Is this a sign of damp filament?
I’m trying to print drink coaster tops with Fillamentum PLA Extrafill Crystal Clear Iceland Blue, and I keep having an issue about 15 minutes in to the print. The filament keeps getting boogered at the nozzle, see picture, and stops coming out of the nozzle. (I removed the PTFE tube at the print head to get a picture.)
I am able to push a random piece of filament through the print head by hand with the tube removed. And after removing the PTFE tube I was able to advance the filament with the open tube with the purge option on the Mini’s control panel. There was a small gouge in the filament from the extruder, see photo but I don’t think it’s a tension screw issue.
The rest of the filament looked fine to me.
Yesterday I completed a print with this material, but now this has happened 3 times in a row, and at about the same point in the print. I’m running a test print now with a completely different material (PolyLite PLA Pro) and the print looks beautiful.
Is this a sign of damp filament? If it is, wouldn’t my run yesterday have done this? Why would it happen with material “deeper in the spool”? Having used this material previously I do know it is brittle. I have it in my dryer now, but is there anything else I need to consider? Thanks!
Mini+MK3S+XL 5 Tool
RE: Is this a sign of damp filament?
Update, I placed it in my dryer overnight and it did not help. Tightened and loosened the tensioner screw, adjusted the live Z and I still get breakage at the extruder about 10 minutes in to the print. I’m using the material just fine on my MK3S+, but unfortunately I need to have that machine printing something else.
Mini+MK3S+XL 5 Tool
RE: Is this a sign of damp filament?
I do not have the Mini, but I've seen this effect, or one very similar, on an Ultimaker when the print head fan fails or is obstructed. This causes the filament to start melting before it should and clogging.
RE: Is this a sign of damp filament?
While it doesn’t appear there is an obstruction, what you described seems like what is happening. I’ll take a second look in that area. Thanks.
Mini+MK3S+XL 5 Tool
RE:
I found a photo of what I was talking about.
The Ultimaker hot end has a metal tube above the hot end.
Notice the 'swelling' of the filament except for maybe 4mm just distal to the Bowden tube. The filament was melting before it was supposed to and the feeder was pushing the solid filament into a long pool of constrained molten filament in the tube and the extrusion was weak and erratic causing a print with very poor strength and an obviously defective appearance.
This one even stumped the first-line Ultimaker tech support folks, until one veteran reported that he had seen it before. Cleaning (and eventually replacing) the print head fan fixed it.
RE: Is this a sign of damp filament?
Haven't had a chance to take a look, yet (kids are playing hockey all weekend). I know there is some dust around the heatsink, that may be just enough to cause the thermal issue you are describing. It worked great with the other PLA, but that crystal stuff can be a little bit fussy.
Mini+MK3S+XL 5 Tool
RE: Is this a sign of damp filament?
I finally had a chance to clear the fine layer of dust from the heatsink, and the fine folks at Fillamentum Reached out to me and suggested I use 230º as the print temperature for this material. I don’t want to jinx myself but those seemed to have addressed the problem. So far so good, and I’m back to printing coaster covers. 😁
Mini+MK3S+XL 5 Tool
RE: Is this a sign of damp filament?
Five sets in to it now and thankfully the issue appears to have fixed itself. Was it the dust? Was it the temperature change? Probably a little bit of both. I usually try one “fix” at a time to know for sure, however I was tired of removing the PTFE tube to clear the stuck filament, and needed to get back to printing.
Thank you @jsw for your help.
Mini+MK3S+XL 5 Tool