| 摘要 |
A method and apparatus for making bags is disclosed. It includes receiving a film and imparting a plurality of successive seals to the film to form bags. The location of the imparted seals is determined by monitoring at least two sensors. A plurality of perforations are imparted to the film at locations relative to a corresponding seal in response to the determination. The position of a perforator such as rotary position, of a knife may be controlled in response to determining the location. The seals may be formed by a rotary drum, and the perforation by a rotary knife. The sensors may be at the same or different cross machine direction and/or machine direction locations. Startup may include adjusting and recording the position of a prior perforation relative to a prior corresponding seal, and using that recording as a base relative location in another embodiment.
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