Hi community, I’m having trouble with some small prints that printed fine before.
I’m printing two-tone 25mm / 1” diameter gaming tokens that have very fine numbers directly onto the build plate. This worked (mostly) fine up until a few days ago. I’d print 10 tokens, and perhaps 1 of those would have a malformed number. Nothing terrible.
Issue:
Since the initial batch that mostly went OK the last couple of tries, most of my tokens have failed numbers on the build plate. I tried several solutions (see below) but it seems like with each try the result just gets worse.
Solutions I tried:
Thoroughly washed the build plate (dish washing soap and hot water)
Reduced Initial layer speed from 60 to 15
No fan on first layer (was already off in settings but still)
Move the prints around on the build plate
Re-tightened screws of nozzle
Maybe superstious: Load filament in other AMS slot (I had it in slot 3 with the fails while it was in slot 4 on earlier prints that didn’t fail so often)
Does anyone have an idea why these started failing?
@MZip@MZip and @TeamPuddlePuppy I will try if drying the filament helps. I did dry it in the AMS2 for 12 hours four days ago, right before I started the first batch that mostly succeeded. Never thought to think to re-dry PLA in such a short time.
I really hope it helps. Unfortunately I’ll have to wait a couple days before I can try it.
That depends on how you store your filament after drying. Ziplock bags leak water vapor in. Put dry air in a ziplock bag and it will be near room humidity in a day or two. They help by slowing down the water infiltration but they don’t stop it.
If you are storing it open to room humidity that’s definitely open to variation and issues if you live in a higher humidity environment.
Smooth PEI plates need to be kept clean or adhesion starts to suffer. Fingerprints are enough to cause issues. I would recommend cleaning the sheet with dish soap and warm water.
I tried arachne in my initial trials to see what would look best on these small letters, but opted for regular walls instead. Those printed fine, until the problem started.
For my initial trials I also tried several surface patterns. Concentric looked good, but I ended up using monotonic line, as I thought it looked best.
The surface pattern is not related to the problem: The first thing printed are the small numbers, and they are just walls, and they already started out malformed.
But I just dried my filament in the AMS2 overnight, and I’m now printing the first layer. It looks like all the numbers have now formed correctly, so hopefully the filament was the issue
Hmm, I didn’t know it could go that fast with PLA. It’s been in the AMS2 for those days, and around 25% humidity (according to the cheap humidity meter I put inside). The room itself has been under 30%.
But I just dried my filament in the AMS2 overnight, and I’m now printing the first layer. It looks like all the numbers have now formed correctly, so hopefully the filament was the issue. Let’s see how it looks when the whole print is finished.
I just dried my filament in the AMS2 overnight, and I’m now printing the first layer. It looks like all the numbers have now formed correctly, so hopefully the filament was the issue. I’ll report back when the whole print finished.
You can force your own color printing order for the entire print or just the first layer. It is accessible through the little nut symbol to the right of the build plate in Studio. In this way, you can force the outer color to print before the numbers. This can also help somewhat.
The way it’s played out here, filament takes a while to absorb much water. When I’ve had to “re-dry” filament, it gets dry much faster than first dry.
I’m not familiar with the AMS2 to know more about how it behaves but have measured the moisture content of filament that starts misbehaving using humidity. For my setup PLA starts having trouble at about a 25% RH reading for moisture content.
As long as the AMS2 doesn’t have desiccant in it, I think your 25% measurement should be somewhat comparable so it’s not surprising to me you were seeing issues.
The way I do the measurement is put the spool in a sealed polyethylene cereal container with a hygrometer and read the humidity when it stops changing (about an hour). You can do the same thing with a gallon ziplock bag but those leak room humidity in and the number will diverge as water leaks in if you let it sit too long.
But I would guess just sitting in an AMS2 that isn’t actively drying should be pretty similar too where RH can be used to gauge how well filament might print.
Also it’s kind of a spectrum. Some models would probably still print fine at 25% RH if they don’t have “more difficult” features.
Thanks for the insight about the moisture. This was the first time I had such drastic failure because of it. It was around 25% humidity where I normally would have between 15 and 20%. But also the first time I printed with an 0.2mm nozzle. Less line width, less adherence to the plate so that probably had something to do with it too.
I’m not sure how well the AMS2 actually dries. I have a bunch of PETG printed containers with dessicant (sillica beads) in them, and adhering to the Bambu Lab pre-programmed drying times (PLA for 12h on 45°C) I just assume it suffices. When not in the AMS2 I keep my filament in vacuum sealed bags. Not perfect, but OK for storage.
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