[FrankJ]

To restate what others have already said.

Plexiglass is a brand name of acrylic.

Lexan is a brand name of polycarbonate.

They both have their advantages, but acrylic is brittle compared to polycarbonate.. You should avoid using for shields and structural partc. It is nice for fish tanks if we ever have a water game. One easy test to tell acrylic from poly. Hit a piece hard against a table top. If it cracks or shatters it is probably acrylic. Wear your safety glasses. So in the robot world. Lexan=polycarbonate=good. Plexiglass=acrylic=bad.