| Summary: | 博士 === 中原大學 === 機械工程研究所 === 95 === Machine tool is the major manufacturing equipment for the industry. Because of the development trend of high-tech products and environment protection concern, miniaturization and ultra-precision have become important function requirements for machine tools. In addition to improvement of machine structure, effective error measurement and compensation method is essential to enhance machining accuracy of a machine tool. Thus, error measurement and compensation methods were respectively developed for regular-size 5-axis machine tools and micro machine tools in this study.
Comparing to a 3-axis machine tool, a 5-axis machine tool has two additional rotational axes. Therefore, its volumetric errors also include two rotation errors. With using magnetic ball-bar, a method integrating single socket method and two-step measurement algorithm was developed for measuring the volumetric errors for three types (RRTTT, TTTRR, and RTTTR) of 5-axis machine tools. Besides, a method consisting of using element free method to predict the position/orientation errors of a cutter and using recursive error compensation method and automatic NC-code identification and re-writing system to compensate the predicted errors was proposed to further enhance machining accuracy of a machine.
Although micro machining has become a popular international research topic, an effective error measurement and compensation method for micro milling machine is still missing. Thus, an on-machine and non-contact error measurement system implementing machine vision technology was developed for the micro machining. The system consists of two parts: (1) the 2-D contouring error measurement system; (2) the depth measurement system. The 2-D contouring error measurement system integrating the edge detection method, coordinate transformation method, error identification algorithm, and photo matching algorithm provides the advantage of directly measuring the contouring error and tracking errors of a workpiece on the micro-milling machine. Based on the new depth measurement model and the 2-step CCD-rotation method, the developed depth measurement system can provide better measurement accuracy rather than the ordinary depth measurement system.
The results of simulations and experiments have shown that the method and system developed in this study can effectively measure the errors of 5-axis machine tools and micro machine tools. Furthermore, those errors can be corrected to enhance machine’s machining accuracy through the developed error compensation methods.
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