A method for spreading and cutting flexible sheet materials

摘要

SUMMARY OF THE INVENTION Accordingly with the invention, during the spreading phase, plies stacked in each cutting position can be separated into different groups by applying one flexible film ply, called "separator film" between groups. The application of the separator film is provided by means of a "separating spreader". It is desirable to provide an apparatus for separating plies that is efficient and does not increase sheet material spreading time. It is an object of the present invention in its preferred embodiment at least to provide a method for applying separating film that minimize the time required for spread separating film. It is a further object of the present invention in its preferred embodiment at least to provide a method for accommodates a separating film at different heights at different cutting positions in the lay-up. It is a another object of the present invention in its preferred embodiment at least to provide a method that ensure that the separating film is applied without both stopping the sheet material spreading and requiring a spreader set-up operation. Moreover in accordance with the present invention, the spreader is provided by an innovative operating method oriented to the minimization of the number of lay-ups formed Indeed, the lower are the spreading time and the cutting time spent to process the current workload, the higher are the productivity performance of the system. Since the cutting patterns are pre-established, it is an object of the present invention to provide a method to compose single lay-up in order to maximize the length of spread plies (i.e. to minimize supply roll changes and the number of distinct spreading operations) as well as to maximize cutting positions heights (i.e. minimize of the number of cutting positions). The provided method is subject to constraints inherent the spreader worktable length and the maximum number of plies that can be cut at once. It is a further object of the present invention to provide a method to manage the spreading operation taking into account the mirror properties of cutting patterns, placed in contiguous cutting positions.