THE EFFECT OF THE FOCAL LENGTH POSITION OF THE FOCUSING LENS ON THE DISCOLORATION ROUGHNESS OF PLYWOOD UNDER DIFFERENT CO2 LASER ENGRAVING MODES

Zhivko Gochev; Pavlin Vitchev

Authors

Zhivko Gochev University of Forestry, Sofia, Bulgaria
Pavlin Vitchev University of Forestry, Sofia, Bulgaria

Keywords:

CO2 laser engraving; birch wood; plywood; roughness of surfaces.

Abstract

The results of a surface roughness study obtained by CO2 laser engraving of birch plywood specimens are presented in the paper. A ZnSe lens with focal length F = 50.8 mm; focal position ∆F = -4, -6, and -8 mm above the material surface; laser beam power P = 4.0, 5.6, and 7.2 W; laser beam scanning speed vf = 250, 260, and 270 mm/s was used for the research. The roughness of the treated surfaces was measured with an electronic profilometer, model Surftest SJ-210 (Mitutoyo – Japan).

The experimental results were evaluated via the parameters Ra, Rq, and Rz and analyzed using specialized software Q-StatLab, ANOVA analysis, and interaction diagrams of all parameters, and relevant conclusions and recommendations were made.

The analyses indicate that the surfaces of birch plywood treated with a CO2 laser exhibit higher roughness than untreated ones, with a deviation of 2 to 4 times greater for the Ra parameter and 2.2 to 3.9 times greater for the Rz parameter. The primary reason for the difference in surface roughness of CO2 laser-treated materials at different focusing positions on the surface is the varying laser beam power density. A higher beam power density leads to more significant absorbed heat, resulting in increased surface roughen.

References

Batov, I., Gotchev, Zh., Dinkov, B., Janic, Z., 1997, Study on the head field and the structural changes during the interactions between CO2 laser beam and wood material, The 3rd International Conference on the Development of Forestry and Wood Science/Technology, Volume II, Belgrade, pp. 560-568, ISBN 86-7299-048-x.

BDS EN ISO 4287:2006. Geometrical product specifications (GPS) - Surface texture: Profile method - Terms, definitions and surface texture parameters (ISO 4287:1997).

Dinkov, B., Gochev, Zh., Barnekov, V., 1996. Optimization of the Influence of the Main Notch Formation Factors in Laser Beam Interaction with Wood and Wood Materials, Proceedings of the International Scientific Conference „Mechanical Technology of Wood”, 21-23 November 1996, Sofia, University of Forestry Publishing House, pp. 305-311 (in Bulgarian).

Eltawahni, H., Rossini, N., Dassisti, M., Alrashed, K., Aldaham ,T., Benyounis, K., Olabi, A., 2013. Evaluation and optimization of laser cutting parameters for plywood materials. Opt. Lasers Eng., 51(9):1029-1043, ISSN: 0143-8166. https://doi.org/10.1016/j.optlaseng.2013.02.019

Gotchev, J., Barnekov, V., Dinkov, B., 1994. Modeling the Laser Cutting of Particleboard, 2nd International Conference on Automated Lumber Processing Systems and Laser Machining of Wood and Composites, Michigan State University, East Lansing, Michigan, USA, pp. 71-81.

Gochev, Zh., 1996. Investigation of the process of laser cutting of furniture parts made of particle board, PhD Thesis, University of Forestry, Sofia, p. 200 (in Bulgarian).

Gochev, Zh., Dinkov B., 1996. Specific Cutting Energy at Laser Beam Interaction with Wood and Wood Materials, Proceedings of International Scientific Conference, University of Forestry, Section: Mechanical Technology of Wood, Sofia, pp. 298-304 (in Bulgarian).

Gochev, Zh., 2016. Laser wood cutting and modification in its structure, IInd International Furniture Congress: proceedings of papers, 13-15 October, Muğla Sitki Koçman University Faculty of Technology Department of Wood Product Industrial Engineering, Turkey, pp. 210-215.

Gochev, Zh., Vichev P., 2022. Color modifications in plywood by different mode of CO2 laser engraving, Scientific journal Acta Facultatis Xylologiae, Zvolen, 64(2), pp. 77-86, ISSN 1336-3824. https://doi.org/10.17423/afx.2022.64.2.08

Gochev, Zh., 2023. Real Parameters of a Focused CO2 Laser Beam and its Determination when Using Lenses with Different Focal Lengths, 32nd International Conference on Wood Science and Technology – ICWST 2023, Unleashing the Potential of Wood-Based Materials, proceeding of papers, 7-8 December, Zagreb, pp. 67-74, ISBN 978-953-292-083-3.

Gurau, L., A. Petru, A. Varodi, M. Timar, 2017. The Influence of CO2 Laser Beam Power Output and Scanning Speed on Surface Roughness and Colour Changes of Beech BioResources 12(4):7395-7412, ISSN: 1930-2126. https://doi.org/10.15376/biores.12.4.7395-7412

Hernández-Castañeda, J., H. Kursad, L. Li, 2011. The effect of moisture content in fibre laser cutting of pine wood. Opt. Lasers Eng., 49(9-10):1139–1152, ISSN: 0143-8166, https://doi.org/10.1016/j.optlaseng.2011.05.008

Jurek, M., R. Wagnerová, 2021. Laser beam calibration for wood surface colour treatment, European Journal of Wood and Wood Products, 79(5):1097–1107, ISSN: 1436736X. https://doi.org/10.1007/s00107-021-01704-3

Kalimanova, I., D. Teodosiev, D. Diakov, H. Nikolova, 2012. Study of the influence of the glass-carbon coating on the micro-topografy of the articulating surfaces of ceramic implants, Proceedings of the XXII National Scientific Symposium with „Metrology and Metrological Assurance 2012“, September 10-14, 2012, Sozopol, Bulgaria, pp. 147-153, ISSN: 1313-9126 (in Bulgarian).

Kovács, B., Sipos, S., Czifra, Á., 2012. Interpretation of „Rz = 4×Ra“ and other roughness parameters in the evaluation of machined surfaces, ICT-2012, In Proceedings of the 13th International Conference on Tools 27-28 March 2012, Miskolc, Hungary, pp. 237-242, ISBN: 978-963-9988-35-4.

Kubovský, I., Babiak, M., Cipka, Š., 2012. A determination of specific wood mass remowal energy in machining by CO2 laser, Acta Facultatis Xylologiae Zvolen, 54(2): 31−37, 2012, Zvolen, Technická univerzita vo Zvolene, ISSN: 13363824.

Kúdela, J., Kubovský, I., Andrejko, M., 2022. Influence of Irradiation Parameters on Structure and Properties of Oak Wood Surface Engraved with a CO2 Laser, Materials, Vol. 15, Iss. 23, p. 21, ISSN: 1996-1944, https://doi.org/10.3390/ma15238384

Kúdela, J., Andrejko, M., Kubovský, I., 2023. The Effect of CO2 Laser Engraving on the Surface Structure and Properties of Spruce Wood, Coatings, Vol. 13, Iss. 12, p. 17, ISSN: 2079-6412 https://doi.org/10.3390/coatings13122006

Li, R. C. He, W. Xu, X. Wang, 2022. Prediction of Surface Roughness of CO2 Laser Modified PoplarWood Via Response Surface Methodology. Maderas. Ciencia y Tecnología 2022, Vol. 24, pp. 1-12, on-line ISSN: 0718-221X, https://doi.org/10.4067/s0718-221x2022000100442.

Martinez-Conde, A., T. Krenke, S. Frybort, U. Müller, 2017. Review: Comparative analysis of CO2 laser and conventional sawing for cutting of lumber and wood-based materials. Wood Sci. Technol., 51: 943–966, ISSN: 1432-5225. https://doi.org/10. 1007/s00226-017-0914-9

Orech, J., Jůza, F., 1987. Měrná energie úběru a její určení při interakci laserového záření se dřevem [Specific removal energy and its determination during the interaction of laser radiation with wood]. Drevársky výskum, Vol. 114, pp. 29-40, ISSN: 0012-6136.

Pagano, N., Genna, S., Leone, C., Lopresto, V., 2009. Wood Laser machining using CO2 30W laser in CW and pulse regime, In book: Innovative production machines and systems. LAPT, Napoli, pp. 145-150, ISBN-10:1849950067.

Petutschnigg, A., M. Stöckler, F. Steinwendner, J. Schnepps, H. Gütler, J. Blinzer, H. Holzer, Th. Schnabel1, 2013. Laser Treatment of Wood Surfaces for Ski Cores: An Experimental Parameter Study, Advances in Materials Science and Engineering, Volume 2013(11), Article ID 123085, pp 1-7, ISSN: 1687-8434 (Print), ISSN: 1687-8442 (Online), https://doi.org/10.1155/2013/123085

Sikora, A., F. Kačík, M. Gaff, V. Vondrová, T. Bubeníková, I. Kubovský, 2018. Impact of thermal modification on color and chemical changes of spruce and oak wood, Journal of Wood Science, Volume 64, pp. 406-416. https://doi.org/10.1007/s10086-018-1721-0

Vuchkov, I., Stoyanov, S., 1986. Mathematical modeling and optimization of technological objects, SPH Tehnika, Sofia, p. 341 (in Bulgarian).

Vidholdová, Z., Reinprecht, L., Igaz, R., 2017. The Impact of Laser Surface Modification of Beech Wood on its Color and Occurrence of Molds, 12(2):7395-7412, ISSN: 1930-2126 http://doi.org/10.15376/biores.12.2.4177-4186

https://wikibgbg.top/wiki/Inkscape; https://paradacreativa.es/bg/que-es-inkscape-y-como-funciona/.

https://www.productionmachining.com/articles/the-difference-between-ra-and-rz.