Evaluating log stiffness using acoustic technology for manufacturing structural oriented strand board

Abstract

Wood has a wide range of properties that vary by species, within species, and even within a tree. It is used for many kinds of applications from paper to decorative items to high strength construction materials. This creates a need to be able to monitor wood quality, especially for certain markets like construction where the end product is used in structural applications. Due to an increased demand for wood, most of the logs purchased by oriented strand board (OSB) and other engineered wood companies are low quality tops and young trees with low stiffness mixed with higher quality logs. Common practices are to visually grade logs as they enter a manufacturing site, followed by mechanical testing of the finished product after processing. Since these methods are expensive, produce waste, and result in reduced productivity, non-destructive evaluation (NDE) techniques using acoustics have been adopted in the veneer and sawmill industries to improve quality control but so far are not common in the engineered wood industries. The overall goal of this project was to determine if the log quality affects the final product and if acoustic NDE technology is a satisfactory tool for determining log stiffness prior to entering the manufacturing process. It was found that low stiffness logs produced panels with low stiffness while high and medium stiffness logs produced panel with similar properties. The HM 200 was a satisfactory tool for determining log stiffness. Further studies need to be done to determine how to incorporate NDE tools into the manufacturing process.