Differential velocity extrusion

摘要

A method of an extruded membrane of solidified flowable material having a desired curvature comprising extruding flowable material through a die in a curved section; measuring a characteristic of said extruded material at a plurality of positions along said die slot; comparing said plurality of measurements against a desired plurality of measurements respectively at each said position along said die slot and generating a plurality of signals respectively in response thereto; effecting a change in said measured characteristics of said extruded material at said positions along said die slot in response to said signals so as to produce said extruded material having a desired curvature.