3DPrinting

Something is stopping the extruder from extruding and the “fraying” is just little oozes of filament catching on the layers below.

It could be mechanical, but if it is always at the same exact layer it is may be something to do with the geometry and the slicer.

Make sure you have thin wall detection on, so it will fully print walls that are narrower than the extrusion width.

Turning retractions off might help. I’ve never worked with LW-PLA but it could be that those internal pillars getting farther from the shell are causing a retraction that jams the extruder.

Others mentioned feed, make sure your spool is not catching on the spindle. I had this issue with a roll of TPU that was too wide and it kept getting pinned when I closed the filament door. It would print fine until the tension was too much for the extruder. Then it would look exactly like this.

@i_like_water i've printed this plane twice using the same filament (3D Lab Print PolyLight 1.0), on my Prusa i3 Mk3S+; once using the pre-sliced gcodes from 3DLP, and once sliced from the 3FM files.

If you're using the gcode or 3MF files provided by 3DLP then the remaining variable is the filament itself.

3D Lab Prints filaments absorb moisture more than many othe PLA formulations. They recommend (on their Discord) to always dry new spools, and store them in a drybox.

Something I haven't seen suggested yet that has caught me up: a bad sdcard can corrupt an STL at a layer height and lead to this type of fault.

Try swapping the card while you're testing other things to see if that helps at all.

To add to the temperature comments, are you using an enclosure? PLA is known to clog the nozzle when air temperature goes over 30deg Celsius or so. If yes, try keeping the enclosure doors open (at least partly) when printing PLA.

It looks like there are multiple layers printed without feeding filament, which causes these frays to build up. Could it be that the filament clogs after this layer? Or do you see that filament still properly feeds later? This could happen for example due to heat creep and the filament getting too warm/soft in the extruder to properly feed or you trying to feed too fast.

I’m thinking it looks like the print gets to a spot where it can get faster, and your hot end can’t keep up with the temperature required by that filament, causing under extrusion. If my guess is correct, it would show on a small test print (same settings) where you get looooong straight lines to allow for speed. And would disappear by slowing down. Since it looks like a relatively expensive filament I suggest you wait for more feedback before trying my test, just in case I got it wrong and my test would waste some filament for nothing.

Have you adjusted the speed settings according to what the manufacturer says? LW-PLA can only be printed at a very low speed or else it clogs. It also needs constant speed. For example for colorfabb LW-PLA, I had to set all speeds to 40mm/s.

First thing, just because it's new from manufacturer doesn't mean it's dry. Don't know lw off hand, but drying helps eliminate variables

If it's always happening at the same layer I'm skeptical thatl it's a drying issue. You try printing with a normal pla to see if it's filament related even? If it is, agree with doing a temp tower. I've been doing that with most new filaments. Try slowing print speed too

How's your filament feed at that height, anything getting kinked or stopped? Does it feed in from a different direction? ie from low Benchtop?

Looks like your extruder can grip but not enough/ well enough for the speed. So either it's too fast or your feed is too slow. Or the temp is too low.

Have you got constant layer height set or variable? The latter could cause it too.

This looks like a clog caused by retraction.

Is it clogged when it finishes? Also, does the cooling change at this layer? Is there anything specific to this layer?

Could be too much heat so when film retracts some still drip and causes that. What temperature are you printing at?