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Did a search need some help OOZE
Posted: Tue Jul 29, 2014 2:12 am
by jprochnow
Just finished my build and on both my prints for the fan mounts during heating i'm having plastic extrude from the nozzle before the job starts. On the first mount I just left it but the second one I cleaned the nozzle off before the print started. Is there a way to eliminate this or reduce the so called OOZE?
Re: Did a search need some help OOZE
Posted: Tue Jul 29, 2014 5:32 am
by Hansen
The only easy way I know of is to reduce the temperature. There are other ways like changing the nozzle, but that would go under the "not so easy" category

Re: Did a search need some help OOZE
Posted: Tue Jul 29, 2014 12:46 pm
by gestalt73
afaik, pre-print ooze is common and normal for ABS prints, and (I assume) PLA prints as well.
As you warm up the hot end, the plastic expands, and pushes itself out the nozzle as the hot end gets to temperature.
The longer you let it sit, the more will ooze out, as you're basically heating the plastic to a liquid state, and gravity help the process along.
It's never really bothered me, because I use that warmup time to clean up the nozzle between prints.
As the nozzle reaches temperature, I'll scrub the tip a bit with a green scrubbie to remove the plastic bits, and knock off the ooze. You can't really scrub off the plastic when it's cold, but comes off nicely once the hotend is warmed up.
It's a good habit to get into, as once you get into printing, you'll start to accumulate plastic bits from angel hairs and various print failures, which then turn black over time, and can get deposited onto your model if you don't keep the tip clean.
Re: Did a search need some help OOZE
Posted: Tue Jul 29, 2014 1:03 pm
by Jimustanguitar
Somebody on the forum (Polygon or Foshon perhaps?) mounted up a wire brush and ran start GCode to wipe the nozzle clean. You could rig up something like that if you're adventurous.
Re: Did a search need some help OOZE
Posted: Tue Jul 29, 2014 1:09 pm
by Polygonhell
Wasn't me, but Nophead a year or so ago posted some GCode he was adding to the start of a print for automated starts, basically he moves the head to just above the bed (say 0.1mm) at one corner of the build surface, then heats the hotend, once it reaches temperature he extrudes say 5mm of filament to prime the extruder the performs a fast move to an adjacent corner to wipe the nozzle, then prints.
I usually like to watch the first layer start to print, so I just heat everything up extrude filament until it comes out of the nozzle, remove it with tweezers then press go in repetier at which point the print starts immediately.
Re: Did a search need some help OOZE
Posted: Tue Jul 29, 2014 1:17 pm
by Eaglezsoar
It was Foshon who created the wire brush. Link starts here:
http://forum.seemecnc.com/viewtopic.php ... 5&start=80
Re: Did a search need some help OOZE
Posted: Tue Jul 29, 2014 1:52 pm
by DavidF
I just whipe the drool, but isnt there a way to set up the printer to do a retract after finishing a print and shutting down? Would this help with the drool problem?
Re: Did a search need some help OOZE
Posted: Tue Jul 29, 2014 2:28 pm
by Jimustanguitar
You could end your prints with a big retract, and just start them with extra loops to prime it all.
Re: Did a search need some help OOZE
Posted: Tue Jul 29, 2014 4:01 pm
by Polygonhell
Doesn't really stop all of the drool, if you mess around with dual extruders you'll discover that no matter how much you retract some plastic remains in the nozzle and will continue to leak out.
Re: Did a search need some help OOZE
Posted: Thu Jul 31, 2014 2:34 pm
by RAMTechRob
I get rid of my drool and ooze when I run around the skirt.