Unit 3 Lesson 7

1、Professional English for Mechanical Engineering Lecturer: Xiaobin CuiPart II Interchangeability and MeasurementLesson 7 Working DrawingLesson 7Working Drawing Working drawing are the drawings from which a design is implemented. All principles of orthographic projection and techniques of graphics can

2、 be used to communicate the details of a project in working drawings. A detail drawing is a working drawing of a single part (or detail) within the set of working drawings.Definitionsworking drawing工作圖,施工圖orthographic , :rfik adj.正投影的 orthographic projection 正投影detail drawing 詳圖 零件圖在工作圖中，所有正交投影法則法則和

3、圖形技技術(shù)術(shù)均可用可用來表達(dá)設(shè)計方案的細(xì)節(jié)。Lesson 7Working Drawing Specifications are the written instructions that accompany working drawings. When the design can be represented on a few sheets, the specifications are usually written on the drawings to consolidate the information into a single format.Definitionsspecifi

4、cations ,spsfken n. 技術(shù)要求當(dāng)設(shè)計內(nèi)容在多張圖紙上表達(dá)時，通常在工作圖上注明技術(shù)要求注明技術(shù)要求，從而確保圖紙信息的統(tǒng)一性。consolidate knslideit vt.鞏固，統(tǒng)一，整理All parts must interact with parts to some degree to yield the desired function from a design. Before detail drawings of individual parts are made, the designer must thoroughly analyze the workin

5、g drawing to ensure that the parts fit properly with mating parts, that the correct tolerances are applied, that the contact surfaces are properly finished, and that the proper motion is possible between the parts. Lesson 7Working DrawingYield 產(chǎn)生，形成mating parts 配合件tolerance tlrns n.公差；規(guī)定公差 在繪制單個零部件的

6、詳圖之前，設(shè)計人員設(shè)計人員必須對工工作圖作圖進(jìn)行充分分析分析，以確保零部件之間的配合良好、采用正確的公差、可對接觸面進(jìn)行合理的加工，以及零部件之間能夠產(chǎn)生合理的運(yùn)動。RequirementsMuch of the work in preparing working drawings is done by the drafter, but the designer, who is usually an engineer, is responsible for their correctness. It is working drawings that bring products and sys

7、tems into being. Working drawings are legal contracts that document the design details and specifications as directed by the engineer. Therefore drawings must be as clear, precise, and thorough as possible. Lesson 7Working Drawingbringinto being 使出現(xiàn)，實(shí)現(xiàn)，產(chǎn)生，建立工作圖的許多準(zhǔn)備工作工作是由繪圖員來完成完成的，而圖紙的正確性則要由設(shè)計者負(fù)責(zé)，設(shè)計

8、者通常是工程師。RequirementsRevisions and modifications of a project at the time of production or construction are much more expensive than when done in the preliminary design stages. Poorly executed working drawings result in wasted time and resources and increase implementation costs. To be economically c

9、ompetitive drawings must be as error-free as possible.Lesson 7Working Drawing生產(chǎn)或施工中修訂修訂和更改更改設(shè)計方案所需成本成本要比初步設(shè)計階段高高很多。RequirementsThe inch is the basic unit of the English system, and virtually all shop drawings in the U.S. are dimensioned in inches. The millimeter is the basic unit of the metric syste

10、m. Metric abbreviation (mm) after the numerals is omitted from dimensions because the SI symbol near the title block indicates that all units are metric.Lesson 7Working Drawingabbreviation ,bri:viein n. 縮寫，縮寫詞title block 標(biāo)題欄由于在標(biāo)題欄附近的國際單位制（SI）符號標(biāo)明所有單位為公制，因此尺寸數(shù)字后面的單位縮寫單位縮寫（mm）要省略省略標(biāo)注。RequirementsSome

11、working drawings carry both inch and millimeter dimensions, usually the dimensions in parentheses or brackets are millimeters. The units may also appear as millimeters first and then be converted and shown in brackets as inches. Converting from one unit to the other results to fractional round-off e

12、rrors. And explanation of the primary unit system for each drawing should be noted in the title block.Lesson 7Working Drawingparenthesis prenisis n. 圓括號bracket brkit n.方括號有些圖紙圖紙的尺寸單位既有英寸有英寸也有毫米毫米，通常在圓括號或方括號中的尺寸以毫米為單位.fractional frknl adj.分?jǐn)?shù)的，小數(shù)的round-off 四舍五入，抹去零頭RequirementsTitle Blocks In practice

13、，title blocks usually contain the title or part name, drafter, date, scale, company, and sheet number. Other information, such as tolerances, checkers, and materials, also may be given. Any modifications or changes added after the first version to improve the design is shown in the revision blocks.

14、Depending on the complexity of the project, a set of working drawings may contain from one to more than a hundred sheets. Therefore, giving the number of each sheet and the total number of sheets in the set on each sheet is important (for example, sheet 2 of 6, sheet 3 of 6, and so on).Lesson 7Worki

15、ng DrawingTitle Blocks Parts List The part numbers and part names in the parts list correspond to those given to each part depicted on the working drawings. In addition, the number of identical parts required is given along with the material used to make each part. If all working drawings in a set a

16、re the same scale, you need to indicate it only once in title block on each sheet. If several detail drawings on a working drawing are different scales, indicate them on the drawing under each set of views. In this case, indicate, “as shown” in the titleLesson 7Working Drawingpart list 零件明細(xì)表，材料清單as

17、shown 如圖所示Part Listblock opposite scale. When a drawing is not according to the scale, place the abbreviation NTS (not to scale) in the title block.Part Names and Numbers Give each part a name and number, using letters and numbers 1/8-in. (3 mm) high. Place part numbers inside circles, called balloo

18、ns, having diameters approximately four times the height of the number. Place part numbers near the views to which they apply, so their association will be clear. Lesson 7Working Drawingnot to scale 不按比例part number 零部件序號將部件序號置部件序號置于直徑約四倍數(shù)字高度的圓內(nèi)，稱為帶圓圈的數(shù)字。Part ListPart Names and NumbersOn assembly dra

19、wings, balloons are especially important because the same parts numbers are used in the parts list. People who check drawings must have special qualifications that enable them to identify errors and to suggest revisions and modifications that result in a better product at a lower cost. Lesson 7Worki

20、ng Drawing 圖紙審核員審核員必須具有有專業(yè)任職資格資格，才能識別錯誤，并能提出修訂和修改方案，從而以相對較低的成本生產(chǎn)出較高質(zhì)量的產(chǎn)品。Part Names and NumbersCheck and RevisionA checker may be chief drafter experienced in drafting and manufacturing processes or the engineer or designer who originated the project. In large companies, personnel in the various sho

21、ps involved in production review the drawings to ensure that the most efficient production methods are specified for each part.Lesson 7Working Drawing在大型公司，與生產(chǎn)相關(guān)的各部門要有專人人對圖紙圖紙進(jìn)行復(fù)審復(fù)審，以確保每個零部件均已指定最有效生產(chǎn)方法。Check and RevisionCheckers never check the original drawing; instead, they mark corrections with a colored pencil on a blue-line print. They return the marked-up print to the drafter who revises the original and makes another print for final approval. Checkers inspect a working or detail drawing for correctness and soundness of design. In addition, they are responsible for th