Standard covers geometric dimensioning and tolerancing

Geometric dimensioning and tolerancing (GD&T) is a symbolic language used by mechanical engineers to efficiently and accurately convey geometry requirements for features on parts and assemblies. Used in automotive, aerospace, electronic, and other manufacturing industries, GD&T communicates design intent in order to assure that the allowable part and assembly geometry defined on technical drawings (blueprints) leads to parts that have the desired form, fit, function and interchangeability when manufactured. By providing uniformity in drawing specifications and interpretation, GD&T reduces guesswork throughout the manufacturing process and helps to save time, improve quality, and lower costs.

The American Society of Mechanical Engineers (ASME) recently published ASME Y14.5-2009, Dimensioning and Tolerancing, a revised ANS that provides useful clarifications to the 1994 edition. ASME Y14.5-2009 includes changes that address the concept of feature design, datum references and degrees of freedom, surface boundaries and axis methods of interpretation, profile tolerances and symbology, and modifiers’ tools. The document’s content has been restructured for better readability, helping designers to fully and reliably express the desired functions of machine parts.

ASME, an ANSI organizational member and accredited standards developer, is a not-for-profit professional organization promoting the art, science, and practice of mechanical and multidisciplinary engineering and allied sciences. ASME develops codes and standards that enhance public safety, and enables learning and technical exchange opportunities benefiting the global engineering and technology community.