机械专业英语董建国第18章

1、Unit 18TEXT READING MATERIAL Unit 18Unit 18TEXTThe Function of Tooling The equipment，small or large, simple or complex，that adapts the production machine to the production of a specific part is known as tooling Machining requires two kinds of tooling：work-holding devices，such as a drill press vise；a

2、nd cutting tools，such as drills and reamers Unit 18 Work-holding devices are called jigs and fixturesThe two terms are often used interchangeably, but they have different meaningsA jig is a work-holding device that is not fastened to the machine；a fixture is fastened to the machineA familiar type of

3、 jig (or fixture) is the drill press vise that is used to hold work in position for light drilling operationsSuch a vise is a general-purpose or universal fixture and does not constitute a tooling charge against the jobUnit 18 Most of the machining we do in a machine shop is done with cutting tools.

4、 A cutting tool is a hardened piece of metal or other material，such as a grinding wheel，with a cutting edge that cuts the metal. Cutting tools are made in a wide variety of shapes and sizes. Each of them is designed for a specific purpose Unit 18LEARN TO SPEAKMr. Zhang:Hello, Mr. Chen.Mr. Chen: Hi,

5、Mr. Zhang.Mr. Zhang:I have some trouble with the cutting tools. Could you like to help me?Mr. Chen: Yes, I would like to do it. What are these problems?Mr. Zhang:How can we distinguish the kinds of cutting tools?Mr. Chen: We can distinguish them by their shape.Mr. Zhang:Oh.Unit 18Mr. Chen:This is a

6、cutting tool for turning and it have only one point and two edges.Mr. Zhang:Whatthis?Mr. Chen: It is a twist drill. It have two strip of spiral grooves and it usually is used for drilling a hole.Mr. Zhang:Whats that?Mr. Chen: That is end milling cutter. It is used for machining a plane.Mr. Zhang:Oh,

7、 I see. Thank you for telling me these.Mr. Chen: You are welcome.Unit 18NEW WORDS AND EXPRESSIONSfunction 5fQNkF(E)n n. 作用，数函数tooling tU:lIN n. 工夹具，工艺装备equipment I5kwIpmEnt n. 装备，设备，装置simple 5sImp(E)l adj. 简单的complex 5kRmpleks; (?) kEmp5leks adj. 复杂的n. 复合体specific spI5sIfIk adj. 特殊的Unit 18term t:m n

8、. 术语interchangeable IntE5tFeIndVEb(E)l adj. 可互换的interchangeably adv. 可互换地meaning 5mi:nIN n. 意义familiar fE5mIlIE(r) adj. 熟悉的charge tFB:dV n. 费用be known as 称作，叫做drill press 钻床familiar with 熟悉的tooling charge 工具(刀具)费用Unit 18NOTES 1The equipment，small or large, simple or complex，that adapts the productio

9、n machine to the production of a specific part is known as tooling 使机床适合加工某一特定零件的那种装备，不论其大小如何，简单复杂与否，均称为工夹具。 “small or large，simple or complex” 修饰前面的名词“equipment”。 这种成对使用的形容词，放在所修饰的名词后面，也含有修饰动词的意义。这里可译成：“不论其大小如何，简单复杂与否”。 Unit 18 2Such a vise is a general-purpose or universal fixture and does not con

10、stitute a tooling charge against the job 这样的虎钳也是一种通用的或者说是万能的夹具，并不对加工件构成工夹具费用。 “charge”在这里作“费用”解，“job”作“加工件”解。 3Most of the machining we do in a machine shop is done with cutting tools 我们在金工车间进行的大部分加工是用刀具来完成的。 “we do in a machine shop”是定语从句，修饰前面的“the machining”。 Unit 18 4A cutting tool is a hardened

11、piece of metal or other material，such as a grinding wheel，with a cutting edge that cuts the metal 刀具是一块具有切削刃的淬硬金属或其它材料，例如砂轮。 句中介词短语“with a cutting edge that cuts metal”中含有一个修饰“cutting edge”的从句，整个介词短语修饰“a hardened piece of metal or other material”。Unit 18EXERCISE 1Translate the following sentences in

12、to Chinese: (1) Bevel gears are those transmitting power or motion between two intersecting shafts (2) The worm and worm-gear are used on drives requiring large speed reduction at a right angle. (3) In general the production of a component will include several machining operations using a variety of

13、 machine tools (4) Being small in size and easy in operation，the electric driller can be carried from work to work.Unit 18 (5) using a lead screw in the cross slide，the toolholder can be moved across the carriage 2Translate the following sentences into Chinese by using dictionary. (1) Single-point t

14、ools are cutting tools having one cutting part and one shank (2) For the reasons，it is usual to machine the work-piece oversize deliberately during the roughing cut，leaving a small amount material that will subsequently be removed during the finishing cut. (3) The teeth on the worm slide against the

15、 teeth of the worm gear, producing a rolling action Unit 18 (4) The worm usually may be made with either right-hand or left-hand threads，depending upon the desired direction of rotation of the worm gear (5) Parts requiring hard surfaces are first machined to shape while the metal is in an annealed s

16、tate，leaving only a small amount of excess material for grinding (6) Very little pressure is required in this process，thus permitting its use on very thin work (7) Using simpler work-holding fixtures and fewer cutting tools，machine does the work which was formerly done on several machines. (8) A jig

17、 provides some means of guiding the cutting tool Unit 18READING MATERIALCutting Tools The metal cutting tool separates chips from the work-piece in order to cut the part to the desired shape and size. There is a great variety of metal cutting tools. Each of them is designed to perform a particular j

18、ob or a group of metal cutting operations in an efficient manner. For example, a twist drill is designed to drill a hole which has a particular size, while a turning tool may be used to turn a variety of cylindrical shapes. Unit 18 There are three basic types of metal cutting tools: single-point too

19、ls, Multiple-point tools, and abrasives. A single-point metal cutting tool has a single cutting edge and is used for turning, boring, shaping, and planing. The most common machine tool that employs the single-point cutting tool is the engine lathe. Multiple-point tools have two or more cutting edges such