In a previous job I have some experience of blanking plastics (credit cards) the main things are to keep the punch and die clearance tight 0.0005” / side, make the stripper a running fit, make sure the punch and die are sharp, polish both if you wire erode and have a compound angle on the front of the punch. This will however change the dimensions of the blank if it is a tight tolerance, you will have to experiment with this or calculate it, I cannot remember what we did.
I hope this is of some help, but might not be depending on what you are trying to do.
