臺灣博碩士論文加值系統

放電銑削是製作模仁的新式加工法，但長時間放電加工電極損耗易導致加工尺寸不精準與模仁表面不平整，為此，過去產學各界衍生出許多放電補償方式。過去常見電極補償方式，採更換相同大小之電極。不過需費時校正長度、位置和儲備多支電極。隨後許多學者提出不更換電極之補償研究法，從調查補償深度與路徑規劃著手編寫程式，雖然其加工深度明顯改善；但底部形貌仍殘留缺陷，且隨加工時間與移除體積增大，程式補償的改善效果仍受限制。
為此，本文提出嶄新的電極補償方式，採創新設計之補償機構，包括工件升降平台，與平台上附設刀具電極修整器作為修整電極之工具；其次，本文利用平台上工件表面高度與修整後電極相對位置不變的特性，經定量修整電極磨耗端部，用於提升刀具電極幾何精確度與表面完整性，以確保修整電極後為平整表面及正確長度，以達高精度之加工應用。實驗規劃電極為直徑2、3和6 mm鉻銅棒，工件材料為SUS 430不鏽鋼，初步實驗以放電加工深度4 mm盲孔來評估放電補償機構之可行性與精確度，並與一般程式深度補償法做比較，其次進行放電銑削開槽加工與斜面模仁銑削。經實驗證實，本文提出的補償法在盲孔加工深度降低80%誤差，底部弧角半徑縮減約50%；而在10mm長4mm寬的放電銑槽入/出口之深度誤差、與圓角半徑誤差皆能降低90%以上。最後，經本修整補償法改善微小金字塔模仁之放電銑削，可得完整斜面與稜線並去除底部圓角；於尺寸2.0 mm公模仁邊長可使誤差134.02μm改善至0.03μm，且底部型貌比一般EDM更完整清晰。

Electrical discharge milling (milling EDM) is a new method for fabrication of mold cavity, but wear of tool electrode make depth error and uneven surface on workpiece. For this reason, many researchers study electrode compensation methods. In which, it is a common strategy in the past to replace with a same size of electrode from EDM spindle. But, changing tool electrode spends lots of time in correcting position and the expensive cost of fabricating multiple electrodes in advanced. In recent days, many scholars dedicated to electrode compensation without changing electrode. Although improving cavity’s depth error by tuning EDM parameters and tool path planning by programming are commonly seen, but the residual volume is still not removed at the cavity bottom, especially corners at the bottom. In this paper, a novel electrode dressing mechanism and wear compensation method are proposed. By designing a lifting platform on EDM tank, equipped with a tool dressing mechanism on the platform, the worn electrode is dressed to its original geometry. After such dressing, the damage electrode surface will be flatten and provided with accurate tool length. Another key feature is it can maintain the constant altitude between dressed tool tip and the workpiece surface in this method. Experimental electrodes adopts chromium-copper cylinder of diameters of 2, 3 and 6 mm, and workpiece adopts SUS430 stainless steel. First, EDM blind-hole with a depth 4mm is conducted to assess feasibility of the dressing compensation and comparison with that by traditional EDM and programmed compensation schemes. Experimental results showed that 80% of depth error and 50% of corner radius at the bottom of blind holes can be reduced by this compensation. Then, milling EDM test on grooves of 10mm long by 4mm depth are conducted. More than 90% of depth error and 90% of corner radius at bottom of groove can also be compensated. Finally, the novel compensation method is applied to EDM milling of a 3D pyramid mold cores in meso-scale. From experiment, this method not only removes the residual volume at bottom corners and reducing the length error from 134.02 μm to 0.03 μm for the square convex core of 2.0×2.0 mm, but also fabricates sharp crest line and inclined planes.

目錄
目錄 v
圖目錄 vi
表目錄 ix
符號說明 x
第一章 緒論 1
1-1前言 1
1-2文獻回顧 2
1-3研究動機與目的 10
1-4 本文架構 11
第二章 加工原理 12
2-1放電加工原理 12
2-1-1放電加工原理 12
2-1-2放電加工過程 13
2-1-3 放電加工參數 15
2-2電極補償 17
2-3放電補償構想 18
2-3-1 執行修整電極補償時機 19
2-3-2 結束修整電極補償時機 20
第三章 實驗設備與設置 22
3-1實驗設備 22
3-1-1放電加工機 22
3-1-2高速旋轉放電主軸 23
3-1-3變頻器 24
3-1-4電流探測棒 25
3-1-5差分探測棒 25
3-1-6表面輪廓儀 26
3-1-7表面粗度儀 26
3-1-8雷射顯微鏡 27
3-1-9量測示波器 28
3-1-10超音波清洗槽 28
3-2實驗材料-電極與工件 29
3-2-1工件 29
3-2-1電極 30
3-3創新放電補償機構之設計 31
3-4實驗架構圖 35
第四章 放電加工之修整電極補償 36
4-1主軸無旋轉放電銑削 36
4-2電極補償之放電加工比較 38
4-2-1電極修整方法 38
4-2-2主軸偏擺之影響 40
4-2-3刀具修整-盲孔放電加工之電極端面比較 44
4-2-4轉速對放電銑削之效應 46
4-3盲孔放電加工補償效益 48
4-3-1直徑3mm鉻銅棒盲孔EDM之形貌與面粗度比較 48
4-3-2直徑6mm鉻銅棒盲孔EDM之形貌與面粗度比較 54
第五章 放電銑削之修整電極補償 60
5-1直徑3mm電極放電銑槽補償 60
5-2 放電盲孔與放電銑削電極比較 66
5-4半自動化修整電極之放電加工應用 78
5-4-1半自動化修整電極之放電加工盲孔 81
5-4-2半自動化修整電極之放電銑槽 82
第六章 結論 83
參考文獻 85



















圖目錄
圖1-1放電加工均勻消耗法與加工路徑規劃 [1] 2
圖1-2放電加工電極補償法(a)均勻消耗(UWM) (b)均勻消耗結合線性補償(CLU) (c)掃描面積補償(BSA) [4] 3
圖1-3掃描加工路徑[4] 3
圖1-4 影像監控電極損耗底部[5] 4
圖1-5 (a)路徑規畫 (b)補償損耗值[6] 4
圖1-6 LDCA方法 [8] 5
圖1-7 (a)虛擬電極(b)改善表面輪廓誤差[9] 5
圖1-8放電介質高壓乾燥氣體(a)未補償(b)有補償[11] 6
圖1-8 放電工孔洞，實際深度與加工深度[19] 6
圖2-1放電加工機示意圖 13
圖2-2放電加工過程步驟圖[24] 14
圖2-3電極損耗後 (a)放電銑削之工件面(b)放電銑削移除與殘留體積之示意圖 18
圖2-4 電極補償構想 19
圖2-5一般放電銑削時(a)正常放電(b)稀疏放電發數(c)無放電狀態 20
圖2-6本文修整電極後之放電波形(a)正常放電(b)稀疏放電發數(c)無放電狀態 21
圖3-1 CNC放電加工機為億曜公司所生產之S430A 22
圖3-2超音波旋轉EDM主軸 23
圖3-3變頻器(台達VFD015B23A) 24
圖3-4 (a)電流探測棒 (b)差分探測棒 25
圖3-5.表面輪廓儀SJ-401 26
圖3-6. 表面粗度儀3-2-2 26
圖3-7 雷測顯微鏡(a)雷射共軛焦顯微鏡(b)量測面3D虛擬形貌 27
圖3-8 雙通道示波器(安捷倫型號DSOX 2012A) 28
圖3-9 超音波清洗槽 28
圖3-10上升補償機構示意圖 31
圖3-11 PLC控制板含控制按鈕(a)PLC FX2N32MT (b)三菱伺服器 32
圖3-12 上升平台動作示意圖 33
圖3-13 CNC EDM 實驗機構示意圖 34
圖3-14. 電極修整補償機構之CNC EDM機台 34
圖3-13實驗架構圖 35
圖4-1主軸無旋轉放電銑削(a)入口深度307.640μm(b)出口深度 230.702μm 37
圖4-2無旋轉放電銑削表面粗糙度 37
圖4-3 高速旋轉主軸 37
圖4-4電極修整方法(a)銑削電極 (b)車削電極 38
圖4-5. 電極端部(a)車削 (b)銑削 (c)放電加工後 39
圖4-6 電極端部Ra值(a)車削Ra=0.305μm (b)銑削 Ra=0.473μm 39
圖4-7量測電極旋轉偏擺 40
圖4-8 直徑3mm鉻銅棒各轉速下偏擺量 41
圖4-9車削電極端面(a)3000RPM (b) 3600RPM (c) 4200RPM，粗度值 42
圖4-10.直徑6鉻銅棒不同轉速(a)Ra (b)Rmax比較 43
圖4-11.修整後電極端部(a)200mm/min (b) 20mm/min 44
圖4-12 (A)6mm鉻銅棒修整前(B)Ra=0.373μm ,Rmax=0.536μm 45
圖4-14 (a)放電加工入口 (b)放電銑削前端Ra 46
圖4-15 放電銑削尾端Ra 47
圖4-16 一般放電銑削碳渣分佈 47
圖4-16 直徑3mm電極放電加工4mm深盲孔(a)放電深度(b)底部R角半徑 49
圖4-17直徑3mm電極未修整放電加工深盲孔底部粗糙度 49
圖4-18直徑3mm電極之程式補償放電加工盲孔(a)放電深度(b)底部R角半徑 50
圖4-19 直徑3mm電極之程式補償放電加工深盲孔底部粗糙度 50
圖4-20本文所提修整電極放電加工4mm盲孔(a)放電深度(n)底部R角半徑 51
圖4-21本文所提電極修整補償4mm深盲孔底部粗糙度 51
圖4-22 放電盲孔放電深度比較 52
圖4-23 直徑3mm電極放電加工盲孔(a)深度誤差 (b)底部圓角半徑(c)底部 53
圖4-24 直徑6mm未修整電極EDM盲孔(a)放電深度(b)底部R角半徑 55
圖4-25 直徑6mm未修整電極放電加工深盲孔底部粗糙度 55
圖4-26 直徑6mm電極程式補償EDM盲孔(a)放電深度(b)底部R角半徑 56
圖4-27 直徑6mm程式補償放電加工深盲孔底部粗糙度 56
圖4-28 直徑6mm經本文修整電極補償放電盲孔(A)放電深度(B)底部R角半徑 57
圖4-29 直徑6mm經本文修整電極補償放電加工深盲孔底部粗糙度 57
圖4-30 放電盲孔放電深度比較 58
圖4-31 直徑6mm電極放電加工盲孔(a)深度誤差 (b)底部圓角半徑(c)底部 59
圖5-1放電銑槽工件使用線切割剖面 61
圖5-2放電銑槽入口深度比較(a)未修整電極(b)電極修整放電銑槽 62
圖5-3 放電銑槽出口深度(a)未修整電極,(b)有修整電極 63
圖5-4 放電銑槽 (a)入口深度, (b)入口深度誤差, (c)出口深度, (d)出口深度誤差 64
圖5-5放電銑槽 (a)入口底部圓角半徑 (b)出口底部圓角半徑 65
圖5-6 放電加工後電極端部(a)旋轉放電加工盲孔(b)旋轉放電銑削 66
圖5-7銑削流程示意圖 (a)階梯尺寸(mm) (b)銑削階梯形貌 (c)斜曲面金字塔 67
圖5-8斜曲面金字塔結構 68
圖5-9顯微鏡觀察斜曲面金字塔結構 68
圖5-10放電銑削斜面示意圖 69
圖5-11 斜曲面金字塔3D輪廓 69
圖5-12 模仁設計圖片 70
圖5-13本文所提出 (a)未修整電極之放電銑削模仁之結構 71
圖5-14 放電銑削模仁後之電極 (a)經修整電極與(b)未修整電極 72
圖5-15 模仁斜面 (a)未修整電極 (b)經修整電極之放電銑削 73
圖5-16模仁斜面底部 (a)未修整電極 (b)修整電極補償法 74
圖5-17 未修整電極之放電銑削模仁輪廓 (a)橫截面位置 (b)橫截面高度 75
(c)黃區域量測值 75
圖5-18 修整電極放電銑削模仁(a)橫截面 (b)橫截面高度 (c)黃區域量測值 76
圖5-19 模仁斜面表面粗度測量(a)未補償 (b)經修整補償 77
圖5-20 放電銑削電極損耗過大，造成後面路淨空跑 78
圖5-21自動補償上升平台 78
圖5-22放電火花自動偵測輸入介面 79
圖5-23 (a) 式5-1 (b)式5-2 (c)式5-3之示意圖 80










表目錄
表3-1CNC放電加工機規格 22
表3-2放電主軸規格 23
表3.3 超音波變頻器規格 24
表-3-4不鏽鋼SUS430含量 29
表3-5 SUS430硬度量測 29
表4-1 放電參數+x方向 36
表4-2面粗度儀量測參數 39
表4-3 ECODE 9306放電加工參數 45
表4-4.放電加工參數 48
表5-1 放電銑槽參數 61
表5-2放電銑削面參數 67
表5-4 直徑6mm盲孔深度 80
表5-5 直徑3mm盲孔 81
表5-6 3mmX 10mmX 4mm銑槽 81

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