• Journal of the Korean Wood Science and Technology
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• v.18 no.2
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• pp.79-85
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• 1990

Traditional complex joints have used to a wide variety of wooden furniture construction. Dowel joint is the most popular joint s. However design of this joint to meet specified service condition has been hampered by a lack of proven design formulas which can be use to predict their strength. The object of this study is to investigate the withdrawal strength and effect of dowel diameters in wood and wood based materials. The obtained results were as follows; 1. The relationship between withdrawal strength and dowel diameter is found to be linear. 2. Withdrawal strength of medium density fiberboard and Sepetir in end-to-side joints is superior to Antiaris, particleboard and plywood. 3. In end-to-end joints, withdrawal strength of medium density fiberboard is the most superior joint. but Sepetir. Antiaris and plywood have similarly strength and particleboard is inferiority. 4. Withdrawal strength in end-to-end joints of Antiaris and plywood is higher than in end-ta-side joints. But in end-to-end joints of Sepetir. medium density fiberboard and particleboard is similarity in end-to-side joints.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.1
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• pp.1-9
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• 2015

Wood fibers for medium density fiberboard (MDF) was used in the filler layer of the white duplex board for increasing thickness and bulk of the board. The MDF fibers were treated with ozone (3% based on dry weight of the fibers), and mixed together with OCC (old corrugated container) to form paper. Ozone-treated MDF fibers gave high bulk, high tensile strength, high internal bond and fast drainage to the furnish mixed with OCC. It was shown that there were possibilities to reduced basis weight of the filler layer without loss of thickness, stiffness, and tensile strength. Furthermore, it showed the possibility to develop a new kind of board product that has high stiffness as well as high strength properties with light basis weight by application of the ozone-treated MDF fibers.

• Journal of the Korea Furniture Society
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• v.18 no.1
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• pp.13-19
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• 2007

The influences of coating on oak veneer overlaid Medium Density Fiberboard (MDF) were evaluated. The hardness of 9mm-MDF by hardness test were increased about 28% with coating on MDF and the more increased hardness of 31% with oak veneer overlaid MDF. The hardness of veneer overlaid MDF increased with increment of the veneer thickness and that of overlaid MDF showed the higher hardness compared to non-overlaid MDF. The optimum moisture content in terms of the hardness of panels MDF was in the range of 7% to 10% and the hardness was decreased with increasing of the moisture content. Any cracks were not overlaid coated on the MDF but the cracks were observed on the overlaid MDF after Soak under Vacuum Dry 10-cycle. The thicker veneer-overlaid MDF showed more cracks.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.231-240
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• 2016

The change in chemical compositions of leachate and medium density fiberboard (MDF) from a laboratory-scale simulated landfill which constructed in a plastic container containing alternating layers of soil and MDF was investigated to evaluate decomposing of MDF in soil. Four treatments were conducted: 1) MDF in soil, 2) MDF only, 3) cured UF resin in soil, and 4) soil only. Molecular weight (MW) distribution of compounds in leachate from soil only treatment did not change over time. In UF resin in soil treatment, the MW distribution shifted to a lower MW distribution over time, while the peak shifted to the left indicated changing to higher MW distribution in leachate from treatment 1 and 2 contained MDF. Higher percent nitrogen in leachate was observed in MDF containing treatments due to the UF resin in the MDF. The percent carbon slightly increased in MDF only while that greatly decreased in MDF in soil treatment maybe due to bacterial activity. The percent of extractable materials from the MDF decreased greatly on day 35 compare to day 0, and subsequently did not change much on day 77. In contrast, percent holocellulose and lignin did not change much over time. No structural change of the wood fiber in MDF occurs during the study. Water-soluble materials from MDF in soil contributed the change in chemical composition of leachate.

• Journal of the Korean Wood Science and Technology
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• v.43 no.5
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• pp.548-557
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• 2015

This study investigated environmental assessments of leachate containing formaldehyde from medium density fiberboard (MDF) disposed in laboratory-scale simulated landfills. Environmental impact assessment of leachate was conducted by measuring formaldehyde, toxicity, biochemical oxygen demand (BOD), chemical oxygen demand (COD), bacterial enumeration, and pH. Amount of formaldehyde in leachate from MDF in soil decreased to the level of soil only treatment by 28 days, and toxicity decreased as the amount of formaldehyde decreased. BOD and COD levels in leachate from the treatments containing MDF exceeded permissible discharge levels of BOD or COD throughout the experimental period. The pH levels of all treatment were within permissible discharge range except on day 0. Fewer bacteria were observed in leachate from MDF in soil treatment than other treatments (MDF only, cured UF resin in soil, and soil only). Consequently, the leachate from disposal of MDF in soil detrimentally affect on environment. However, soil buffered formaldehyde leaching and pH on leachate in this study. Waste MDF may be required the pre-water soaking treatment for leaching formaldehyde to reclaim on land.

• Food Engineering Progress
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• v.14 no.2
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• pp.106-111
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• 2010

In this study, we performed corrugation fluting experiments to examine the relationship between high-low corrugation of a corrugated medium and compressive strength of corrugated containers for food packaging. A low-grade corrugated medium was found to suffer from weak tensile resistance and to be prone to stealing, which tends to produce low corrugation. In contrast, a medium with a large corrugation deviation often caused slimming during fluting and produced irregular corrugations. Experiments of high-low corrugation distribution according to corrugated medium grades indicate that a high grade medium shows a smaller ratio of low corrugation. The thickness of corrugated fiberboard is weakly correlated to the basis weight of medium, yet positively correlated to the medium thickness (y=3.9732x+4.2712, $R^{2}=0.8142$) and inversely proportional to the medium density (y=-3.1213x+6.8736, $R^{2}=0.9919$). Compressive strength of a corrugated fiberboard box is low, if made of corrugated medium with large low corrugation distribution. Compressive strength showed 13% variation with respect to medium grades and 21% variation for various test samples. The corrugation fluting of a corrugated medium is related to physical properties such as basis thickness and density.

• Journal of the Korean Wood Science and Technology
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• v.25 no.1
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• pp.50-55
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• 1997

This study was carried out to utilize old newspaper(ONP) and paper sludge more effectively, and also to elucidate the influences of pressing conditions on the medium density fiberboard(MDF) properties. MDFs were made from ONP and low grade of paper sludge by wet process with change of pressing time, temperature and pressure. MDFs of ONP were more affected by pressing conditions, especially pressing pressure, but temperature and pressing time were also important. According to mixing paper sludge to ONP tensile and bending strength of MDF were decreased, but density and dimensional stability were improved. These results indicated that some physical properties of MDF can be improved by paper sludge and it is possible to use it in MDF.

• Journal of the Korean Wood Science and Technology
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• v.29 no.3
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• pp.27-35
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• 2001

Four different sources of wood-fibers from Eucalyptus, Italian poplar, hemlock, and mixed species fibers were used to study the influence of their fiber characteristics on the performance of medium density fiberboard (MDF) panels bonded with both urea-formaldehyde (UF) and phenol-formaldehyde (PF) adhesives. Included fiber characteristics were fiber length, size distribution, bulk density, and acidity. Physical and mechanical properties of MDF panels manufactured by dry process using these different fibers were determined for the comparison of board performance. Two hardwood species had a large fraction of short fibers resulting in a higher bulk density while very long hemlock fibers had lower bulk density. Fiber acidity was revealed to strongly affect the internal bond (IB) strength of MDF panels bonded with UF resins. MDF panels made from mixed species fibers showed highest IB strength of all panels prepared. UF-bonded MDF panels showed poor dimensional stability. In conclusion, the present study showed that wood-fiber characteristics such as fiber length, bulk density, and acidity affect the performance of MDF boards, and also suggested that fiber characteristics be considered for MDF panel manufacture.

• Journal of the Korea Furniture Society
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• v.16 no.1
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• pp.9-16
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• 2005

This study was carried out to displace traditional virgin wood fiber by exploded MDF-waste fiber for the manufacture of medium density fiberboard. MDF waste was exploded in condition of $215^{\circ}C,20$ minutes. The higher the mixing ratio of exploded MDF-waste fiber, the lower the MOR and IB of MDF. There was no difference of formaldehyde emission by desiccator method between virgin wood fiber and exploded MDF-waste fiber. Adding $25^{\circ}C$ of exploded MDF-waste fiber met the KS of MDF 15 type.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.137-145
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• 2005

The present research deals with structural analysis and optimal design of the heating drum of a hot-rolling press for medium density fiberboard. Stress concentration in the journal of the heating drum is analyzed by the submodel technique of the finite element method. The fatigue life under operating conditions is analyzed and evaluated by the stress-life theory. Shape optimal design problems, to minimize the maximum stress occurring in the journal, are formulated and shape parameters of the corner fillets of the journal are defined as the design variables. The problems are solved by the numerical optimization method and optimal shapes are found. The optimal designs are shown to be reliable in terms of the maximum stress and the fatigue life.