS (210-280C) and switch to ASA (230-280C), the same heater block assembly can safely be used. Please contact firstname.lastname@example.org if you would like to purchase additional heater block assemblies.
If you are not familiar with the process to load filament into the machine and extruder, please read through the guide to loading filament before attempting this procedure.
When you switch filaments without changing the heater block assembly, there will still be a small amount of the old material left in the melt zone of the hot end. This material must be cleaned out before printing. For filament swaps where the old and new materials have similar extrusion temperatures, the old material is cleaned out of the heater block and nozzle by purging with the new material.
To switch between materials with very different extrusion temperatures, it is necessary to use one or two materials to step up or down to bridge the temperature difference. The graph below shows the temperature ranges in which it is safe to purge each of our materials. Before switching materials, check that the temperature range of the new material overlaps the old material.
To clean out old filament, first heat the hot end to extrusion temperature for the filament you will be removing.
Open the extruder by pressing the two tabs at the top together.
Gently pull the old filament out through the extruder.
Turn off the heater for the nozzle you are using to give you more time to load the new filament.
Cut off the melted tip of the filament before removing the spool from the printer and loading the new filament.
Load the new filament into the extruder and down to the hot end.
If you are moving to a higher temperature material, raise the extrusion temperature to the minimum extrusion temperature for the new material. If you are moving to a lower temperature material, do not change the extrusion temperature setting, unless it is outside of material swap temperature range for the new material.
Do not raise the temperature above the maximum temperature for either filament! Do not leave the hot end at extrusion temperature for long periods of time (>5min). This can cause the filament to break down or burn and may clog the nozzle.
Gently push the filament in until you see material start to come out of the nozzle.
Close the extruder by pressing only the long tab on the top to release.
On the touchscreen or browser interface, navigate to the Control tab.
Select an extrusion distance of 100mm and a speed of 3mm/m.
Tap extrude once to push 100mm of filament through the system. Unless switching between materials which are visually similar, you should be able to see the filament change colour and appearance as the old material is flushed out.
Tap extrude again to fully flush the system.
Purging with 200mm of filament should be more than sufficient to clean all the old material from the heater block and nozzle, however some materials may require more purging. CF filaments and other filled filaments will require additional purging distance to fully clear the nozzle of the all filament and particles. Try an extra 100mm.