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konstantin.a
(@konstantin-a)
New Member
Improving seams?

Hi all,

I'm trying to tune my i3 Mk2 and currently I'm looking into why the seams in my prints are so pronounced. Here is a list of things I adjusted:

  • Firmware v3.1.0

  • Bed leveling and first layer height

  • Extrusion multiplier (by printing a single perimeter vase)

  • Linear advance K factor (using http://marlinfw.org/tools/lin_advance/k-factor.html )
  • To test the seams I print a cube with 3 perimeters (inner first), no infill and random seam locations. This is what it looks like (looking at a couple of layers of a cube from the outside):

    I stopped the print in the middle and this is what a completed layer looks like under magnification:

    Here is what a layer with incomplete outer perimeter looks like:

    Is there something I can do about it? In particular, why is the transition between perimeters is so diagonal (almost 45 degrees)? Looks like this is why a seam is so pronounced. The g-code looks normal - transition between perimeters is perpendicular to perimeters themselves:

    I know that I can try to hide the seams, but I wonder if I can make them less pronounced to begin with.

    Posted : 16/01/2019 6:10 am
    bobstro
    (@bobstro)
    Illustrious Member
    Re: Improving seams?

    You can try to calibrate your extrusion multiplier to avoid bulging. Seams are always going to be there, and the easiest fix is to hide them in a corner. Slic3r only offers basic aligned or closest options which will tuck seams into a corner if possible. Random sound great, but always seems to leave that "zit" appearance which is worse IMO. Cura offers a lot of additional options for hiding seams.

    By far, the slicer with the most effective, yet frustrating to use, features for dealing with seams is KISSlicer. It offers some really interesting "fuzzing" that keeps seams near each other, but spread over a user-selectable area. This, together with some fanatical tuning features, may allow you to reduce the seam appearance to levels that are acceptable to you. The KISSlicer documentation is a good read on the issue if nothing else. Michael Hackney has a great set of videos on YouTube that do a good job of explaining the issues, and how KISSlicer can be used to mitigate (but not eliminate) them.

    Unfortunately, on a cylindrical shape with no corners, they still appear somewhere. If you really need a smooth shape and appearance, sanding and finishing may be your best options.

    My notes and disclaimers on 3D printing

    and miscellaneous other tech projects
    He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

    Posted : 16/01/2019 1:09 pm
    konstantin.a
    (@konstantin-a)
    New Member
    Topic starter answered:
    Re: Improving seams?

    Thanks.

    However, I don't think the problem is buldging? The seams are missing material it looks like. It seems to me that the extruder path is different from what the gcode prescribes - it "rounds" the corner (on the third picture). Am I looking at it wrong?

    Posted : 17/01/2019 12:49 am
    bobstro
    (@bobstro)
    Illustrious Member
    Re: Improving seams?


    However, I don't think the problem is buldging? The seams are missing material it looks like. It seems to me that the extruder path is different from what the gcode prescribes - it "rounds" the corner (on the third picture). Am I looking at it wrong?

    Let me back up. Your prints look pretty good and show typical layer seams as they appear when you select the Random placement option. You can play with the other placement options in Slic3rPE to see if it's possible to hide them in corners. You can try printing external perimeters 1st. I'm unaware of any other pathing options in Slic3rPE and I've spent a fair amount of time with it. You can try more complex options with other slicers. KISSlicer has options for tuning exactly the sorts of pathing you're discussing. Unfortunately, you cannot get rid of layer seams completely with the current state of FDM 3D printing consumer technology.

    I only meant to note that calibrating your material can help with layer seams in some cases. Yours look pretty clean so I wouldn't expect any improvement.

    You might enjoy Michael Hackney's YouTube videos on KISSlicer. While he focuses on that slicer, he spends a lot of time on slicer paths and different implementations.

    My notes and disclaimers on 3D printing

    and miscellaneous other tech projects
    He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

    Posted : 17/01/2019 1:27 am
    konstantin.a
    (@konstantin-a)
    New Member
    Topic starter answered:
    Re: Improving seams?

    Thanks!

    I finally had time to tinker a bit more. I switched to KISSlicer - the seams look much better. I like the KISSlicer more so far.

    Posted : 27/01/2019 6:30 am
    Nikolai
    (@nikolai)
    Noble Member
    Re: Improving seams?


    I finally had time to tinker a bit more. I switched to KISSlicer - the seams look much better. I like the KISSlicer more so far.

    Would you mind post some pics of the KISSlicer printed models, magnified the same way? What is it doing different? I know every slicer is handling it slightly different.

    Often linked posts:
    Going small with MMU2
    Real Multi Material
    My prints on Instagram

    Posted : 27/01/2019 6:59 am
    PJR
     PJR
    (@pjr)
    Antient Member Moderator
    Re: Improving seams?


    What is it doing different?

    The Perimeter path starts and ends on the inner loop with movement to/from the perimeter in a constant extrusion. The width and depth of the gap can also be specified.

    Peter

    Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

    Posted : 27/01/2019 11:06 am
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