Integrated precision machining and burr minimization in metals

In this dissertation, mechanisms of burr formation in drilling, milling and micro milling in metals are investigated. Based on the study, optimization and control of burr formation are developed. Parameter optimization for only minimization of burr formation could frequently deteriorate other machining performance, such as surface finish and tool life. Therefore, surface finish and tool life are also investigated with burr formation in this dissertation.; Burr measurement methods, the optical microscope method, optical CMM method, SEM and stylus, are summarized. SEM and stylus were successfully used for measuring micro burrs. Flag-type burr, rollover-type burr, wavy-type burr and ragged-type burr are observed in micro milling aluminum and copper. The rollover-type burr on tool entrance and flag-type burr on tool exit in micro milling are comparatively bigger than in the conventional milling process. Run-out in micro-milling causes a big wavy-type burr and form error. Experimental results obtained can be used in tool path planning and cutting condition selection for machining micro components.; A set of experiments designed to characterize surface quality for the micro-end-milling process have been performed. The effect of chip load, cutting speed, and depth of cut on surface roughness of aluminum (6061) samples was studied. The second order model was generated, and it predicts surface roughness reasonably well.; Micro-burr formation in cutting stainless steel was investigated according to various feed per tooth values and cutting speeds for a blind hole drilling process using a micro end-mill. For this experiment, tool life was defined as the number of holes created until a rapid increase of burr height was observed. Parameters, nuc, ft and ft/R were evaluated for micro-machining. Burr size and tool life can be predicted and controlled through the control charts developed. The same analysis approach is suitable for application with other materials and processes.; An internet-based Milling/Drilling Burr Expert System was proposed and their architectures were described in this dissertation.; An iterative DOE method to minimize burr formation and to improve surface roughness simultaneously in high-speed face-milling was proposed. This iterative DOE method was also applied to minimize burr formation in intersecting drilling holes. Using this method, dominant factors on burr formation and surface quality can be found and optimal cutting condition can be determined.