System for cutting strips using helical knives and corresponding cutting method

A cutting system for cutting a continuous strip, the continuous strip extends lengthwise in a longitudinal direction and widthwise between a first edge and a second edge, said cutting system comprises:

• a drive device adapted to drive the continuous strip along a strip path at a forward speed that is oriented in the longitudinal direction of said continuous strip,
• a first cutting roller that is mounted so as to be able to be driven in a first movement in rotation at a chosen rotation speed about a first rotation axis oriented transversely to the strip path, said first cutting roller being provided with a first helical blade that extends helically around said first rotation axis,
• a second cutting roller that is mounted to rotate about a second rotation axis in a second movement in rotation in the opposite direction to the movement in rotation of the first cutting roller and that is adapted to be able, when the continuous strip is engaged between said first and second cutting rollers, to cooperate with the first helical blade to cut said continuous strip over all a width of said continuous strip from the first edge to the second edge,
• the drive device, the first cutting roller, and the second cutting roller being driven by at least one electric motor,
• a variable synchronizer controller in electrical communication with the at least one electric motor and configured to select and to modify a synchronization ratio between the rotation speed of the first cutting roller and the forward speed of the continuous strip in such a manner as to adjust a cutting angle at which a cut in the continuous strip is oriented relative to the longitudinal direction of said continuous strip, and
• wherein during a single cut of the continuous strip, the variable synchronizer controller employs at least one synchronization law that dynamically modifies the synchronization ratio while the first blade is engaged on the continuous strip, between the first edge and the second edge, so as successively to fix a plurality of synchronization ratios with different values.