US Patent 7588709 Casting device, solution casting apparatus and solution casting method

In a casting process of a film production, a casting dope is discharged through an outlet of a casting die. In the casting die, lip plates and inner deckle plates are arranged such that a lower end of each inner deckle plates may be form a protrusion at a side edge of the outlet of the casting die. Each protrusion length from a bottom of the lip plate is at most 9 μm. Thus the retaining of the casting dope near the outlet through a dope passage in the casting die is reduced, and therefore the skinning doesn't occur in the casting dope.