Resource-Efficient And Data-driven integrated log and board Strength grading
Coordinator: Olof Broman, Luleå University of Technology, Sweden
olof.broman (at) ltu.se
Other partners: AT, DE
Project duration: 01/2019-03/2022
Efficient raw material use of wood and building with wood are fundamental components of Europe’s strategy to take steps towards a sustainable bio-based economy, and both require optimised strength grading procedures.
In order to improve the current production processes in the sawmill industry, the strength quality assessment needs to start before the logs are sawn. Pre-sorting of logs for strength has the potential to improve significantly raw material utilization, e.g. by adapted sawing patterns. The project READiStrength aimed to improve the current concepts for strength grading of sawn timber products by integrating log-level assessments into the strength grading process.
Three different scanning techniques were tested: 3D optical scanning of the outer log shape, discrete X-ray scanning of logs and computed tomography (CT) log scanning. Results showed that optical scanning had limited potential to predict the strength of the sawn timber products. Discrete X-ray scanning enabled significantly better prediction of sawn timber strength than optical scanning. CT scanning, with its high level of detail, had the highest potential for predicting the strength of the sawn wood product. Combining cheaper solutions such as optical or discrete X-ray scanning with acoustic log measurements also provided improved results for pre-sorting timber.
Overall, the results show that log pre-sorting can significantly reduce raw material consumption when producing strength-graded timber. Correctly done and driven by the appropriate data (see above), log pre-sorting can be used to control and even improve the timber strength properties. The studies also showed opportunities to reconcile log pre-sorting with the requirements for machine strength grading according to the current standard EN 14081-2.
Project website: link
Project presentation at ForestValue kick-off seminar 23-24 May 2019: pdf
READiStrength publication – “Big Data” in der Festigkeitssortierung, full article in German here, English summary available in ResearchGate.