To provide a method of manufacturing a film roll which has favorable appearance without utilizing oscillation.
A method of manufacturing a film roll includes: (A) a process of continuously supplying thermoplastic resin to an extruder and extruding from a die, and forming a film while traveling; (B) a process of adjusting a film thickness by repeating a step of creating an individual thickness profile by measuring a film thickness during film traveling once at each predetermined interval, a step of creating a measured thickness profile based on one or more individual thickness profiles, and a step of adjusting a lip gap based on the measured thickness profile and a set thickness profile; and (C) a process of winding the film in a roll shape. In the process (B), the film thickness is adjusted so that a degree of a variation (R1) of the measured thickness profile per one unit and standard deviation (σ1), and an average degree of a variation (RAV) of integration average profiles calculated by arithmetically averaging the measured thickness profiles per 100 units which are continuously created, and the standard deviation of an average thicknesses (σAV) are in predetermined ranges.
HATAKEYAMA KAZUHIKO
ESCARBO SHEET CO LTD
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