Technical Drawing for Product Design
Mastering ISO GPS and ASME GD&T
- 2024
- Book
- Author
- Stefano Tornincasa
- Book Series
- Springer Tracts in Mechanical Engineering
- Publisher
- Springer International Publishing
About this book
This book is intended for students, academics, designers, process engineers and CMM operators, and presents the ISO GPS and the ASME GD&T rules and concepts. The Geometric Product Specification (GPS) and Geometrical Dimensioning and Tolerancing (GD&T) languages are in fact the most powerful tools available to link the perfect geometrical world of models and drawings to the imperfect world of manufactured parts and assemblies. The topics include a complete description of all the ISO GPS terminology, datum systems, MMR and LMR requirements, inspection, and gauging principles. Moreover, the differences between ISO GPS and the American ASME Y14.5 standards are shown as a guide and reference to help in the interpretation of drawings of the most common dimensioning and tolerancing specifications. The book may be used for engineering courses and for professional grade programmes, and it has been designed to cover the fundamental geometric tolerancing applications as well as the more advanced ones. Academics and professionals alike will find it to be an excellent teaching and research tool, as well as an easy-to-use guide.
This 2nd, revised edition includes several improved features:
- It highlights the tools provided in the recently published ISO GPS standards, such as ISO 22081-2021 and ISO 2692-2021.
- New concepts and rules in accordance with the latest revision to the GD&T standard, ASME Y14.5.1-2019, Mathematical Definition of Dimensioning and Tolerancing Principles.
- Most of the drawings have been redrawn and updated even further to the new standards.
- Changes have been made to the text and illustrations to improve readability and clarify the content
Additional contents and examples have been included.
- The chapters dedicated to profile tolerance and tolerances (ISO 14405) have been extended and rewritten.
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Table of Contents
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Frontmatter
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Chapter 1. Introducing GD&T and GPS
Stefano TornincasaThis chapter delves into the significance of Geometric Dimensioning and Tolerancing (GD&T) and Geometrical Product Specification (GPS) in modern manufacturing. It begins by explaining the fundamental principles of GD&T and GPS, emphasizing their role in defining allowable limits of imperfection in as-produced parts. The text then critically examines the shortcomings of traditional coordinate tolerancing, such as the neglect of form errors and the potential for ambiguous measurements. It highlights the necessity of evaluating form and dimensions in the context of functional requirements, especially as the complexity of designed objects increases. The chapter also introduces the functional dimensioning method as a solution to these challenges, enabling precise and unambiguous communication of part specifications. Additionally, it provides historical context on the development of GD&T and GPS, underscoring their evolution from wartime necessities to essential tools in contemporary manufacturing. The chapter concludes by emphasizing the importance of clear and rigorous technical product documentation to ensure unambiguous interpretation and reduce production and inspection costs.AI Generated
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AbstractThe technical product documentation that is currently drawn up in many companies is unfortunately still ambiguous and contains many errors, such as erroneous datums, imprecise or missing distances, as well as incongruent and difficult to check tolerances. For about 150 years, a tolerancing approach called “coordinate tolerancing” was the predominant tolerancing system used on engineering drawings. This methodology in fact no longer results to be the most suitable for the requirements of the modern global productive realty, in which companies, for both strategic and market reasons, frequently resort to suppliers and producers located in different countries, and it is therefore necessary to make use of communication means in which the transfer of information is both univocal and rigorous. GD&T or GPS is a symbolic language that is used to specify the limits of imperfection that can be tolerated in order to guarantee a correct assembly, as well as the univocal and repeatable functionality and control of the parts that have to be produced. -
Chapter 2. The Geometrical Product Specification (GPS) Language
Stefano TornincasaThe chapter delves into the Geometrical Product Specification (GPS) Language, emphasising its role in enhancing the precision and clarity of technical product information. It discusses the evolution of GPS standards, such as ISO 17450 and ISO 14660, and their impact on the specification and verification of workpiece geometries. The text explores the classification of geometrical tolerances and their application in various industries, highlighting the importance of accurate technical communication in a globalised production environment. Additionally, it provides insights into the use of GPS in improving co-design and outsourcing processes, making it a valuable resource for professionals seeking to enhance their understanding of modern technical documentation practices.AI Generated
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AbstractThe main concepts proposed in this chapter have the aim of expressing the fundamental rules on which the geometrical specification of workpieces can be based through a global approach that includes all the geometrical tools needed for GPS. Indeed, in an increased globalisation market environment, the exchange of technical product information and the need to unambiguously express the geometry of mechanical workpieces, are of great importance. The symbols, terms, and rules of the GPS language that are given in the ISO 17450, ISO 1101 and ISO 14660 standards are presented in this chapter through tools and concepts that allow an engineer to perfectly specify the imperfect geometry of a component, and to understand the impact of the drawing specifications on inspection. -
Chapter 3. Dimensioning with Geometrical Tolerances
Stefano TornincasaThe chapter 'Dimensioning with Geometrical Tolerances' explores the transition from traditional 2D coordinate tolerancing to the geometrical tolerance method. It delves into the principles of setting up Cartesian reference systems and defining tolerance zones for workpiece features. The advantages of this method include reduced tolerance accumulation, unambiguous control processes, and increased tolerance zones, leading to improved product functionality and performance. The chapter also discusses the application of these methods in 3D CAD models and the importance of adopting advanced specification and verification methodologies based on ISO and ASME standards. By doing so, it aims to enhance communication between design, production, and quality control entities, ultimately transforming the control process into a reliable and scientific endeavor.AI Generated
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AbstractThe advantages of the geometric specification of a product are here illustrated by converting a traditional 2D coordinate tolerancing drawing using the geometrical tolerance method. The new language of symbols permits the functional requirements of the products to be fully expressed in technical documentation. Moreover the dimensioning of a workpiece according to the geometrical tolerance method can reduce the ambiguity in the indications and in the interpretation of the dimensional and geometrical requirements of the products in order to achieve not only unambiguous communication between the design, production and quality control entities, but also with the clients and suppliers of the outsourced processes. -
Chapter 4. The GPS and GD&T Language
Stefano TornincasaThe chapter delves into the historical evolution of GPS and GD&T standards, focusing on the ISO and ASME frameworks. It discusses the increasing importance of dynamic interaction models between clients and suppliers, which has put pressure on traditional technical communication methodologies. The chapter introduces the GPS Matrix Model and the key principles of the ISO 8015 standard, including the Independency Principle and the Default Principle. It also compares the main differences between ISO GPS and ASME GD&T standards, highlighting the distinct approaches to form and dimension interdependence, specification and verification principles, and the use of general tolerances. The chapter concludes by emphasizing the importance of clear and unambiguous technical documentation to ensure functionality, reliability, verifiability, and interchangeability in mechanical subcontracting.AI Generated
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AbstractThis chapter is focused on the main differences between the ISO and ASME standards in the geometrical specification domain of the industrial products, and it starts with details on the historical evolution of the two standards. The main principles of the ISO GPS and ASME GD&T standards, such as the principle of independence and the envelope requirement, are illustrated. Designers are recommended to always indicate the reference standard in the technical drawings of companies, as the interpretation of drawing specifications and the relative inspection may lead to two different results. Finally, the main novelties of the new ASME Y14.5:2018 standard and the new ISO 22081 standard on general tolerances are shown. -
Chapter 5. Interdependence Between Dimensions and Geometry
Stefano TornincasaThis chapter delves into the complex interplay between dimensions and geometry in engineering, particularly focusing on exceptions defined by the ISO 2692 standard. It introduces the Maximum Material Requirement (MMR) and Least Material Requirement (LMR) principles, explaining how they allow for the combination of independent requirements and the definition of virtual conditions. The text explores the practical applications of these requirements, including their impact on assembly, mating conditions, and manufacturing costs. It also discusses the reciprocity requirement (RPR) and the direct indication of virtual size, providing a comprehensive overview of advanced GD&T concepts. Throughout the chapter, real-world examples and technical drawings are used to illustrate these principles, making it an invaluable resource for professionals seeking to optimize their manufacturing processes.AI Generated
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AbstractIn ISO GPS terminology, the maximum material requirement, (MMR) and least material requirement (LMR) represent two of the fundamental rules on which geometrical dimensioning with tolerances is based, and which are the subject of the ISO 2692 standard. The designer, when establishing a maximum or least material requirement, defines a geometrical feature of the same type and of perfect form, which limits the real feature on the outside of or inside the material. MMR is used to control the assemblability of a workpiece while LMR is used to control a minimum distance or a minimum wall thickness. This chapter also introduces the Reciprocity requirement (RPR) and the “zero tolerance” concepts and offers practical examples to guide a designer in his/her choice of the correct requirement from the geometrical tolerance specifications. -
Chapter 6. Datums and Datum Systems
Stefano TornincasaThe chapter delves into the significance of datum systems in technical drawings, emphasizing their role in defining tolerance zones and ensuring the repeatability of measurements. It explains the distinction between datum features and datums, the importance of selecting datums based on functional requirements, and the common misconceptions surrounding their use. The text also covers the establishment of datum reference frames, the association of datums with ideal features, and the use of various modifiers to specify the size and orientation of datums. Additionally, it discusses the differences between ISO and ASME standards for datum systems and provides practical examples to illustrate the application of datum systems in engineering drawings.AI Generated
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AbstractA datum system has the purpose of defining a set of two or more ideal features established in a specific order (for example, a system made up of a triad of mutually orthogonal planes) that allows not only the tolerance zones to be orientated and located, but also their origin to be defined for the measurement, and the workpiece to be blocked during the control. When it is not desirable to use a complete integral feature to establish a datum feature, it is possible to indicate portions of the single feature (areas, lines or points) and their dimensions and locations using datum targets. This chapter illustrates the main differences between the ISO 5459 and ASME standards for the specification of datums and highlight some theoretical and mathematical concepts. This section also provides simple rules to follow whenever choosing functional datums to ensure the part will function as intended, with the least possible amount of variation. -
Chapter 7. Form Tolerances
Stefano TornincasaThe chapter begins by introducing form tolerances, which are used to establish variation limits for surfaces and features on engineering drawings. It covers four types of form tolerances: straightness, flatness, roundness, and cylindricity. Straightness controls the deviation of linear features from a straight line, with specific rules for application and interpretation. Flatness ensures all points on a surface belong to the same plane, with methods to control and measure this tolerance. Roundness and cylindricity deal with the circular and cylindrical properties of surfaces, respectively, with detailed procedures for evaluation and application. The chapter also discusses the use of various standards, such as ASME and ISO, to ensure accurate and consistent tolerance application. It highlights the importance of understanding and applying these tolerances to maintain high-quality manufacturing standards.AI Generated
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AbstractIt is possible to control four form tolerance types: straightness, flatness, roundness and cylindricity. The chapter covers all the concepts necessary to define specification operators (according to ISO 17450-2) and some procedures to establish the reference elements in order to define the deviation errors. Some terms related to form parameters are described such as peak-to-valley, peak-to-reference and reference-to-valley deviations. The ASME standards use the envelope requirements or Rule #1, according to which form tolerances are contained within the dimensional ones, and these tolerances are therefore only used with the purpose of limiting the error when the workpiece is produced with dimensions close to the least material condition. -
Chapter 8. Orientation Tolerances
Stefano TornincasaThis chapter delves into the intricacies of orientation tolerances, focusing on parallelism, perpendicularity, and angularity. It explains how these tolerances control the orientation of features with respect to datums, using detailed examples and illustrations. The text explores the application of these tolerances to median lines and surfaces, and discusses the differences between ISO and ASME standards in defining and interpreting orientation tolerances. Additionally, it highlights the importance of theoretically exact dimensions and the use of modifiers to achieve specific control requirements. The chapter is particularly valuable for its practical approach, providing clear guidelines and comparisons that help professionals understand and apply orientation tolerances effectively in their work.AI Generated
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AbstractOrientation tolerances (parallelism, perpendicularity and angularity) are used to control the orientation of a feature (surface or feature of size) with respect to one or more datums. When the orientation tolerances are applied to a feature of size and an MMR or LMR is added, the control of the orientation deviation no longer refers to the median line, but to the entire extracted feature (MMVC boundary), and it should not violate the MMVC virtual condition. The ISO and ASME standards use two different approaches to control the orientation of a feature of size: in order to orient a feature of size, the ISO standards define the concept of extracted median line or median surface. Instead, in the ASME standards, the axis or median plane is used to control the orientation of a feature of size. -
Chapter 9. Location Tolerances
Stefano TornincasaLocation tolerances establish the permissible variations in the position of a feature relative to datums. This chapter delves into various types of location tolerances, such as those for axes, median planes, and surfaces, and discusses methods to control these tolerances, including position, profile, and run-out controls. It also covers the use of modifiers like MMR and LMR, and provides formulas for calculating tolerances. Additionally, the chapter explores pattern location and composite position tolerances, offering practical examples and illustrations to clarify complex concepts. The text emphasizes the importance of geometrical tolerances in preventing tolerance accumulation and ensuring functional design, making it a valuable resource for professionals in the field of mechanical design and quality control.AI Generated
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AbstractThis chapter describes how to use location tolerances to specify an allowable location error. The location tolerances that should be used, in function of the feature of the workpiece that has to be located, are in particular presented. The effects of the material condition requirement and the correct choice of the modifiers for position tolerances (axis and surface interpretation) are illustrated. Particular emphasis is given to the location of the patterns, as introduced with the new rules of the ISO 5458:2018 standard (multiple indicator pattern specification and simultaneous requirement). When geometrical position tolerances are applied, the value of the tolerance is calculated from the mating conditions (fixed and floating fastener conditions). The ASME standards specify, without any shadow of doubt, that the position tolerance symbol should only be utilised for a “feature of size”, while the ISO standards allow it to be used to position a planar surface. The ISO standards are defined as “CMM Friendly”, that is, the preferred control system is the coordinate measurement machine, while the ASME standards are based on functional gauges that represent a physical representation of the tolerance zone. A special functional application of location tolerances is to control concentricity and symmetry. These controls have been removed from the new ASME standard. -
Chapter 10. Profile Tolerances
Stefano TornincasaThe chapter on profile tolerances delves into the versatile and powerful tool of geometrical tolerance on profiles, which controls not just form but also size, orientation, position, and form of features. It discusses the use of profile tolerances on both complex and simple profiles, highlighting their widespread adoption in modern engineering. The outline of a feature as a profile and its control are defined, with methods for indicating profile tolerances on lines and surfaces. The chapter also explores the use of profile tolerancing as an alternative to classical coordinate dimensioning, showcasing its advantages in controlling surface location, parallelism, flatness error, and size. Rules and examples for profile tolerancing are provided, including the use of dynamic profiles and offset tolerance zones. The differences between ISO and ASME standards in defining profile tolerance zones are explained, along with new symbols and modifiers introduced in recent standards. The chapter concludes with a discussion on profile measurement methods and the practical application of profile tolerancing in engineering drawings.AI Generated
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AbstractA geometrical tolerance on a profile is one of the most versatile and powerful instruments that can be used for functional dimensioning, and is the tolerance most frequently used by designers. A profile may in fact be used to control the size, form, orientation and location of a feature. Because of the flexibility in the level of control that can be achieved with the profile tolerance, this control may be used to substitute the classical coordinate dimensioning method. The present chapter covers the ISO rules on profile tolerances in order to appropriately specify the control of a profile with a combination of the SZ, CZ, UF symbols and the bidirectional and unidirectional zones that are specified with profile tolerances. A composite profile tolerance is used in the ASME standards when the design applications require stricter tolerances on the form than is needed for the orientation or location of the same feature. The new ASME symbols, that is, From-To and dynamic profile, are presented. -
Chapter 11. Run-Out Tolerances
Stefano TornincasaRun-out tolerances are crucial controls that define the permissible coaxiality, orientation, and form deviations of surface elements relative to a datum axis. These tolerances can be categorized into circular run-out and total run-out, each with distinct symbols and applications. Circular run-out controls individual circular features independently, while total run-out ensures all surface points fall within a common 3D tolerance zone. Inspection methods include dial indicators, coordinate measuring machines, and roundness measuring instruments. The chapter also discusses the application of run-out tolerances in the ASME Y14.5 standards and their importance in preventing critical vibrations and unwanted effects in rotating components. The detailed explanation of these tolerances and their inspection methods makes this chapter an invaluable resource for professionals seeking to ensure the precision and reliability of their mechanical components.AI Generated
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AbstractA run-out error is the surface variation that occurs relative to a rotation axis. There are two types of run-out controls: circular run-out (2D) and total run-out (3D). Run-out tolerances are composite controls that define the requirements for the permissible coaxiality, orientation and form deviations of a surface element in relation to a datum axis. The application of the run-out control to an assembly and its combination with the tangent plane symbol, are illustrated in this chapter as main novelties of the new ASME Y14.5:2018 standard. -
Chapter 12. Geometrical Specification for Non-rigid Parts
Stefano TornincasaThe chapter delves into the geometrical specification of non-rigid parts, which deform under their own weight or assembly constraints. It emphasizes the importance of distinguishing between free state and restrained conditions for accurate measurement and assembly. The ISO 10579-NR standard is introduced, mandating the identification of non-rigid parts on drawings and specifying the necessary clamping forces. The ASME Y14.5:2018 standard is also discussed, providing guidelines for applying tolerances under restrained conditions to simulate functional requirements. Practical examples, such as metal sheeting structures, illustrate the significance of proper restraint to ensure part functionality. The chapter concludes with a detailed control procedure, emphasizing the necessity of congruent forces and constraints to verify non-rigid parts effectively.AI Generated
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AbstractIn the absence of other indications, all the specified dimensions and tolerances are applied and controlled without the action of any force, except gravity, but components such as thin metal and flexible parts, rubber gaskets, and flexible parts in general, can deform or bend, even as just a result of their weight. These components should be inspected under a restrained condition in order to simulate their shape in the installed condition. The restraint or force on the non-rigid parts is usually applied in such a manner as to resemble or approximate the functional or mating requirements. According to the ISO standards, the non-rigid parts should be identified on a drawing by means of “ISO 10579-NR” (Non Rigid) obligatory indications within or near the title block; such a note indicates that the part is not considered rigid and it indicates the clamping forces or other requirements necessary to simulate the assembly conditions. In order to invoke a restrained condition in the ASME standards, a general note, or a local note, should be specified or referenced on the drawing to define the restraint requirements. When a general note invokes a restrained condition, all the dimensions and tolerances apply in the restrained condition, unless they are overridden by a “free state” Ⓕ symbol. -
Chapter 13. Linear Sizes
Stefano TornincasaThe chapter delves into the historical use of traditional metrological instruments for size verification and highlights the limitations of these methods. It introduces the ISO 14405-1:2016 standards, which offer a rich set of new size specification modifiers. These modifiers enable more precise and functional size tolerancing, addressing ambiguities in traditional methods. The chapter also compares these standards with ASME specifications, emphasizing the benefits of the ISO approach in terms of clarity and functionality. Practical examples and drawing indications are provided to illustrate the application of these new standards in real-world scenarios, making the chapter a valuable resource for professionals seeking to enhance their understanding of modern size tolerance specifications.AI Generated
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AbstractIn the past, the verification of the local size of workpieces was carried out using traditional metrological instruments, such as callipers and micrometres, or using hard gauges to check for conformance with the global size tolerances. Today, in order to remove any ambiguities that existed in the traditional size tolerance specifications, it is necessary to both exploit the benefits of CMMs and other coordinate measuring systems that collect several points from the surface of a feature and, at the same time, to expand the concept of size tolerancing in order to communicate the function of a part more clearly. The specification operators defined in the ISO 14405 standards provide mechanisms that can be used to expand the domain of size specifications by means of a rich, new set of size modifiers, which provide new capabilities that can be used to address the requirements that arise from many industrial applications. -
Backmatter
- Title
- Technical Drawing for Product Design
- Author
-
Stefano Tornincasa
- Copyright Year
- 2024
- Publisher
- Springer International Publishing
- Electronic ISBN
- 978-3-031-51187-5
- Print ISBN
- 978-3-031-51186-8
- DOI
- https://doi.org/10.1007/978-3-031-51187-5
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