Stringing: I am about to throw away the printer...
 

Stringing: I am about to throw away the printer...  

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staicontento
(@staicontento)
Active Member

Dear all,

again here to ask for your precious help.

I've already successfully printed with 0.2 mm. Now I changed the nozzle to a 0.4 mm one., but I'm getting an absurd stringing!

What I tried until now, without success:

  1. Lower temperature (various levels);
  2. lower speed;
  3. lower flow (various levels);
  4. filament change (different brands);
  5. ensured that the nozzle is tightened to the heat break (and not with the heat block);
  6. different extrusion width (from 0.40 to 0.60);
  7. two different 0.4 nozzles (same brand though).

Now I am totally stuck... Totally don't know what to do more... Any help?

Many thanks.

Posted : 29/11/2019 11:51 am
staicontento
(@staicontento)
Active Member

I forgot to point out that I also changed the heat block with a new one, still aluminium (but not Prusa's) having a slightly different geometry. Can be it?

Posted : 30/11/2019 6:00 pm
joan.t
(@joantabb)
Veteran Member Moderator

a new heatblock, may adjust the relative positions of the nozzle and the filament cooling fan, and undermine the PID settings!

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 01/12/2019 12:11 am
alexander.s27
(@alexander-s27)
Estimable Member

Thats a big list what have you all done. What I am missing is something about retract settings extra restart lenght and M900 linear advance...

Posted : 01/12/2019 7:16 am
staicontento
(@staicontento)
Active Member

@alexander-s27

I tried different retraction lengths, from 0 to more than 2 mm, it did not affect the final result. Sorry I don't know what M900 is...

Posted : 01/12/2019 9:43 am
staicontento
(@staicontento)
Active Member

@joantabb

Thanks, I will try to redo the PID tuning and post the results here.

Posted : 01/12/2019 9:44 am
joan.t
(@joantabb)
Veteran Member Moderator

Linear Advance varies per material and also per printer type.

in the picture above you can see that

Generic Flex has linear advance turned off (M900 K0) where as 
Generic PLA has two values for Linear advance, depending upon whether the Printer is Direct Drive extruder (Mk1, Mk2, Mk3, Mk3 with MMU2) or Bowden drive Extruder (Mk2 with MMU1 and probably Mini)

each material can have a different K value, and different extruder configurtions can require different K values... 

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 01/12/2019 11:01 am
staicontento
(@staicontento)
Active Member

@joantabb

Hello, I checked and I was printing with M900 K30, since my nozzle is 0.4mm. How can understand if this number is correct?

I also tried to replace the heat break with one in titanium. Tried as above with different settings, still same bad situation: 

And, in the meantime I ordered new heatblock and nozzles...

Posted : 03/12/2019 11:22 am
Lichtjaeger
(@lichtjaeger)
Prominent Member

Did you try to dry your filament?

This post was modified 8 months ago by Lichtjaeger
Posted : 03/12/2019 11:49 am
staicontento
(@staicontento)
Active Member

@lichtjaeger

Hello! Yes, I tried to dry it and also I bought a couple of new filaments, freshly opened, same result. At this point I will try to:

  • change the heat break with a more expensive one...
  • change the nozzle with a more expensive one...
  • change the thermristor

P.S. I re-ran PID calibration, temperature calibration after every modification... Still no changes. It's driving me crazy!

Posted : 03/12/2019 11:57 am
staicontento
(@staicontento)
Active Member

UPDATE: I replaced the heat break with a titanium one and tried with the original Prusa 0.6 nozzle, same results.

Tomorrow I'm gonna try to change thermistor (same 100 KOhm of another brand) and the heat block too.

Posted : 05/12/2019 10:25 am
bobstro
(@bobstro)
Illustrious Member
Posted by: @staicontento

I forgot to point out that I also changed the heat block with a new one, still aluminium (but not Prusa's) having a slightly different geometry. Can be it?

What exactly is different? Were other components switched as well? You seem intent on using clone parts which is going to make troubleshooting more difficult. Obvious suggestion is to try an E3D hotend which the printer is designed for. 

This post was modified 8 months ago by bobstro
My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 05/12/2019 11:48 am
Lichtjaeger
(@lichtjaeger)
Prominent Member

You know, there are two retraction settings in PS.

There is one in the printer settings and there are overwrites in the filament settings. Maybe your retraction adjustments don't show any effect because they got overwritten by the filament setting.

Posted : 05/12/2019 12:04 pm
staicontento
(@staicontento)
Active Member

@lichtjaeger

In Filament Settings / Filament Overrides everything is unchecked, so I guess it is not the problem. Thanks anyway.

Posted : 05/12/2019 6:12 pm
staicontento
(@staicontento)
Active Member
Posted by: @bobstro
Posted by: @staicontento

I forgot to point out that I also changed the heat block with a new one, still aluminium (but not Prusa's) having a slightly different geometry. Can be it?

What exactly is different? Were other components switched as well? You seem intent on using clone parts which is going to make troubleshooting more difficult. Obvious suggestion is to try an E3D hotend which the printer is designed for. 

At the moment only two things are not original:
- heat block
- thermistor

I went back to the original 0.6 mm Prusa nozzle. Same stringing.

I am waiting for a new TCMUK-3D heat block (a v6 clone), even if I do not think that the heat block can affect stringing so much, and also for a new thermistor.
Thanks to everyone for the help, I will keep you posted.

Posted : 05/12/2019 6:17 pm
ferdinand.b3
(@ferdinand-b3)
Active Member

I've had this problem in the past, and I successfully managed to get rid of it after reading some articles about stringing:

https://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#pillowing (scroll down to stringing)

https://ultimaker.com/en/resources/19504-how-to-fix-stringing

https://www.simplify3d.com/support/print-quality-troubleshooting/stringing-or-oozing/

Hope this will help.

Ferdinand.

 

...
Posted : 07/12/2019 2:47 am
staicontento
(@staicontento)
Active Member

Hi everyone! As an update:

1) changed the thermistor with a new one (FYSETC)

2) changed the heat block with a new one, v6 new style (TCMUK-3D)

I re-ran all the calibrations (XYZ, PID, first layer...). Incredibly I have seen no effect on the final product:

Given this,  I am starting to think of some trouble on the control system. What do you think?

How can it be possible???

@Ferdinand, I appreciate your links but every time I am trying at different temperatures and with different retraction settings. This is not a common stringing problem, as I've been printing with different settings for 2 years.

Posted : 07/12/2019 10:52 am
bobstro
(@bobstro)
Illustrious Member

I'd definitely try a Prusa or E3D thermistor.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 07/12/2019 3:19 pm
staicontento
(@staicontento)
Active Member

I am gonna give this a conclusion:
(Too) many factors are involved in stringing. Apart from the common ones (retraction, temperature, bad filament) there are many others... and I found another two.

1) After changing thermistor I had run PID calibration many times but the results were really bad (see above). Then I followed an advice I read somewhere: run PID calibration keeping the fan on. This was the real breakthrough!

2) The stringing test I was using was too demanding: it had a variable column section, quickly becoming too small for the nozzle that couldn't be wiped enough when going from left to right. Smaller the column section area, more the stringing (as you can see in the previous pictures). Then I switched to a constant column section.

Results
I did the following test using 0.8 mm retraction at 190° (the rest is all standard Prusa settings). The left one is without z-lift, the right one with 0.6 z-lift:

It is not like the old days but still a good result.

Thank you for your support.

P.S. Sorry for the bad photos... I didn't take advantage of black friday... Still an old phone 😭 

Posted : 07/12/2019 6:03 pm
bobstro
(@bobstro)
Illustrious Member

If you calibrate your filament settings and use dry filament, you should be able to minimize stringing using the standard Prusa hardware. Here are my  results using Filastruder Veracity PETG starting with 0mm retraction and 0 z-lift at bottom left and working to the right and back increasing retraction 0.1mm for each position. 

This post was modified 8 months ago by bobstro
My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 07/12/2019 6:45 pm
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