lesson18Milling

1、Unit Seven Lesson18 Milling w教学目标及要求教学目标及要求 1.1.掌握课文有关铣床及铣削加工的专业词汇和专业术语；掌握课文有关铣床及铣削加工的专业词汇和专业术语； 2.2.结合铣床和铣削工艺的相关专业知识阅读课文，提高翻结合铣床和铣削工艺的相关专业知识阅读课文，提高翻译能力。译能力。 w重点重点 1.1.铣床及铣削工艺的专业词汇和专业术语；铣床及铣削工艺的专业词汇和专业术语； 2.2.翻译课文：铣床的类型及各类型的工作原理；翻译课文：铣床的类型及各类型的工作原理； 铣削的特点及使用场合；铣削的特点及使用场合； 铣削的工作原理。铣削的工作原理。u难句分析及翻译的基本

2、技巧难句分析及翻译的基本技巧 PartPart（） 几种具体问题的具体译法几种具体问题的具体译法 五、强调句型的译法五、强调句型的译法 w教学思路设计教学思路设计 时间分配（共时间分配（共100min100min）：）： 1 1、讲解课文中的专业词汇和术语、讲解课文中的专业词汇和术语; ; 2 2、讲解课后生词、大声朗读、讲解课后生词、大声朗读; ; 3 3、翻译课文，注意穿插相关专业知识；、翻译课文，注意穿插相关专业知识； 4 4、分析难点句型，讲解相关语法和翻译技巧；、分析难点句型，讲解相关语法和翻译技巧； 5 5、学生答疑。、学生答疑。ContentswBackground Knowle

3、dgewNew Words and PhrasedwText AnalysiswQuestionswLanguage Points & Translating Techniques wReading Materials wSummary wReferencesBackground Knowledgeu Milling is a basic machining process by which a Milling is a basic machining process by which a surface is generated by progressive chip removal

4、. surface is generated by progressive chip removal. u The workpiece is fed into a rotating cutting tool. The workpiece is fed into a rotating cutting tool. Sometimes the workpiece remains stationary, and the Sometimes the workpiece remains stationary, and the cutter is fed to the work. cutter is fed

5、 to the work. u In nearly all cases, a multiple-tooth cutter is In nearly all cases, a multiple-tooth cutter is used so that the material removal rate is high. used so that the material removal rate is high. u Often the desired surface is obtained in a single Often the desired surface is obtained in

6、 a single pass of the cutter or work, and because very good pass of the cutter or work, and because very good surface finish can be obtained, milling is surface finish can be obtained, milling is particularly well suited and widely used for mass-particularly well suited and widely used for mass-prod

7、uction work. production work. Background Knowledgeu Many types of milling machines are used, Many types of milling machines are used, ranging from relatively simple and versatile ranging from relatively simple and versatile machines that are used for general-purpose machines that are used for genera

8、l-purpose machining in job shops and tool-and-die work machining in job shops and tool-and-die work on highly specialized machines for mass on highly specialized machines for mass production. production. u Unquestionably, more flat surfaces are Unquestionably, more flat surfaces are produced by mill

9、ing than by any other produced by milling than by any other machining process. machining process. Milling MachineswTwo basic types of hnee-and-column milling machine (a) vertical; (b) horizontalMilling OperationsMilling cuttersNew Words and ExpressionsuTerms： 1. gang milling 1. gang milling 多刀铣削多刀铣削

10、 peripheral milling peripheral milling 圆周铣削圆周铣削 surface milling machinesurface milling machine平面铣床平面铣床 face milling face milling 平面铣平面铣 end milling end milling 立铣立铣( (端铣端铣) ) slot milling slot milling 铣槽铣槽 surface machining surface machining 曲面加工曲面加工 ball nose mill ball nose mill 球头铣刀球头铣刀 milling cu

11、tters milling cutters 铣刀铣刀New Words and Expressionsu Terms： 3.horizontal-spindle milling machine 3.horizontal-spindle milling machine 卧式铣床卧式铣床 vertical-spindle milling machine vertical-spindle milling machine 立式铣床立式铣床 4.allowance 4.allowance 切入长度切入长度 over travel over travel 切出长度切出长度 5.up milling 5.u

12、p milling 逆铣逆铣 conventional milling conventional milling 逆铣逆铣 climb milling climb milling 顺铣顺铣 down milling down milling 顺铣顺铣Text Milling operations can be classified into two broad categories called peripheral milling and face milling. Each has many variations. Text Peripheral or Slab Milling uIn p

13、eripheral milling the surface is generated by In peripheral milling the surface is generated by teeth located on the periphery of the cutter body. teeth located on the periphery of the cutter body. uThe surface is parallel with the axis of rotation The surface is parallel with the axis of rotation o

14、f the cutter. of the cutter. uBoth flat and formed surfaces can be produced by Both flat and formed surfaces can be produced by this method, the cross section on the resulting this method, the cross section on the resulting surface corresponding to the axial contour of the surface corresponding to t

15、he axial contour of the cutter. cutter. uThis process, often called slab milling, is usually This process, often called slab milling, is usually performed on horizontal-spindle milling machines. performed on horizontal-spindle milling machines. In slab milling, the tool rotatesIn slab milling, the t

16、ool rotates（millsmills）at some at some rpm value N while the work feeds past the tool at a rpm value N while the work feeds past the tool at a table feed rate ftable feed rate fm m in inches per minute. in inches per minute. Text Basics of peripheral or slab milling process Text Face And End Milling

17、 uIn face milling and end milling, the In face milling and end milling, the surface generated is at right angles to surface generated is at right angles to the cutter axis . the cutter axis . uMost of the cutting is done by the Most of the cutting is done by the peripheral portions of the teeth, wit

18、h the peripheral portions of the teeth, with the face portions providing some finishing face portions providing some finishing action. action. uFace milling is done on both horizontal Face milling is done on both horizontal and vertical-spindle machines.and vertical-spindle machines. Text Basic of f

19、ace and end milling process Text uFor either slab or face For either slab or face milling, surfaces can milling, surfaces can be generated by two be generated by two distinctly different distinctly different methods. methods. uU p m i l l i n g i s t h e U p m i l l i n g i s t h e traditional way t

20、o mill traditional way to mill a n d i s c a l l e d a n d i s c a l l e d conventional milling. conventional milling. The cutter rotates The cutter rotates against the direction against the direction of feed rate of the of feed rate of the workpiece.workpiece. Up or Conventional Milling And Climb o

21、r Down MillingText uIn climb or down In climb or down milling, the cutter milling, the cutter rotation is in the rotation is in the same direction as same direction as the feed rate. the feed rate. uThe method of chip The method of chip f o r m a t i o n i s f o r m a t i o n i s c o m p l e t e l y

22、 c o m p l e t e l y different in the different in the two cases.two cases. Up or Conventional Milling And Climb or Down MillingQuestionswWhat are the characteristics of milling comparing What are the characteristics of milling comparing with other metal cutting?with other metal cutting?wWhy is the

23、milling particularly well suited and Why is the milling particularly well suited and widely used for mass production?widely used for mass production?wWhat is the peripheral milling? And can use it on What is the peripheral milling? And can use it on vertical spindle machine?vertical spindle machine?

24、wWhat is face and end milling? Only a small part of What is face and end milling? Only a small part of the cutting is done by the peripheral portions of the cutting is done by the peripheral portions of the teeth in face milling. true or false?the teeth in face milling. true or false?wHow large of t

25、he lengths of over travel LHow large of the lengths of over travel LO O and the and the approach Lapproach LA A when face milling? when face milling?wWhat is the up or conventional milling? What is What is the up or conventional milling? What is climb or down milling? climb or down milling? Language

26、 Points & Translating Techniques wExample 1: Many types of milling machines are used, ranging Many types of milling machines are used, ranging from relatively simple and versatile machines that from relatively simple and versatile machines that are used for general-purpose machining in job shops

27、 are used for general-purpose machining in job shops and tool-and-die work on highly specialized machines and tool-and-die work on highly specialized machines for mass production.for mass production. 多种型号的铣床被广泛使用，范围包括在加工车间中用多种型号的铣床被广泛使用，范围包括在加工车间中用于大量生产的常规简易铣床和万能铣床，也包括在工模具车于大量生产的常规简易铣床和万能铣床，也包括在工模具车

28、间使用的高度专业化的各种铣床。间使用的高度专业化的各种铣床。 manymany引导的短句是主句；分词引导的短句是主句；分词rangingranging引导的短语作状引导的短语作状语，进一步说明铣床的种类和用途，该分词短语中又有由语，进一步说明铣床的种类和用途，该分词短语中又有由thatthat引出的定语从句，用来修饰引出的定语从句，用来修饰thatthat紧前面的紧前面的machinesmachines一词。一词。整个句子较长，翻译时只能意译。整个句子较长，翻译时只能意译。 wExample 2: Both flat and formed surfaces can be produced by

29、 Both flat and formed surfaces can be produced by this method, the cross section on the resulting this method, the cross section on the resulting surface corresponding to the axial contour of the surface corresponding to the axial contour of the cutter.cutter. 用这种方法可以进行平面铣削和成形铣削，铣削的横截用这种方法可以进行平面铣削和成

30、形铣削，铣削的横截面与铣刀的轴向轮廓一致。面与铣刀的轴向轮廓一致。 句中句中“,”,”后是一个分词独立结构，用作状语，表示结后是一个分词独立结构，用作状语，表示结果，其逻辑主语为果，其逻辑主语为the cross sectionthe cross section（横截面），分词为（横截面），分词为corresponding tocorresponding to（与（与一致）。一致）。 wExample 3: The cutting velocity is that which occurs at the The cutting velocity is that which occurs at

31、the cutting edges of the teeth in the milling cutter.cutting edges of the teeth in the milling cutter. 切削速度就是指铣刀齿切削刃上的速度。切削速度就是指铣刀齿切削刃上的速度。 that that 引导表语从句；引导表语从句；whichwhich在表语从句中作主语。用在表语从句中作主语。用此句型意在强调速度定义。此句型意在强调速度定义。wExample 4: The feed rate of the table, fThe feed rate of the table, fm m , in i

32、nches per , in inches per minute is related to the amount of metal each minute is related to the amount of metal each tooth removes during a revolution (this is called tooth removes during a revolution (this is called the feed per tooth), fthe feed per tooth), f1 1, , 工作台的进给量是与铣刀每一齿在铣刀每一转中切削工作台的进给量是

33、与铣刀每一齿在铣刀每一转中切削金属量有关的一个量，以金属量有关的一个量，以f fm m表示，其单位为英寸分钟，表示，其单位为英寸分钟，而每一齿的进给叫做齿进给，以而每一齿的进给叫做齿进给，以f f1 1表示，表示， wExample 5: 五、强调句型的译法五、强调句型的译法 在英语中，有一种强调句型在英语中，有一种强调句型“It is (was )that”It is (was )that”。它是用来强调除谓语之外的主语、宾语、状语部分的。这一它是用来强调除谓语之外的主语、宾语、状语部分的。这一强调句型是把需要强调的部分放在强调句型是把需要强调的部分放在“It is (was)”It is

34、(was)”的后面，的后面，而把句子的其余部分放在而把句子的其余部分放在that that 的后面，其特点是去掉的后面，其特点是去掉It is It is (was )that (was )that 后仍是一个完整的句子。翻译时常常在被强后仍是一个完整的句子。翻译时常常在被强调成分之前加上调成分之前加上“正是正是”、“就是就是”等词。具体译法有两种：等词。具体译法有两种： （一）保留原文结构（一）保留原文结构 It is It is heatheat that causes many chemical changes. that causes many chemical changes.（强调

35、（强调主语）主语）w 正是热引起许多化学变化。正是热引起许多化学变化。 It isIt is in industry in industry that metals have found their that metals have found their greatest use.greatest use.（强调状语）（强调状语）w 正是在工业上金属得到了最大限度的应用。正是在工业上金属得到了最大限度的应用。 （二）改变原文结构（二）改变原文结构 It is man that plays the leading role in the It is man that plays the leading role in the application of electronic computers.application of electronic computers.（强调主语）（强调主语）w 在应用电子计算机时，起作用的是人。在应用电子计算机