Hey all, just got a new H2S and while the experience has been mostly great, I’ve run into a few prints where the quality has been very disappointing.
The issue manifests as irregular wavy or blobby horizontal lines on taller flat parts. It doesn’t show up every time (although I have not attempted re-prints of any of these problem parts yet) but does seem to be linked to tall flat parts.
First part is this model printed in fresh black Bambu PLA. The second part is this model printed in fresh black Bambu ABS.
Haven’t gone out of my way with either the PLA or the ABS to dry it ahead of time since they were recently pulled from the vacuum seal bag with desiccant.
The PLA had been stored in the AMS 2 with desiccants and a ~40% relative humidity for maybe a week after opening. The red PLA from Voxel was probably slightly less well cared for, but approximately similar in environmental exposure.
The ABS had just been pulled from the sealed bag, no drying, but AMS was reporting ~35% RH.
I guess the question is does this look like a “classic wet filament issue” or is it just a data point?
It looks like wet filament to me. In general, filament should never be considered dry even when freshly removed from its shipping packaging. I would not consider 35-40 percent relative humidity dry.
Cool, thanks for the help. I’ll try doing some tests before and after drying.
I haven’t done any 3D print A/B testing before. Any advice? Ideally I’d like to try and print only partials of those parts (e.g. top or bottom half) but I’m wondering if it needs to be at a certain height to really start seeing issues.
The outer loops in the spool may be drier than the inner if initial drying wasn’t long enough. This could be why you are seeing issues further up as the spool uncovers filament with more moisture.
Weighing the spool at the start of drying and drying untill the weight stabilizes has always been my go to method.
Just adding that I had the same issue printing a poop bin. I used an old ABS roll which I did dry a bit before starting the print. I had the spool in a filament dryer and continued drying while printing. But then I turned it off with about 80% of the print to go. In the end, top part had sections which looked like a combination of wet filament and a bit too high temperature (slicer problem).
Thanks for the info! What kind of dryer were you using? I’m considering a couple different standalone dryers (currently between the Creality SpacePi X4 or AMS HT) and am weighing automatic filament swapping (eg the HT) vs drying while printing (SpacePi). I’d sort of prefer the HT for auto switching if it’ll keep things dry enough during the print.
Do you think the HT would get the job done or should I just go with the Pi X4?
Couple of things - 35% in the AMS (assuming the non-drying AMS) is still way higher than I ever let mine get. I suspect the humidity is high enough to actually be adding water to some filaments if it has a lower water content than would cause a 35% RH reading. To each their own but I change out AMS desiccant when the AMS humidity consistently stays at 2 or 20%.
The other point is just general info about new filament - new, sealed filament in bag in box with a desiccant pack can be too wet to print well. All the vacuum bag and desiccant do is extend the time from manufacturing that it may be able to be used without drying.
The problem with that is you don’t know if the filament is still dry. They don’t use indicating desiccant at least that I’ve seen. The vacuum bags are semi-permeable to water and water leaks in over time. How much and how fast depends on the humidity the box/bag is in over the time until you open it to use it. New spools of filament can be anywhere from dry and good to wet and bad.
The Pi X4 is fine, it seals well, and lets humid air out. Temp is OK if your not drying Nylon or PPS every day, I assume.
I have my current setup since Christmas basically, so didn’t have much time with it: I use the X4 on the left hotend, for technical materials (tungsten carbide nozzle for better temps) and the AMS on the right. The missing automatic filament swapping on the left is not that big of a deal I think, because I use that side less often. So the HT seems not like a real benefit to me (has just one spool), and drying while printing is nice to have, especially for longer prints.
About the wet ABS: I agree that no plastic bag is 100% water tight, even the metalized ones. I stored my spool for two years in a vacuum bag with desiccant, and it seems to work.
