Paul Boughton
When manufacturing chipboard it is important to distribute the resin on the wood shavings correctly. Researchers are now developing a measuring technique that makes it possible to monitor the application of the resin during production.
In OSB (oriented strand board), a product in which flakes of a defined size are used, the wood flakes are mixed with resin and scattered in several layers to form a mat, which is then fed into a press on a conveyor. The boards are produced under conditions of high pressure and temperature.
Manufacturers of OSB have to ensure the mixture is right; if they use too little resin, or if the resin is not distributed properly on the strands, the resulting boards are not strong enough. But the resin is expensive and accounts for roughly one-third of the production costs, so using too much resin is a waste of money.
Researchers at the Fraunhofer Institute for Wood Research (WKI) and their colleagues at the Reutlingen Research Institute (RRI) are helping manufacturers to distribute the resin as efficiently as possible. WKI project manager Burkhard Plinke states: "We use special optics to measure how well the resin is distributed." At present, manufacturers add expensive dyes to the resin and then check how it spreads inside the board. However, this method requires random samples to be inspected, whereas the new technique will enable continuous measurements during production. A line spectrograph (a camera with special integrated optics) scans the surface of the shavings mat before it enters the press, recording an image of a narrow section across the entire width of the forming line. The optics registers the light in the near-infrared range, which enables the resin to be distinguished from the wood. Plinke says: "A computer stores the data and analyses them online before the mat is transported into the press. The data indicate where the strands are glued and where they are not."
Thanks to the new technique, manufacturers of OSB will soon be able to monitor the distribution of the glue online and quickly detect any unevenness. This will help them to save costs and to further optimise their production processes. The researchers will be presenting the measuring principle at the Ligna trade fair in Hanover, Germany, from 18-22 May 2009 (Hall 27, Stand J35).
For more information, visit www.fraunhofer.de
In OSB (oriented strand board), a product in which flakes of a defined size are used, the wood flakes are mixed with resin and scattered in several layers to form a mat, which is then fed into a press on a conveyor. The boards are produced under conditions of high pressure and temperature.
Manufacturers of OSB have to ensure the mixture is right; if they use too little resin, or if the resin is not distributed properly on the strands, the resulting boards are not strong enough. But the resin is expensive and accounts for roughly one-third of the production costs, so using too much resin is a waste of money.
Researchers at the Fraunhofer Institute for Wood Research (WKI) and their colleagues at the Reutlingen Research Institute (RRI) are helping manufacturers to distribute the resin as efficiently as possible. WKI project manager Burkhard Plinke states: "We use special optics to measure how well the resin is distributed." At present, manufacturers add expensive dyes to the resin and then check how it spreads inside the board. However, this method requires random samples to be inspected, whereas the new technique will enable continuous measurements during production. A line spectrograph (a camera with special integrated optics) scans the surface of the shavings mat before it enters the press, recording an image of a narrow section across the entire width of the forming line. The optics registers the light in the near-infrared range, which enables the resin to be distinguished from the wood. Plinke says: "A computer stores the data and analyses them online before the mat is transported into the press. The data indicate where the strands are glued and where they are not."
Thanks to the new technique, manufacturers of OSB will soon be able to monitor the distribution of the glue online and quickly detect any unevenness. This will help them to save costs and to further optimise their production processes. The researchers will be presenting the measuring principle at the Ligna trade fair in Hanover, Germany, from 18-22 May 2009 (Hall 27, Stand J35).
For more information, visit www.fraunhofer.de
