SOLVED Z banding (?)

Discussion in 'Calibration, Help, and Troubleshooting' started by Alex9779, May 22, 2016.

  1. mike01hu

    mike01hu Well-Known Member

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    You are correct in the assumption that lubrication prevents sticking but that is in general use with relatively long transitions in either direction, the parameters change for small movements that continuously change direction and stiction will come into effect, hence my reference to auto-levelling. I still hold onto my comments on pillar rigidity and bushing spacing but these will not be periodic unless related to lead-screw eccentricity but this would be worse if the eccentric lead-screw was fixed at the top.

    There are other effects for this type of 3D printing as well of which temperature changes due to PID is one to be considered; this will alter the viscosity of the melt and that will also be periodic and will be reflected in the extrusion.
     
  2. Alex9779

    Alex9779 Moderator
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    Ok here the pictures of the situations I made the two pictures above:
    1) IMG_0611.JPG
    2) IMG_0610.JPG

    So @R Design was on the right track, it is the same cylinders only the lighting situation changed.

    Don't misunderstand me, this was not a test, I wanted serious opinions because as I told earlier I have no contact with other makers and so no comparison.

    The assumption of @R Design it could be speed related was also a good hint, I tried my Apple Pencil Case and had a similar effect and exported it again from SolidWorks with a higher resolution. And I printed it with less speed, 0.1mm layer height and the result is WOW:
    IMG_0010.png IMG_0011.png
    Again two shot with the different light...
    Also I found that for this part nGen does not like cooling fans, the best result I had was with no fans!
     
    #22 Alex9779, May 25, 2016
    Last edited: May 25, 2016
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  3. Alex9779

    Alex9779 Moderator
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    Oh just for reference, the Apple Pencil Case was printed with my S3D profile with a slightly (just removed the forced retraction on layer change) Fine/Slow quality setting and the nGen settings...
     
  4. mike01hu

    mike01hu Well-Known Member

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    Interesting bit of research Alex :rolleyes: and I have a lot of respect for @R Design 's observations that I also take note of, even though I have been printing for several years. What you have achieved with the model is excellent provided it is repeatable, something that we all strive for in our dreams. R Design's comment inferring just using the printer to do the job and not worry too much about fine quality is OK by me, as most of my products are hidden from everyday view and it's the job they do that is more important. Your Pencil Case has to have an aesthetic appeal too, so requires repeatable high quality and the outcomes are important to the rest of the community.:)
     
  5. Alex9779

    Alex9779 Moderator
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    On the way to here I had parts that looked nice but had lines along the outside where it seems the part shrank (had to look up in the dictionary, "shrank" sounded so strange :p) a bit more.
    I found that the shrank line were exact where the bottoms of the inner holes started. Because the bottoms are not all on the same level I had several shrank lines on the outside.
    Then I thought about why that is and tried printing without cooling, because I thought they shrank a bit more than the others because there has been more time for them too cool down because of the additional full infill which had to printed at those levels...
     
  6. Alex9779

    Alex9779 Moderator
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    Here is a new shot:
    IMG_0013.png
     
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  7. R Design

    R Design Well-Known Member

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    Nice work.

    If I had an Apple Pencil I probably wouldn't have time for a Solidworks Analysis of air flow under an X carriage either! ;-)

    EDIT: just seen you've actually done it and it's giving totally amazing information...
     
    #27 R Design, May 25, 2016
    Last edited: May 25, 2016
  8. mike01hu

    mike01hu Well-Known Member

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    I would buy those but I'm not an Apple fan;)
    It is a great advantage being a SolidWorks reseller as you get all the training and the best versions. I'm jealous! :(
     
  9. Alex9779

    Alex9779 Moderator
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    ROFL, I had never a training, when I started 1 month later I had to do a training as a trainer for EPDM.
    I am responsible for the data management, SolidWorks itself is not my main business nor the addons like simulation or flow. I got all the licenses so because data management has to deal with them all...
    And "best versions" is an euphemism... I have to have most of the time the newest and to be honest the newest is not the best and IMHO SW is getting worse since a few years. Features, features and more features is the way they go. Things which do not work reliable or not at all for YEARS aren't fixed...
     
  10. mike01hu

    mike01hu Well-Known Member

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    I was joking:p! My early days in CAD were being given a version of AutoCAD by them, the first on a 8086 based system, then asked to train the trainers with no training myself! All part of the fun:cool:
     
    #30 mike01hu, May 26, 2016
    Last edited: May 26, 2016
  11. Chase.Wichert

    Chase.Wichert Well-Known Member

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    You know I saw something a long time ago where they would put a small bearing under the lead screw inside the coupling... I am not that experienced to diagnose this though. I would tell them to only look at it in low light situations.

    Oh, the company I work for has a several hundred thousand dollar printer and it looks like that.
     
  12. Alex9779

    Alex9779 Moderator
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    Cool that is a nice comparison :D
     
  13. Spoon Unit

    Spoon Unit Well-Known Member

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    Amazing that simply moving the light has such a big impact on the appearance of external lines.
     
  14. Alex9779

    Alex9779 Moderator
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    Ya and see you now what my problem is when watching photos of print of other people?
     
  15. PsyVision

    PsyVision Moderator
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    Remember all of my rocket prints when I first got my BB?

    Filament colour, lighting, print settings and (of course) mechanical issues can all contribute.

    My observation is that the black object looks okay in both photos, the white is okay in the first but the second allows you to see what I would call a fairly even banding.
     
  16. Spoon Unit

    Spoon Unit Well-Known Member

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    Ideally, we should all print the same item with the same material using the same settings and then photograph under similar lighting conditions. This should limit differences to lighting and machine setup.
     
  17. Alex9779

    Alex9779 Moderator
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    Oh and just thought that I am at the top of quality and don't even know it?
     
  18. Alex9779

    Alex9779 Moderator
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    Ideally we should... You know yourself how many factors can influence the quality and the outcome. And the presentation is one too. Compare our pictures to them Colorfabb or E3D posts on their filament marketing sites. Those parts look perfect. I think you would be surprised if you'd see them in reality... Just like super models...
     
  19. Spoon Unit

    Spoon Unit Well-Known Member

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    Haha. You think they've been photoshopping too ... ?
     
  20. Alex9779

    Alex9779 Moderator
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    No idea. The base at the clear Edge filament shows some imperfections but transparent stuff is hard to light to hide that...
    But you see what I can do just by moving my wirk light around. A pro photographer has more possibilities without using Photoshop... And the you can gently just smooth the pic... Small changes have a huge effect you don't have to rework the whole pic...

    But for me this thread is turning out good. I know now that I have pretty good quality and can take a step back on trying to improve it...
     

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