多軸工具機之體積誤差檢測系統與微細銑削精度提升技術之研究

The Study of the Volumetric-Error Measurement System for Multi-Axis Machine Tools and the Accuracy Enhancement for Micro-Milling

游涵任(Han-Jen Yu)

指導教授 ： 王世明

中原大學/工學院/機械工程研究所/博士(2008年)

https://doi.org/10.6840/cycu200800134

摘要

工具機一直為生產製造設備的主流，因為科技產品的演進及環保考量，工具機的加工需求逐漸朝向微型化、超精密方向發展。提升工具機的加工精度，除了硬體上的改善外，精確的誤差檢測及補償方法的提出也相當重要。有鑑於此，針對一般尺寸五軸工具機與微型工具機的加工特性，本研究發展了一系列的誤差量測及補償方法。
五軸工具機較三軸工具機除了原有的x-y-z三軸向傳動驅動外，另外增加了兩軸向的旋轉驅動，因此體積誤差除了三軸向的總位置誤差外，亦包含了兩軸向的旋轉誤差。針對業界常見的三類型五軸工具機 (RRTTT、TTTRR及RTTTR)，研究中利用低成本的循圓測定儀作為檢測設備，並配合單磁座法、兩階段量測法及推導的旋轉誤差模型來發展五軸工具機的體積誤差量測法。同時，也提出以Element free method誤差預測法，藉由內揷有限點的體積誤差來對刀具加工位置進行誤差預測，並配合誤差補償及自動NC碼辨識與編譯系統來修正NC碼路徑，以提高機器加工精度的方法。
精微加工的研究發展已是國際潮流，然而有效的誤差檢測方法仍缺乏，本研究利用機械視覺技術發展機上高精度檢測系統，以非接觸方式來檢測精微加工的誤差。機上高精度檢測系統分為兩部份：(1) 2D輪廓誤差檢測系統；(2)深度檢測系統。機上2D輪廓誤差檢測系統利用邊緣偵測法、座標轉換、誤差辨識法及影像匹配原理發展機上2D輪廓誤差檢測系統，其優點是可於機上直接量測微型工件的平面輪廓誤差及循跡誤差。機上深度檢測法則是藉由建立新深度量測模型與方法，克服了一般影像檢測於z軸向量測不精確的缺點。藉由二階段相機旋轉的檢測方式及新深度量測模型，可進行高精度的工件深度檢測。
經由數值的模擬與實機的驗證，證實了論文中發展的方法及系統確實能進行高精度誤差檢測，且配合NC碼修正補償的方式能確實提升加工精度。

關鍵字

精微加工 ； 加工精度 ； 機械視覺 ； 體積誤差 ； 誤差補償

並列摘要

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.

並列關鍵字

error compensation ； machining accuracy ； machine vision ； volumetric errors ； micro machining

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