Having Overhang Problems With ABS

[benjamin-krygsheld 0]

Just got my printer this week and have been having a blast. Decided to switch from PLA to ABS, and having nothing but problems. Oddly I've had 0 problems with bed adhesion with ABS. Most of them I've managed to sort out, but my biggest issue is still with over hangs. Any part that has any overhang what so ever is just turning out like straight garbage. Which is a shame because after I figured out the pillowing problems, my top areas are beautiful.

I'm printing at 250 C fans at 25% right now and have built an enclosure for the build area but this doesn't seem to have made much of a difference. Other settings are Layer Height: .1, printing speed 50. I'd like to stick with ABS due to its higher heat tolerances and ease of finishing but this overhang problem is killing me.

 

[benjamin-krygsheld 0]

http://i1072.photobucket.com/albums/w375/Benjamin_Krygsheld/Facebook/Mobile%20Uploads/11018142_10153290310833969_5874468601655376441_n_zpswhrwkrmz.jpg

Back of object

http://i1072.photobucket.com/albums/w375/Benjamin_Krygsheld/Facebook/Mobile%20Uploads/11129894_10153290310968969_2641073934283656841_n_zpsumjntmvg.jpg

Front

 

[gr5 1,967]

If you enclose the front and more importantly the top, then you can up the fans a bit. Fans tend to reduce the quality for ABS a bit but you need them for good overhangs. I'm really not an ABS expert but I recommend more fan. And especially go for the enclosure as you want more fan but with warmer air.

If you cover the top of the printer with one of those boxes that holds copier paper it fits perfectly and leaves a reasonable size hole in the back where the bowden is but facing downward. Combine that with a sealed front and 100C bed and you get about 40C air temp inside which helps reduce shrinkage. Let it warm up in there for a while before you start printing.

 

[gr5 1,967]

I've seen older slicers (before cura) that were written back "before pla" and those are funny as the fan will come on for just a few seconds during a bridge or overhang and then shut completely off again for the rest of the printing.