You have not done anything wrong!
Usually, each resin type is suitable for a specific VAT floor. For example, for PDMS floor you should use very specific types of resins.
FEP is known to be very strong and difficult to ruin. But still a couple of things you need to consider:
When the resin cures it does generate a substantial amount of heat, you definitely ...
SLA prints are usually very glasslike in their internal structure and thus are often quite brittle: They tend to break with a very distinct, sharp failure mode. Their compression strength is often high but their tensile strength is limited, and their resistance to side loads is low.
Due to the printing method solidifying the resin layer by ...
In my experience, when I had the same issue happening it was because my first layers exposure time what too short.
I was experimenting with bottom exposure time (in order to reduce the elephant foot) and sometimes, with very low exposure's time, I had failed prints that didn't even adhere to the print plate and remained stuck to the FEP (exactly as it ...
I'm an owner of both an FDM printer and a resin one:
I've long searched a resin capable of printing durable objects even in tiny details but with poor luck. I've tried ABS-Like resins, and they provide a slightly better resistance than regular resin but do not expect great improvements; I've tryed the siraya tech Blue V2 that is for sure much more durable ...
The rook is normally difficult to remove, it's designed this way.
Have you tried resetting the height of you build Plate?
If it makes a grinding sound when doing the first 2 or three layers your build plate might be traveling too low.
Also try re-leveling your build plate, e.g. I pushed so hard when I tried to take my rook off that I un-leveled it.