What is the difference between Cell Cast Acrylic and Extruded Acrylic?

At PSI we manufacture our acrylic sheet using cell casting. This means we start with a liquid monomer, add our dyestuffs and other additives, pour between molds assembled from optical quality glass sheet and oven cure over up to two days. The result is outstanding optical quality, and a significantly cross-linked material that has very good abrasion resistance and chemical resistance. Cast acrylic can be bent upon heating, but is a thermoset, meaning it will not melt back to a liquid state. Extruded acrylic is made from a thermoplastic resin which is melted, extruded through rollers and cooled. It requires 500 to 1000 lbs per run, is soft, and will melt readily.