Cannot get rid of stringing

[taras 0]

Hi

Could you please give me your best advices for removing stringing?

I've followed the troubleshooting guide, hence tried different lower temperatures (all the way down to 180) at different lower speeds.

I've tried various combinations of retraction speed and retraction length, multiple filaments, but I just haven't been able to get a print without stringing from each retraction point to the next starting point.

Printing PLA on a UM2

Edited:

I get a combination of dots somewhere and lines elsewhere.

Thanks!

Kind regards Taras

 

[Dim3nsioneer 558]

Did you run into underextrusion when lowering temperature? If not, try going further down. If you can go down further, then something is wrong with the temperature sensor.

Some filament has a tremendous tendency for stringing. Are you printing with pure PLA or with a PLA/PHA mixture?

 

[taras 0]

Hi Dim3nsioneer

Around 180 I'm close to underextrusion, especially if I do not lower the speed accordingly, but I'l try to push the limit.

I've currently only printed with Ultimaker PLA, assuming it is pure PLA.

Thanks!

 

[taras 0]

Was wondering if bed level is just a tiny tiny twist to high... tried lowering it, but did it to much, so I started getting gaps in my lines.

Could bed level have influence on stringing?

Thanks!

 

[DidierKlein 729]

One thing that can limit stringing is increasing the travel speed, i tried 200mm/s and got good results, you can go up to 250mm/s (haven't tested that fast).

 

[Dim3nsioneer 558]

Another thought just crossed my mind: Make sure the nozzle is clean on the outside. If it gets covered by PLA, this has a adhesive effect onto further PLA and you get much more stringing. Maybe you have the situation that at some places material is not cooled down enough before the next layer is applied. This then leads to diving of the nozzle into the still soft PLA and getting covered.

 

[taras 0]

Didier > I'll try to increase travel speed to se if it "breaks" of the filement at retraction.

Dim3nsioneer > Hmm yes it is a bit 'dirty' from some of the ABS test I did. I'll try to clean it off.

Thanks - the both of you!

 

[gr5 2,265]

1) Are you certain retraction is happening at all? There are 6 or so settings that control it. You can verify it in layer view.

2) Please post a picture because what you call stringing we might call something totally different like "bad Z axis" or underextrusion.

3) Consider increasing retraction distance. When my UM2 was new 5.5mm was perfect. Now that I have the bowden tube locked tight in the print head and it never moves up and down anymore I can do 4.5mm and that's perfect.

4) Some brands of PLA do a small amount of thin stringing no matter what you do.

5) Printing very slow (e.g. 20mm/sec) greatly reduces pressure in print head and reduces stringing to pretty much zero. But you shouldn't have to go this low. I recommend printing some kind of stringing test part like the first photo here:

http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/

Then modify settings like retraction distance, and print speed WHILE it is printing.

 

[taras 0]

Hi Guys

Sorry for not replying, I've been down with the flue.

gr5 >

1)

Retraction is ticked in Cura, and the layer view shows retraction lines.

2)

I've attached a pic. of the 'stringing'-lines. They are equivalent to the retraction lines in Cura's layer view.

They continue throughout the entire print, and are visible from the bottom layer to the top.

http://www.bredel.dk/um2/IMG_2829.jpg

3)

I have tried different retraction setting, currently running 6 mm and 30 mm/s

4)

I have tried different filaments, though all from UM and PLA

5)

I've set printing speed to 25 mm/s and travel speed to 200 mm/s

While printing, I then try to set speed to 50%, but it does not do the trick.

Temperature is around 190

Guess i'll have to try the stringing test to se if I can sort it out.

 

[taras 0]

And a picture a little further into the print...

http://www.bredel.dk/um2/img_2831.jpg

gr5 edit: fixed link

[DidierKlein 729]

That's not stringing, look at these links:

http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#scratches

http://support.3dverkstan.se/article/30-getting-better-prints#retraction-and-combing

 

[taras 0]

So not stringing, scratching :-)

...phew there are many phenomenons and corresponding tweeks to learn.

I seem to experience many attempts where I adjust settings to avoid something and then introduce something else, or even worse, try to avoid something which appearently is me having the wrong perception of what the problem is, hence I end up wondering why none of my variations in setting makes a difference.

I love my UM2, especially when it is aided by so much expertise and guidance... one day, one day, that is me giving answers to folks!

Thanks all!