Improving lumber yield using a dual system

Rough mills embody the process of cutting up kiln-dried lumber to components used by discrete wood products manufacturers to manufacture products like furniture, kitchen cabinets, flooring, or other items. Rough mills traditionally have either ripped the lumber first (e.g., the lumber is first cut into strips lengthwise) then cut the strips to the required part lengths or they crosscut the lumber first to part lengths (e.g., cutting the lumber to shorter, full width segments) then ripped the segments to the required part widths. Both processes offer advantages and disadvantages and, depending on the input lumber geometry (e.g., size) and the cutting bill requirements (e.g., the size of the resulting components) may result in higher yield for individual cases. Using ROMI 4.1, a rough mill simulator that simulates real-world rough mills and can combine rip and chop operations, this study investigated the potential benefits from using such a dual system. Findings suggest that cutting bills requiring small parts when cutting from lower quality lumber produce better yield when a rip-first approach is used, while cutting bills asking for wide and long parts perform better when material is chopped first. However, in every case, yield can still be improved when the decision to rip or to chop first is made on each individual board.