Simplify3D: Confusing First Layer settings

First Layer Height and Width:

Simplify3D 4.0 is a powerful 3D mesh slicer program for 3D printing with many options and settings, some of which are non-obvious. Such is the case with the First Layer Settings, under a process' Layer tab. Until I happened upon a post in Simplify3D's forums I didn't understand the effects of changing the First Layer Height and First Layer Width settings, causing me a lot of frustration and failed first layers.

First Layer Height:

Both nozzle height and extrusion amount can be affected by this setting, but perhaps not in the way you think.

If set below 100%:

  • Amount of extruded plastic is UNCHANGED.
  • Layer height (distance from nozzle to printing bed) is REDUCED
  • Values below 100% ONLY lower the nozzle closer to the printing surface. Essentially squishes the standard amount of plastic into a lower layer height.
  • This is meant to help with adhesion.

if set above 100%:

  • Amount of extruded plastic is INCREASED.
  • Layer height is INCREASED.
  • BOTH extrudes more plastic AND pulls the nozzle slightly away from bed so as not to squish the layer.
  • This is used primarily when printing fine layer heights and/or on slightly uneven printing beds. The extra height and plastic volume makes thin layers thicker and also helps smooth out bumps and inconsistencies in bed surfaces.

First Layer Width:

Width changes ALWAYS AFFECT extrusion amounts, but leave Layer Height UNCHANGED.

If set below 100%:

  • The amount of extruded plastic is REDUCED.

If set above 100%:

  • The amount of extruded plastic is INCREASED.

 

For reference, here's the full thread in Simplify3D's forums: https://forum.simplify3d.com/viewtopic.php?f=9&t=2292&start=20#p18419