NIR imaging checks OSB mix

Manufacturers of oriented strand board (OSB) must ensure that the proper quantity of resin is mixed with wood and correctly distributed.

Manufacturers of oriented strand board (OSB) must ensure that the proper quantity of resin is mixed with wood and correctly distributed. By using a near-infrared (NIR) spectrograph and image-processing software, researchers at the Fraunhofer Institute for Wood Research WKI (Braunschweig, Germany; www.wki.fraunhofer.de) and the Reutlingen Research Institute (Reutlingen, Germany; www.esb-research.org) are helping manufacturers to distribute the expensive resin as efficiently as possible.

In the production of OSB, the strands of wood are mixed with resin and scattered in several layers to form a mat, which is then fed into a press on an endless conveyor. These boards are produced under high pressure and temperature. WKI project manager Burkhard Plinke says the new technique will enable continuous measurements during production. A line spectrograph scans the surface of the shavings mat before it enters the press, recording the image of a narrow section across the entire width of the forming line. The spectrograph registers the light in the NIR range. At these wavelengths, the resin can be distinguished from the wood.

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