Comparative study of tools in drilling composites T700-M21 and T800-M21

The drilling of composite materials can produce, around the hole, defects and damages which decrease the mechanical resistance of the drilled workpiece. This study shows the influence of several tools (drill, mill and reamer) on the hole quality obtained, in the context of reference parts where surface integrity is a priority. An experimental study is suggested and the criteria used to assess the hole quality are defined. Results show the behavior of each type of cutting tool and their influence on the defects generated. Finally, this study helps creating a scale of recommended cutting conditions to reduce the tool wear and improve the hole quality

Ponts mixtes bois béton collés: Etude de l’interface sous chargement thermo-hygromécanique

Dans ce papier sont présentés les premiers résultats d’une étude globale visant à consolider, puis proposer des règles de dimensionnement de ponts mixtes bois / béton collés. La liaison collée est explorée de manière expérimentale avec des essais de cisaillement utilisant du lamellé collé et du LVL. Afin d’anticiper le vieillissement de cette liaison, des essais ont été réalisés à différentes humidités. Dans une deuxième partie, le développement d’outils de simulation par éléments finis est présenté. La modélisation thermo-hydrique est appliquée sur des temps longs à des sections correspondant aux nervures bois d’un pont. Les phénomènes mécaniques à prendre en compte sont listés.Conseil Régional Bourgogne Franche-Comt

The effect of log heating temperature on the peeling process and veneer quality: beech, birch, and spruce case studies

Heating green-wood prior to peeling is necessary to improve both peeling process and quality of veneer. This study investigates optimum heating temperatures by soaking of beech, birch and spruce. Experiments have studied the influence of heating temperatures from 20 to 80 C on thickness deviations and veneer lathe checking using a pneumatic rugosimeter and image analysis of opening checks with the SMOF device (Système de Mesure de l’Ouverture des Fissures). Conclusions account for reduced heating temperatures compared to the temperatures currently in-use in the industry. Already at 50 C, positive effects of heating ensure efficient peeling process. Low temperatures produce veneers with deeper and more spaced checks than high temperatures when checks are closer and less deep, becoming even unpredictable especially in case of spruce. These results establish the SMOF as an essential non-destructive control device to control the quality of the veneer produced at research level.Institut Carnot, RYM-TO Doctoral Schoo

Wood machining with a focus on French research in the last 50 years

International audienceContext: Woodcutting is a very old technology but scientific research is scarce on the subject. In the last 50 years much work on basic mechanisms as well as industrial processes has been done in France. Aims: The specific nature of wood introduces strong differences between wood and metal cutting processes. The paper focuses on French teams' contributions. Results: The basic aspects of the tool–material interaction for different basic modes in woodcutting are highlighted. In primary conversion such as sawing, veneer cutting or green wood chipping, huge progress comes from automation and the possibility of linking the process to log and product quality through new sensors. In secondary processing much has been done on the links between the cutting process, surface qualification and the properties of these surfaces for further processing, such as gluing or coating. Tool wear depends on the cutting process, timber quality, and species. Trade-offs are required in tool technology and coating technologies may improve tool life. Conclusion: A large amount of knowledge and innovation has come from 50 years of worldwide research effort, with France being particularly active in this period. The transfer of skills from metals cutting industry was often a key, but much is needed to move closer to both metal cutting sector and woodcutting skills among craftsmen