A Study on Improving Cutting Stability Lobe Based on Machining Data

切削是機械加工中非常重要的一個步驟，並被廣泛地用於製造產業。切削加工過程中影響常受切削時產生的顫振所困擾，切削顫振會造成刀具與工件間的相對振動，使得加工品質降低，甚至破壞加工設備，故如何避免切削顫振為一迫切的課題。雖然文獻提出諸多不同避免切削顫振的方法但大多不夠準確，本研究以敲擊實驗獲得之系統參數為參考，進行實際切削求得在不同轉速下的臨界切深，並且透過最小平方法進行系統的參數鑑別，求得在不同轉速下，系統參數的變化，並以此調整切削穩定圖，令使用者有其更精準的依據，以避開顫振。本研究探討之方法進一步在加工中心機以及CNC車床驗證銑削與車削之適用性，結果顯示以本方法調整之切削穩定圖可較精準地吻合加工數據。Cutting is one of the most fundamental machining processes and has been widely applied in industrial practice. While cutting is often bothered by chattering that generates vibration between the cutting tool and the workpiece thus downgrades the process quality and even damage the machine tools, it has been an issue how to overcome the chattering problem. Chattering is represented by the cutting stability lobe which indicates the limit of depth of cut for stable cutting at each spindle speed or cutting speed. Although various methods have been proposed to avoid the chattering in the cutting process, most of them are unable to predict the chattering precisely. In this study, cutting system parameters and stability lobe are improved based on machining data with system parameters obtained by modal testing as a reference. The machining data are the critical depth of cut at different cutting speeds. Cutting system parameters at different speed are calculated by least error square fit. Stability lobe is then adjusted based on the new system parameters. Two tests, a milling test and a turning test, are performed based on the proposed method for verification. The improved stability lobe is a good guide for engineers to avoid chattering目 錄 誌 謝 i 中文摘要 ii ABSTRACT iii 目 錄 iv 圖目錄 vi 表目錄 viii 符號表 ix 第一章 緒論 1 1.1緣起 1 1.2研究方法及步驟 2 1.3本文架構 3 第二章 文獻回顧 4 2.1切削振動分類 5 2.1.1自由振動 5 2.1.2強制振動 6 2.1.3自激振動 6 2.2切削顫振分析 8 第三章 切削穩定性分析 10 3.1 振動之數學模式 10 3.1.1自由振動數學模式 10 3.1.2強制振動數學模式 12 3.1.3自激振動數學模式 12 3.2切削穩定圖分析 14 3.2.1單自由度系統顫振分析 14 3.2.2多自由度系統顫振分析 18 第四章 切削顫振實驗 20 4.1可行性探討 20 4.2銑削實驗 23 4.2.1銑削實驗架設 23 4.2.2銑削實驗結果 27 4.3車削實驗 32 4.3.1車削實驗架設 32 4.3.2車削實驗結果 34 第五章 結論與未來展望 39 5.1結論 39 5.2未來展望 39 參考文獻 4