Trying to avoid curling on large prints.

Trying to avoid curling on large prints. Since I’m using Kisslicer which doesn’t have a brim feature I created my own brim right in the model but how thick should I make the brim. I believe I understand the thermal dynamics of why the part curls. As layers are laid on top of each other they cool and shrink a little so as the upper layers shrink they pull on the lower layers which in turn curl up. So at what point do the lower layers start to curl. I want the brim to be thick enough to keep the part from curling but not so thick that the brim itself starts to curl. I was thinking around .25 mm am I correct in my thinking.

Yep. Basically. I use a .2mm brim and it does the job for the most part. I still get lifting on large parts with solid infill though. Only thing that helps there is raising the ambient temperature of the build volume.

This is going to be a part for my Prusa i2. I am moving the extruder so that it hangs off of the end of the threaded rods at the top, next to the right Z motor. I’m using a 35% infill ,hopefully that will be strong enough.

I use like a 5mm-6mm brim (width of the brim from the object). It’s not like it uses a bunch of extra filament. It only needs to be a single layer high though, so that depends on what layer height you’re slicing at. If you’re slicing at 0.1mm layer heights, make it 0.1mm thick.

Keep any and all drafts away from the printer. Seriously, even walking by the printer and the draft removing all that heat can curl a print.

You can also do things like make the skirt height higher than 1 layer so that it helps shield your print from drafts

There’s a setting somewhere in kiss where it builds a skirt/shell to keep the drafts down. My low tech solution is to drape my mendelmax with a fire retardent sheet. Keeps out drafts and increases ambient temp but not to the extent the stepper overheat. @Mike_Smith push up your loops count and wall thicness if you’re worried about strength, also raise your extrusion temp a bit to improve the plastics bonding.