I am coating a UV curable ink (film thickness ~5 um) onto a thin (1-2 mil thick) PET plastic substrate. I want to cure it by running it through a UV curing system which has a bulb operating at 300W/in. with a belt speed of about 50 ft/min. I am having problems with the plastic crinkling up into a ball when its being passed through the UV cure. This I originally thought was due to the heat being generated inside the UV system. But when I pass bare plastic film through the system it doesn't warp or crinkle as I've seen before (although the film does feel hot when removed). It seems to me that the UV cure is hardening the ink so fast that it warps the plastic and causes this incredible deformation. I still haven't found a way to cure without ruining the sample. The ink needs 300W/in to properly cure, although I can also try a lesser power bulb. Would a better cooling system help, or is this a problem with the ink/substrate surface relationship?