ASME Y14.5-2018 is the authoritative guideline for geometric dimensioning and tolerancing (GD&T). It establishes symbols, rules, definitions, and requirements for use on engineering drawings and 3D models

ASME Y14.5-2018 was published on February 11, 2019

ASME Y14.5-2018 is more comprehensive, with 328 pages compared to the 214 pages of the 2009 version

The standard covers 2D drawings and 3D model-based definitions, includes rules for GD&T, and addresses form, orientation, location, and runout tolerances

The standard is organized into nine parts, with details of the geometrical characteristics in parts five through nine

Key updates include new symbols for tolerance zones and datum reference frames, guidance on GD&T in 3D CAD models, expanded definitions, and new requirements for digital product definition

Yes, two new symbols were added: the "From-To" symbol and the "dynamic profile tolerance zone modifier

This standard is crucial for mechanical engineers, design engineers, manufacturing engineers, quality control professionals, and CAD/CAM specialists

It aims to improve quality, lower costs, and shorten deliveries in mechanical part design and manufacturing by providing uniformity in drawing specifications and interpretation

The standard includes expanded coverage of 3D model-based definition (MBD) and provides guidance on the use of GD&T in 3D CAD models

Runout definitions were overhauled to move away from inspection-based definitions towards more theoretical tolerance boundaries

Companies may choose to fully adopt the updated standard or continue using previous versions, depending on their specific needs and practices

Yes, ASME Y14.5-2018 is designed to be compatible with other international standards, such as ISO standards for pipeline integrity management

Future updates may focus on further refining definitions, incorporating new technologies, and addressing evolving industry needs

ASME Y14.5-2018 provides detailed guidelines for establishing and using datum reference frames, including:

• Primary, secondary, and tertiary datum features
• Datum feature simulators
• Datum targets
• Composite datum reference frames

The 2018 edition includes several updates to profile tolerancing:

• Clarified rules for unilateral and bilateral profile tolerances
• New symbols for specifying non-uniform profile tolerances
• Expanded guidance on applying profile tolerances to 3D surfaces

The standard provides comprehensive coverage of position tolerances, including:

• Basic dimensions and their relationship to position tolerances
• Application of material condition modifiers (MMC, LMC, RFS)
• Composite position tolerances
• Position tolerances applied to patterns of features

ASME Y14.5-2018 expands on MBD concepts, covering:

• Annotation of 3D CAD models with GD&T information
• Semantic PMI (Product and Manufacturing Information)
• Associativity between annotations and model geometry
• Best practices for creating and interpreting 3D annotated models

The standard provides guidance on:

• Equivalent representations of GD&T in 2D and 3D environments
• Maintaining consistency between 2D drawings and 3D models
• Considerations for mixed 2D/3D documentation environments

Key updates include:

• Refined definitions of measurement principles
• Guidance on using coordinate measuring machines (CMMs)
• Considerations for statistical tolerancing and process capability
• Alignment of inspection methods with design intent

The standard provides:

• Guidelines for applying statistical tolerancing concepts
• Symbols and notations for statistical tolerance specifications
• Relationships between statistical tolerances and process capability indices

While ASME Y14.5-2018 and ISO GPS standards have some differences, the 2018 edition includes:

• Increased harmonization of terminology and concepts
• Cross-references to relevant ISO standards
• Guidance on interpreting drawings created under different systems

Some notable differences include:

• Symbology for certain tolerances and modifiers
• Treatment of datum reference frames
• Approach to profile tolerancing
• Terminology for some GD&T concepts

The standard provides detailed guidance on:

• Composite position tolerances
• Composite profile tolerances
• Application of composite tolerances to patterns

ASME Y14.5-2018 includes:

• Symbols and notations for specifying free-state conditions
• Guidelines for applying tolerances to parts in a restrained state
• Considerations for measuring and inspecting flexible parts

The standard influences CAD/CAM software development by:

• Defining requirements for GD&T representation in 3D models
• Providing guidelines for semantic PMI implementation
• Influencing tolerance analysis and simulation capabilities
• Shaping export formats for downstream manufacturing processes

Key considerations include:

• Ensuring compatibility with legacy data and drawings
• Managing the transition to 3D annotated models
• Implementing approval workflows for GD&T specifications
• Integrating GD&T data with manufacturing and quality systems

Resources include:

• Official ASME training courses and workshops
• Third-party training providers specializing in GD&T
• Online learning platforms offering ASME Y14.5-2018 courses
• Textbooks and study guides aligned with the 2018 edition

Yes, several organizations offer certifications, including:

• ASME's Geometric Dimensioning and Tolerancing Professional (GDTP) certification
• American Society for Quality (ASQ) Certified GD&T Professional
• Various industry-specific GD&T certifications aligned with ASME Y14.5-2018