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Roughness study on homogeneous layer panels manufactured from treated wood waste/Estudo da rugosidade em paineis de camada homogenea fabricados com residuos de madeira tratada.

Introduction

Kollmann, Kuenzi, and Stamm (1975), Maloney (1977) and American National Standards Institute A208.1 (ANSI, 1999) report that particleboard definition depends on particles types, board structure, resin and manufacture equipment. A wide sizes and shapes variety of raw materials and particles may be used.

Particleboard is manufactured from lignocellulosic materials (usually wood) with synthetic resin or other suitable resin and glued together under heat and pressure in a hot press. Others materials may be added during manufacture in order to improve certain properties. The standard Associacao Brasileira de Normas Tecnicas NBR 14810 (ABNT, 2013) defines medium density particleboard, with density between 551 and 750 kg m-3, a panel manufactured from wood particles bonded with thermosetting synthetic resin, which are consolidated under action together of heat and pressure.

Wood-based panels have been widely used around the world in various segments of the timber industry. Thus, alternative raw materials, as various types of agro-industrial wastes, have been investigated like studies by (Ashori & Nourbakhsh, 2008; Girods et al., 2009; Guler, Copur, & Tascioglu, 2008; Fiorelli, Rocco Lahr, Nascimento, Savastano Junior, & Rossignolo, 2011; Fiorelli et al., 2012).

The standard Associacao Brasileira de Normas Tecnicas NBR ISO 4287 (ABNT, 2002) defines surface roughness and geometric parameters used in determining the roughness. The obtained profile parameter was the arithmetic mean deviation of the assessed profile, defined as Ra and expressed in microns (um), according to the standard Associacao Brasileira de Normas Tecnicas NBR ISO 4287 (ABNT, 2002). Ra is the main parameter of the surface roughness profile.

By the importance of the roughness analyses in particleboards, this study proposed homogeneous particleboard (PPH) manufactured evaluation from different densities and reutilizing treated wood waste to evaluate roughness after circular saw cuttings, it is important to study the roughness of the panels in the end of introduction

Material and methods

Shavings from Eucalyptus sp. and Pinus sp. treated wood were classified as shown in Figure 1. The greater shavings dimension was 2.8 mm. The shavings were mixed with two resins: urea formaldehyde and castor oil based polyurethane. Panels were made with nominal thickness of 10 mm with nominal dimensions of 400 X 400 mm and densities of 0.6, 0.8 and 1.0 g cm-3. In mixer supplies were homogenized and, at continuation, a mold received mixture which was transferred to hot press (Figures 1 and 2).

Cutting methodology

Panels cutting methodology included as basis Brazilian standard Associacao Brasileira de Normas Tecnicas NBR 6162 (ABNT, 1989). Circular saws used are described in Table 1; PPHs cutting speed was 58.98 m [min.sup.-1]., and forward speed per tooth in saws were Z48 = 0.35 mm; Z96 = 0.17 mm; Z108 = 1.55 mm. From Table 1, TS is the Saw type; D is the Saw diameter, Z is the Sooth number and TD is the Tooth types and angle.

Cutting number consisted of 2040 strips (Figure 3), in different densities and resin utilized. Cutting were randomly selected and divided into groups of Pinus sp., Eucalyptus sp. and resins urea formaldehyde and castor oil based polyurethane. From selection was measured roughness with Taylor Robsow Surtronic equipment.

Roughness testing

Mean roughness is defined as absolute values arithmetic mean of removal ordered (yi), of roughness profile points in relation to mean line, within measurement pathway (lm). Specimens for this analysis presented 350 mm in length, with a width ranging from 100 to 120 mm. Roughness testings were performed at University of Sao Paulo State, Unesp, Itapeva Campus, as illustrated in Figure 4.

In Table 3 are described roughness values according to Brazilian standard Associacao Brasileira de Normas Tecnicas NBR 8404 (ABNT, 1984), which were used as results comparison parameters.

Statistical analysis

Factors and experimental levels investigated in obtaining cutting roughness values [Ra (pm)] of homogeneous particleboard manufactured were Wood Species [Specie], varying between Pinus (Pinus) and Eucalyptus (Euca.), and adhesive type [Adhes.], consisting of castor oil based polyurethane resin (PU) and urea formaldehyde (UF). Two levels of two factors combination resulted in a full factorial design with four treatments (Tr), clarified in Table 4.

For each of four experimental treatments delineated were manufactured 8 homogeneous particleboards, being removed two samples from each panel, in a total of 64 specimens tested in roughness cutting values (Ra) obtaining.

In order to investigate isolated factors effect [Specie; Adhes.] and interaction between them [Specie x Adhes] on cutting roughness values was used variance analysis (ANOVA), considered at 5% significance level (a). Equivalency between treatment means was considered as null hypothesis (H0), and no equivalence between means (at least two treatments) as alternative hypothesis Hi). By ANOVA formulation, evaluated by Minitab[R] software version 14, P-value lower than significance level (P-value < 0.05) implies to reject null hypothesis (at least one treatments mean differs from the others), accepting it in otherwise (the treatments means are equivalent). To validate Anova were tested normality in cutting roughness values distribution, with help of Anderson-Darling test (AD), variance homogeneity with Bartlett (Bt) and Levene (Le) tests and waste independence by means of waste versus order graph.

Accused significance of isolated factors on cutting roughness values, in sequence was used multiple comparison Tukey test (contrast test between means) enabling to group factor significant levels. From Tukey test, A indicates highest mean group, B is the second highest mean group and so on, same letters implied treatments with equivalent means. In case of significant interaction between factors, interaction between factors graphic was used as an auxiliary way to interpret interaction effects.

Results and discussion

Table 5 shows mean values, variation coefficients (CV) along with smaller (Min.) and with bigger (Max.) roughness values related to fabricated panels according four delineated experimental treatments.

Rolleri and Roffael (2010) studied the surface roughness of particleboards produced from wood particles and urea formaldehyde resin and obtained Ra roughness values in the range of 5.2 to 11.2 [micro]m. Their roughness results are similar to this study.

Tabarsa, Arshorie, and Gholamzadeh (2011) evaluated the roughness of particleboard made with sugarcane bagasse and urea formaldehyde resin and found roughness Ra of between 10 and 25 pm. The roughness results reported by these authors are superiors to those found in this study.

Varanda, Alves, Goncalves, and Santiago (2010) evaluated the roughness of Eucalyptus grandis wood pieces submitted to sanding and found an average roughness value of 7.4 pm, after sanding. The results of Varanda et al. (2010) are similar to the results of this study roughness.

Statistical analysis positive results obtained were demonstrated. Figure 5 shows cutting roughness mean values graph from four experimental treatments investigated.

Figure 6 presents Anova tests validation results on cutting roughness values. By means of P-values (> 0.05) found for both tests, cutting roughness values have normal distribution, variances homogeneity and waste independence, validating Anova model.

Table 6 shows Anova results on panel cutting roughnesses values, where DF represents freedom degrees, Seq SS squares sum, Adj SS the set squares sum, Adj MS set mean square and F Fisher's statistics.

As observed in Table 6, the two individual factors were significant on panels cutting roughness values, same did not occur with the interaction between them, considered not significant by Anova. Table 7 presents tukey's test results of two factors considered significant, where x is the mean and Ag. groups formed.

From tukey's test results in Table 6, regarding wood species, Eucalyptus provided the greatest cutting roughness values, and with respect to adhesive, urea formaldehyde showed superior behavior compared to castor base polyurethane resin. Figure 7 shows graphs of the two factors main effects considered significant on the cutting roughness values.

Conclusion

Results obtained of this research allow concluding that:

--individual factors Specie and Adhesive were significant on roughness values of particleboards. The interaction between factors was considered not significant by Anova;

--particleboards produced with Pinus sp. particles presented roughness values (5.67 [micro]m) lower than particleboards produced with Eucalyptus sp. particles (6.33 [micro]m);

--particleboards produced with castor oil base polyurethane resin presented roughness values (5.59 [micro]m) lower than particleboards produced with urea-formaldehyde resin (6.42 [micro]m);

--Particleboards produced with urea-formaldehyde resin showed worse surface finish (Ra roughness greater value), still showed environmental problems in the use of this formaldehyde-based resin;

--roughness values of panels manufactured according to four experimental treatments delineated showed roughness class N 10, with roughness values (Ra) of less than 12.5 microns, according to Associacao Brasileira de Normas Tecnicas NBR 8404 (ABNT, 1984).

Doi: 10.4025/actascitechnol.v39i1.29438

Acknowledgements

Gratitude to Support Foundation for Research (Fapesp) and Stuctural Engineering Department (SET/EESC/USP) and Wood and Timber Structures Laboratory (LaMEM--EESC/USP).

References

Associacao Brasileira de Normas Tecnicas [ABNT]. (1984). NBR 8404. Indicacao do estado de superficies em desenhos tecnicos. Rio de Janeiro, RJ: Associacao Brasileira de Normas Tecnicas.

Associacao Brasileira de Normas Tecnicas [ABNT]. (2013). NBR 14810. Paineis de particulas de media densidade. Rio de Janeiro, RJ: Associacao Brasileira de Normas Tecnicas.

Associacao Brasileira de Normas Tecnicas [ABNT]. (1989). NBR 6162. Movimentos e relacoes geometricas na usinagem dos metais. Rio de Janeiro, RJ: Associacao Brasileira de Normas Tecnicas.

Associacao Brasileira de Normas Tecnicas [ABNT]. (2002). NBR ISO 4287. Especificacoes geometricas do produto (GPS)--Rugosidade: Metodo do perfil. Termos, definicoes e parametros. Rio de Janeiro, RJ: Associacao Brasileira de Normas Tecnicas.

American National Standards Institute [ANSI]. (1999). A208.1. Standard for particleboard. Gaithersburg, US: American National Standards Institute.

Ashori, A., & Nourbakhsh, A. (2008). Effect of press cycle time and resin content on physical and mechanical properties of particleboard panels made from the underutilized low-quality raw materials. Industrial Crops and Products, 28(2), 225-230.

Fiorelli, J., Curtolo, D. D., Barrero, N. G., Savastano Junior, H., Pallone, E. M. J. A., & Johnson, R. (2012). Particulate composite based on coconut fiber and castor oil polyurethane adhesive: An eco-efficient product. Industrial Crops and Products, 40, 69-75.

Fiorelli, J., Rocco Lahr, F. A., Nascimento, M. F., Savastano Junior, H., & Rossignolo, J. A. (2011). Paineis de particulas a base de bagaco de cana e resina de mamona: producao e propriedades. Acta Scientiarum.Technology, 33(4), 401-406.

Girods, P., Dufour, A., Fierro, V., Rogaume, Y., Rogaume, C., Zoulalian, A., & Celzard, A. (2009). Activated carbons prepared from wood particleboard wastes: Characterization and phenol adsorption capacities. Journal of Hazardous Materials, 166(1), 491-501.

Guler, C., Copur, Y., & Tascioglu, C. (2008). The manufacture of particleboards using mixture of peanut hull (Arachis hypoqaea L.) and European Black pine (Pinus nigra Arnold) wood chips. Bioresource Technology, 99(8), 2893-2897.

Kollmann, F. P.; Kuenzi, E. W.; & Stamm, A. J. (1975). Principles of wood science and technology: wood based materials (Vol. 2). New York, US: Springer-Verlag.

Maloney, T. M. (1977). Modern particleboard & dry-process fiberboard manufacturing. San Francisco, US: Miller Freeman Publications.

Rolleri, A., & Roffael, E. (2010). Influence of the surface roughness of particleboards and their performance towards coating. Ciencia Y Tecnologia, 12(2), 143-148.

Tabarsa, T., Ashori, A., & Gholamzadeh, M. (2011). Evaluation of surface roughness and mechanical properties of particleboards panels made from bagasse. Composites: Part B, 42(5), 1330-1335.

Varanda, L. D., Alves, M. C. S., Goncalves, M. T. T., & Santiago, L. F. F. (2010). A influencia das variaveis do lixamento tubular na qualidade de pecas de Eucalyptus grandis. Cerne, 16(supl.), 23-32.

Received on October 9, 2015.

Accepted on May 11, 2016.

License information: This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Maria Fatima do Nascimento (1), Andre Luis Christoforo (2) *, Juliano Fiorelli (3), Luciano Donizeti Varanda (4), Laurenn Borges de Macedo (4) and Francisco Antonio Rocco Lahr (5)

(1) Laboratorio de Madeiras e Estruturas de Madeira, Escola de Engenharia de Sao Carlos, Universidade de Sao Paulo, Sao Carlos, Sao Paulo, Brazil. (2) Departamento de Engenharia Civil, Universidade Federal de Sao Carlos, Rod. Washington Luis, Km 235, s/n, 13565-905, Jardim Guanabara, Sao Carlos, Sao Paulo, Brazil. (3) Departamento de Engenharia de Biosistemas, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de Sao Paulo, Pirassununga, Sao Paulo, Brazil. (4) Departmento de Engenharia de Materiais, Escola de Engenharia de Sao Carlos, Universidade de Sao Paulo, Sao Carlos, Sao Paulo, Brazil. (5) Departamento de Engenharia de Estruturas, Escola de Engenharia de Sao Carlos, Universidade de Sao Paulo, Sao Carlos, Sao Paulo, Brazil. * Author for correspondence. E-mail: christoforoal@yahoo.com.br

Caption: Figure 1. Shavings classification.

Caption: Figure 2. Mold, mattress and hot press.

Caption: Figure 3. Strips cutting.

Caption: Figure 4. Rugosimeter device to verify roughness of PHPM.

Caption: Figure 5. Cutting roughness mean values of manufactured panels. Tr1--Pinus wood and PU adhesive; Tr2--Pinus wood and UF adhesive; Tr3--Eucalyptus wood and PU adhesive; Tr4--Eucalyptus wood and UF adhesive.

Caption: Figure 7. Graphs of Main effects on roughness values: wood species (a) and adhesive type (b).
Table 1: Circular saws for wear testing.

TS                  D     Z     TD

Wide circular saw   350   96    RT
                    350   48    ED
                    350   108   RT

Table 3. Roughness reference values in accordance with
Brazilian standard Associacao Brasileira de Normas Tecnicas NBR
8404 (ABNT, 1984).

Roughness class   Roughness Ra ([micro]m)

N12                         50
N11                         25
N10                        12.5
N09                         6.3
N08                         3.2
N07                         1.6
N06                         0.8
N05                         0.4
N04                         0.2
N03                         0.1
N02                         005
N01                        0.025

Table 4. Experimental treatments delineated in homogeneous
particleboard manufacturing.

                  Specie               Adhesive

Treatments (Tr)   Pinus   Eucalyptus    PU     UF

Tr1                 X                    X
Tr2                 X                          X
Tr3                           X          X
Tr4                           X                X

Table 5. Results obtained from cutting roughness from fabricated
panels according four delineated experimental treatments.

                                         Min.
Treatments   Ra ([micro]m)   CV (%)   ([micro]m)   Max. ([micro]m)

Tr1              5.20        14.66       3.80           6.40
Tr2              6.15        13.94       4.80           7.53
Tr3              5.98        17.14       4.20           8.80
Tr4              6.68        20.50       4.53           9.73

Table 6. Anova results on the cutting roughnesses values.

Source            DF   Seq SS   Adj SS   Adj MS   F-value   P-value

Specie            1    6.910    6.910    6.910     6.51      0.013
Adhes.            1    10.898   10.898   10.898    10.27     0.002
Specie x Adhes.   1    0.277    0.277    0.277     0.26      0.611
Error             60   63.644   63.644   1.061
Total             63   81.730

Table 7: Tukey's test results on panels cutting roughness values.

                          Specie               Adhesive

Stat.                     Pinus   Eucalyptus    PU     UF

Ra ([micro]m) - [bar.x]   5.67       6.33      5.59   6.42
Ag.                         B         A         B      A

Figure 6. Anova validation test results of cutting roughness
values: normality test (a), variance homogeneity test (b) and waste
independence (c).

a

Mean              6.002
StDev             1.139
N                 64
AD                0.395
P-Value           0.363

b

Bartlett's Test

Test Statistic    5.94
P-Value           0.114

Levene's Test

Test Statistic    1.65
P-Value           0.188
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Author:do Nascimento, Maria Fatima; Christoforo, Andre Luis; Fiorelli, Juliano; Varanda, Luciano Donizeti;
Publication:Acta Scientiarum. Technology (UEM)
Article Type:Ensayo
Date:Jan 1, 2017
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