Optimization of edging and trimming operations for red oak lumber

This research project investigated the upgrading of edging and trimming operations for red oak lumber through computer-aided optimization. The main objective was to evaluate how lumber value recovered by actual hardwood operations compare with the maximum value obtainable through the optimization of edging and trimming.

An optimization procedure was developed involving the use of an iterative computer program for finding optimum edging and trimming solutions. The hardwood lumber grading program developed by Klinkhachorn et.al. [1988] was incorporated into the procedure. Comparison of results with actual values indicated that only 63% to 80%, approximately, of the maximum theoretical value was obtained in the sawmills studied.

Edging and trimming optimizing systems equipped with scanners that provide only wane information have been successfully applied in softwood lumber manufacturing. The second part of this study investigated the lumber value recovery that can be expected if a similar system were applied to hardwood edging and trimming, i.e., if optimization were based only on wane input. Based on the output of a computer optimization program that maximizes volume yield subject to wane limitations, it was found that for red oak boards, an average value of approximately 80% of the optimum can be recovered through the application of this procedure.