Hexagon Head backflow

I have been printing ABS with no problem for a few months but I recently tried switching to PLA and it prints, but some oozes out of the top of the hot end. I have tried speeding up and slowing down the speeds as well as lowering the extrusion multiplier (which seemed to increase the backflow). Any idea on what to try next? I use Slic3r.

It sounds like heat is creeping up through the heat break into the cold end of the extruder. Do you have a fan pointed at the cold end? This helps significantly. Also, the cooler you print the longer you can go before oozing starts (if you don't have a fan). Try printing at 185 C (if you get poor layer adhesion at this temperature, up the temp by 5 degrees and try again).

Edit: it looks like this was answered in another thread. Can you tell us where the PLA is oozing out? If the nozzle isn't contacting the barrel correctly you may be getting ooze either above or below the aluminium block.

Edited 1 time(s). Last edit at 09/05/2014 05:00PM by 3dkarma.

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The oozing is occurring above the aluminum block. I have a fan pointed at the cool end.

Is it coming up from the aluminium block? If so, the brass nozzle hasn't been tightened on to the barrel properly. Any gap there and you'll get ooze.

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[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.