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New Prusa MINI with really bad stringing.  

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LayerLux3D
(@layerlux3d)
New Member
New Prusa MINI with really bad stringing.

Hi,

I just bought the MINI kit and I really struggle with stringing from the start with this printer.

I use default settings in the Prusa slicer for the MINI and have stringing issues with the original Prusament that was provided as a sample in the kit and with other filaments as well.

The stringing is also with the original files from the USB drive. The Benchy turned out good so far, but also with stringing. 

That must be some mechanical issue, but I can't figure out what...

Thanks!

 

Posted : 11/11/2022 11:47 pm
Thomas Lynch
(@thomas-lynch)
Estimable Member
RE: New Prusa MINI with really bad stringing.

Looks like classic wet filament. If you have not been storing your filament in a dry box with low humidity you will get stringing.

Posted : 12/11/2022 1:44 am
Diem
 Diem
(@diem)
Illustrious Member

I agree with @thomas-lynch, look up threads here about drying filament.

Cheerio,

Posted : 12/11/2022 1:53 am
LayerLux3D
(@layerlux3d)
New Member
Topic starter answered:
RE: New Prusa MINI with really bad stringing.

I don't think that it is wet filament. 

The blue and black prints are with the sample Prusament filament right out of the seal. (The printer is new and just arrived a week ago. So the filament is new as well.)

I tried other filament for a test with my Ender 3 V2 (40 days of print time in total with an old nozzle and without upgrades).

The red generic filament is about 3 years open and was always on the air, and the silver generic filament is about 1 year open.

On the left side is the Ender3 result and on the right side the Prusa MINI. Again, the MINI print is sliced with default settings for PLA. Both are 215C.

Posted : 12/11/2022 7:53 am
karl-herbert
(@karl-herbert)
Illustrious Member
RE:

If there is a mechanical problem, I would look at the Bowden PTFE (loose fittings), too much backlash in the extruder drive, insufficient retraction, or low fan power.

I would also try to reduce the nozzle temperature in 5 degree increments and fan power 100 percent.

wbr,

Karl

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.

Posted : 12/11/2022 1:24 pm
Diem
 Diem
(@diem)
Illustrious Member

Dry the filament first then come back here if problems remain.

Filament can get damp enough for print degredation within a few hours.  Sometimes the beginning of a print may be fine but in some atmospheric conditions the end stages can be badly affected.

Cheerio,

Posted : 12/11/2022 2:27 pm
René
(@rene-3)
Reputable Member
RE:

Also recently got a mini+ kit and love this small printer.
Haven't had these problems yet. Not with Prusament and generic filament (PLA).

Hopefully this page can help you further,

https://help.prusa3d.com/article/stringing-and-oozing_1805

Posted : 12/11/2022 3:11 pm
René
(@rene-3)
Reputable Member
RE:

Here's a image of my flute object from the Prusa stick (gcode)

 

 

(@Prusa, the time you can edit a message is very short, can you please extend that time? Thank you.)

Posted : 12/11/2022 3:28 pm
LayerLux3D
(@layerlux3d)
New Member
Topic starter answered:
RE: New Prusa MINI with really bad stringing.

I checked out the page. But it basically says that I should use default settings. That is what I did. Default settings with the Prusament and bad results. 

I now opened up a new sealed filament and printed it immediately on the Prusa first.

Right is 215C, Middle is 190C and the left one is on the Ender3 with almost zero stringing (it separated a bit from the bed that's why it is so jenky). I think we can rule out wet filament here. 

@Rene that is how I would expect my flute to be as well. 🙁

The bowden PTFE tube look good and is tight.

I guess my next step is to take apart the hotend and extruder...

Posted : 12/11/2022 4:00 pm
mark
 mark
(@mark-3)
Reputable Member
RE: New Prusa MINI with really bad stringing.

The mini seems more sensitive to wet filament than others. I can confirm after printing 16 hours a day for months straight with the Mini that drying the filament always helps. I might suggest if you haven't already to update to the latest available Prusa Slicer and the latest Beta firmware. They keep improving both. The latest Arachne perimeter generator and the Pressure Equalizer have improved print quality. You have to slice using the latest one. Reusing gcode from what comes on the USB stick won't give you these improvements.

Regards,

Mark

Posted : 12/11/2022 4:38 pm
dan2304k
(@dan2304k)
New Member
RE: New Prusa MINI with really bad stringing.

It's somehow "in vogue" to blame everything on wet filament.  Ignore them.  Clearly you have ruled this out multiple times already.

Your prints from the sample g-code show multiple signs of extrusion issues -- it's not just stringing, there are other problems too.

Check that the grub screws are tight on your extruder gear.  Check that there's no filament ("chewed filament") stuck to the gear.  Remove the PTFE tube and make sure filament passes freely through it and it's not kinked or over-compressed by the olive nuts.  Perform a cold pull and make sure your nozzle isn't partially clogged.  Lastly, check the small PTFE tube inside the heat sink and verify the length is to spec.  There are other possibilities as well.  Just work through things one at a time and you'll find the issue.

Also consider contacting Prusa support.  A new machine, shouldn't have these issues.

Posted : 20/11/2022 2:00 am
Erik, Tysonsw, and 1 people liked
Diem
 Diem
(@diem)
Illustrious Member
RE:

You have wet filament.  It is very common at this time of year and will be again in four or five months as the seasons change and heating/air con is switched on or off.

You have not ruled it out.  If you got your Ender dialled in correctly you would see stringing there too.

New filament is not necessarily dry filament.

The cheapest, easiest, least consequential fix you can try is to DRY YOUR FILAMENT.

So: Dry the filament first then come back here if problems remain.

Cheerio,

Posted : 20/11/2022 3:28 am
LayerLux3D
(@layerlux3d)
New Member
Topic starter answered:
RE: New Prusa MINI with really bad stringing.

I did some more reprints with different filaments.

I don't have a dryer and I don't want to buy one just because one of my machines can't print PLA without stringing like crazy. And I don't want to dry my filament in my family oven, where I will make pizza the next day.

I'm printing PLA here. If it were nylon, then we can talk about wet filament. But I tried different brands, different ages and filament right out of the seal!

If my printer considers every PLA I throw at i "that is too wet for me", then sorry, but that is not why I bought a PRUSA.

I talked to other people with the MINI, and they NEVER had any issue with stringing like that. I'm not storing my filament in the garden, but in my office. It is warm and dry.

>  If you got your Ender dialled in correctly you would see stringing there too.

Sorry, I don't understand that. My Ender is dialed in wrong and therefor it prints good? If I dial it in right, it will print sh**ti as well?

I have ordered a BondTech extruder. Let's see what the result is then. I will update you guys how the result is after that.

Meanwhile, I have two more pics. With the green filament, I dialed down the temp by 5 degree. From left to right 215, 210, 205, ...

The other two prints (gray and red) are 215 and 190 degree. Whereas the 190 version has less stringing but than issues with bed adhesion.

Before I take apart the extruder, I'll try the BondTech first.

Posted : 20/11/2022 11:34 am
Erik liked
Feberer
(@feberer)
Member
RE:

Did the Bondtech solve the issue? I have also Prusa Mini (amongst lot of other Prusa family printers) and I have exactly same issue, stringing like hell, different filaments, different retraction settings, endless extruder and hotend remounting and tweaking, no luck. This problem came suddenly, it works like a charm and then something happens, can't tell what (I changed lm8uu's to teflon tubes and changed nozzles few times) but this issue seems persistent. Possible heat creep in hotend? 

This post was modified 9 months ago by Feberer
Posted : 18/05/2023 6:35 am
Tysonsw
(@tysonsw)
Trusted Member
RE: New Prusa MINI with really bad stringing.

 

Posted by: @feberer

Did the Bondtech solve the issue? I have also Prusa Mini (amongst lot of other Prusa family printers) and I have exactly same issue, stringing like hell, different filaments, different retraction settings, endless extruder and hotend remounting and tweaking, no luck. This problem came suddenly, it works like a charm and then something happens, can't tell what (I changed lm8uu's to teflon tubes and changed nozzles few times) but this issue seems persistent. Possible heat creep in hotend? 

Do you have the latest slicer and and firmware version? Does it matter which filament that you use?

 

Printer: Original Prusa Mini+
Nozzles: E3D 0.25, E3D Nozzle X 0.4 , E3D 0.4, Bondtech 0.6 CHL
Printables: Tysonsw
Mastodon: [email protected]
.

Posted : 19/05/2023 7:39 am
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