臺灣博碩士論文加值系統

放電加工機(EDM)是機械製造中非常重要的一環，從各種精密製造產業可知，放電加工機已被視為基本工具機之列。相較於其他先進國家，如瑞士與日本等國之產品，則我國放電加工機性能居次。主因乃放電加工製程緩慢(尤其主軸抬刀運動的時間，大幅減緩了加工效率)與加工面精度不足。為改善此一問題，放電加工之產學研各界皆積極投入研究主軸運動改善良方與機電控制技術領域，例如採用直接驅動式之高速抬刀主軸(Z軸)，期能大幅提昇本領域之核心技術。其中線性馬達具有高加速度與高精確度之特性，適合作為放電加工機主軸，特別在需要高速抬刀之場合，如：薄片深孔加工等。本研究發展以線性馬達直驅式之放電加工機主軸與極薄片之深孔加工控制策略為目標。主要研究項目包含：(一)建置雙邊平行線性馬達驅動之放電加工機主軸，(二)發展直接驅動之主軸運動控制系統，與配合之放電波型偵測電路，(三)主軸抬刀排渣運動之性能比較研究。其過程包含直驅式主軸之設計分析，線性馬達之模式與控制系統實現，與放電加工抬刀簡明自調式控制之設計與實現。從抬刀運動之基礎研究，探討加工速率分離現象(MSBP)，實驗發現傳統與直驅式EDM，均具有明顯之MSBP現象。在性能測試方面，則發現石墨薄片電極在深孔加工時，直驅式加工速率與面精度明顯高於傳統式；於銅棒與薄片電極方面，雖未見加工速度之改善，但加工精度與面粗度則明顯優於傳統式。應用放電波型電路計數放電脈波數與本文所提出之尋求最大加工效率之抬刀控制策略，則更可進一步提昇原伺服電壓控制方式之加工速率約達一倍，且薄板電極消耗小而均勻。綜合而言，直驅式主軸配合簡明自調式抬刀控制策略後，明顯地改善傳統式與直驅式伺服電壓控制方式在薄片深孔加工之加工速率、加工精度，與面粗度等各面向效益。究其原理，可能主要繫於高加速度抬刀運動之排渣效果。

In modern industry fields, EDM (Electrical Discharge Machining) is one of the most important options for precision mechanical manufacturing processes, and it is even considered as a sort of basic machine tools in these years. However, compared to other advanced product from Switzerland and Japan, EDM machines built by our country are still considered as lower ranking in both machining speed and precision. EDM is such a slow process that jump motion of electrode is the dominant factor for wasting the machining time. Therefore, both academic institutes and industries are interested in improving strategies eagerly. Recently, direct driven spindle with linear motors, providing high acceleration motion and high positioning accuracy, is emerged as a key-technology to meet the requirement. Especially, it is suitable to establish a novel spindle for very thin and deep plate’s EDM process.
This study developed a direct drive spindle with parallel linear motors and a simple control strategy for very thin plate's machining into deep hole. Integrated with an EDM control unit provided by ITRI Taiwan, it is aimed at both the fundamental research of the jump motion and the machining performance comparison with traditional rotary-motor machine. From deep hole experiments, both of direct drive EDM’s machining speed and surface integrity are obviously higher than that of traditional EDM with thin graphite plate. On the other hand, although it is slower than traditional one with copper rod and thin plate, it still provides much lower wear rate and better roughness. Moreover, associated with a simple control algorithm through counting the effective sparks, the direct drive’s machining speed can be even increased up to 100% with uniform and lower wear rate. It is evident that the proposed machining control strategy can improves both traditional and direct drive EDM (servo voltage) in machining speed, accuracy and surface integrity significantly. These results may be dominantly contributed by the high acceleration jumping of electrode, because it provides much efficient debris extrusion effect.

誌謝 I
摘要 II
ABSTRACT III
目錄 IV
圖錄 VIII
表錄 XIII
第一章 緒論 1
1.1 前言 1
1.2 文獻回顧 3
1.3 研究之背景與目的 9
1.3.1 本論文之背景、重要性 10
1.3.2 本論文之目的 10
1.4 本文結構 10
第二章 放電加工與線性馬達 12
2.1 放電加工 12
2.1.1 放電現象 12
2.1.2 放電形式轉換過程 14
2.2 放電電源系統 15
2.2.1 放電迴路分類 15
2.2.2 放電能量分類 18
2.2.3 EDM之電源系統 20
2.3 線性馬達 23
2.3.1 線性馬達之數學模式 25
2.4 EDM放電加工參數之意義與影響 29
第三章 直驅式放電加工主軸與極薄電極加工之控制策略 31
3.1 直驅式放電加工機設計 31
3.2 直驅式放電加工機之控制與機電整合 35
3.3 薄板深孔加工控制策略設計 35
3.4 放電波形量測電路與抬刀高度控制策略 36
3.4.1 放電波形分類 36
3.4.2 放電波形偵測電路 38
3.4.3 放電波形鑑別電路之實現與驗證 42
3.4.4 抬刀高度控制系統之實現 42
第四章 實驗設備與實驗規劃 48
4.1 實驗設備與實驗裝置 48
4.2 加工速度分離現象(MSBP)與加工速度之實驗 58
4.3 應用薄板電極之加工 58
4.4 自調式抬刀高度控制實驗 59
第五章 實驗結果與分析 60
5.1 直驅式放電加工機精度量測 60
5.2 排渣性能與加工速度分離現象(MSBP)實驗結果 62
5.2.1 傳統式EDM之MSBP與加工速度實驗數據分析 62
5.2.2 直驅式EDM之MSBP與加工速度實驗數據分析 65
5.2.3 傳統與直驅式EDM之MSBP與加工速度實驗數據比較 68
5.3 薄板加工與傳統伺服控制/自調式控制實驗比較結果 71
5.3.1 銅薄板電極加工之數據分析 71
5.3.2 石墨薄板電極加工之數據分析 73
5.3.3 直驅式EDM薄板加工簡明自調式控制實驗比較分析 75
5.4 加工表面精度之數據分析 78
5.5 加工後電極消耗情形 81
第六章 結論與建議 86
參考文獻 88
作者簡歷 91

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