I print a lot of model railroad parts with large flat areas (2-3" square up to 3" x 5.5") but each part, regardless of resin or layer thickness (Clear or GreyPro), is much thicker in the center and thins out as you reach the edges. Everything is printed at 50um and there is no post-cure UV treatment because, even for 1 minute duration, parts will curl due (likely) to varying thicknesses and material stresses being relieved differently.
I use the PreForm default for density of supports with tips at .15mm, mini-rafts and 2 mm above raft. Because these parts will be used as mold patterns and represent steel sheets/plates, they must be parallel to the platform. I’ve tested a couple smaller pieces at 10 degree tilt in 1 axis and this problem goes away but even a minimal stairstepping can’t be tolerated.
Are there advanced settings in PreForm that can be tweaked to correct this problem? Several years ago, I used to buy Prototherm SLAs from a service bureau who printed parts on a Viper and those flat parts had the same cross sectional thickness end to end so I know it can be done but not sure if it’s possible with Form3.