What causes lines in the middle of a 3d print? Solve under extrusion problems mid print, halfway up!

So annoying when you come back to a print that was going well to find these naughty missing lines in it.
WHY DO THEY HAPPEN?!
Well, underextrusion and a partially blocked nozzle obviously. But there's more to it than that. Possibly.
No Eevees...were...harmed in the making of this video. Honest.

Please comment if you have anything to say!

Credits:
Licensed under Creative Commons: By Attribution 3.0 License

The Lift by Kevin MacLeod

Voxel Revolution by Kevin MacLeod

[rich]

With a hardened nozzle, make that 220C. There is a larger temperature swing on hardened nozzles because of the lower heat conductivity, and you need to compensate or you will have under extrusion issues like this.

[Mino_]

There's a similar problem with infill that leaves under extruded sections in the same spot in each layer. It's caused by the having any friction on the heated bed cabling. The cable will pull taunt before the tension is released causing the nozzle to move too fast across the print leaving stringy bald spots in the infill. This happens consistently in each layer creating large voids in the print.

[trentv]

Thank you so much! I recently started printing much larger objects and got the under extrusion starting about 2cm up and it was driving me crazy until I found this video.

[aldinbalagic]

I can`t believe that this was the answer to my issue, after all i tried to get rid of the problem it turns out its very simple! Thnx for the great video

[RenotSemaj]

A very timely video. I had this problem this morning. My solution was to print slower, not really knowing the cause. I will try a higher temperature now. It really helps to know why things happen. Thanks: Latitude: -43° 31' 59.99" S Longitude: 172° 37' 59.99" E

[Grenoble]

thanks a lot. i’ve watched hundred of 3d videos, but this is the first time i see this explained. Saved one of my pla reels.

[mahreeortiz]

Man, you are smart as heck. Thank you so much. My printer is doing this EXACT thing. Stringing back and forth and then skipping layers. The first few hours worked amazing then it starts skipping and stringing, then it prints great, then goes back and fourth. Thank you for this video.

[jasond.valentine]

you, kind sir, absolutely saved my brain. i have been for the last two days investigating this topic and i had no clue. earned my sub. thanks again!

[danielcimanes]

thank you! we need more of these 'straight-to-the-point' videos.

[japreet_kah]

one of best videos ive ever watched on youtube, i am not going to pillage the rest of your videos

[rdoddsable]

Great video. I was printing some things using vase mode or "spiralise outer contour" with no problem, but when printing something more solid, the nozzle kept blocking around the same height. I couldn't understand why and never thought the residual temperature from the bed could be an issue the higher the nozzle gets, until I saw your video. Hopefully this is the reason my print is failing and I can resolve it. I have a printer enclosure that I haven't used yet, but I'm going to set it up tonight and see of the increased temperature helps. I also heard that with larger prints, sometimes the filament sensor can cause the filament to bend to much and stop it extruding properly. This isn't an issue for mine but thought I would mention it in case it helps anyone else. Thanks for the video, liked and subscribed!

[XempegeX]

Dude you really put in work for this, not just talking about stuff and thats it, but actually getting things under microscope lol :D Thanks

[NerdBeGaming]

Wow thank you so much I’ve been struggling for so long with this problem not being able to diagnose it this video does a really awesome job at explaining the problem

[cavinrauch]

I never print lower than 220c for PLA but my speeds are slightly higher than normal though. But even at lower speeds I prefer the strength of printing at around 220c.

[dleivam]

Awesome.. A long time ago I tested print an object with the same filament at different temperatures and at 195 c I got the best looking part, but the layer adhesion was weak.. At 215 c I got the strongest part but a lot of stringing, so at the end it was a compromise between those two.

[frikkiesmit]

I was busy to print a month ago and got a weard underextrusion. And one guy said i must check the geer at filament feeder if its not dirty and causing filament to slip. So one night i removed that arm thats under spring tension and that plastic arm .... had a crack in it!!! So i was lucky to be blessed by the man where i bhought the printer who gave me his old spares which where still in good shape. I will in future get the aluminuim feeding stuff.

[Gambiarte]

There is another thing that can cause lines in the print.
If the extruder clicks, it is possible that the driver is overheating and turning off for safety reasons. When the temperature drops, it turns on again, this causes the extruder to click as the step is no longer matched.
Possible solutions are: Improve the cooling of the extruder driver or reduce its current.
The driver current must be correctly adjusted, if it is too high it will heat the driver and can damage the motor, if it is too low the extruder will not have power to work correctly.

[purerizzo]

Great video, suffered with this a few times and painstakingly came to a similar conclusion! Thanks!

[jacobcultivates]

Excellent troubleshooting video man.
I've been experiencing this nightmare on and off for the past four years on the Ender 3 V2, and am currently experiencing it again now after switching to PETG and printing at 240 C (which is very close to the machines limit), wall line speeds 35 mm/s, with retractions about the same speed.
It's brutal with the PETG and the only thing I can think to do from this point forward is drastically reduce speeds and perhaps increase retraction distance to cut down on retractions.
It makes sense that areas with high amounts of retractions will influence this issue because of the pull/push/heat drop off, then trying to get it back to its normal flow rate while influencing the heat drop on the hot end.
Hopefully slower speeds will work or I might be forced to only use PLA on the Ender 3 V2 : (
Thank you for helping with solving this issue.

[ScottPSilver]

Thanks temp and a drastic decrease to the retraction setting fixed my issue.