Got a pic of it this time,

Got a pic of it this time, seems like when I’m printing overhangs the shell gets ahead of the z-axis. Tried dropping the temp but I’m wondering if its a steps per mm error or something?

If this is PLA, use a fan. Had the same thing while printing tornadoes, threw a fan on it, and all was fine.

Im using a fan but I’m wondering if its not powerful enough (I just pulled it off a QU-BD extruder I’m not using)…I’ll try a bigger fan, thanks!

Most likely that it is curling inwards and upwards with a circular overhang like that. You probably need a fan to cool the object so each layer sets hard before the next is laid down.

I’ve read that the shape of the fanduct / fanholder /nose is also very important. It could well be that the air is not correctly guided to the printed part.

Something like this works well I am told:

Yeah @nop_head what I’m using now is nothing that fancy, just a little fan hung off the x axis near the nozzle. I’ve seen some ducted designs that I’ll try in addition to a more powerful fan. What are you using @ThantiK ?

A small desk fan.

It’s curling up around the outside of curves. Try a square and you’ll see the corners turn up. I’ve found that this can be reduced by reducing the temperature to the point where you HAVE to really slow down to make it extrude, get your extruder tight too.

Interesting. I’ve had no problems like this with straight walls but I haven’t done any overhangs that were not circular so I have some experimenting to do. I’ll also try slowing down to see what changes. Thanks for the tips!

Well straight lines don’t curl up. I think it’s the path you’ve extruded shrinking and riding up and inward on curves. I’m told Slic3r accounts for this effect in curves and corners, maybe that value can be adjusted (it’s not in the GUI).

I can’t think of a way the slicer could compensate for it other then slowing down. The problem is the plastic shrinks after being laid down and if the layer below is not hardened it curls up. It then starts to brush against the nozzle when it is doing outlines and gets kept permanently in a soft state.