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maik-jaehne

erratic Underextrusion new UM2

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Hi there...

read a bit around due to I´m fighting with my UM2 since 2 weeks, after stick-problems with printing the 1st layer on the glas (I solved with a temperature around 230-245 for PLA) I still have underextrusion. I run the test "Tube" posted in the forum. Retraction seems to be one issue (see picture/link: http://fablabdd.de/?attachment_id=170373905)... I tried several PLAs (ColorFab, FormFutura, InnoFil, Orign.Ultim.,...) but not a big difference. Prints are not free from holes etc. More or less often I can hear the extrusion "click". I put my hand on the PLA just before it enters the extruder to see if it is the "Roll" problem but it seems to be not. I fastened this extruder screw (ca. 2 lines down) this helped a bit but did not solve to problem total.

As far as I understand there could be some burned PLA in the Nozzle/Print head but how to clean that? Also: it does not look like I have this teflon thing problem.I checked this after changing PLA.

So any suggestions? At which speed are you printing? I thought 70-90mm/s with a 0,2 should be not a problem but up to now it is... only 0,1 with 50mm/s works (sometimes) well.

Thanks, Maik

 

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I thought 70-90mm/s with a 0,2 should be not a problem but up to now it is... only 0,1 with 50mm/s works (sometimes) well.

 

90mm/sec .2mm layer is pushing the limits on a UM1. The UM2 is weaker as far as I can tell. .1mm 50mm/sec is much more reasonable. I've been printing .1mm 30mm/sec at 220C for most things. I know - it's slow - but it comes out nice.

There *does* seem to be some kind of problem with the UM2 extrusion rates, but it's very unclear what the problem is. Lots of people are working on it so I recommend you stay tuned. Unless you want to be the Hero who figures this all out. In the meanwhile, if you want pretty prints, it doesn't matter. Just print 30mm/sec, .1mm layer and 220C (or warmer).

Some of the thoughts of what the problem might be:

gunk in the nozzle - possible ABS from the black extruder housing

extruder issues including: weak stepper motor, filament rubbing much too hard against housing, bearing not spinning due to being too tight against outer wall, or inner pieces, white tension arm not applying pressure due to 4 extruder screws too tight, filament stuck on reel or coming in at too strong of an angle. Or it might be that different people have different issues.

6mm^3/sec is pretty damn good (although others get more). That's the equivalent of 150mm/sec at .1mm layers or 75mm/sec at .2mm layers.

No one has this figured out but even if it were fixed you probably still want to print 30mm/sec, .1mm layer and 220C if you want the most beautiful possible prints. Of course if you care more about functionality than beauty you are going to either figure it out yourself or wait a few more weeks until this is figured out. Or you can increase temp to 250C which is reasonable as long as you print at least 5mm^3/sec.

If you *do* want to experiment you might start with cleaning out your nozzle with a hypodermic (or taking it off), or printing at 250C for a few minutes to possibly get out any ABS, or you could try this experiment as it might lend something (who knows):

http://umforum.ultimaker.com/index.php?/topic/4222-pulling-force-of-um-extruder/?p=34887

 

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that explains a lot... I expected something else :(

 

90mm/sec .2mm layer is pushing the limits on a UM1. The UM2 is weaker as far as I can tell. .1mm 50mm/sec is much more reasonable. I've been printing .1mm 30mm/sec at 220C for most things. I know - it's slow - but it comes out nice.

 

Today I dis- and reassembled the extruder and the head to be sure there is no problem. I could not find anything... So I start with some speed test...(this test was posted in this discussion: http://umforum.ultimaker.com/index.php?/topic/3976-almost-always-missing-layers-underextruding/ I used the 0.1 Layer without retraction Version)

But with different filaments. I also pushed filament by hand if the extruder start slipping just to be sure It is not the holder or Filament curling issue. (It wasn´t)

Interesting results:

Ultimaker PLA runs best, at all speeds (but needs a temperature from 210 up to 230 degrees)

Colorfabb (Olympic gold) starts well at 220 and might work until "full speed" 10mm3/s at 260 degrees

InnoFil (Silver) works well but only at 230 degrees and 80% of 3mm3/s (so very slow) (at this case: increasing temperature does not help, manual push also not)

FormFutura (White) starts working at 230 (3mm3/s) need to go up to 250 at 4mm3/s and stop working at 5 to 6 mm3/s

Finally an last years igo3D orange start at 230, 4mm3/s runs at 240, but 5mm3/s at 250 does not work again...

So as you can see very different results... I did not expect such differences...

Nexts days I´d like to run some retraction or straight StickFilament tests.

Maik

(How can I add Photos here?)

 

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Hey Maik, to attach pictures follow these "easy" but numerous steps:

1. Click on the dropdown with your name at the top.

2. Select "My Gallery".

3. Click on the blue "Upload" button (top right).

4. Click on "Select album"

5. Select your album (provided you have one, but I guess it'll ask you to create one if you haven't).

6. Click on the blue "Choose Files..." button and select your files.

7. Click on "Review and publish".

8. Check the orientation of your images and click on the tiny bent arrow beneath a thumbnail to rotate it in place.

9. Click on finish or save (can't remember - should be obvious).

10. Return to your post (or if you have done this in another tab), click on the "My Media" button at the top of your editor window (when your write a post).

11. Select "Gallery Images" on the left.

12. Select the images you want to add in place (just one click adds a text bit to your post representing the image).

13. Click on finished (bottom right).

phew!

 

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The photos are very useful but ONLY if you add temperature. Could you please add the temperature you were printing at? If you changed temp throughout the print you could maybe post the final temp where it failed or show with arrow which layer it was at which temp.

Your post showing temperature and max print speed is very useful, thanks! I will be referring to it quite a bit!

10mm^3/sec is what I consider very fast. This test is designed to fail. The person who created this test probably didn't expect the printer to reach above 5mm^3/sec. I don't think the UM Original can do much better - many people can't print 10mm^3/sec on the UM Original.

 

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Sorry for the delay... but here we go.

at first the picture with some numbers added. I used this test cylinder from illuminarti. (test start with 30mm/s and add 10mm/s each 10 mm, so final is 100mm/s)

PLA dif. Sorts test with print temperature

I did a change to my U2. It now runs with that new extruder. The clicking noise disappear. And the first prints suggested I can print faster now. But: a test run with different materials and the test cylinder did not make such a difference to the original extruder. Under extrusion appear again but without the well known "click" of the extruder.

I tried the retraction test cylinder file... here the new extruder seems to have a significant influence. While prior the printing with retraction and Innofil material does not work - now it does - up to 40/50 mm/s (Before not with 30 mm/s) :

Retraction test with InnoFil

 

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I'm starting to think there are several causes to underextrusion that can be "erratic":

1) Filament tangling, filamant tight diameter coming off reel. Because the feeder is so much lower on the back of the UM2, the angle that the filament enters the feeder is at a strong angle. Especially when you are getting low on PLA.

2) bent filament. I found that a typical bended filament as it comes off the spool has trouble going through the white teflon part in the print head. If the filament is straight, it is so loose you can spin the teflon part around the filament but get a 10" diameter bend and it takes quite a bit of force (maybe 1 or 2 kg) to get through this part alone.

 

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Would be nice to have a mildly heated tube between the spool and feeder... probably not impossible to put together. But what new problems would it introduce? You'd have to make sure the filament was cool enough not to to get squashed by the feeder.

 

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He there.... does anybody remember my complains about underextrusion and bad printing? I did not checked the forum for a while. maybe a solutions might was posted last month... (changing the extruder design does not work/help)

I ordered a new nozzle, after it was available in the Ultimaker shop... I changed it (and the cold end and the tube, but they looked

Ultimaker2 Test Okt14 New Nozzle

not so bad)... now my U2 prints in speeds I NEVER got before. 0,3mm Layer at 70mm/s is no problem anymore. AND I can run it at 230 degrees!! (before, see ald pictures, I hat problems to get 50mm/s with 250 degress with a 0,2mm Layer!) And I had several discussions with the Ulti Support, too. I think there are only 2 explains for:

1st: a not well installed heat element /temp. sensor

2nd. a bad nozzle

or both issues in some ways combined...

So Ultimaker support... sometimes you can trust your customers if they tell you: there is something wrong with the nozzle! Have a good Night :)

Ultimaker2 Test Okt14 New Nozzle

 

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