Patent ID: 6893520

Claim:
A method for minimizing scrap in a gapless order change for a corrugator, said corrugator including a slitter-scorer operable to provide longitudinal slit lines and score lines in a continuous corrugated paperboard web passing through the slitter-scorer, the slit lines dividing the web into a plurality of output webs of selected widths, a pair of vertically separated cut-off knives downstream of the slitter-scorer for receiving and cutting the output webs into selected sheet lengths, said knives including an upper knife and a lower knife, and a web selector device between the slitter-scorer and the cut-off knives for selectively separating the output webs along a common innermost slit line into an upper output web portion and a lower output web portion for said respective upper knife and lower knife, said method comprising the steps of: (1) determining an order change location in the web defining the transition from a running order to a new order of a selected one of the upper and lower output web portions; (2) partially severing the web upstream of the web selector device to provide a generally transverse slit at the order change location to subsequently connect the common innermost slit line of the running order web portions and the common innermost slit line of the new order output web portions; (3) adjusting the slitter-scorer in an order change region of the web that includes the order change location to terminate the running order slit and score lines and to begin the new order slit and score lines; (4) after separating the output web portions, sensing a transverse edge of a web portion defined by said transverse slit and generating an edge location signal; and, (5) operating one of the cut-off knives in response to said transverse edge location signal to cut one of the web portions on the line of said transverse slit.