Basics: Cleaning out a clogged nozzle!


We’ve all been there: A hotend that just
doesn’t seem to let any filament through. While there are a few different things that
could cause your printer to behave that way, a clogged nozzle is a likely cause and one
that you take care off easily. So today i’ll walk you through how to identify
a blocked nozzle and how you can easily fix it, often even without taking your 3D printer
apart at all. AprintaPro reached out to me for this sponsored
videos series to be featured on their PrintaGuide platform. Launching in January, it’ll be home to 3D
printing tips, tricks and guides. Check out AprintaPro and the PrintaGuide site
at the links in the video description below! A clogged or partially blocked nozzle is usually
fairly easy to make out: If your extruder motor is struggling to push material through
the hotend or you’re getting prints that are mostly air with only very little material
making its way down, then it’s a good idea to check the nozzle. While disengaging your extruder form the filament
by pushing the idler lever back, try and push filament through the heated hotend by hand. You might get an initial amount of material
making it through, but you’ll find that it’s either impossible to push or that the
extruded material curls heavily right after leaving the nozzle or extrudes much thinner
than what you might be used to. This can indicate a small particle stuck in
the nozzle bore, which we’ll need to get out. Somehow. One of the easiest, but also least reliable
ways is to grab a wire or an acupuncture or hypodermic needle that is small enough to
fit up the nozzle and try and get the blockage unstuck. Obviously, you’ll need a needle or wire
that is small enough to fit your nozzle bore, typically 0.4mm, and while some users recommend
using a drill bit instead, i’d actually say not to use one, since they are expensive,
break more easily than a solid needle, and worst of all, can permanently damage the nozzle
if you’re not super careful. So as a first try, preheat the nozzle to your
regular printing temperature and get cracking with that needle. Still being careful not to burn yourself,
your goal is not to extract the blockage, but only to break it up enough so that it
slips through the nozzle the next time you push filament through. You might have to go through the cycle a few
times of fiddling with the needle and pushing through a bit of filament by hand to check
if you’ve broken up the blockage enough. Another way that I personally prefer over
pushing needles up the hotend, is to use a cold pull – Ultimaker calls this the “Atomic
method”, which is similar in concept. A cold pull works best with slippery, soft
materials – so, Nylons, like Taulman’s Bridge filament. Again, heat up your hotend to the working
temperature of your Nylon or Polyamide filament, push it through the hotend as far as possible,
ideally, until your previous material is cleaned out, which obviously is going to be somewhat
hard if your nozzle is, like, completely stuffed, and then have the hotend cool down. Now, what i like to do after that is to set
the hotend to 110, 120°C and just keep on pulling on the filament while the hotend is
heating until the filament plops out in one piece. This should leave you with a perfect negative
shape of your hotend’s and nozzle’s bores and you will be able to see the contaminant
on the end of the filament. Then cut off the contaminated end, fully heat
the hotend again and repeat the process until the pulled end of your filament comes out
clean and you’ve restored good flow through the nozzle. Usually, two or three passes should be enough. Now, what Ultimaker recommends is actually
setting the hotend to a fixed temperature, 90° for PLA, 110° for ABS, waiting until
the hotend is at temperature and then yanking the filament out. This works fine for Ultimakers, but the keep
in mind that both ABS and PLA aren’t flexible enough to be pulled out cold from many other
hotend geometries, including the common E3D v6 setup. Nylon works fine for this. Now, if both of these methods don’t get
your nozzle unclogged, you can always go a step further and clean the nozzle outside
of the printer. Click up here to learn how to remove your
hotend’s nozzle safely, but if you’ve got the option to, do a cold pull first to
empty out as much material from the nozzle as possible. With the nozzle removed, you have the choice
of either removing the gunk mechanically or by using solvents. For mechanical cleanup, it’s the same idea
as with the nozzle installed – heat it up, e.g. with a hot air gun set to low, and then
carefully scrape out as much of the contaminant as possible using needles or other pointy
tools. When using hardened nozzles, be very careful
not to overheat those, as they will lose their hardening if you do. What also works for many materials is simply
burning out the nozzle with a blowtorch. However, if you’re unlucky, you might end
up with a nozzle that is completely FUBAR, so i’m not going to recommend this. But if you’re using ABS or PLA, you can
actually chemically dissolve most of the plastic remainder in the nozzle. For ABS, acetone or more aggressive solvents
work well, and PLA somewhat dissolves in ethyl acetate. So leave the nozzle in those for a few hours
and you should be able to much more easily clean out out the bore. If you can, go for a squeaky-clean look with
the bore completely freed up. Now, if these methods didn’t get your extruder
working perfectly again, you should also check the teflon liner inside the hotend if your
printer has one, and give the extruder a good staredown to see if it’s grinding through
filament because the hobbed gear is clogged up, dull or from the filament being kinked
and crooked inside the extruder. So now that you’re left with a functional
hotend, how do you prevent it from clogging up again? My printers have been running blockage-free
for many years now, and it’s just a few simple things:
First off, use decent filament. There’ve been reports of steel balls contained
within dirt cheap filament, and those, of course, are guaranteed to completely block
a nozzle in a heartbeat. Also, better filament is usually made in a
cleaner environment, which means it’s only going to contain components that will actually
melt in your printer’s hotend. The same goes for your 3D printer’s environment:
Keep it clean and dust-free. If your printer sucks in dust or other particles,
those can accumulate and easily clog the nozzle over time. If you’re uncertain about whether your workspace
is clean enough, you can simply use a bit of foam with a hole punched through to wipe
off any dust before it enters the printer – you’ll be surprised how much that actually
catches over time! And lastly, don’t cook your filament inside
the nozzle. If you leave the hotend heated up for an extended
period of time, chances are the filament is going to slowly decompose into an unextrudable
mess. So simply turn off the hotend when the printer
is idle. Some machines actually do this on their own. Alright, so i hope this video is helpful to
you. If you liked it, give it a thumbs up, consider
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and I’ll see you in the next one.

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