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Abstract
Researchers have hypothesized that segmented processing of cutting orders may result in reduced yield compared to batch processing. This study simulated application of both the batch and segmented processing systems for a crosscut-first rough mill with manually operated saws. The processing of three cutting orders of increasing relative difficulty was simulated. Simulated yield results comparing segmented to batch processing systems showed significantly higher yields for the batch processing system for moderate and difficult cutting bills. Cutting bill difficulty reduced yield significantly more for the segmented compared to batch processing system. The batch processing system provided higher yields for the higher, more valuable lumber grades. No significant difference in the number of cutting operations between batch and segmented processing was detected.
The expense and complexity of actual rough mill studies have led researchers to develop rough mill computer simulations to model the rough mill lumber cut-up process. These simulations allow control of the variables that influence yield that are not possible to control in an actual rough mill production situation (Wiedenbeck et al. 1994). Researchers and managers have used the simulations to manipulate the important variables to determine their influence on yield and productivity.
Nearly all furniture production rough mills cut interior and exterior dimension parts to order rather than to stock. The parts typically are components of various sizes required for a single product or a related group of products. For this reason, only limited numbers of each part size are required and the needed quantities of each part size differ.
Rough mill managers assign parts to be cut by individual machines to fulfill the requirements of each cutting order. In a crosscut-first rough mill, in which both crosscut saws and straight-line ripsaws are manually operated, only a limited number of parts are assigned to each machine (Wylie 1954).
The limitation on the number of parts cut at each machine is imposed by the physical requirements of the machines and the limitations on the decision-making capacity of the operators. For example, no more than five part lengths are usually assigned to be cut simultaneously on a manually operated crosscut saw. Operators must attempt to determine the best combination of part lengths to most effectively utilize the available lumber length or to utilize the...