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3D printer clogged nozzle
Everybody who owns a 3D printer has experienced a clogged nozzle at least once, or most probably it will happen sooner or later. A clogged nozzle is a common problem and afflicts printers worth 200$ as well as printers worth 2000$. Replacing the nozzle could be a solution, but let’s assume that we have a Genuine E3D Hardened Steel Nozzle and that we don’t want to throw away a 20 dollars nozzle. In this case, we just need to clean it, and there are several simple or drastic ways.
3D printer clogged nozzle symptoms
When we are in the presence of a blockage we are also in the case of “extruder clicking”. So in the case of losing steps of the extruder motor, the crown gear will push against the filament making the classic “tick-tick” noise. There are also other extruder clicking possibilities. When we try to push manually the filament and it makes lots of resistance, then we know surely we have a clogged nozzle.
How to tell if a 3D printer nozzle is clogged
3D printer nozzles get clogged for a disparate series of reasons, sometimes is fairly easy to understand why it happens, sometimes it is not. So, for this reason, I will be dividing the guide on basic troubleshoot and in-depth troubleshoot:
Clogged nozzle basic troubleshoot
We have to start with the basics, so we will exclude every little calibration defect to have a good starting point.
Among the most frequent causes of the filament not extruding are:
Incorrect temperature setting
An extrusion that is too “cold” does not allow the total melting of the material and therefore difficulty in extruding it. This kind of obstruction can vary. Most commonly when the printer manages to extrude in the first place after some layers it will clog and print again. In this circumstance, the temperature is in the borderline point where it flows easily or it clogs.
Print bed leveling problem
When the nozzle is too close to the plate we have too little space to allow extrusion and this is interpreted as a blockage. It is easy to distinguish, after 3 or 4 layers the clicking of the extruder motor will stop and the plastic will flow freely. Also, we will notice some over extrusion for the first layers. (If you want to learn more, check my article on first layer issues)
Extruder Assembly
Most of these blockage issues occur when the extruder was not properly assembled or when the PTFE tube isn’t flushed against the heater block. A small room can form which will house loose material, at the first retraction, this material solidifies and it will no longer be possible to push the filament.
Poorly preserved filaments
Spools that have taken on moisture can cause clogging. In this case, just remove the moisture from the filament with a dryer.
Nozzle clogging in-depth troubleshoot
By eliminating the simpler cases we move on to more borderline cases. These cases are rarer but they do happen, and most of the time they require cleaning the nozzle first and after that resolving the initial problem.
Dirty nozzle
After a long time using the same nozzle, carbonized pieces of plastic will accumulate on the tip making it clog more often. Also, working in a dirty environment with lots of dust will worsen this problem. It is essential that we work in a clean environment and that we clean often the extruder gear. Very frequently the extruder gear will create lots of filament particles.
Heat Creep
When we can’t provide enough cooling trough the heatsink the material will melt before hitting the nozzle causing clogging. This kind of obstruction usually manifests after quite some time into the print.
The easiest way to exclude this issue is by touching the heatsink after 30 minutes and feel if it’s hot or not. If it’s cold we are fine, if it’s hot then we surely have heat creep. This can be caused by old or dirty printing fans.
Another cause could be that the too soft filament (e.g. TPE / TPU) is not easily dragged inside the hot-end thus forming lumps of material. These clog the passage through the nozzle.
3D printer extruder motor clicking
The first clear alarm signal is auditory. So when we begin to hear a ticking sound coming from the extruder we can already imagine that something is happening. Release the pressure from the extruder and push the filament manually. If it doesn’t move and we don’t see anything coming out from the nozzle then we are almost sure the nozzle is clogged. Try removing the filament and trim it so it doesn’t have any lumps at the end and try again with a higher temperature. If nothing moves then we need to clean it.
How to clean a clogged 3D printer nozzle
Based on the gravity of the clogged nozzle and the cause of the clogging, we can have 3 different cleaning methods. Here I list them from the softest to the most invasive, to be used of course in order.
Each of us can independently decide when to apply one rather than the other.
Clean clogged nozzle: Method 1 (soft)
Problem: the nozzle starts to give some problems, the extrusion is not always constant. Clogging can occur after printing has started and we can have a transition part where printing seems inconsistent.
This happens when we change materials rather often, printing ABS, and then PLA will cause some headaches without proper cleaning of the nozzle.We are probably in the presence of a nozzle partially blocked by debris, dust, and parts of other filaments.In this case, it could be handy using some cleaning filament. This cleaning filament is designed to adhere to any stray plastic left in the nozzle and remove it, also It has a quite high printing temperature to ensure it removes every kind of plastic debris.
Procedure: Simply insert the filament for cleaning and complete a small print, such as the calibration cube. If you no longer see residues coming out of the nozzle for a few minutes you can stop it right away.
Clean clogged nozzle: Method 2 (medium)
The nozzle becomes completely clogged, if you try to unclog and push manually you don’t see material coming out even with the cleaning filaments.
Materials needed: We will need a set of needles for cleaning the nozzle and a section of filament for cleaning nozzles.
The easiest way of removing the blockage is by Lifting the nozzle a little, about 10 cm, and heat the hotend to the 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 extruding easily.At this point insert the nozzle cleaning filament and push manually until it flows from the nozzle. Print a small figure to remove all the obstructive elements.
Sometimes, with some extruders, incorrect retraction settings can cause clogging so be aware of the maximum retraction distance. Try eliminating retraction and check if the problem still occurs.
Check also for excessive wear of the PTFE tube as it may lose grip and move from retraction.
In all these cases the clog (obstruction) is not at the level of the nozzle but in the tube or throat. To solve it, it will be necessary to completely disassemble the hot end and remove the clogging from the tube.
Clogged nozzle: Method 3 (hard)
Problem: Nozzle completely clogged.
Personal protective equipment (since we will have to deal with dangerous objects are necessary):
- 1.Safety goggles
- 2.Mask
- 3.Work gloves, preferably very thick to resist any contact with soda and high temperatures.
Materials needed:
- 6 or 7 wrenches
- Pliers
- Paint stripping gun (400 °),oven ,heat source
- Needles for cleaning the nozzle, caustic soda
Procedure: Switch on the printer and set the highest possible temperature. Hold the heating cube and unscrew the nozzle very quickly (it’s hot!). Expose the nozzle to the 400 ° C+ temperatures(on the stove, oven, heat gun), occasionally passing the needle to remove every kind of debris. Try to clean it also from internal and external residues with a simple paper towel. Once finished, put a few flakes of caustic soda in a glass or any other glass container and insert the nozzle and pour a little water. Stir carefully until completely dissolved and let rest 8 hours.
On your return, the nozzles will be new.
How to understand if our cleaning has been effective
If you aren’t sure if the cleaning has been thorough enough, just look through the nozzle towards a light source. If we see a nice round dot of light we will have done a good job, otherwise, the procedure will have to be repeated.
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