Constant pressure casting head using variably displaceable cavity surface

Abstract

A casting head having a variably displaceable cavity surface, and a method for using the casting head to produce films is disclosed. The casting head comprises a cavity, at least partially formed by plurality of surfaces, including a carrier surface adjacent the cavity, and a variably displaceable drive surface for controlling a pressure of a viscous casting material in a region proximate the carrier surface. In one embodiment of the invention, the casting head further comprises a doctor blade, disposed proximate the carrier surface, forming a gap therebetween for egress of the casting material. In another embodiment of the casting head, the variably displaceable drive surface is comprised of a piston. The piston is actuated by a driver-controlled motor according to a pre-determined displacement program, or according to the level of the casting material in the cavity. The method comprises the steps of providing a casting material to a casting head cavity having an aperture in fluid communication with the carrier surface, displacing the carrier surface relative to the cavity to deposit the casting material on the carrier surface, and displacing the casting head cavity surface to control a pressure of the casting material in a region proximate to the carrier surface. In one embodiment, this is accomplished by way of a piston which is displaced so as to maintain the level of casting material in the cavity.

Dependencies are inferred from the claim text.