Log yard management has a significant effect on plywood/LVL manufacturing, particularly in the aspects of log conditioning, veneer processing and product quality. At present, log conditioning is seldom optimized due mainly to the variation of species and log diameter, log storage time and seasonal climate changes. The key objectives of this work were to: 1) develop a new computer program to simulate how log temperature and conditioning time change with regard to log diameter sorting and conditioning parameters; and 2) determine the optimal log diameter sorting points in order to achieve the best log conditioning for peeling.
A new computer simulation program FPLogcon™ was successfully developed to simulate how log temperature and conditioning time change with regard to log diameter sorting and conditioning parameters in the plywood and LVL mills. Through computer simulation and two case studies, the benefits of log diameter sorting were successfully demonstrated and the log diameter sorting breakpoint was further optimized.
For spruce in mill A, compared to no diameter sorting (control), the optimum diameter sorting could result in about 28.8% reduction in heating time, and about 17.5% increase in equivalent log volume within the target temperature range.
For lodgepole pine in mill B, in the summer, compared to no diameter sorting (control), the optimum log diameter sorting breakpoint was 9-in, resulting in about 15% reduction in equivalent heating time (no change in equivalent log volume). In the winter, the optimum log diameter sorting point was 8-in, leading to about 4.5% increase in equivalent heating time along with an 11.6% increase in equivalent log volume within the target temperature range.
For plywood/LVL mills, specific benefits of log diameter sorting will include increasing the uniformity of log temperature distribution and thus veneer quality, and reducing heating time and thus energy consumption, increasing lathe efficiency, and reducing downtime and spin-out rate during peeling. Mill results will be collected to validate the benefits of optimum log diameter sorting in the new fiscal year.