The Influence of Cutting Speed on Concordant and Discordant Tangential Milling of MDF

Mechanics, Materials Science & Engineering, September 2016

ISSN 2412-5954

The Influence of Cutting Speed on Concordant and Discordant Tangential Milling of MDF Priscila Roel de Deus 1, Manoel Cleber de Sampaio Alves 2, Luciano Rossi Bilesky 1 1 2 DOI 10.13140/RG.2.1.2114.3286

Keywords: roughening, panels, wood, MDF.

ABSTRACT. The tangential milling is consistent when the direction of forward movement is equivalent to the movement of the cutter. But the dissenting milling is when the sense of forward movement is contrary to movement of the cutter.

The way the material is removed differentiates and may cause different results in apereza the surface. For Medium Density Fiberboard - MDF material and which is composed of pressed lignocellulosic fibers with resin and presence of heat, concordant and discordant response to milling with diferetntes surfaces presents results. The objective of this study was to analyze the milling results in consistent direction and discordant through the MDF surface analysis with the average roughness parameter (R and discordant direction with six repetitions in each direction. The tests were carried out with four cutting speed in the forward speed of 2 m/min and 1 mm machining depths. The results of surface roughness in the cutting speeds in concordant direction are larger by 50% than in the discordant direction.

Introduction. MDF (Medium Density Fiberboard) is an industrial product manufactured from lignocellulosic fibers and resin through the joint action of heat and pressure. It is a material used in the furniture industry, since it presents homogeneity, dimensional stability and mechanical strength next to medium density solid wood. It also receives various types of coating, maintaining the quality, besides reacting positively to machining processes.

The growth in demand for industrial wooden products and their derivatives is clear, due to this fact, the research of technological innovations is necessary. With this technology, the industry is able to offer state-of-art products while increasing the competitiveness in the market. Machining stands out among these innovations, once it evolves notably and there are machines that provide the automation of processes within wood sector, producing higher quality machined workpieces.

The MDF machining in Computer Numerical Control (CNC) centers represents technology that combines materials, machines and tools, which results in more accurate and with quality finishes workpieces.

The cutting parameters are numerical quantities related to the movement of the tool and workpiece during milling, such activities must be suited to each material both tool and workpiece. From these parameters, it is possible to make use of the milling process as a form of productivity and quality improvement.

Understanding the machining forces is primordial for the determination of the cutting conditions, machine and tool lifespan and the workpiece quality [1]. Also cites the importance of machining because it determines the quality of the workpiece and tool wear [2].

The use of a suitable machining technique for the transformation of wood can minimize or even correct problems due to its variability [3].

The literature for the most appropriate cutting parameters in order to optimize processes, reduce costs, and increase utilization of the workpiece, tool and machine. The experiment studied the influence of MMSE Journal. Open Access www.mmse.xyz

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Mechanics, Materials Science & Engineering, September 2016

ISSN 2412-5954

machining depth (63 mm) and cutting speed (396 m/min) in cutting force and tangential milling with carbide. The results showed that the depth of cut and cutting speed significantly influence the cutting strength, tool lifespan, and particularly the costs [4].

In a studied the influence of the cutting speed and feed rate parameters through MDF surface roughness. The surface roughness decreases as the cutting speed increases. The MDF milling shows the advantage of using a high cutting speed [5].

Highlighting the importance of high quality surface in machining, as it can influence the cost of the final product in the industry, particularly for high durability materials. Thus, milling operations are almost indispensable, consuming much of the processes time and affecting significantly on the quality of the surface finish and final product costs. The surface roughness is influenced by the cutting speed, cutting depth, tool and workpiece conditions [6]. The same investigation, the surface roughness decreases as the number of revolutions increases, along with the reduction of the machining depth [6].

The high surface quality can be achieved by the proper selection of cutting parameters [7]. The influence of the cutting forces and their required intensity for wood milling reported [8]. The cutting parameters that influence the surface quality must be understood as every specific need, mainly related to wood [9].

In a study the values of MDF artificial finishing through the peripheral milling process with the feed rate of 2,90; 4,10; 5,80; 8,20; 10,90; 15,15; 21,80 and 30,30 m/min and the section thicknesses of 1, 3 and 5 mm in concordant and discordant direction. The roughness values are lower in consistent direction [10].

In [11] conducted measuring the feed force in chipboard panels, which is commonly used in the furniture industry. The surface characteristics are strongly influenced by machining parameters. Feed rate values near to 2 m/min and cutting speed near to 800 m/min have proved more suitable for finishing, benefiting more effectively the furniture industry.

The concordant milling occurs when the direction of the forward movement is equivalent to the mill movement. The discordant milling consists in the direction of forward movement being contrary to the mill movement [11].

In [9] studied the concordant and discordant milling in CNC machining center with solid carbide tool.

The result of the average roughness - Ra shows statistically significant differences for the two cutting directions. It is concluded that discordant direction provided the lowest roughness but with high power consumption.

The objective of this study is to investigate the influence of cutting speed on concordant and discordant tangential milling of MDF through the average and overall roughness.

Material and Method. Commercial medium density fiberboard MDF by Duratex was used, with average basic density of 736.22 kg/m3, average moisture of 8.33%, 15 mm thickness and coated plate.

Tangential milling tests were performed on a machining center with Computerized Numerical Control (CNC) TECH Z1 model by SCM brand. The mill used was a solid carbide cutter top finishing type with three-helix cutting teeth, HWM- Premium - Upcut Spiral Bit model.

The MDF specimens, dimensions of 300x65x15 mm, were milled tangentially on concordant and discordant direction with six repetitions in each one. The tests were carried out with four cutting speed in the feed rate of 2 m/min and 1 mm machining depth.

For the measurement of workpieces average roughness represented by the average roughness parameter (Ra), a rugosimeter Taylor Hobson 25sultronic model was used including measuring probe with diamond conemeasures emphasized the average roughness parameter ( MMSE Journal. Open Access www.mmse.xyz

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Results and discussion. In the concordant direction, the average roughness values (Ra) of 1.0 mm in depth were analyzed by Tukey test and result in a coefficient of variation of 16,38%. The feed rate does not differ significantly with FVa = 1,47; p-value >5%, as well as the relation between cutting speed and feed rate with FVcxVa = 1,93; p-value >5%. However, among the cutting speeds occur statistical differences (FVc = 13,34; p-value >5%).

It is shown the results of the average roughness (Ra) according to the machining in concordant direction with 1 mm machining depth. In Fig. 1 is illustrated the results regarding the average roughness (Ra).

Average Roughness (Ra) 30

Roughness Ra (

)

25

20

4000 rpm 8000 rpm

15

12000 rpm 16000 rpm

10 a

a

a

a

b ab a

a

b

ab a

a

5 2 m/min

4 m/min

6 m/min

Feed rate

Fig. 1. Values of average roughness Ra for 1 mm machining depth regarding to cutting speed and feed rate in concordant tangential milling.

It is noted that the cutting speed 804 m/min (16000 rpm) is related to lower average surface roughness lues were

inferior to those found for panels such as MDF. During a peripheral cylindrical milling with vertical These results highlight the satisfactory outcome for MDF surface finishing in CNC milling [10].

During MDF tangential milling and feed rate of 4 m/min, observed the average surface roughness In discordant direction, the average roughness (Ra) values with 1.0 mm depth and tangential milling were analyzed through Tukey test and result in a coefficient of variation of 16.46%. The feed rate has significant differences with FVa = 6.94; p-value >5%. The relationship between cutting speed and feed rate with FVcxVa = 0,72; p-value >5% and cutting speed with FVc = 0,59; p-value >5%, do not present significant statistical differences. For total roughness (Rt) and 1,0 mm depth, it is observed a coefficient of variation of 21.10%. There were no statistical differences between feed rates (FVa = 1.23; p-value >5%) and in the relationship of cutting speed and feed rate with FVcxVa = 0,5; p-value >5%. In the cutting speed, there were no significant statistical differences (FVc = 3,62; p-value >5%).

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Mechanics, Materials Science & Engineering, September 2016

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In Fig. 2, it is observed that in all feed rates do not occur statistically significant differences and the lowest roughness values occur in the feed rate of 2 m/min. It is observed a tendency of lower roughness values occur in the cutting speed 12000 rpm and 8000 rpm (603 and 201 m/min).

Roughness Ra (

)

Average Roughness (Ra) 23 21 19 17 15 13 11 9 7 5

4000 rpm 8000 rpm 12000 rpm

a a a a

a a a a

b ab a ab

2 m/min

4 m/min

6 m/min

16000 rpm

Feed Rate

Fig. 2. Values of average roughness Ra for 1 mm machining depth regarding to cutting speed and feed rate in discordant tangential milling.

Fig. 2 shows the feed rate of 2 m/min with the lowest surface roughness values. Only with feed rate of 6 m/min that is observed difference in cutting speed of 201 m/min. The lowest roughness values g of Eucalyptus sp in discordant direction for feed rate of 3 m/min and cutting speed of 292 m/min, [14].During discordant milling and feed speed of 5 m/min with cutting speed of 504 m/min showed

the MDF. During discordant tangential CNC milling in MDF with feed rate of 8 m/min, was found that using F, noted that with feed rate of 3 m/min and cutting speed of 527 m/min, the average roughness was approximately 10 discordant direction [5].

Summary. In conclusion, the parameter that most influenced the surface quality was the cutting speed. All tests demonstrated that the cutting speeds of 603 and 804 m/min, i.e. the higher cutting speeds used in the experiments, correspond to lower values of roughness.

The dissenting tangential milling corresponds to the lower roughness values, showing up to 50% lower results than the concordant tangential milling.

References alta velocidade de corte. 2010. 87f Dissertation (Master in Mechanical Engineering) Faculty of Engineering, State University Paulista, Ilha Solteira, 2010.

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Dissertation (Master in Mechanical Engineering and Materials Technology). Federal Center of Technological Education Celso Suckow da Fonseca CEFET / RJ. Rio de Janeiro RJ. 2012.

[3] Zamarian, E. H. C.; Alburquerque, C. E.; Matos, J. L. M. Usinagem Da Madeira De Bracatinga - 638, Jul./Set. 2012. do corte no fresamento de faceamento. CONEM [5] Davim, J. P. Clemente, V. C. Silva, S. Surface Roughness Aspects In Milling MDF (Medium Density Fiberboard). Int J Adv Manuf Technol. 40:49 55. 2009.

[6] Chen, Chih-Chern; Liu, Nun-Ming; Chiang, Ko-Ta; Chen, Hua-Lun. 2012. Experimental Investigation Of Tool Vibration And Surface Roughness In The Precision End-Milling Process Using The Singular Spectrum Analysis. Int J Adv Manuf Technol. 63:797 815. 2012.

[7] Kiswanto, G. Zariatina, D.L. Ko, T.J. The effect of spindle speed, feed-rate and machining time to thesurface roughness and burr formation of Aluminum Alloy 1100 in micro-milling operation.

Journal of Manufacturing Processes. JMP-243; 16p. 2014. cutting process. Journal of Materials Processing Technology 148: 220 225. 2004.

[9] Pinheiro, C. Efeitos do teor de umidade da madeira no fresamento de Pinus elliottii. 2014. 122f.

UNESP - Univ. alves, M. T. T. Estudo do acabamento superficial em chapas MDF usinadas em processo de fresamento. MADEIRA: arquitetura e engenharia, ano 3, n.8, 2002.

[11] Valarmathi, T. N.; Palanikumar, K.; Latha, B. Measurement and analysis of thrust force in drilling of particle board (PB) composite panels. Measurement 46: p 1220 1230. 2013.

[12] Diniz, A. E.; Marcondes, F. C.; Coppini, N. L. Tecnologia da Usinagem dos Materiais. 8. ed. icial y potencia de corte en el cepillado de acacia 28, 2011. l -476. 2014.

[15] Camilo, R. S. Fresamento de Eucalyptus grandis. Work Completion of course (Graduation) Industrial Engineering wood, Universidade Estadual Paulista, Campus Experimental Itapeva, Itapeva, 2013. 105 p.

- MDF. 2013. 76 f. Work Completion of course (Graduation) - Industrial Engineering wood, Universidade Estadual Paulista, Campus Experimental Itapeva, Itapeva, 2013.

Cite the paper Priscila Roel de Deus, Manoel Cleber de Sampaio Alves & Luciano Rossi Bilesky (2016). The Influence of Cutting Speed on Concordant and Discordant Tangential Milling of MDF. Mechanics, Materials Science & Engineering Vol.6, doi: 10.13140/RG.2.1.2114.3286

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