Geometrical Analysis and Optimization of 5-Axis Milling Processes

Official URL: http://risc01.sabanciuniv.edu/record=b1161888 (Table of Contents)

5-axis milling processes are widely used in industries where complex surfaces are machined, and cutter accessibility is limited due to geometrical constraints on the workpiece. Additional motion capability increases the accessibility of the cutting tool, so it becomes possible to machine complex surfaces despite the geometrical constraints. In most of these industries dimensional tolerance integrity, surface quality, and productivity are of great importance. Therefore, identification of optimal or nearoptimal process conditions, and selection of appropriate machining strategy for a given workpiece are required. Increased motion capability in 5-axis complicates the geometry and the mechanics of the process. Thus, optimization of 5-axis milling processes becomes a complex engineering problem. In order to solve such a problem, process models should be used together with geometrical analysis methods. In selection of appropriate machining strategy, surface characteristics should be known together with the process mechanics. In this thesis, a complete geometrical model is presented for 5- axis milling processes using ball-end mills. The developed model is integrated with an existing 5-axis process model in order to simulate the cutting forces throughout a given toolpath. Also, the effect of lead and tilt angle pair on process mechanics is investigated, and optimized values of those under various conditions are identified. In addition, a model suggesting the most appropriate strategy among various machining strategies for roughing and finishing operations for regular free form surfaces is presented. The developed models are verified through experiments and their applications are demonstrated on complex surfaces.