Tool Wear Effect on Cutting Forces: In Routing process of Aleppo Pine Wood

This paper uses the cutting forces in a routing process of Aleppo pine wood to estimate the tool wear effect. The aim is to obtain further information about the tool wear effect by monitoring the variation in the cutting forces. A Kistler 9257A 3 axes Dynamometer was positioned under the workpiece to measure the cutting forces at frequencies up to 10,000 Hz. The experiments were carried out on a CNC routing machine RECORD1 of SCM. A carbide tool was used and the cutting parameters were fixed. The cutting speed was approximately 25 m/s. Dasylab software was used to capture the data. The results show a correlation between the tool wear and the computed angle ( ), between the tangential and cutting forces. In fact, the variation of ( ) is unstable in the running period and stable in the linear wear zone, included in the interval [−1.11°; −1.10°]. This study was performed as part of a development program for the Algerian wood industry, hence the selection Aleppo pine wood as the working material.FCBA Institut Technologique, FSE (Fond Social Européen), CRB (Conseil Régional de Bourgogne) and University of Boumerdes (Algeria

Influence of veneer quality on beech LVL mechanical properties

The quality of peeled veneers is generally quoted considering 3 main criteria: surface roughness, thickness variations and lathe checking. This last criterion impacts on mechanical properties of by-products. It is well known that lathe checking occurrence can be reduced applying a good hygrothermal treatment of the round-wood before peeling coupled with optimised setting of pressure bar on the peeling lathe. It is also well known that thicker the veneer is and more difficult it is to reduce lathe checking and the other veneer defects. The tendency being to manufacture more eco-friendly engineering wood products using less glue, it is of interest to design such products with thicker layers and so less glue lines. But using ticker veneers should lead to a deterioration of final products mechanical properties. To quantify this effect, we have made 20-21mm thick LVL (Laminated Veneer Lumber) boards of beech (Fagus sylvatica) with various compositions (veneers 1, 3 or 5 mm thick). In order to obtained veneers enclosing different grades, several bolts of a same tree have been peeled following 4 different modalities changing wood conditioning temperature (20 / 70°C) and pressure bar settings (bar acting or not). The quality of all the veneers has been quantified before gluing. In total, 12 sets of boards have been produced for non destructive and destructive mechanical tests. The main results of these exploratory experiments are: a quite low weakening of LVL mechanical properties when increasing veneer thickness. the non destructive prediction of MOE by vibration seems not so good on LVL with thick veneers, especially in the case of edgewise loading, probably because of the presence of important lathe checks. in some configuration, and especially when using thick veneers, it could be benefit to load LVL flatwise rather than edgewise. for the measurement of shear strength on LVL, the 5-point bending test increases its efficiency when increasing veneer thickness. To properly order in a hierarchy the different veneer criteria impacting on LVL mechanical properties, new tests should be repeated on different LVL boards homogeneous for given criteria of veneer quality. (Résumé d'auteur

Proteomic investigation of enzymes involved in 2-ethylhexyl nitrate biodegradation in Mycobacterium austroafricanum IFP 2173.

International audience2-Ethyhexyl nitrate (2-EHN) is a synthetic chemical used as a diesel fuel additive, which is recalcitrant to biodegradation. In this study, the enzymes involved in 2-EHN degradation were investigated in Mycobacterium austroafricanum IFP 2173. Using two-dimensional gel electrophoresis and a shotgun proteomic approach, a total of 398 proteins appeared to be more abundant in cells exposed to 2-EHN than in acetate-grown cells. This set of proteins includes multiple isoenzymes of the beta-oxidation pathway, two alcohol and one aldehyde dehydrogenase, as well as four cytochromes P450, including one CYP153 which functions as an alkane hydroxylase. Strain IFP 2173 was also found to contain two alkB-like genes encoding putative membrane-bound alkane hydroxylases. RT-PCR experiments showed that the gene encoding the CYP153 protein, as well as alkB genes, were expressed on 2-EHN. These findings are discussed in the light of a recently proposed 2-EHN degradation pathway involving an initial attack by an alkane hydroxylase and one turn of beta-oxidation, leading to the accumulation of a gamma-lactone as a dead-end product

Experimental study of locally loaded timber in compression perpendicular to the grain

Since the test method for compression strength perpendicular to the grain was changed from a partial area to a full area loading test, strength values for softwood in EN 338 were significantly reduced. Consequently, a change in Eurocode 5 was necessary to ensure an equivalent resistance level in compression perpendicular to the grain. Experimental results are presented with wood in compression perpendicular to the grain. A numerical model is also presented. This model was used to establish a rule of calculation proposed at the P21A-Committee of the technical and construction equipment standardization office (BNTEC)

Correlation between Radial Variation and Mechanical Properties of Laminated Veneer Lumber made from 14 Poplar Cultivars

France is poplar largest producer in Europe. Most of companies have a very specialized raw material supply chain since they use almost one type of cultivar for their specific products. For example, I-214 is very suitable for light packaging, consider as exclusive raw material in all industries. However, to prevent companies from a potential disease of their unique raw material, we need to find alternative cultivars. 14 cultivars were then characterized in terms of material, mechanic, peeling, wood pulp properties in a collaborative project (CNPF-IDF, FCBA, INRA, ENSAM). As common knowledge, juvenile wood had lower mechanical properties than mature wood. In this research, we gave information about mechanical properties of LVL made from juvenile and supposed mature veneers from 14 poplar cultivars. Its objective was to classified veneer poplar cultivars into two categories: suitable for structural purposes and non-structural purposes. From each cultivars (theirs ages were 13-19 years old), we took two logs, then we peeled into 3 and 5.2 mm thick veneers. We separated veneers that resulted from sapwood and heartwood to produce LVL panels mostly performed with juvenile wood or “more mature” wood. The veneers were glued using polyvinylacetate (PVAC). The boards were then cut into standardized samples (21*21*500 mm) for mechanical tests, i.e. four points bending tests (1280 samples). Before these tests, nondestructive measurements of the MOE have been made on the bending samples using the BING method (vibration tests). The results showed that correlation between destructive and non-destructive test was 0.79 (it means nondestructive test could be used as reference to estimate MOE). Based on non-destructive test, poplar cultivars which were categorized for potential structural purposes, were: Brenta, Lambro, Soligo and Taro. The rest of poplar cultivars (A4A, Alcinde, Dvina, I-214, Koster, Lena, Mella, Polargo, Trichobel and Triplo) were categorized in non-structural. Also we found, there was a significant effect of juvenility for each cultivar . Sample taken from each veneer constituting panels were taken to measure the Micro Fibril Angle. The next step is to analyze the effect of MFA on mechanical characteristics of the panels for different cultivarsThe research was carried out with the use of equipment funded by the French National Agency for Research under the program "Investments for the Future" (ANR-10-EQPX-16