Under-extrusion or gaps at seams with input shaper settings and 5.x firmware  

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

Oh yeah that helped a ton Im saving this. THANK YOU. Im running at 2.4 for the LA and 1.09 for the extruder muliplier. Seems to look great. Just going to try a bigger print now. 

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

After setting the new k factor, this is what I get for seams on small (5.5 mm cylinders on top of a rectangular shape) with Prusament PETG:

This is pretty acceptable to me. Viewed at a distance they can hardly be seen.

Regards,

Mark

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

try turning your detraction setting up a little bit, Im running at 60 and the seams see to look nice. I also ended up not messing with the Extrusion multiplier, just tuned the LA. as mentioned in the article above.  

To me it makes sense if there's a seam if everything is moving faster and the detract speed is set much lower than the retract so when it starts a new layer it takes a second longer to push filament back down. hope this helps.

RE:

In my experience messing with deretraction causes a mess when the print head moves from one object to another. If they could only do it at a seam, it may improve things. Adding 0.75 mm of extra deretraction made the seam on the rectangular part much better, but made the top of the part a fuzzy mess.

My best results were to tune the LA and Extrusion multiplier and live with the seams for now. There are multiple github issues raised for the ugly seams in both the slicer and the firmware, not just for the Mini. I expect it to get worked eventually.

Regards,

Mark

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

I was also having similar issues with the structure and speed profiles with my mini using the input shaper profiles. I tried adjusting zhop, retraction/deretraction speeds, extra length on restart, temperature, wipe, and pressure advance. Lowering the pressure advance did help with the seam at the cost of not having smooth corners and a lot of stringing. Oddly, increasing the temperature gave me a larger Z seam gap, which confused me a bit but probably related to the filament or cooling.

These are the settings that appear to be working right now for my prusa mini with a few mods. I'm using Atomic PLA filament and settings have worked for more than one color from Atomic, but haven't tested on different brands. Hopefully this helps out a bit.

Print Settings:

• Profile: 0.2mm Structural @MINIIS 0.4
• Speed - Infill: 115 (new default on recent update)
• Speed - Solid Infill: 120
• Top solid Infill: 50 (I'm still adjusting this one, but it's more of a preference as the lower temp makes the filament more matte at higher speeds)

Filament Settings:

• Profile: Prusament PLA @MINIIS (modified with the changes below)
• Extrusion multiplier: 1 - default (originally had 1.07 but caused stringing)
• Temperature: 215/210 (default is 230/220)
• Cooling - Min print speed: 35 (not sure this matters just had it on while testing and left it be)
• Retraction Length: 1.4 (default is 2.5)
• Deretraction Speed: 35 (default is 40)

Printer/Mods:

• Prusa MINI+ with 5.1.2 version / PrusaSlicer 2.7.1
• Bondtech IFS Extruder
• Silicone Sock for heat block
• Single PTFE tube from extruder to hot end (instead of 3 PTFE tubes)
• PC4 M10 fittings to allow single PTFE tube
• Adapter for PC4 M10 fittings

RE:

Just an update to this thread, I have done a bunch or hair pulling, printing, failing, and careful experimentation and have now determined that my problems printing 85A TPE have nothing to do with the new firmware or Prusaslicer with regards to underextrusion, or artifacts (I have used no other filament lately). If anything, the shaper might produce nicer prints, but it's difficult to tell. My problems have been and continue to be exclusively the generally poor ability of the Mini to print soft FLEX. Elaborating briefly for anyone stumbling here, the Mini has two critical flaws for printing FLEX: 1) the single geared extruder, and 2) the hotend heat creep and PTFE shrinkage problem. I have upgraded to the Bondtech extruder, which is very nice and probably helps. The only solution, as is for the hotend, is changing out the PTFE tube about every 20 hours of printing, at which point the tube has shrunk over 1mm (out of it's +/- 0.1mm tolerance!). The expensive blue Capricorn tube actually shrinks even MORE than ordinary PTFE, so don't try that with the stock hotend. I am now awaiting my Copperhead heatbreak/nozzle upgrade from Slice Engineering to see if that solves the problem. Good luck to everyone else!

If you are not printing TPE (e.g., even 95A FLEX and stronger), this shrinkage probably doesn't hurt performance for a long time, but FYI.

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

Posted by: @scott-bierly

Just an update to this thread, I have done a bunch or hair pulling, printing, failing, and careful experimentation and have now determined that my problems printing 85A TPE have nothing to do with the new firmware or Prusaslicer with regards to underextrusion, or artifacts (I have used no other filament lately). If anything, the shaper might produce nicer prints, but it's difficult to tell. My problems have been and continue to be exclusively the generally poor ability of the Mini to print soft FLEX. Elaborating briefly for anyone stumbling here, the Mini has two critical flaws for printing FLEX: 1) the single geared extruder, and 2) the hotend heat creep and PTFE shrinkage problem. I have upgraded to the Bondtech extruder, which is very nice and probably helps. The only solution, as is for the hotend, is changing out the PTFE tube about every 20 hours of printing, at which point the tube has shrunk over 1mm (out of it's +/- 0.1mm tolerance!). The expensive blue Capricorn tube actually shrinks even MORE than ordinary PTFE, so don't try that with the stock hotend. I am now awaiting my Copperhead heatbreak/nozzle upgrade from Slice Engineering to see if that solves the problem. Good luck to everyone else!

If you are not printing TPE (e.g., even 95A FLEX and stronger), this shrinkage probably doesn't hurt performance for a long time, but FYI.

Good to know information. I have pretty good results with Sainsmart TPU. Unfortunately, I think you will find that as you make mods to the Mini and it is different than stock, you will have to tune the input shaper yourself, or results will be worse. Prusa has tuned things to compensate for the printer's issues. The farther from stock it is, the more custom tuning will be required.

Prusa definitely does have issues with seams and input shaper. There are several issues raised in GitHub, including some suggestions for improvement, so I hope it will be fixed.

Regards,

Mark

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

Posted by: @lynn

I might be missing the main goal of this thread, but looking at your pics, I immediately think  of improper linear advance settings (pressure advance for Klipper).  The appearance at the seams is the dead giveaway.  On my Voron 2.4 when I went to a higher volumetric flow rates (which happens with the IS profiles), I got prints that looked just like the pics in this thread. Since then I have experienced the same issue on my MK3 when I started pushing the flow rate. I  agree that the presets being provided by Prusa should not have this problem, but if it is a linear advance issue you should be able to fix it calibrating the linear advance settings. The appearance at the seams is the dead giveaway. 

If you decide to look at linear advance, I recommend 

https://ellis3dp.com/Print-Tuning-Guide/articles/index_pressure_advance.html

 

I am using the Prusament PLA @MINIIS profile, which sets pressure advance with M572 S-value rather than linear advance with M900 K-value. I believe the start gcode is setting M572 S0.3 for the Mini with 0.4mm nozzle, whereas the (non-IS) Prusament PLA profile sets M900 K0.2 instead. Unfortunately I don't know enough about these settings to know how to troubleshoot them. Most of my seams are terrible with this profile, although sometimes seams on the outside of a curve turn out fine.

In the linked github issue, there's one recommendation to change perimeters to external first instead of internal first, which seemed to help the person who tried it, but I'd worry that it's just moving the under-extrusion somewhere else.

RE:

I actually have been having this same issue... I did a slow motion video on this problem and the nozzle actually stops extruding, lifts up, moves over a mm or two, and then comes back down and starts the next line. Leaving these nasty big gaps. I still haven't been able to trace why it's doing this. I don't know if it's a setting or a firmware issue.

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

I did some experiments with the M572 settings & found that reducing the S-value helped. I then tried the linear advance calibrator that Lynn recommended and got the above results. The calibrator uses M900 (linear advance) instead of M572 (pressure advance), but I switched between the two and found that the M900 K-values worked well enough as M572 S-values.

The brown print uses the default S0.3 setting from the stock Prusament PLA configs, and in person it looks torn open. The S0.2 seam has a much narrower gap, but it's still unacceptably bad. The S0.17 seam actually looks better in person than it does in the photo. There's no gap at all, only a shallow crease.

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

The is probably a z-lift and retraction between layers or on travel move (especially between two objects that are on longer distance between them), you should be able to find it different settings in PrusaSlicer.

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

1. That's what I thought at first too. But nope, that's not it.

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

Posted by: @mark-3

 

Posted by: @scott-bierly

Just an update to this thread, I have done a bunch or hair pulling, printing, failing, and careful experimentation and have now determined that my problems printing 85A TPE have nothing to do with the new firmware or Prusaslicer with regards to underextrusion, or artifacts (I have used no other filament lately). If anything, the shaper might produce nicer prints, but it's difficult to tell. My problems have been and continue to be exclusively the generally poor ability of the Mini to print soft FLEX. Elaborating briefly for anyone stumbling here, the Mini has two critical flaws for printing FLEX: 1) the single geared extruder, and 2) the hotend heat creep and PTFE shrinkage problem. I have upgraded to the Bondtech extruder, which is very nice and probably helps. The only solution, as is for the hotend, is changing out the PTFE tube about every 20 hours of printing, at which point the tube has shrunk over 1mm (out of it's +/- 0.1mm tolerance!). The expensive blue Capricorn tube actually shrinks even MORE than ordinary PTFE, so don't try that with the stock hotend. I am now awaiting my Copperhead heatbreak/nozzle upgrade from Slice Engineering to see if that solves the problem. Good luck to everyone else!

If you are not printing TPE (e.g., even 95A FLEX and stronger), this shrinkage probably doesn't hurt performance for a long time, but FYI.

Good to know information. I have pretty good results with Sainsmart TPU. Unfortunately, I think you will find that as you make mods to the Mini and it is different than stock, you will have to tune the input shaper yourself, or results will be worse. Prusa has tuned things to compensate for the printer's issues. The farther from stock it is, the more custom tuning will be required.

Prusa definitely does have issues with seams and input shaper. There are several issues raised in GitHub, including some suggestions for improvement, so I hope it will be fixed.

Regards,

Mark

Hey Mark. Well, it's funny when I talk about 85A FLEX/TPU problems in forums, there is often a chorus of "it's easy", or, "you'll figure it out", from people who frequently gain this opinion (and confidence) from printing the ordinary 95A FLEX. Let me assure you, that might as well be PLA compared to 85A, and in particular the horribly inconsistent filament (but wonderful polymer) Ninjaflex. I lucked onto Sainsmart TPU right away, that stuff is just awesome and simple to print, I have many colors and have no reason to try anyone else, highly recommended. Prusa even has a profile for it! Pretty much just choose that profile, figure out the right amount of extruder tension backoff, and it just works, over and over and over, love it! 

By the way, I installed a second Bondtech IFS on my Mini #2, along with the Copperhead heatbreak and hotend as experiment #2. Again, excellent extruder, very easy and it just works (if you get past horrid instructions). The Copperhead--not so much, immediate underextrusion issues out of the box. Perhaps this relates to your warnings about tuning? They claim it is autmatically handled in the latest firmware. Anyway, not happy with it, huge regret and I bought two of them, very expensive!

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

@_kaszpir_, the problem I see as I posted above is you can improve the seams with settings but it makes every other move crap. The settings are universally applied to every move.

@scott-bierly, Printing with the Sainsmart TPU actually got better with input shaping, except for the darned seams. I bought one more color. I don't do a lot of printing with flex. Claiming that a different hot end is handled in firmware is just a cop out with them wanting to sell you something and not have to support it. If it is any different in function, heat transfer, etc., you will have to compensate. I have been reading this forum for about 4 years now, and while not absolutely necessary, the Bondtech IFS is universally liked and people don't complain. Everything I read for every other mod has successes and failures.

Nothing about a 3D printer is easy.

Regards,

Mark

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

@mark, many thanks for the comments, agreed. I print almost exclusively in the Ninjaflex for several years, I don't have much time to read forums unless looking for specific solutions. Yes, it's all such a hot mess, particularly for me doing this. My MK3 originally worked well 3-4 years ago, and then less so after I did the MK3S+ "upgrades", while direct drive should be better, they just don't care about soft FLEX, with the upgrades I was down to about 1 turn of thread on filiment tension, with the slightest deviation (or slip) causing a jam or underextrusion. So, I bought a Mini on a whim not realizing how much impact the Bowden would have, and didn't even know about the half-geared extruder at the time. Yet, it worked great...until it didn't. I spent a long time stupidly tuning every other parameter trying to fix a problem that turned out to be the darned PTFE shrinkage thing. But before figuring that out, in desperation as I had product to deliver, I bought a 2nd Mini! That worked for a while....you get the picture. Now, I know how to fix them both, and ride the curve up and down, but it's exhausting.

Again, sharing this all to help others, but also as a long winded way to ask you (and others) if a better heatbreak or hotend solution exists for the Mini. Beyond that, I think the answer for 85A is a direct extrusion printer that actually thinks through the FLEX problem (why no interest in this Prusa?...and until you sell 85A or less Prusament and tackle these issues, the lack of interest is clear despite the hype), and a hotend that doesn't change properties rapidly due to PTFE shrinkage. LOL, I have a MK4 in a box in the hallway, one of these days I'll see how that plays out...

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

@makr ah ok, thanks for the info

@Scott Bierly could you please provide info why did you hose Copperhead heartbreak vs Bondtech heartbreak for Mini?

Also looks like the design of the Mini was focused on printing basics such as PLA and PETG and this ends in specific technical limitations that get exposed when doing more advanced things such as TPU. Personally I think Mini is just an entry level printer with easy start and learn, and if someone reaches its limitations then don't fight it but should get a different printer.

On top of that some people are just unlucky and get not that great parts or assembly etc and they get much worse experience that they would expect - this is unfortunately inevitable when producing anything en masse, and some units will be just broken or severely underperforming no matter what.

Thankfully there are people that put really a lot of effort to find what is wrong both on Prusa side and forums to identify those issues and provide at least diagnosis or sometimes a fix.

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

Hi @trixie try to set 'external perimeter first' in the slicer, there is onging investigation about thembug doing such mess in prints, and nome users reported that wtihmother slicer you can print same object, and others thatmindeed after changing that parameter you can improve this particular issue. Anyway seems that prusa is already aware of that,

cheers

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

Posted by: @mixer3d

Hi @trixie try to set 'external perimeter first' in the slicer, there is onging investigation about thembug doing such mess in prints, and nome users reported that wtihmother slicer you can print same object, and others thatmindeed after changing that parameter you can improve this particular issue. Anyway seems that prusa is already aware of that,

 

cheers

Yes, I saw that suggestion in the linked github issue. There are other consequences to printing external perimeters first (esp. with overhangs), which is why it is turned off by default. If I recall correctly, older versions of PrusaSlicer did print external perimeters first, and seams often had bulges.

Calibrating pressure advance correctly has already improved my seams greatly. I can still see artifacts in some prints, like small creases, but I prefer that to the bulging seams. Also, I'm confident now that the default pressure advance settings for the Mini are incorrect. I left a detailed explanation as a comment on the github issue. In short: the default Prusament PLA configs use a 0.2 linear advance factor, but the IS profile uses a 0.3 pressure advance factor instead. Linear & pressure advance use the same units and scale, so that number should not increase from 0.2 to 0.3 unless you change the nozzle size or filament type.

I think this explains why people are seeing the problem more when using the IS profiles. Based on my own calibration tests, I think even 0.2 is a little too high, and 0.3 causes extreme under-extrusion.

RE:

 _KaszpiR_

@Scott Bierly could you please provide info why did you hose Copperhead heartbreak vs Bondtech heartbreak for Mini?

Also looks like the design of the Mini was focused on printing basics such as PLA and PETG and this ends in specific technical limitations that get exposed when doing more advanced things such as TPU. Personally I think Mini is just an entry level printer with easy start and learn, and if someone reaches its limitations then don't fight it but should get a different printer.

On top of that some people are just unlucky and get not that great parts or assembly etc and they get much worse experience that they would expect - this is unfortunately inevitable when producing anything en masse, and some units will be just broken or severely underperforming no matter what.

Thankfully there are people that put really a lot of effort to find what is wrong both on Prusa side and forums to identify those issues and provide at least diagnosis or sometimes a fix.

@_KaszpiR_ No info to provide, I surfed a number of these blogs reading about the many people sharing my pain with the PTFE shrinkage and extruder jamming, which of course is just a bunch of anecdotes like  the one I'm typing here 🙂 It seemed people liked the Bondtech extruder, so I tried that, and it's great. You mostly read bad things about any Mini hotend, reviews mixed about the same it seemed between Copperhead and Bondtech, and then there all the no-name Chinese copies on Amazon. I decided to stick with a brand, and since Slice was selling both the Copperhead alone, bundled with their nozzle and silicone boot, AND bundled with the Bondtech extruder, I could do one-stop shopping and it seemed the most credible, if expensive. So, I guessed and chose. Then, brand new and carefully installed, I had underextrusion that stubbornly resisted responding to increased extrusion multiplier. Oh well.

Hey, Prusa boldly states, even today, on their *latest updated* web page:

"The MINI+ is a fast and reliable printer, excellent for both beginners and advanced users looking to build a printing farm."

"The Original Prusa MINI+ is a smart, compact and fast 3D printing workhorse, equipped with all the bells and whistles you've come to expect from an Original Prusa 3D printer."

"It’s packed with many of the features you can find in its larger siblings"

"Supported materials Wide range of thermoplastics, including PLA, PETG, ASA, ABS, PC (Polycarbonate), CPE, PVA/BVOH, PVB, HIPS, PP (Polypropylene), Flex, nGen, Nylon, Woodfill and other filled materials."

"Max nozzle temperature 280 °C / 536 °F"

I'm not arguing with your conclusion at all, countless hours of pain and suffering later, it is proven true. But, they are selling it as above, that's the problem. Imagine all the kids and non-technical people buying one of these on the hype, I just think the situation needs to be more honest. And, Prusa could very easily come up with in-house improvements we can trust, offer them as priced upgrades or mod kits, then they can sell a cheap PLA Mini, and a slightly higher end Mini that can fulfill their hollow promises. 

Also, this hotend PTFE issue can cause jams for everybody including PLA at some point, it seems, yet they don't address it. And for NinjaFlex, my point was that even the MK3 falls short for many of the same reasons, both extruder and hotend. I probably should not have bought the MK4 without vetting this more, I hope it is a better solution to all things, but I'm worried, their main obsession appears to be speed printing, which is great, but we need quality and reliability first.

RE: Under-extrusion or gaps at seams with input shaper settings and 5.x firmware

Fair points.

The more I read about Mini and its issues the more I wonder how many people are happy with it va not so lucky ones. I believe the unlucky ones tend to generate more messages related to issues than the people that have no problems ( as is when you get into the hospital you see a lot of sick people because healthy ones does not have to be in the hospital).

What I can say is that my printer works no buses so far but my usage is quite limited.