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jpadie
(@jpadie)
Eminent Member
empty layers

hi
Prusa slicer is saying that I have empty layers but I'm not able to see what's causing the artefact.  Anyone with better eyes?

file attached.  intended to be printed with the hollow end on the build plate.  tested with PS 2.1 and 2.2

thanks in advance

justin

 

Posted : 28/03/2020 12:12 pm
Neophyl
(@neophyl)
Illustrious Member
RE: empty layers

no file attached that I can see

Posted : 28/03/2020 12:25 pm
jpadie
(@jpadie)
Eminent Member
Topic starter answered:
RE: empty layers

Frustratingly I have this problem with images on this forum too.  Just doesn't seem to like them!

 

Not sure what to do to remedy that.  

Posted : 28/03/2020 12:30 pm
jpadie
(@jpadie)
Eminent Member
Topic starter answered:
RE: empty layers

second attempt

and third, with a zipped stl.

Attachment removed
This post was modified 5 years ago by jpadie
Posted : 28/03/2020 12:31 pm
Neophyl
(@neophyl)
Illustrious Member
RE: empty layers

yeah you cant post stl files they need to be zipped up.  Best format with issues is to save your project as a .3mf file as that saves not only the model but also all the project settings used too.  What profiles were you using ?

Posted : 28/03/2020 1:30 pm
jpadie
(@jpadie)
Eminent Member
Topic starter answered:
RE: empty layers

Native prusa defined profiles for pla. Tried each from 0.3 to 0.07

Posted : 28/03/2020 1:38 pm
jpadie
(@jpadie)
Eminent Member
Topic starter answered:
RE: empty layers

attached is the 3mf file.

 

Attachment removed
Posted : 28/03/2020 1:56 pm
Neophyl
(@neophyl)
Illustrious Member
RE: empty layers

Theres some strange geometry on the outside near the bottom where it transitions from straight to the bell curve.  Its weird as its manifold so a solid but it like theres a fold back on the edges.   Blender is showing 302 zero faces and 200+ thin faces. So the curve goes down from the top, folds back at the transition so its travelling towards the top again and then goes back down the original direction to the bottom.  It only does this on the outside shell, the interior looks ok.  I think that's whats causing the empty layer issue.  Because its a manifold model and technically correct even netfabb doesn't see it as anything that needs fixing as technically it is a valid model.

I think that when designed an edge loop was pulled down below another.  

Posted : 28/03/2020 2:24 pm
jpadie
(@jpadie)
Eminent Member
Topic starter answered:
RE: empty layers

I designed it in Fusion360.  Happy to share those files ( https://a360.co/2Jim8Tk).  

It's a really simple profile that's then spun 360 to create the bell + an inconsequential holder on the top.  

maybe this is an issue with the STL generator in F360?

Posted : 28/03/2020 2:31 pm
Neophyl
(@neophyl)
Illustrious Member
RE: empty layers

@justin-adie

I fixed the folding geometry in blender and saved it but that didnt help actually.

Also i just noticed that  when placed to bed, the bottom layer isnt touching so its floating.  Thats what slicer is complaining about.  If you use cut and remove 0.2 (possibly less) from the bottom it will then slice.  I think thats the invisibly small parts its having issues with.  

Pure guess here but I think the bottom of the bell is also not exactly 90 degrees which means the bottom thats touching the bed is like an impossibly thin knife edge, so the bottom layer is unprintable due to the extrusion width, and thats why cutting a bit off the bottom makes it thicker.

Posted : 28/03/2020 2:40 pm
jpadie
(@jpadie)
Eminent Member
Topic starter answered:
RE: empty layers

@neophyl

that's really odd.  But thanks - that's sorted it out for me.  The bottom lip had chamfered below 0.4mm (0.3mm) so the 0.4mm nozzle would not have been able accurately to have printed the line.  I guess it would have worked at different orientations.  

many thanks!  Now to try to print it ... 

Posted : 28/03/2020 2:55 pm
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