3D Printer Extruder Nozzle Clogged? Here Is How To Unclog It

Steps and Tips to Clear a Blocked 3D Printer hot end

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One of the challenges I hear about quite often is what to do when the 3D printer nozzle gets jammed or stuck. I have experienced this only once and the fix was quite easy, however, I have wanted to share some of the solutions that may help you unclog a hot end.

Each 3D printer is different, of course, and the manufacturer likely has recommendations for clearing their specific printer nozzle that you will want to follow, if at all possible.

In general, here are some tips and some of the best tutorials I have found (if you have seen some others, please share them via social media or email – get in touch by clicking on my name in the byline above).

WARNING: Remember, read the fine print so that you do not void your warranty.

One of the best resources comes from Deezmaker, a 3D printer store, and hackerspace in Pasadena, California, that also created the Bukobot 3D printer. Founder and owner, Diego Porqueras, is often sharing in-depth posts and tips for not only his printer but 3D printing in general. His Nozzle Cleaning (under a Creative Commons license by-sa-3.0 unported, link at end) post is detailed and helpful and has inspired a great video walking you through the steps (listed after this section from Bukobot).

The safest and most effective way to completely clear the plastic from a nozzle, taking any contaminants with it, is what I call a “cold pull”. The idea behind the cold pull is to pull the filament out of a nozzle at a temperature cool enough to keep it in one piece (rather than leaving molten plastic in the hot zone), but still warm enough to allow the plastic to stretch enough to pull away from the sides of the barrel so that it doesn’t seize up entirely. This is easiest to perform with a polished-smooth stainless steel barrel, with those that have a PTFE liner all the way to the end coming in second, because nozzle pressure can slightly compress the softer PTFE and create a plug that will be difficult to pull out.

The cold pull technique has been successfully done with both ABS (this was the best material to use for a long time, with a cold-pull temperature of about 160-180C) and PLA (much more difficult due to its thermal transition properties, but a cold-pull temperature of 80-100C will sometimes work), but Nylon 618 from Taulman (pull temperature of 140C) is far easier and more reliable to use for this purpose due to its strength, flexibility, and low friction.

The video I mentioned above is here: How To Unclog 3D Printer W/O Disassembly (Taulman).

How to Quickly Clear a “Not-Too-Clogged” 3D Printer Nozzle

It could be that your hot end, or nozzle, just has a small amount of residue or material build up – sometimes you can clean it out with a probe. Some users recommend a thin wire, but that can scratch the inner wall of the nozzle, something you want to avoid.

The best material I have found is guitar string – it is rigid, but will not scratch the metal interior of the nozzle. If you need something more durable, or more rigid, some short pieces of wire from a brass wire brush can work if used carefully. Often, you are just trying to dislodge a piece of clogged plastic (ABS or PLA).

Removing and Cleaning the Blocked Extruder Nozzle

Again, depending on your 3D printer, you may have to remove the printer head and clean it. This short two-minute video from user “danleow” on YouTube is helpful: 100% Solved - Clean blocked extruder nozzle in 3D printing. He also sells a kit on eBay that some might want. He links to it from YouTube.

Signs of the blocked nozzle when the filament is not extruding uniformly, extrude very thin filament than usual or not coming out from the nozzle. What you need: Acetone, Torch, and very thin wire. Here are his steps:

Step 1: Soak the removed nozzle into acetone for about 15 minutes to clean out exterior dirt. Use a soft cloth to clean the nozzle.
Step 2: Place a nozzle on a stone and burn it using the torch for about 1 min. Make sure it is extremely hot until you see slight changes in the color.
Step 3: Use a very thin wire to clear the hole in the nozzle. If the wire cannot go through repeat step 2 again until it can go through. Do not force through the hole with the wire. You do not want to scratch/damage the internal wall of the nozzle. I use soft copper wire stripped from an unused phone cable.

 

Finally, the absolute most detailed resource I found is on MatterHackers where they explain: How To Clear and Prevent Jams on Your 3D Printer. Griffin Kahnke and Angela Darnall make it super clear:

“If you have a 3D printer, at some point you may encounter a filament jam. This guide is intended to help you prevent such jams, or deal with them as painlessly as possible.” Prevention is key! They explain how to understand what causes or can create jams in the first place, such as, nozzle height, temperature, tension, and calibration. They have some terrific visuals, too.

I am always on the lookout for new ways to solve 3D printer problems or improve a method of printing, so please get in touch by clicking on my name in the byline above.

Bukobot Nozzle Cleaning Post attribution: BY-SA-3.0