FILM MANUFACTURING APPARATUS AND METHOD THEREOF

摘要

The present invention comprises the steps of: supplying an incomplete film; clipping both ends of the incomplete film for enabling the incomplete film to receive tension in a vertical direction with respect to a moving direction of the incomplete film; preheating the incomplete film; elongating and primarily heat treating the preheated incomplete film; and secondarily heat treating the primarily heat treated incomplete film. The tension received in the vertical direction with respect to the moving direction of the incomplete film is removed in at least one step of the primary heat treatment step of the incomplete film and the secondary heat treatment step.