Even after sawing, planing, and finishing, some wood products still aren't ready to ship. Consider the sheets of wood made for siding homes and cladding other outdoor structures. Most of these boards have subtle but fairly consistent texturing. According to David Kaley of Omron Industrial Automation, Schaumburg, Ill., some lumber manufacturers that produce such siding have installed next-generation inspection sensors on motion arms to examine grain depths — and ensure that grains on the boards aren't too shallow or deep.
One such system at a Midwestern lumberyard uses lasers mounted on an X-Y gantry from PBC Linear of Rosco, Ill.; boards pass underneath while the inspection arm quickly zigzags over them. The lasers have robust sensor heads, so withstand the dirty, splintery lumberyard environment; speed and accuracy also prevent inspection bottlenecks.
A similar grading application on the East Coast uses cameras instead: Here, wood is automatically sorted by grades. More consistent planks and pieces are packaged for sale; those with pronounced variation are either packaged for lower-grade applications, or returned to the mill for further processing.
For more information on sensing, call Omron at (800) 556-6766 or visit omron247.com. For other articles on automation in pulp and paper industries, visit motionsystemdesign.com and search pulp.
