江西制造职业技术学院 江西制造职业技术学院 English for Mechanical Engineering Reading Comprehension 机械专业英语阅读

Unit Two: Manufacturing Engineering

Passage Two Fundamentals of Turning and Boring on Lathe

Learning Objectives To understand the whole passage. To know how to speak the basic components of the lathe in English. ★ ★ ★ To understand the functions of lathe-type machine tools.

Training Target In the part, our target is to train your reading speed. You should pay more attention to “word group”. Treating a group of words as a whole unit is a short cut to save your time.

Teaching Procedures Step D: Assignment Step C: Structural Analyzing Step B: Passage Understanding Step A: Lead in

Lead- in ： reviewing Do you remember what is the definition of turning in unit one?

Turning is a type of metal processing operation where a cutting tool is used to remove an unwanted material to produce a desired product, and is generally performed on lathe. Lead- in ： reviewing

Answer the following questions after fast reading. 4. What are the different kinds of turning ? Passage Understanding 1. What is a lathe? 2.How many kinds of lathe-type machine tools in industry? 3.What are the most basic components of the lathe?

Introduction of lathe: A lathe is a machine tool used primarily for producing surfaces of revolution and flat surfaces. It is one of the oldest and most versatile machining tools in modern production.

Passage Understanding Introduction of lathe: This machine is particularly adapted to cylindrical processing, it may also be used for other purposes, such as facing, groove cutting, boring and internal turning, taper turning, thread cutting and knurling and so on. 这种机床特别适用于圆柱表面的加工，也可用于其他加工， 如端面加工，槽加工，车镗内圆面，锥面加工，螺纹加工 和滚花纹。

How many kinds of lathe-type machine tools in industry? 2. Turret lathe 六角车床 Passage Understanding 1.Engine lathe 普通车床 3. Vertical turning and boring mill 立式车床 4.Aotomatic lathe 自动化车床 5.Special lathe 专用车床

What are the most basic components of the lathe? Passage understanding 1.Lathe bed Bed is the main frame of engine lathe. It is made of cast iron to damp vibration. 2. Headstock The headstock is a subassembly that is mounted on the left end of the bed.

What are the most basic components of the lathe? Passage understanding 3. Tailstock The tailstock is mounted on the inner ways at the right end of the lathe bed. 4. Carriage The lathe’s carriage is a subassembly that is mounted on the outer ways of the machine between the headstock and the tailstock.

What are the most basic components of the lathe? Passage understanding 5. Saddle The saddle is an H- shape casting that forms a bridge across the top of the bed.

What are the different kinds of turning ? Passage understanding 1.Cylindrical turning cylindrical turning is simplest and the most common of all lathe operations. Workpiece that is machined is usually held with a lathe chuck which is mounted on the headstock spindle nose and a center mounted on the tailstock if the workpiece is long.

What are the different kinds of turning ? Passage understanding 2. Facing The result of a facing operation is a flat surface that is either the whole end surface of the workpiece or an annular intermediate surface like shoulder.

What are the different kinds of turning ? Passage understanding 3. Groove cutting In cut- off and groove – cutting operations, only cross feed of the tool is employed. 4. Boring and internal turning Boring and internal turning are performed on the internal surfaces by a boring bar or suitable internal tools.

What are the different kinds of turning ? Passage understanding 5.Taper turning Taper turning is achieved by driving the tool in direction that is not parallel to the lathe axis but inclined to it with an angle that is equal to the desired angle of the taper.

What are the different kinds of turning ? Passage understanding 6.Thread cutting When performing thread cutting strict motion relationship must be kept between the spindle and the tool. The axial feed is kept constant by means of lead screw.

What are the different kinds of turning ? Passage understanding 7. Knurling knurling is mainly a forming operation in which no chips are produced. 8. Lathe cutting tools Usually the type of lathe tools which is used for processing depends on the purpose for which they are employed. The most common used are turning tools, facing tools, thread- cutting tools and forming tools.

Sentences Structure On a geared- head lathe, the headstock supports and encloses a train of gears that rotate the headstock spindle at rpm which are suited to the operating conditions of different jobs routed to the machine. 主语： the headstock 谓语： supports and encloses 宾语： a train of gears 状语： on a geared- head lathe 关系词： that ， which 从句 : rotate the headstock spindle at rpm, are suited to the operating conditions… 在齿轮驱动的机床上，主轴箱包括一个轮系，使主轴以每分钟多 少转的转速旋转，适合于机床上不同工件加工工艺路线的要求。

Sentences Structure It supports and rotates workpieces about the axis of the lathe, that is, about the horizontal line which is fixed by the center line of the headstock spindle. 主语： it 谓语： supports and rotates 宾语： workpieces about the axis of the lathe 关系词： that is, which 同位语： about the horizontal line 从句： is fixed by the center line of the headstock spindle. 它可以支持工作，使工件饶机床主轴回转，也就是绕主轴箱主 轴的中心线回转。

Sentences Structure The third part, the quill is a hardened steel tube, which can be moved longitudinally in and out of the intermediate part as required. 主语： the third part, the quill 谓语： is 宾语： a hardened steel tube 关系词： which 定语从句： can be moved longitudinally in an out of the intermediate part as required. 第三部分套筒是一个淬硬钢管，根据需要沿中间不见伸出或缩回。

Sentences Structure Its function is to hold and move the turning and boring tools that are used on the machine. 主语： its function 系动词： is 表语： to hold an move the turning and boring tools 关系词： that 定语从句： are used on the machine 功能是装夹用于切削的车刀和镗刀。

Structural Analyzing Part One: Para 1-2: Introduction of lathe; Part Two: Para 3-8: Basic components of an engine lathe ； Part Three: Para 9-16: Lathe work.

exercises Translate the following words into English. 套筒 纵向供给 尾架 quill 复合刀架 rotary motion 横向滑板 cross side longitudinal feeds 手动控制杆 hand lever 车削锥面 turning taper tailstock 丝杠 lead screw 床鞍 carriage 花盘 faceplate

Assignment Answer the following questions according to the text. 1. Describe the functions of the headstock and the tailstock. 2. On the lathe, how to control the motion of the turning tools? Please answer in different turning operations.

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