Why slicer presets are only starting points
TL;DR presets are fine for toys and trinkets. Proper calibration is what makes functional parts fit.
I’ve posted about this before, but it keeps coming up, so I’m repeating it to emphasize the point.
So this really applies to functional prints. If you’re printing decorative stuff, fidget toys, desk trinkets, or anything where fit and strength don’t really matter, presets are generally fine.
For functional parts, though, slicer presets are a useful starting point only.
They are not proper calibration and they are definitely not tuned for your printer. They are just a set of reasonable defaults meant to work well enough on a lot of different configurations. They assume things like: dry filament, a certain types of nozzles, average thermal behavior, safe flow limits, and generic dimensions.
I get asked pretty often to share my settings for a specific filament. I get it, but it is usually not that helpful for functional prints. Those settings only really make sense on my printer, with my nozzle, in my environment, and with whatever moisture state that filament happened to be in. Copying them to a different setup often gives mixed results, even with the same brand and color of filament.
As soon as anything changes, different filament, different color, different nozzle material, a high flow nozzle, or even just drying the filament after you have already printed with it, the preset or copied profile stops matching reality.
That is why functional parts so often almost fit after a long print and wasted filament.
Calibration is replacing assumptions with measurements. It is how you deal with the stuff presets cannot assume, like how dry the filament actually is, what temperature really works with your nozzle, how much plastic you can push, how your corners behave, and how much the material shrinks.
Presets and shared profiles are a fine place to start. They are just not where you should stop if fit and reliability matter to you.
I'm assembling an article on Printables that explains my calibration process. Will link it here when I'm done.
RE: Why slicer presets are only starting points
Would add here that if you are primary printing PLA/PETG and stuff you've downloaded from Printables you can generally ignore this advice. It applies when using engineering filaments and accuracy is key.