Curling Edges (NOT FIRST LAYER)

Hey, Ive been working on this problem for a could months now but unable to figure it out, whenever i'm printing anything with a slight overhang in PLA (anything with a vertical layer less than 90 deg.) the perimeter on the overhang curls up, each layer than gets worse and worse untill eventually it knocks the part off the print bed. i've set my speeds from as fast as possible down to a slow crawl, around 20mm/s, with no results. any help would be awesome! again this is not caused from the first layer peeling up, it usually starts about 5 layers in.

Do you have a fan on the part? What temp are you printing at?

I have a little 20 mm fan on the extruder, 190 extruder and 60 bed

With PLA it is best to have a fan blowing on the part. I currently have 2 50mm fans on the left and right of my extruder to cool the part. You will notice a big quaility improvement with a fan. I was surprised at the difference it made. Overhangs are tough with out them using PLA.

Edited 1 time(s). Last edit at 04/12/2014 08:37PM by cat.farmer.

Ok, Thanks for the advice, I've just hooked up a huge 200mm fan and running a part now, I'll let you know how it goes.