Advance methods determining both the quality of raw material and its dimensions were undertaken for a long time and they are still common research subjects. However, despite that since this day, no technology has been developed in a way allowing to perform these activities in a manner equal or better than human visual assessment. Examples of currently used optimization systems are MiCROTEC, LuxScan, WoodTech, LMI. These methods work on the basis of the defect’s identification, their admissibility in various dimensional and quality functions of prefabricated products. The assessment of the defects images for all the sawn pieces of timber (four-sided scanning system for sawn timber is presented in Fig. 1) allows the identification of the intensity of undesirable features.
Studies have shown that knots were the largest groups of identified defects reducing the raw material quality. This conclusion confirmed that the knots constitute up to 75% of all defects affecting the qualitative and dimensional classification of coniferous sawn timber (Duchateau et. all. 2013). The amount of knots and their condition have a major effect on the strength properties of wood such as modulus of elasticity. The known correlation between the modulus of elasticity and the strength allows to determine the technical value of wood from Poland (Krzosek 2009; Roszyk 2016). The aim of the undertaken research was to confirm the hypothesis that the number and the frequency of knots affect the technical parameters of sawn materials.
Keywords: dimensional assessment, knots, modulus of elasticity, sawn timber
Authors
A. Trociński
M. Wieruszewski
J. Kawalerczyk
J. Siuda
R. Mirski
Login to download the PDF