MK3S Internal Single Extrusion explosion / failure on benchy

[mikewebbatx]

Hi all,

I have been very happy with Simplify 3d so far, and this is my first post on this forum( normally the articles and posts are sufficient) but I could not find anything helpful and I suspect this is an actual bug.

I have been printing/attempting to tune Benchy with PETG today, and I had a major reproducible issue with the chimney.

The Chimney seems to massively over-extrude on the first layer and every layer after that has a single internal perimeter of dark green "internal single extrusion". When I disable the internal single extrusion in process settings -> advanced -> Internal Thin Wall Type to either Gap fill or Perimeters Only the print works fine (albeit, with a hollow chimney)


Left: canceled print, right: gap fill

Am I missing something? This feels to me like it is extruding 2-10x as much as it should. The print slows down massively when it gets to the internal single extrusion and then creates a massive blob, and knocks the benchy off the build plate.

Banchy-6 factory / gcode has the issue (The Single Extrusion options, and perimeter overlap options don't really seem to affect the print very much at all, all massive over extrude.

The Benchy-7 prints fine with gap fill.

I was going to submit the factory files but they appear to be too large for this forum (5mb), and I don't have the patience to deal with that right now.

Thanks,
-Mike

[parallyze]

I was going to submit the factory files but they appear to be too large for this forum (5mb), and I don't have the patience to deal with that right now.

But it is quite hard to have a closer look at the settings in this case... ^^

What I did notice when printing Benchy using S3D:

There's something with the chimney. For example at 0.5mm extrusion width there's 2-3 layers featuring dozens of very short extrusions:

(Internal Thin Wall Type set to perimeter, overlap doesn't have any effect here - 0.4mm works fine, 2 shells)

(albeit, with a hollow chimney)

Depends on extrusion widths/number of perimeters/shells....

creates a massive blob, and knocks the benchy off the build plate.

Does it try to do something like can be seen in the picture above, lots of retracts at some point? If retracting too far this can also cause trouble...

Another note:
According to netfabb the benchy STL is a single shell closed surface, everything looks fine. Nonetheless "Seperate connected surfaces" tries to do so for whatever reason instead of saying it's already a single continuous shell....