The study on glue-applying methods and hot-pressing technology of parallel strand lumber

Parallel strand lumber (PSL) was manufactured from the veneer strand cut from the poplar broken veneers of the plywood enterprises, by analyzing the influence of the size of veneer strands, the glue concentration and glue-applying time on the glue-absorbing amount of veneer strands, the influence of three different glue-applying was, hot-pressing time and temperature on the physical and mechanical properties of PSL was reviewed and the hot-pressing technology was optimized. The experiment results showed that the size of the veneer strands have not notable influence on the gluing-absorbing amount, and mainly affect the homogeneity and appearance quality of the product. The glue concentration is one main factor to affect the glue-absorbing amount of veneer strands and PF resin of 30% concentration was chosen. The glue-applying way is the main factor to affect the mechanical property of PSL. The hot-pressing time and temperature have significant influence on physical and mechanical properties of PSL. Comprehensively considering, the physical and mechanical properties and homogeneity of products are better using the veneer strands with 100 mm length, the glue-spraying way and hot-pressing technology with the time 35 min and the temperature of 150°C.

Steam-pressing mechanism of low density magnesia-bonded wood-wool panel

In this paper, wood-wool panel was prepared by steam pressing as opposed to the traditional cold-pressing and hot-pressing methods in order to eliminate the shortcomings of both methods. Cold pressed wood panels have low strength. The overall performance of heat pressed wood panel was poor. The water absorption of these two panels was too large. The steam pressing mechanism was studied by the means of X-ray diffraction and scanning electron microscope. The surface structure, moisture absorption and mechanical properties of wood-wool panel were investigated by experimental testing and numerical analysis. The surface structure of the wood-wool panel became stable, the moisture absorption was reduced, and the mechanical properties of the wood-wool panel were enhanced. The static bending strength of autoclaved wood-wool panel was 4% higher than that of cold-pressed wood-wool panel, and 7.4% higher than that of hot-pressed wood-wool panel. And the sound absorption coefficient increased by 6.3% and 5% respectively. The thermal conductivity was 2.4% lower than that of cold-pressed wood-wool panel.

Study on flame retardant leach resistant of modified poplar wood

After flame retardant and enhancing treatment, fast-grown poplar face the problem of leaching of pharmacy, which affected the effective permanence of the retard and further use is limited. In this paper, we study the fixed effect of low molecule phenol-formaldehyde (PF) resin on nitrogen and phosphorus (N-P) inorganic flame retardant composite under the condition of high relative humidity. The change of lateral sizes and quality of the specimens were emphasized in the experiment. Results reveal that the greater the concentration of flame retardant was, the greater weight gain percentage of the samples was, and the more serious leach was in the test, after the specimen was modified with the flame retardant. When weight gain percentage of the specimens is same, the greater the concentration of PF resin test solution was, better effect of the leach resistant will be obtained with the concentration of PF test solution increased. The PF resin with 25% concentration had the best effect to reduce the leach of N-P inorganic composite retards. From the comparative analysis above, it was advisable to indicate the PF resin with 25% concentration had the best effect to reduce the leach of N-P inorganic composite retards.

The dimensional stability of engineered wood f looring in heating systems

In this work, the effect of decorative veneer type, wood structure and wood shape on the dimensional stability was studied in a laboratory with a simulated heating system. Poplar/seven layer plywood engineered hardwood (structure C) or a 9 mm thick poplar substrate layer wood which contained the two veneer surface layers, structure A and structure B were used. The results indicated that whatever the structure and decorative veneer of flooring were, the dimensional stability of engineered wood flooring had a better performance in length; In width, with the same structure and decorative veneer, the dimension stability of engineered wood flooring with the veneer shape of mono-block was better than the shape of three splice; With the same decorative veneer, the dimensional stability of structure C was best, the second was structure B, and structure A was the worst; With the same structure, the dimensional stability of engineered wood flooring decorated with birch was best, the second was eastern black walnut, the third was eucalyptus, and maple was the worst. Thus, the engineered wood flooring of structure C decorated with birch with mono-block veneer was judged to be better for the dimensional stability.

Research on cutting performance of ceramic cutting tools in milling high density fiberboard

The effect of cutting parameters and tool parameters on cutting forces and tool wear were investigated in high density fiberboard (HDF) peripheral up-milling using toughened ceramic cutting tools. The results showed that whether at low speed cutting or high speed cutting, the tangential forces Ft and normal forces Fr increased slowly with the increase of cutting length. The tangential forces Ft and normal forces Fr at low speed cutting were higher than that at high speed cutting. The tangential forces Ft and normal forces Fr decreased with the decrease of wedge angle in the same rake angle. Then, the effect of high cutting speed on the flank wear was greater than that at low cutting speed. The bigger wedge angle tools led to the serious flank wear. The main wear pattern in milling HDF consisted of pull-out of the grain, flaking, chipping and cracking, the main wear mechanism were adhesive and abrasive wear.

Study on factors affecting the sound absorption property of magnesia- bonded wood-wool panel

Magnesia-bonded Wood-Wool Panel is a kind of environmentally friendly inorganic material with wood-wool as matrix materials, and magnesium oxychloride cement (MOC) as binder which is also a kind of porous material with nice sound absorption property. In this study, through single factor experiments, it was found that The thickness of the panel, molar ratio of MgO/MgCl2/H2O, wood-wool length influenced material sound absorption performance of the panel significantly. The thickness of the panel was the most significant factor affecting the panell’s sound absoption property, while the effects of density of the panel and weight ratio of magnesia to wood were not significant. The optimal factors were obtained through orthogonal experiments: Thickness of the panel 25 mm, molar ratio of MgO to MgCl2 to H2O 5: 1: 10, density of the panel 0.65 g.cm-3, weight ratio of magnesia to wood 1.25, wood-wool length 200 mm.

Influence of wet and dry cycle on properties of magnesia-bonded wood-wool panel

In this paper, magnesia-bonded wood-wool panel was subjected to different times of wet and dry cycle to analyze their effects on the physical properties and the sound absorption property of the panel from macro and micro perspective. The results showed that with the increase of the wet and dry circle times, both MOE and thickness swelling decreased and the average absorption coefficient of the specimen increased.