This study presents the results of tool wear and surface roughness of wood processed by plain milling. The tests were done on wood samples of pine and black alder grown in Lithuania in order to clarify time-related tool blunting and the aspects of surface formation. The samples were milled along the fiber in the experimental wood cutting stand at two different cutting and feed speeds. The roughness parameter (Rz) of the processed samples was measured in five sectors along and across the fiber using a contact profilometer. Registered values were analyzed by a Gaussian digital filter and evaluated according to relevant statistics seeking to minimize influence of wood anatomy. The obtained results helped to determine distinctions and variations of surface roughness, which strongly depend on the cutting path, rounding radius of the tool’s cutting edge, cutting, and feed speeds while milling pine and black alder.

It is known that PVA dispersion exhibits very good adhesion with natural wood. However, still remains unclear what adhesion-related changes occur, when the outside factor, i. e. ammonia, affects bonding or what the stability of bonding strength is, when the moisture content of ammonia modified wood increases. The aim of this work was to assess adhesive properties of ammonia modified oak wood and the bonding strength of PVA adhesive and modified wood, and to evaluate suitability and boundaries of PVA adhesive for bonding ammonia modified wood.

DOI: http://dx.doi.org/10.5755/j01.ms.19.2.4433

Most pieces of case furniture (kitchen and bathroom furniture, cabinets, wardrobes, tables and etc.) are made of 18 mm thick wood particle boards finished with various coatings. This three-layered constructional material is obtained by bonding wood particles of different fractions with synthetic resins using heating. The exploitation duration and quality of case furniture is determined by the mechanical properties of wood particle boards and the construction of joints of wood-based panels. On a frequent basis, pieces of case furniture with non-dismantable and dismantable construction are joined by using multidowel glued joints and cam connecting fittings intended for furniture, respectively. Wood-based panels can be joined with mitre joints whose mechanical properties have not undergone testing and comparison with regular joints when applying insertable wooden dowels or furniture connecting fittings. During the testing of particle board properties it was established that joining wood-based panels in this way ensures most efficient use of mechanical characteristics of the particleboard. In addition to the properties of the mitre joint, the tests also allowed determining the bending strength, tensile strength and bonding strength of the constructional material, and providing an original method for testing board properties, which can be successfully applied to the prediction of properties of the mitre joint. Tests were performed by using a universal tensile testing machine P-0.5. Joints were bonded by applying PVA dispersion. The surface of boards was veneered by using mahogany veneer and urea formaldehyde resin. It was found that mitre joints of wood particle boards can withstand loads that are higher from 2 to 4 times, in comparison to glued doweled joints or joints constructed with cam connecting fittings.

DOI: http://dx.doi.org/10.5755/j01.ms.18.4.3095

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