| Summary: | 碩士 === 國立中正大學 === 機械工程系研究所 === 106 === Since CNC machine tools with rotational tables were invented, the manufacturing of dies and plastic molds have been growing up rapidly. At the same time, the requirements of machining accuracy become higher and stricter. In order to meet the requirements, the indicator for measuring the quality of machining is very essential. Generally, the tool tip contour error and the tool orientation error are the main indexes for indicating the accuracy of machining. However, both of indexes are normally modeled separately which cannot illustrate the effect of the tool orientation error on the position contour error. In other words, the additional overcut that caused by the tool orientation error cannot be investigated if both indexes are not considered together. Therefore, the new indicator, the total contour error, is proposed in order to consolidate both tool tip contour error and tool orientation error into one term. The analytical solutions of total contour error for a simple simultaneous three-axis motion with tilting table is primarily introduced and validated through simulations. Then, a concept of total contour error and its analytical solutions are applied to pre-compensation approach and online compensation approach for reducing total contour error. The advantage of using proposed compensation approaches is it can directly reduce total contour error without compensating errors in rotational axis. It means the tool orientation error is already compensated in term of position, which is simpler than the conventional compensation approach that needs to compensate both of tool orientation error and tool tip contour error individually. In this thesis, the proposed methods are verified on a tilting rotary table type five-axis machine tool. The experiments show that the proposed pre- and online compensation approaches can significantly deduct total contour error even though tool orientation error still remains.
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