Edge-glued Panels Research Articles

Clustering of tropical species through multivariate analysis of the bonding properties of edge-glued panels (EGP)

Tropical woods have high added value, and the use of waste for panel production is an initiative to add more value to this material, typically consisting of various species. The use of raw materials from tropical solid wood waste in the Amazon region contributes to the reduction of carbon emissions associated with the burning of this material. In this context, this study aimed to cluster species based on the bonding properties of Amazonian woods by applying multivariate analysis. The apparent density 12% and strength of finger joint and edge-glued joints of Cedrela odorata, Enterolobium schomburgkii, Erisma uncinatum and Qualea paraensis was evaluated which were joined in homogeneous and hybrid configurations with the adhesives PVA and EPI, as spreading rate of 180 g/m2. The treatments were compared by multivariate analysis of variance and discriminant analysis. The discrimination of species and combinations based on wood density (low, medium, and high) revealed that this is the most important characteristic for grouping different species that make up tropical hardwood waste for the production of EGP panels. In practice, the separation of species into groups according to wood densities can contribute to a better definition of the indications for use of edge glued panels of each density class, and assertive targeting for applications according to the strength ranges required. In the static bending, parallel tensile and shear tests all species and their combinations met the minimum requirements normative, indicating the approval of species and combinations studied for the production of EGP panels.

Evaluation of conventional and microwave drying of tropical Amazonian wood indicated for the manufacture of EGP (Edge Glued Panels)

Evaluation of conventional and microwave drying of tropical Amazonian wood indicated for the manufacture of EGP (Edge Glued Panels)

Determination of Optimal Drilling Parameters of Massive Wooden Edge Glued Panels (EGP) and Medium Density Fiberboard using Taguchi Design Method

In this paper, the optimization of computer numerical control (CNC) drilling parameters was conducted using the Taguchi design method on the drilling holes’ inner surfaces roughness (Ra) massive wooden edge-glued panels (EGP) made of spruce (Picea Orientalis Link.), beech (Fagus Orientalis Lipsky), Iroko (Chlorophora excelsa) and Medium Density Fiberboard surfaced with synthetic resin sheet (MDFlam). Three drilling parameters and their effects on Ra were evaluated. These parameters included spindle speed, feed rate, and cutter type. Surface roughness measurements according to ISO 4287 were performed on the inner surfaces of the holes, and Ra values were obtained. An analysis of variance (ANOVA) was performed to identify the significant factors affecting the Ra. Optimum drilling parameter combinations were acquired by analyzing the signal-to-noise (S/N) ratio. It is shown that the most ideal result was obtained with a two flutes cutter (cutter number 2) at 18000 rpm and feed of 1750 mm/minute for in-hole roughness values of the MDFlam test sample. In the drilling operations performed with a double-entry cutter, the lowest roughness values were obtained in all materials.

Evaluation of the potential use of Amazonian palm species for the production of edge-glued panels

ABSTRACT The potential of Attalea maripa and Attalea speciosa was evaluated for the production of edge-glued panels. The chemical and physical properties and the quality of the bonding of the species and mixed treatment between them, under different conditions, were evaluated. The length bonding was performed with polyvinyl acetate (PVA) adhesive and the side with PVA and emulsion polymer isocyanate (EPI) in two spreading rates. The species A. maripa has a lower content of extractives in cold and hot water, total extractives, ash and pH, and higher density compared to A. speciosa. The tangential, radial and volumetric shrinkage and shrinkage anisotropy of the species were statistically equal. On the length bonding, only in the tensile test after drying pre-treatment were the requirements of the technical standards not met. As regards side bonding, the treatments of A. maripa and mixed joints with EPI reached the standard for the pre-treatment in cold water.

Physical-mechanical characterization of Amazonian woods by non-destructive methodology for the manufacture of EGP (Edge Glued Panel) panels

Studies of the technological properties of little-known native species are essential for an indication of sustainable management of the Amazon. The study aimed to evaluate the physical-mechanical performance of five Amazonian species obtained from an area managed in the Amazon by a non-destructive methodology, and to indicate their use to manufacture EGP panels. The samples were obtained from non-flooded secondary forest in the Amazon/Brazil (EEST/INPA). Fifteen trees were selected to determine the physical-mechanical properties, using the microwave system to determine the moisture, the apparent density test and the dynamic modulus of elasticity (MOEd). The microwave system presents better drying performance when compared to the conventional method (artificial drying), considering that the dry woods in this system present greater stability in the equilibrium moisture, and the woods from Murici, Breu vermelho and Angelim pedra presented content close to 12%, ideal moisture for EGP manufactures. The apparent density of the woods varied from 0.76 to 1.18 g.cm-3, classified as high density, following the standards of tropical woods. The studied woods presented MOEd of 11,175 to 14,109 MPa, thus demonstrating good resistance, and lower risk of deformation for the different uses, including for EGP panels, whether structural or not, being necessary to consider the type of adhesive. The quality of the studied woods presents a promising result for industrial indication, since they are mostly unknown or non-commercial woods, where technological characterization is a key tool to assist in decision making in the forest management plans that may indicate the use of new species in the forestry sector.

Bonding quality of two lesser-used wood species Brachystegia spiciformis and Julbernardia globiflora from Mozambique

The objective of this study was to evaluate the density, chemical properties and bonding quality of two lesser-used Mozambican wood species known as messassas (Brachystegia spiciformis and Julbernardia globiflora) aiming at edge-glued panel production. The bonding was performed using structural adhesive polyvinyl acetate D4, semi-structural adhesive emulsion polymer isocyanate and non-structural polyvinyl acetate D3 applied at 120·m-2 and 180·m-2 weights. Density, chemistry, edge shear bonding, wood failure percentage and the finger-joint tests were performed in accordance with ISO 13061-2:2014 (E), TAPPI, EN 13354:2008, ABNT-NBR ISO 12466-1:2006 and ASTM 5572:2005 standards, respectively. The results showed that both species have medium density, high extractives and lignin contents typical of tropical wood. The emulsion polymer isocyanate adhesive was approved with better performance compared to polyvinyl acetate D3 and D4 adhesives. It can also be affirmed that Brachystegia spiciformis and Julbernardia globiflora have similar bonding behaviour and the potential for producing edge glued panel panels, especially for indoor use

Qualidade das juntas coladas de madeira de cinco espécies de Eucalyptus com adesivos acetato de polivinila e resorcina-formaldeído

O objetivo deste trabalho foi avaliar o potencial das madeiras de Eucalyptus benthamii, Eucalyptus dunnii, Eucalyptus grandis, Eucalyptus saligna e Eucalyptus urophylla, para produção de painéis colados lateralmente (EGP) e madeira laminada colada (MLC). As propriedades físicas e químicas das madeiras foram determinadas com base nas normas COPANT 461/459:1972 e TAPPI 204/252:2002. Foram confeccionadas juntas coladas com adesivo acetato de polivinila (PVA), com gramaturas de 150 g m-2 e 200 g m-2, e resorcina-formaldeído (RF), com 200 g m-2 e 300 g m-2. A qualidade de colagem foi avaliada por meio de ensaios de cisalhamento, com base na norma EN 13354:2008. Todas as espécies apresentaram densidade básica de média a baixa e anisotropia de contração de média a alta. O teor de extrativos totais e pH estão dentro da faixa referenciada na literatura. As avaliações dos resultados com base nos requisitos da norma EN 15353:2008 para 5º percentil inferior indicaram que as espécies E. benthamii, E. dunnii, E. grandis e E. saligna, apresentam potencial para produção de painéis EGP com adesivo PVA, para o uso interno, e externo com cobertura. Para a colagem com adesivo RF, o E. dunni apresentou melhores resultados, sendo indicativo do seu bom potencial para a produção de madeira laminada colada, visando aplicações estruturais em ambientes interno úmido e externo. Para os dois tipos de adesivos o aumento na gramatura não afetou os resultados de cisalhamento das juntas coladas.

Aceptación y confianza de Bitcoin en México: una investigación empírica

El Bitcoin forma parte de las llamadas criptomonedas y puede definirse como un sistema de pagos electrónico público y descentralizado universal, basado en la tecnología de Blockchain. El problema que enfrenta es la confianza en su uso; por lo tanto, el objetivo de la presente investigación es analizar los factores que influyen la adopción y uso de Bitcoin en México. Para ello, se utiliza el modelo UTAUT2 integrado con la variable de confianza. El modelo fue probado empíricamente mediante la aplicación de una encuesta de 106 cuestionarios, bajo el método de mínimos cuadrados parciales, con modelos de ecuaciones estructurales (PLS-SEM). Los principales resultados indican que la expectativa de rendimiento, la motivación hedonista, el hábito y su descentralización, son los principales factores que influyen en la confianza para la adopción y uso de Bitcoin. Los resultados ilustran a las empresas y cualquier interesado sobre las ventajas del uso de Bitcoin.

EFFECT OF THE HEAT TREATMENT OF Hovenia dulcis Thunb. WOOD ON THE PRODUCTION OF EGP PANELS WITH DIFFERENT ADHESIVES

The objective of this work was to analyze the shear strength of edge-glued panels (EGP) made from the H. dulcis Thunb. wood thermally modified by the VAP HolzSysteme® process. Initially, the Hovenia dulcis samples were heat-annealed by the VAP HolzSysteme® process, and then bonded with Resorcinol-formaldehyde (RF), Melamine-urea-formaldehyde (MUF), Isocyanate Polymer Emulsion (EPI) and Polyvinylacetate (PVAc) and submited to pre-treatments for dry, humid and external environment and without pre-treatment to evaluate the shear strength, 5th percentile and failure in the wood. It was observed a decrease in the shear strength of the thermorrectified H. dulcis wood for all adhesives. All adhesives obtained results superior to the minimum required by the standard EN13354 (2009) for the wood without pre-treatment as for the wood without thermoregulation as well as for the heat treated wood, and may be used for non-structural purposes. However, for the external environment (three cycles) only the MUF adhesive obtained value that meets the minimum standards of the standard, in this way, it is suggested to glue the EGP of H. dulcis without thermortification and with thermorrectification using the MUF adhesive, which has achieved better performance offering greater resistance in dry, wet and external environments.

Production of edge-glued panels with wood from three Brazilian dry forest tree species and five types of adhesives

ABSTRACTThis article evaluated the technical viability of producing edge-glued panels (EGPs) with wood from three Brazilian dry forest species and five adhesives. Experimental design was completely randomized, involving 3 wood species, 5 adhesives and 5 replicates, totalizing 75 observations. Test specimens were separated into groups, each one submitted to a different experimental condition or after a pretreatment: dry condition; moist condition; after 6-hour boil test; after a boil cycle test. Glueline performance indicators were the 5th lower percentile and the percentage of wood failure. The three wood species showed good potential for EGPs and two adhesives were able to withstand the 6-hour boil test and the boil cycle test. Despite a negative correlation between extractives content and 5th lower percentile was observed, when the adhesive melamine-urea-formaldehyde (MUF) was used, this detrimental effect was overcome and all the joints reached the minimum strength required by the technical standards.

Production of Joints Of Eucalyptus Sp. to Obtain Edge Glued Panels

ABSTRACT This research aimed at evaluating the quality of bonded joints of Eucalyptus wood by using different faces and adhesives to produce EGP (Edge Glued Panels). Glue line shear specimens were obtained from bonded joints glued with PVAc (Polyvinyl Acetate) and EPI (Emulsion Polymer Isocyanate) adhesives, using pieces oriented with tangential, radial and intermediary faces, as well as the combination between them. The specimens were submitted to two pretreatments in order to simulate the use of joints in dry and wet environments. For shear tests, 12 treatments were obtained. The results indicated that the use of tangential x tangential and tangential x intermediary bonding faces and EPI adhesive presented better glue line shear strength for EGP in dry and wet pretreatments, respectively. The joints bonded in the radial x radial direction presented statistically inferior values when compared to the other treatments.

THE USE OF Eucalyptus camaldulensis AND Eucalyptus urophylla WOOD IN THE PRODUCTION OF EDGE GLUED PANELS

This study aimed to evaluate the shear strength of bonded wood joints of Eucalyptus camaldulensis and Eucalyptus urophylla with vinyl polyacetate (PVA) and isocianate polymeric emulsion (EPI) adhesives with the amount of glue of 150 and 180 g/m². The specimens were submitted to shear tests in dry and wet conditions, based on the procedure described in standard EN 13354 (2008). The results of the 5th lower percentile were compared with the requirements of EN 13353 (2008). Among the studied species, Eucalyptus camaldulensis showed better glue line shear strength when compared to Eucalyptus urophylla. However, both species are potentially viable for the edge glued panel (EGP) production, since they meet the minimum requirement of 2.5 MPa, referring to the 5th lower percentile, as established by EN 13353-2008 standard. Based on the results, it is recommended the use of EPI adhesive with the amount of glue of 150 g/m² for the bonding of the wood of these species, aiming at the production of EGP.

Surface roughness of edge glued panels (EGP) of amazon maneged species

ABSTRACT In the Amazon, the sustainable use of wood is associated with technological research that indicates industrial use. Surface roughness of wood is an important criterion for assessing tool condition, machining performance and product quality. The objective of this study was to evaluate the surface roughness of five Amazonian woods used in the manufacture of EGP (Edge Glued Panels).The woods Angelim pedra, Angelim vermelho, Breu vermelho, Murici and Piãozinho, obtained from managed areas of the Amazon, were used in the manufacture of EGP panels. Surface treatments were performed with 120 and 180 grit sandpaper. Surface ripples (roughness) were measured using a digital roughness meter with needle (n = 180 readings). Physical and mechanical tests were performed on both wood and EGP samples, to verify the possible relationship between these properties and roughness. EGP Piãozinho presented better surface quality, which consists of lower roughness (lower surface wave height), while EGP Angelim pedra presented uneven surfaces. Surface quality was satisfactory when 120 grain sandpaper was applied to most products. The results showed a highly significant effect of roughness such as the physical-mechanical properties. The highlight of the study is the wood and EGP Piãozinho, because in all the tests, it always presented the best performances.

Medium-density Fiberboard (MDF) and Edge-glued Panels (EGP) after Edge Milling - Surface Roughness after Machining with Different Parameters

The mean arithmetic deviation of the roughness profile was investigated during cylindrical milling of the board edges. The machined materials were a medium-density fiberboard, medium-density fiberboard with single-sided lamination, and edge-glued spruce panel. Contactless and contact profilometers were used to measure the roughness. Both methods were evaluated and compared. Tungsten carbide blades with three different compositions and treatments were used. The effect of the cutting speed (20 m/s, 30 m/s, 40 m/s, and 60 m/s) and feed rate (4 m/min, 8 m/min, and 11 m/min) on the surface roughness was also monitored. The results of this study compared two different methods for determining the surface roughness. The measurements were more accurate with a contactless profilometer, but the price is higher than that of the contact method. The operation was also more complicated, and the measurement itself took longer with a contactless profilometer. The evaluation of individual surface quality variables was faster with a contact device. The best results in terms of the surface quality were achieved by lowering the feed rate and increasing the cutting speed.

Surface roughness of medium-density fiberboard (MDF) and edge-glued panel (EGP) after edge milling

The mean arithmetic deviation of the roughness profile (Ra) was investigated for the edge surface after edge milling of medium-density fiberboard, medium-density fiberboard with single-sided lamination, and spruce edge-glued panel. Tungsten carbide blades with three different compositions and treatment (HW1, HW2, and HW1 + CrTiN coating) were used. During edge milling, the feed rate (4, 8, and 11 m/min) and cutting speed (20, 30, 40, and 60 m/s) were changed. The lowest roughness values were found in spruce timber, and the highest values were found in untreated MDF. The highest edge surface roughness was measured after using the HW2 tool. Slightly lower values were found using HW1 CrTiN, and the lowest values were found using HW1. Increasing the cutting speed led to a very slight increase in roughness. Increasing the feed rate had the same effect, but its effect was more significant. The article provides an understanding of the interaction of the most frequently occurring factors relative to the quality of the work surface of the large-area materials.

Power consumption during edge milling of medium-density fiberboard and edge-glued panel

This paper presents the energy consumption differences during the edge milling of various board materials (medium-density fiberboard (MDF), medium-density fiberboard with single-sided lamination (MDF-L), and spruce edge-glued panel (SEGP)). The edge milling was carried out with various parameters: feed rate (4, 8, and 11 m/min); cutting speed (20, 30, 40, and 60 m/s); and blade type (tungsten carbide HW1, HW2, and HW1 coated with CrTiN (HW1 + CrTiN)). The results indicated that the increase in the cutting speed and feed rate cause the increase in cutting power. The highest cutting power values were observed with the milling of MDF; slightly lower values were observed with MDF-L, and the lowest values were observed with SEGP. Very similar cutting power values during milling were noted with HW1 and HW2 blades, whereas milling with the HW1 + CrTiN resulted in slightly higher values (e.g., 1% higher).

Evaluation of pressing time in the production of edge glued panel with adhesive polyurethane derived from castor oil

Edge-glued panels are composed by the lateral and top gluing with adhesives of solid battens. These panels use small pieces of wood, offering an optimal usage of forest resources and the development of higher value-added products. The adhesive generally used to produce the panels are the synthetic ones (PVA or EPI). The polyurethane derived from castor oil may arise an alternative to replace the adhesives derived from non-natural origin, because it has no solvent in its composition, is a biodegradable material and it comes from a renewable resource. The bonding quality of this panel was performed according to BS EN 13353, which specify the minimum resistance values for panels under different humidity and temperature conditions applied to the international market. In this context, the aim of this paper was to evaluate the lateral gluing quality of Pinus taeda panels using the polyurethane derived from castor oil, as well as assess the pressing time effect on the bonding quality. The adhesive was applied into the battens surface in weight of 180 g/m2. The panels were put into a cold press machine for 1, 2, 4, 8 and 24 h, totalizing five conditions and eight together/replications. The bonding quality of this panel was performed according to BS EN 13353 and BS EN 13354, under different humidity and temperature conditions. The results were submitted to statistical analysis by outlier tests, normality test, homogeneity variance, analysis of variance and mean comparison, all with 95 % reliability. The polyurethane showed acceptable values to EN-13353 for 4 h in the press machine. The test for critical humidity and temperature conditions showed a reduction in the adhesive bond strength, but still acceptable to EN-13353. Under these circumstances, it is concluded that the polyurethane derived from castor oil may be an alternative to produce lateral glued panels for dry conditions and internal and external applications for humid conditions.

EDGE Glued Panels Grading through Transversal Vibration Testing

The Edge-Glued Panel is produced using sawn wood, i.e., lumber, with or without butt joints and edge-glued lumber. It can be composed with one layer, but the most common is with three layers (two external longitudinal and one transversal). This panel is used in Europe for furniture and forms of concrete structures. The resin applied in the gluing is based on urea-formaldehyde and phenol-formaldehyde. Due to the importance of this panel, this research aims to analyze the use of Transversal Vibration techniques for EGP grading. For this purpose, twelve EGP panels of three layers were produced and tested in order to determine the modulus of elasticity and modulus of rupture in static bending and dynamic modulus. The results showed nonexistent correlations among the dynamic modulus of elasticity with EGP density and between the modulus of rupture in static bending with the dynamic modulus, providing just a good correlation between statistic and dynamic modulus of elasticity.

Efeito da gramatura sobre a qualidade de colagem lateral da madeira de Tectona grandis

Tectona grandis Linn f. wood (teak) is suitable for making Edge Glued Panels (EGP) due to its dimensional stability, physical, mechanical and chemical properties and its resemblance to hardwoods such as mahogany. In generating those products, a highly important variable is the grammage of the adhesive. In this context, this study aimed to evaluate the effect of grammage on the quality of bonded joints of Tectona grandis. To achieve this work teak wood and adhesive polyvinyl acetate were used. The density and the moisture content of the wood were evaluated according to the standard COPANT 461/1972 and 460/1972, respectively, and the chemical properties in accordance with TAPPI standards. The joints were glued using four grammages: 100 g m-2, 140 g m-2, 180 g m-2, and 220 g m-2. The quality of bonding was evaluated by means of shear strength and tested according to EN 13354/2003. The results showed that the mean apparent specific mass was 559 kg m-3, the average moisture content was 7.74% and the total content was 8.27% extractives. The bonded joints showed variation in shear strength of 0.924 MPa to 1.35 MPa for the wet state and 3.01 MPa to 5.43 MPa for dry conditions. There was no statistically significant difference between the averages of the different weights used on the quality of the EGP panels collage. It was concluded that the teak wood had adequate values of properties of wood, glued together had qualified values for the Brazilian standard for shear testing and the best condition was found with a weight of 140 g m-2.

Determination of Optimal Machining Parameters of Massive Wooden Edge-Glued Panels Made of European larch (Larix decidua Mill.) using Taguchi Design Method

In this paper, the optimization of computer numerical control (CNC) machining parameters were conducted using the Taguchi design method on the surface quality of massive wooden edge glued panels (EGP) made of European larch (Larix decidua Mill). Three machining parameters and their effects on surface roughness were evaluated. These parameters included tool clearance strategy, spindle speed, and feed rate. An analysis of variance (ANOVA) was performed to identify the significant factors affecting the surface roughness (Ra and Rz). Optimum machining parameter combinations were acquired by conducting an analysis of the signal-to-noise (S/N) ratio. Optimal cutting performance for the Ra and Rz was obtained for the cutter at a tool clearance strategy of an offset 16000 rpm spindle speed and 1000 mm/min feed rate. The surface roughness, both the Ra and Rz, increased with increasing feed rate. Optimal cutting performance for Ra and Rz was obtained for a tool clearance strategy of an offset 16000 rpm spindle speed, and 1000 mm/min feed rate cutting settings. Based on the confirmation tests, Ra decreased 2.2 times and Rz 1.8 times compared to the starting cutting parameters.