Nondestructive evaluation of honeycomb and surface checks in red oak lumber

Honeycomb and closed surface checks are types of lumber drying defects that can go undetected and result in considerable losses during further processing of the lumber into high-quality products. This paper summarizes the results of an experiment that investigated the use of ultrasonic nondestructive evaluation (NDE) techniques to detect honeycomb and surface checks in red oak lumber. Dried 1-1/4-inch- (30-mm-) thick red oak specimens were analyzed using ultrasonic through transmission NDE. A strong relationship was observed between the occurrence of honeycomb and surface checks and excessively long sound transmission times. Hence, this technique shows strong promise to detect honeycomb and surface checks in lumber