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eric-lester

Nozzle Clogged and Filament Stuck

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So I recently got an UM2 and have been loving it. I was printing a series of small parts with it today with no real issues, but I realized that I had selected the wrong part, so I aborted it and restarted with the correct one, but this time (out of nowhere and in a span of around 45 seconds) it seemed to be badly clogged. (e.g. it extruded small dots only and then nothing) I decided to stop, heat up the nozzle to 260 and see if I could extrude anything (as it seemed weird that it had just suddenly horrifically clogged with no material change and in no time idle). Trying to run material through of course caused the feeder to grind through the PLA enough to the point where it had no grip. I hope my predicament is clear:

I don't even know if the printer is clogged, and I have no means of removing it as I can't remove the bowden tube at the hot end because there's still filament there which can't be retracted as the filament is cut through right at the other end of the bowden tube...I'm really at a loss here. Basically, I have a stranded, possibly clogged section of filament stretching from the nozzle to the very start of the bowden tube on the feeder end. Any advice is greatly appreciated cause I'm completely at a loss.

 

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So the filament has cut right through at the feeder end and a full length stuck in the bowden tube - never heard that happening before - bad luck!

I reckon you're going to have to take off the feeder drive to allow you to then detach the bowden tube at both ends and slide it off to access the length of filament in there?

Once you can grab the filament - do an a 'atomic' nozzle clean to really get things clear.

Good luck

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don't see why you would have to take anything appart? just unlock the bowden at the side of the printhead, when you pull at it you'll end up with the bare fillament in the head, and you can directly do an atomic ...

although in a case like this with the stock feeder it might be smart to open the feeder for cleaning.

 

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It can happen when stopping a print that the last retraction occur and the filament cool down near the teflon piece getting stuck between the insulator and the top of the hot end.

Like Arjan said, remove the bowden clip (blue or red) on the print head, push down the white clip and pull the bowden tube off the print head. Normally you should be able to get the filament out of the print head.

If the filament is stuck in the bowden tube because of a blob at the tip of the filament then you will have to try and push the blob out of the tube in the direction that will be the shortest. Try not pulling it all the way through the tube because it may damage it.

 

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I have disassembled the entire print head, but I cannot clear the nozzle after several hours. How do I stick something into the nozzle hole from the front? Not even thin wire can fit. I have heated up the nozzle while the whole thing is disassembled and everything. There was a lot of gunk in there that I removed with several tools and filament etc, but the last bit won't budge. It must be a cone less than a cubic micrometre, but its immovable, even at 260 degrees. Any ideas?

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I'm understanding the problem the same way francfalco described it. Is that correct?

Assuming it is, disassembling the print head shouldn't be necessary. I would disassemble the extruder mechanism to free your filament from the back end, and cut your filament at the ground point (if it hasn't broken already). Remove the bowden clips and free the bowden tube at both ends by pushing down on the white clips and pulling the tube. If you're lucky, you should be able to slide the bowden tube off the filament and just work with the stuck piece (you might need a bit of force here).

Try the atomic method to clear your nozzle, it really is a lifesaver:https://ultimaker.com/en/support/149-atomic-method And repeat as many times as necessary to get the gunk off.

Good luck, I hope I understood your problem and that this works for you!

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Thanks, but as I said, I already tried all that for hours. If you can find a needle that thin that can stay firm, please let me know. Thin wire, a tenth the thickness of a staple is still far too big, and it does not hold it's strength. I tried compressed air from a spray can after the nozzle cooled down. I was scraping out gunk for hours with every type of electronics screwdriver, needle and wire that I had, melted in the filament like I said (this is the atomic method) about 80 times with 260>110 degree heat variations using ABS, then the other temperatures as explained with PLA etc, etc. Is there a household chemical that I could soak the heating element into or something? I need to clear this thing out.

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If you can find a needle that thin that can stay firm, please let me know.

 

Acupuncture needles are quite perfect for that purpose. Maybe there is a TCM shop or similar nereby your place? btw: If you show in your profile where you are located, people in your area might be able to give you more detailed advise.

Edited by Guest

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I would get it fixed under warranty before I started trying to source medical supplies to unclog the hole. I'll probably call for a replacement nozzle tomorrow. The hot print area was caked in burnt plastic inside the fan holder cavity behind the nozzle. That hole should be sealed better and is surely what led to the build up. Also, I suspect the design allows PTFE plactic to get pushed into the nozzle as it melts over time. This stuff is not designed to melt easily, I think. I'll bet everyone who owns an Ultimaker has increasingly streaky prints due to the PTFE tube holder breaking apart over time and blocking the filament passage. I would rather soak it in something that I have lying around the house though. Coca Cola should work based on its reputation, but it actually is not as acidic as people say - it has the same acid content as carbonated water apparently. Anyone able to think of a suitable declogger that I probably have in my kitchen or bathroom?

Edited by Guest

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Hypodermic needle - get them on ebay they are stiff enough to clear a .4mm hole (I normally warm the nozzle first).

Nozzle clogs are not common (depending on the filament and if it is left hot for a while).

I would think the dissolvers that you are looking at will attack the nozzle more than the plastic.

Stick to mechanical removal - needle, and then atomic while the nozzle is off. heat the nozzle and push filament in to test that you have cleared the opening.

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A great tool I use for clearing clogged nozzles are the twist-ties that come with plastic bags. I don't even strip off the plastic, just shove it into the nozzle with a pair of small pliers. Works a charm.

 

I tried that but the block was too hard and kept bending that wire. Then I went to buy a syringe but the idiot at the pharmacy told me she didn't sell printers so I walked out. Now this sounds like an ad, but I bought my Ultimaker2 from imaginables.com.au and I went and ordered a replacement nozzle for AU$66 (my warranty had just expired). They had it in my hand, delivered express within 12 hours, plus they threw in a new PTFE tube guide and a spring. Problem solved. The syringe was suggested by them too, but I was unable to get one due to my anger issues in regards to bad customer service at the pharmacy. 'But we don't sell printers!' Idiots. I'm pretty sure the tip of a small syringe would have unblocked it. I might need to do it some day, as it sounds like a few of you have had clogged nozzles beyond what the atomic method can clear.

Edited by Guest

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Maybe I should have bought that one, but as you all know with parts, a single solid part is far less likely to give you trouble than something that needs to be screwed together, especially at the trouble spot. I'm glad to have less options by owning a single solid nozzle. Ideally, they will invent a robotic aperture for adjustments rather than requiring manual nozzle replacements for altering extrusion thicknesses.

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I found out that the PTFE part is made of teflon, and it does not like to be in the nozzle. Replacing the nozzle is arduous - around 2 hours of trying to screw parts together that are not forgiving (its not made well for maintenance), but..

I finally replaced the nozzle and my printer is as good as new!

I recommend a new way of monthly nozzle cleaning. Atomic is only for easy to remove fragments.

Edited by Guest

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I bought some 0.4mm drill bits to remove any blockages in the nozzle hole.

If you heat up the nozzle to above 100C or so, then push the drill bit into the hole, you can push any junk upwards. An atomic clean then will get the bits out of the way.

The great care not to break the drill bit, they are VERY small.

Since switching to PLA it is now very rare that I get a blockage.

I have also fitted a wiper to the filament, just before it goes into the feeder. A small square of micro fibre cloth removes an amazing amount of bits and fluff from the filament, all of which would get into the nozzle.

 

I found out that the PTFE part is made of teflon, and it does not like to be in the nozzle. Replacing the nozzle is arduous - around 2 hours of trying to screw parts together that are not forgiving (its not made well for maintenance), but..

I finally replaced the nozzle and my printer is as good as new!

I recommend a new way of monthly nozzle cleaning. Atomic is only for easy to remove fragments.

 

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I found out that the PTFE part is made of teflon, and it does not like to be in the nozzle. Replacing the nozzle is arduous - around 2 hours of trying to screw parts together that are not forgiving (its not made well for maintenance), but..

I finally replaced the nozzle and my printer is as good as new!

I recommend a new way of monthly nozzle cleaning. Atomic is only for easy to remove fragments.

 

@zxen if you have a UMO it is a 5 minute operation

unless something is different on yours?

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Well on UMO+ it's more than 5 minutes, since you need to remove the aluminium cap, and the little tinny screws that hold half of it are a pain in the ass. Ofc it's not 2h when you get use to it, more like 15 minutes.

That's the video I used to learn how to fit the nozzles :D the most important think, that isn't explained on the manual, it's the part that shows to 'tight it' while hot. If you don't, there will be a leak.

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My friend had some ultra thin nozzle scraping things (less than 0.4mm) in his workshop. Now I can clean the nozzle anytime by sticking the reed in when the nozzle is hot and it unclogs everything without any disassembly. I don't know where he got it from, but if you can find one, you can unclog without disassembly.

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I now own an Olssen block with 4 nozzle sizes (0.4, 0.6, 0.8 and 1.0mm). I love it. Its how the next Ultimaker should be made by default. If anyone is able to find micro drill bits on the internet that are less than 0.4mm diameter, it will be an essential investment for your Ultimaker. I can assure you after days of disassembly and cleaning that if you simply:

HEAT UP NOZZLE TO MELT GUNK

STAB AT GUNK WITH 0.4MM MICRO DRILL BIT

then it will clear the blockage, no matter if its ABS or PLA.

What is happening inside, is that the plastic at the tip of the nozzle actually is melting when the nozzle is hot, but about 7mm higher it is not melting enough (its soft though), and the filament being pushed from behind cannot get past. This will cause your filament intake to grind a bite out of your filament at the back of your Ultimaker 2, so even if you do clear the nozzle, you won't know if its clear because the filament is not pushing due to this second problem. Therefore simply heat up the nozzle in maintenance mode (260 degrees Celsius) and stab into the nozzle hole. If you haven't already cut your fingers to pieces trying to get a safety pin, wire or a staple in there, I can tell you that they won't fit into the default 0.4mm hole. Nearly everything on Earth that is thin enough is too weak and will bend or break. You need to buy micro drill bits with a diameter of 0.4mm. That's ZERO POINT FOUR MILLIMETRES, not 4mm. Go and buy some from eBay right now. You need them if you own an Ultimaker2. Simple as that.

PS I bought Acetone but didn't use it or need it after I used the micro drill bits. Also, the atomic cleaning method didn't work for me at all after 14 hours of stressful attempts. Also note that the micro drill bits are guaranteed to break after one or less attempts so buy lots of them and simply let the broken pieces get pushed out with the gunk. Try to be careful to push up in a straight line to minimize the breakages.

Edited by Guest

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