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Rough looking overhangs  

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Omnissiah
(@omnissiah)
Eminent Member
Rough looking overhangs

Hello,

I have a Mk3 working quite well, apart from the occasional werid inconsistency.

In this case, overhangs look quite rough, and not nicely layer-y. See the bottom piece on this picture:

This is a 45° overhang, at 0.1mm layer height with default Slic3r print settings. The overhang looks fine when I print 0.2mm layers. This is using Prusa PLA, and the default Slic3r settings for it, on a 0.4mm nozzle.

Interestingly, when I rotate the piece 180° around the Z axis (so the overhang faces towards me instead of away from me), I get nice looking overhangs, as seen in the top piece of the picture.

I rule out X-axis problems, due to the fact that it looks ok when rotated 180°. I've tried reduing flow from Prusa's default 95% to 85% to no avail. At this point I can only suspect slicer shenanigans...

What's going on? Thanks!

Publié : 25/12/2018 10:10 pm
thrawn86
(@thrawn86)
Honorable Member
Re: Rough looking overhangs

which direction was it oriented on the bed? might try facing the overhang towards the front if it wasn't already. it looks like the seam is on the left corner, you might also try moving it.

Publié : 25/12/2018 10:45 pm
Omnissiah
(@omnissiah)
Eminent Member
Topic starter answered:
Re: Rough looking overhangs

Thanks, curtis. The overhang is facing away from me. If it have it face me instead, it looks much better, as explaiend in the start post.

Do you think Slic3r generates different perimeters seams depending on orientation? This could indeed be a reason. However, I'd like to get smooth overhangs, no matter if there are seams near or not. That's what I'd like to fix.

Publié : 26/12/2018 2:34 pm
thrawn86
(@thrawn86)
Honorable Member
Re: Rough looking overhangs

sorry I didn't see you mentioned that already.

the fact is that the printer is subjected to all kinds of acceleration and resonances and thats why the beginning and end of a single extrusion can look different sometimes. The beginning and end of an extrusion is when this will be the most apparent, and if the seam is on an overhang then there isn't much way around it.

slic3r only gives you the option of random/nearest/rear/aligned for seam position, so you'll have to watch your gcode preview carefully and see where it lands. other slicers let you specify a point to align them with.

Publié : 27/12/2018 3:49 am
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