I've never had this issue before with PLA warping. I use Aquanet on a glass bed. Cleaning with IPA after each print.

But I never had done long prints (4-6 hours) with 60-70% density. I've gone down to 205° and left a small desk fan running by the printer. I haven't had an issue since then.

Here is picture of one of the almost completed roller assemblies.


20160202_074846-1.jpg