Dot gaps in first layer at walls
Hi everyone. I'm having a little frustration with my first layer not quite ever getting fully closed up. At first I battled with very fine lines between extrude rows but I am able to get rid of those with z-axis home offset adjustment.
What I can't seem to quite remedy are the "dots" between extrude rows where they meet the wall (see black square picture, bottom and bottom right corner). I have tried increasing the first layer extrusion width from 0.45 up to 0.52 and that did not help. I have also tried increasing the first layer height from 0.2 up to 0.4 (0.4 is too thick and goopy as expected with 0.4mm nozzle, 0.3 didn't help). I also tried upping the nozzle temperature (240 instead of 230 for 1st layer) thinking it may get the filament to flow more, this also did not help.
The object is a 50mm square that I created in CAD (Fusion 360 I think, if not then Tinker CAD). I extruded it in CAD to 0.2mm height and exported STL. I noticed in Prusa Slicer preview that it looks like you can predict there will be the dots but it's hard to know if that's just the way it illustrates the paths (see screenshot). Could it be the diagonal path that the slicer is using? I know someone in another post used Hilbert infill for some other gap problem.
Any thoughts or is this just as good as it gets? Thank you!
Prusa Mini
0.4mm nozzle (stock)
Prusa textured flexible bed (similar issues with smooth)
Hatchbox PETG (similar issues with COEX PLA and PETG).
Layer height (0.2) (1st and others)
Extrusion width (0.45) (1st and others)
Temps: 230/85 (1st), 240/90 (others)
RE: Dot gaps in first layer at walls
Hi Justin,
did you try increasing the Overlap?
regards Joan
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RE: Dot gaps in first layer at walls
@joantabb
Thanks Joan but that doesn't seem to help. I went to 30% with no change and then 40% make lines appear between every trace.
RE: Dot gaps in first layer at walls
If I switch from rectilinear to concentric solid bottom layer infill I don't have the dots at the edges but I have one small dot in the center of the square where it began printing.
I tried increasing the extrusion multiplier for the filament to 1.05 (from 1.0) and then gaps appeared between traces! I don't get that. I would expect more spread and not less.
RE: Dot gaps in first layer at walls
Have you measured the filament diameter and verified yours is 1.75 mm minimum?
RE: Dot gaps in first layer at walls
@tim-m30
Yep, looks to within +/- 0.01
RE: Dot gaps in first layer at walls
I'd try dropping Live-Z lower (more negative) by 0.02-0.04mm. I see those little holes when I'm right at the edge of being too high. Going a little lower might help close those up without creating a rough surface.
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RE: Dot gaps in first layer at walls
@bobstro
I think this is the fix. I had toyed with going lower before but chickened out when the layer seemed to get the "matte" instead of glossy finish. I have had build plates get scratched by the nozzle in the past too. Just now I went on down to -0.890 in increments and they seem to be gone! It's strange though, the layer thickness doesn't seem to get thinner as measure with the caliper as I go down. It stays around 0.23. Anyway, I think this will work. Thank you!