Under extrusion or gaps at seams with latest versions of PrusaSlicer/firmware

[FutureSharks]

Description of the bug

Seams have gaps, holes or just look worse than before:

1. GOOD: Prusa Mini+ firmware 4.x+ Slicer 2.7.0x
2. NOT GOOD: Prusa Mini+ firmware 5.1+ Slicer 2.7.1, input shaper NOT enabled
3. BAD: Prusa Mini+ firmware 5.1+ Slicer 2.7.1, input shaper enabled

I can't tell if it's an issue with PrusaSlicer, my Prusa Mini+ firmware or the printer settings as all 3 of these were updated at once.

Here's some photos to show what I'm talking about, this is without any input shaper and compares old vs new versions:

And this compares input shaper vs no input shaper on new versions:

Project file & How to reproduce

The model is here if it helps but I don't think it's important, I see it in all prints.

Checklist of files included above

• Project file
• Screenshot

Version of PrusaSlicer

2.7.1

Operating system

Mac

Printer model

Prusa Mini+

[go4blossi]

Hey, i have the same problem after i updated my printer and try to use input shape

[vazmuten]

I have same issue using Prusa Mini+ (FW 5.1.2) and PrusaSlicer 2.7.1. I think this is a HUGE problem that should be fixed ASAP.

[FutureSharks]

Could someone test with an older version of PrusaSlicer to rule out the firmware?

[vazmuten]

Here are some results showing that FW 5.1.2 using Input Shaping causes the problem:

[arthurptj]

having same issue

[jeloneal]

Same issue here. Underextrusion also on some surfaces after the swith to 5.x firmware.

[D3nkis]

Hi colleagues,

Same issue here.
The previuos 4.x firmware was perfectly, but after I've switched to the new one, the quality along the seams is unacceptable.

[dpvdberg]

Exactly the same issue here! Using input shaper (MINIIS) with 5.1.2 firmware and PrusaSlicer 2.7.1.

[tysonsw]

Same issue here.
Prusa MINI+ with firmware 5.1.2 and using PrusaSlicer 2.7.1.
Had almost no seams with the previous profiles.
The problem is present with both add:north PLA and PETG filament.

[neophyl]

Lynn on the thread about this on the Prusa forum has brought up a good point. Are those of you experiencing this issue using modified linear advance settings for your filament profiles ? As none of you have actually attached a saved PS project file to this issue its impossible to check that at the moment, hence the question.

I know from previous communication with tysonsw that the add:north filament profile he is using is not an IS profile but the standard one. Might be worth trying the adjusted values from a IS adjusted profile as a starting point if they arent there already to see if it makes a difference.

[FutureSharks]

As none of you have actually attached a saved PS project

I can attach a project file if it helps but I assume not since it seems for most people a problem for every project/model that uses the newer IS profiles.

Might be worth trying the adjusted values from a IS adjusted profile as a starting point

How does one do that?

[D3nkis]

Hi,

the problem still exist on the MK4 printers since the same firmware version 5.1.2 and the Prusa Slicer 2.7.1

prusa3d/Prusa-Firmware-Buddy#3651

[sirgrej]

After doing some tests with different MK4 FW versions I now thing this might be a slicer issue. I have tested fw 5.1.2, 5.0.1 and 4.7.2. The results look all the same independent from input shaping.

Maybe it is worth to try another slicer version or even another slicer to track the issue down

[Mikyner]

[D3nkis]

Is it printed with Input shaper speed profile in Orca?
Much better than PS.

[Mikyner]

Yes, Orca Slicer contains only IS profiles for MK4
0.2mm Standar @mk4

[D3nkis]

In afternoon I want to test the printing quality with Orca, I never used it before, I’ve choosed the Prusa Mini printer type, but I could’t find the IS profile and I gave up :D

Are you happy with this quality and will you switch from PrusaSlicer to Orca until Prusa doesn’t solve the problem?

[Mikyner]

Unfortunately Orca does not include an IS profile for Prusu mini.
For now, I have no choice but to use Orca slicer, because I can throw away a lot of prints (from expensive filament) due to a bug in PS.

In Orca I miss a structural profile like in PS, I guess I'll have to create one because it's not available for download anywhere.

Anyway, if print profiles for MK4 were available for Orca (for example structural), or could be easily transferred from PS, I might stick with Orca, it has a lot of tweaks I like.

[sirgrej]

I have tested prusaalicer 2.6.1 with mk4 and firmware 5.1.2 and the seam looks much better

The upper print is with 2.6.1 and the lower is with 2.7.1

[thenhustey]

For me it seems as general problem with under-extrusion on beginning (at least) perimeter.

The seam is under-extruded. And also this perimeter is under-extruded on its beginning.

I printed 2 copies of this part and both look exactly the same.

MINI+
FW: 5.1.2
PrusaSlicer 2.7.1 +win64
Nozzle: 06,mm
Material: PLA
Printer settings: 0,15mrn STRUCTURAL
Filament profile: Prusament PLA
Printer profile: Original Prusa MINI & MINI+ Input Shaper 0.6 nozzle

[mimeister]

I'm seeing these quality issues regarding the seam on my Mini+, too. However, the biggest issue came from the K-factor for linear advance being incorrect, because the input shaping printer profile identifies as a different printer model (PRINTER_MODEL_MINIIS instead of PRINTER_MODEL_MINI), but some (not all) filament profiles that I migrated check for Mini without IS:

M900 K{if printer_notes=~/.*PRINTER_MODEL_MINI.*/ and nozzle_diameter[0]==0.6}0.12{elsif printer_notes=~/.*PRINTER_MODEL_MINI.*/ and nozzle_diameter[0]==0.8}0.06{elsif printer_notes=~/.*PRINTER_MODEL_MINI.*/}0.2{elsif nozzle_diameter[0]==0.8}0.01{elsif nozzle_diameter[0]==0.6}0.04{else}0.05{endif} ; Filament gcode LA 1.5
{if printer_notes=~/.*PRINTER_MODEL_MINI.*/};{elsif printer_notes=~/.*PRINTER_HAS_BOWDEN.*/}M900 K200{elsif nozzle_diameter[0]==0.6}M900 K18{elsif nozzle_diameter[0]==0.8};{else}M900 K30{endif} ; Filament gcode LA 1.0

So the above code produces M900 K0.2 for my Mini without IS (correct value), but M900 K0.05 if the IS profile is used. Adding a simple or printer_notes=~/.*PRINTER_MODEL_MINIIS.*/ fixes that (or just remove the check for the printer model at all, if you don't need it), which seems to mitigate the worst underextrusion.
But still, seams don't look good as others have pointed out before.

Input Shaping with bad K

Really bad underextrusion at the seam. Somewhat expected because of the much too low K-factor.

Input Shaping with correct K

At least no big gaps, but still some underextrusion.

[carnas1]

Has anyone contacted support? if so, what was the conclusion?

[FutureSharks]

Has anyone contacted support? if so, what was the conclusion?

The PrusaSlicer page says this:

Found a bug? Let us know on Github or via community forum.

Both of which I have done 😅

[uncovery]

Same here, the seams are really terrible. My MK3 used to have much nicer seams.

[carnas1]

good day. the problem has been reported for a long time. Is there really no reaction from Pruša?

[uncovery]

ok, so I talked to Prusa support and they recommended to change the "External perimeters first" in the advanced settings of the "Layers and perimeters" section to ON. I asked why this is not on by default and was told that it might affect overhangs. Anyhow switching this on had a dramatic effect for the better. I also did seams on "REAR" instead of aligned and they came finally in a straight line. Seems I have to do 2 different presets for "nice" and "overhangs"?

[mix579]

Interesting. So if you have overhangs, you're still screwed...

[webbes]

Same issue on my Mini+ here. Huge gaps at the seams. Does not matter if I select the IS printer profile or not. I'ld never expected Prusa to deliver such a terrible slicer or firmware version. I'm on stock Prusa, using Prusament because I don't want to deal with quality issues. They used to just work. Attached picture is with latest firmware (5.1.2) and Prusa Slicer (2.7.1), non IS printer profile, Prusament PETG filament. Only change from default is 30% infill instead of 15% and a Diamondback 0.6 nozzle.

UPDATE
OK, the firmware causes a shortage of fillament at the start of any line (as if it retracts more than it detracts), the slicer software update changes the order in which the perimeters are being print. Using Prusa Slicer 2.6.1 the seams start on the inside, so you have the gaps on the inside. Still not good as it weakens the structure of the print, but at least it's not that ugly.

For now all I can do is go back to a previous firmware.

[SimonTratter123]

I asked the support today and he suggested to check the length of the Hotends PTFE tube. And mine was only 42mm instead of the 43.4mm on the prusa mini. After replacing it, my mini is printing again with no issues.
https://help.prusa3d.com/guide/how-to-replace-a-hotend-ptfe-tube-mini-mini_119449

[michal-repo]

I asked the support today and he suggested to check the length of the Hotends PTFE tube. And mine was only 42mm instead of the 43.4mm on the prusa mini. After replacing it, my mini is printing again with no issues. https://help.prusa3d.com/guide/how-to-replace-a-hotend-ptfe-tube-mini-mini_119449

so suddenly in all mini's PTFE tube shrank?

[gferon]

More examples of terrible seams with my MK4 (I've tried a bunch of suggestions in this thread, and nothing worked).

[khenderick]

It worked before without fiddling with the settings, so it should work again without fiddling with the settings. That's where the Prusa-provided profiles are for.

Awaiting a working profile I switched to Orca slicer. Does that option work better for you? For me it definately got rid of the massive gaps. And they also have scarf joints, so it's even better in some cases 👌.

[gferon]

Awaiting a working profile I switched to Orca slicer. Does that option work better for you? For me it definately got rid of the massive gaps. And they also have scarf joints, so it's even better in some cases 👌.

Actually, trying Orcaslicer didn't really help (with scarf joints) because my print had other quality issues, and the real problem was still visible but on the inside!

Using the classic perimeter generator and printing without IS actually improved the situation, but the issue is still very much visible.

[gferon]

I've also made a simple example which demonstrates this issue. bgcode + 3mf files are attached:

I've also tried this one, and I also can see the problematic seam, albeit a bit better than the one print from @stimien.

[kubispe1]

Hi @FutureSharks,
I'm writing to you regarding your recent issue on #11914 (comment)
To help diagnose the problem, I'd like to ask others in the thread if they could try printing your original G-code. My assumption is that you might be experiencing a hardware issue. Here's why:

• The travel movements between perimeters seem minimal, as shown in the image
  
• I printed your G-code myself and didn't experience such a horrible results
  

Could you please confirm if your Prusa Mini is still using the original setup with all the stock components?
Here are some additional troubleshooting steps you could try:

• Have you replaced the nozzle recently (try new original)?
• Have you checked the extruder and tightened any loose screws?
• Have you inspected the long PTFE tube for wear or damage? [BUG] Delayed extrusion after travel when using 0.6 mm nozzle (and 0.4 mm as well) Prusa-Firmware-Buddy#2997 (comment)
• Have you checked PTFE tube to extruders? Under extrusion or gaps at seams with latest versions of PrusaSlicer/firmware #11914 (comment)
• Have you tried to change a filament vendor?
  The problem we're seeing on the Mini is that some HW issues seem to be amplified when using InputShaper.
  I apologize if I'm mentioning some checks you've already addressed.

[SimonTratter123]

I start to think, that this problem is not necessarily a software issue but rather a hardware problem with the Extruder. Because some machines perform good while others do not.

[RenaudILTIS]

Hi @FutureSharks, I'm writing to you regarding your recent issue on #11914 (comment) To help diagnose the problem, I'd like to ask others in the thread if they could try printing your original G-code.

I will try it today and come back.

[RenaudILTIS]

Hi @FutureSharks, I'm writing to you regarding your recent issue on #11914 (comment) To help diagnose the problem, I'd like to ask others in the thread if they could try printing your original G-code. My assumption is that you might be experiencing a hardware issue.

There is a little problem on the seam, and a gap between the infill and the perimeter (the rabbit is small, so it's not obvious, but I have the problem on other pieces).
My filament is Twotrees-HighSpeed PLA, perfectly dry, the room is at 23°C.
The PTFE of the extruder is new (43.4mm).

It's maybe a hardware problem, but my guess is that there is also a software problem.

R.

[joachimklug]

If the issue is hardware related it will be interesting where the root cause is. Most people report the issue on the Prusa Mini. However I definitely see the same issue on the Prusa MK4.

[SimonTratter123]

I just converted my prusa mini to direct drive by designing a holder to put the stock extruder on top of the stock hotend. Print quality much better and the seam problem is gone now:
https://www.printables.com/model/855145-prusa-mini-direct-drive-extruder

[gferon]

I still don't exactly understand how it could be a hardware issue on my MK4, as I'm able to get a perfect result with OrcaSlicer. I need to find a way to reduce the surface of the changes between all of my attempts. Any suggestions?

[FutureSharks]

Thanks for the clear and concise reply @kubispe1 😃

Have you replaced the nozzle recently (try new original)?

✅ Yes I switched to a hardened steel nozzle a long time ago, before this issue came. I could switch back to the brass one if you like?

Have you checked the extruder and tightened any loose screws?

✅ Yes, all look tight.

Have you inspected the long PTFE tube for wear or damage?

✅ Yes, looks like new to me.

Have you tried to change a filament vendor?

✅ Yes. If you see my first post, this model uses multiple colours from 2 different vendors

The problem we're seeing on the Mini is that some HW issues seem to be amplified when using InputShaper.

Makes sense! It could be a combination of the new features and a previously unseen hardware degradation. Using IS printing is MUCH faster.

So I did some extra prints with different firmware and PrusaSlicer versions:

[rtyr]

Yes I switched to a hardened steel nozzle a long time ago, before this issue came. I could switch back to the brass one if you like?

Could you try with new standard E3D brass nozzle?

[FutureSharks]

Could you try with new standard E3D brass nozzle?

I don't have one on hand right now but I can switch back to the original Prusa supplied brass nozzle? It's had little use.

[gferon]

Still trying to print the same cylindrical model, this time with random seams. I still see the same (or a very similar issue). I'll try to slice the model with an earlier PrusaSlicer version like @FutureSharks did. I have done a Pressure Advance calibration and slightly adjusted my value, but this hasn't solved my issue.

[FutureSharks]

@rtyr

Could you try with new standard E3D brass nozzle?

I switched back to the Prusa original brass nozzle, same result. Both that nozzle and my steel one have only extruded about 3KG of spool each, so not loads of use.

[alexchiraples]

Hello everyone! I'm new here.

I didn't give much thought to this problem until my 3D printed toroidal rotors began breaking after just 4-5 uses. Below is my analysis of the issue, and I've achieved improved results by fine-tuning the existing profiles. I've reduced PA from 0.27 to 0.2 and reduced retraction length from 2.5mm to 2mm.
tests.zip - 3mf files

Trial 1	Trial 7

Initial source: Printables - Toroidal Rotor 4 Strong Flying Propeller

Printer: Prusa MINI+, with the original setup and all stock components, purchased a month ago
Firmware: Version 6.0.0
Slicer: Prusa Slicer 2.7.4
Nozzle: 0.4 mm
Filament: Prusament PLA Azure Blue
Filament profile: Prusament PLA

Environmental conditions (according to desk thermometer):

• Temperature: 24°C (accuracy +/- 1 degree)
• Humidity: 46% (accuracy +/- 3%)

No fine-tune

Trial 1

Print settings: 0.15mm SPEED
Source: toroidal_04n_T01.3mf
Notes: bad

Side	Center

Trial 2

Print settings: 0.15mm SPEED, Classic perimeter
Source: toroidal_04n_T02.3mf
Notes: some improvement, bad

Side	Center

Hardware fine-tune (idler screw tension)

Before	After

Trial 3:
Print settings: 0.15mm SPEED
Source: toroidal_04n_T01.3mf
Notes: no change

Side	Center

Trial 4:
Print settings: 0.15mm SPEED, Classic perimeter
Source: toroidal_04n_T02.3mf
Notes: no change

Side	Center

Pressure Advance change

Trial 5:
Print settings: 0.15mm SPEED
Filament Settings: Pressure Advance 0.20
Source: toroidal_04n_T03.3mf
Notes: major improvement, still some under extrusion or gaps at seams

Side	Center

Trial 6:
Print settings: 0.15mm SPEED, Classic perimeter
Filament Settings: Pressure Advance 0.20
Source: toroidal_04n_T04.3mf
Notes: major improvement

Side	Center

Retraction length change

Trial 7:
Print settings: 0.15mm SPEED
Filament Settings: Pressure Advance 0.20
Printer settings: Retraction length 2mm
Source: toroidal_04n_T05.3mf
Notes: major improvement

Side	Center

Trial 8:
Print settings: 0.15mm SPEED, Classic perimeter
Filament Settings: Pressure Advance 0.20
Source: toroidal_04n_T06.3mf
Printer settings: Retraction length 2mm
Notes: major improvement, but trial 6 looks better

Side	Center

[GithubUser99999999]

I got the same problem since Firmware 4.0. Sometimes it's worse than that.

[alexchiraples]

I asked the support today and he suggested to check the length of the Hotends PTFE tube. And mine was only 42mm instead of the 43.4mm on the prusa mini. After replacing it, my mini is printing again with no issues. https://help.prusa3d.com/guide/how-to-replace-a-hotend-ptfe-tube-mini-mini_119449

@SimonTratter123, is this the right way to measure? First time using this tool, feedback is highly appreciated.
Mine is 42.47 mm give or take. Stock hotend PTFE tube. I'll order a new tube, it seems like the stock one has some issues right from assembly.

zero	measure

[mjaschen]

The Hotend PTFE tube will shrink a bit when it is installed as described here and sits pretensioned in that position for a while. I think that's normal and one cannot compare the length of a new tube with one that was in use for a while.

When I measured it was around 41.9 mm in length. I replaced it by a new one ordered at Prusa.

The print results did not change at all.

What helped (as described by multiple people in this thread): lower the Pressure Advance Setting (M572) and decrease the retraction length.

[SimonTratter123]

@alexchiraples The measurement looks good with your tool. When I installed a new PTFE tube, I checked it after the first print and it shrank by ~2mm.
So I do not know why the length has to be so accurate when you actually squeeze the tube in the hotend.

[Fox2wo]

Im also having seam issues with my MK4 with a 0.6 nozzle. Underextrusion for a few mm after a deretraction.

[GithubUser99999999]

I tried using classic perimeter generation instead of Arachne, but that didn't change anything.

[bdwheele]

Is this the same issue or is it something else? This was happening for a while and then was better...Maybe I was just lucky or something.

This is what I'm seeing using

• MK4
• Firmware 6.0.0, PrusaSlicer 2.7.4 with latest profiles
• Overture Matte Filament
• 0.4mm nozzle, 0.2 layer height, speed profile

This is the first few layers of a larger print where I stopped it. Left-to-right:

• input shaper, overture pla profile
• input shaper, generic pla profile
• no input shaper, generic pla profile

Since there was some talk about tube length being wrong I reseated my nextruder just in case, but it didn't make any difference.

[RenaudILTIS]

Is this the same issue or is it something else? This was happening for a while and then was better...Maybe I was just lucky or something.

This is what I'm seeing using

• MK4
• Firmware 6.0.0, PrusaSlicer 2.7.4 with latest profiles
• Overture Matte Filament
• 0.4mm nozzle, 0.2 layer height, speed profile

I have the same problem on the Mini.

I think it's something linked.

[alexchiraples]

@mjaschen , @SimonTratter123 thanks for the feedback and for the extra info!
I've replaced the PTFE tube with the spare one. No change in print after changing the tube but it was a good exercise. This also came with a SuperPINDA probe adjustment.

@bdwheele , have you tried reducing the Pressure Advance (M572 S G-code) and also test reducing the retraction length? Expert mode in Prusa Slicer.
Default Pressure Advance:

Adjusted Pressure Advance (for my environment, hardware fine tune and filament)

Adjusted retraction length (for my environment, hardware fine tune and filament)

Meanwhile, I've moved to Prusament PETG Jet Black, a different animal. Solved the seaming gap with PA and Retraction length adjustments, I had issues similar with PLA. I am now trying to fix perimeters not sticking near the seams and extra stringing, I have over 10 tests for the toroidal sample. Might be that I need to dry my filament even if it was new. Will test that when I have some time.

I am under the impression that the profiles have not been fully calibrated by the PrusaSlicer team with the new PA and IS firmware updates. Maybe it helps if other people confirm with a before and after when changing PA and Retraction length values. I believe feedback from the PrusaSlicer development/support team would be appreciated here.

[SimonTratter123]

I think before the PA and IS update the PA value for prusament PETG was 0.2 while is is now about 0.4

[bdwheele]

@alexchiraples - My M572 settings in filament start GCode looks like:

{if printer_notes=~/.*(MK4IS|XLIS).*/}
M572 S{if nozzle_diameter[filament_extruder_id]==0.4}0.036{elsif nozzle_diameter[filament_extruder_id]==0.5}0.025{elsif nozzle_diameter[filament_extruder_id]==0.6}0.02{elsif nozzle_diameter[filament_extruder_id]==0.8}0.014{elsif nozzle_diameter[filament_extruder_id]==0.25}0.12{elsif nozzle_diameter[filament_extruder_id]==0.3}0.08{else}0{endif} ; Filament gcode
{endif}

Which, if I understand it, would set it to 0.036 for my 0.4mm nozzle. That's 1/4 the value in your example. The value for the 0.25 nozzle is different from the others -- all of the rest of the values have a '0' in the tenth's place. I'm not using that nozzle, but still weird. Maybe the rest of them are wrong?

My retract value is 0.7.