4mm Thick "Wall" Print keeps failing

[luizzanotello 0]

Hello all,

I have made three consecutive tries printing the attached file with black ABS (2.85) in an Ultimaker 2 Extended, and I keep running with an error exactly at the same point of the print every time (you can check the failed print bellow too).

FILE / Cura configuration:

http://imgur.com/a/ggzOI

Failed print:

http://imgur.com/a/kHB13

I have printed the same file with PLA (of course with a few different configurations) and it worked fine.

Any suggestions?

Thanks!

Best,

Luiz.

[gr5 2,172]

That's just basic underextrusion. I would try printing either a little slower or a little hotter. I can see underextrusion in that wall and also underextrusion near the top and then it basically stops extruding at all and makes a stringy mess.

I'm not sure what is causing your underextrusion - there are so many possible causes but I'd start with speed and temp. Especially temperature. What temperature did you use? I usually go for around 245C. Once I clogged a nozzle because I printed too hot (254C that time - yes exactly 254) and I let it sit a little too long in the nozzle (a minute?) at that temp and it baked into a gummy mess. I was able to get it out by heating the nozzle alone over a gas flame to about 200C and removing with a toothpick.

ABS has a much narrower temperature range than PLA. PLA is pretty good from 180C to 240C.

[luizzanotello 0]

That's just basic underextrusion.  I would try printing either a little slower or a little hotter.  I can see underextrusion in that wall and also underextrusion near the top and then it basically stops extruding at all and makes a stringy mess.

I'm not sure what is causing your underextrusion - there are so many possible causes but I'd start with speed and temp.  Especially temperature.  What temperature did you use?  I usually go for around 245C.  Once I clogged a nozzle because I printed too hot (254C that time - yes exactly 254) and I let it sit a little too long in the nozzle (a minute?) at that temp and it baked into a gummy mess.  I was able to get it out by heating the nozzle alone over a gas flame to about 200C and removing with a toothpick.

ABS has a much narrower temperature range than PLA.   PLA is pretty good from 180C to 240C.

Thank you! I will try that out. I thought it was weird for it to be only an under extrusion problem, since all the other parts worked fine (and it literally always fails at the same place). I was wondering wether it had something to do with the new algorithms for generating the gcode from Cura (since I have never run into such problems around a year ago, with a deprecated version of the software).

I have printed it at 240C (for this specific ABS the specs said from 230 to 245C). I will try raising it to 245C and lowering a bit the speed.

[IRobertI 520]

Interesting that it seems to start happening where you have some retractions starting to happen more often with the small islands. What does the filament look like? Is it flattened at all?

[gr5 2,172]

Ah - you didn't mention about the firmware. Cura 2.* does some weird things with print speed. Consider making all the speeds the same. I don't think this is the issue but other less critical surface ugliness I've seen caused by speed changes. Again I don't think this is your specific problem but definitely have a look at *all* the print speeds in cura 2.*