国外机械工程图识读手册-粗糙度
识读零件图中表面粗糙度、尺寸公差
偏差小写为轴），查附录可得上下极限偏差为
。 0.025
0.050
3.尺寸公差标注
标注在圆柱特征延长线上
（4）表面粗糙度的简化标注：
大多数表面有相同结构要求的简化注法 多个表面有共同要求的注法
只用表面结构符号的简化注法
（5）表面粗糙度标注示例：
二、极限偏差与尺寸公差 1.基本概念
基本偏差系列图示
（4）尺寸公差标注含义：
Φ50f7的含义：基本尺寸为Φ50，基本偏差为f的7级轴（基本
项目五 机械图样的识读
任务2、3、4 识读零件图中的表面粗 糙度、尺寸公差 、形位公差
一、表面粗糙度的含义及标注
（1）含义：指加工时零件表面具有的较小间距和峰 谷组成的微观几何不平度。 （2）符号及含义：
（3）表面粗糙度在图样上的标注：
公差框格上
2019-机械图纸说明(上)-文档资料
2
標准
CNS(台灣標准) ISO(國際標准化) GB(中國大陸國家標准) GJB(中國軍方標准) JIS(日本工業標准) ANSI(美國國家標准) MIL(美國軍方標准） BS(英國國家標准) NF(法國國家標准) DIN(德國國家標准) CEN(歐洲標准） ASTM(美國材料與實驗協會標准） VDE(德國電器工程師協會標准)
工程機械制圖說明
統用工程制圖說明
目錄
上篇﹕基礎理論知識 •介紹 •使用量測工具的基本手法 •圖紙常見的國際標號 •圖紙中常見的英文含義 •常見的化學成分 •基本定意和知識
1
介紹
•在工程制圖量測說明是說明或溝通最初設計意圖和 產品功能的. •它使用的是在電子行業里國際公認的繪圖符號(ISO) 和國標標准（GB),它們在技朮內容上是同等的（idt) 或修改采用的(mod) •在使用這些同類的繪圖時,我們必須接受以下几點:
JOINT:接合處,鉚合處 SHELL:外面,外殼
MATERIAL:物料. NOTE:備注 BURR:毛邊 THICKNESS:厚度 ANGLE:角,角度 SURFACE:表面 OIL:油污. OXIDATION:氧化. SCRATCH:劃傷
FINISH:結束,磨光 BRACKET:支架,托架 SIGN:符號 PRODUCTION:生產 JOINT:接合處,鉚合處
4
圖紙上常見英文含義:
Sectional views剖視圖 Pictorial drawings立體圖 SCALE:比率 Mechanical drawings機械制圖
Lines圖線 Reference參考的
1 国外机械图纸常用的单词与缩写
国外机械图纸常用的单词与缩写1组织与标准国际标准化组织（旧称ISA）：ISO美国国家标准（旧称ASA）：ANSI英国标准：BS日本工业标准：JIS法国标准：NF德国标准：DIN澳大利亚标准：AS加拿大标准：CSA2常见图纸的标注及要求英文工程图纸的右下边是标题栏（相当于我们的标题栏和部分技术要求），其中有图纸名称（TILE）、设计者（DRAWN）、审查者（CHECKED）、材料（MATERIAL）、日期（DATE）、比例（SCALE）、热处理（HEATTREATMENT）和其它一些要求，如：1)TOLERANCESUNLESSOTHERWISESPECIFIAL未注公差。
2)DIMSINmmUNLESSSTATED如不做特殊要求以毫米为单位。
3)3)ANGULARTOLERANCE±1°角度公差±1°。
4)4)DIMSTOLERANCE±0.1未注尺寸公差±0.1。
5)5)SURFACEFINISH3.2UNLESSSTATED未注粗糙度3.2。
SCALE表示绘图比例。
ITEMNo.设备号或货号NOOFF件数STYLENo.型号DRG.No.图纸序号全称DrawingNumberSHEET:页码号或理解为第几页REVISIONNo:修订号DESIGNED&DRAWN:设计与制图签名处也有表示为DRAWNBY,简写为DWNDATE:日期MAT'L:材料也有简写为MATDESCRIPTION说明(或备注、名称)DIRECTORY\FILENAME:电子文档存放目录\文件名APPROVED批准签字简写为APPDCHECKED审核签字简写为CKDTRACED描图签字简写为TCDHeatTr热处理Donotscaledrawing不按比例绘制View:视图localviews:局部视图inclinedviews:斜视图fullsectionalviews:全剖视图halfsectionalviews:半剖视图localsectionalviews:局部剖视图cut-awayviewscross-sections:断面图revolvedcross-sections：重合断面图removedcross-sections:移出断面图localenlargedviews(details):局部放大图viewsofsymmetricalparts:对称机件的视图principalviews:基本视图referencearrowviews：向视图2.1 孔（HOLE）如：（1）毛坯孔：3"DIA0+1CORE芯子3"0+1;（2）加工孔：1"DIA1";（3）锪孔：锪孔(注C＇BORE=COUNTERBORE锪底面孔);（4）铰孔：1"/4DIAREAM铰孔1"/4;（5）螺纹孔的标注一般要表示出螺纹的直径，每英寸牙数（螺矩）、螺纹种类、精度等级、钻深、攻深，方向等。
1 典型外贸图纸及读图要点
C、图纸版次更改栏
图纸版次更改栏的内容相对简单，一般包括修改版次号、更 改单号或更改说明、更改日期等内容。 下图为一具体件号的图纸版次更改栏，供参考。
D、应用规范栏
应用规范栏也称作适用技术规范栏，用于注明制造该零件所要用到的规范 （或技术文件）。一般设计图都有专门的应用规范栏（或技术规范栏），也 有的设计图将其列入图纸的注释当中。 下列为GEAE某零件图纸注释（技术条件）的一部分。在注释1中标明了必 须符合的技术条件。
标题栏实例。
图文说明： Finish or treatment – 光饰或处理 Material: high strength, non magnetic stainless steel to conform to SH 620512. Material certification to be supplied with component. 材料：符合SH 620512的高强度无磁不锈钢。材料证书应与零部件一起提供。 90°countersink all tapped holes to major diameter of threads +0.25 对所有螺纹孔锪90°锥口孔，螺纹大径公差+0.25 Start and finish angle on machine threads to be 45°±15° 机加螺纹的起始和终止角度为45°±15° Surface finish 表面粗糙度 Remove burrs and break corners R0.2 max 去毛刺并倒圆R0.2最大 Inside corner R0.25 max 内角R0.25最大 Total runout T.I.M 0.1 总跳动总指示器测量值0.1 Units: MM – 单位：厘米 Angular tolerance – 角度公差 Dimension tolerance – 尺寸公差 Title: Bias unit body –名称：偏置件 DWG revision – 图纸版次
机械制图工程图及公差与配合
28
200
228
A-A 16.5
3.2
B 0.05 B
技术要求
1.调 质 220～ 250HB。 2.未 注 倒 角 均 为 C2。 3.去 锐 边 毛 刺 。
齿轮轴
比例 件数 1
（图号）
4.线 性 尺 寸 未 注 公 差 为 GB/T1804-m。 班 级
(学 号 ) 材 料 45 成 绩
制图 审核
外壁沿拔模方向应设计成具有一定的斜度，称为拔模斜度。
斜度 斜度
斜度 斜度
拔模方向尺寸在25～ 500mm的铸件，其拔模斜度约 为1：20～1：9（3°～6°）。拔 模斜度的大小也可从有关手册中 查得
在零件图上，零件的拔 模斜度若无特殊要求时， 可以不画出，也不加任 何标注。
92.6.1.1.2.2..铸铸件件结结构构的的要要求求 3．铸件壁厚应均匀或逐渐过渡
常见零件 结构特点 表达方法
9.32.2轮.轮盘盘类类零零件件
包括齿轮、手轮、皮带轮、飞轮、法兰盘、端盖等。
其主体一般也由直径不同的回转体组成， 径向尺寸比轴向尺寸大。常有退刀槽、凸台、 凹坑、倒角、圆角、轮齿、轮辐、筋板、螺孔、 键槽和作为定位或连接用孔等结构。
1.非圆视图水平摆放作为主视图。（常剖开绘制） 2.用左视图或右视图来表达轮盘上连接孔或轮辐、 筋板等的数目和分布情况。 3.用局部视图、局部剖视、断面图、局部放大图 等作为补充。
缩孔 逐渐过度
裂纹
壁厚均匀
缩孔
逐渐过度 裂纹
缩孔
逐渐过度 裂纹
壁厚不同应 逐渐过渡
铸件壁厚处 理不当可能 产生的缺陷
9.2.2.机械加工工艺对零件结构的要求
1、倒角和倒圆
机械制图尺寸标注方法
（1）在装配图上的标注——基孔制 基本尺寸基准孔基本偏差代号、标准公差等级 轴的基本偏差代号、标准公差等级
图中：
为基孔制过渡配合
为基孔制间隙配合
（1）在装配图上的标注——基轴制 基本尺寸 孔的基本偏差代号、标准公差等级
基准轴的基本偏差代号、标准公差等级
IT01等级最高，数值最小； IT18等级最低，数值最大。
• （2）基本偏差：用以确定公差带相对于零线位置的上偏
差或下偏差，一般指靠近零线的那个偏差称为基本偏差。
若公差带位于零线之上，下偏差是它的基本偏差； 若公差带位于零线之下，上偏差是它的基本偏差。
二、配合 1、定义：基本尺寸相同的孔与轴装配在一起，叫做
孔 >50-250
0.80
>30-250
>250-500 1.60
>250-500
Ra (μm) 0.40 0.80 1.60 0.40 0.80 1.60 0.40 0.80 1.60 3.20
续表
公差 等级
基本尺寸
<6
轴 IT9 和 >6-120
孔 >120-400
>400-500
<10
>10-120
所示：
回首页
yi
轮廓算术平均偏差Ra的数值
Ra 1 l y(x)dx l0
或近似表达
Ra 1 n yi
n i1
轮廓算术平均偏差Ra的数值
第一 第二 系列 系列
0.008 0.010
0.012 0.025 0.050
0.016 0.020
0.032 0.040
0.100
(完整版)英文机械图纸
1 标题栏英文工程图纸的右下边是标题栏（相当于我们的标题栏和部分技术要求），其中有图纸名称（TILE）、设计者（DRAWN）、审查者（CHECKED）、材料（MATERIAL）、日期（DATE）、比例（SCAL E）、热处理（HEAT TREATMENT）版本号(REVISION缩写REV) 工程变更号:E.C.N 页码(SHEET) 技术要求(NOTES）图号(DRAWING NO/P ART NO.）和其它一些技术要求，如：1)TOLERANCES UNLESS OTHERWISE SPECIFIAL 未注公差。
2)DIMS IN mm UNLESS STATED 如不做特殊要求以毫米为单位。
3)ANGULAR TOLERANCE±1° 角度公差±1°。
4)DIMS TOLERANCE±0.1 未注尺寸公差±0.1。
5)SURFACE FINISH 3.2 UNLESS STATED 未注粗糙度3.2。
not specified surface roughness is ra 6.3my 没有指定的表面粗糙度Ra 6.3 my6)40 REF 尺寸为40，参考值7）410 OPENING REF 410 开口参考尺寸8）2.5” BSP 2.5”圆锥管螺纹9）TYP 2 POSNS 2处10）OD 1/4’ outside dimension 1/4’的缩写外径值1/4’---应该为:外径值1/4”11）ALL UNSPECIFED PADI-R3 未注圆角R312）TYP CAST RADLL R9.7 未注铸造R9.713）REMOVE ALL BURRS AND SHARP EDGES 棱角倒钝14)STAMP 1/4 LETTERS DWG DT14331 PO刻1/4字图号定单号15)alternative astm b763 c99500 翻译替代材质 b763 c995 0016)UNLESS OTERWISE SPECIFIED 除非指定的17)LEADED RED BRASS:UNS C83600 TO ASTM B584，ALTERMATIV E,ASTM B763，C99500 含铅红黄铜:牌号号,B584 C83600 ASTM,也可以用此片号替代,ASTM,C99500 B763 18)no marking 没有标记19)2.5" BSPT HEXAGON 2.5” 六角圆锥管螺纹(即对丝)20)CHAMFERS NOT DIM 未注倒角21)not specified pattern draft 没有指定拔模22)all sharp edges and burrs are to be removed 清除所有的锐边和毛刺 23)measunng is in mm 测量单位为毫米MM 24）1.Dimensional tolerances unless otherwise specifie d:One Place------------------+-0.5Two place------------------+-0.30Angles----------------------+-1.0度1..除特别说明外，尺寸公差应小于：１级－－－－－－－－±０.５２级－－－－－－－－±０.３角度－－－－－－－－１°25）2. Casting tolerances apply to the location of cast outline featureslocated with basic dimensions２.铸造公差适用于具有基准尺寸的铸件轮廓特征区域；26）3．Casting to be free from oil,grit,dirt and loose particles. ３.铸件（表面）须经除油、除尘、除锈和喷砂处理；27）4．Porosity holes to be max 2.3 diameter by 1.6 dee p.４.砂眼孔最大不能超过直径2.3，深度1.6；28）5. casting quality to conform with general motors s tandards and specifications.５.铸件的质量应符合通用汽车（GM）的标准和技术说明书；29）6. Casting tolerances are not cumulative.６.铸件误差不累积； 30）7.casting tolerances unless oth erwise specified:0.0 to 75.0 ------------------------------- +-0.7575.0 to 200.0 ---------------------------- +-1.15draft angles ------------------------------2度fillet radii --------------------------------3.0corner radii ------------------------------3.0all walls & ribs ------------------------- 4.57.无特殊说明时，铸造公差应小于：０.０～７５.０－－－－－－±０.７５７５.０～２００.０－－－－±１.１５拔模角度－－－－－－－－－２°内圆角半径－－－－－－－－３外圆角半径－－－－－－－－３所有壁板和筋厚－－－－－－４.５31）8.Material cast iron per GM274M grade 2058.材料：铸铁依照GM274M 等级 205；32）9.restricted and reportable substances for parts pe r GMW 30599.零件中的限制物质和必须明示的物质（环保要求）依照标准G MW 3059;33）10.Must comply with QP-I.6-009 for production and Q P-I.6-004 for Prototypes.10.必须依照QP-6.I-009产品和QP-I.6-004原型生产34）Machining allowance to be adopted when turning a su rface to be ground is equal to Max value for required dimen sion with 0.05 mm deviation表达的是加工后基本尺寸的上下偏差，就是±0.0534）METARIAL : ALLOY 24, PERMOLD.1,材质：合金24，由模具成型。
机械制图：粗糙度介绍
第三篇粗糙度介绍
【教学课题】§3.1 认识粗糙度
【教学目标】
1. 知识与技能：
（1）知道粗糙度的职能、了解粗糙度的概念以及粗糙度是如何产生的；
（2）能够在图纸上标注粗糙度，了解测量粗糙度的方法；
（3）能够根据粗糙度符号说出它所代表的含义；
2. 过程与方法：通过情景引入进入课堂，辅以任务驱动，同时运用讲故事的方法，完成教学任务，培养学生的想象能力和学习能力，体现将品德教育融入到教育教学中的思想。
3. 情感态度价值观：培养学生的学习兴趣、自信心和口头表达能力。
【教学重点】粗糙度的表示方法；
【教学难点】粗糙度在图纸上的识读与标注；
【教学方法】
1. 教法：任务驱动、学生回答问题、举例子
2. 学法：做中学，学中做
【教学准备】
教学详案、投影仪、多媒体课件等。
【教学时间】1课时
【教学过程】
一、温故知新（5分钟）
二、新课引入（20分钟）
三、课堂小结与作业（5分钟）
1. 小结
师：好，本堂课我们复习了上堂课的内容，同时给大家介绍了粗糙度的概念及原理及测量方法。
希望同学们喜欢这堂课。
师：好，本堂课最后一个内容，记一下课后作业。
写好一起交上来。
2. 作业
任务单的内容，书本P20页想想练练。
【板书设计】
【教学反思】。
识读零件图的技术要求
识读零件图的技术要求
四、表面粗糙度
4．表面粗糙度在图样上的标注方法 （1）表面粗糙度代（符）号应注在可见轮廓线、尺寸线、尺寸 界线或它们的延长线上，符号的尖端必须从材料外指向零件表 面，如图4-19、图4-20所示。 （2）在同一张图样上，每一表面一般只标注一次表面粗糙度代 （符）号，并尽量靠近尺寸线，若地位狭小或不便标注时也可 引出标注，如图4-21所示。 （3）符号的标注方向必须按图4-21规定的方向标注。 （4）当零件的大部分表面具有相同的表面粗糙度要求时，对其 中使用最多的一种代（符）号可统一标注在图样右上角，并加 注“其余”两字，如图4-19、图4-20所示。
识读零件图的技术要求 四、表面粗糙度
汽车机械基础
识读零件图的技术要求
任务分析：
一张完整的零件图，包括四大块内容：一组图 形、完整的尺寸、标题栏、技术要求，前三者我们 都熟悉，但还有好多我们不认识的符号和标记。这 一类我们不认识的符号和标记就称为技术要求，这 一类技术要求包括零件表面粗糙度、零件极限尺寸 与配合要求、零件的形状和位置公差，零件材料的 要求、加工要求、热处理和表面处理的说明等。
识读零件图的技术要求
一、公差与配合的基本概念
2、标准公差与基本偏差
识读零件图的技术要求
一、公差与配合的基本概念
3、配合 基本尺寸相同的，相互结合的孔和轴公差带之
间的关系称为配合。任何两个零件当分别以孔和轴 的不同形式相配合时，其配合性质有两种：间隙和 过盈。根据孔、轴公差带之间的关系，国家标准规 定配合有三种类型。
经过加工的零件表面，不但会有尺寸误差，而 且也会有形状和位置误差。对于精度要求较高的零 件，要规定其表面形状和相互位置的公差，简称形 位公差。 1、形位公差种类
lxg表面粗糙度
Int J Adv Manuf Technol(2000)16:668–674©2000Springer-Verlag LondonLimitedAutomated Surface Roughness MeasurementC.BradleyDepartment of Mechanical Engineering,University of Victoria,Victoria,CanadaA non-contact roughness sensor is described that is suited for integration with a computer-controlled coordinate measuring machine(CMM).The sensor employs afibre optic interfer-ometer,electronic control system and data-processing software. The combination of the sensor and computer controlled CMM allows surface texture assessment to be made during scheduled dimensional inspections of complex curved surface components, such as turbine blades.The sensor system will measure surface roughness parameters,for example R a,using a method that reflects standard procedures.The lightweight sensor head can be mounted on a touch probe arm and the associated articu-lated mounting head;this combination gives quasi5-axis positioning ability to the overall sensor.This is suitable for automated surfacefinish inspection of compound curved surface blades.The sensor and its control unit are integrated with the CMM controller and its operation can be controlled through standard part-program commands used by the CMM. Keywords:Automated inspection;Coordinate measuring machine;Fibre optic sensor;Surface texture1.IntroductionThis paper describes an optical surface texture sensor that is integrated with a computer numerically controlled(CNC) coordinate measuring machine(CMM).The combination of the two technologies permits the measurement of both dimen-sional and roughness metrics on a part placed on the deck of the CMM.1.1Literature ReviewThe demand for incorporating sensor technology into the production environment is being driven by the simultaneous need to minimise manufacturing costs while maintaining a high standard of quality[1].In particular,new surface texture Correspondence and offprint requests to:Dr C.Bradley,Department of Mechanical Engineering,University of Victoria,PO Box3055, Victoria BC,V8W3P6,Canada.E-mail:cbrȰengr.uvic.ca sensors have predominantly been non-contact,employing optical,ultrasonic,and capacitance methods[2–5].The sensors typically measure a common surface roughness parameter,such as the average roughness amplitude or R a.This work presents an optical texture sensor,employingfibre optics,that is physi-cally compact and lightweight making it ideal for integration with a CMM.Previous research on usingfibre optics in surface roughness measurement was performed by Spurgeon and Slater [6]and by Lin et al.[7].Both used a bundle of opticalfibres to deliver light to the surface and also to collect the reflected light and guide it to a photo detector.A correlation was found between the intensity of the reflected light(as measured by the photo detector)and the average roughness of the surface. However,both techniques suffered from changes in the reflected light intensity owing to varying reflectance properties of the surface under inspection.The measurements also lacked sufficient sensitivity and were only suitable for measurements on smooth surfaces up to R a=0.5m.North and Agarwal [8]circumvented both of these problems by using twofibre optic bundles,which illuminated the surface at two angles of incidence.The ratio of the two reflected light intensities removed the problem of surface reflectivity variation.The instrument showed good correlation with stylus measurements, up to R a=1m.Thefibre optic sensors described above do not provide surface profile data;they simply correlate the collected light intensity with the R a measured by a stylus.The fibre optic sensor described below alleviates the problems stated above.1.2BackgroundThere is a range of high-value,geometrically complex,and dimensionally precise components that are typically inspected on a programmable CMM.For example,turbine blade assemblies,machined on multi-axis CNC machine tools,must meet dimensional and surfacefinish specifications before they are approved and incorporated into thefinal product.A surface roughness specification(usually R a or R z)is mandatory,owing to the effect that surface texture has on the efficiency of the airflow over the blade surface.As an example,Fig.1shows a turbine CAD model from which a CMM inspection part program is typically derived.The CMM controller uses theAutomated Surface Roughness Measurement669Fig.1.(a)Shaded image of turbine assembly;blades plus hub.(b) CAD model of turbine assembly composed of parametric curve and surface entities.part program to move the touch probe around the component and perform the spatial measurement at each required location. Thefigure illustrates the geometric complexity of the part; each blade can have several machining patches,corresponding to different cutting tool orientations,generated during milling. The component is then removed from the CMM table and a sequence of surface roughness measurements is then made on all blade surfaces.The surface roughness is measured using a manually operated stylus instrument and the R a or R z values are noted for each position.Several R a values are collected from each patch along the length of the blade.The exact location of the measurement is not critical to the result;how-ever,several representative roughness values from each patch are necessary.Inspection efficiency for this type of component could be enhanced by automating the surface texture measure-ment as well as the dimensional measurements.A surface roughness sensor system that can be integrated with a CMM would be desirable and should have the following character-istics:The sensor head must be physically compact and able to perform roughness measurements on compound curved sur-faces.The sensor head must be lightweight and suitable for attach-ment on a CMM probe articulating head(e.g.a Renishaw PH10probe head).The sensor’s operating parameters must be compatible with a stylus profilometer and have a measurement range of0.10ϽR aϽ20with a0.10m resolution.The component must remainfixed in the same position,on the CMM,during both dimensional and surface roughness measure-ments.The roughness sensor probe head,data processing software and electronic control unit must be transparent to the CMM controller. The motion of the sensor head must be under the control of the CMM using a standard inspection part program.2.Sensor OperationThe details concerning the operation of the sensor head as an interferometric cavity have been previously reported[9,10]. The essential component of the overall sensor is the head, illustrated in Fig.2,which is comprised of a single modefibre attached to a cylindrical graded-index(GRIN)lens.The lens focuses the incoming light wave(),from thefibre,onto the part surface at a stand-off distance of approximately5.0mm from the lens front face.The front face of the lens is coated with a partially reflective material and divides the incoming light wave into two components:1.Wave A1,having10%of the original intensity,that isreflected from the lens front face and which travels back down thefibre.2.Wave A2,the transmitted portion that is focused onto thetarget surface and then collected by the GRIN lens and re-focused back down thefibre.The intervening surface profile difference,(d2−d1),is meas-ured from the phase difference of the two reflected waves by the principle ofinterferometry.Fig.2.Cut-away view of the sensor head details showing mounting block and GRIN lens.670 C.BradleyFig.3.A complete surface texture profile obtained by translating the sensor over one sampling length by means of the CMM system.The sensor,measuring a surface over a sampling length S between the start position A and the end position A Ј,is depicted in Fig.3.A digitised surface profile is generated that consists of a set of surface profile samples {(x i ,z i ):i =1,%,N }.The figure shows the mean reference line placed through the digitised data set.The sensor speed can be accurately set by the CMM controller through the range 0.1–1.0mm s Ϫ1;a slow speed is necessary to prevent unwanted vibration of the sensor head.For a sensor data sampling rate of 1kHz and a sampling length of 1.4mm,the control software will acquire 14000data points.This is a larger data set than required,therefore,the control software permits data decimation (by factors of 10or 100)after scanning is complete.The selection of the sampling length depends on the type of surface under investigation.The relationship between relative phase shift,laser wavelength and path length difference is given by Eq.(1)and illustrated in Fig.4.The figure shows the sensor acquiring two consecutive measurements of surface profile,at Point 1and Point 2,respect-ively.As shown,the surface height change between the locations is (d 2−d 1).It is assumed in this example that (d 2−d 1)is less than half of the wavelength of the laser,or 0.4m.The change in optical phase shift between the two positions is:⌬=(2−1)2(d 2−d 1)(1)where,(d 2−d 1)=vertical distance between the positions of points1and 2⌬=phase difference between the waves reflected fromthe lens coating and the surface=wavelength of the laser (800nm or 0.8m)The interference intensity versus optical phase shift change (Eq.(1))is also shown in Fig.4.The variation of intensity,I ,for the displacement (d 2−d 1)is shown.If points 1and2Fig.4.Determination of surface height from the sensor’s intensity profile for two points less than 0.85m vertically apart.are positioned as shown on the intensity function,then the movements of the corresponding interference intensity values are C and E .The phase shift measured by the sensor elec-tronics,⌬1,is also indicated.Therefore,phase shift or surface height variation can be accurately determined provided the total distance change (from lens to surface and back to lens)does not exceed 0.4m.This value is obtained by rearranging Eq.(1)and using the laser wavelength of =0.8m.The maximum intensity (I max )is attained when there is zero or 2phase shift between A 1and A 2.These are the so-called maximum brightness fringes in standard interferometer nomenclature.Monitoring of I ,between the brightness fringes (fringe 0,fringe 1,fringe 2,etc.)allows the determination of surface profile.Now consider the situation illustrated in Fig.5,where the sensor moves over the surface,from point 1to point 2,and the surface height varies by more than 0.4m.To accommo-date larger surface height variations,the sensor tracks the number of brightness fringes that pass a given reference point,denoted by D in the figures.Therefore,as the sensor moves from point 1to point 2,through a vertical drop of (d 2−d 1)=0.85m,the sensor tracks 2fringes or 0.80m of vertical drop.Reference to Fig.5shows that “fringe 1”and “fringe 2”have passed the reference point D relative to the starting point given in Fig.4.The electronic sensor counts the fringes that pass the reference point and then measures the intensity in the last fringe.As shown,the remaining phase ⌬2isAutomated Surface Roughness Measurement671Fig.5.The fringe-counting method for determining the vertical height between two points greater than 0.85m apart.monitored on the photo detector by the increase in intensityfrom I Ј1to I Ј2.This measurement corresponds to the remaining 0.05m of vertical profile drop.Employing the fringe tracking method,larger variations in surface topography can also be measured.Therefore,the sensor provides two output signals to the data acquisition system and supervisory control software:1.A subfringe signal capable of resolving surface detail to one hundredth of an interference fringe,or 4nm.2.A fringe counting signal that monitors the larger scale variations in surface topography.The two signals are processed by the software to generate a surface profile of the part,over the sampling length,from which surface roughness amplitude parameters,such as R a and R z can be calculated.3.Integration of the Sensor System with a CMMThe major integration issues inherent in combining the fibre optic sensor with the CMM (Mitutoyo BH10M)are highlighted in Fig.6,which illustrates the main components and the data flow inter-connections.3.1Mounting the Sensor Head on the CMMThe mounting of the sensor head on the CMM,the electronic control unit and the software user interface are shown in Fig.7.The physical dimensions of the sensor probe headare:Fig.6.Schematic diagram showing the inter-connection of the main components.Sensor head length 8.0mm Sensor head diameter 5.0mm Fibre optic length up to 4.0m Fibre optic diameter 2.5mmThe sensor is attached to a touch probe head by means of an extension arm.The extension fits the probe-articulating head at one end,and provides a mounting barrel for the GRIN lens at the other.The combination of sensor and articulating head allows flexibility for positioning the sensor relative to the surface of an object.The articulating head allows positioning in 7.5°increments in both of the rotational axes.Overall,this approximates to 5-axis computer control of the sensor head location.This capability is crucial to successful operation of the fibre optic sensor system.The axis of the sensor’s GRIN lens must be maintained at a perpendicular orientation to the object surface during the surface scanning operation.If the object is a compound curved surface,the sensor head must have 5-axis positioning capability.Each position of the articul-ating head is qualified during the measurement procedure rela-tive to a reference sphere placed on the probe tip holder rack.Qualification of the sensor probe position is a standard pro-cedure when using an articulating probe head on a computer controlled CMM.3.2Synchronisation of the CMM and Sensor SystemThe commencement of a surface roughness data acquisition scan is synchronised with the motion of the CMM’s servo-motors.The synchronisation method is outlined below and illustrated in Fig.8:The CMM inspection program positions the sensor head at a measurement location above the object’s surface at the correct stand-off.The articulated head’s two angular positions are adjusted to position the sensor head perpendicular to the surface,see Fig.9.The sensor head is moved along the evaluation length (a distance of approximately 5.00mm)as data is gathered by the electronic control unit.During the scan,the position feedback sensors,on each axis of the CMM,provide axial position data to the CMM control unit (see Fig.8).The feedback dataisFig.7.Photograph of the sensor (mounted on the CMM arm)with the control unit and personal computer data interface.672 C.BradleyFig.8.Velocity profile of the CMM,in one axis,and the corresponding scale feedback related to the data acquisition timing of thesensor.Fig.9.Position of the sensor head relative to the blade surface.available as an a-quad-b signal (digital pulse signals specifying motor movement and direction)where each pulse corresponds to the smallest distance increment that the CMM can move (for example,1m).This signal is accessed,for all the motor-scale combinations,and input to the sensor data acquisition board to serve as an axial distance measuring signal.Figure 8illustrates the CMM scale signal that is used to measure precisely the distance over which roughness data is acquired.The a-quad-b pulse train is shown for one of the measurement segments,R a 5.Figure 8also shows the entire trapezoidal velocity profile for the CMM motion.The a-quad-b signal is employed to define each of the measurement segments,R a 1to R a 6,in this manner.An RS 232synchronisation signal,triggered by the CMM inspection part program,initiates the data collection process in the electronic control unit.Once the CMM arm (moving in one axis only)has attained a constant velocity,the data acqui-sition ing the a-quad-b signal,the data acquisition software measures off the 6sampling lengths as shown.Each sampling length is a distance equivalent to (0.8×c ).The R a is calculated for five sampling lengths (R a 1,R a 2,%,R a 5)and an average surface roughness value,R ave ,is calculated over the first five sample lengths.This average value is then checked against R a 6,calculated over the sixth sampling length.After the predetermined distance has been moved by the sensor,the CMM decelerates as shown in the diagram.Using this technique,the data acquisition card can calculate an R a value that corresponds to accepted standards.4.Determination of Surface Profile Amplitude ParametersThe necessary steps for processing the sensor data and generat-ing the surface texture amplitude parameters are described below.The entire data acquisition and processing system has been implemented on a Windows based National Instruments LabView system.The data acquisition card is of the DIO-96type and all the data processing algorithms,outlined below,have been implemented in the LabView environment.4.1Sensor Control and Data AcquisitionThe software user interface allows the data collection para-meters to be set before commencing a surface roughness scan.The parameters are the translation speed of the CMM arm over the object surface,the sampling length,start location,stand-off distance of the sensor head above the object and the data sampling rate of the electronic control unit.The interface also synchronises the commencement of sensor data acquisition with the movement of the CMM arm as discussed above.In particular,the software ensures that no data is collected during the acceleration and deceleration phases of the CMM arm.The data produced by the sensor electronic control unit has two components:1.A digital signal representing the distance from the lens to the surface expressed as a fraction of the current interfer-ometer fringe.2.A digital signal that tracks the current fringe number from the commencement of the scanning operation.The combination of both data sets represents the actual height value between the lens and the surface under inspection.The control software converts each data pair into a value expressed in micrometres based on the known value of the laser wave-length (0.80m),and each value is stored in the computer memory until the acquisition process is complete.The data is then written to a data file and graphed on the control software interface.4.2Surface Profile Data ProcessingTwo initial processing steps are performed before the surface roughness amplitude parameters are calculated.First,the data is filtered to remove high-frequency noise and second;a refer-ence line is determined from which the amplitude parameters are subsequently determined.Figure 10(a )illustrates the unfil-tered sensor signal obtained when it remains stationary over the same surface location for approximately 0.5s.This sensor noise can be attributed to the air bearing flutter of the CMM gantry and it exhibits a normal distribution about the expected straight line.The noise is removed from the original data before further calculations are performed.The texture profileAutomated Surface Roughness Measurement673Fig.10.(a)Unfiltered surface profile acquired with the sensor system.(b)Effects of air bearingflutter removed from the surface profile using softwarefiltering.shown in Fig.10(b)illustrates the effect of datafiltering.In Fig.10(b),the dashed line illustrates the surface profile before filtering,whereas the solid line represents thefiltered profile. The additional detail evident in the dashed line is clearly an effect of the sensor system and is not representative of the process employed to manufacture the surface.Furthermore,this high-frequency component would not be detectable with the diameter of the laser spot generated by the GRIN lens.A low-frequency bandpassfilter was designed using a set of representative surface profiles.The higher-frequency sensor noise was clearly distinguishable from the surface profile data when these data sets were examined in the frequency domain. Surface roughness amplitude parameters are determined relative to a mean reference line that is located vertically,with respect to the profile,such that the profile area enclosed above the line is equal to that below it(see Whitehouse[11]for details on the mean line calculation).4.3Calculation of the Profile Amplitude Parameters The most common amplitude measure is R a(roughness average)defined relative to the mean reference line.It is the mean departure of the profile from the reference line and is given byR a=1nn i=1͉z i͉(2)Fig.11.Flowchart of the steps in acquiring a surface scan of rough-nessdata.Fig.12.Plan view of CMM deck with rotary table,component andsensor.In Eq.(2),n represents the number of data points collectedand z i the amplitude value at each measurement location.5.Performance of the Surface Profile SensorThe procedure for performing automated surface roughnessmeasurements,on a freeform surface part,is outlined in theflowchart of Fig.11.A turbine blade assembly(similar to theone shown in Fig.1)was employed as the test object.Theassembly was mounted on a rotary table,attached to the deck ofthe CMM,as shown in Fig.12.Each blade can be sequentiallypositioned under the CMM gantry allowing the sensor to movein a single axial direction.The details of the sensor positioningstrategy are as follows:For a new component,the starting point for each of therequired surface roughness measurement profiles is defined.674 C.BradleyThe CMM touch probe is used,in conjunction with the inspec-tion software,to create a part program(for thefibre optic sensor)that has all of the start points defined on the surfaces of the turbine blade.This procedure defines a new CMM inspection part program for the turbine.Commence surface roughness measurements on each blade using the start locations defined above.The sensor head is positioned at the start location at the correct stand-off distance (5.0mm)and with the correct orientation relative to the surface of the blade.The blade surface over each short5.00mm path length very closely approximates to a ruled surface.Therefore, the surface deviation(relative to the sensor head front face) will be minimal and well within the operating range of the interferometer.The CMM traverses the sensor head over the5.00mm evalu-ation length to the end position,at which point the CMM moves to the next location on the blade,or to another blade. The position of the articulated probe head is requalified every time it is positioned at a new angular position.Requalification is performed relative to a datum sphere positioned in the workspace of the CMM.The rotary table positions each blade,relative to the CMM gantry,so that only one CMM axis is in motion during a profile measurement,see Fig.12.This maintains a constant CMM velocity and reduces deviation from a straight-line tra-jectory.The maximum speed of the CMM is500mm s−1,and this can be varied,using software commands,from0%to 100%of the maximum.The maximum acceleration is1000 mm s2,and again this can be varied from0%to100%of the maximum,using the CMM software.A surface roughness measurement is activated from the CMM part program by a custom command.The command outputs a TTL high signal,via a standard RS232port,to the data acquisition card,whenever a surfacefinish measurement is required.The“acquire surface roughness data”command is inserted into a part program immediately prior to the move command.The CMM moves twice the required distance and the sensor software uses the middle section of the traverse as the constant velocity section.This is accomplished in the data acquisition card software using the CMM velocity and the scale signals from the controller.6.DiscussionThefibre-optic-sensor-generated profiles do not have quite the same level of detail as the stylus profiles because of the laser spot size incident on the surface.The spot size of the laser is a critical factor in the sensor operation and,unlike the stylus tip diameter which is afixed parameter,varies in effective diameter with changing surface profile height.The stand-off distance between the surface and the lens is nominally5mm. If the lens moves closer to,or further away from,the surface than5mm,then the spot diameter increases from its minimum value.At a stand-off of5mm,the diameter is estimated to be20m,which is larger than the stylus tip radius and responsible for the resulting loss in thefiner surface detail. This“convolution effect”results in smoother looking profiles than for the stylus profiles.Another contributing factor is the reflection of light back into the probe from either the centre or the perimeter of the spot.If the interference condition is met,the distance recorded will be from the strongest reflected signal.For example,in a sharp gap the strongest reflected signal occurs from the gap sides rather than the centre.A similar situation occurs for a sharp peak because more light can be reflected back into the probe from either side of the peak rather than the top of the peak. AcknowledgementsSincere thanks to Mr I.Archibald for assistance with the CMM programming and mounting thefibre optic head on the Z-axis arm.Thanks are also extended to Mr M.Failes for initial sensor development and Dr B.Hedstrom for developing the data acquisition software.References1.G.Byrne,D.Dornfeld,I.Inasaki,G.Ketteler,W.Konig and R.Teti,“Tool condition monitoring(TCM)–the status of research and industrial application”,Annals CIRP,44(2),pp.541–562, 1995.2.T.V.Vorburger and E.C.Teague,“Optical techniques for on-line measurement of surfacefinish”,Precision Engineering,3(2), pp.61–83,1981.3.H.K.Tonshoff,H.Janocha and M.Seidel,“Image processingin a production environment”,Annals CIRP,37(2),pp.579–589,1988.4.Y. C.Shin,S.J.Oh and S. A.Coker,“Surface roughnessmeasurement by ultrasonic sensing for in-process monitoring”, ASME Journal of Engineering for Industry,117,pp.439–447, 1995.5.J.L.Garbini,S.-P.Koh,J.E.Jorgensen and M.Ramulu,“Surfaceprofile measurement during turning using fringe-field capacitive prolifometery”,ASME Journal of Engineering for Industry,114, pp.234–243,1992.6.D.Spurgeon and R.A.C.Slater,“In-process indication of surfaceroughness using afibre-optics transducer”,Proceedings15th Inter-national Machine Tool Design and Research,15,pp.339–347, 1974.7.G. C.Lin,T.Shea and K.Hoang,“Measurement of surfaceroughness with a laser beam”,Australian Conference on Manufac-turing Engineering,pp.132–133,1977.8.W.P.T.North and A.K.Agarwal,“Surface roughness measure-ment withfibre-optics,technical brief”,ASME Journal of Dynamic Systems,Measurement,and Control,105,pp.295–297,1983. 9.C.Bradley,J.Bohlmann and S.Kurada,“Afibre optic sensor forsurface roughnesss measurement”,ASME Transactions,Journal of Manufacturing Science and Engineering,120,pp.359–367,1998. 10.J.Bohlmann and C.Bradley,“Afibre optic interferometer for themeasurement of surface topography”,COMADEM95,Kingston, Ontario,June1995.11.D.J.Whitehouse,Handbook of Surface Metrology,Institute ofPhysics Publishing,Bristol,1994.。
浅谈英文图纸读图的一些关键点
浅谈英文图纸读图的一些关键点王永泉任柏林罗宁张桂英(湖北汽车工业学院机械工程系，湖北十堰442002 )摘要：根据作者英文图纸看图的一些经验及查阅有关资料，总结出了英文工程图纸读图的一些关键点。
按照看图的顺序简要介绍了标题栏、表达方法、尺寸标注、技术要求、常见加工工艺看图的一些方法及常用词汇的中文翻译。
为工程技术人员快速读懂英文图纸提供了参考。
关键词：英文图纸；读图；翻译；关键点中图分类号：TH126文献标识码：AA Discussion of Some Key Points about Interpreting English BlueprintsWANG Yong-quan, REN Bai-lin, LUO Ning, ZHANG Gui-ying（HuBei Automotive Industries Institute, Shiyan 442002, Hubei Province, China）Abstract : According to author’s some experiences about interpreting English drawings and some connected materials, the article summarized some key points about interpreting English drawings. In interpreting drawings order, title, representation of drawings, dimensioning, technical requirement were introduced simply. Chinese translations of some often seen English words in engineering drawings were given, and some common manufacturing crafts in English were also translated into Chinese. References were provided for the technical personnel interpreting drawings quickly.Key words: English blueprints; interpreting drawings; translation; key points1.前言随着加入WTO，国外的设备、图纸及其他技术资料大量的涌入我国。
识图及三视图
柱
多样形反映该形体的特征。
体
2、锥（台）体三视图与锥（台）体三视图的识读
图例
说明
圆锥体的三视图有一个反映锥体底面
圆
实形的投影和两个外轮廓为相同等腰三角
锥
形的投影，三角形的顶点是一个点（锥顶）
体
的投影。
棱锥体的三视图有一个反映锥体底面
棱
的投影和两个外轮廓为三角形的投影，三
锥
角形的顶点是一个点（锥顶）的投影，三
第一部分 机械识图
第1章 第2章 第3章 第4章
识图的基本知识 图样基本表示法 零件图 装配图的识读
第1章 识图的基本知识
1.1 机械图样 1.2 识图的基本知识 1.3 斜度和锥度 1.4 投影规律 1.5 基本体三视图识读 1.6 组合体三视图识读
1.1 机械图样
图样：工程技术上根据投影方法并遵照国家标准的规定绘 制成的用于工程施工或产品制造等用途的图叫做工程图样， 简称图样。 机械制造业所使用的图样称为机械图样， 图样是工程技术人员借以表达和交流技术思想不可缺少的 工程语言。
构成组合体的最小单元且不需要再分解的物体形状，叫做基本体。
1、柱体三视图与柱体三视图的识读 图例
说明
圆
圆柱体的三视图是由一个圆和两个
柱
矩形。
体
圆的投影反映该形体的特征。
棱
棱柱体的三视图是由一个正多边形
柱
和两个矩形。
体
多边形的投影反映该形体的特征。
一
一般柱体的三视图都是由一个
般
多样形和两个矩形来表述。
与锥高之比。如果是圆
锥 度
锥台则是上、下底圆直 径之差与锥台高度之比，
写成1：n的形式。
机械识图形位公差表面粗糙度11486
下面举例加以说明:
例1: 尺寸 此尺寸的基本尺寸为Φ10, 上偏差为
+0.05,下偏差为 -0.02,尺寸公差为0.07 (尺寸公差 = 最大极限尺寸–最小极限尺
寸)或(尺寸公差 = 上偏差–下偏差) 最大极限尺寸为Φ10.05,最小极限尺寸为
A向 A
四、局部视图
局部视图是 将物体的某 一部分向某 基本投影面 投射所得到 的视图,如下 图所示。
A A
五、斜视图
斜视图是 将物体向 不平行于 任何一个 基本投影 面的平面 投影所得 的视图,如 下图所示。
B B
或
六、旋转视图
有的机件部分结构倾斜于基本投影面,且 该结构具有回转轴线,在画图时,为了能反 映倾斜部分的真实结构,可假想将倾斜部 分绕回转轴线旋转到与基本投影面平行 的位置,再进行投影所得到的视图称为旋 转视图,如下图所示。
下偏差为-0.5,尺寸公差和0.5,最大极限尺
寸为20.00,最小极
限尺寸为19.50,
从以上的实例可以看出,上下偏差可
以为正值,也可以为负值,还可以为0,但是,
尺寸公差只能为正值,而不能为0和负值
第二节: 形位公差
(一) 形位误差 被测要素的实际形状对其理想形状的变
动量为形状误差,被测要素的实际位置对 其理想位置的变动量为位置误差,被测要 素的理想位置必须相对基准而定。形状 误差和位置误差和起来称为形位误差。 基准要素的理想形状称为基准。形位公 差是形位误差所允许的变动全量
Φ9.98,实际尺寸必须在Φ9.98到Φ10.05 之间才OK。
例2: 尺寸16±0.1
此尺寸的基本尺寸为16,上偏差为
+0.1,下偏差为-0.1,尺寸公差为0.2,最大
1 国外机械图纸常用的单词与缩写
国外机械图纸常用的单词与缩写1组织与标准国际标准化组织（旧称ISA）：ISO美国国家标准（旧称ASA）：ANSI英国标准：BS日本工业标准：JIS法国标准：NF德国标准：DIN澳大利亚标准：AS加拿大标准：CSA2常见图纸的标注及要求英文工程图纸的右下边是标题栏（相当于我们的标题栏和部分技术要求），其中有图纸名称（TILE）、设计者（DRAWN）、审查者（CHECKED）、材料（MATERIAL）、日期（DATE）、比例（SCALE）、热处理（HEATTREATMENT）和其它一些要求，如：1)TOLERANCESUNLESSOTHERWISESPECIFIAL未注公差。
2)DIMSINmmUNLESSSTATED如不做特殊要求以毫米为单位。
3)3)ANGULARTOLERANCE±1°角度公差±1°。
4)4)DIMSTOLERANCE±0.1未注尺寸公差±0.1。
5)5)SURFACEFINISH3.2UNLESSSTATED未注粗糙度3.2。
SCALE表示绘图比例。
ITEMNo.设备号或货号NOOFF件数STYLENo.型号DRG.No.图纸序号全称DrawingNumberSHEET:页码号或理解为第几页REVISIONNo:修订号DESIGNED&DRAWN:设计与制图签名处也有表示为DRAWNBY,简写为DWNDATE:日期MAT'L:材料也有简写为MATDESCRIPTION说明(或备注、名称)DIRECTORY\FILENAME:电子文档存放目录\文件名APPROVED批准签字简写为APPDCHECKED审核签字简写为CKDTRACED描图签字简写为TCDHeatTr热处理Donotscaledrawing不按比例绘制View:视图localviews:局部视图inclinedviews:斜视图fullsectionalviews:全剖视图halfsectionalviews:半剖视图localsectionalviews:局部剖视图cut-awayviewscross-sections:断面图revolvedcross-sections：重合断面图removedcross-sections:移出断面图localenlargedviews(details):局部放大图viewsofsymmetricalparts:对称机件的视图principalviews:基本视图referencearrowviews：向视图2.1 孔（HOLE）如：（1）毛坯孔：3"DIA0+1CORE芯子3"0+1;（2）加工孔：1"DIA1";（3）锪孔：锪孔(注C＇BORE=COUNTERBORE锪底面孔);（4）铰孔：1"/4DIAREAM铰孔1"/4;（5）螺纹孔的标注一般要表示出螺纹的直径，每英寸牙数（螺矩）、螺纹种类、精度等级、钻深、攻深，方向等。
如何快速看懂国外机械图纸 文档
机械图样-是专门研究绘制机械图样理论和方法。
是生产中最基本的技术文件；是设计、制造、检验、装配产品的依据；是进行科技交流的工程技术语言。
它的主要内容为一组用正投影法绘制成的机件视图，还有加工制造所需的尺寸和技术要求。
2、投影（1）投影的基本概念用灯光或日光照射物体，在地面或墙面上就会产生影子，这种现象就叫投影。
正投影-当投射线互相平行，并与投影面垂直时，物体在投影面上所得的投影叫正投影。
（2）三面视图-指物体在正投影面所得主视图、在水平投影面所得的俯视图、在侧投影面所得左视图的总称。
主视图-表示从物体的前方向后看的形状和长度、高度方向的尺寸以及左右、上下方向的位置。
俯视图-表示从物体上方向下俯视的形状和长度、宽度方向的尺寸以及左右、前后方向的位置。
左视图-表示从物体左方向右看的形状和宽度、高度方向的尺寸以及前后、上下方向的位置。
3、图纸视角（1）视角定义图样的画法-两种形式-“第一视角”和“第三视角”ISO国际标准规定-在表达机件结构中，第一角和第三角投影法同等有效。
我国则侧重第一角画法（英国、德国等），视角定义第一视角-是按人（观察者）－－物（机件）－－面（投影面）的相对位置，作正投影所得的图形的方法。
第三视角-是按人－－面－－物的相对位置关系，作正投影所得的图形的方法如何快速看懂国外机械图纸自改革开放以来，我引进了不少国外设备、图纸和其它技术资料，有不少发达国家的机械图样投影方法与我国所采用的投影方法不同。
为了更好地学习发达国家的先进技术，故快速看懂国外机械图纸很有必要。
1 概述当今世界上，ISO国际标准规定，第一角和第三角投影同等有效。
各国根据国情均有所侧重，其中俄罗斯、乌克兰、德国、罗马尼亚、捷克、斯洛伐克以及东欧等国均主要用第一角投影，而美国、日本、法国、英国、加拿大、瑞士、澳大利业、荷兰和墨西哥等国均主要用第三角投影。
解放前我国也采用第三角投影，新中国成立后改用第一角投影。
在引进的国外机械图样和科技书刊中经常会遇到第三角投影。
第四章 表面粗糙度
一、表面粗糙度轮廓的基本概念
表面粗糙度轮廓的界定
零件的表面总是存在一定程度的凹凸不平，即使 是看起来光滑的表面，经放大后观察，也会发现凹 凸不平的波峰波谷。零件表面轮廓上相邻峰谷间距 小于1mm的微观不平度称为表面粗糙度。
表面粗糙度产生的原因及影响
产生的原因有: 切削过程中的刀 痕、切屑分离时的塑性变形、刀 具和被加工表面间的摩擦、工艺 系统中的高频振动等。 ⑴影响零件的耐磨性 ⑵影响零件配合性质 ⑶影响零件的疲劳强度 ⑷影响零件的抗腐蚀性
评定参数的选择 评定参数值的确定
评定参数的选择
评定参数的选择：如无特殊要求，一般仅选用 幅度参数。推荐优先选用Ra值，因为Ra能充分 反映零件表面轮廓的特征。以下情况下例外： 当表面过于粗糙（Ra＞6.3）或过于光滑（ Ra ＜ 0.025）时，选用Rz。因为此范围便于选择 用于测量Rz的仪器测量。 当零件材料较软时，选用Rz。因为Ra一般采用 触针测量，在此条件下测量误差较大。
评定参数值的确定
选择原则：在满足零件表面功能要求的前提下，尽量 选取较大的参数值。 一般情况下，同一零件上，工作表面比非工作表面粗 糙度值小；摩擦表面比非摩擦表面要小；受循环载荷 的表面要小、配合要求高、联接要求可靠、受重载的 表面粗糙度值都应小；同一精度，小尺寸比大尺寸、 轴比孔的表面粗糙度值要小；一般尺寸公差、表面形 状公差小时，表面粗糙度参数值也小，。 常用表面粗糙度值与所适应的零件表面参看见P121表 5-2，选择时可进行类比。
第四章 表面粗糙度轮廓及其检测
Chap four: Surface roughness and its’ Verification
江苏大学机械工程学院机制系
零件表面粗糙度
工序是工艺过程的基本组成单位。 所谓工 序是指 在一个 工作地 点，对 一个或 一组工 件所连 续完成 的那部 分工艺 过程。 构成一 个工序 的主要 特点是 不改变 加工对 象、设 备和操 作者， 而且工 序的内 容是连 续完成 的。例 如图32-1中[cc 1]的
零件，其工艺过程可以分为以下两个 工序：
工艺路线的拟定是制定工艺过程的总 体布局 ，主要 任务是 选择各 个表面 的加工 方法， 确定各 个表面 的加工 顺序， 以及整 个工艺 过程中 工序数 目的多 少等。
拟定工艺路线的一般原则
1、先加工基准面
零件在加工过程中，作为定位基准的表 面应首 先加工 出来， 以便尽 快为后 续工序 的加工 提供精 基准。 称为“ 基准先 行”。
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六. 练习题
Exercises
练习1： 找出下图中粗糙度代号标注方法上的错误并改正之。
缺少其余“字样”，位置应放到图的右上方 其余 2 5 2 5 粗糙度符号的尖端应与表面接触上
数 字 应 头 向 左
同一表面重复标 注，且字头向下了
1 .6
12.5
12.5
Ra应省略
6 6. 3. 3
深圳大学工程技术学院 胡 琳
三.表面粗糙度符号 SYMBOL OF SURFACE TEXTURE
(1)基 本 代 号 ：
2H
H 60° 60° 用 去 除 表 层 金 属 方 法 获 得用 不 去 除 表 层 金 属 方 法 获 得
一 般 不 单 独 使 用 (车 、 铣 、 钻 、 磨 、 抛 光 、 腐 蚀 )(铸 、 锻 、 冲 压 、 热 轧 、 冷 轧 )
英国某公司图纸
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