Date of Award
Doctor of Philosophy (PhD)
M. A. Elbestawi
Advances in the aerospace and automotive industry have led to the introduction of many new shapes with complex geometries. These shapes are typical of turbine blades, as well as molds and dies. The manufacturing of these geometries consists of automatic tool path generation for multi-axis computer numerically-controlled machining centers. The conformity of the manufactured geometry to the design requirements depends on several factors. These involve cutting tool selection, positioning of the cutting tool, as well as the avoidance of collision and gouging between the cutting tool and the workpiece. This dissertation presents a solid modeling-based approach for tool geometry selection, the simulation and optimization of five-axis tool path generation, as well as gouge and collision avoidance for manufacturing sculptured surfaces. A methodology for tool path generation and checking for the flank-milling of operation is also developed. An optimization algorithm is developed to re-distribute tool path points according to their effect on the geometry of the manufactured surface. A new algorithm to determine tool inclination is also developed based on an effective tool profile and curvature matching techniques. A cusp height control approach is developed based on feasible tool inclinations, and step-over distance evaluation. An algorithm for tool path generation and gouge as well as collision avoidance is developed. A flank milling tool path planning and checking algorithm is developed based on the optimization of the tool path advancement scheme according to the surface topology. A new multi-stage tool model refinement approach was developed, and integrated with the algorithms that constitute this work. Experimental validation of the presented algorithms is carried out to test the cusp height, and smoothness of the tool orientation transition. A comparison between the presented algorithms and state of the art CAM commercial software is also presented. The validation results showed that the developed approach can give more accurate results. The results of this work are intended to fill the shortcomings encountered in the previous research on five-axis machining of sculptured surfaces. These are: cutting tool selection; tool path points optimization, cusp height control, tool position and orientation optimization, and flank-milling.
Youssef, Amro M. Fikry, "Optimization of machining strategy and process planning of complex geometry" (2004). Open Access Dissertations and Theses. Paper 2859.