数控专业英语3-5.doc

课程教案授课时间第14周第1、2节课2009年5月18 H课次14授课方式 （请打V）理论课（V） 讨论课（） 实践课（） 习题课（）其他（）课时 安排授课题目（教学章、节或主题）：3.4.1 NC Electric Discharge Shaped Machine3.4.2 NC WEDM Machine教学目的、要求（分掌握、熟悉、了解三个层次）：目的：掌握特种加工中的电火花加工与线切割的工作原理及英文表达 要求：理解电火花加工与线切割的机床组成及英文表达教学内容重点及难点：重点：电火花加工与线切割的工作原理 难点：电火花加工与线切割的工作原理教具作业 思考题课后小结教学基本内容方法及手段-: New words and phrases♦ discharge 匕放电♦ spark n.火花♦ erode v.腐蚀，磨损♦ erosion 门•腐蚀，磨损♦ roughness n.粗糙度♦ electrode n.电极♦ density 九密度♦ gasify 匕汽化♦ minute 日力：微小的理论讲授方法及手段教学基本内容■corrode匕蚀，蚀除■melt匕熔化■seatter散布replicateV.复制reciprocate匕往复，互换rigidityn.刚性pulleyn.滑轮，滑车gangn. 一组，一群insulationn.绝缘flushV.清洗、contentElec trical discharge machining (EDM), or spark machining, as it is so called, is based on the eroding effect of an elec trie spark on both the electrodes used to produce・ The advantage is that electrical discharge machining processes with good surface roughness and machines metal of any hardness・放电加工或称为电火花加工，是基于两电极之间产生的电火花的腐蚀 作用实现的。

电火花加工的主要优点是可获得较低的表面粗糙度，并 且可以加工任何硬度的金属♦ Impulse power is linked to the tool electrode and the workpiece・ Using automatic feed adjustment device makes the tool electrode and the workpiece all along keep a small discharge gap・ By the action of impulse electrie current, spark discharging is produced. The constant impulse discharge will replicate the tool shape of the tool electrode on the workpiece and carry out the shaped machining.在工具电极与工件之间连接脉冲电源，利用自动进给调节装置使工具 电极与工件始终保持一个很小的放电间隙在脉冲电流的作用下，产 生火花放电不断的脉冲放电，就可将工具电极的形状复制在工件上， 实现成型加工。

♦ NC electrie discharge shaped machining machine is composed of machine itself, impulse power, automatic feed adjustment device, NC system, working liquid cycle system and so on.数控电火花成型加工机床由机床本体、脉冲电源、自动进给调节装置、 数控系统、工作液循环系统等组成教学基本内容方法及手段♦ The basic principal of WEDM is that the continuously moving thin metal wire is taken as tool electrode and the pulsating current is linked to the metal wire and the workpiece, and t hen with the impulse spark discharging bet ween the metal wire and the workpiece, the metal is made to be melted or to be gasified. During the relative movement of the electrode wire and workpiece, the workpiece is cut and shaped. WEDM is also called wire cut.电火花线切割的基本原理是利用连续移动的细金属丝作为工作电极， 并在金属丝与工件之间通以脉冲电流，利用它们之间的脉冲火花放电 效应，使金属熔化或汽化，并通过电极丝与工件的相对运动，对工件 进行切割成型。

电火花切割也简称为线切割♦ (1) WEDM\ HS . The electrode wire of this kind of machine tool carries out high-speed and reciprocating movement. So it is also called reciprocating or rapid wire cutting machine・、 高速走丝线切割机床，这类机床的电极丝做高速往复运动，也称为 往复走丝或快走丝线切割机♦ (2) WEDM-LS . The electrode wire of this kind of machine tool carries out low—speed and single movement. So it is also called single or slow wire cutting machine・低速走丝线切割机床，这类机床的电极丝做低速单向运动，故也称为 单向走丝或慢走丝切割机参考资料：备注：注：课程教案按授课次数填写，每次授课均应填写一份；重复班授课可不另填写教案。