In this video I show a simple set up for an acrylic plastic snapping jig using scrap pieces of sheet material secured with g clamps. The plastic sheet is then scored using a knife along the top edge and the protruding end is clam between two pieces of sheet material before making the snap.

This is a simple set up but it would not be difficult to make a jig which had a positive stop to keep the front surface of the jig lined up and with inserted nuts to clamp material down. I know this because I’ve already built one at work.