Why is the 3d printer nozzle clogged?
Clean clogged nozzle. The nozzle is clogged for a variety of reasons. Sometimes it is very difficult to trace the real cause. We must radically distinguish ourselves in two categories. The first one is those who are beginning and the other is of those who already have a decent experience. Let’s say that the blockages of the little experts are easily recoverable because are only errors or behaviors to vary. While blockages that occur to experts, or at any rate to those with some experience in the field may depend on external factors or failures.
When we are in the presence of a blockage we also find ourselves in the case of “extruder clicking”. So in the case of loss of the engine steps of the extruder, that not being able to push the filament beyond the block in the nozzle, makes the sprocket back with the classic noise: “tick-tick”. There are also other possibilities of extruder clicking, I invite you to read them here: Extruder clicking – What to do when the extruder motor clicks and fails to push the filament.
Among the most frequent causes that can happen to who begins the path in the 3D printing. We can cite:
- A wrong temperature setting. An extrusion too “cold” does not allow the total dissolution of the material and therefore a difficulty to extrude it.
- Printing bed leveling problem, with the nozzle too close to the plate we have no extrusion and this is read as a clogging.
In rarer cases if it occurs even if you have provided yourself to mount the hot-end block. If you do not push the PTFE tube in bar (equivalent to pushing it inside very strong) can form a room that houses loose material, but at the first retraction, this material solidifies and will no longer be possible to go forward or backward.
- Even poorly preserved filament, which has taken moisture can cause clogging. In this case, simply remove the moisture from the filament with a dryer or trivially with the oven at home. See the guide: [Guide] How to easilly recover wet filament.
Nozzle clogging: for the more experienced
Eliminating the simplest cases, brought more by lack of experience or by real mistakes we move to more borderline cases. These cases are more rare but not for this reason not resolvable.
If in some cases in the list everything is resolved with some mechanical adjustment or software in these cases you must always proceed to cleaning. Here are the other cases:
The filament is “grained” by the toothed wheel of the extruder. The filament powders remain on the filament and once arrived at the height of the nozzle solidify, clogging the exit.
- The ambient dust. Exactly as described in the previous point a dirty filament can drag it up to the nozzl. And forms a cap kneading with the molten material clogging the nozzle.
- Even the not purging and not cleaning the nozzle after changing various types of materials can lead to clogging.
Another cause could be that the filament too soft (such as TPE/TPU) are not easily dragged inside the hot-end thus forming lumps of material. These clog the passage through the nozzle.
How to check if the nozzle is clogged
The first clear warning signal is auditory. So when we start to hear a ticking sound coming from the extruder, we can already imagine something happened. Then simply disconnect the pressure from the pusher and push the filament manually.
If it doesn’t move and we don’t see anything coming out of the nozzle then we’re in the case of clogging. Be careful not to push excessively, I did and happened to damage the ring that holds the PTFE tube in place. Not much damage, but still damage.
Clean clogged nozzle: Different cleaning methods
Clean clogged nozzle. Depending on the old age of the clogged nozzle and the cause of the clogging we have 3 different cleaning methods. Here I list them from the softest to the most invasive, to use of course in order. Each of us will be able to decide for ourselves when to apply one rather than the other.
Method 1 (soft)
Problem: the nozzle starts to give some problems, extrusion is not always constant. The clogging can occur when printing has started and we can have a transition part where the printing seems inconsistent.
Evaluation: We are probably in the presence of a nozzle partially blocked by debris, dust and parts of other filaments.
Material needed: The only thing we will need is a stretch of filament for cleaning nozzle.
Procedure: Simply insert the cleaning filament and complete a small print, such as the calibration cube. When for a few minutes you will not see any more residue from the nozzle you can also stop the procedure.
Method 2 (medium)
Problem: The nozzle is completely clogged, even if you try to defuse and push manually you don’t see material coming out.
Evaluation: we are in the presence of a real clogging.
Material needed: We will need a set of nozzle cleaning needles and a stretch of filament for nozzle cleaning.
Procedure: Lift the nozzle a little, about 10 cm, and heat the hotend at maximum temperature. Insert the cleaning needle into the hole from which the filament comes out and move back and forth until you see the filament come out. Now thread the nozzle cleaning filament and push manually until it gushes from the nozzle. Now print a small figure to be sure to remove all the obstructive elements.
Note: If you happen not to see the filament gushing or otherwise to keep the block even after inserting the needle you may have an excess retraction block. There are many cases that can lead to this type of extrusion block.
- Exactly a too high value of retraction distance.
- An inaccurate assembly of the hotend block.
- A weakening of the ventilation of the hotend.
- The excessive wear of the PTFE tube.
- A lot of other…
In all these cases the clog (obstruction) is not at the level of the nozzle but in the tube or throat. To solve it will be necessary to completely disassemble the hot end and we will find some returned material dissolved and re-slidified to greater diameter. For the solution we can cut away a piece of PTFE (if long enough) to try to remove the material or replace it directly. With a hotmetal throat we can also help with a drill and a 1.5 mm tip to remove the block!
Method 3 (hard)
Personal protective equipment (since we will deal with dangerous objects) that you will need:
- Protective glasses.
- Protective mask.
- Working gloves, better if very thick to resist any contact with the soda and high temperatures.
Procedure: Turn on the printer and set the highest possible temperature. Keep the heating tank still and unscrew very quickly (it’s hot!) the nozzle. Expose the nozzle to the 400+ nozzle of the paint stripper by passing the needle from time to time for cleaning. Try to clean it even from internal and external residues with simple towel. Once finished, put a few flakes of caustic soda in a glass or any other glass container and insert the nozzle ( or better the nozzle) and pour a little water. Stir carefully until completely dissolved and let rest for 8 hours.
When you return, the nozzles will be new again.
Alternatively, you could buy a dozen replacement nozzles and simply change the nozzles, to preserve the closed ones and perform the procedure only when you have accumulated a dozen. Given the minimum cost of the nozzle I recommend it!
How to figure out if the cleaning was thorough enough? Simply will just look through the nozzle towards a light source. If we see a nice round ball of light we will have done a good job, otherwise we have to repeat the procedure.
In case you have of any doubt about the methods or some passage write it in the comments, we will be happy to help you!