What is causing this???

[Silverback]

Short version (I'll add more details for those that want to read them later):

I've done some of the built-in tuning (what I could figure out so far, I have a thread about that: viewtopic.php?f=11&t=2906&p=7793#p7793) and I've gotten a bunch of next to perfect prints, but I have one larger print that I just can't get. 3 sides, plus the top/bottom and inside surfaces are either very good or perfect, I'm very happy with them, and one detail on one side is doing this:




Here, a shot from the top, you can see that the wall is actually thinner in that spot, those are the outside layers of the wall not sticking to the part:


What is causing that/how do you fix it?

[Silverback]

So, some details:

This part is 1/4 of larger part, if you printed a second one, turned it 90* the long flat ends on one will fit in the little pockets on the other lining parts up and everything interlocking for gluing.
Printed using Inland PLA+ at 220/60*c on a modified Anet A8,
.4mm nozzle, .4mm extrusion width,
Layer Thickness .28mm - 100%,
2.5 loops printed perimeter first (the little pockets on one side are supposed to fit the ends of the other side giving me an interlocking glue joint so I was worried about outside dimensions and there are no overhangs, I figured outside to inside is safe here).
Seam depth 1.0, jitter 0, seam gap 0.0, Corners checked, join-loop set to seam and seam angle to the same corner that the problem is in.
Printed somewhat fast (but I've printed faster without problems):

• P 30
  L 60
  S 50
  S 60

[pjr]

That looks very much like preload being too high

Unload the model and I will attempt a print.

Peter

[sinned6915]

the material is probably fine, i use that filament too.

i would model a little part with those thin features and tweak before i printed a full sized part.

'thin' features take a bit of fiddling to get right. and by thin, I mean those that are 2-3 extrusions total in width. your crown setting comes into play here too. think about how the perimeters and infill interact. if your part is 1.0mm thick and you have 2.5 loops, its a mathematical nightmare as the loops and perimeters start overlapping each other.

you might want to tweak the extrusion width widths thinner to like 0.34 to 0.38, or even go fatter all the way up to 0.6, but if you go FAT, go THINNER on your layer heights.

maybe try perimeter 1st and 1 loop, or 2 loops. infill might also make things harder. you can try in infill of 0 and increase loop.
play with the settings and look at the previews and print times.

what are your preload and destring values at? their velocities? if you are direct drive, you might try a preload of 0.

why the 0.28mm layer thickness?
what are yhr P, D, S & S values you are giving? Are those speeds?

try slicing it and use the sliders to see where the loops start & stop, changing by layer. change parameters and take notes as to what your observe.

then print only 5-10 layers of the next one to see what is going on.


some suggestions-
seam depth 0.1
seam gap 0.6 - 0.8

jitter:
360 and set to corners and it will bury the seam at random corners. though i wonder if the small tenons and dadoes might be making things difficult.
or make them all at the corner to the left from the slot/tenon feature.

layer thickness- are you setting by number or by fraction? you can hardcode it or give it in terms of %
so for 0.4mm extrusion witdh, you can use 50% min layer, 75%max layer and first layer of 75%
or
0.2mm min layer, 0.3mm max layer, 0.3mm 1st layer.

stepover- i like % for this and use 50% for both.