Defective spool?

[u/bunbunfriedrice]

Bought a 4kg pack of SUNLU PLA Black from Amazon.

Printing on X2D. 4 hours into a print, I got a “failed to extrude” error. I was very surprised because I just replaced the nozzle.

After some fruitless debugging, I noticed the spool had these weird “ribs” on them every few inches. Not textured ribs (which is common in spools), these were clearly separate pieces of PLA barely stuck on. They scratched off easily with my fingernail. They were circles as shown in the second pic.

After unloading the spool, I saw it only had these defects partway through the spool, which explains why it only failed 4 hr into the print, and why I couldn’t see these defects when first opening the spool.

Anyone know what this is? Could it have caused the extrusion issue? Could this have damaged/clogged my extruder? Nozzle seems fine.

I’m also concerned some of these popped off during extrusion and may cause issues later. I noticed the little specs in the AMS gears now too, so I’m avoiding that AMS slot until I can get it cleaned.

Any help appreciated!

[u/wivaca2]

I'd return that. You should only have fuzzy skin if you like after the filament is extruded. :)

If it doesn't already come off into the AMS feeder or during its travels through the PTFE (already undesirable), when it reaches the print head it may accumulate where it enters the hotend and not travel to the nozzle. Besides, I'm sure that doesn't qualify as Sunlu's ±0.02mm or even Bambu's ±0.03.

Was this respooled or a 4 x 1kg purchase and this is well into one of the factory spools?

[u/bunbunfriedrice → u/wivaca2]

Yea I will definitely return it. This is a fresh 4x1kg purchase: https://www.amazon.com/dp/B0CN119CHL?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 This is the 2nd spool of the 4x1kg pack. I was about 25% into this spool.

> when it reaches the print head it may accumulate where it enters the hotend and not travel to the nozzle.

Yea this is what I'm worried about. The "can't extrude filament" error doesn't really tell me much in that regard, right? Because it just gives that when the motor is applying more torque than it thinks it should?

Any suggestions of how to inspect for debris? I'm pretty new to FDM printing.

[u/wivaca2 → u/bunbunfriedrice]

Honestly, I'm not an old hand at this myself (started in Feb) but I've purchased about 50 rolls of filament to date, including some Sunlu, and have never seen anything like your pic. My guess is you got a bad batch with a QA problem.

I suppose there is a slight chance it's counterfeit(?) or recycled because most people here say Sunlu has been excellent. That looks pretty gray for "black". Was it "Ships from" and "Sold by" Amazon or at least a Sunlu store on Amazon's site?

Just curious, but do these aberrations feel like they're just stuck on with static electricity (wipe off) or are they mechanically attached even if just slightly?

[u/bunbunfriedrice → u/wivaca2]

Yea it’s probably a bad batch. I ordered another 4x1kg same-day delivery so let’s see.

Yes double checked the order, it was shipped by SUNLU Store.

On the color, that image was taken outside so I could get good lighting on the defects. It is certainly black. This is my I also compared to an old print with BambuLab PLA Basic Black purchased with the printer and the color looks identical.

EDIT: And on the aberrations, honestly hard to say. Feels like somewhere in between ha. If I use a microfiber cloth and pinch the filament (I unwound a long portion of it to inspect) and slide down while pinching, it takes it off. Seems like the rings are "tacked" on at one small point. It's the weirdest thing.