Does your 3D prints suffer from the dreaded Problem 66, aka the "Inner Floor Outer Perimeter issue"? Not sure? Then print this quick test object and find out!

This issue causes the outer perimeters, or the outer surface of your prints to have lines or markings along the sides of the print that coincide with having a solid inner floor or inner ceiling in your print. See the .STL model for an example of the inner floor on the top half and the inner ceiling on the bottom half.

We don't know what causes this issue, but here's what we know so far!

Who has this issue:

• It might be a slicing software issue, and not an actual printer problem.
• Most of the people that have this issue are using Slic3r (Prusa Slicer), however Cura and Simplify3D can also be affected.
• Generally, people with this problem who try both Simplify3D and Slic3r, will find that the problem is more visible with prints made on Slic3r.
• Not everyone has this problem.

What affects this issue?

• Printing slower does not seem to fix the problem.
• Printing temperature does not matter.
• This is not a material-specific issue, both PLA and PETG are affected.
• Darker color plastics will make this problem more visible.
• Changing the amount of perimeters does not have any effect.
• Infill density does not have any effect.
• Layer height change does not fix the issue, however the issue is not as visible at smaller layer height settings.
• Turning the print fan off does not fix the issue.
• Printing external perimeters first does not fix it.
• Printing infill before perimeters does not fix it.

Can you help us solve the issue? Can you help us find the "magic bullet" Slic3r setting that will stop this from happening? Be sure to comment, or join the discussion on github:
https://github.com/Photogad/Slic3r-Problem-66

Last Updated: 1/1/2020