臺灣博碩士論文加值系統

本論文之目的在探討線切割放電加工機之錐度加工研究，期望能以調變線張力來提高錐度加工之速度。以往錐度加工之研究，多以改善放電加工機機構為主，使上下導具同心相對，加工液能隨線之傾斜角度進入加工區，以解決加工液沖流不足問題，但對於傳統沖水式的線切割放電加工機，在不變動床台機構下，如何改善錐度加工速度則有必要研究。文中首先設計一系統獨立之放電波形鑑別器，用以分類加工中之放電波形，並將影響錐度加工的變數（沖水水壓、線張力與厚度變化）對放電波列中之短路波作一分析討論，從而得到錐度加工角度變化時，線張力之調變法則，繼而提升錐度加工速度。此外，並建立短路波對切割角度、線張力、床台進給率與放電休止時間的數學模式，在給定的參數下，輸入以上變數即可得到迴歸分析預估的短路波比例值，而不需透過波形鑑別系統量測，文中最後構想一錐度加工控制策略，以期能開發出線上控制之放電監控系統。

Improvement of the machining performance of the taper-cut machining process of the wire —EDM is studied, in a hope that higher machining speed can be obtained by way of adjusting the tension of the wire. Most of the studies to date regarding the taper-cut machining are aimed at modifying the mechanism of the wire—EDM machines, in an effort to have the upper and lower guides of the wire concentrically aligned so that the machining fluid, i.e. water, can be easily infused into the discharge area to overcome the insufficiency of the flushing of the fluid and therefore a higher machining speed can be applied. However, for the traditional wire-EDM machines of which the structure and mechanism are unlikely to be modified, it is necessary to investigate other possible approaches for reaching higher the machining speed. In this study, a stand-alone electronic system for discriminating the discharge pulses into two categories — short and normal sparks - is devised in the first place. The percentage of the short sparks against the total discharge pulses, also known as the “short ratio”, is introduced as an index of the machining performance. The lower short ratio implies the more favorable performance. Based on the analysis of pulse trains under various machining conditions involving different wire tensions, water flushing pressures, work piece thickness, the rule for adjusting the tension of the wire in order to have favorable machining speed, in accordance with different inclining angles of wire, is obtained. In addition, a regression equation in which the wire tension, the wire angle, the work feed rate and off time are set as the four variables while the short ratio as the dependent, is established. With the assistance of the equation, short ratio, can be estimated under any given values of the three variables, without the need of the discharge pulses discriminating system said above. In the end, this paper also proposes a control strategy for taper-cut machining process of wire-EDM so as to develop a real-time on-line discharge pulses monitoring system.

第一章 緒論........................................... 1
1-1 引言.............................................. 1
1-2 文獻回顧...........................................2
1-2.1錐度切割相關文獻............................... 2
1-2.2放電波形相關文獻............................... 4
1-3 研究目的.......................................... 6
1-4 本文結構.......................................... 7
第二章 放電加工原理................................... 8
2-1 放電加工原理............................... 8
2-2 放電火花結構及基本轉換過程................. 10
2-3 放電電源及波形............................. 13
2-4 線切割放電加工之特性....................... 18
第三章 實驗設備及放電波形辯識原理..................... 22
3-1 實驗設備與材料............................. 22
3-2放電波形辯識原理............................ 27
第四章 錐度加工之參數分析............................. 37
4-1 加工參數與短路波變化探討................... 37
4-1.1沖水水壓對短路波之影響.................. 38
4-1.2線張力對短路波之影響.................... 39
4-1.3厚度變化對短路波之影響.................. 40
4-2 錐度加工與短路波變化探討................... 42
4-2.1錐度切割角度與短路波之關係.............. 43
4-2.2錐度切割角度與線張力之關聯.............. 44
4-2.3迴歸分析................................ 50
4-3 錐度加工控制策略........................... 52
第五章 結論與展望..................................... 55
參考文獻.............................................. 57
附錄 A................................................ 60

[1]N. Kinoshita, M. Fukui, T. Fujii, “ Study on Wire-EDM：Accuracy in Taper-Cut, ’’ Annals of the CIRP, Vol.36/1, 1987.pp.119-122.
[2]H. O. Sagamihara, T. A. Hino, “ Apparatus for Guiding a Wire Electrode of a Wire Electrode Discharge Machine,’’ U.S.A. Patent No.4638140, Jan.20, 1987.
[3]L. Attilio, “ Method and Apparatus for Orienting the Wire Guidance Heads on Spark Erosion Cutting Equipment for Eroding with a Great Wire Slope, ’’ U.S.A. Patent No.4431896, Feb.14, 1984.
[4]陳顯彰, 線切式放電加工機錐度切割機構之構想, 碩士論文, 國立成功大學機械工程學研究所, 1994.
[5]H. Watanabe, T. Stato and I. Suzuki, “ WEDM Monitoring with a Statistical Pulse Classification Method, ’’ Annals of the CIRP, Vol. 39/1, 1990.pp.175-178.
[6]N. Kinoshita, M. Fukui, H. Shichida and G. Gamo, “Study on E.D.M. with Wire Electrode ; Gap Phenomena,’’ Annals of the CIRP, Vol.25/1, 1976.pp.141-145.
[7]吳正仲, 線切割放電加工之波列分析與應用, 博士論文, 國立台灣大學機械工程學研究所, 1996.
[8]K. P. Rajurkar, and W. M. Wang, “ A New Model Reference Adaptive Control of EDM,’’ Annals of the CIRP, Vol.38/1, 1989.pp.183-186.
[9]K. P. Rajurkar, and W. M. Wang, “ On-Line Monitor and Control for Wire Breakage in WEDM, ’’ Annals of the CIRP, Vol.40/1, 1991.pp.219-222.
[10]C. Co un, “ Computer Aided Evaluation and Control of Electric Discharge Machining by Using Properties of Voltage Pulse Trains, ’’ Int. J. Mach.Tools Manufact. Vol. 30/1, 1990.pp.237-247.
[11]G. Gamo, and M. Kinoshita, “ Taper Cutting Control Method and Control System in Wire-Cut Electric Discharge Machine, ’’ U.S.A. Patent No.4843203, Jun.27, 1989.
[12]M. Kinoshita, “ Wire EDM Taper Cutting Method Using Path Data of Two Planes of a Workpiece, ’’ U.S.A. Patent No.4703146, Oct.27, 1987.
[13]M. Weck and J. M. Dehmer,"Analysis and Adaptive Control of EDM Sinking Process Using the Ignition Delay Time and Fall Time as Parameter", Annals of the CIRP, Vol. 41/1, 1992.pp.243-246.
[14]蔡子琦, 類神經網路與基因遺傳演算法於WEDM加工參數最佳化之應用, 碩士論文, 國立台灣大學機械工程學研究所, 1999.
[15]高明義, 線切割式放電加工惡化與改善之研究, 碩士論文, 國立台灣大學機械工程學研究所, 1996.
[16]邱雲堯, 線切割放電加工（WEDM）斷線過程及偵測之研究,碩士論文,國立台灣大學機械學研究所,1992.
[17]陳建宙, 能量參數對線切割式放電加工的影響, 碩士論文, 國立台灣大學機械工程學研究所, 1998.
[18]C. C. Lee, “Fuzzy Logic in Control Systems: Fuzzy Logic Controller - Part I,” IEEE Trans. on System, Man, and Cybernetics, Vol. 20/2, 1990.pp.419-435.
[19]顏木田, 線切割放電加工之適應控制, 博士論文, 國立臺灣大學機械學研究所, 1995.
[20]許文政, 線切割放電加工轉角精度控制策略之研究, 博士論文, 國立臺灣大學機械學研究所, 1998.
[21]陳益原, 搖動電極放電加工參數最佳化之研究, 碩士論文, 國立臺灣大學機械學研究所, 1994.
[22]張渭川, 放電加工的結構與實用技術, 全華科技圖書公司, 民國79年11月
[23]中國生產力中心技術引進服務組, FUZZY 控制, 全華科技圖書公司