Clogged nozzle is very common. By its very nature, the 3D printer is a work machine, and apart from the inevitable affection that at some point you feel for everything that gives us satisfaction, it has to work. This means that it must constantly moving and melt kilometers of filament. And then, this melted filament must pass through a hole of 400 microns! (0.4 mm).
Before or after the time comes for all printers when this hole, for various reasons, stops and we must, despite our efforts, find the solution.
These clogs are mainly due from:
- dirty filament that drags inside grains of dust, which kneading with the plastic forms lumps larger than the exit hole.
- Incorrect temperatures can cause the wire to harden abnormally, which will have more difficulty being extruded.
- The filament, if left in the extruder from one print to another can give itself problems of filling. When we have this problem with a specific filament, once the printing is complete, you should retract the filament of 2 cm by repetier. Remember to enter 2 cm at the next print. The filling problems will disappear and we will have perfect prints from the beginning.
When we are in the presence of a filling we can switch to remedies basically in 2 ways, the fast way and the thorough way.
Clogged nozzle: FAST METHOD
- The fast way involves heating the extruder to a temperature at least ten degrees higher than that used for printing the material that caused the blockage.
Then through the use of a nozzle cleaner, which in essence is a needle of the precise measurement of the diameter of our extruder. It will be inserted and the material that comes out will be cleaned. When it seems unblocked we will have to push the thread manually and see that it flows and comes out with a normal diameter and flow. If this is not the case, you will have to continue with the cleaning.
We use this method when the extruder is new and can’t be finished inside it. Otherwise we will have to proceed with the thorough cleaning.
Clogged nozzle: THOROUGH CLEANING
- The thorough cleaning involves disassembly of the nozzle, always remember to dismantle / reassemble the nozzle to the maximum temperature that our extruder can reach.
At this point we can proceed to the heating of the nozzle by means of a blowtorch, paint stripper gun. If we are in a house without professional tools, through the fire emitted by the stove of the house. I recommend the fire of the stoves as it is very caloric (if blue).The temperature we need to properly remove the plastic. We do not try to do this job with a simple lighter because it is not caloric enough and will burn our plastic. The lighter will leave a lot of residue and turning the nozzle into a piece of charcoal. At this point, through the nozzle cleaner we talked about before, we will proceed to get rid of all the plastic present (alternatively to the nozzle cleaner we can use a guitar string to throw away, we will have to choose the A of the electric guitar or the King of the acoustic/classical).
To judge our cleaning work we can place the nozzle towards a light source and try to look inside. If you see a nice circle of light you will have freed your nozzle well.
Clogged nozzle: Finishing
Once this operation is finished, depending on whether you are using ABS rather than PLA, you can immerse your nozzle in pure acetone (MethylEtilChetone for ABS) or caustic soda (PLA) and leave it to rest overnight. Personally, after having rinsed and dried the piece well, I put a drop of lubricating grease inside it (the grease resists high temperatures). The only precaution at this point is that after mounting it pushes out more filament than usual, until it eliminates all residues of grease. (I found that this method prevents re-entry for a long time).
A very easy test to verify that you have properly released the nozzle is to point it at a light source. Now check that the light passes through. To judge the successful cleaning work we have to see inside a nice precise circle, exactly as in the picture above. If on the contrary we see a crescent or other geometric figures it means that our nozzle will need another pass and we will have to start the cleaning process again from the beginning.
Clogged nozzle: LAST OPERATIONS
If we had an extruder blockage and did not notice it immediately, maybe, due to the lack of flow, the part of the filament in contact with the wire pusher wheel is completely grated. Our extruder will be full of pulverized filament residues.
In this case it is advisable to clean the whole apparatus very well and eventually dismantle it completely to provide for a more accurate cleaning (if we dismantle for maintenance the entire extruder remember to check the state of the PTFE tube (new capricorn tube is linked) inside the screw inserted in the radiator and replace it if it is not perfect). Once everything is ok, cut off the part of the defective filament and we can get back on track.