Technology & Engineering
Dimensioning
Dimensioning is the process of defining and specifying the measurements and geometric characteristics of an object or part. It involves indicating the size, shape, and location of features on a technical drawing or 3D model using standardized symbols and conventions. Proper dimensioning is crucial for ensuring accurate manufacturing and assembly of components.
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eBook - PDFEngineering Design Graphics
Sketching, Modeling, and Visualization
- James M. Leake, Molly Hathaway Goldstein, Jacob L. Borgerson(Authors)
- 2022(Publication Date)
- Wiley(Publisher)
CHAPTER 1 248 9 CHAPTER ❚ Dimensioning Introduction An engineering drawing, once submitted to pro- duction for manufacture or construction, must include all of the information needed to build the part, assembly, or system. To this end, technical drawings include dimensions and general notes describing the size and location of part features, as well as details related to the construction or manufacture of the part. A dimension is a numerical value used to define the size, location, geometric characteristic, or surface texture of a part or feature. The main goals of Dimensioning (as laid out in ANSI/ ASME Y14.5M, “Dimensioning and Tolerancing for Engineering Drawings”), are the following: 1. Use only the dimensions needed to com- pletely define the part, nothing more. 2. Select and arrange dimensions to support the function and mating relationship of the part. It is important that the dimensioned part not be subject to differing interpretations. 3. In general, do not specify the manufacturing methods to be used in building the part. This is done both to leave options open to manufacturing and to avoid potential legal problems. 4. Arrange the dimensions for optimum read- ability. Dimensions should appear in true profile views and refer to visible object edges. 5. Unless otherwise stated, assume angles to be 90 degrees Units of Measurement Drawings are typically dimensioned using either millimeters or decimal inches. Metric (Système Internationale) drawings normally employ milli- meters specified as whole numbers, as shown in Figure 9-1a. In the English or Imperial system, the preferred units are inches expressed in decimal form, as seen in Figure 9-1b. In some disciplines, Dimensioning AND TOLERANCING 50 50 25 75 (a) Metric (b) English 2.00 3.00 2.00 1.00 Figure 9-1 Metric versus English unit dimensions
eBook - PDFEngineering Design Graphics
Sketching, Modeling, and Visualization
- James M. Leake, Jacob L. Borgerson(Authors)
- 2012(Publication Date)
- Wiley(Publisher)
183 6 C H A P T E R Dimensioning AND TOLERANCING ❚ Dimensioning Introduction An engineering drawing, once submitted to pro- duction for manufacture or construction, must include all of the information needed to build the part, assembly, or system. To this end, technical drawings include dimensions and general notes describing the size and location of part features, as well as details related to the construction or manufacture of the part. A dimension is a numerical value used to define the size, location, geometric characteris- tic, or surface texture of a part or feature. The main goals of Dimensioning (as laid out in ANSI/ ASME Y14.5M, “Dimensioning and Tolerancing for Engineering Drawings”), are the following: 1. Use only the dimensions needed to com- pletely define the part, nothing more. 2. Select and arrange dimensions to support the function and mating relationship of the part. It is important that the dimensioned part not be subject to differing interpretations. 3. In general, do not specify the manufacturing methods to be used in building the part. This is done both to leave options open to manufac- turing and to avoid potential legal problems. 4. Arrange the dimensions for optimum read- ability. Dimensions should appear in true pro- file views and refer to visible object edges. 5. Unless otherwise stated, assume angles to be 90 degrees. Units of Measurement Drawings are typically dimensioned using either millimeters or decimal inches. Metric (Système Internationale) drawings normally employ mil- limeters specified as whole numbers, as shown in Figure 6-1a. In the English or Imperial system, the preferred units are inches expressed in deci- mal form, as seen in Figure 6-1b. In some dis- ciplines, notably architecture and construction, fractional inches are still employed, but deci- mals are preferred because of the easier arith- metic and the greater precision they provide. Drawings in inches are typically specified using two-decimal-place accuracy.
eBook - PDFAutodesk Inventor 2024 and Engineering Graphics
An Integrated Approach
- Randy H. Shih(Author)
- 2023(Publication Date)
- SDC Publications(Publisher)
The dimensions put on the drawing are not necessarily the same ones used to create the drawing but are those required for the proper functioning of the part, as well as those needed to manufacture the design. It is therefore important, prior to Dimensioning the drawing, to study and understand the design’s functional requirements; then consider the manufacturing processes that are to be performed by the pattern-maker, die-maker, machinist, etc., in determining the dimensions that best give the information. In engineering graphics, a detailed drawing is a drawing consisting of the necessary orthographic projections, complete with all the necessary dimensions, notes, and specifications needed to manufacture the design. Considerable experience and judgment are required for accurate size and shape description. Dimensioning a design correctly requires conformance to many rules. For example, detail drawings should contain only those dimensions that are necessary to make the design. Dimensions for the same feature of the design should be given only once in the same drawing. Nothing should be left to chance or guesswork on a drawing. Drawings should be dimensioned to avoid any possibility of questions. Dimensions should be carefully positioned, preferably near the profile of the feature being dimensioned. The designer and the CAD operator should also be as familiar as possible with materials, methods of manufacturing and shop processes. 8-4 Autodesk Inventor and Engineering Graphics Dimensioning Standards and Basic Terminology The first step to learning to dimension is a thorough knowledge of the terminology and elements required for dimensions and notes on engineering drawings. Various industrial standards exist for the different industrial sectors and countries; the appropriate standards must be used for the particular type of drawing that is being produced.
- Dennis Lieu, Sheryl Sorby(Authors)
- 2016(Publication Date)
- Cengage Learning EMEA(Publisher)
12-1 T he majority of engineered parts require the specification of measurements, sizes, and allowable errors of features on the parts. Engi-neers still need to be able to specify part sizes so that everything fits together and functions as intended. This specification must be completed before the parts can be fabricated. Procedures for size specification must be followed to ensure that these specifications can be easily interpreted, checked, and controlled for proper function of the parts. When an engineer is presented with a formal engineering drawing, whether it is a mechanical device or a construction project, that engineer must be able to read all of its contents correctly. Drawings are legal documents and, as such, are required to contain certain information to ensure that the creators and the receivers inter-pret them properly. Guidelines must be followed to ensure that completed drawings are created, updated, and approved in a manner that estab-lishes a line of accountability. D R A W I N G A N N O T A T I O N A N D D E S I G N I M P L E M E N T A T I O N SECTION FOUR CHAPTER 12 Dimensioning 12-2 CHAPTER 13 Tolerancing 13-1 CHAPTER 14 Working Drawings 14-1 Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
- Randy H. Shih(Author)
- 2021(Publication Date)
- SDC Publications(Publisher)
Dimensioning and Notes 7-3 Introduction In engineering graphics, a detailed drawing is a drawing consisting of the necessary orthographic projections, complete with all the necessary dimensions, notes, and specifications needed to manufacture the design. The dimensions put on the drawing are not necessarily the same ones used to create the drawing but are those required for the proper functioning of the part, as well as those needed to manufacture the design. It is therefore important, prior to Dimensioning the drawing, to study and understand the design’s functional requirements; then consider the manufacturing processes that are to be performed by the pattern-maker, die-maker, machinist, etc., in determining the dimensions that best give the information. In engineering graphics, a detailed drawing is a drawing consisting of the necessary orthographic projections, complete with all the necessary dimensions, notes, and specifications needed to manufacture the design. Considerable experience and judgment are required for accurate size and shape description. Dimensioning a design correctly requires conformance to many rules. For example, detail drawings should contain only those dimensions that are necessary to make the design. Dimensions for the same feature of the design should be given only once in the same drawing. Nothing should be left to chance or guesswork on a drawing. Drawings should be dimensioned to avoid any possibility of questions. Dimensions should be carefully positioned, preferably near the profile of the feature being dimensioned. The designer and the CAD operator should also be as familiar as possible with materials, methods of manufacturing and shop processes. 7-4 Principles and Practice Dimensioning Standards and Basic Terminology The first step to learning to dimension is a thorough knowledge of the terminology and elements required for dimensions and notes on engineering drawings.
eBook - PDF- O. Ostrowsky(Author)
- 2019(Publication Date)
- CRC Press(Publisher)
6 Dimensioning An engineering drawing conveys information in two ways: (a) by a pictorial or orthographic view of the object, (b) by instructions in the form of given sizes or dimensions and notes specifying the manufacturing processes and materials. Dimensions can be considered to be of two types: (i) those which define the size and shape of an object or feature -called size dimensions; (ii) those which specify the relative positions of various features -called location dimensions. In addition, dimensions can be put into three groups relative to the function of a product: functional dimensions, non-functional dimensions, and auxiliary dimensions. 6.1 Functional dimensions These dimensions directly affect the function or working of a pre.duct and may be of the size or location types. Functional dimensions should be based on the function of the component and they can also show the method of locating the component in its appropriate assembly, thus ensuring its correct working within the whole product. A datum is a reference line on the drawing from which a component is dimensioned . In practice, a datum is any functional surface or axis used for manufacture, inspection, location, or assembly purposes. To ensure the required accuracy of measurement, the datum surfaces are machined to the required degree of finish. The main function of the components in the assembly shown in Fig. 6. l is to support a shaft. Hence the functional location dimension, Fi. is between the hole centre and the datum mating face. The fixing holes must be positioned in relation to the shaft and the shoulder on the mating face of the table. The functional dimension Fi is used for this purpose. The same dimension Fi will apply to the bracket and the table. Also, the centre lines of the holes must be positioned relative to the vertical datum using the functional dimensions FJ and F4. Functional dimensions are used for production and inspection purposes.
eBook - PDF- Robert J. Hocken, Paulo H. Pereira, Robert J. Hocken, Paulo H. Pereira(Authors)
- 2016(Publication Date)
- CRC Press(Publisher)
41 3 Specification of Design Intent Introduction to Dimensioning and Tolerancing Edward Morse For.the.purposes.of.this.chapter,.it.will.be.assumed.that.a.designer.has.thought.care-fully. about. a. part. and. how. it. interacts. with. the. other. parts. in. an. assembly . . The. designer. has. decided. not. only. on. the. optimal. material,. surface. characteristics,. and.dimensions.of.the.part.but.also.on.the.allowable.variations.in.these.quantities . . From. a. design. standpoint,. this. complete. set. of. information. captures. the. intent. of. the.designer,.or.the. design intent . .In.this.chapter,.the.geometric.information.(size,. shape,.form,.and.orientation.of.part.features).will.be.inspected.using.the.coordinate. measuring.machine.(CMM) . CONTENTS 3.1 . Geometric.Tolerancing. ................................................................................... 43 3.1.1 . Principle.Elements.of.Geometric.Tolerancing. .................................... 43 3.1.1.1 . Zones. .................................................................................... 44 3.1.1.2 . Datums. ................................................................................. 44 3.1.1.3 . Basic.Dimensions. ................................................................. 45 3.1.2 . Types.of.Tolerances. ............................................................................ 46 3.1.2.1 . Form. ..................................................................................... 46 3.1.2.2 . Orientation. ........................................................................... 47 3.1.2.3 . Profile. ................................................................................... 47 3.1.2.4 . Runout. .................................................................................. 48 3.1.2.5 . Size. .......................................................................................
eBook - PDFTechnical Drawing 101 with AutoCAD 2023
A Multidisciplinary Guide to Drafting Theory and Practice
- Ashleigh Congdon-Fuller, Douglas Smith, Antonio Ramirez(Authors)
- 2022(Publication Date)
- SDC Publications(Publisher)
When a checker initials this box, it indicates that the drawing has passed the checker’s review. It also means that the drafter is no longer the only one responsible for the accuracy of the drawing. 5.6 DESIGN BASICS: HOW DESIGNERS CALCULATE DIMENSIONS Mechanical engineers and designers are responsible for calculating the dimensions of an object. They determine the dimensional values by carefully considering the form, fit, and function of the object they are designing. For example, the material from which the part is to be manufactured, how the object fits with other parts in an assembly, and the role it plays in the overall design are all factors that may affect the size and location of the features of a part. Sometimes, the dimensions define the aesthetic rather than the functional qualities of the finished object. The aesthetic qualities of an object refer more to the object’s appearance than to its function. Because the designer’s dimensions are carefully calculated, it is very important that they are faithfully reproduced by the drafter during the preparation of an engineering drawing. To appreciate how crucial it is that the designer’s dimensions be accurately portrayed in a mechanical drawing, drafters must have an understanding of a very important concept of mechanical design: tolerances. An effective strategy for checking the sketch against the drawing is to use a yellow marker to highlight the dimensions on the sketch and the drawing, one by one, until all are accounted for. JOB SKILL Dimensioning MECHANICAL DRAWINGS 259 5.7 TOLERANCES Manufacturing a machine part to an extreme degree of precision is difficult and expensive; therefore, designers must decide how much the size and location of a part’s features can deviate from the dimensions specified on the drawing and still perform their design function. This allowable variation in the location, or size, of a feature is called the tolerance.
eBook - PDF- Michael J. Rider Ph.D.(Author)
- 2021(Publication Date)
- SDC Publications(Publisher)
198 CHAPTER 7 Dimensioning the parts fit together properly. If a question came up, the worker would consult the designer who was always nearby. Under these manufacturing conditions, it was not necessary for drawings to carry detailed dimensions or notes. The modern methods of size description came into existence with the need for interchangeable parts. Detailed drawings must be dimensioned so that a worker can produce mating parts that can be assembled in a separate factory or when used as replacement parts by the customer. The need for precision manufacturing and the controlling of sizes for interchangeability shifted from the machinist to the designing engineer. The worker no longer used his judgment in engineering matters, but rather he executed the instructions given on the detailed drawings. Thus, it was necessary for design engineers to become familiar with materials and the processes of the shop. The drawings must show the part in its completed form and contain all information necessary to make it. Therefore, when Dimensioning a detailed drawing, the engineer must keep in mind the finished part, the shop processes required, and the design intent of the part. Dimensions need to be given that are required by the worker when making the part. There is no reason to provide dimensions to points or surfaces that are not accessible to the worker. Dimensions must not be duplicated on a drawing. Only dimensions needed to produce and inspect the part, as intended by the design engineer, should be shown. The beginner often makes the mistake of giving the dimensions he/she used to make the computer-generated part model or the drawing. These are not necessarily the dimensions required by the shop. Drawings must be made to scale with the scale listed in the title block. Learn to Dimension Properly Dimensions are given in the form of linear distances, angles, and notes.
eBook - PDF- Michael J. Rider Ph.D.(Author)
- 2024(Publication Date)
- SDC Publications(Publisher)
The need for precision manufacturing and the controlling of sizes for interchangeability shifted from the machinist to the designing engineer. The worker no longer used his judgment in engineering matters but rather executed the instructions given on the detailed drawings. Thus, design engineers needed to become familiar with the materials and the processes of the shop. The drawings must show the part in its completed form and contain all information necessary to make it. Therefore, when Dimensioning a detailed drawing, the engineer must keep in mind the finished part, the shop processes required, and the design intent of the part. Dimensions need to be given that are required by the worker when making the part. There is no reason to provide dimensions to points or surfaces that are not accessible to the worker. Dimensions must not be duplicated on a drawing. Only the dimensions needed to produce and inspect the part, as intended by the design engineer, should be shown. The beginner often makes the mistake of giving the dimensions he/she used to make the computer- generated part model or the drawing. These are not necessarily the dimensions required by the shop and should not be on the engineering drawing. Drawings must be made to scale with the scale listed in the title block. Dimensioning Designing with SOLIDWORKS 2024 6-2 Learn to Dimension Properly Dimensions are given in the form of linear distances, angles, and notes. The engineer must learn the skills of Dimensioning; that is the type of lines to use, the spacing between dimensions, proper note creation, etc. A sample detailed part drawing is shown below without the border and title block. The beginner must learn the rules for placing dimensions on a detailed drawing. The suggestions to follow provide a logical arrangement for maximum legibility. The part’s function is considered first; the shop processes second.
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