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Stringing Towers Battle for the War on Stringing  

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Bryan De La Cruz
(@bryan-de-la-cruz)
Active Member
Stringing Towers Battle for the War on Stringing

Hello! I have had my Prusa Mini now, for about 3-4 years and never had an issue. Recently found out I could update firmware to 5.1.2. I did so and somehow lost all my custom print settings. I deferred to the default print settings and attempted a stringing tower, and have had many fails. S.o.S. Please Help! Thanks in advance!

Printing on stock Prusa Mini (no super pinda).

  • Filament: Esun PLA+
  • Nozzle temp: First Layer 205/ Other Layers 200
  • Bed Temp: First Layer 60/ Other Layers 60
  • Using .4 Nozzle
  • Using .15mm Quality preset with some custom settings.
  • The following are the custom settings I set.

Things I've done:

  • Squared the printer (x,y,z axis)
  • Rebuilt Extruder
  • Recalibrated/Reset Idler Arm
  • Checked Tension on x/y axis belts

Most Recent Stringing Tower has very wispy stringing, but now wont hold cylindrical shape. I'm shooting for high quality prints, dont care to much about speed.

Best Answer by fuchsr:

Not sure how upgrading firmware would lose any settings in your slicer 🤔 Hopefully you have backups of your computer so you can recover the configuration folder. If not, I'd try to go to the config folder (from the Help menu in Prusaslicer) and look for snapshots you can recover. 

From that screenshot I can't tell what settings you've changed. You'd be better off uploading a 3mf project file so we can see all the settings. 

If the posts of that stringing model don't hold their shape, you may want to check Filament Settings>Cooling>Cooling Thresholds>Slow down if layer print time is below and set that to a 1 sec or so.

Posted : 01/02/2024 12:17 am
Diem
 Diem
(@diem)
Illustrious Member

Unfortunately your picture is a little too fuzzy to see the fuzz in detail ...

How are you drying your filament?

Cheerio,

Posted : 01/02/2024 3:21 pm
fuchsr
(@fuchsr)
Famed Member
RE: Stringing Towers Battle for the War on Stringing

Not sure how upgrading firmware would lose any settings in your slicer 🤔 Hopefully you have backups of your computer so you can recover the configuration folder. If not, I'd try to go to the config folder (from the Help menu in Prusaslicer) and look for snapshots you can recover. 

From that screenshot I can't tell what settings you've changed. You'd be better off uploading a 3mf project file so we can see all the settings. 

If the posts of that stringing model don't hold their shape, you may want to check Filament Settings>Cooling>Cooling Thresholds>Slow down if layer print time is below and set that to a 1 sec or so.

Posted : 01/02/2024 6:09 pm
Bryan De La Cruz
(@bryan-de-la-cruz)
Active Member
Topic starter answered:
RE: Stringing Towers Battle for the War on Stringing

oof... actually i don't have a filament dryer. To clarify, there is no fuzz, its got wispy stringing, and the shape of the tower looks less cylindrical, and more like the dollops from a Dairy Queen ice cream cone. XD I hope that helps.

Posted : 01/02/2024 11:41 pm
Bryan De La Cruz
(@bryan-de-la-cruz)
Active Member
Topic starter answered:
RE: Stringing Towers Battle for the War on Stringing

 

Here is a better picture. Sorry about that!

Posted : 01/02/2024 11:59 pm
Bryan De La Cruz
(@bryan-de-la-cruz)
Active Member
Topic starter answered:
RE: Stringing Towers Battle for the War on Stringing

I don't know, I upgraded PrusaSlicer and Flashed the printer with new Firmware and lost any saved settings. I didnt make any back ups of settings because I didnt think it would replace them. Also, I tried to upload the 3MF file, but it says I don't have permission?

I'll fiddle around with the cooling threshold settings and see if it fixes things

 

Posted : 02/02/2024 12:05 am
Bryan De La Cruz
(@bryan-de-la-cruz)
Active Member
Topic starter answered:
RE: Stringing Towers Battle for the War on Stringing

OOh! Just adjusted the cooling setting:
Changed:

  • Full Fan Speed at layer: 4 to 0
  • Slow down if layer print time is below: 15 seconds to 0 seconds.

follow up question, is it kosher to run the fan on 100% of the time its printing? except... the first layer for the sake of adhesion

 

Update image of the print after making the changes, it seems to start wanting to retain the cylindical shape its meant to have. The woopy belly waves have reduced! Now to deal with... the little notch of underextrusion/veiny textur at the 10th-20th ish layer....

Posted : 02/02/2024 12:42 am
Diem
 Diem
(@diem)
Illustrious Member

I tried to upload the 3MF file, but it says I don't have permission?

Are you very new here?  IIrc the forum won't let you upload until after a certain number (10?) of posts.

You need to dry that filament.  I expect it to fix the stringing.

The irregular layer positions *might* be due to the drive pulleys slipping on the X&Y motors.  Or it may be due to belt tensions drifting out of spec.  Check the belt tensions first.

Print this: https://www.prusaprinters.org/prints/46639-tension-meter-for-the-gt2-belts-of-i3-mk3s-or-prus

It MUST be printed in Prusament PETG or the spring tension will be wrong.

Let us know how you get on.

Cheerio,

Posted : 02/02/2024 11:30 pm
Bryan De La Cruz
(@bryan-de-la-cruz)
Active Member
Topic starter answered:
RE: Stringing Towers Battle for the War on Stringing

Yesss.. I'm fairly new to the community. I've ordered a dryer which should be here in a few days. 
Stringing was reduced significantly with the cooling advice i received earlier.

I checked the Tension and im a little on the tighter side, but made some adjustments to sit as close to the middle of the guage.

I printed a calibration cube and it came out near perfect.

However, I tried printing a regular model and found some zebra stripes/wavy/veins on surfaces with 1mm thickness. Which seems to correlate with the wavy cylinders of the stringing tower. No sure what's causing this. 

Posted : 04/02/2024 5:08 pm
_KaszpiR_
(@_kaszpir_)
Honorable Member
RE: Stringing Towers Battle for the War on Stringing

can you give a photo how the object is placed on the print bed (screenshot from prusa slicer after slicing)?

See my GitHub and printables.com for some 3d stuff that you may like.

Posted : 05/02/2024 10:25 am
Bryan De La Cruz
(@bryan-de-la-cruz)
Active Member
Topic starter answered:
RE: Stringing Towers Battle for the War on Stringing

Here it is on the bed!

 

Posted : 05/02/2024 11:54 pm
Diem
 Diem
(@diem)
Illustrious Member
RE: Stringing Towers Battle for the War on Stringing

How thick are the walls showing the worst patterns?

Cheerio,

Posted : 06/02/2024 6:52 am
Bryan De La Cruz
(@bryan-de-la-cruz)
Active Member
Topic starter answered:
RE: Stringing Towers Battle for the War on Stringing

1mm

Posted : 06/02/2024 10:51 am
Diem
 Diem
(@diem)
Illustrious Member

1mm is too thin for good results.  With a standard 0.4mm nozzle extruding at the default 0.45mm width there is room for two perimeters and no interior, it is normal to have problems with such a narrow wall.  As  rule of thumb don't expect good walls with fewer than two external perimeters on each side and one inner extrusion to take up variation; around 2.5mm or more.

Cheerio,

Posted : 07/02/2024 4:05 am
Bryan De La Cruz
(@bryan-de-la-cruz)
Active Member
Topic starter answered:
RE: Stringing Towers Battle for the War on Stringing

Right on. Thank you for the advice! I've checked my file and found exactly what you described. .45mm extrusion width for 2 external perimeters on the areas with 1mm walls.

Posted : 08/02/2024 4:53 pm
Bryan De La Cruz
(@bryan-de-la-cruz)
Active Member
Topic starter answered:
RE: Stringing Towers Battle for the War on Stringing

Update: Rebuilt the extruder and found that I had a cracked idler spring! 

I made the following changes.

  • changed every moving print speed to 30mm.
  • Greased the x/y rods
  • Added a z brace to the frame from (Printables)
  • Rebuilt Extruder
  • Used a Coil jig to create a new idler spring with 3mm ID from 22GA Kanthal wire.
  • Increased nozzle temp from 205 to 215
  • Increased bed temp from 60 to 65

I printed a new model and discovered I had some underextrusion (zebra striping ish effect) during the retraction "phase". BUT on the whole model ZERO Stringing!

 

Which leads me to potentially my last question, whats a good DEtraction speed/length to counter my retraction? or should I just use the same speed/length as retraction?

Posted : 08/02/2024 5:07 pm
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