I've searched the forum for 'corners, lifting, curling' but haven't found anything that sounds like this. Apologies if I've missed a previous entry on this topic.
My first level lays down well and sticks (as does the skirt.) Subsequent layers go down nicely. However, on the corners of prints that are thicker than 1/4", about 2/3rds of the way through the job, the corners start to curl up and lift off the plate.
The top of the print remains flat and the rest of the print retains a really strong adhesion to the plate. It _appears_ that the problem gets worse as a function of distance from the center, but it's not consistent.
Printrbot Plus, problem prints are ABS, bed temp is 90 for first level and 95 for subsequent levels.
This picture shows the problem with the corners (and the side extrustions):
curling.JPG
Any help appreciated!
--tim