cant solve stringing issues

[ndsugi 3]

I have calibrated e-steps, temperature, retraction, print at 50 mms, usually .12mm layer height, retraction on, tried different filaments, but all my otherwise great print tests for executing small details have been sabotaged by this persistent stringing issue.  I'm using a .4mm nozzle, slicing in 5.1.  Is there any other settings I should be paying attention to?

[Smithy 1,144]

Which filament?

[yuriy22 0]

hi ndsugi,

 

it looks like this might be a problem with Cura 5.1--we're observing the same problems. try to slice in a previous Cura release

[ndsugi 3]

Using Pla.

 

I'm sort of glad to hear its 5.1, as ive tried everything, every setting, temp calibration, flow, retraction calibration, e steps etc.

 

Have you talked to anyone official regarding this?  How many other users are having these problems?

 

 

 

[GregValiant 1,318]

Can you post one of the problem models?  It would be even better if you could load one of those models, set Cura up the way you like, and use the "File | Save Project" command and then post the 3mf file here.

 

I've moved to 5.1 exclusively and I haven't had any issues like that.  I do tend to print more mundane mechanical things and they don't generally have spires or minarets but they often have several islands that the nozzle has to move back and forth in order to print them.

[ndsugi 3]

Ok here goes, it's my birthday tomorrow and I would like nothing more than to get a perfect print!

 

btw Here is a few other photos of my offset calibration which appears to have good z offset at some points while problematic at others, and also a bed leveling calibration shape showing huge problems on the left side of the plate (photo is flipped), I could barely clean the filament off.  I have opened a ticket with anycubic to see if that is a manufacturer issue or something on my end.

 

I tried cura 5.0, and much less stringing, but also had to stop and restart the print 3 times because the hotend was moving 

around like it was working but no filaments was coming out.  Final photos show that calibration model w/ 5.0.

 

Not to add too much to the list.. but when a-bing my print to a mk3s+ print with as identical settings as possible, i noticed the mk3 has such better detail and definition, especially how it prints the letters first layers allowing full clean separation in the lettering.  How can I increase my detail and overall quality?  

 

AKMAX_3D_test_V3_0.4mm.3mf AKMAX_simple_boat5.3mf AKMAX_Z_Offset_Test.3mf

Edited August 11, 2022 by ndsugi

[ndsugi 3]

here's the a-b comparing my kobra plus w/ Cura profile to a mk3s+ w/ prusaslicer.  Very similar profile settings, nozzles both .4 set to .1mm layer height for the test.

 

 

 

[FaithV 0]

Hey! I was having the exact same probs. try adding a raft, that will help w/ it sticking to the plate, and will also

stop almost all of the stringiness.

 

 

[ndsugi 3]

Ok so, i have made considerable progress, switched to 5.0 from 5.1 made a difference for some reason, found .2mm z offset in cura was needed, extruder knob needed to be tightened much higher than the manual recommended, few other settings tuned, swapped to a e3d nozzle x steel, calibrated nozzle and bed temps, tested many filaments with different temps to make sure its not that, (steel nozzle allows for almost any temp without stringing on the tower test??  yes the temps were changing per layer i was watching).    Retraction and retraction speed tower tell me my settings are good...

 

lovely quality on most surfaces but im still really stuck on getting these blobby, stringy issues resolved as i believe this printer should be able to do better from other prints I've seen.  Temp for this was 200, speed 50, pla, all the usual suspects for reducing stringing and heightening detail were on in cura.  Can someone suggest what I may be missing?  

[GregValiant 1,318]

How is your layer cooling fan working?  I ask because the tops of the windows of the second deckhouse are really sagging and things like the radar dish on the roof don't look too good either.  

I thought I had posted these but it was late and I must have forgotten to hit the submit button.

Neither of these have the "saggy" windows that you are getting.  I have a single 5015 bolted to the side of my Ender 3 Pro.

These are with some old PLA and it could have stood some drying out.

 

PrusaSlicer

 

Cura

[ndsugi 3]

They seem to be working fine, but good point.. they are dual 4010 fans however i found a guy saying that they aren't directing the cooling very effectively, im gonna print these out and try them.

 

https://thangs.com/designer/MandicReally/3d-model/Anycubic Vyper %26 Kobra Max Part Cooling Duct UPGRADE! - Improved print quality-68268

 

also found these, if you suggest maybe upgrading the fans?  will better cooling give me less stringing and higher detail accuracy?  

 

https://thangs.com/designer/goldingr6260001/3d-model/Kobra Max Hot End Shroud.stl-205780

 

another: 

https://www.printables.com/model/217846-vkd15-kobra-max-vyper-dual-5015-part-cooling-shrou

 

 

[FaithV 0]

Have you tried adding tree supports in the windows and door? it looks a lot like it is trying to build up, but is having trouble with going up without supports, tree supports are some of the easiest to remove. If you are in a hurry sometime, and it does that, you can just use a nail file or sand paper to get rid of that.

[FaithV 0]

if my tips earlier did not help, here is a link for an article that I found about stringing issues...

 

https://support.ultimaker.com/hc/en-us/articles/360012016280-How-to-fix-stringing

[ndsugi 3]

On 8/13/2022 at 4:30 PM, GregValiant said:

How is your layer cooling fan working?  I ask because the tops of the windows of the second deckhouse are really sagging and things like the radar dish on the roof don't look too good either.  

I thought I had posted these but it was late and I must have forgotten to hit the submit button.

Neither of these have the "saggy" windows that you are getting.  I have a single 5015 bolted to the side of my Ender 3 Pro.

These are with some old PLA and it could have stood some drying out.

 

PrusaSlicer

 

Cura

 

 

So i've printed out and installed some fans shrouds (from the first link) to see if it would have any difference, and it's kind hard to say, perhaps it's even worse?  I have started printing just the top of that boat benchy because I'm getting perfect results in all other areas except the top most portion.  

 

I wonder if maybe i should consider getting some 5010 fans to replace the stock ones, there is actually 3 fans but I don't think they are positioned very well. 

 

But! Before I do that, anyone who has good experience with Cura and has dialed in their own profiles for quality over speed, and doesn't mind taking a look at what I've been working with in my own custom profile.. would be much appreciated.  I just spent the evening swapping filaments, turning off/on z-hop, changing retraction up and down, experimenting with the extrusion distance window, testing maximum resolution/deviation, trying upping and lowering temperatures, speed.  I really just want to know if this is my profile or if it's either - fans not doing there job cooling the finer detailed parts, or my extruder is perhaps not working consistently and smoothly.  If it's a minor upgrade I need to consider I have sunk so much time into the damn thing I wouldn't mind seeing it through... and then next time never buying one of these ever again.  For the record, everything else seems well calibrated, z-hop is dialed in to give beautiful first layers, tensions on belts seem to be where they need as far as I know.  

 

What is killing me is seams ruining the details, stringing in between those details, sagging windows/ladders like Greg mentioned, rough edges again from seams.  I've seen what some lower end non-Prusa printers can achieve so I know i should be able to get myself sorted..

 

Here's the profile:  Printer is a Kobra Plus, .4mm e3d nozzle x, range of filaments that seem to work fine on my uncles MK3s+ i use as a control.

ndsugiCuraProfile.3mf

[GregValiant 1,318]

I opened that last 3mf file but I don't have the proper printer definition file and so I didn't get the printer or the settings.  What I've done is used your sunken ship model and set up Cura the way I want and saved it as a 3mf project file.  Opening it as a project will install an Ender 3 Pro in Cura but it's the settings profile you want.  After you have it you might have to export it and then activate your printer and import the profile.  I'm not sure on that.

The print temp is 210, bed 60, speed 50 with outer walls at 35, retraction 6.5 at 35mm/sec.  No retract at layer change or before the outer walls, Z-hop is off.  Line width is .35 on a 4.0 nozzle and minimum line width is .30.

 

Layer cooling blowers:

A decent quality ball bearing 5015 (Delta, Sunon, etc.) will move a lot of air.  That fellas comment about aiming the air is on the money.  That is one of the shortcomings of the 4010 Ender 3 layer cooling blowers as the exhaust duct is totally wrong.  (That and they are noisy and the sleeve bearings wear out in a hurry.)

This is the design I came up with for my Ender 3 Pro.  I wanted to be able to see what was going on at the nozzle so I wrapped the duct around the back.

I'm not a fan of some of the gigantic shrouds I've seen people hang on their poor print heads.  Better to have a single fan that just works well than multiple ones that are fighting each other.

When I run this at 100% and I'm printing at 100mm/sec the nozzle can throw a roostertail.  It isn't really stringing but more like cotton candy.  Light fibers of filament that I can barely grab.  Not a lot of them, but they are  annoying.  The cover on the hot end fan keeps the crap out and does a nice job of quieting the fan.

 

 

 

 

GV_Cura_Settings.3mf

Edited August 16, 2022 by GregValiant
add attachment

[FaithV 0]

wow, when I opened it in my Cura 5.0 I saw a lot of red spots. Even more in the parts like the windows and door, so would tree supports help??

[ndsugi 3]

hey FaithV, I appreciate the consideration but that's not the issue here, as this is a benchmark test print, meaning its meant to test certain parameters and surfaces to calibrate your printer and profile.  

 

You're just barely beginning your super-fun-totally-not-at-all-tedious Cura learning experience, I think you should maybe wait a little bit until you feel yourself ready to offer advice.  No hard feelings just a friendly suggestion.

[GregValiant 1,318]

@FaithV as a glorified Benchy boat then supports would be considered cheating.

 

If you look at the two red ones I printed - other than some stringing (not my gcodes) they aren't bad.  I'm still tending to think it's a cooling thing.

Hopefully @ndsugi will get it sorted out before he decides to try out for the UM Forum "How far can I throw this @#%#$ printer" record.  The reigning champion is an Xvico.

[ndsugi 3]

thanks for the profile @GregValiant, i am currently printing a few tests off as we speak.. and they look good so far. Noticed you have bridge settings off, and coasting off as well, do you prefer it like that or is it very project based?  I figured bridge settings enabled would help with drooping overhangs.

Edited August 17, 2022 by ndsugi

[GregValiant 1,318]

I enable the Bridge setting occasionally.  Yes, it depends on the model.

I've been dropping the Support Flow and Support Interface Flow to 90% (85% for red PLA for some reason) and the weaker supports make them easier to remove and the roof doesn't stick to the interface as well.  Setting the Support Bottom Distance to 2X layer height allows them to break away pretty clean as well.

I never use Coasting as (with my printer) it tends to cause under-extrusion when it starts up again.  That lead me to experiment with Extra Prime after Retraction but I found it left too many blobs when it wasn't needed and that turned out to be most of the time.

Your boat is pretty good for checking stringing.  I came up with these two calibration models.  The "Calibration Shape" is good for walls/Zseam and also works pretty good for checking "Spiralize".

The other is for Supports.  Getting the supports out of that model is also a test.  You better have the right Picks and Pliers for that one.

You can scale them to get different effects. 

For a speed test I take a regular calibration cube, scale it to 200 x 200 x 1mm (or nearly as big as your build plate) and set the "Top/Bottom Line Directions to [0] and the print speed to 100.  That will put all the Skin extrusions on the Y motor.  Setting the Line Directions to [90] will exercise the X motor.  At any rate, tuning the feed rate is easy as 50% would be 50mm/sec, 120% is 120mm/sec.  Skins (and a magnifying glass) are also the best place to evaluate your overall Flow and consequently your E-steps/mm.

At just over 175mm/sec my Ender starts to have extrusion problems.  I think it's because the Accel setting on the E motor means it doesn't get going fast enough.  During most of the run it's OK but starting out there isn't any plastic for the first 5mm or so.  I never print that fast but it's a slightly interesting data point.

This is all part of that "super-fun-totally-not-at-all-tedious" thing you mentioned.  I can't see from here of course but I assume you had your tongue firmly planted in your cheek.

 

GV_SupportShape.stl GVCalibration_Shape.stl

[ndsugi 3]

@GregValiant you're an angel, I was very close to entering this years UM forum printer throwing contest.  I copied your profile, but kept some from mine and voila!  Amazed that it works so clean, no more drooping, minimal blobs, nearly no strings at all!  Small details are amazing, although things like the tiny satellite dish on the boat roof still look all mushy, compared again to the mk3s.  But everything else is actually better than the results on my uncles prusa, even less stringing and better detail clarity, especially on the ladder and the itty bitty box on the left side.  And this was .2mm!  I think I prefer .12 or .14mm but its hard to distinguish aside from the texture produced for subsequent painting. 

 

I really wish i knew what exactly it was that made such a difference, I was wondering about acceleration control being enabled at 1000% for most parameters, this seems to make my print head move much more like the prusa, fast and efficient, which may reduce stringing as well?  Could be turning zhop, coasting and bride settings off, but to be honest i dont want to go back to the 9th circle of calibration-hell, I am an artist afterall and really am happy to finally get back to sculpting and hopefully producing some nice finished work.  

 

If you have any idea about getting that mushy tiny top most part dialed in, please let me know, otherwise thank you again so much for the assistance.  I need to make a consolidated post about the kobra Plus/max as there have been many steps necessary to get this to print as i like and your profile suggestions have been the final touches.  

 

heres some photos, you can see the succession of melting-blob-boats to the final red boat (sorry red doesn't photograph so well for detail).

[GregValiant 1,318]

Nice job getting it dialed in.

People have come here (and on Github) with "profiles" that have different speeds and accelerations for every single setting.  They vary the line widths for everything.  Consequently it's hard to see what's going on as the flow through the nozzle is all over the place.  There is a lot to be said for keeping things simple because getting a model right and getting a complicated program like Cura to do what you want, and then dialing in a robot on top of all that  - it ain't easy.

 

So for being a good listener you get "Greg's SD Print Tool".  It's a small Windows application for communicating with your printer over the USB.  It controls printing from the SD card, all the tuning functions, homing, leveling positions, calibrating the E-steps, PID tuning, and some other things.  The only thing you need to do with the knob on the printer is to "abort" a print.  It's an unsigned app so if you decide to install it you have to fool your anti-virus into allowing the install.  There is a readme file and there are tooltips on the controls.  It isn't rocket science to get it to work.

 

Greg's SD Print Tool