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Mf1ve
(@mf1ve)
Active Member
RE:

Agree, I reduced the temperature for PETG down to 230°C and also pushed the print fan up to 100%. This made some difference, while other things I've tried (more retraction, etc.) did not affect the print. Even putting a c-clamp on the idler door to try more idler pressure made no difference (I let that run for a couple of hours, then removed it again and ran for another two hours, and I couldn't find a difference in the print - interesting experiment).  

Posted by: @investegate

Yea got the same issues with stringing and oozing on my multitool XL... More Retraction doesnt help. only to reduce temperature helps a little bit. 

 

 

 

 

This post was modified 8 months ago by Mf1ve
Posted : 10/09/2023 4:56 pm
Holck
(@holck)
Eminent Member
RE: Stringing Issues

Have the 5 toolhead version - I’m also seeing massive stringing with petg. Much more than from the mk3 and mk4 extruders.

it seems to stem from massive oozing of filament from the nozzle as soon as a toolhead is picked up.

I was surprised when I first loaded up the 5 toolheads. After I pushed the filament to reach the toolhead filament sensor, it took a really long extrusion time until filament started running, but then it almost didn’t stop again until the toolhead was docked again. Could be retraction related or inadequate back pressure.

havent had time to investigate further

Posted : 13/09/2023 9:43 pm
Holck
(@holck)
Eminent Member
RE:

here is a test I did after assembly:

- on top: PLA test print as supplied on the printer bed.

- on bottom: PETG print (Prusament) sliced in prusaslicer with Prusament PETG preset. 5 colors in 5 toolheads. Massive stringing, under extrusion, and very uneven surface finish

 

This post was modified 7 months ago 3 times by Holck
Posted : 13/09/2023 10:25 pm
MME
 MME
(@mme)
Reputable Member
RE: Stringing Issues

Has anyone tried a scrubber in front of the docking station?

Posted : 13/09/2023 10:54 pm
DarkTeck
(@darkteck)
Trusted Member
RE: Stringing Issues

Such a dang shame this is a such a HUGE potential with this machine . I’m firmly believing it’s a firmware / slicer issue that hasn’t been worked out and all the multi tool machines shipped are still in like a beta format . I’m willing to bet after a few updates and firmware updates it’s gonna resolved becuase you aren’t seeing these issues on the single to 

Posted : 14/09/2023 3:38 am
INVESTEGATE
(@investegate)
Eminent Member
RE: Stringing Issues

 

Posted by: @mme

Has anyone tried a scrubber in front of the docking station?

Not yet. But i will do this in the near future. I was also surprised why no one has done this with a good brush and a suitable user-defined gcode

Posted : 14/09/2023 12:02 pm
nRegistered
(@nregistered)
Member
RE: Stringing Issues

Hi All,

I have two extruder model that was assembled by Prusa.  I am having stringing issues as well as everyone else.  I've been wondering if part of the problem is the way the extruder block is angled towards the part cooling fan.  The multi tool assembly manual images show the extruder block angled toward the fan shroud. When I have the silicon sock on it is blocking a lot of direct air from hitting the part which would potentially allow for stringing.  If you look at the assembly images for the mk4, the nozzle block is more parallel to the fan instead of being angled towards it. It seems like the mk4 gets better part cooling. Not sure if that makes sense or not.

Posted : 17/09/2023 6:04 am
3dprintingrookie
(@3dprintingrookie)
Trusted Member
RE: Stringing Issues

Soooo anyone figured out a solution for this?

Posted : 18/09/2023 3:50 pm
jsawyer
(@jsawyer)
Active Member
Topic starter answered:
RE: Stringing Issues

Not so far. I am running a couple of tests today to see if the silicone socks are impeding the part cooling air flow but that is not looking like it is the issue.

Posted : 18/09/2023 7:46 pm
3dprintingrookie
(@3dprintingrookie)
Trusted Member
RE: Stringing Issues

FWIW I am not using the socks (basically have no idea how to install them without moving the nozzle block), still have stringing without them

Posted : 18/09/2023 7:52 pm
jF
 jF
(@jf-2)
Trusted Member
RE: Stringing Issues

 

Posted by: @nregistered

[...] If you look at the assembly images for the mk4, the nozzle block is more parallel to the fan instead of being angled towards it. It seems like the mk4 gets better part cooling. Not sure if that makes sense or not. 

Looking at the actual 3d model for the mk4 there is a huge difference between both. The mk4 has a proper shroud directed at the nozzle while the XL basically just has a slot pushing air in the general vicinity of the nozzle. It's not even close to lining up with the nozzle too. Such a weird design choice.

Can wait for a community-made redesign of that part.

Posted : 19/09/2023 8:54 pm
nRegistered
(@nregistered)
Member
RE: Stringing Issues

I have to image the weird nozzle placement with regards to the part fan contributes somewhat to the stringing. 

Posted : 19/09/2023 9:33 pm
xenon
(@xenon)
Trusted Member
RE: Stringing Issues

the fan rotates ccw, the air doesnt exit that slot at 90°.

maybe put a glass of water under it and watch the ripples

 

Posted : 20/09/2023 2:40 pm
INVESTEGATE
(@investegate)
Eminent Member
RE:

It seems like something has improved significantly.

The print quality has improved significantly since 2.6.1 and the current configuration. Especially with multi-material printing.

I print PLA from Eryone with 205c and 0.6mm Obxidian nozzle.

I also added the 3mf. file. So you can take a look at my config and also print it. Just click me!

It is very important that the nozzle seal is adjusted perfectly!

When pared, the nozzle should only press the seal down a little (1-2mm)

Here you can clearly see the difference! 

On the left, you see the new print with better adjusted nozzle seal and Prusa Slicer 2.6.1

On the right, you see the old messy print with Prusa Slicer 2.6

 

This post was modified 7 months ago 2 times by INVESTEGATE
Posted : 22/09/2023 1:06 pm
3Dmate.cz and Denjo liked
INVESTEGATE
(@investegate)
Eminent Member
RE:

Here you can see exactly how to set the nozzle seal:

This post was modified 7 months ago 2 times by INVESTEGATE
Posted : 22/09/2023 1:20 pm
Andreas
(@andreas)
Eminent Member
RE: Stringing Issues

I'm owning a semi-assembled double-toolhead XL, running 4.7.2 (seems to be the latest fw available). The print quality is poor, no matter what printhead I'm using.

Moving the same material (Prusament PETG) to one of my MK3S lead to perfect prints (no stringing, nothing, just perfect). But with the XL, prints look like this, no matter of big or small.

Poor bridging, poor print quality, and a lot of stringing...

 

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Posted : 26/09/2023 3:21 pm
3Dmate.cz liked
Twobit
(@twobit)
Member
RE: Stringing Issues

I guess I opened a new topic for this same thing. I have the same results.  the blobbing is happening when the head moves from nozzle purge tower to the print, A blob is hanging and catches the print. makes for weird little blobs all up the seam of the print. I've played with settings but adding z-lift gets rid of the blobs but makes it very stringy. 

so not all xl's are like this? My results are nearly identical to the above pictures too.

Posted : 27/09/2023 2:21 am
3Dmate.cz liked
jsawyer
(@jsawyer)
Active Member
Topic starter answered:
RE: Stringing Issues

Ok, I have managed to get prints with almost no stringing.

I had to drop the temps WAY down. I am printing PLA at 195 and PETG at 205. 

I am tempted to pick up a good thermocouple to test if that is the actual temp or if there is a calibration issue with the thermistor.

Posted : 27/09/2023 11:43 pm
Mf1ve
(@mf1ve)
Active Member
RE: Stringing Issues

I will try this too. I had already dropped my PETG temp down, but not that much. And, you know, I do have thermocouples. I'll investigate the temperature as well.

Posted : 27/09/2023 11:52 pm
Mf1ve
(@mf1ve)
Active Member
RE:

I did the following to check the nozzle temperature:

  • I drilled a shallow hole in the heat block on the side face, between the RTD and the nozzle.
  • I added a 0.5mm thermocouple (bare wire with bead) in the drilled hole
  • I installed the silicone sock to hold the thermocouple in place and to reduce heat loss through the thermocouple wires to the air

Here are the results: 

Prusa temp 200°C -> thermocouple temp 203°C

Prusa temp 240°C -> thermocouple temp 243°C

Prusa temp 280°C -> thermocouple temp 284°C

So, according to these readings, the Prusa nozzle temperature calibration is good. I would not be surprised if my thermocouple reader and/or thermocouple are a few degrees off, and it is the Prusa that is closer to the real temperature, in fact. I didn't calibrate the Omega thermocouple reader, or the thermocouple. 

 
Posted by: @jsawyer

Ok, I have managed to get prints with almost no stringing.

I had to drop the temps WAY down. I am printing PLA at 195 and PETG at 205. 

I am tempted to pick up a good thermocouple to test if that is the actual temp or if there is a calibration issue with the thermistor.

 

This post was modified 7 months ago by Mf1ve
Posted : 28/09/2023 2:27 am
Denjo and INVESTEGATE liked
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