MEASURING CUTTING FORCES IN ROUTING WOOD AT VARIOUS GRAIN ANGLES STUDY AND COMPARISON BETWEEN UP- AND DOWN- MILLING TECHNIQUES, PROCESSING DOUGLAS FIR AND OAK

In the framework of a research dealing with surface quality and surface formation mechanics some specimens of Douglas fir and Oak have been routed at different grain angles with a 3axis routing machine, with up- and down-milling techniques. Cutting forces have been measured by a tri-axial dynamometric platform, an interpretation of their behaviour is proposed and the different processes have been studied and compared. The results of our study show the behaviour of parallel and normal force, as an influence of the grain angle, and give a geometrical explanation. Comparison of data from up- and downmilling shows how cutting forces are influenced by cutting geometry, and consequently the main differences between these two techniques. Data of Douglas fir and Oak are compared as well two different depths of cut for Douglas fir.