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kbtwining

Material not feeding through

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I have an ultimaker 2 that I've been using for over two and a half years now.  I am a teacher at a junior high and I typically use it to just print out random things for students for rewards in class.  They find some cool stl files on thingaverse and I print out a copy of it for them.  This year I have been having quite a bit of trouble with it.  Once the print gets past the beginning stage, everything seems to work fine.  But most of the time the material gets hung up in the feeder and doesn't end up coming out the nozzle.  I am using PLA material.  The print will start, and some material will get put down, but then after one or two passes, the material stops flowing through.  At first I thought the nozzle was constantly getting clogged, but then when I tried to "change the material," I noticed there were points were the feeder had worn through the material trying to feed it through the nozzle, but it wasn't moving.  When I pulled the material out, cut off the offending indented part, and put it back in, the print would work just fine.  The problem is I have to do this with nearly EVERY print.  Do I increase the material flow?  Increase the temperature?  Is the PLA material being nearly three years affecting its performance?  Thanks for any suggestions.

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Hi kbtwining,


 

Welcome into the Ultimaker Community. 


 

You made a very good description of your problem and it seems to be a known problem..

After reading through your post, we'll be very interested to know how is your PLA filament behaving after 3 years of storage? Does it become brittle and break off with a "snap"?

This is typically for old PLA that's been attracting some humidity over time.

What's happen is that the PLA tend to break inside the bowden tube, but still will be feed all the way through the tube and to the extruder. However; between the end of the bowden tube and the coupler (the white Teflon adapter you see inside the spring at the extruder), there is a little gap and at this place the filament tend to hook up preventing anymore feeding. 

So, do not change anything but just have a new fresh roll of new PLA and do another try.

PLA have to be stored in a "controlled" environment; humidity as lo as possible, normally less than 17% humidity and in darkness. However, this is another topic.. 

 

 PLA can be renewed to some level, -but again another topics.

 

Good Luck.


Thanks

 

Torgeir.

 

 

 

 

Edited by Torgeir

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Hiya and welcome. 

 

I would be inclined to follow the blocked nozzle route.  it may not be fully blocked but just old material layering around the inside.  there are two things possibly three to try and resolve this issue. 

 

1.  poke the nozzle hole with a strand from a wire brush whilst it's hot and dialing the manual feed.

 

2.  position the print head in the front right corner and heat up to 210 deg.  using pliers force some cut off pla down the hot end.  not too much force though as the axis may pop out. (just place the rods back in.)

 

3. replace the nozzle with a brand new one.  after 2-3 years it may be due a change anyways.  check out 3dsolex and give the ruby a try. pretty decent. 

 

hope this helps 

 

Bex

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Also to check if the printer is old and runs a lot, is the teflon isolator, after sometime it deforms and makes iy harder for the filamentt to pass through.

 

You can find how to check this in the ressources pages of the website (not easy for me to copy paste the link as im on phone)

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Here is a link to the guide I use for replacing the nozzle. Its the Olsson version, but works for the original nozzle as well and helps with the Teflon tube:

https://www.youtube.com/watch?v=-1Nh0snHLYw

 

After some 2 years plus of good printing on the UM2 I have also just started getting gaps between lines, a lack of cover or pillowing on final layers and other under extrusion problems. I changed the Teflon part first but this did not fully solve it. Finally replaced with a new Olsson nozzle and it did the trick.

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16 hours ago, Torgeir said:

 

Torgeir,

I haven't yet gotten any new PLA for my machine and my spool is pretty low.  I was planning on getting some new PLA anyway.  I've gotten quite a few good suggestions, but I think I'll do what you said first- order the new PLA and see if that makes a difference.  The material only snaps after bending it significantly.  I don't think it is too terribly brittle, I am in Salt Lake and it is pretty dry here, but I'm willing to try a new spool to see if it works.  Thanks for the advice.

 

-Kurt

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16 hours ago, rebekah_harper said:

Hiya and welcome. 

 

I would be inclined to follow the blocked nozzle route.  it may not be fully blocked but just old material layering around the inside.  there are two things possibly three to try and resolve this issue. 

 

1.  poke the nozzle hole with a strand from a wire brush whilst it's hot and dialing the manual feed.

 

2.  position the print head in the front right corner and heat up to 210 deg.  using pliers force some cut off pla down the hot end.  not too much force though as the axis may pop out. (just place the rods back in.)

 

3. replace the nozzle with a brand new one.  after 2-3 years it may be due a change anyways.  check out 3dsolex and give the ruby a try. pretty decent. 

 

hope this helps 

 

Bex

Bex,

 

Thanks for the advice.  I too thought it was a blocked nozzle.  However, after stopping the print, when I try to go into the maintenance menu and have the machine feed through material, it will feed through ok.  I'm going to try some fresh material, and then if that doesn't improve things, I'm going to replace the nozzle.

 

-Kurt

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6 hours ago, nick-s said:

Here is a link to the guide I use for replacing the nozzle. Its the Olsson version, but works for the original nozzle as well and helps with the Teflon tube:

https://www.youtube.com/watch?v=-1Nh0snHLYw

 

After some 2 years plus of good printing on the UM2 I have also just started getting gaps between lines, a lack of cover or pillowing on final layers and other under extrusion problems. I changed the Teflon part first but this did not fully solve it. Finally replaced with a new Olsson nozzle and it did the trick.

Where did you go to get a new replacement nozzle?  What size do I get?  I'm looking at shop3duniverse.com and trying to figure out which one would be best.  Thanks for the video, it will be helpful if I end up having to replace the nozzle.

 

-Kurt

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Well there is my store of course, lol.  thegr5store.com.

 

But if your printer used to work fine and now it's grinding filament at the feeder, and you didn't slowly speed up prints or cool down prints or change layer heights over this time period then it's probably hardware and the most likely culprit is the white teflon part which does wear out.  It costs I think $18 from my store or fbrc8.com.  It's one of the few parts that is reasonably priced from Ultimaker because it is considered a consumable.

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Also if you are doing a lot of prints for kids, you might want to just stick with a 0.6mm nozzle.  You can do 50% thicker layers and it prints 50% wider lines for resulting prints twice as fast if your walls/shells are 1.2mm thick versus a 0.4mm nozzle and the quality is quite good.  See 1.2mm shell is 3 passes for a .4 nozzle and 2 passes for a .6 nozzle.

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1 hour ago, gr5 said:

Also if you are doing a lot of prints for kids, you might want to just stick with a 0.6mm nozzle.  You can do 50% thickerlayers and it prints 50% wider lines for resulting prints twice as fast if your walls/shells are 1.2mm thick versus a 0.4mm nozzle and the quality is quite good.  See 1.2mm shell is 3 passes for a .4 nozzle and 2 passes for a .6 nozzle.

What's the nozzle that comes with the ultimaker?  If I get a bigger nozzle wouldn't I need to change the settings in Cura and on the machine?  Do I need to buy the nozzle AND the teflon part?  

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I suspect you only need the teflon part to get back to normal.  But I don't know for sure.  If your printer is from before january 2016 you probably have an integrated block where the nozzle is not removable.  It would be round.  If it has hexagonal sides like a nut then it can be removed.  Remove only when hot (150C is good) just in case some PLA is in the threads.

 

Once the nozzle is removed you can burn it out.  Or alternatively you can do a "cold pull" (google it) to clean the nozzle.  Almost always an old nozzle can be cleaned out assuming there is anything wrong with it.

 

Anyway if the nozzle is removable then I would consider getting a 0.6mm nozzle just because you are doing lots of prints and kids prefer larger prints.

 

But to fix your primary issue I suspect you only need the teflon.  If that's not it I have a list of about 20 things that can cause underextrusion or grinding and can post that here but really if you never changed the teflon - then it's time. Most people who do tons of printing change it every 3 to 6 months.

 

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Oh and if you have the old round nozzle style - then it's integrated with the heater block and you should consider getting an Olsson block while you are at it.  And to be safe strongly consider getting a new temp sensor as it's really tricky to get out the old temp sensor to move to the new block if you are installing an Olsson block (or block V3).  I am really good at it but my technique involves heat, WD-40, and most importantly - a sewing needle to dig it out without damaging the sensor electronics.

 

 

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On the older UM2s the most common cause by far is a worn out PTFE coupler as already stated by others. I'd like to tweak the recommendation on getting a new one though. I would suggest that you get the updated version used on the UM2+ which is called a TFM instead of PTFE coupler. Also order the spacer that goes with it and remove the spring you have now. This combo lasts a LOT longer than the old one and the difference in price is negligible.

 

Second most common thing is a clogged nozzle but it sounds like you've got that covered (although material coming out during the "Move material" procedure isn't a guarantee that it isn't partially clogged).

 

Another thing worth checking is that the fan on the back of the head is running. It should either turn on as soon as you turn the printer on, or after the head reaches ~42C. If the fan isn't running it can also cause similar problems where the first couple of layers work fine but then the heat in the head gets too high, the filament swells too high in the system and starts causing too much friction.

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What I would do in that case is:

 

- First do a couple of "atomic pulls" to clean het nozzle. Then you are sure there is nothing blocking the nozzle, and the inside of the nozzle is not totally covered in ashes which might hinder heat transfer to the filament. Also, by the shape of the molten part, you can also see if your teflon coupler is worn out: this will cause a sort of blob or lip deformation in the molten and cooled filament, near the edge between the brass and teflon part.

 

- If this blob or lip is present in the pulled out filament during atomic pulls, you definitely have to replace the teflon coupler. Using the old coupler, I had to do it about once a year, for printing mostly PLA. As said above, use the new version of the coupler.

 

- If the PLA is old, it will get stiffer, and more difficult to unwind from the spool: it acts like a very strong spring that resists unwinding. And it causes a lot of friction in the bowden tube and in the nozzle. These all contribute to underextrusion. A simple solution is to manually unwind a bit of filament, bend it around a skater wheel (7cm diameter) in the *opposite* direction, so it straightens out. Then unwind and straighten the next 15cm, etc., until you have done a few meters. This only takes a few minutes, and I do this while the printer is warming up. Then wind it up on the spool again loosely, so that the bending radius now is about 30 to 50 cm, instead of 10cm before. For the old UM2 printers (non-plus version), this helps a lot.

 

- For a more gentle atomic method to clean the nozzle, see my manual at: https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/

This does not require brutal pulling, but only gentle wiggling and rotating, and deeper cooling.

 

- With compressed air, clean the feeder wheel from dust and debris, so you get good traction.

 

These things will most likely get you going again, I think.

 

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I had the same thing happen as described in the OP and it turned out I had a lot of friction in the bowden tube. Over time, debris from the feeder had gotten into the tube. Took out the tube, cleaned it with some thick wool, added a bit of graphite and everything was good again. You might just want to inspect your bowden tube whether you can see tiny pieces of filament near the feeder end. If you can, open the feeder, pull out the filament at about 90* and check friction by moving the filament by hand.

 

 

Edited by aggertroll
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