Jump to content
Ultimaker Community of 3D Printing Experts

Messy exteriors and unsightly Z-seam with Overture PETG (Ender-3 S1 / Cura 5.0.0)


Recommended Posts

Posted · Messy exteriors and unsightly Z-seam with Overture PETG (Ender-3 S1 / Cura 5.0.0)

Hi all,

 

I recently switched over to Cura 5.0.0 and I've been struggling to clean up the PETG prints out of my Ender-3 S1 with a full metal hotend. This prints themselves look mostly good but I'm seeing all kinds of surface artifacts that I believe are temperature and/or travel related. The Overture gold PETG I'm using prints rather hot and anything lower than a 240C nozzle temp has caused bad underextrusion at the layer start points and brittle parts. With my present settings, right now the most visible issue is the Z-seam which looks like a complete mess on the cylindrical portions of the part I printed. The seam feels slightly raised when you run you finger across it, like it's slightly overextruded and it leaves this "shadowy" artifact as it progresses into the layer which you can hopefully better see on the areas I highlighted in the photos, especially the Benchy. On the larger part, the far right cylinder has a ton of rough surface imperfections following the Z-seam. Based on the how the printer behaves before the print starts; it oozes over an inch of filament that I have to quickly swipe away before the print starts, I wonder if I'm printing too hot/cooling too much or need to try adjusting my retract/prime settings or enable coasting.

 

The second issue is there is a lot of small raised blobs between the cylinders on the large print, as well as lots of smooth holes/bubbles in the layers all over the print. The bubbles have persisted even at lower temps so I halfway wonder if they're a filament drying issue (I did dry this roll initially, but it has been sitting on the printer for a few days now), or if it's related to retraction/travel or overlap setting. The blobbing I'm less sure about. It only occurs on the cylindrical sections next to the center bracing piece on the part and they occur in a repeating diagonal pattern until the bracing piece ends.

 

There's a lot of variables at play here and I'm not really sure where to start since I'm still fairly inexperienced at 3D printing. What might be some solutions here? My relevent slicer settings and Cura profile are below. 

 

Thanks!

 

Settings:

  • Printing Temp:  245C
  • Bed temp: 75C
  • Flow: 80%
  • Initial layer flow: 100%
  • Layer height: 0.2mm
  • Wall thickness: 1.2
  • Wall line count: 3
  • Z-seam alignment: Sharpest corner
  • Seam corner preference: Hide seam
  • Top/bottom layers: 5
  • Skin overlap percentage: 10%
  • Infill: 20% Cubic
  • Infill overlap percentage: 20%
  • Print speed, infill speed: 30 mm/s
  • Wall, Top/bottom, initial layer speed: 18 mm/s
  • Travel speed: 150 mm/s
  • Acceleration control: On (defaults)
  • Jerk control: On (default)
  • Retract at layer change: No
  • Retraction distance: 1 mm
  • Retraction speed: 45.0 mm/s
  • Prime speed: 90.0 mm/s
  • Retraction minimum travel: 1.5 mm
  • Retract before outer wall: Yes
  • Z-hop: Off
  • Fan speed: 40% (0% on initial layer)

20220730_120649.jpg

20220731_121528.jpg

20220731_121039.jpg

20220731_143522.jpg

PETG Test New.curaprofile

  • Link to post
    Share on other sites

    Posted · Messy exteriors and unsightly Z-seam with Overture PETG (Ender-3 S1 / Cura 5.0.0)

    Look at the Mesh Fixes section of settings and find the Maximum Resolution.  The default for most Creality printers is 0.4.  What is your setting?

    A higher number will have the effect of lowering the print resolution by combining short line segments into longer ones.  If Cura chops a circle into a bazillion extremely short line segments then the printer might have to pause for a couple of micro-seconds and that can cause a little blob each time the nozzle hesitates.  With a higher maximum resolution it takes less lines of gcode to describe the same geometry and so the printer doesn't get bogged down waiting for the next gcode line to get translated.

    The warping on the bow near the build plate is probably a cooling issue.  There is a slight overhang there and so a feather edge gets created for a few layers.  It curls up a bit and then the nozzle knocks it back down.  The result is often a defect.  About all you can do is make sure the layer start and stop point and the Z seam are someplace other than the front of the boat.  The port or starboard corners of the transom would be better choices (I'm being nautical).

    Your flow at 80% would seem to indicate that your E steps aren't calibrated correctly.  PETG or not, having to force a 20% under-extrusion like that isn't really where you want to be.  I print a lot of PETG and at 105% flow it looks much like PLA at 100% when I put a sample of each side-by-side under the microscope.

  • Link to post
    Share on other sites

    Posted (edited) · Messy exteriors and unsightly Z-seam with Overture PETG (Ender-3 S1 / Cura 5.0.0)

    The maximum resolution is set at 0.25 right now. Out of curiosity, are there any cases where you'd want this to be set low? Maybe for a high detail print? Or is one value typically good for most applications?

     

    Regarding the Benchy; I did initially have the corner preference setting on smart hiding for a previous Benchy and it generated that nasty Z-seam that ran about halfway up the bow (see pic) along with the kind of haphazard placement of the seam along the stack. Hide seam made the one I posted above a lot better looking visually like you said, since the seam is now along one of the back corners but I still got that warping in the bottom of the bow. I will say, having run temp towers on this specific PETG; it loves to curl on thin overhangs regardless of what temp I print it at. I'm still a bit perplexed on what's considered ideal cooling for this stuff. Everybody seems to have a different take: no fan, a little fan, or full fans. Of course it all depends on the exact filament and fan setup, but what's considered generally correct? Is 40% fans for PETG too much? Too little?

     

    The flow calibration was done per Teaching Tech's guide with the vase cube, and because I wanted to improve dimensional accuracy. However, like cooling PETG, I see a lot of mixed opinions on if messing with flow is a necessary/good thing or not. I had it initially set to about ~72% (I was getting roughly ~0.52mm on a 0.4mm line width setting) but I was having issues with my walls not sticking to each other, so I gradually bumped it up to 80% to try and alleviate that. The E-steps were calibrated since I replaced the hotend though this time around I did it with the nozzle removed and it was only slightly off from what I had it set to previously. That said, I probably shouldn't be doing it with the whole Sharpie + ruler thing if I'm going for utmost accuracy. 

     

    20220731_181224.jpg

    Edited by YALE70
  • Link to post
    Share on other sites

    Posted (edited) · Messy exteriors and unsightly Z-seam with Overture PETG (Ender-3 S1 / Cura 5.0.0)

    I have a good rant on single wall "calibration" cubes around here someplace.  The bottom line is that if you calibrate for a single wall model you will be able to print perfect single wall models.  On all other models the flow will be wrong.  How many actual single wall models do you print?

    Calibrate your E-steps.  Scale a calibration cube to 100 x 100 x 1mm tall and print it.  The skins are the best indicator for flow and let your own eyeballs see what's going on.  You can tweak the flow using the LCD as it prints.  It will be darn close to correct at 100%  flow.  I calibrated my Ender for PLA and I have found that PETG is better at 105%.

    (BTW I picked up a microscope at a garage sale.  It's really good for inspecting prints but a magnifying glass ain't bad.)

     

    Regarding cooling.

    As you've no doubt found, PETG is prone to warping.  Certain shapes are worse than others.  If you have a section that is long, narrow, and fairly tall then you know it's going to lift.  I often design elephant ears into my prints to help hold them down and I always use a fair coating of hair spray as an adhesion promoter because I've found it's a must for PETG on the glass bed.  There is a plugin in the Cura MarketPlace called "Tab Anti-Warping" that you can use on corners of your print to help keep them from lifting.

    The bed is hot and so there are often problems with curling near the bed.  Once you get up higher you can start to use some fan.  At what layer and how much fan depends on your own system.  I designed a single 5015 system for my Ender and it's pretty good so about 40% works well for PETG.  I also wrote myself a post processor to add cooling profiles to gcodes.  I check the preview in Cura and then build a profile that turns the fan on and off at specific layer heights.  That works quite well but it wouldn't work for just the bow of the Benchy.

     

    This print is a shark fin in PETG.  It's long, narrow, and tall.  Even with the tabs it pulled their middle area up almost a millimeter.  (It's paused here as to slide a 4mm x 225mm steel rod down a hole on the inside to keep it from warping.  I mounted these on the roof of our SUV so we could find it in parking lots.  The sun is tough in Florida.)

    DSCN2810.thumb.JPG.a6b940bae98a380a5c6a77fb28f58ad7.JPG

     

    Here you can see how hard it was pulling.  I used a simple cooling profile on this as only the tip at the top really needed it.  

    DSCN2814.thumb.JPG.feef07d8a8dab735ea7c73c009468c2c.JPG

     

    The cooling profile thing is part of this modestly named app - Greg's SD Print Tool which you only get if you throw away those single wall calibration cubes.

     

    I went into another rant and almost forgot one of your questions.

    When Cura does a slice there can be line segments in the range of microns.  Each of those line segments takes a line of gcode to print it.  That's the resolution we're talking about rather than the overall resolution of the model (which is a function of the STL, 3mf, OBJ, etc. file).  So the Maximum Resolution needs to be tuned for your printer so it can run smoothly around circles and curves while keeping up with all the calculations it needs to make.  The longer a line is the more time the printer/planner has to calculate the next move.  At some point we need to remember that we're talking about molten plastic here so whether an extrusion is .00001mm long or .1mm long are you going to notice a difference?  You will if it stutters and leaves blobs while it's trying to process all those .00001 long lines.

    Edited by GregValiant
  • Link to post
    Share on other sites

    Posted (edited) · Messy exteriors and unsightly Z-seam with Overture PETG (Ender-3 S1 / Cura 5.0.0)

    Gotcha. I can't say I've been convinced flow calibration was doing much good since it mostly makes my top skins look like garbage unless I increase it (I keep the initial at 100% for adhesion... which I'll get to in a second). I do get sharper corners out of it though; normally they bulge a bit, though in most cases I'd imagine that's a problem better served by linear advance. Which I can't do (at least not easily?) because of how Creality decided to configure the stepper drivers on the S1. I guess it's more of a band-aid than an actual "fix". I'll give the E-steps another once over. This time with a pair of calipers and a sharp hobby knife instead of fudging it with the Sharpie haha.

     

    RE Warping/Cooling:

    Looking at the Benchies again, definitely not a flat first layer. Not even close. If you put the three I have with this filament on a flat surface, the bottoms are all slightly bowed out, especially in the front. I wouldn't be shocked if that weird warping area that's consistent between the three just cascades from that initial, barely perceptible curl. Honestly though, I find myself having problems with my prints sticking too well to the bed, just not everywhere it seems. I've ruined my second spring steel build surface, partly because I was an idiot but it pulled chunks of the coating right off it. I did try the spare glass bed I have after the first spring steel surface bit the dust, and I'm certainly not trying that again without a layer of glue stick. First layer tests stuck to that thing like they were JB Welded to the surface. 😩

     

    RE Maximum Resolution:

    How do I go about calibrating/tuning that? Based on the stuff I'm seeing out there, increasing those values should hopefully improve a good chunk of the weirdness on the exterior. I also found the Arc Welder plugin which looks like it would accomplish a similar end goal. (GitHub - fieldOfView/Cura-ArcWelderPlugin: Cura plugin which wraps ArcWelderLib to convert multiple G0/G1 moves to G2/G3 arcs.)

     

    Also, I appreciate your detailed responses. I wasn't expecting this hobby to be a walk in the park but man, I feel like I need all the help I can get at this point (I was trying to get help from Reddit prior, which... yeah). Thanks a lot!

     

    Edited by YALE70
  • Link to post
    Share on other sites

    Posted · Messy exteriors and unsightly Z-seam with Overture PETG (Ender-3 S1 / Cura 5.0.0)

    FieldOfView is  @ahoeben on this forum and is the implementer/expediter/part-author(?) of the ArcWelder.  He will have a better take on the Magic involved.

     

    To use ArcWelder, the firmware of the printer must support G2 (CW) and G3 (CCW) commands or it won't understand them.  In regards to the G2/G3 commands within Marlin firmware there is a setting for "MINIMUM_ARC_SEGMENT_LENGTH" and the default is 1mm and that would be the "Movement Resolution".  That would compare to the "Maximum Resolution" setting in Cura.  I think that pipe organ looking print would benefit from either ArcWelder or a higher Max Resolution setting.

     

    Regarding Max Resolution you want the lowest setting that allows your printer to move smoothly without stuttering.  Once you have it where you like it then you can leave it alone.

     

    Stick the glass plate and model in the freezer for 15 minutes.  I pop the prints off using the putty knife that came with my printer, and a tack hammer (A LFH as opposed to a Harley Tool which is a BFH).

     

     

  • Link to post
    Share on other sites

    Posted · Messy exteriors and unsightly Z-seam with Overture PETG (Ender-3 S1 / Cura 5.0.0)
    4 hours ago, GregValiant said:

    He will have a better take on the Magic involved.

    No, not really.

  • Link to post
    Share on other sites

    Posted (edited) · Messy exteriors and unsightly Z-seam with Overture PETG (Ender-3 S1 / Cura 5.0.0)

    So, quick update on what I've done. I bumped my maximum resolution setting from 0.25 to 0.5 and installed Arc Welder. I also set up the glass bed and put down a layer of glue stick. No other changes to the setup. First thing I did was print another Benchy and there wasn't a noticeable change in quality. The first layer was more flat but there was still the same warping on the bow, holes all over the walls, and the weird extrusion artifact after the layer start point. You can see it in this picture; the off-colored regions the left of the opening in the cabin:

    20220801_183004.thumb.jpg.825bc19f38dd33e22efcab285a02fc18.jpg

    Other than that, it's an okay Benchy. I'll at least be able to print something functional with a little bit of post print cleanup, though it won't win any beauty contests (which kind of defeats the purpose of having a snazzy gold filament imo). I decided to devote my attention to fixing those stupid tiny holes in the wall for the time being and printed six AA battery sized test cylinders to try and nail what the cause was:20220802_173108.thumb.jpg.d26694960c030737953b0246d465850a.jpg

    From left to right:

    1. Temp: 245C, Flow: 80%
    2. Temp: 245C, Flow: 100% (No discernable difference)
    3. Temp: 245C, Flow: 100%, Retraction: Off (No more holes!)
    4. Temp: 245C, Flow: 100%, Retraction: 0.6mm (Still no holes!!!!)
    5. Temp: 245C, Flow: 100%, Retraction: 0.8mm (Holes started to appear, so back to 0.6)
    6. Temp: 240C, Flow: 100%, Retraction: 0.6mm (I was able to break this one in half, so back to 245C)

    So the holes were caused by having too high of a retraction distance, though there might be more to it like retraction/prime speeds but I don't really want to crank those lower if I can help it. The Z seam is unavoidable on these cylinders, but I'll just have to move them in practice. Also @GregValiant, going to 100% flow did not seem to hurt anything like you mentioned. I guess it's kind of funny that they have you nail the flow percentage with a vase cube, but if you see underextrusion on an actual model (which, you probably will), the solution is just to turn it back up again. So... what's the point? I'll have to try the bigger model again once I fix the STL since I messed up the dimensions, and maybe another Benchy before that.

     

    EDIT: I'm actually going to call it quits with this specific PETG spool. I tried printing some smaller, more thin prints with it after my initial conclusions and the layer adhesion is still way too weak. I'm not sure I want to keep raising the temps in search of that number for ideal strength, especially not when the best I can get away with is 0.6mm of retraction. Oh well. Time to roll the dice with another brand I suppose.

    Edited by YALE70
  • Link to post
    Share on other sites

    Posted (edited) · Messy exteriors and unsightly Z-seam with Overture PETG (Ender-3 S1 / Cura 5.0.0)

    Here's how I do most PETG models.  In this particular case I wanted the fan to come on when the inside deck printed so I added the Search And Replace to take care of that.

    SSGregSpFish.3mf

    I started out printing PETG at 235 but after doing a temp tower I've dropped it to 225.  It isn't near as soupy.  Retraction is 6.5 and print speed 35 with the outer walls at 30.  Flow is 105% with the supports at 100%.

    I got sick of printing the same Benchy all the time so this is the Sport Fisherman version.  The filament is the MH Build series (the cheap stuff) from Matter Hackers.

    DSCN2960.thumb.JPG.76ef82715f8c39baadb527aa59a9fe01.JPG

     

    DSCN2958.thumb.JPG.94244c8803a77aa01d8649023b2e4c93.JPG

    Edited by GregValiant
  • Link to post
    Share on other sites

    Posted · Messy exteriors and unsightly Z-seam with Overture PETG (Ender-3 S1 / Cura 5.0.0)
    11 hours ago, GregValiant said:

    Here's how I do most PETG models.  In this particular case I wanted the fan to come on when the inside deck printed so I added the Search And Replace to take care of that.

    SSGregSpFish.3mf 4.81 MB · 1 download

    I started out printing PETG at 235 but after doing a temp tower I've dropped it to 225.  It isn't near as soupy.  Retraction is 6.5 and print speed 35 with the outer walls at 30.  Flow is 105% with the supports at 100%.

    I got sick of printing the same Benchy all the time so this is the Sport Fisherman version.  The filament is the MH Build series (the cheap stuff) from Matter Hackers.

    Yeah at 225-235C with the gold Overture PETG, I'd be able to pull the layers apart with little to no effort. I'm honestly convinced the stuff is kind of garbage. Maybe it's the "silk" elastomers in it giving me trouble? I ordered a spool of orange Hatchbox PETG so I'll try things out again once that shows up.

  • Link to post
    Share on other sites

    Posted · Messy exteriors and unsightly Z-seam with Overture PETG (Ender-3 S1 / Cura 5.0.0)

    I have to print the silky PLA's hotter and the layer adhesion is still no good.  They probably have the same colorants as the PETG's.

    It's a shame too as I can get Silky Silver PLA to come out looking "chrome like", but for anything that needs some strength it isn't good.

  • Link to post
    Share on other sites

    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now
     Share

    • Our picks

      • New here? Get ahead with a free onboarding course
        Hi,
         
        Often getting started is the most difficult part of any process. A good start sets you up for success and saves you time and energy that could be spent elsewhere. That is why we have a onboarding course ready for
        Ultimaker S5 Pro Bundle, Ultimaker S5, Ultimaker S3 Ultimaker 2+ Connect.   
        They're ready for you on the Ultimaker Academy platform. All you need to do to gain access is to register your product to gain free access. 
        Ready? Register your product here in just 60 seconds.
          • Like
        • 13 replies
    ×
    ×
    • Create New...