Jump to content
Ultimaker Community of 3D Printing Experts
Sign in to follow this  

What works best with cleaning an ultimaker hotend nozzle ?

Recommended Posts

What works best with cleaning an ultimaker hotend nozzle ?

Hi guys.

Yesterday after work I received in the post a few acupuncture needles.

I wanted to see how they would work with cleaning out a blocked hotend nozzle.



Up to then, I had always used small syringe needles to poke carefully up my nozzle and clean out and gunk and muck...


So this is what I found out:

The diameter of the acupuncture needles is perfect for the standard .4mm nozzle that comes with ultimaker BUT.. the problems is:

(1) The needle metal is very weak and prone to snapping, I lost some needle in one of my nozzles last night.. :sad: not good :sad:

(2) The acupuncture needle is very long, roughly 40mm to 50mm and with a small amount of excessive pressure, will bend and snap in one second..

(3) if the nozzle is jammed with something a little harder than PLA.. for example I purposely blocked my nozzle with woodfill PLA last night to test, when the woodfill PLA blocks,, it turned into a weird black woody cement.... the acupuncture needle snapped into a million pieces before it even tried to push this stuff out.

So... a few conclusions if your nozzle is blocked up... I would not recommend long form acupuncture needles !!


What does seem to work A LOT LOT better is a short

Disposable Syringe Hypodermic Needles

What makes these guys work a lot better is.. the quality of the needle metal is better. It is also hollow in the middle. so the shape of the tube makes it even stronger.. also the needle is not so long and so not so prone to bending and snapping. Also because there is a small plastic base.. it is easier to grip with the hand.

Here is an ebay link to what I mean :smile:




Ian :smile:


Share this post

Link to post
Share on other sites

ps... one other thing I learned... if someone uses for example woodfill PLA.. that stuff when burned up in your nozzle can be really troublesome to get all out... if you carefully take your nozzle off when the heating block is warm (240) drop it into hot boiling water, then take it out after a few minutes and you can pull out a lot of the gunk from inside..

IF !! that does not get everything... before you through your lovely nozzle in the bin... get yourself a .4mm drill bit and from the top, carefully bore down slowly, if you hold your hand steady and straight down.. you should be able to bore out the last debris of the burned woodfill and have a nice clean working nozzle again... its just a pity to waste a lovely hotend nozzle isnt ? :-) (remember. never try and bore out the nozzle from the thin top where the plastic comes out.. the change of breaking the opening is way to high ! )



Share this post

Link to post
Share on other sites

I got myself one of those "cleaning needles for camping stoves" (i don't know the english expression for this. They look like this https://media1.globetrotter.de/products/169x169/i69256.jpg

and cost 3€. They did a great job until i discoverede that you could also use a scratch brush for this purpose. You can clip off one wire. It is strong and flexible material that is okay for cleaning the nozzle orifice and the rest of the brush you can use to clean the outside ;-)


Share this post

Link to post
Share on other sites

My Ultimaker De-Clogging Nozzle Guide

Screen shot 2013 12 03 At 20.46.14

I've had my Ultimaker One for over 6 months now and have had a clogged nozzle on four or five occasions. To be honest it's been a pain to clear it. I've looked at the following guides and have found them helpful:







I’ve tried the 'hot pin/needle' technique but this was a pain as I had to manually file down a needle with wet and dry paper and I also manged to damage the tip of the nozzle.

I should mention that is it worth trying some of the approaches above especially heating the hotend to 250C and manually extruding filament through the hotend - but if you've got a grain of sand or other material stuck in the nozzle then heating the hotend to 250C isn't going to solve the problem.

I have devised a set of procedures which I would like to share - in part based on some of the procedures noted above.

First you will need to get together the following tools.


Screen shot 2013 12 03 At 20.46.06

1 set of pliers


Screen shot 2013 12 03 At 20.46.01

1 plumbers gas torch

Screen shot 2013 12 03 At 20.45.55

1 10mm socket for an electric drill. Make sure you use a very low torque setting otherwise you will thread the aluminium block - uber pain to replace.


Screen shot 2013 12 03 At 20.45.49

A short offcut of un-extruded PLA filament - 20cm will do.

Next, heat the hotend to 200C and then partially dismantle it so that the existing filament can be removed.


Screen shot 2013 12 03 At 20.45.44

Any spare filament in the PEEK can be pushed out with a suitable sized wooden stick ( I use a barbecue stick) or nail as suggested by http://www.tridimake.com/2012/10/clean-hotend-and-nozzle.html

If after this you still have a clogged nozzle and you can't see daylight through the nozzle then you will need to remove the nozzle.


Screen shot 2013 12 03 At 20.45.37

No daylight visible? - time to remove the nozzle.

I found the best way was to use a 10mm socket in an electric drill and a pair of pliers to hold the aluminium block. This is easier if the hotend is at 200C.

Once you've removed the brass nozzle, the next stage is to heat it vigorously, burning off the blockage inside. Hold the brass nozzle using the pliers and play the torch flame over it for 2 or 3 minutes until the blockage has burnt away.

Being careful not to touch the very hot nozzle, check if light is visible through the hole in the nozzle - if not, repeat heating with the torch and maybe heat for a little longer.

Once the blockage has burnt away you will see some light through the nozzle. The next stage is to ensure you have removed the burnt ash like reside from the inside of the nozzle.

The best way I have found to do this is to cool the nozzle down in water and then reheat with the flame for approximately 10 seconds. Then push the offcut of PLA filament through the larger threaded end and keep pushing until you see a thin stream of filament oozing out of the nozzle tip. If not remove the PLA and repeat the heating process.

Now to make sure absolutely no residue from the heating/burning is left inside, pull the solidifying PLA back out of the nozzle. The trick here is to get the nozzle/PLA to right temperature - this is difficult as the nozzle is no longer inside the Ultimakers heating assembly so there is no way to check this accurately. My approach was to cool the nozzle/PLA in water again. Now the PLA will be solid and it shouldnt' be possible to pull it out.


Screen shot 2013 12 03 At 20.45.28

The next stage is to gently heat the nozzle - a few seconds in the flame should do. If you make sure you don't overheat the nozzle/PLA at this time, you ought to able to pull the entire PLA stub out in one go. See photo below where all the burnt residue and filament inside the entire nozzle component has come out in one piece.

Screen shot 2013 12 03 At 20.45.21

Check the nozzle against the light. If you can see a clear circular hole, then congratuations - you've cleaned your nozzle.


Screen shot 2013 12 03 At 20.45.15

Be careful when reassembling the nozzle in the aluminium block to make sure it goes in at a straight 90 degrees - otherwise you run the risk of damaging the aluminium block. I would suggest heating the brass nozzle for 10 seconds in the flame again before screwing back into the assembly.

Take care at all times to handle the nozzle with a pair of pliers or wear proper gloves - otherwise you will burn your fingers.



Share this post

Link to post
Share on other sites

gr5 - you may well be right about this - personally I try to avoid the final - 'removing the nozzle stage', if I can, as I find the whole drill / burning flame thing a bit of a performance - especially as I can't get the drill head in position with the nozzle in place - hence the taking apart phase above. I guess I should try to find a reliable manual way (i.e. spanner) to remove the nozzle - it just gets a great deal trickier when the thing is hot - two sets of pliers are needed along with ideally a second pair of hands. Plus there's the problem of getting the nozzle back in the aluminium thread perfectly - not so easy to do I find - a big drill helps here for some reason.

FWIW - I've had so many problems with clogging that I ended up knackering both the brass nozzle and the aluminium block. Replacing the block was a big hassle especially removing the heater cartridge.

While I am a fan of the Ultimaker 1 design - I do think an easier way is needed to clear all these frequent nozzle blockages.

I would be interested to know if the UM2 design makes this any easier....


Share this post

Link to post
Share on other sites

Plus there's the problem of getting the nozzle back in the aluminium thread perfectly - not so easy to do I find

I've only done this step cold and just use my fingers.

I would be interested to know if the UM2 design makes this any easier....

Ha! I don't think so. The nozzle and the heat chamber is all one piece. No clogs yet though. :)


Share this post

Link to post
Share on other sites

I find a small pair of pliers to hold the block, and a 10mm ring spanner for the nozzle - I only ever loosen the nozzle and then wear a pair of light gardening gloves and finger loosen the nozzle.

When I put it back on I heat the block and then lightly hold the nozzle against it to get heat transfer, and then finger tightening it in, with just a slight turn with the spanner and pliers.

I use a hot air gun to heat the nozzle - feels more controlled than the torch :)

When I drill out the tip I use a pin chuck to hold the drill. I drill a hole in some board the size of the nozzle thread and screw the nozzle firmly down on the board, which sits nice and square on my drill press.

Drilled out a 0.65mm in this way and it worked well - but demands a steady hand and good eysight!

Love the needle tip - have just ordered some as I am about to use woodfill for the first time!


Share this post

Link to post
Share on other sites


While I am a fan of the Ultimaker 1 design - I do think an easier way is needed to clear all these frequent nozzle blockages.



If your nozzle gets clogged frequently, then you're doing something wrong...

I've never had a clogged nozzle before, though I've only printed a few kilograms of PLA so far, no ABS and no low-quality stuff.

Very nice guide though! I hope I'll never have to use it - but when the time comes, I'll know what to do ;)


Share this post

Link to post
Share on other sites

How to clean out the nozzle of an Ultimaker 2 3D Printer

Here are a few helpful tips to help you quickly and safely clean your ultimaker 2 print nozzle.


(1) First buy yourself some of these great little strong syringes !


(2) Unpack your new secret weapon !



(3) Heat up your hotend using the control panel !


(4) When the hotend is heated fully. take the syring with your fingers and gently slide the pin up the centre whole of the nozzle... You should feel a little resistance from the blockage.. Gently push up with the syring and then move the syring up and down. Repeat this process and remember to take out the pin of the syringe after every time.. so the loosened material can escape the nozzle.

This whole process should take no longer than 1 minute !


(5) Then in the control panel... choose change material and extrude your new filament... wait until the filament really flows nice and smooth through the nozzle... when you notice that the filament is running well... end the material change mode..

Congradulations you have cleaned out your blocked nozzle in less than one minute !



Share this post

Link to post
Share on other sites

I had my first proper clog the other day and decided to take the head apart. Had to be done eventually to get some experience on it anyway (and I had to get my first burn from the hotend of course hehe). In my case it seemed like it was some sort of dust or fiber of some kind that clogged it.

When I manually stuffed filament directly into the hotend and put some extra force on it I could see it coming out of the nozzle and was then able to pull it out with my fingers, it reminded me a bit of hair you pull out of your drain. I then did the old "stuff filament in, let head cool down to 60-80C and then jank it back out"-trick to really get it clean.

I guess what I'm trying to get at with my ramblings is this. If the clog is due to foreign matter getting into the hotend I feel like jamming a needle up there is like putting a bandaid on the real problem. You're simply jamming the problem material back in there so that it can clog things up again later. Sure, you're probably getting some of it out, but all of it?

I dunno, that's just my opinion and luckily I only have experience from a single clog so I might be wrong.

Oh and I have to say that taking apart the UM2 head is sooo much nicer than the old one.


Share this post

Link to post
Share on other sites

I think pushing dirt back with a needle, is not the solution indeed. Better remove the filament feeder hoze (or whatever kinky name it has). Then heat up the nozzle and forcefully feed it with some filament from the top of the print head manually, until filemant comes out like it should.

This worked for me and takes no more than a few minutes.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Our picks

    • Ultimaker Cura | a new interface
      We're not only trying to always make Ultimaker Cura better with the usual new features and improvements we build, but we're also trying to make it more pleasant to operate. The interface was the focus for the upcoming release, from which we would already like to present you the first glance. 
        • Like
      • 114 replies
    • "Back To The Future" using Generative Design & Investment Casting
      Designing for light-weight parts is becoming more important, and I’m a firm believer in the need to produce lighter weight, less over-engineered parts for the future. This is for sustainability reasons because we need to be using less raw materials and, in things like transportation, it impacts the energy usage of the product during it’s service life.
        • Like
      • 12 replies

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!