Printing speed for ABS, underextrusion and nozzle clogging

[axsdenied 0]

Hi

I have recently moved onto ABS from PLA. I was not sure how fast I could print so I did the "Can your UM2 printer achieve 10mm3/s" with ABS. No issues reaching 10mm^3/s at 260 degrees C, ABS seems to flow much better than PLA.

So I tried printing an object at 7mm^3/s and the printer run for about an hour before it suddenly stopped extruding. Before I knew what was happening the nozzle was blocked and the filament was ground on the feeder.

After declogging the nozzle I tried printing something else, again at 7mm^3/s. It printed for <20min when I noticed that it started severely underextruding. No clicking from the feeder but hardly anything was coming out of the nozzle. I lowered the printing speed to 80% and things went back to normal.

After that I printed several objects at 5mm^3/s without issues.

I should note that all objects were quite simple with hardly any retractions.

So, why do I get underextrusion/clogging after while when printing faster?

 

[cloakfiend 994]

Not sure what condition your ultimaker is in, but the nozzle is clearly still jammed, i print from 35mm to 70mm with no real issues.

Just get some white pla or something and do the atomic pull method btu make sure you do it in a corner so not to bend the bar as i did once, but managed to bend it back. thank god.

Use white, as when you have bits of tiny dirt still stuck in the nozzle they are much easiler to see than with any other material. i thought i unblocked my nozzle for ages until i used white.

The main thing for nozzle jams is temp. sometimes i print slightly hotter to get the material to pass through, also if im printing in 0.2 (to get better flow).but again, if you have to do this your nozzle is still jammed.

Unblock it and youll be fine. 50mm speed is fine for 0.1 thickness of abs or pla at their default temps unless you are using some kind od exotic materials.

 

[neotko 1,417]

Maybe be the feeder needs some cleanning and tension checking. Wtry cleanning the round metal (drive) and check the tension. Ofc It can be other stuff but I lost 3 days checking/cleanning nozzles/etc and in the end was a feeder problem

[tsagos 8]

You dont mention any temperatures. What temp you use? Can you see any skipping on the fillament?