[3D Printing for Beginners] Avoiding Common 3D Printing Nozzle Clogs - Cleaning and Maintenance Guide

In fused deposition modeling (FDM) 3D printers , many parts play crucial roles in model creation, but the nozzle is one of the most important. The nozzle is critical because it affects the printer's extrusion; if it malfunctions, it can lead to a range of printing problems. Furthermore, not all nozzles are created equal. Material, diameter, and other characteristics determine their performance and lifespan.

Nothing lasts forever, and nozzles are no exception. Over time, they degrade, especially when they become dirty, clogged, or overused. Therefore, it is crucial to clean the printer nozzles regularly and ensure they function properly along with the other hot-end components of the printhead assembly. Doing so can extend the lifespan of the nozzles.

In this article, we'll explain how to clean nozzles and prevent problems, as well as how to fix issues that might cause your 3D printer to stop working. We'll also provide some considerations when choosing replacement nozzles to avoid selecting nozzles that are unsuitable for your printer.

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How do I know when my nozzles need inspection and maintenance?
Below we list several problems that may be caused by dirty nozzles:

1. No First Layer <br>If you start printing and find that no filament is being extruded from the nozzle in the first layer, this could be due to a clogged nozzle. However, it's worth checking if the problem is caused by the extruder , Z-axis offset settings, or an unleveled print bed.

2. Nozzle pulls away printing material <br>This refers to the situation where, after the nozzle extrudes some material, it accidentally carries away the freshly extruded material during its movement. Usually, the nozzle is one cause of this problem; other factors include ensuring the Z-axis offset is correct and the print bed is level.

3. Hot End Blockage <br>Hot end blockage usually looks like the wire is stuck in the middle and lower areas of the hot end . Since the nozzle is part of the hot end, it can be the cause of the blockage, but the hot end path (such as the PTFE tubing ) should also be checked.

4. Inconsistent Extrusion <br>Inconsistent extrusion often appears as the printer failing to maintain uniform material extrusion. When the material should be extruded evenly, it suddenly bursts out in bursts. However, ensure this problem is not caused by wet wire or the extruder's stepper motor (especially its power ).

5. Incomplete Extrusion <br>Incomplete extrusion is a type of inconsistent extrusion, characterized by noticeable missing parts in the printed object. Also check if the problem is caused by damp wire , loose extruder tension , or an uneven wire path.


First and foremost, it's crucial to determine that the problem is caused by the nozzles!!! While cleaning the nozzles is generally not a bad idea, it might not solve the problem you're experiencing. A good way to effectively troubleshoot printing problems is to consider every potential cause of the issue. Then, check each possible cause one by one, from the easiest to the hardest, to find the real culprit.

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Once you are certain that the printing problem you are experiencing is caused by a dirty nozzle, you can proceed with the cleaning process:

External debris

Debris outside the nozzle is the most noticeable of all nozzle problems. This debris is usually excess molten material that sticks to the nozzle during the printing process. This problem is almost always due to the nozzle being too low, typically occurring during the first layer of printing. The problem is exacerbated because material is most likely to stick to itself. Basically, as the filament flows out of the nozzle, some of it sticks to the sides of the nozzle, and as the filament continues to flow, more filament sticks to the material that initially stuck to the outside of the nozzle.

Solution

First, clean the nozzle by wiping it with a damp cloth or alcohol while it's heated. This may produce some steam, but it does remove any material stuck to the nozzle. If that doesn't work, you can also use a wire brush, knife, or needle to remove any remaining debris from the nozzle.

While this cleans the outside of the nozzles, it's best to prevent material from sticking to them in the first place. Therefore, consider increasing the Z-axis offset and leveling the printing bed. Additionally, using a protective sleeve or silicone sleeve that covers most of the nozzles can also prevent excessive material from adhering to them.



[Congestion]

Clogging is perhaps the most common nozzle problem. There are two types of nozzle clogging: partial clogging and complete clogging . As you might imagine, complete clogging is the most serious type. Debris completely blocks the outlet orifice, causing the wire to get stuck in the extruder. Partial clogging occurs when debris only blocks part of the outlet orifice. While not as serious as complete clogging, you should clean the nozzle if either type of clogging occurs.

Solution

There are several ways to remove nozzle blockages, and we will introduce three. The first and simplest method is to use a small needle or drill bit (for example, a 0.5 mm drill bit for a 0.6 mm nozzle, or an even smaller needle or drill bit for a smaller setting) to insert into the nozzle, break up and push away the debris.

The second method is cold drawing, which completely removes debris from the hot end.

The third method is to completely replace the clogged nozzle. This method is relatively simple if you are using a general-purpose brass nozzle, as they are inexpensive. For this method, first heat the hot end to melt the solidified material clogging the nozzle. Simultaneously, ensure that the wire already fed into the extruder is removed.

Once the clogged wire has softened due to heating, unscrew the nozzle from the hot end. Before installing a new nozzle, be sure to clean the hot end with a small metal rod or pick to remove any excess wire adhering to the assembly.



[PTFE tube hot end gap]

The gap between the PTFE tube and the nozzle tip can also cause problems. Gaps can occur if the PTFE tube end is uneven, the tube is not pushed deep enough into the hot end, or the nozzle is not screwed in enough into the hot end to be flush with the tube.

If a gap exists, the molten wire will fill it. When the material cools, it will completely block the hot end. This happens in both PTFE liners and all-metal hot ends.

Solution

First, remove the PTFE tube from the hot end (if possible), then screw the nozzle in almost completely (approximately 95%). After confirming that the PTFE end is flat and the PTFE connector (securing the tube) is tightly screwed into the hot end, insert the tube into the hot end.

Finally, screw the last bit of the nozzle into the hot end to achieve a tight seal with the PTFE tube.

Replacement and upgrade

If none of the above solutions work, or if you suspect that the nozzle has deteriorated significantly and cleaning is ineffective, then it may be time to replace it with a new nozzle.

Nozzles vary in material, diameter, and other factors. These characteristics affect the nozzle's processing capabilities and the printing results. For example, abrasive materials such as luminescent materials or wood-filled materials can significantly accelerate the degradation of low-quality nozzles.

Nozzle diameter

While you may print a variety of different things, if you primarily print specific models or focus on a level of detail, then a key factor for a new nozzle may be its diameter.

0.2 mm
A 0.2 mm diameter exit hole is among the smaller sizes, allowing you to print more delicate items. This is an excellent size for printing miniature items. However, it should be noted that such printing takes longer and is generally less intense due to the greater number of print lines.

0.4 mm
A 0.4 mm diameter is the industry standard for consumer-grade 3D printers. This size offers a good balance between detail, strength, and printing time.

0.6 mm
If you are printing on special materials such as carbon fiber or fiberglass filaments, we strongly recommend using 0.6 mm diameter filaments! This can reduce the risk of printhead clogging.

0.8 mm
This diameter nozzle belongs to the larger category, allowing you to print at a faster speed. Printed items should also be more powerful due to fewer print lines, but this comes at the cost of reduced detail.


Nozzle material

Just as the resolution of the model you print can determine the type of nozzle, the printing material you will use should also be taken into account.

brass

Brass is the most recommended and cheapest nozzle material. While very inexpensive, it typically has the shortest lifespan due to its rapid degradation. Brass nozzles are best suited for printing on non-abrasive materials such as PLA, ABS, and PETG. However, when used on abrasive materials, the degradation rate of this nozzle material accelerates significantly.

Recommended brands: Ultimaker , Snapmaker , BCN3D


Hardened steel and stainless steel
Steel nozzles (including hardened steel and stainless steel) are a grade higher than brass nozzles. Nozzles made of this material are more expensive than brass nozzles, but have a longer lifespan and a higher maximum temperature. Besides non-abrasive materials, steel nozzles can handle lightly used abrasive materials before significant degradation, such as:

Reference Brand: Bambu Lab


Bambu Lab Hardened Steel Nozzle Series Bambu Lab Stainless Steel Nozzle Series

*The image above is for X1 and P1 only.