Many dimension lumber sawmills in Canada use productivity as a success indicator and are not willing to produce small quantities of specialty products for remanufacturing because of the adverse impact on overall production. This report examines the use of simulation tools to evaluate the impact of producing a mix of dimension lumber and specialty products for advance processing. The simulation tools estimate productivity changes resulting from diverting varying percentages of logs to higher valued, rough, green products. As present sawmill simulation tools are unable to consider defects other than wane, a number ofsimplifying assumptions were made regarding the proportion of logs suitable for higher valued products and the grade yields from these logs. When a relatively low percentage of logs were deemed suitable for non-standard sizes, and when the grade yields were assumed to be high, the impact on productivity was minimal. Productivity decreased with increasing percentages of logs from which higher valued products could be targeted, and also with decreasing grade yields.
Simulation tools, including Forintek’s log breakdown simulator, OptitekTM, are being developed that have the ability to utilize scan data that includes internal defects. This tool, when coupled with data provided by scanners using X-ray technology, will allow a more accurate evaluation of the impact on mill flow of diversifying the product mix.