| Summary: | 碩士 === 國立交通大學 === 機械工程系所 === 103 === Micro drilling tool plays an extremely important role in many processes such as the printed circuit board (PCB) manufacturing process, machining of plastics and ceramics. The improvement of cutting performance in tool life, productivity and hole quality is always required in micro drilling.
In this research, a dynamic model of micro-drill tool is optimized by the interior-point method. To achieve the main purpose, the finite element method (FEM) is utilized to analyze the coupled lateral and torsional micro-drilling spindle system with the gyroscopic effect. The Timoshenko beam finite element with five degrees of freedom at each node is applied to perform dynamic analysis and to improve the accuracy of the system containing cylinder, conical and flute elements. Moreover, the model also includes the effects of continuous eccentricity, the thrust, torque and rotational inertia during machining. The Hamilton’s equations of the system involving both symmetric and asymmetric elements were progressed. The lateral and torsional responses of drill point were figured out by Newmark’s method.
The aim of the optimum design is to find some optimum parameters, such as the diameters and lengths of drill segments to minimize the lateral amplitude response of the drill point. Nonlinear constraints are the constant mass and mass center and harmonic response of the drill. The FEM code and optimization environment are implemented in MATLAB to solve the optimum problem.
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