五軸工具機加工之非線性誤差刀具路徑規劃

製造業如航太、模具廠等，常常需要加工曲面複雜且精度高的產品，使用傳統的三軸工具機加工複雜曲面，經常會因重複定位而導致精度誤差，且必須考慮夾治具設計與製造的成本，若使用五軸工具機來加工這些產品，可以有效解決以上問題，因此使用五軸工具機加工精密零件已成為目前的趨勢。五軸工具機相對於傳統三軸工具機增加了兩個旋轉軸，使加工更靈活，也因此旋轉軸的精度對加工零件的影響也較深遠，其中因旋轉軸不連續所造成的非線性誤差及奇異點，容易造成切削出來的刀具路徑產生扭曲現象，破壞工件表面及造成工具機劇烈震動，傷害工具機，因此對於奇異點及其附近的非線性誤差的探討，成為重要的課題。本論文針對奇異點及其附近區域之非線性誤差做討論，利用弦高誤差判斷準則，再使用線性插補的方式將刀具路徑檔做線性插補，經由後處理轉換為數值控制程式，規劃其旋轉軸的連續性，並探討奇異點與非線性誤差在構型不同之工具機上所發生之情況及其關聯性，判斷在不同構型工具機上會發生奇異點的位置及現象，並將弦高誤差判斷的線性插補方式應用在不同工具機上，修正非線性誤差之現象。

關鍵字

奇異點；非線性誤差；插補；弦高誤差

並列摘要

Manufacturing industries such as aerospace, mold factory, etc., often require machining complex surfaces and high precision products, using the traditional three-axis machine tool machining complex the surfaces, often result in repeated positioning precision error, and must consider cost in the design and manufacture of fixtures；the use of five-axis machine tools to process these products can effectively solve the above problem, that is to say, use of the five-axis machine tool machining precision parts has become the current trend. 5-axis machine tool has two more rotary axes relative to the traditional three-axis machine tools, so that its machining processing capability is more flexible, and thus the rotation axis has more influences on precision machining parts due to nonlinear error and the singular point. This is likely to cause the cutting tool path distortions, damage the surface and cause the severe vibration of the machine tool to damage the machine tool, and therefore the study of the singular point and its adjacent nonlinear error have become important issue. This paper presents a discussion on a singular point, its non-linear error, and their relationship in various types of machine tools. Based on chord error assessment, we interpolated a tool path by using linear interpolation to modify the problems that non-linear errors produce. We obtained an NC code by using a post processor that we developed and by evaluating tool path manufacturing continually. In addition, we confirmed where the singular point occurs, as well as its influence on various types of type machine tools.

並列關鍵字

Five-axis machining ； Numerical control ； Tilted plane ； Machining feature.

參考文獻

[1] D. N. Reshetov, V. T. Portman, 1998, “Accuracy of Machine Tool”, ASME press, New York.

Google Scholar

[2] Y. Takeuchi, T. Watanabe, 1922, “Generation of 5-axis Control Collision-Free Tool Path and Postprocessing for NC Data”, Annals of the CIRP, Vol. 41, No. 1, pp.539-542.