Edge-glued Panels Research Articles

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

An artificial neural network (ANN) approach was employed for the prediction and control of surface roughness (Ra and Rz) in a computer numerical control (CNC) machine. Experiments were performed on a CNC machine to obtain data used for the training and testing of an ANN. Experimental studies were conducted, and a model based on the experimental results was set up. Five machining parameters (cutter type, tool clearance strategy, spindle speed, feed rate, and depth of cut) were used. One hidden layer was used for all models, while there were five neurons in the hidden layer of the Ra and Rz models. The RMSE values were calculated as 1.05 and 3.70. The mean absolute percentage error (MAPE) values were calculated as 20.18 and 15.14, which can be considered as a good prediction. The results of the ANN approach were compared with the measured values. It was shown that the ANN prediction model obtained is a useful and effective tool for modeling the Ra and Rz of wood. The results of the present research can be applied in the wood machining industry to reduce energy, time, and cost.

Simulation Analysis of In-Service Bamboo and Pine EGP Composite Flooring

Bamboo is a renewable material that has been gaining attention in several sectors of production and research because of its potential. Its special characteristics of rapid growth, short harvest cycle, diversity and excellent mechanical properties. The objective of this work was a physical-mechanical analysis of flooring manufactured by a combination of bamboo (Dendrocalamus giganteus) laminate slats and wood (Pinus taeda) edge-glued panels (EGP). It was based on the ASTM D2394-83/1994 standard, which describes the procedures for mechanical simulation of in-service floors, such as indentation loads applied on small areas, falling ball impact, rolling load, abrasion and friction tests. The results were satisfactory when compared with those of other types of wood. The research showed lignocellulosic composite of Pine EGP with a bamboo surface, in terms of mechanical strength according the ASTM’s standard, is viable and feasible. Therefore, it results that “EGP/Bamboo” composite can be successfully applied for internal floors.

Effect of Wood Moisture Content in Edge Glued Panel Bonding for Furniture Industry: Analysis of Shear-Stress and Rupture in Bondline

The objective of this article was to study the influence of the Pinus taeda wood moisture content to the production of EGP (Edge Glued Panel) in the bonding stage, using PVA adhesive. It was analyzed the joint resistances through shear-stress tests and rupture in the bondline. The wood moisture classes adopted to the panels were: “A” ( [8%, 9%[ ), “B” ( [9%, 10%[ ), “C” ( [10%, 11%[ ), “D” ( [11%, 12%[ ) e “E” ( [12%, 13%[ ). After the panel production, it was sawn the specimens for the resistance shear in the bondline tests by traction. The tests results show that it was statistically significant differences to the values of rupture tensions between A class and B, C, D and E classes. The wood medium rupture presented a tendency to reduce with the moisture increase, and the total rupture in the bondline presented a small tendency of a less number of occurrences with the rupture tension increases.

The Influence of Process Parameters on the Surface Roughness in Aesthetic Machining of Wooden Edge-Glued Panels (EGPs)

This study explored the effect of processing parameters on surface roughness as a result of aesthetic designs processed on walnut, chestnut, and beech wood edge-glued panels (EGPs) by CNC (computer numerical control) router. To accomplish this, the average roughness value (Ra) on an engraved surface in a Ying-Yang design treated on the material was measured. Using analysis of variance (ANOVA), the feed rate, spindle speed, step-over, and axial depth of cut factors; surface roughness factors; and the interactions between these factors were found to form significant differences at the level of 95%. At the end of the study, the Ra value was lower in walnut and beech EGPs (3.423 μm and 4.316 μm, respectively) and higher in chestnut EGPs (5.005 μm).

Production and properties of wood-welded panels made from two Canadian hardwoods

This study examines the suitability of wood welding technology for producing composite panels for furniture applications with two Canadian hardwood species, sugar maple (Acer saccharum) and yellow birch (Betula alleghaniensis). For each species, twelve 30 × 225 × 300 mm3 panels were manufactured using a panelling machine specifically designed for rotational wood-dowel welding with optimized parameters obtained from a previous study. Six edge-glued panels of the same size were manufactured from each species using a non-structural polyvinyl acetate adhesive and tested for comparative purposes. The experimental programme included three-point bending at 255-mm span and visual inspection of the panels to assess performance at standard moisture conditions and after an ageing cycle with variable relative humidity. Average breaking load of 1.79 and 1.70 kN was obtained at standard moisture conditions for welded panels of yellow birch and sugar maple, respectively. Fractures consistently occurred in the dowel’s cross section, whereas no slippage was observed along the welded interface. Delamination between wood slats occurred after the ageing cycle, but did not affect the bending properties. Results confirm the suitability of wood-dowel welding for producing furniture panelling with Canadian hardwood species. Further research is needed to design panels with a more efficient position and use of welded dowels and with panel product properties that are comparable or superior to those of glued counterparts.

BONDING BEHAVIOR OF Eucalyptus benthamii WOOD TO MANUFACTURE EDGE GLUED PANELS

The main objective of this study was to evaluate the performance of Eucalyptus benthamii Maiden et Cambage wood for the production of edge glued panels. Wood pieces with planed and sanded surfaces were bonded using cross-linking polyvinyl acetate (PVAc) and polyurethane (PUR) based adhesives, at pressures of 0.7 MPa and 1.0 MPa. The same adhesives were used for finger jointing at a pressure of 1.5 MPa. The bonding strength was determined through glue-line shear strength and bending test for finger jointing. According to the results, the pressure and surface preparation variables did not influence the glue-line shear strength of the adhesive PVAc, whereas for the PUR adhesive strength was influenced by the pressures and machining used. All treatments met the minimum values required by the standard; however, the highest bonding strength was found in the sample glued with PUR adhesive at a pressure of 1.0 MPa and sanded surface. The highest modulus of rupture was obtained in the samples glued using PVAc, while the modulus of elasticity was not affected by the type of adhesive used. These results enabled concluding that with regard to its technological properties assessed in the present study, E. benthamii wood is suitable for the production of edge glued panel.

Investigation of Parameters Affecting Surface Roughness in CNC Routing Operation on Wooden EGP

The aim of this study was to evaluate the effect of CNC routing, using different parameters with the Taguchi experimental design, on the surface quality of various wooden (pine, spruce, and beech) edge-glued panels (EGP). The study evaluated five processing parameters: cutting direction, cutting depth, cutting width, feed rate, and spindle rotation speed, and their effects on surface roughness on pine, spruce, and beech EGP. Based on the results of statistical analysis of the burr surface roughness values, the mentioned parameters affected panels at varying levels. It was seen that the parameters were only responsible for ~34% (Rz) of the roughness on the surface of pine EGP, ~49% (Rz) of spruce EGP, and ~27% (Rq) of beech EGP. Statistically important parameters were as follows: cutting direction for pine, cutting depth (tip diameter) and feed rate for spruce, and cutting direction and feed rate for beech.

Surface Preparation of Wood for Application of Waterborne Coatings

Abstract Year after year, water-based coatings gain market share due to new regulations on volatile organic compound emissions and voluntary certification programs. Work still has to be done on wood surface preparation, however, for water-based finishes to become truly reliable. In this research, water-based and solvent-based coatings were applied to edge-glued panels of yellow birch (Betula alleghaniensis Brit.). Sandpaper grits from 150 to 280 were used to prepare wood surfaces prior to coating application. A first series of specimens was prepared with a wiping stain and a second series with a spray stain. Contact angle measurements showed that surface preparation—more precisely the sandpaper grit—strongly affects water wettability and hence coating adhesion. Adhesion was found to change with the contact angle of the water. It was found that using a 150-grit sandpaper leads to unfilled wood cavities, high contact angles, and poor coating adhesion. At the opposite end of the range, using a 180-grit sandpaper leads to good wetting and good adhesion. In our tests, surface preparation had no significant effect on the color of systems using a spray stain. With a wiping stain, however, the grit of the sandpaper was found to affect the color of the specimens.

Consumer and manufacturer perceptions of hardwood panels made from character-marked lumber

Hardwood panels made from edge-glued material are a versatile product that could be within the reach of many smaller wood products firms. However, products would need to be accepted throughout the supply chain for this opportunity to be achieved. This study evaluated preferences of consumers and manufacturers towards edge-glued panels from Alaskan red alder and paper birch. A total of 11 panels were constructed, including different levels of character-mark features such as knots and natural stain. We found strong preferences for the birch panel having high levels of natural stain. This panel was also the highest rated panel on three attributes (character marks, grain consistency and overall colour). Both residential consumers and wood products producers preferred birch panels featuring natural stain to birch panels featuring knots. Both groups also preferred red alder panels that were either clear or with high levels of character (but not intermediate levels of character). Residential consumers favoured birch panels (versus red alder panels) to a greater extent than did wood product producers and generally were less familiar with red alder than were producers.

Paneles unidos de canto y contrachapados fabricados con madera juvenil de Eucalyptus nitens

SUMMARY This work evaluates the bonding quality in solid wood of juvenile (11 years) E. nitens. Edge-glued panels were manufactured and bonded with PVA (Polyvinyl acetate). The mechanical properties of the panels were determined and compared with those of mature (25 years) P. radiata panels. Shear strength values in E. nitens panels were found to be 35% higher than P. radiata panels according to British Standard EN 204-205 on non-structural adhesives for wood joining. Juvenile E. nitens wood venners were used to manufacture exterior ‐grade plywood panels. Laboratory results demonstrated that E. nitens plywood satisfies all the British Standard Institution requirements for exterior use.

Adoption of value-adding processes in Swedish sawmills

Adding value to lumber by processing it after sawing and standard drying is one means for the sawmilling industry to increase market shares in competition with other materials, e.g. glass, steel, concrete, aluminium, and plastics. In this study the adoption patterns of value-adding processes used in Swedish softwood sawmills were analysed based on production data from 1995. About 90% of the sawmills applied a value-adding process after initial sawing and drying, and 72% of the sawmills applied two or more processes. The total share of processed sawnwood was about 40%. Important dimensions of value-adding processes are: extra drying and production of blanks for doors/windows and for furniture; surface-treatment, mainly planing, which is sometimes associated with preservation and painting; length trimming and pallet production; extra drying and production of edge-glued panels and laminated beams; and stress grading and production of building components. The association of different value-adding dimensions with location, ownership and production characteristics were investigated. The total share of value-added production were higher for private sawmills than for mills owned by forest companies or by forest owners’ associations, and it was higher for mills in southern Sweden than for sawmills in other parts of the country. Value-added share does not clearly correlate with mill size or with the dominating tree species being sawn.