【正文】 看到了作為老師的偉大和崇高，在我以后的生活和工作中，所有的這一切都會讓我受益。在我四年學習期間，各個授課老師的言傳身教，認真教課，使我學到了扎實的公共基礎(chǔ)課程和專業(yè)知識。在此，我感謝老師們，向老師們說一聲：老師，你們辛苦了！同學們的幫助也是很重要的，在完成本次設計的過程中，與同學一起探討問題也使我學到了很多，是他們讓我感到學習不是一種負擔，而是一種快樂。在彼此的互相幫助中，這一切都讓我的學習、生活變得精彩。在這里，我向各位同窗好友表示衷心的感謝！還要感謝參考文獻中所列參考資料的作者。最后，還要感謝我的母校，是她讓我有了這樣的機會，讓我在此度過了人生中美好的四年。祝愿我的母校明天更美好。參考文獻[1].，.[2] （3）.機械工業(yè)出版社,2003[3].：機械工業(yè)出版社出版，2003.[4].[M].上海:上?？茖W技術(shù)文獻出版社,2000[5].王愛玲，白恩遠，,2001[6].：機械工業(yè)出版社出版，1993，5678[7].濮良貴，：高等教育出版社出版，2003，3231.[8].劉鴻文，高等教育出版社出版，2004，211231.[9].:化學工業(yè)出版社，2007，1294.[10].：北京理工大學出版社，2007，68111.[11]. ,2004[12].鄧星鐘，機電傳動控制．華中科技大學出版社,2002[13].張立勛,孟慶鑫,[M].哈爾濱:哈爾濱工程大學出版社,2000[14].：高等教育出版社出版，1995[15].：化學工業(yè)出版社出版，1994，355341.[16].，2007.[17].：電子工業(yè)出版社，2008，337342.[18].：機械工業(yè)出版社，2005，2392.附錄一 英語論文High Precision Finish Cutting by Dry WEDMAbstractThis paper describes the development of a new dry wire electrical discharge machining (dryWEDM) method, which is conducted in a gas atmosphere without using dielectric liquid to improve the accuracy of finish cutting. In dryWEDM, the vibration of the wire electrode is minute due to the negligibly small process reaction force. In addition, as the gap distance is narrower than that in conventional WEDM using dielectric liquid, and there is no corrosion of the workpiece, high accuracy in finish cutting can be realized in dryWEDM. However, some drawbacks of dryWEDM include lower material removal rate pared to conventional WEDM and streaks are more likely to be generated over the finished surface. Increasing the wire winding speed and decreasing the actual depth of cut are effective to resolve these drawbacks.Keywords: WEDM, dielectric, Finish cutting, Dry process1 INTRODUCTIONDryelectrical discharge machining (dryEDM) is a new EDM process, which is conducted in a gas atmosphere without using dielectric liquid. Diesinking EDM in dry condition was first attempted by Kunieda et al. [ I ] to discontinue the use of EDM working oil in consideration of environmental preservation, human health and prevention of fire hazards. They found other advantages of drydiesinking EDM such as。 1) significantly low tool wear ratio, 2) thinner white layer and lower residual stress, and 3) narrower discharge gap length.Kunieda et al. [2] found that when the EDM gap is filled with dielectric liquid, a considerably large process reaction force is applied to the tool electrode at the moment dielectric breakdown occurs. This is because a bubble is generated due to the evaporation and dissociation of the dielectric liquid, and because rapid expansion of the bubble is prevented by the influence of the inertia and viscosity of the dielectric liquid, resulting in extremely high pressure inside the bubble. In contrast, the process reaction force was found to be negligibly small when a discharge occurs in a gap filled with air instead of liquid.It is also known that an electrostatic force is applied between the tool electrode and workpiece [3][4] mainly during the discharge delay time in which an open voltage is applied between them. When the discharge energy is small, the influence of the electrostatic force cannot be ignored in parison with the abovementioned reaction force due to the expansion of the bubble. Obara et al. [4] pointed out that, since the electric permittivity of water is eightytwo times higher than that of air, the electrostatic force in conventional wire EDM (WEDM) using deionized water as the dielectric liquid is greater than when air is used as the dielectric fluid.Since WEDM uses as tool electrode a thin and flexible wire, the wire electrode is subject to deformation and vibration due to the abovementioned forces, resulting in unfavorable geometrical error of the machined surface. This fact motivated Furudate et al. [5] to investigate the fundamental characteristics of finish cutting conducted in air. They found that dryWEDM produces excellent straightness of the finished surface but material removal rate is lower than conventional WEDM. The present study aims to clarify the characteristics of dryWEDM in further detail and propose methods to improve dryWEDM.2 PRINCIPLEThe new dryWEDM method developed in the present work basically eliminates the use of dielectric liquid. Hence both the reaction force and electrostatic force are negligibly small pared to those in conventional WEDM using deionized water, resulting in considerably better accuracy in finish cutting. Furthermore, dryWEDM is free from the serious problem of electrolytic corrosion caused by electrolytic current flowing through water encountered in conventional WEDM.Tanimura et al. [6] proposed a new EDM process using water mist, which requires no tank for the working liquid and hence can easily be bined with other machining processes. They also pointed out that mistEDMMIEDM enables nonelectrolytic machining even when electrically conductive water is used as the working liquid. They were however not able to find other characteristics that are superior to those in conventional EDM, although dryEDM has many advantages such as, extremely low tool wear ratio, higher precision, narrower gap, smaller process reaction force, and smaller heat affected zone.3 EXPERIMENTAL METHODGround flat surface of carbon steel or tool steel was finishcut by conventional and dryWEDM, and material removal rate, straightness, surface roughness, waviness and gap length were pared. With conventional WEDM, water, whose electric conductivity was adjusted moderately, was jetted from the upper and lower nozzles. With dryWEDM, no water was supplied and cutting was performed in atmosphere. To obtain material removal rate, the removed volume was divided by the machining time. The removed volume can be obtained by integrating the product between the actual depth of cut and the fed distance of the wire electrode with the distance along the wire from the bottom to the top surface of t