Unwanted ridges in print with repeating pattern  

RE: Unwanted ridges in print with repeating pattern

From your description I suspect it's an incarnation of "The Bulge". This is a well-known phenomenon, with more than 20 pages of discussion in this forum.

TL;DR: Many suggestions, no universally applicable solution.

To quote @bobstro:

Happily, this was described as a “buldge” in an early post and that misspelling has made the problem very easy to search for. There are several threads you might want to look through:

• Thread one - Buldge when print reaches solid layers https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-how-do-i-print-this-printing-help/buldge-when-print-reaches-solid-layers/

• Thread two - Any tips to get rid of the bulge? https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-how-do-i-print-this-printing-help/any-tips-to-get-rid-of-the-bulge/

• Thread three - Mitigate wall bulge. https://forum.prusa3d.com/forum/prusaslicer/mitigate-wall-bulge/

RE: Unwanted ridges in print with repeating pattern

Hi fuchsr. Thank you for the links and information. Looks like a common problem with no clear solution :-(. I’ll experiment and post any improvements I find.  Thanks again.

RE: Unwanted ridges in print with repeating pattern

@marka - I've been out of the loop for a bit pending a new job. The latest PrusaSlicer changes to use the Arachne engine should do much to resolve the "buldge" issues. It was a common problem with slicers using printing using fixed extrusion widths, and was particularly problematic on transitions between the internal print characteristics (e.g., from sparse to solid infill, from no to gap infill). Arachne uses variable width extrusions and should help considerably. Unfortunately, life is keeping from playing with it much right now.

RE: Unwanted ridges in print with repeating pattern

Good to hear from Bob! 

From my limited samples so far I don't see Arachne, at least on default settings, as the answer.  But I haven't seriously explored how changing some of the parameters that affect the  algorithm might improve things. 

RE: Unwanted ridges in print with repeating pattern

Bobstro, Fuchsr - Thanks for the replies. My model was printed with 100% fill, so not expecting Arachne in the new alpha release to make a difference. When I get time, I might try Cura to see if it is a slicer or printer issue.

RE: Unwanted ridges in print with repeating pattern

Prusa Slicer Beta 2.5.0 seems to have solved, or at least significantly improved the problem 🙂

RE: Unwanted ridges in print with repeating pattern

instead of 100% infill, try say 200 top layers and 200 bottom layers  (enough top and bottom layers to ensure no infill) and you may get better results

regards Joan

RE: Unwanted ridges in print with repeating pattern

Joan,

Thank you for the suggestion. Would not have thought to try this. I’ll give it a go.

Thanks again

RE: Unwanted ridges in print with repeating pattern

Good luck!

Joan

RE: Unwanted ridges in print with repeating pattern

I've had good luck with objects like this using variable layer height. It will use smaller layers where it is curving more and larger layers where it is more straight. That is something else to try. I haven't tried yet combining Arachne and variable layer height.

Regards,

Mark