INFLUENCE OF THERMAL MODIFICATION OF ASH WOOD (Fraxinus excelsior L.) AND MACHINING PARAMETERS IN CNC FACE MILLING ON SURFACE ROUGHNESS USING RESPONSE SURFACE METHODOLOGY (RSM)

Yıl 2020, Cilt: 11 Sayı: 2, 231 - 241, 01.06.2020

Vladislav Zdravkovıć Tanja Palıja Zoran Karadolamovıc

Öz

The objective of this research was to analyse the effect of thermal modification of ash wood (Fraxinus excelsior L.) at moderate temperature of 160oC and three processing parameters: spindle speed, feed rate and depth of cut in CNC face milling operation on surface quality, expressed by arithmetic surface roughness parameter (Ra).
In order to determine material properties, moisture content (MC), density, swelling, anti-swelling efficiency (ASE) and contact angle for both untreated and thermo-treated ash wood have been measured.
Highly effective, incomplete 33 Box-Behnken factorial design was made, with three levels of cutting speed: 8.000, 12.000, and 16.000 rpm; three levels of feed rate: 1.000, 1.500 and 2.000 mm/min; and three levels of depth of cut: 2, 4, and 6 mm. According to the above design matrix, all groups of 50x50x30mm samples have been machined with two machining strategies: raster and offset. Surface roughness parameter Ra was measured per each run. Response - surface analysis (RSM) was applied to the parameter Ra for all sets of samples. The 3-D response surface plots, polynomial equations and ANOVA tables have been obtained per each observed input variable, for both machining strategies (raster and offset).
The results indicated that the thermal modification of ash wood at 160 oC improved it`s physical properties: decreased MC, improved wood density, improved ASE and increased wood hydrophobicity.
Polynomial equations and ANOVA tables showed different behaviour of untreated and treated ash wood regarding changing of machining parameters in experimental space. Offset processing strategy, gave better results in the quality of wood surface, than raster processing strategy for all types of samples. Thermal modification of ash wood at 160oC improved surface quality after machining for both processing strategies

Anahtar Kelimeler

Ash wood, thermo-wood, surface roughness, response surface methodology (RSM), design of experiment (DOE), CNC face milling

Kaynakça

• [1] Akyildiz, M.H.; Ates, S., (2008). Effect of heat treatment on equilibrium moisture content (EMC) of some wood species in Turkey, Research J. Agric. Biol. Sci. 4 (6): 660-665.
• [2] Boonstra M., Rijsdijk J.F., Sander C., Kegel E., Tjeerdsma B., Militz H., Van Acker J., Stevens M. (2006). Microstructural and physical aspects of heat treated wood. Part 2: Hardwoods, Maderas, Ciencia y Tecnología 8: 209-217.
• [3] Box G.E.P., Behnken D.W. (1960). Some New Three Level Designs for the Study of Quantitative Variables., Technometrics, november, Vol. 2, No 4.
• [4] Cao, Y.; Lu, J.; Huang, R., (2012). Increased dimensional stability of Chinese fir through steam-heat treatment, Eur. J. Wood Prod., 70: 441- 444.
• [5] Dong-Hee Lee, Kwang-Jae Kim (2011). A Review on Posterior and Interactive Solution Selection Methods to Multiresponse Surface Optimization, Journal of Quality Vol. 18, No. 4.
• [6] Hazır E., Hüseyin Koç K. (2016). Optimization of wood surface machining parameters in CNC routers: Response surface methodology (RSM) approach, International Journal of Scientific Research Engineering &Technology, ISSN 2278-0882 Volume 5, Issue 10.
• [7] Hazır E., Hüseyin Koç K. (2016). Determination of wood cutting parameters using taguchi method, International Journal of Scientific Research Engineering & Technology, ISSN 2278-0882 Volume 5, Issue 11.
• [8] Herrera R., Krystofiak T., Labidi J., Llano-Ponte R. (2016): Characterization of thermally modified wood at different industrial conditions, Drewno Vol. 59, No. 197.
• [9] Islam S., Hamdan S., Rusop M., Rahman R., Saleh A., Idrus M., (2012). Dimensional Stability and Water Repellent affiency Measurement of Chemically Modified Tropical Light Hardwood, BioResources 7(1), 1221-1231.
• [10] ISO 4287:1997 Geometrical Product Specifications (Gps)– Surface Texture: Profile Method — Terms, Definitions and Surface Texture Parameters.
• [11] Karagoz U., Akyildiz M.H., Isleyen O. (2011). Effect of heat treatment on surfaceroughness of thermal wood machined by CNC, Pro Ligno 7(4): 50-58.
• [12] Kamdem, D.; Pizzi, A.; Jermannaud, A., (2002). Durability of heat-treated wood, Holz Roh-Werkst., 60: 1-6.
• [13] Kotilainen R. (2000): Chemical Changes in wood during heating at 150-260ºC, Ph.D. Thesis, Jyväskylä University, Finland.
• [14] Lovrić A., Zdravković V., Popadić R., Milić G., (2017). Properties of Plywood Boards Composed of Thermally Modified and Non-modified Poplar Veneer: BioResources12(4), 8581-8594.
• [15] Myers, R. H. and Montgomery, D. C., (1995), Response Surface Methodology: Process and Product Optimization Using Designed Experiments, 2nd Edition, John Wiley and Sons, New York.
• [16] Palija, T., Jaić M., Džinčić I., (2018): The Impact of Sanding System on the Surface Roughness of Medium Density Fibreboard, International Forest Products Congress -ORENKO 2018, Trabzon, Turkey, pp. 310-316.
• [17] Rawangwong S., Chatthong J., Rodjananugoon J. (2011). The study of proper conditions in face coconut wood by CNC milling machine, International Conference on quality and reliability (ICQR), Bangkok, pp. 455-459.
• [18] Rawangwong S., Chatthong J., Rodjananugoon J., Boonchouytan W. (2011). A Study of Proper Conditions in Face Milling Palmyra Palm Wood by Computer Numerical Controlled Milling Machine, Faculty of Engineering, Rajamangala University of Technology Srivijaya, Songkhla, Thailand, Silpakorn U Science & Tech J Vol. 5(2): 33-39.
• [19] Rosset P., Perre P., Girard P. (2004): Modification of mass transfer properties in poplar wood (P. Robusta) by a termal treatment at high temperature, Holz Roh-Werkst 62: 113-119.
• [20] Sofuoglu S.D. (2015). Using Artificial Neural Networks to Model the Surface Roughness of Massive Wooden Edge-Glued Panels Made of Scotch Pine (Pinus sylvestris L.) in a Machining Process with Computer Numerical Control, BioResources 10(4): 6797-6808.
• [21] Sofuoglu S.D. (2015). Determination of Optimal Machining Parameters of Massive Wooden Edge-Glued Panels Made of European larch (Larix decidua Mill.) using Taguchi Design Method, BioResources 10(4): 7772-7781.
• [22] Tjeerdsma, B. F.; Militz, H., (2005). Chemical changes in hydrothermal treated wood: FTIR analysis of combined hydrothermal and dry heat-treated wood, Holz Roh- Werkst 63: 102-11.
• [23] Uddin M.S., Ibaraki S., Matsubara A., Nishida S., Kakino Y. (2007): A Tool Path Modification Approach to Cutting Engagement Regulation for the Improvement of Machining Accuracy in 2D Milling With a Straight End Mill, Journal of Manufacturing Science and Engineering, 129(6): 1069.
• [24] Yildiz, S., (2002). Physical, mechanical, technological and chemical properties of beech and spruce wood treated by heating, PhD dissertation, Karadeniz Tech. Univ., Trabzon, Turkey.
• [25] Zdravković, (1999), Model of peeled veneer quality prediction by some elements of theory of reliability, PhD Thesys, Faculty of Forestry of Belgrade University.
• [26] Zdravković, V.; Lovrić, A., 2010: Influence of thermal treatments on wettability and water spread on the surface of poplar veneer, Paper presented at First Serbian Forestry Congress, held on 11-13 November, Faculty of Forestry, University of Belgrade.
• [27] Zdravković V., Lovrić A., Stanković B., (2013): Dimensional Stability of Plywood Panels Made from Thermaly Modified Poplar Veneers in the Conditions of Variable Air Humidity. Drvna Industrija 64 (3).