Lumber Complex of the Future–Part V: Log Processing

The hardwood sawmill industry of today continues to reflect both the highly specialized nature of hardwood lumber manufacturing and the general lack of automated processing systems. A typical large hardwood sawmill of today would have a production capacity of 50 to 60 MBF/ shift. In many of these mills, the logs are tree length (up to 50 feet long). A multichannel, drag chain log deck feeds the logs to the mill. Logs are unscrambled at the deck by a knuckle boom loader. A circular cutoff saw with remote control stops for length selection is used to cut the tree-length logs into shorter logs required for the carriage. The logs are diverted to one of two major breakdown points: the chipper-canter or the circular headsaw. The conventional hardwood headrig is a circular headsaw and side-dogging carriage. Circular headsaws outnumber band headsaws in hardwood mills by 2:1. After initial breakdown, cants from both the chipper-canter and the headsaw are processed on the double-arbor edger. A portion of the lumber produced by the double-arbor edger and chipper-canter, and especially by the headsaw, must be edged. The typical three-saw edger of the past is being replaced in many large hardwood mills by chipping edgers. The edged lumber converges just before the trim-saws. Automatic sorters are used in large hardwood mills; a typical type is the drop sorter.

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