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I am printing a part with overhangs with PLA, see attached. The beginnings of the overhangs want to curl up like a flower petal. Is this from too much fan cooling? Or is it something else?

Did you read the section of my guide that talks about overhangs? It looks like these are quite severe overhangs and you should set expectations accordingly.

I read your section on overhangs. Currently the way I have MatterControl setup is to print the exterior perimeter after the interior perimeter. Is there anything else I can do? I am using 3 of those 25mm squirrel fans with the open bottom shrouds. So i guess I'm a fan boy. Should I tone it down and go with a more directed jet at the tip?

galesc, if you're seeing curling it's because the PLA isn't getting a chance to cool down. Slow down the print and see how it goes.

g.

With such severe overhangs you need to try to freeze the extrusion as quickly as possible. As Gene says, slow down and use as much air as you can directed right at the overhang. But this is an example of a model that wasn't really designed for effective 3d printing. I don't know what the part is but if the protrusions ha a more gradual slope they would print a lot better. A 45° slope is really the practical limit.

All, thanks for the advice. I'll slow it down for overhangs and direct the fan on it. This part is for my RC truck. I designed it for a CNC machining operation, so you are correct about it's design intent. I'll make modifications or split it in half for future prints. Thanks!

Can you flip it over? Not sure what the top looks like but if it is just an extension of the top layer, flipping it would eliminate the overhangs.

It's symmetrical so that wouldn't help unfortunately.

Which RC truck?

It's for a track system I built for T-Maxx's.

Very cool.

Two alternatives come to mind - the brute force alternative and the elegant alternative:

1) Brute Force - print in two haves and print them with the mating surface down. This will eliminate the overhang problem.

2) Design in a simple breakaway support for each of these. A "Z" tower printed up to each would do it. Johann's Ball Bearing Kossel Carriages have a very elegant "Z"(zipper) support that works great and zips off cleanly. Since you designed this part, you have the tools to do it and it would give you a lot of cred if you did and published the process!