臺灣博碩士論文加值系統

放電加工於模具產業中扮演著極其重要的角色，除了容易加工高硬度材料，另一個理由則是可以加工模具中不易切削的微細與內尖角特徵；然而放電加工的前置作業卻十分耗時，雖然部分商用CAD/CAM軟體被廣泛用於放電加工前置作業，但其功能還不完善需大量仰賴操作者經驗與判斷。本研究將發展一套可以辨識CAD圖檔於三軸銑削中因刀具形狀與尺寸限制而形成的未切削區域(Uncut Region)軟體，代替以往使用人力識別與量測的方式，並將辨識後結果組合成放電區域自動生成電極圖檔，取代手動生成電極圖檔等十分耗時的前置作業。
未切削區域的辨識方法是以主曲率(Principal Curvature)來計算刀具與曲面之間的干涉情形，如果發生干涉即會產生未切削區域，這些區域會經由演算組合而成放電區域。於放電區域中，藉由本研究提出的開放邊提示法(Open Edge Hints)，以開放邊做為修剪提示，依序對實體方塊修剪最終可得該特徵之初步電極，並且符合電極設計時需考量的電極延伸要素。獲得初步電極後，本研究考量電極的大小、位置、加工性、電極進給方向與電極加工母材尺寸等因素，盡可能將電極合併一起或是置於同一電極基座上，並且自動生成該電極基座。
模具驗證結果顯示，以本研究提出的特徵辨識演算法，成功辨識出射出模具裡的未切削區域，這些區域被組合成62個放電區域，並成功生成62個電極，生成失敗為0個，62個電極皆符合電極設計概念，其中有14個電極，如果再經手動修改，可以使電極更容易加工。最後這些電極經由電極組合後從62個電極減少成42個電極，整體運算時間僅9分32秒。

The EDM process is particularly important in the machining of mold. In addition to processing high-hardness steel easily, it can process sharp corners that cannot be processed by tools or thin regions which are unsuitable for milling. However, the pre-procedure of EDM is time-consuming. Although some commercial CAD/CAM software is widely used in EDM pre-processing, its functions are not yet perfect and require a lot of experience and judgment from operators. This research will develop a set of software that can recognize the uncut regions which cannot be machined in 3-axis CNC because of tool shape and tool diameter to replace the method of using human identification and measurement, and generate electrode CAD files on EDM regions formed by uncut regions to replace time-consuming pre-process such as manually generating electrode CAD files.
The method of recognizing uncut regions is to calculate the interference between the tool and the surface by the principal curvature. If interference occurs, uncut regions will be generated, and these regions will be assembled by calculation to form EDM regions. In EDM regions, by using the Open Edge Hints which is proposed in this research, open edges as a trimming hint are used to trim solid squares to obtain preliminary electrodes, and they meet the extension conditions that need to be considered during electrode design. Finally, this research considers the electrode size, position, processability, material size, feed direction, and other factors to combine the electrodes or put them on the same electrode base as much as possible, and automatically generates the electrode base.
The results show that the recognition algorithm proposed in this research successfully recognizes the uncut regions in the injection mold. These regions are assembled into 62 EDM regions, and 62 electrodes are successfully generated, 14 of which will be machined more easily if they are modified by manual operation. Lastly, after combining the electrodes, these electrodes are reduced from 62 electrodes to 42 electrodes, and the overall calculation time is only 9 minutes and 32 seconds.

口試委員會審定書 i
致謝 ii
摘要 iii
ABSTRACT iv
目錄 vi
圖目錄 ix
表目錄 xvi
第1章 緒論 1
1.1 前言 1
1.2 文獻回顧 2
1.2.1 特徵辨識應用回顧 2
1.2.2 未切削區域辨識文獻回顧 3
1.3 研究目的 8
1.4 論文架構 9
第2章 相關技術理論 10
2.1 CAD建模 10
2.1.1 特徵辨識技術 10
2.1.2 形體表示模型 17
2.1.3 CAD圖檔格式 27
2.2 放電加工應用於模具製造 28
2.2.1 放電加工種類 28
2.2.2 雕模放電電極 29
2.2.3 放電加工原理 31
第3章 未切削區域特徵辨識演算法 33
3.1 定義與方法設計 33
3.1.1 未切削區域定義 33
3.1.2 未切削區域辨識方法 34
3.2 未切削區域辨識 36
3.2.1 CAD前處理 36
3.2.2 自干涉計算 36
3.2.2.1 曲面分類 40
3.2.2.2 曲面凹凸辨識 43
3.2.2.3 自干涉計算流程 45
3.2.2.4 自干涉計算結果 50
3.2.3 交互干涉計算 58
3.2.3.1 表面篩選 58
3.2.3.2 交互干涉計算流程 59
3.2.3.3 交互干涉計算結果 62
第4章 自動電極生成 66
4.1 方法流程 66
4.2 區域組合 67
4.2.1 H-Edge分解法概念 67
4.2.2 兩表面之間凹凸判別方法 68
4.2.3 區域組合流程 70
4.3 初步電極生成與設計 71
4.3.1 電極設計概念 71
4.3.2 電極生成原理 72
4.3.3 開放面延伸 73
4.3.4 初步電極生成流程 77
4.3.5 初步電極生成結果 81
4.4 電極進給方向 83
4.4.1 電極進給方向計算流程 83
4.4.2 進給方向計算結果 87
4.5 電極組合 89
4.5.1 電極組合流程 89
4.5.2 電極組合結果 91
4.6 總型加工電極 93
第5章 程式實作驗證 95
5.1 開發套件與環境 95
5.2 驗證案例:射出模具 95
5.2.1 未切削區域辨識結果 96
5.2.2 電極自動生成結果 99
5.3 其他驗證案例 107
第6章 結論與未來展望 114
6.1 結論 114
6.2 未來展望 115
參考文獻 116

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