PET sheet extrusion line developed by our company with its screw and barrel of optimized design possesses compact structure and exceptional performance. The whole unit holds the features of even plasticization, stable extruding, high output, long life span, etc. The accurate calibrating and calendaring device with its favorable adjustment function realize excellent calibrating. PET sheets produced by this line can easily be made into diversified packaging products after thermoforming, and are characterized by very good air insulating property without any addition agents, and are of purity and sanitation, excellent toughness and ductility, as well as reclamability. They are widely used in all sorts of packaging and printing fields such as electrical appliance, toy, foodstuff, medicine industry etc.