SOLVED Z banding (?)

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

  1. Henry feldman

    Henry feldman Well-Known Member

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    OK, we're all moving in together?
     
  2. Alex9779

    Alex9779 Moderator
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    First step would be to define a material everyone participating has or can get. I have only Colorfabb and Innofil at home, oh and Taulman Alloy 910... Edge order is in preparation...
     
  3. R Design

    R Design Well-Known Member

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    The lighting is simple: the trick is to light it from above, nearly parallel to the face of the part, to make the layers look as BAD as possible.

    I hold a lamp above my print whilst it is happening so I get a really critical view of what is happening.

    And whilst black hides everything, bright colours distract, white can prevent you from seeing much: light gray is excellent for creating the conditions for study.

    I regularly see very perfect looking prints off Ultimaker printed at a ridiculously low layer height and so judge my efforts against that.
     
  4. Spoon Unit

    Spoon Unit Well-Known Member

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    I have ColorFabb XT grey, which I didn't yet manage to print well and a purple nGen. E3D Everyday PLA (red, white, blue, yellow, silver, black). 3 Edge (Light Grey, Basalt, Racing Green (Krypton on the reel itself :) ) Also E3D Everyday ABS in black.

    We could all benefit here from both printing tuning and photography basics :)
     
  5. Alex9779

    Alex9779 Moderator
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    There are two, "dark grey" and "light grey". I only have "dark grey" both.
    I am inclined to use Colorfabb XT for this, @Henry feldman are you in too? You printed something with XT but I think it is the light grey or white?
     
    #45 Alex9779, May 27, 2016
    Last edited: May 27, 2016
  6. Alex9779

    Alex9779 Moderator
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  7. Henry feldman

    Henry feldman Well-Known Member

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    I have now printed multiple objects in white, which printed really nicely. Still tweaking it back a bit as I am slightly over extruding, but my print last night was super crisp. Have not tried my XT Black

    I am using Wolfbite btw, as at least for me Elmers glue stick was like printing onto greased glass and nothing stuck... Not sure if I need a different glue stick or I didn't say the right incantation (do I put on glue stick after slaughtering the goat or before?).
     
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  8. mike01hu

    mike01hu Well-Known Member

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    Only Edge Grey 45 and PLA silver here but I will be in if either is acceptable.
     
  9. Spoon Unit

    Spoon Unit Well-Known Member

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    Have Grey 45 and 28
     
  10. Spoon Unit

    Spoon Unit Well-Known Member

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    So, to kickstart this little endeavour, I've prepared the following model in OpenSCAD:

    $fn=120;

    wallThickness = 0.97; // don't ask
    diameter = 20;
    height = 40;
    difference() {
    cylinder (r=diameter/2,h=height,center=true);
    cylinder (r=diameter/2-wallThickness,h=height+0.1,center=true);
    }

    This is how it looks in OpenSCAD and S3D respectively:

    openscad_2016-05-30_21-26-14.png Simplify3D_2016-05-30_21-26-29.png

    There being so many settings, I decided to export the whole factory for this, reasoning that even though S3 seems to want to prohibit gcode sharing, the FFF file is only going to be useful to other actual S3D users. I have no idea how many of the settings will be in the file. My intention is to print this with my right hand side, 0.4mm, direct-fed, titan-driven nozzle. I'll go with the Grey28 initially as I believe the lighter material will show this particular issue more strongly than darker materials.

    For photography, I'll use a decent camera. Lighting will be

    1) directly above
    2) shining in at 45% to the camera direction, lighting on the left of the camera

    Neither retraction nor infill should be a factor for the exterior quality as there are only inner and outer perimeters being drawn. I selected optimal start points for print speed which, together with various settings related to retraction should mean there are zero retractions during the main print.

    I'll print initially at 220/70. I won't worry particularly about "elephant's foot" behaviour as it should not be a factor anyway once we get over about layer 5. I've put the fan on at layer 3 at 50% and left it at that for the duration.

    Printed and lit results to follow.
     

    Attached Files:

    #50 Spoon Unit, May 30, 2016
    Last edited: May 30, 2016
  11. Spoon Unit

    Spoon Unit Well-Known Member

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    Very interesting.

    I took the pictures as required, but in addition to taking the picture of the model standing on end, I also took pictures aligning it with the direction of the light when laying down.

    2016-05-30 22.41.34.jpg 2016-05-30 22.42.35.jpg

    2016-05-30 22.44.11.jpg 2016-05-30 22.43.31.jpg

    This is the point where it all becomes so obvious. This is all about minor variation and shadow. The key secret to the photography seems to be to have the light at 90 degrees to the layers.
     
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  12. R Design

    R Design Well-Known Member

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    Good result.

    You don't have an Ultimaker around to run off the same print for comparison?
     
  13. Alex9779

    Alex9779 Moderator
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  14. mike01hu

    mike01hu Well-Known Member

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    Yes Alex, there is a need to consider the variables before people start rushing into results for things that were not being looked for. A standard can only be achieved through agreed dialogue that I thought you were leading. But, we do not want to discourage enthusiasm for the cause.
     

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