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

• [X] Project file
• [X] 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

https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/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.

[andrewmeyer]

Its not unique to Prusa firmware, I am encountering the same issue on a klipper printer, I'm hoping there is a fix soon.

Another post seemed to suggest setting "extra length on restart" to 0.06 (0.15*0.4) but this looks like it only applies when a toolchange is performed, not on a move

[bszonye]

@mimeister I'm seeing this problem with the Prusament PLA @MINIIS profile, which uses M572 pressure advance instead of M900 linear advance. The start gcode:

M572 S{if nozzle_diameter[0]==0.6}0.17{elsif nozzle_diameter[0]==0.8}0.12{elsif nozzle_diameter[0]==0.4}0.3{elsif nozzle_diameter[0]==0.25}0.85{else}0{endif}

The M900 gcode that you quoted does appear in the more general Prusament PLA profile, but that one excludes MINIIS in the compatible printers condition, so normally it's not selectable with the IS profiles. (The general profile does have a clause for IS that is identical to the @MINIIS version, so I'm guessing that you'd get the same behavior if you forced the slicer to use it.) If I understand the start gcode correctly, it's using M572 S0.3 for a 0.4mm nozzle.

I've been reading about the two systems, and it seems that M572 S-values are very similar to M900 K-values, but I don't know how to tune them. I might try switching to external perimeters first, as I'm not as worried about overhangs as these terrible seams, although I'm worried that changing the print order will just move the under-extrusion somewhere else.