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Unresolved Defects on print surface.

Discussion in 'Troubleshooting' started by Oisin, May 23, 2017.

  1. Oisin

    Oisin Member

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    Hi guys. I'm having some strange little pellets be deposited on my print as per my images. I'm wondering if anyone could help identify it. I'm using a Robo3D R1 and the slicer is Simplify3D. Printing at 40mm/s, 0.1mm layer height and my retraction settings are 3.6mm at 100mm/s. Extrusion multiplier is 98%, and my extruder is calibrated correctly as per Toms guide. I'm using Woodfill PLA at 195C.

    I have used the visual guide Mike posted in an attempt to identify what is happening but it's stumping me a little as the only similar thing in the images is the stringing, but I've already played with the retraction settings. The defects not a huge deal to remove, but it would be nice to get clean prints and not have little imperfections on the surface.

    Could it be a nozzle issue? It's as if it's extruding slightly more than it's laying down and the excess is slowly building up on the nozzle and getting deposited periodically. Could it be something to do with the stringing?
     

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  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Did you check the nozzle diameter?
    I imagine not, most don't have a pin gauge that size handy :)
    You can check the extruded filament diameter (which will not be the same as the nozzle size, but close).

    Stringing with PLA/ABS is usually a sign of too much extrusion temp, I know ... 195C seems low by the specs, but I have one printer where 185C is the sweet spot for PLA. You really need to test it to perfect it.

    Lastly, sometimes... it is just the filament. Do you get the same artifacts with another spool? If that really is ColorFabb Woodfill and switching (as a test) to another spool sorts or helps it... then contact them they may just replace it.
     
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  3. Geof

    Geof Volunteer Moderator
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    woodfill in my experience is stringy anyway. Up the retraction, drop the heat, up the speed (if you dont decrease temp). Most times when you run your finger across those strings it will clean up. I do more woodfill then I'd like to admit on my Gmax. If using S3D you can also cheat (I do this alot) and up the "do not cross perimeter" to 300 mm or higher if it will let you so it doesn't cross to string.
     
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  4. Oisin

    Oisin Member

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    The nozzle diameter 0.25mm, or it was when I bought it. It has probably seen less than 200 hours of printing. I feel like that's not a lot. I'll see if I can find my calipers to check the extruded filament diameter.

    I'll try lowering the temperature. I just didn't want to cause the hobbled bolt to grind if I lowered the temperature too much. I got the exact same artifacts on the same print with my spool of PETG with completely different settings, making this a little weirder.

    My settings for PETG are: Retraction 1.5mm at 100mm/s. Layer height 0.1mm. Print speed 40mm/s and temperature 235C.

    The Woodfill I am using is quite an old spool. It'd be worth ordering a new one.
     
  5. Oisin

    Oisin Member

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    I'll definitely try your suggestions once this print finishes. I'll print a second one with your settings to compare. I love the surface finish on woodfill prints, so it'd be nice to clear this up. Thanks Geof.
     
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  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Retraction is dependent on a lot of things. Mine is twice that one one printer (not a Robo).
    0.25 mm nozzle means about half the print speed normally (so I expect you have already tuned that in).

    It could simply be a bum spool, they do happen although it is far more rare from the brand-names.
     
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  7. Oisin

    Oisin Member

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    The below images are of the print after changing retraction from 3.6 to 6mm, temperature from 195C to 180C and that's all. Speed was 40mm/s and layer height was 0.1mm

    I tried another one with the coast at 0.50mm but it made no difference.

    However, you can see that the back part of the blade in the second image is absolutely flawless. Not one issue. That's how I'd like the whole fan to look eventually.
     

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  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    To my eye the first one still looks better than the prints you had posted previously...
     
  9. KTMDirtFace

    KTMDirtFace Well-Known Member

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    I got those boogers with colorfabb XT.. i never could figure it out. chalked it up to the filament
     
  10. Oisin

    Oisin Member

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    It's an improvement but still something that shouldn't be occurring. I've yet to try some fresh filament so we'll see what difference that makes, if any.
     
  11. Oisin

    Oisin Member

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    And it doesn't occur with other filaments? Because the exact same thing happens to me with PETG, so I was thinking it was a printer thing.
     
  12. KTMDirtFace

    KTMDirtFace Well-Known Member

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    What about regular PLA?

    Maybe its a setting I dont really know. But I never got those little balls on anything except one filament.
     
  13. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  14. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    All of those are retraction related. Too little, too much, not done at the right time, etc.
     
  15. Oisin

    Oisin Member

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    I've not had any regular PLA, KMT. I've only run PETG and the Woodfill through it and had the same effect with both despite pretty different settings.

    I mentioned in my original post that I had a look at the Troubleshooting guides Mike posted and that was the very article I looked at, Mark. It was pretty useful

    What I've done is attached screenshots of my settings. Maybe there's something obviously wrong there in terms of the retraction settings or anything else.
     

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  16. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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