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somerwil

Blocked nozzle

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Hi there,

after some initial problem I got some very, very nice prints from the Ultimaker 2! It finished some marathon prints last week resulting in a http://www.thingiverse.com/thing:164317 at 0,05mm. It looks awesome and the two pieces come together nicely.

After these print I changed the material (Colorfabb's Woodfill). I wish I didn't...

The material change was OK, material was flowing nicely without problems but during the first print, things went wrong. On the first layer I could see just a few normal lines but extrusion stopped pretty soon. The temperature was quite high at that moment (250) to see it the material gets through. I also choose a rather thick layerheight at 0,2mm.

Now, no matter what material I try to print or at whatever temperature I select, nothing comes through the nozzle anymore. I tried to go back to the Loggerhead's color and also tried a new spool. That, like I expected, didn't give any good results.

What's the best way to get rid of the nozzle jam?

 

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Heating the head hotter than normal - say 250, if you usually print PLA, and then carefully inserting a piece of thin but stiff wire - like a syringe needle, or bristly from a wire brush - is a good start. Be careful, as if/when the blockage clears, it may spit hot plastic out of the nozzle.

If the blockage is too big to fit through the nozzle at all, then this probably won't help, unless you are somehow able to break it up. But if it's jsut that something is lodged across the opening, then this might be enough to twist it to where it can come out.

If not, then you probably need to do some head disassembly, and try to fish the blockage out from the other side. But that's a pain - so try the simple upward poking approach first.

 

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I got dust on my filament and then in my UM2 nozzle and had to clear 4 blockages in 4 days and now have a recommended method - would take 1 minute if I didn't have to wait for the nozzle to heat up and cool down (minimum 2 heats, one cool).

The Atomic Nozzle Cleaning Method Simpler Version (July 2014)

(named after Mostly Atomic Bob who may or may not have invented it - not sure)

I do this method on EVERY FILAMENT CHANGE now. It keeps the nozzle clean I hope.

If you have no filament in the head, heat nozzle to 180C and while waiting insert the filament manually through the feeder, cutting the tip of the filament to a point first. You have to push very hard to get the feeder spring to move back but then it's easy.

1) Set nozzle temp to 90C. Wait for the nozzle temp to cool or heat to this value. If heating wait 10 seconds at this temp. Push the head to the front of the machine to reduce friction in the tightly bent bowden. Grip the filament firmly below the feeder and pull down. You should get a nozzle tip shaped end on the filament.

2) Pull the tip half way through the bowden and then pause 10 seconds. If this is your first time pause 20 seconds. This is to let the PLA cool below glass temp (to about 40C) so it doesn't come apart in the feeder.

3) Pull the filament all the way out. When it is getting very close do it in one fast swift motion so that the stepper is spinning with momentum and pushes the tip out.

If it breaks inside the feeder (happens about once every 50 times) instead of taking it apart you can get some small tools and push the roller away from the feeder sleeve with one tool while someone else digs around in there to get the PLA out. If that doesn't work take it apart.

4) Examine the tip for dirt, etc. Cut it off with two snips to make a chisel point. Re-insert through feeder into print head, set temp to 180C. You have to push pretty hard to get past the feeder spring. Wait for temp to hit 180C, push the filament into the nozzle and if nothing leaks out the tip go back to step 1. Repeat this procedure until the tip comes out clean and/or it starts working again. Inserting a needle through the tip may help but doesn't seem to be necessary.

The Atomic Nozzle Cleaning Method

(named after Mostly Atomic Bob who may or may not have invented it - not sure)

1) Remove filament (change filament menu item and just cancel after it's out)

2) Remove Bowden at print head. Follow instructions carefully - it's easy to scrape and damage the bowden on the metal blades.

2a) Remove the colored clip (red I think on mine) that holds the gray part up. I'll call the gray part the "bowden holder".

2B) Loosen the 4 thumb screws until they are about to dissapear into the bottom metal piece - until the ends of the bolts are flush with the bottom metal plate - this is to loosen upward pressure on the bowden.

2C) At this point the bowden should be able to move up and down (along with the bowden holder) freely. If not now you have to loosen the metal nut that has holes all the way around - rotating that lowers the nozzle reducing upward pressure on the bowden. I haven't messed with this yet.

2D) GENTLY raise the bowden while pushing down on the bowden holder. you do not want to pull very hard or you will scrape it. Consider pushing down a bit before pulling up. Look at it carefully when it comes out - there should be a ring where the bowden holder blades cut into it. If you do scrape the bowden you will need to cut off 2 or 3mm off the end of the bowden. Obviously you can only do this a few times before needing a new bowden tube.

3) Cut a piece of PLA filament to help you clear the nozzle - it should be 100 to 300mm long. Stick it into the nozzle from above - you should straighten it by bending it straight. Make sure the nozzle truly is plugged - when you get to the white nylon piece there should be resistance but it should keep going down.

4) At this point it is more difficult if you don't have a needle but probably not mandatory - hypodermic is good, or accupuncture or a .35mm drill bit, or a wire from the wire brush that cleans a barbeque grill, or some other metal brush, or a thick strand of copper from a power cable (this never worked for me - the power cable thing - much too small.

5) Stick the needle up into the hole and pull it out again - don't push on the filament.

6) Lower nozzle temp to 100C. At 90C pull hard up on the filament. This should hopefully remove your clog. Cut the end of PLA off and throw away that clog.

7) Raise nozzle temp to 180C. Insert PLA again and if it is working you are done and put it back together. If not go back to step 5.

8) If it isn't clogged but the PLA curls sharply (even with 30mm of freshly extruded pla pulling downwards) and touches the side of the nozzle, then there is a partial clog. Once your needle is in the head push hard in a circle to scrape the inside of the metal nozzle near the tip. Don't scratch the exterior of the tip of the nozzle. This clog should be able to go out through the nozzle so hopefully you don't need to cool the nozzle but instead can push the (smaller) clog out the tip.

9) REASSEMBLY - Remove your short piece of PLA and put the Bowden back in. Push it as far down as it will go and then tighten the 4 thumbscrews such that the bowden is in there tight. The little red clip should now do nothing - and the bowden holder should always be in the up position from now on. Also your retraction distance can be reduced from 5.5mm to 4.5mm (at least in my case). Maybe even shorter - haven't experimented much yet.

edited as per Illuminarti's suggestions below.

edit2: I changed the "pull up" temp to 90C as I've done this more times since I wrote this and 90C seems to be the perfect temp. 100C works but not as well.

Edited by Guest
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Couple of points... in the bowden removal section, you don't mention pressing down on the grey holder while pulling up on the bowden. If I do that, I can remove the Bowden without having to unscrew anything, on mine.

Secondly, at step 6) you say to pull hard up on the 'bowden'. I think you mean 'filament'. Or am I missing something?

edit by gr: I edited above with Illuminarti's suggestions.

 

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Hi there,

thanks for the tips again. The easy method didn't work for me but after disassembling the print head and doing the trick (heating up, push PLA in, cooling down to 90 degrees) a few times worked for me. It was some work and since the Woodfill gave a lot of mess in the nozzle I had to do this trick for about 5 times to get rid off all the black sticky stuff.

Happy it's printing again! :cool:

If there are so many people encountering problems on clogging, I would advice the Ultimaker team to come up with the best solution and place a video of the recommended method on their site/ Youtube/ whatever. Or is there any available yet?

Other question: Is printing in Woodfill difficult? As in: does it block the nozzle frequently?

Perhaps my temperature setting for this material was wrong (230 degrees). What's a good temp for Woodfil?

 

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Hmmmm, I feel a little uninformed here. Have I missed something or is this one of the 'things you should know'? On the Colorfabb's site it says 0,4mm nozzle size so that's either wrong of misleading.

I'm not considering drilling my UM2's nozzle to a wider diameter for now. Too happy it's working fine now (and making awesome prints!).

I think I'll sell my Woodfill spool (with 749,9 grams on it ;-)) so if anyone is interested, please PM me. I'm in the Netherlands.

 

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Personally I'm against removing the bowden tube as it risks damaging the tube (as gr5 pointed out). I know there are quite a few people that disagree with me on that but from my experience with pulling apart the head on the UM1 more times than I care to count and seeing the state the bowden tube is left in after a few times, well, I prefer not to do it.

I've only pulled the head of the UM2 apart once so far but I felt it was easy and quick to do and you get the added benefit of being able to really take a look into the nozzle and make 100% sure that it is clean.

Also, regarding step #8. Is that something you have confirmed, or is it a theory? The thing is that I've seen that curling with a freshly cleaned nozzle as well.

 

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Step #8 curling is from personal experience. But it wasn't typical curling. It was severe curling. Typical curling is when the fresh pla is extruded into air it curls and touches the tip. That's normal. Extreme curling is when: even after pulling the filament straight, and even after 30mm of filament is pulling straight down, you extrude some more and the curling power makes it touch the nozzle again. If you ever experience this you will know right away that something is very different.

Fixed in seconds with a hypodermic needle.

I edited #8 slightly (added the "even with 30mm fresh pla pulling downwards").

 

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I think I just hit murphy's law.

 

I have a blocked nozzle on my ultimaker 2.

 

 

 

First I tried this "Atomic method" that everyone is talking about.

 

 

 

It worked for a few times, and then the last time the nozzle jammed again, i tried it, only this time, the filament broke at the nozzle as I was pulling it up, and the pin i was using to clear the nozzle from below also broke IN the nozzle, leaving it further blocked at the bottom with a broken part of the pin, and blocked at the top with a filament that doesn’t melt even when i turn it up to 260 degrees.

 

 

 

What can I do here?

 

 

 

It’s been very frustrating. The nozzle has already jammed up on me like 10 times, ever since i got it 2 weeks ago.

 

 

 

Pics here:

 

https://www.icloud.com/photostream/#A35M7GFPa5Ej5

 

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Yes, that's probably going to be a problem. You probably need to heat it up enough to soften the filament a bit, and remove the collar and teflon part to get at the nozzle proper.

BTW, can you post some photos of your head assembly looking from the front and back as well, please?

 

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I don't have a UM2 but do have a UM1

Hypodermic syringe needles are so far the most reliable for me - they tend not to break.

It will sound daft, but I would think that you should heat up high and gently push another needle in after the pin - to properly push the pin into the chamber.

For the filament you can either heat a pin (fold over a paper clip), push it into the filament melting as you go down, and then wait to cool - then gently pull and it should help hoik it out.

it is going to take you time and be frustrating, but try and avoid anything sharp :)

James

 

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Needles can damage the teflon part so don't stick it very far into the nozzle.

garry, you are going to have to take it all apart.

If things are stuck you might need a hair dryer to heat things to around 80C. A heat gun will go over 300C which is too hot for some parts.

Start by loosening the 4 screws completely, remove the red clip that holds the bowden, push down on the outer ring and pull up on the bowden. It might be stuck due to filament but keep going.

Remove the 4 screws, loosen the side fans and let them hang. Remove the 2 screws holding the rear fan in place - be careful as there is a strong spring in there. Remove that spring and the white teflon piece (it might be stuck).

Remove the nozzle by rotating that ring with the 6 or so holes through it. The nozzle might need to be heated to around 130-180C to do this step. If you can get the nozzle loose, then let it cool, and remove that screw sticking out of it - or just loosen it enough so the heater and temp probe slide out.

Now it gets tricky to get the filament out. You need boiling water or a hair dryer or something that heats the PLA up to at least 80C to get everything apart and get the bowden out.

 

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A hint about dusty filament: if you wrap a pipe cleaner around the filament, it will brush off the dust.

Since i found that tip somewhere here on the forum, i've had a lot less blockages.

(Yes, i could also clean the place more often, but the pipe cleaner seemed easier :-) )

 

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That's more than I've done ever, in total. So you are probably the world expert! What temp exactly did you find the best to cool down to? 90C? 95C? And what is the minimum to heat up to? 150C? 180C?

 

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Hi All,

After trying woodfill I also fell into this trap. The leaflet in the box said something like "just use the same settings as you would with standard PLA as a starting point" -so I didn't even bother going online initially to look at hints - lesson learned.

However thanks to this excellent post I was back up and running after 5 or 6 cycles of the atomic method plus one small addition...

I got to a point where the pla was coming back up clean, but still couldn't extrude, so guessed that there was a blockage right up at the entrance of the nozzle. I tried a sowing needle initially but was a little worried about breaking it off, or damaging the nozzle and it still didn't seem to budge, so instead I took a different approach.

Using a piece of filament I pushed it up against the bottom of the heated nozzle (mind fingers!). So effectively pushing melted filament back up into the nozzle and dislodging the blockage, before feeding from the top again. It took a 2-3 cycles of that but it worked and the blockage came through.

I then proceeded to print woodfill at a 0.2 and 0.25 layer height and didn't have a repeat of the problem.

Cheers,

Greg

 

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I had a blockage last night using a sparkly PLA. Using a filament off-cut I used the method described above (Pushing PLA back up the nozzle while being careful not to burn myself). Presto! blockage gone, 5 second fix!

Cheers,

Greg

 

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Thank you very much, today I unclogged my UM2 nozzle using the simpler version method.

However, I have some questions

1) how do you push the head? Is there any menu to move the head x and y position in new firmwares?

what I did was using the "change material" to have the machine place the head at the front. Normally, at power on the motors are powered and stiff.

2)Similarly, when in the "heat nozzle" menu, the feeder is stiff (motor on). To pull the filament, once I was at 90 degrees, I switched the machine off, and manually pulled the filament. Is there a better way?

 

I got dust on my filament and then in my UM2 nozzle and had to clear 4 blockages in 4 days and now have a recommended method - would take 1 minute if I didn't have to wait for the nozzle to heat up and cool down (minimum 2 heats, one cool).

The Atomic Nozzle Cleaning Method Simpler Version (July 2014)

(named after Mostly Atomic Bob who may or may not have invented it - not sure)

I do this method on EVERY FILAMENT CHANGE now. It keeps the nozzle clean I hope.

If you have no filament in the head, heat nozzle to 180C and while waiting insert the filament manually through the feeder, cutting the tip of the filament to a point first. You have to push very hard to get the feeder spring to move back but then it's easy.

1) Set nozzle temp to 90C. Wait for the nozzle temp to cool or heat to this value. If heating wait 10 seconds at this temp. Push the head to the front of the machine to reduce friction in the tightly bent bowden. Grip the filament firmly below the feeder and pull down. You should get a nozzle tip shaped end on the filament.

2) Pull the tip half way through the bowden and then pause 10 seconds. If this is your first time pause 20 seconds. This is to let the PLA cool below glass temp (to about 40C) so it doesn't come apart in the feeder.

3) Pull the filament all the way out. When it is getting very close do it in one fast swift motion so that the stepper is spinning with momentum and pushes the tip out.

If it breaks inside the feeder (happens about once every 50 times) instead of taking it apart you can get some small tools and push the roller away from the feeder sleeve with one tool while someone else digs around in there to get the PLA out. If that doesn't work take it apart.

4) Examine the tip for dirt, etc. Cut it off with two snips to make a chisel point. Re-insert through feeder into print head, set temp to 180C. You have to push pretty hard to get past the feeder spring. Wait for temp to hit 180C, push the filament into the nozzle and if nothing leaks out the tip go back to step 1. Repeat this procedure until the tip comes out clean and/or it starts working again. Inserting a needle through the tip may help but doesn't seem to be necessary.

 

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I'm not sure what we are doing different but there are many possibilities. Many things turn the stepper motors on. They sometimes turn off after a few minutes. Here is my recommendation:

1) Turn printer off and on

2) Set nozzle temp to desired temp (I think it's: Advanced, config, nozzle temp - or something like that - I do it so fast now I don't read or think)

At this point all steppers are off so you can push the head around. Extruder motor is also off.

Often I do this kind of thing right after a print. Right after a print all steppers are also off.

 

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