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Print failure - became spongy and stringy mid-print  

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barak.o
(@barak-o)
Eminent Member
Print failure - became spongy and stringy mid-print

I was printing a 73mm high model yesterday. The first 25mm went fine, but then the print became "spongy" and "stringy" as if not enough filament was being pushed as the printer was printing. Here's how it looked after I stopped the printer:

You can see the lower part is nice and shiny, and then becomes quite a mess...

It's probably something with the extruder, as during printing, I heard this clicking noise. Here's a video I took just before I stopped the print:

Any tips / suggestions on how to solve this?

Posted : 03/08/2020 8:47 pm
Peter M
(@peter-m)
Noble Member
RE: Print failure - became spongy and stringy mid-print

Partial clogged?

Move extruder to a high point 150 mm, and extrude by hand, is filament thick enough, filament needs to go in a straight line, and no bubbles(water in filament).

Spring not good adjusted.

Too cold printing, filament is not melting enough?

What happens if you slow down?

Posted : 03/08/2020 10:44 pm
barak.o
(@barak-o)
Eminent Member
Topic starter answered:
RE: Print failure - became spongy and stringy mid-print

Progress update:

First, it's quite hard to push extrude by hand... the printer is too smart and goes into load or unload filament process.

I did feel that it's stuck, removed the filament, pushed a 1mm alen rod from the top, pushed the thin needle (that you get with the printer) from the bottom. After that, extruding filament seemed fine, but when I tried printing, it didn't last very long. The first couple of layers were fine, and then it returned to exactly the same spongy stringy print.

I tried lowering the speed, and at 30% it looked better, but I still heard some clicks (missing steps?) in the extruder.

Any other tips before doing a full scale dismantling and cleaning of the extruder?

Posted : 05/08/2020 9:05 am
Peter M
(@peter-m)
Noble Member
RE: Print failure - became spongy and stringy mid-print

clicking means, the extruder motor can not move the filament through the printer, bad filament, clogged, spring to soft(adjust this one to harder), temp to low for filament, etc.

By hand move I mean, in the printer settings you can move the extruder to the top, in z-axis, the use the extrude setting to extrude filament, look if it is thick enough, to see if you have partial clogged, or bubbles then there is water in the filament.

Even faster is put a new nozzle on your printer, then if it works then you had a partial clogged, if not then it is something else.

i had myself a partial clogged and search also a long time, after nozzle change, yes, what a difference, and before this I had tolerance problems with a model.

Posted : 05/08/2020 10:09 am
GKMAKEIT
(@gkmakeit)
Estimable Member
RE: Print failure - became spongy and stringy mid-print

Little more information would be helpful.

New printer?

Have you been printing successfully prior to this problem?

Because it's pretty consistent on where it starts to have problems I wouldn't think it's a clog. Feels like your nozzle temperature isn't staying at the correct set point as it gets higher in your print. Sometimes the wires for the thermistor or heating cartridge can be compromised and depending on the position of the print head can causes malfunctions. Have you tired printing your part in a different spot on the bed maybe near a corner?

Check your nozzle by lifting the head up, heat your nozzle to the correct temp for the filament, remove / loosen the M3x40 screw with the spring to remove tension to the Extruder-idler then try and push the filament through with your hands. It should flow smooth and somewhat strait.

Posted : 05/08/2020 1:41 pm
barak.o
(@barak-o)
Eminent Member
Topic starter answered:
RE: Print failure - became spongy and stringy mid-print

@gkmakeit - sorry, I wrote a longer post that somehow wasn't saved(*), so this one was shorter and missed some details. For completeness - around 2 y/o printer. I've printed a lot, initially with PLA, recently (few months) with PETG. Printed great in the past.

For completeness, I performed a cold pull using PLA (the instructions didn't specify if PETG can be used, and what temperature to use when pulling). While the pulled filament looked quite clean, it did fix the problem - I loaded PETG and was able to print my 74mm part. It came out accurate and shiny. Thanks.

Posted : 07/08/2020 8:25 am
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