I roughly eyeballed and drew up a similar part in CAD to try printing in some different orientations.
I attempted 3 different orientations, all supported with Supports V2, with Tough 1500 V2 on Form 4 @ 100µm.
- Thread-side directly down
- Thread-side directly up
- Thread-side down, tilted 5º
In all cases, I auto-generated supports with Supports V2, then used Manual Edit to remove supports placed on the threads, since threads are generally somewhat self-supporting (depending on the pitch/size, but we will ignore in this example.)
From a technical perspective, @Friedl_1977 is right that angling a part generally improves surface quality by reducing sudden peel force changes. But in this case, since the threads are the most important feature (they are mating faces that have to fit properly), I would actually recommend printing the part flat/parallel instead of angled. Even if angling improves the general surfaces, it can cause more drastic overhangs on some of the threads, leading to distortion on one side. For me, it’d be better to have consistent, even threads all the way around—perhaps imperfect but uniform—than threads that bias in specific spots.
Here are the three parts:
As expected, the ones printed flat on supports (leftmost & rightmost) have really bad undersides from the support interface (the reason we don’t recommend printing flat surfaces parallel to the build platform on supports), but the threads came out the cleanest and most uniform.
Even with just a 5º tilt, I noticed the threads started to become inconsistent and thicker in certain directions. That tradeoff (to me) isn’t worth it if the threads need to function properly.
Unfortunately, this is one of those cases where the part just wasn’t designed/optimized for 3D printing, and you have to weigh the tradeoffs of different printing orientations. If you want clean surfaces and clean threads, my personal solution would be to split the part. Plane cut around the lip like this, print both halves flat on the build platform (add drain hole(s)), and glue/epoxy them together after post-processing. That way, both sides get clean surfaces (since areas of interest would all be facing upwards), you won’t need supports at all, and the threads stay uniform all around. You could even add slight locating geometries (keys) if you want to align them easier when glueing (not pictured).
Hope this makes sense (and helps)!
In fact, for thin, flat and tall parts (eg. base of an enclosure) the best for me is to print perpendicular to the build plate.
