Şükrü ÖZŞAHİN, Aydın DEMİR, İsmail AYDIN

Optimization of Veneer Drying Temperature for the Best Mechanical Properties of Plywood via Artificial Neural Network

The drying of veneer is an essential part of the veneer-producing process to aid the gluing during the manufacture of the plywood and laminated veneer lumber. Determining the optimum veneer drying temperature without decreasing of mechanical properties is also very important from industrial viewpoint. Due to the high drying costs, increased temperatures are being used commonly in plywood industry to reduce the overall drying time and increase capacity. However, high drying temperatures can alter some physical, mechanical and chemical characteristics of wood and cause some drying-related defects. In this study, it was aimed to predict the optimum drying temperature for alder and scots pine veneers via artificial neural network modelling for optimum mechanical properties. Therefore, mechanical strength values of plywood panels manufactured from alder and scots pine veneers were dried at temperatures of 110, 130, 150, 170, 190 and 210°C. Shear strength, bending strength and modulus of elasticity of the plywood panels were experimentally determined according to EN 314-1 and EN 310 standards. Then, the mechanical strength values based on veneer drying temperatures are subjected to prediction by artificial neural network modelling. As a results of this study, the optimum drying temperature values were obtained as 165, 162 and 161°C in Scots pine plywood and 190, 195 and 196°C in alder plywood, for best shear strength, bending strength and modulus of elasticity values, respectively.

Keywords:

Artificial Neural Network, Mechanical Properties Veneer Drying Temperature, Alder, Scots Pine,

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Aydin, I., (2014). Effects of veneer drying at high temperature and chemical treatments on equilibrium moisture content of plywood. Maderas. Ciencia y tecnología, 16(4), 445-452.
Aydin, I. & Colakoglu, G., (2008). Variations in bending strength and modulus of elasticity of spruce and alder plywood after steaming and high temperature drying. Mechanics of Advanced Materials and Structures, 15(5), 371-374.
Bekhta, P. & Salca, E.,A., (2018). Influence of veneer densification on the shear strength and temperature behavior inside the plywood during hot press. Construction and Building Materials, 162, 20-26.
Ceylan, I., (2008). Determination of Drying Characteristics of Timber by Using Artificial Neural Networks and Mathematical Models. Drying Technology, 26(12), 1469-1476.
Christiansen, A.,W., (1990). How overdrying wood reduces its bonding to phenol formaldehyde adhesives: a critical review of the literature, part I physical responses. Wood Fiber Sci., 22(4), 441–459.
Currier, R.,A., (1958). High Drying Temperatures- Do They Harm Veneer. Forest Products Journal, 8(4), 128-136.
Demirkir, C., Özsahin, Ş., Aydin I. & Colakoglu, G., (2013). Optimization of some panel manufacturing parameters for the best bonding strength of plywood. International Journal of Adhesion and Adhesives, 46, 14-20.
EN 310, (1993). Wood based panels. Determination of modulus of elasticity in bending and of bending strength. European Standard.
EN 314-1, (1998). Plywood–bonding quality–Part1: test methods, European Standard.
Esteban, L.,G., Fernandez, F.,G. & Palacios, P., (2011). Prediction of plywood bonding quality using an artificial neural network. Holzforschung, 65(2), 209–214.
Fernández, F.,G., Esteban, L.,G., Palacios, P., Navarro, N. & Conde, M. (2008). Prediction of standard particleboard mechanical properties utilizing an artificial neural network and subsequent comparison with a multivariate regression model. Investigación agraria: Sistemas y recursos forestales, 17(2), 178–187.
Industry News & Markets, (2018). Wood Products Prices in Europe. The International Tropical Timber Organization (ITTO) Tropical Timber Market Report, U.S.
Lehtinen, M., (1998). Effects of manufacturing temperatures on the properties of plywood. Helsinki University of Technology. Laboratory of Structural Engineering and Building Physics, TRT Report No 92, Finland.
Lehtinen, M., Syrjänen, T. & Koponen, S., (1997). Effect of Drying Temperature on Properties of Veneer. Helsinki University of Technology, Laboratory of Structural Engineering and Building Physics, Finland.
Ozsahin, S. & Aydin, I., (2014). Prediction of the optimum veneer drying temperature for good bonding in plywood manufacturing by means of artificial neural network. Wood science and technology, 48(1), 59-70.
Sernek, M., (2002). Comparative Analysis of Inactivated Wood Surfaces. Ph.D. Thesis, Faculty of the Virginia Polytechnic Institute and State University, Blacksburg, Virginia.
Shen, K.,C., (1958). The Effects of Dryer Temperature, Sapwood and Heartwood, and Time Elapsing Between Drying and Gluing on The Gluing Properties of Engelmann Spruce Veneer, MSc Thesis, Faculty of Forestry, The University of British Columbia.
Suchsland, O. & Stevens, R.,R., (1968). Gluability of Southern Pine Veneer Dried at High Temperatures, Forest Products Journal, 18(l), 38-42.
The Food and Agriculture Organization (FAO), (1990). Energy Conservation in the Mechanical Forest Industries: FAO Forestry Paper, Rome.
The Food and Agriculture Organization (FAO), (2018). FAOSTAT-FAO Statics Division - Production Quantity/Plywood. http://faostat3.fao.org/browse/F/FO/E.
Theppaya, T. and Prasertsan, S., (2004). Optimization of Rubber Wood Drying by Response Surface Method and Multiple Contour Plots. Drying Technology, 22(7), 1637-1660.