Use this configurable (parametric) calibration ruler for both ghosting
and steps/mm calibration, depending on how it is configured in
settings.txt.

Find out what else is available and how we can help each other: zahyest.com

How to Use

(Print one of the STL files if applicable and skip the remaining steps,
otherwise continue.)

• Open ConfigurableCalibrationRuler.scad in OpenSCAD
• Edit settings.txt in a text editor as desired (see example(s)).
  • Set enable...ruler values to true if you want marks and
    numbers along the bars, or to false if not (the bar will still be
    present).
  • Set a bar length to 0 to remove the bar.
  • You can set the length, width, and thickness of bars.
  • Set constant_hole_size to 0 to get all sizes (10mm to 1mm, or to
    whatever will fit if your zbl [z bar length] is much below 90)
    or set a size.
  • After you change a setting then press save in your editor, OpenSCAD
    should update the preview automatically.
  • "//" begins a comment in scad format that OpenSCAD will ignore.
• F6 (shortcut for Design, Render). Wait for the model to appear.
• File, Export, choose a format (such as STL), and name it as desired.
• Slice and 3D print the file you exported.
• Measure the axis (see "How to Measure"), then set your 3D printer's
  steps per mm by multiplying the current steps/mm by the error
  correction ratio (size in settings divided by size you measured).
  • If there is not a precise result: Still set the steps/mm, but then
    print again, and set Slic3r's scaling values to the new error
    correction ratio.
• You can calibrate the steps/mm for your extruder motor separately,
  without the calibration ruler:
  https://3daddict.com/3d-printer-extruder-calibration-steps/
• Ghosting can have many causes. You can detect ghosting using this
  calibration ruler, but I do not provide steps and don't know all
  potential steps that are necessary to correct ghosting.
  • Do a web search for the term "ghosting" along with your printer's
    brand and model number.
  • One possible cause is gear backlash. See Quick Backlash Calibration
    V.2
    by Muele Mar 4, 2017.

How to Measure

• Always measure to the end of the ruler (or if you want a different
  value than settings, measure to the near side of a line on the
  ruler).
• When comparing the measured width (not thickness) of one of the bars
  on the Z axis, the expected value is the thickness of the other bar
  plus the width of the bar you measured.
• For the X axis, measure from the near face of the Z's Y-axis bar.
  • The X-axis bar is now on the inside, to make measuring more
    accurate and make it more adaptable (always connect with model,
    and avoid boolean artifacts) in case of changes to the Y-axis
    bar's length or width.
• For the Y axis, measure from the beginning of the ruler.
• For the Z axis, measure from the beginning of the ruler (the bed).

Authors and Licenses

• Write.scad (and dxf font models):
  by HarlanDMii.
  • License: See "LICENSE for Write.scad (and dxf files).md" or https://www.thingiverse.com/thing:16193
• Everything else: by poikilos
  and RichieC.
  • License: http://creativecommons.org/licenses/by-sa/3.0/

Requirements

• (now included) Write.scad
  by HarlanDMii
  Jan 18, 2012
  • requires "openscad version 2011.12 or later"