I have a 220 mm tall, fairly narrow part that looks clean for the first two thirds, then the walls start showing obvious ringing/ghosting near the top.
The same printer/settings produce clean shorter parts. Belts feel properly tensioned, the frame is tight, and the first 140 mm of this exact print look normal. That makes me suspect the part itself is flexing more as it gets taller rather than the machine suddenly developing a mechanical problem at one height.
Current setup is PLA, 0.4 mm nozzle, 0.2 mm layers. Outer walls are around 45 mm/s and acceleration is not especially aggressive, but the geometry has several direction changes near the top. If I gently push the finished part, it is easy to see how much more leverage there is at 200 mm than at 50 mm.
I can think of a few ways to attack it:
- slow outer walls and reduce acceleration for upper layers,
- change orientation so the narrow axis is better supported,
- add a temporary brace/tower connected with small breakaway tabs,
- print two copies at once so each layer has more cooling time (though I doubt cooling is the main issue).
I would rather not slow the entire print if only the tall section needs it.
Does this sound like part wobble, and if so, which change usually gives the biggest improvement before redesigning the whole part?
I can also modify the model if that is the honest answer. A removable brace would be easy to add and this is a functional part, so I care more about dimensional stability than saving a few grams of filament. I am mainly trying to separate printer tuning from geometry that is inherently too flexible.
4 replies
That does sound like part flex, yes. If the bottom is fine and the top starts ringing when the part gets whippier, the model itself is proba...
That does sound like part flex, yes. If the bottom is fine and the top starts ringing when the part gets whippier, the model itself is probably contributing.
I’d try lowering acceleration just for that print before redesigning it. If the machine is already okay on shorter parts, the extra motion at the top may just be exciting the skinny section.
Agreed, but I would still test orientation if you can. Sometimes the fastest fix is just making the narrow axis less annoying to print.
A temporary brace is not overkill if the part can tolerate it. I’ve had tall prints clean up a lot just from giving the top something less floppy to work against.
The good news is your diagnosis is already pretty close. If shorter parts are clean, I’d separate “printer problem” from “tall skinny part p...