"Elephant Foot" at TOP of prints!

[TheModelBoatGuy 0]

Hi, I am using Cura with a Snapmaker 2.0 printer to print parts that are typically 200 x 200 mm at the base by say, 120 mm tall. Each of these parts are sections of the hull of a model ship and are roughly a 'U' or 'V' shape. At the top and bottom of the parts (direction as printed) there is a 3mm thick flange (or "lip") which will be the seam where adjacent sections get glued together.

These flanges seem to cause my parts to curl or warp outward at the top edge as shown in the attached photos. I experimented with making the flanges thinner (1.5 mm) and it seems to reduce the effect, but unfortunately, they are required. I also experimented with another printer (Flashforge Dreamer) but it seems to do the same, so I'm not sure if it's an issue with Cura or a more general 3D printing issue. 

 

The print material I use is eSun PLA+ and most Cura settings are default, except for the slightly higher nozzle temperature of 210 deg which is recommended for PLA+ (as opposed to PLA).

 

Can anyone offer advice?

 

Thanks,

 

'JP' (TheModelBoatGuy)