I'm trying to print  http://www.thingiverse.com/thing:59370 without support but having trouble with the overhangs.

I’m trying to print http://www.thingiverse.com/thing:59370 without support but having trouble with the overhangs. They get printed fine but tend to curl upwards until the curl amounts to so much that the print head starts hitting the edges. I’m printing with PLA at 165°C and two fans, but still having this problem.
Is there a way to tell slice3r to wait inside the model for a few seconds after each layer, so the borders have time to settle?

Cool might be your best bet here - increase the minimum layer time until you find a vaule that works. Your heated bed might also be cranked up too high.

Yes, use the cooling page to slow small islands down, also try to get your extrusion temp as low as you can. It was a much harder print before they made the legs fatter. I found I needed a 0.5mm Z lift.

So, the value I adjust is “Slow down if layer print time is below”, right? How low can I go for minimum print speed?

@Bracken_Dawson what do you mean by “0.5mm z lift”?

@Andreas_Gohr that’s the one. I’ve got it at 35 seconds for 0.15mm ABS layers.
@Bracken_Dawson yeah, that as cold as possible myth. It’s fine to use super-low temps (165 is already really cold) when you have a shoddy hotend and are only going for small decorative prints. However, inter-layer adhesion will suffer from low temps, often enough to have your model tear itself apart during the print. Additionally, not every hotend gives the same temp - in the end, you’ll have to make the tradeoff between mechanical strenght and detail reproduction yourself.
I run my ABS at 245C, which gives super-strong and still very detailed part.

@Andreas_Gohr You can also have your extruder rise up as well as retract when doing long enough moves.

@Thomas_Sanladerer I do print a bit higher than I need with my lovely stable ABS, 230 on my thermistor. But I’ve never really been able to give PLA the same treatment and it not go mental throwing loops of all the walls. Maybe it’s my batch, maybe it has water in it. I do notice that it curls up less printing cooler, but I do also notice I can sometimes peel my decorative parts apart. I tend to stick to ABS for the functional parts. I think you’ve given me the push to start exploring hotter temps again, so thanks for that comment. There’s always so much on the to do list with my printer.

@Bracken_Dawson ahh I just noticed that option. I have print going right now, if that fails again I’ll try the Z-Lift - sounds very useful. Thanks for the hint.

hmm cooling towers are a clever idea.

sigh I think give up. I tried cooling towers but the longer cool time do not prevent the curling. The head just kicked one of the front legs off the plate. I’ve wasted a whole bunch of filament by now, but I can’t make it work.

I have two fans. This seems not to be a cooling problem. The perimeter curls up right after extrusion. Better cooling just hardens it faster in its wrong position :-/

Try slowing your print speed down so the nozzle will act as an iron to smooth out the curl. I’ve had this issue when printing this stupid frog for a friend at fast speeds. I sliced the frog twice once at my normal printing speeds 80mm/s and once slowed down to 10mm/s and put a 1.5mm z lift. I cut the slow speed one a 2 layers after the front legs get attached to the body then combined it with the faster print speeds to finish it off and I was able to get the frog to print after wasting at least enough plastic for 10 of them.

@Andreas_Gohr curl as it’s commonly known as, is very much a cooling-related issue. When the previous layer is still too warm and soft to resist the next layer’s contraction force, the topmost layer will contract more than it should and pull the lower layers up along with it.

Slic3r 0.99 can do the perimeters from inside out, which should help prevent dropped loops on overhangs. It can also do infill before perimeters, for the same reason.

i had that problem when my cooling wasn`t at the right place…now i cool only exactly around the nozzle and have a more direct cooling…no curling anymore

@Rznag_Rmrod hmm that would be ideal, but I have no idea how to achieve this on a Huxley

ive tested this frog some minutes ago...printed at 100mm/s, total print time 19min at .2 layer height...looks not that bad, but a little bit slower would be probably better or i need even more cooling :) fan running at 100% wasnt enough cooling at this speed
i use this fan duct, think that should be possible on a huxley too: http://www.thingiverse.com/thing:63123