Wayan Darmawan

Characteristics of laser melted AISI-T1 high speed steel and its wear resistance

Abstract For many wood machining processes, the interest of tool steels remains very important because of their good tool edge accuracy and easy grinding. The main problem is their low resistance to wearing and moderately toughness. To increase their performance, a laser treatment applied on the tool edges was presented in this paper. First, the surface of AISI-T1 samples was scanned by a laser beam with varying laser treatment conditions (laser power and scanning speed). Second, an investigated laser treatment condition promising good characteristics (high hardness, high melt volume, no cracks) was chosen and applied on T1 peeling tool edges, then its wear resistance was tested for peeling beech wood. The experimental results show that the microhardness of the melted T1 samples was affected by the laser power and the scanning speed. The microhardness was slightly increased with increasing laser power and with decreasing scanning speed. The microhardness of the melted T1 samples under each treatment conditions after three times one hour each tempering at 550°C was higher than that of the conventionally hardened T1. The melt volume of the laser treated T1 samples was also increased with increasing laser power and with decreasing scanning speed. The laser treatment condition with a laser power of 3000 W and a scanning speed of 200 mm min−1 was considered to provide good characteristics and was applied for melting the edge of T1 peeling tool. The wear resistance and wear pattern of the melted T1 peeling tool in peeling beech was better than those of the conventionally hardened T1 peeling tool.

Improvement in wear characteristics of the AISI M2 by laser cladding and melting

The interest of high speed steel (HSS) for wood cutting tools remains very important because of their good tool edge accuracy and easy grinding. The main problem is their low resistance to both mechanical and chemical wearing. Resistance of HSS cutting tools to wearing is a primary concern in the applicability of the HSS cutting tools to a wood cutting operation. In order to increase their performance, a laser melting and cladding applied on the tool edges is presented in this paper. First, the annealed AISI M2 bar was melted, and the M2 powder was cladded onto the AISI L2 substrate by a laser beam. The microstructure and microhardness of the M2-clad and M2-melted were characterized. Second, their wear resistance was tested for cutting wood. The experimental results showed that the microstructures on the clad zone (CZ) of M2-clad and melted zone (MZ) of the M2-melted reveal fine and homogeneous iron dendritic structure, in which whole primary carbides were completely dissolved during laser cladding and me...

Juvenile and mature wood characteristics of short and long rotation teak in Java

Teak wood ( Tectona grandis ) as an important forest resource in Indonesia has been processed to wood furniture in large quantities to fulfill an increasing need of both local and international consumers. To satisfy the increasing demand for wood products, teak wood has been supplied from the State forests (Perhutani) and Community teak plantations. Community teak has been harvested at shorter age rotations (7–10 years) than Perhutani teak (40–60 years). This paper discusses the occurrence and characteristics of juvenile wood in Perhutani and Community teak based on density, shrinkage, bending strength (modulus of rupture - MOR, modulus of elasticity - MOE), fiber length, and microfibril angle (MFA). A segmented modeling approach was used to find the juvenile mature transition. Fiber length and MFA appear to be good anatomical indicators of radial increment demarcation between juvenile and mature wood, although maturation radial increment varies slightly between the fiber length and MFA. The use of radial increment density, shrinkage, MOR, and MOE were not appropriate, because of low coefficients of determination and a large range of radial increment for transition from juvenile to mature wood. The maturations were estimated to start at radial increments 10 and 14 cm from the pith by fiber length, and 11 and 15 cm from the pith by MFA for Perhutani and Community teak, respectively. The projected figures for the proportion of juvenile wood at breast height for Perhutani and Community teak were 65% and 100%, respectively. The results also indicate that short-rotation Community teak was not remarkably inferior in shrinkage, MOE and MOR compared to Perhutani teak, although it was less dense, less attractive and less durable due to lower heartwood content. Therefore, careful attention should be given to the use of the Community teak in some wood-processing technologies.

Wettability and bonding quality of exterior coatings on jabon and sengon wood surfaces

Wettability and bonding quality of exterior coatings on fast-growing wood surfaces were studied. Samples of air-dried flat-grained (tangential surface) and edge-grained (radial surface) pattern of jabon (Anthocephalus cadamba) and sengon (Paraserianthes falcataria) woods were used. Before application of exterior coatings, the surfaces of the lumber samples were sanded. To provide wood surfaces with various degrees of roughness, abrasive papers of 120, 240, and 360 grits were used for the surface preparation. The wettability of two exterior coatings (water-based acrylic and oil-based alkyd varnishes) on the sanded wood surfaces was measured using a sessile drop contact angle method. The Shi and Gardner (S/G) model was used to evaluate and compare the wettability of the surface coatings on the wood. The sanded wood samples were coated with the two coatings (two layers each). Bonding quality of the coating layers was measured using a crosscut tape test method. Experimental results show that constant contact angle change rate (K value) of the S/G model decreased as the grit number of abrasive paper increased. This indicates that the wettability decreased as the roughness of the surface decreased (surface becomes smoother). There was no evidence of differences in wettability between tangential and radial wood surfaces. The oil-based alkyd coating generated better wettability compared to the water-based acrylic. The crosscut tests showed that the bonding quality of the coating films on both jabon and sengon wood decreased as the surface became smoother. The sengon wood compared to jabon wood provided better coating wettability and bonding quality. Wettability in terms of the K values was a good indication for determining the bonding quality of the two varnish layers.

Performance of helical edge milling cutters in planing wood

A new design of a milling cutter with solid helical edge has been developed for improving the performance of cutting wood. Development of the new helical edge milling cutter with its geometries for planing wood has been followed by some research progresses. In this work, a conventional edge milling cutter and helical edge milling cutters were tested in planing spruce wood (Picea abies). The purpose of the research work was to investigate chip flow, power consumption, noise emissions, edge wear, and surface roughness characteristics of the helical edge milling cutters in planing spruce wood. Experimental results showed that the helical edges compared to the conventional edge milling cutter provide better chip flows with nearly axial direction and low flight velocity. Though the extreme helical edges up to 75° inclination angle generate comparable or slightly larger cutting power than the conventional edge, they considerably generate lower sound pressure level of up to 5 dB(A). The helical edge milling cutters are better in wear resistance, suffer less edge fractures, and produce better surface quality of planed wood than the conventional edge milling cutter.ZusammenfassungNeuartige Umfangsplanfräswerkzeuge mit schraubenlinienförmigen Schneiden (extremen Werkzeug-Neigungswinkeln λS) sind zur Verbesserung des Zerspanungsverhaltens an Massivholz entwickelt worden. Im Beitrag werden Untersuchungen der neuartigen Fräswerkzeuge im Vergleich zu einem herkömmlichen Werkzeug bei der Bearbeitung von Fichte (Picea abies) dargestellt. Dabei stehen der Spanflug, die Schnittleistung, die Lärmemissionen, der Schneidenverschleiß und die Oberflächenqualität im Mittelpunkt der Betrachtungen. Die Experimente haben eindeutig bewiesen, dass die Werkzeuge mit schraubenlinienförmigen Schneiden einen nahezu axialen Spanflug mit stark verringerten Fluggeschwindigkeiten aufweisen. Es wurde ein vergleichbarer Betrag bzw. ganz leichter Anstieg der Schnittleistung an den Werkzeugen mit extremer Schneidenneigung bis 75° im Gegensatz zum herkömmlichen Fräswerkzeug ohne Schneidenneigung registriert. Bemerkenswert ist jedoch die festgestellte starke Senkung des Schalldruckpegels von bis zu 5 dB(A). Auch bezüglich des Verschleißes sind die neuartigen Werkzeuge bedeutend resistenter und es wurden weniger Schneidenausbrüche gefunden. Die gemessene Werkstückqualität, beschrieben über die Oberflächenrauheit, ist besser als bei Bearbeitung mit dem herkömmlichen, konventionellen Werkzeug ohne Schneidenneigung.

Wear characteristics of multilayer-coated cutting tools when milling particleboard.

This article presents the characteristics of delamination wear on the clearance face of newly coated K10 cutting tools when milling particleboard. The K10 cutting tools were multilayer coated with ...

Performance of samama (Anthocephalus macrophyllus) LVL based on veneer thickness, juvenile proportion and lay-up

ABSTRACT A study to determine the quality of laminated veneer lumber (LVL) from samama wood (Anthocephalus macrophyllus) was carried out. Samama is a fast-growing endemic wood in eastern Indonesia. Factorial of three factors in RAL design was used to investigate the influence of veneer thickness, juvenile proportion and veneer lay-up to the quality of the resulted samama LVL. The veneer thicknesses were 1.5 and 3.0 mm. Juvenile proportions were arranged in five levels, which were 100% of juvenile veneer, 100% of mature veneer and combination of both juvenile and mature with juvenile proportion of 14%, 43% and 71%. Two veneer lay-up used in this study were loose side met loose side and tight side met loose side. The result of the study showed various specific gravity of LVL by different proportions of juvenile. This factor also affected the other physical traits. Shear strength of the LVL was equal to the solid wood, yet MOE and MOR were affected by juvenile proportion and veneer lay-up. LVL developed from 100% of mature veneer exhibited the highest MOE and MOR, yet no significant difference was noted in MOE and MOR between LVL 100% of juvenile and other tested juvenile proportions.

Erratum to: The effect of juvenility and veneer thickness on bending strength of Douglas-fir laminated veneer lumber

Most of wood industry requires well conformed logs and middle diameter trees to optimize primary processing yields. The raw material, mostly coming from monoculture plantations, contains a considerable proportion of juvenile wood. The objectives of present study were to identify the transition ring between juvenile and mature wood in Douglas-fir and to analyze the effect of juvenility and veneer thickness on bending strength of Douglas-fir laminated veneer lumber (LVL). Microfibril angle (MFA) and tracheid length from five Douglas-fir logs were measured from pith to bark. Veneers peeled with an instrumented lathe to produce LVL. Total of 140 LVL samples were mechanically characterized by measuring modulus of elasticity (MOE) and modulus of rupture (MOR). The results showed that transition rings from juvenile to mature wood at breast height, according to MFA and tracheid length, were at twentieth and twenty-first, respectively. According to analysis of variance, there was a significant effect of juvenility on LVL bending strength. The advantage of using veneers of mature compare to juvenile wood for LVL was due to an improvement of bending strength in the range of 7–22 %. LVL made of 3 mm veneers has lower stiffness (2.2 %) compare to LVL made of 5.25 mm veneers. High correlation between static and dynamic MOE was noted.

Karakteristik Aus Mata Pisau Terlapisi Bahan Pengeras pada Pemotongan Kayu Mersawa dan Papan Partikel

The use of mersawa wood and particleboard as a materials has been increasing for building constructions and decorative purpose. In previous study reported that, these materials provide a high rate of wear caused by abrasion (high silica) and resin content. This article presents the characteristics of wear on the clearance face of newly multilayer-coated K10 cutting tools when milling mersawa wood and particleboard. The K10 cutting tools were coated with monolayer titanium aluminum nitride (TiAlN), multilayer TiAlN/titanium silicon nitride (TiSiN), and TiAlN/titanium boron nitride (TiBN). Mersawa wood with density of 0.80 g/cm 3 and particleboard with a density of 0.61 g/cm 3 were cut using the coated tools and uncoated K10. Cutting tests were performed on computer numeric control router at a high cutting speed of 17 m/s and a feed rate of 0.1 mm/rev to investigate the wear characteristics on the clearance face of these coated tools. Result of research shown that the coated tools experienced a smaller amount of wear than the uncoated tool when cutting the mersawa and particleboard. The best coating among other coated in this study was multilayer TiAlN/TiBN. The high hardness, low coefficient of friction, high resistance to oxidation, and high resistance to delamination wear of the multilayer-coated TiAlN/TiBN tool indicate a very promising applicability of this coating for high-speed cutting of abrasive woods and wood based materials.