About Acrylic|PMMA (polymethyl methacrylate). Crystal-clear optical transparency (92% light transmission). Better clarity than
polycarbonate but dramatically more brittle. It cracks and chips if you look at it wrong. Machines with care: use very sharp tools, moderate speeds, and avoid chatter or vibration. Drill slowly with peck cycles to avoid cracking. Used for displays, light guides, lenses, and decorative parts where optical clarity is the priority. Compare to Polycarbonate (tougher but less clear) and glass (harder but not machinable).