[[alternative]]Investigation of the effect of cobalt concentration on the grindability of cemented carbide

碩士[[abstract]]玻璃模造製程（GMP）在大量生產高精度光學元件，如球面及非球面玻璃透鏡及自由曲面光學元件，是非常具有前景的一項技術。然而，只有極少數的材料可以承受在玻璃模造成形時，產生的化學反應、機械應力及高溫等影響，而這類的模具材料大多是難加工的材料。致使要將這類的材料加工到次微米等級的形狀精度及奈米等級的表面粗糙度是相當困難且耗費成本。而在可選擇的材料為數不多的情形下，碳化鎢(WC)是目前業界最常應用於玻璃模造的模具材料之一。碳化鎢，是由碳化鎢與結合劑鈷燒結成的材料，為碳化鎢顆粒及鈷結合成的複合材料。鈷含量對於碳化鎢的機械性質扮演著很重要的角色。因此本研究的目的為探討不同鈷含量對於碳化鎢的磨削特性之影響。而本研究所選用的加工參數為主軸轉速、切削深度與進給，了解此加工條件對加工後表面所造成的影響。研究發現，較低的鈷含量其碳化鎢有著較高的硬度值及較佳的表面粗糙度(Ra)。在本研究中，鈷含量0%至3%的碳化鎢其表面粗糙度值可達到5nm，其結果優於鈷含量6%至13%的10nm。[[abstract]]Glass molding process (GMP) is regarded as a very promising technique for mass producing high precision optical components such as spherical/aspheric glass lenses and free-form optics. However, only a handful of materials can sustain the chemical reaction, mechanical stress and temperature involved in the glass molding process and almost all of these mold materials are classified as hard-to-machine materials. This makes the machining of these materials to sub-micrometer form accuracy and nanometer surface finish a rather tough and expensive task. Amongst those handful choices, tungsten carbide (WC) is by far the most commonly used mold material in GMP industry. WC, also known as sintered/cemented WC with cobalt (Co) binder, is a metal matrix composite of WC particles and Co matrix. Cobalt concentration plays an important role in shaping mechanical properties of the obtained WC/Co materials. This research aimed to investigate the effect of Co concentration on the grindability of WC/Co materials. Efforts have been made to correlate grinding parameters such as spindle speed, cut depth and feed to the obtained surfaces. It is found that, despite of higher hardness values, better surface finish can be achieved on WC/Co specimen of lower Co concentration. In the present study, surface roughness (Ra) values better than 5nm and 10nm were obtained on WC/Co specimens of 0~3% and 6~13% Co concentrations respectively.[[tableofcontents]]目錄 致謝 ................................. I 中文摘要...........................II 英文摘要...................................III 目錄 ............................................ V 圖目錄 ................................... VII 表目錄 ...................................... X 第一章緒論...............................................1 1-1 前言.................................................1 1-2 研究背景.............................................2 1-3 研究動機與目的.......................................5 第二章 文獻回顧與理論基礎................................6 2-1硬脆材料特性..........................................6 2-1-1碳化鎢..............................................6 2-2 表面粗糙度分析.......................................9 2-2-1 表面組織定義.......................................9 2-2-2 定義表面粗糙度的方法..............................11 2-3 壓痕探討............................................12 2-3-1 壓痕理論探討......................................13 2-3硬脆材料製造方法.....................................18 第三章 實驗設備與實驗步驟...............................23 3-1 實驗目的............................................23 3-2 實驗規劃............................................23 3-3實驗流程圖...........................................24 3-4 實驗設備與方法......................................25 3-4-1 加工材料..........................................25 3-4-2 砂輪、加工參數....................................25 3-4-2 超精密加工機......................................26 3-4-3 微硬度機..........................................28 3-4-4 雷射共軛焦顯微鏡..................................28 3-4-5 光學顯微鏡........................................30 3-4-6 掃描式電子顯微鏡..................................30 3-4-7 切削油............................................31 第四章 結果與討論.......................................32 4-1壓痕實驗.............................................32 4-1-1 WC-Co硬度值實驗...................................32 4-1-2 WC-Co破裂韌性 .....................................34 4-2磨削加工參數選擇與表面分析...........................36 4-2-1不同進給量影響 .....................................36 4-2-2不同切削深度影響...................................48 4-2-3不同含鈷量的碳化鎢影響.............................58 4-3不同含鈷量碳化鎢工件移除量與砂輪磨耗實驗.............59 4-3-1 凹痕實驗..........................................59 4-3-1角度磨削研究.......................................61 4-3-1磨削比實驗.........................................65 第五章 結論.............................................67 參考文獻................................................69 圖目錄 圖1-1光學透鏡熱壓成形流程圖................................1 圖1-2光學透鏡模具模具與光學透鏡成品........................3 圖1-3砂輪磨耗及破裂模式結構圖..............................5 圖2-1碳化鎢結晶組成........................................7 圖2-2碳化鎢微結構圖........................................8 圖2-3具有相同不規則高度但間隔不同之表面....................9 圖2-4粗糙度及波紋所形成的表面.............................10 圖2-5表面外形代表粗糙度、波紋及形式.......................11 圖2-6Ra與Rq示意圖.........................................12 圖2-7波峰與波谷最大高度示意圖.............................12 圖2-8壓痕實驗.............................................15 圖2-9微壓痕產生中央、徑向裂痕與橫向裂痕示意圖.............16 圖2-10磨削脆性材料產生延性磨削機制........................19 圖2-11刀具與工件接觸結果示意圖(a)傳統切削(b)磨削(c)超精密加工(d)刮痕滑動.............................................19 圖2-12加工示意圖..........................................20 圖2-13磨削陶瓷材料時的熱量分佈............................22 圖3-1實驗規劃流程圖.......................................24 圖3-2碳化鎢工件...........................................25 圖3-3NACHi ASP01超精密加工機..............................26 圖3-4超精密加工示意圖.....................................27 圖3-5微小維克氏硬度試驗機FUTURE-TECH FM-300e..............28 圖3-6雷射共軛焦顯微鏡 Keyence VK-9700.....................29 圖3-7 Olympus BX51M 光學顯微鏡............................30 圖3-8掃瞄式電子顯微鏡HITACHI S-2600H......................31 圖3-9場發射掃瞄式電子顯微鏡 LEO 1530 FE-SEM...............31 圖4-1加工示意圖...........................................32 圖4-2微壓痕菱形D1與D2量測示意圖...........................33 圖4-3硬度值折線圖.........................................34 圖4-4微壓痕產生橫向裂痕與量測示意圖.......................35 圖4-5橫向裂痕長度垂直方向與平行方向影響...................36 圖4-6加工參數與加工位置...................................37 圖4-7進給量對WC-Co表面粗糙度影響Ra(切深=1.5μm)...........38 圖4-8不同進給量對WC-Co0%表面粗糙度影響(a)f=2μm/rev.、(b)f=5μm/rev.與(c)f=10μm/rev..................................39 圖4-9不同進給量對WC-Co6%表面粗糙度影響(a)f=2μm/rev.、(b)f=5μm/rev.與(c)f=10μm/rev..................................41 圖4-10不同進給量對WC-Co13%表面粗糙度影響(a)f=2μm/rev.、(b)f=5μm/rev.與(c)f=10μm/rev...............................43 圖4-11粗糙度值示意圖......................................44 圖4-12WC-Co0%，(a)(b)f=2μm/rev.、(c)(d)f=5μm/rev.與(e)(f)f=10μm/rev.之SEM圖與OM圖.................................45 圖4-13WC-Co6%，d=1.5μm，(a)(b)f=2μm/rev.、(c)(d)f=5μm/rev.與(e)(f)f=10μm/rev.之SEM圖與OM圖...................46 圖4-14WC-Co13%，d=1.5μm，(a)(b)f=2μm/rev.、(c)(d)f=5μm/rev.與(e)(f)f=10μm/rev.之SEM圖與OM圖...................47 圖4-15切削深度對WC-Co表面粗糙度影響Ra(進給=2μm/rev.).....48 圖4-16不同切削深度對WC-Co0%表面粗糙度影響(a)d=0.3μm、(b)d=0.7μm與(c)d=1.5μm.....................................50 圖4-17不同切削深度對WC-Co6%表面粗糙度影響(a) d=0.3μm、(b) d=0.7μm與(c)d=1.5μm.....................................52 圖4-18不同切削深度對WC-Co13%表面粗糙度影響(a) d=0.3μm、(b) d=0.7μm與(c)d=1.5μm.....................................54 圖4-19WC-Co0%，f=2μm/rev.，(a)(b) d=0.3μm，(c)(d)d=0.7μm，及(e)(f)d=1.5μm之SEM圖與OM圖..........................55 圖4-20WC-Co6%，f=2μm/rev. (a)(b) d=0.3μm，(c)(d)d=0.7μm，及(e)(f)d=1.5μm之SEM圖與OM圖.............................56 圖4-21WC-Co13%，f=2μm/rev. (a)(b) d=0.3μm，(c)(d)d=0.7μm，及(e)(f)d=1.5μm之SEM圖與OM圖..........................57 圖4-22不同鈷含量碳化鎢工件比較(切深=0.7μm)...............58 圖4-23凹痕實驗加工示意圖..................................59 圖4-24相同切削深度的移除截面圖WC-Co(a)0%(b)6%(c)13%.......60 圖4-25磨削角度示意圖......................................61 圖4-26磨削加工位置示意圖..................................61 圖4-27碳化鎢工件Level 0動作表示...........................62 圖4-28Level 0要求精度.....................................62 圖4-29磨削角度45°之橫截面.................................63 圖4-30磨削角度45°砂輪磨耗示意圖...........................63 圖4-31磨削角度15°之橫截面.................................63 圖4-32磨削角度15°砂輪磨耗示意圖...........................64 圖4-33磨削角度75°之橫截面.................................64 圖4-34磨削角度75°砂輪磨耗示意圖...........................65 圖4-35磨削比..............................................66 表目錄 表3-1磨削加工參數.........................................25 表3-2超精密加工機NACHi ASP01規格表........................27 表3-3雷射共軛焦顯微鏡 Keyence VK-9700規格表...............29 表4-1WC-Co硬度量測值......................................33 表4-2加工參數與分析結果...................................35[[note]]學號: 698371365, 學年度: 10