Hello all, I’ve been using a P1S for a couple of years with Bambu Studio and I’m pretty happy. Today however I’ve found myself in a bit of a pickle.
I designed a very simple button-like thingie for a friend, with a hole from the bottom. When slicing it, however, the hole breaks one of the side walls, even though the original design does have a wall there. This is the object itself:
This is what I get with almost default parameters using the 0.08mm HQ profile for a 0.4mm nozzle:
Enabling “Detect thin walls” doesn’t help much:
The only thing that helped was switching to the Arachne wall generator…:
…and changing the Wall transition length from 100% to 800%:
From the top, it looks like this:
Note that the item is really small — the base is 9.5mm x 9.5mm, the ‘cap’ is 7.5mm x 7.5mm and the hole is 4mm in diameter — so I tried going back to the Classic wall generator and selecting a 0.2mm nozzle, but the problem remains. The hole through the wall is narrower, but it’s still there.
I understand that this is a bit of an extreme issue, and there are limits to what the engine can detect. I made this post in case it may help someone else, and to ask whether it’s something I should officially report to the dev team. I mean, it is a bug in that it shows unintended behavior, but it’s also quite a specific edge case (quite literally!).
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The hole overlaps with the outer walls of the rest of the model…
Using arachne to slice it MIGHT help a little bit but the main issue is the missing material.
The hole itself does not even have a complete wall where it is thin …
I guess the best option if you can’t use different dimensions would be to print the hole about 1mm smaller and to carefully drill it out.
Right, that makes a lot of sense. Unfortunately it’s a very tiny thing, which made taking measurements also a little difficult. I’m going to try and move it slightly on the model, to see if I manage to get the hole fully “inside” — or at least enough to have a reliable thin wall there without resorting to the arachne hack. 
What is the distance between the hole and the wall? I can’t really find that. Or I am seriously overlooking that.
At this time, according to OnShape, it’s just 0.15 mm, which understandably makes it a little impractical to print properly (even setting an outer wall width of 0.3 mm rather than the 0.42 mm default).
I don’t have the actual piece with me, but I’ll try taking more accurate measurements tomorrow and see if I can move it a bit closer to the center, to have at least a wall. The original part is injection molded so it may be less a problem in that case. It’s an interesting learning opportunity for sure.
I would have guessed that Arachne might solve this, but 0.3 is even less than nozzle diameter.
I you really need that tiny wall thickness I would advise you to move the straight wall a bit (0.2mm) over, and remove that from that wall after printing.
Otherwise you can also try to use the part with the open wall. I seems to be out of view.
