| Summary: | 碩士 === 華梵大學 === 機電工程學系 === 107 === There is a great demand for precision machining owing to the rapid development of aerospace, photonic and mold industries. Therefore, developing machine tools for the fabrication micro cutting tools and its related technologies are vitally important for precision machine tool industry. This study aims to develop a specific tabletop micro wire-EDM machine with machine-vision-based measurement for the fabrication of micro end milling tools. This machine tool contains a gantry-type granite mechanical structure, a four- axis motion control system, an oil-based iso-pulse generator, a wire transport system, a machine-vision-based system and a CNC system. The CNC system can implement the functions of four-axis synchronous motion control, closed-loop wire tension control and on-line machine-vision-based measurement by means of an IMP2 motion control card and a remote I/O card. A novel micro wire transport system has been presented based on wire spool with permanent magnet brushless DC motor and wind up reels with permanent magnet brushless DC motor. Dynamic model of the wire transport system and a closed loop wire tension control system were derived and analyzed. A PID controller was employed to investigate the dynamic performance of the closed-loop wire tension control system. Test results has shown that standard deviation and coefficient of variation of the closed-loop wire tension control system can be kept as 7.75 cN and 3.04 %, respectively compared with 12.18 cN and 4.8% provided by open-loop control. Experimental results demonstrate that a tungsten carbide micro end milling tool with a diameter of 300 m can be fabricated by this tabletop machine tool. Depth and width of cutting slit can be on-line measured by using the machine vision system. Compared to measurement results using tool microscope, measurement error can be controlled within 3 %.
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