Patent ID: 7695263

Claim:
A film die for the production of tubular film made of thermoplastic synthetics, the film die comprising at least one synthetic fused material feed channel which terminates in a ring-shaped discharge nozzle, at least one of an interior and an exterior cooling ring configured for a diameter of the tubular film, the tubular film being divided along a length thereof into sectors in which physical parameters of air blown onto the tubular film can be variably changed sector by sector such that in a portion of the film die associated with at least one of the sectors in which temperature is individually variable, the film die includes (i) heating cartridges therein and (ii) conduits arranged across a circumference in the film die from which the air is discharged, the air conduits being essentially aligned vertical to the exterior cooling ring, and at least one control unit that controls the physical parameters in order to influence a thickness of the film, the sectors in which the temperature is variable and the sectors in which the physical parameters of the air which is blown from at least one of the interior and the exterior cooling ring onto the tubular film are variable being arranged in a circumferential direction of the tubular film in relation to each other such that the film die has ranges of the sectors which overlap one another with an overlap angle that is smaller in the circumferential direction of the tubular film than is a sector angle of an individual sector.