AKA thermoforming, also very close cousins to pressure forming. All of them describe the process of taking a solid sheet of plastic, ranging in thicknesses from .010 all the way past .300, heating it up to a specified temperature
Paper or plastic?? These days, answering that question in any store will cost you 10 cents. In the world of boxes, answering that same question could cost you 7-10 times more depending on the material you choose.