[[alternative]]The Dynamic Structure Characterization Analysis and Redesign of Gantry Machine

碩士機電工程學系[[abstract]]近年來產品開發期的縮短及創意思考產品不斷受重視，成本及時間效益也須跟著縮短。桌上型CNC工具機被視為發展的重點，結構剛性不良會使得加工時發生不穩定的振動。本研究探討桌上型龍門工具機之結構動態特性，藉由有限元素分析及模態實驗測試了解動剛性、共振頻率、模態振型、阻尼比。經由模態實驗我們發現，桌上型龍門工具機工作平台剛性與底座接合面需要加強。對平台改善及設計一新型平台，原先所設計之平台對整機有區域共振現象，並驗證平台對整機之影響，將有限元素分析與實驗結果作為日後新機型開發的主要依據。[[abstract]]In recent years, down size product and creative features have been paid more and more attention. Cost effective for such manufacturing is very important. The desktop CNC machine is treated as the main stream for mechanical engineering. Low stiffness of the structure causes the unstable vibration during the processing. In this thesis, we investigate the dynamic characterization of the gantry type machine. Dynamic stiffness, natural frequency, mode shapes, and damping ratio of the table CNC machine are discussed via the finite element analysis and modal testing experimentally. By the modal testing experiment result, the platform stiffness and the junction behavior between the base and the platform is examined. A new platform is created for overcoming the local resonance of the machine. This thesis builds some knowledge for remodeling the base plate by the finite element analysis. Experimental implementation for bettering stiffness will be done in the future