Caractérisation des efforts de coupe de différentes essences de bois à l'aide de leurs paramètres mécaniques

For wood industries, a better knowledge of material behaviour during machining became an obligation for economical and productive reasons : with equipment adapted to manufactures needs. Woodworking machinery and tools manufacturers, as well as their users, urgently require reliable information on the main factors influencing wood cutting and above all on the magnitude of the force required to separate a chip, i. E the cutting force and its variations in different cases. In fact, the control of cutting forces during wood machining is something absolutely essential : to estimate wood behaviour and surface quality; to work in respect of tool capability; to optimised cutting conditions. However, today, to estimate cutting forces, a factor remains difficult to take in consideration : the influence of wood species. The aim of this study is to approach the influence of "the wood species" factor on cutting forces involved during machining, to give more precision to the relation. These investigations deals with the study of fourteen exotics wood species in the 90-0 cutting process. The influence of mechanical characteristics generally described in the literature and involved in this cutting process (hardness, tenacity, compression and shearing parallel to the grain) was studied and some formulations was obtained which allowed to estimate more precisely strains involved and general behaviour of wood during machining (with an explanation of more than 80% of the variation of cutting forces). These mechanical characteristics seems to be an easy solution to understand the general mechanical behaviour of each wood species studied during machining. In addition of this work, another method was used to estimate easily and quickly cutting forces involved during machining : Chardin's pendulum. Results obtained are promising but give less precision than mechanical parameters. Finally, in the fourth part of this memory, an application of all these results to the methodology of the Couple Tool Material (COM) was realised, and allowed to give more precision in the estimation of good cutting conditions and in the optimisation of machining parameters.