廖運炫臺灣大學：機械工程學研究所陳宇杰Chen, Yu-ChiehYu-ChiehChen2007-11-282018-06-282007-11-282018-06-282005http://ntur.lib.ntu.edu.tw//handle/246246/61287以碳化鎢鑽頭鑽削鎳基超合金Inconel 718，至今沒有提升切削效率的對策，本文由分析鍍層鑽頭的破壞模式，提出相對應之改善方案。實驗發現四個階段的破壞機制中，刀具與材料間過大之摩擦應力為主要因素，不但引發鍍層脫落及刃口積屑(BUE)形成，同時提供材料內部裂紋成長能量，造成切削刃邊的斷裂，次要原因則為韌性之長連續屑發生，引起更大之刀具破壞。 研究中加入奈米尺寸碳氫分子顆粒組成之奈米切削液，發現能有效降低鑽削推力及扭矩，延長刀具壽命三倍。其作用機制有二，一為鑽槽邊切屑-刀具之滑動區域及刀腹邊刀具-工件接觸區域，加工中奈米顆粒深入金屬表面，附著並形成薄膜，避免了金屬與金屬間之直接接觸摩擦，緩和鑽頭破壞。另外則是提供鑽槽區域較低摩擦之切屑流動，排屑更為順暢。同時以奈米切削液配合未鍍層刀具使用，在相同的加工條件下，可以大幅減少生產成本。 本研究自行設計並改裝一超音波壓電振動子與工具機刀具夾頭相互結合，完成由鑽頭刀具端振動之加工方式。應用超音波振動輔助鑽削，縮減了屑的尺寸，亦增加了碎屑產生的比例，有效抑制鑽削末期不穩定之扭矩變化。振幅較頻率對鑽削壽命影響為大，實驗歸納出最佳組合之31.8 KHz頻率及4 μm振幅超音波參數，可得到最佳的鑽削結果。深孔加工時，以超音波振動輔助模式可以取代啄鑽提刀設定，可節省1/3的加工時間，有效增進加工效率。The fracture mechanisms and the approaches to prolong the service life of the coated carbide tool in drilling Inconel 718 superalloy are presented. Four fracture stages are identified in this study. The extra friction between the tool-workpiece interfaces results in the abrasion of the coated layer is the major cause of drill fracture. The BUE is formed and subsurface fatigue cracks are initiated and grow sequentially. Eventually the cutting edge near the periphery is damaged. Therefore, long and thick chip forms leading to unstable drilling force and flank wear is worsened as a result. Drilling experiments with the use of the nano cutting fluid containing the hydrocarbon molecule are conducted. It is found that the service life of the drill is lengthened significantly and drilling force is decreased. EDAX is taken to identify the constituents on the sliding region of chip-tool interface and contacting region between the tool flank and workpiece. It is found that nano particles are deeply adsorbing and may react with the metal surface. A layer forms to avoid the direct contact between the drill and the workpiece. In addition, less friction coefficient for chip flow is obtained on the drill flute region when nano cutting fluid is applied. It is also noted that the use of uncoated carbide drill with nano cutting fluid results in an even better drill life as compare with that resulting from traditional drilling. The tool holder of a machining center is retrofitted so that a piezoelectric driven ultrasonic vibration oscillator can be integrated to produce axial harmonic vibration during drilling process. The ultrasonic vibration assisted drilling is applied to eliminate the cutting resistance from long chips. Experimental results show that the chip size is reduced, and the variation of torque in drilling becomes smaller. It is also found that there is little improvement in drilling performance when the frequency of the ultrasonic vibration is varied. On the contrary, a drill’s life is greatly increased by controlling the amplitude of the vibration. The frequency of 31.8 KHz and the amplitude of 4μm result in the best drill life and quality of the drilled hole. Concerning drilling efficiency, it is found that by applying ultrasonic vibration assisted drilling, lifting of the drill in conventional drilling of a high aspect ratio hole is not necessary, and saving one-third of the working time is obtained.中文摘要 ………………………………………………………………… I 英文摘要 ………………………………………………………………… Ⅱ 目錄 ……………………………………………………………………… IV 圖目錄 …………………………………………………………………… VII 表目錄 …………………………………………………………………… XII 符號說明 ………………………………………………………………… XIII 第壹章、導論 ………………………………………………………… 1 1.1 研究動機 ……………………………………………………………… 1 1.2 文獻回顧 ……………………………………………………………… 4 1.3 研究目的 ……………………………………………………………… 9 1.4 論文架構 ……………………………………………………………… 10 第貳章、相關理論 ………………………………………………… 11 2.1 鎳基超合金Inconel 718 …………………………………………… 11 2.1.1 材料組成 ……………………………………………………… 11 2.1.2 強化機構及切削性 …………………………………………… 17 2.2 鑽削加工 ……………………………………………………………… 21 2.2.1 鑽頭形狀 ……………………………………………………… 21 2.2.2 鑽尖與鑽腹對鑽削作用的影響 ……………………………… 22 2.2.3 鑽頭分類 ……………………………………………………… 26 2.3 刀具破壞理論 ……………………………………………………… 28 2.4 奈米顆粒基本性質 ………………………………………………… 33 2.5 超音波理論 ………………………………………………………… 38 2.5.1 超音波振動子 ………………………………………………… 39 2.5.2 振幅喇叭之設計 ……………………………………………… 43 第參章、實驗方法及設備 ………………………………………… 45 3.1 實驗方法 …………………………………………………………… 45 3.1.1 鑽頭破壞機制推導 …………………………………………… 47 3.1.2 加工參數最佳化 ……………………………………………… 47 3.1.3 奈米切削液對鑽削加工之影響 ……………………………… 48 3.1.4 超音波振動輔助鑽削對加工之探討 ………………………… 50 3.2 實驗設備名稱及詳細規格 ………………………………………… 51 第肆章、鑽削參數最佳化與鑽頭破壞機制 ………………… 55 4.1鑽削參數最佳化 …………………………………………………… 55 4.1.1 鑽尖角與餘隙角對鑽頭破壞之影響 ………………………… 55 4.1.2 鑽尖角與餘隙角對鑽頭壽命之影響 ……………………… 61 4.2 鑽頭破壞機制 ………………………………………………………… 65 4.3 小結 ………………………………………………………………… 73 第伍章、奈米切削液應用於鑽削加工之研究 ……………… 74 5.1 奈米切削液 ………………………………………………………… 74 5.2 添加奈米切削液對於鑽削之影響 ………………………………… 76 5.3 小結 ………………………………………………………………… 87 第陸章、超音波振動輔助鑽削加工Inconel 718 ………… 88 6.1 振動機構的設計 …………………………………………………… 88 6.2 超音波振動輔助鑽削與一般鑽削之比較 ………………………… 94 6.3 振幅與頻率對於鑽削之影響 ……………………………………… 99 6.4 超音波振動輔助鑽削與啄鑽加工之比較 ………………………… 103 6.5 小結 ………………………………………………………………… 106 第柒章、結論與未來展望 ……………………………………… 107 7.1 結論 ………………………………………………………………… 107 7.2 未來展望 …………………………………………………………… 109 參考文獻 ……………………………………………………… 1113715190 bytesapplication/pdfen-USInconel 718鑽削加工奈米切削液超音波振動輔助鑽削drillingnano cutting fluidultrasonic vibration assisted drillingthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/61287/1/ntu-94-D88522022-1.pdf