Support Material-Based Prints Having Trouble Completing

[Zulfe]

I'm trying to print ZortraX's Low Poly Tiger (http://www.thingiverse.com/thing:347687), which required support material for the majority of the print. I can get the body to print fine, but the tail on my first attempt was atrocious. If you look at the images below, you'll see that the tail completely failed to print, and I think even damaged the rear leg, because I found it knocked over when I got home and checked its progress. Before leaving for school, I noticed that the ends on the tail, when it first started printing, had started to warp; therefore, when the nozzle went over it to add the next layer, it pushed the portion down which then bent back up. Do I need a fan focused on the filament in order to print this? It seems like the filament is staying malleable even after sitting for 30+ seconds (while the rest of the support material and legs are being added on to.

I'm also getting these brown boogers when I print with white/natural. Anyone know how to stop them? (Image below)
IMAG0323.jpg

IMAG0322.jpg

[printbus]

I don't recall what your hot end is, but I've seen the "brown boogers" when my hex hot end shroud was melting and dripping onto the print.

I have found it to be surprising how long PLA retains heat - especially heat built up across multiple layers. A print cooling fan works wonders, but you don't want to cool the nozzle too much or the bed, if you're running heated bed. What I would do to get through the legs without a focused print cooler is set up both a high minimum print speed (IDK, 20 mm/sec?) and a minimum layer time of 30 seconds or so, and then tell the slicer to lift the nozzle away from the print if it has to while it waits on the layer time. I've even watched a couple of prints that I knew were going to be touchy as far as heat, and hit them with a small bit of compressed air on occasion to cool the sensitive spots.

[Zulfe]

I don't recall what your hot end is, but I've seen the "brown boogers" when my hex hot end shroud was melting and dripping onto the print.

I have found it to be surprising how long PLA retains heat - especially heat built up across multiple layers. A print cooling fan works wonders, but you don't want to cool the nozzle too much or the bed, if you're running heated bed. What I would do to get through the legs without a print cooler is set up both a high minimum print speed (IDK, 20 mm/sec?) and a minimum layer time of 30 seconds or so, and then tell the slicer to lift the nozzle away from the print if it has to while it waits on the layer time. I've even watched a couple of prints that I knew were going to be touchy as far as heat, and hit them with a small bit of compressed air on occasion to cool the sensitive spots.

I'm using the 0.35mm J-Head hot end. I'm printing in ABS. It wouldn't be a problem to print a cooling shroud, I just don't have a fan to mount onto it yet. I also have no idea how to lift the nozzle away. I just said 30+ seconds because it works on the rest for about 30 seconds before returning to the tail part. How would setting a high minimum print speed help though? I need the filament to cool before continuing.

[printbus]

How would setting a high minimum print speed help though? I need the filament to cool before continuing.

Setting just the layer time will cause the slicer to slow down the nozzle as required. IMO, the risk with this is that the nozzle can end up moving very slow, providing a lot of time for heat to be passed from the nozzle into the printed part, remelting the layers below as it creeps along. Increasing the minimum print speed will only allow the slicer to slow down to that value. It could be that the lifting of the nozzle is automatic - I don't see a setting for it in Slic3r. Sometimes I get all these slicers confused. EDIT: In Cura, this is the "cool head lift" setting.

[printbus]

You really could use someone else's inputs. I'm not sure how much what I'm saying is going to help vs. hurt with ABS. I know if I was printing the thing in ABS, my problem would likely be layer delaminations in the legs as they cool.

[dacb]

What temps are you running?