and Tolerancing is a system for defining and communicating engineering design
with tolerances. Using symbols on engineering drawings and computer-generated
three-dimensional solid models it explicitly describes the geometry of the part
and its allowable variation, explaining, the manufacturing staff and machines,
the degree of accuracy and precision needed. GD&T is defining the
theoretically perfect geometry of parts and assemblies, There are several
standards worldwide t0 describe symbols and define the rules used in GD&T.
One such standard being American Society of Mechanical Engineers (ASME)
Y14.5-2009. The uniqueness in Y14.5 standard is that it provides a fairly
complete set of standards for GD&T in a single document.
Importance of GD&T
Tolerance analysis and GD&T of designs bring robustness and accuracy to product designs, significantly improving product quality while drastically reducing production costs. Industries that make use of mechanical designing, like, Aerospace & Defense, Heavy Industry, Automotive, HVAC, Consumer Products, Medical Devices, Electronics & Power, Safety & Security Systems, etc, GD&T is an integral part of their operation. The production uses the language to interpret the design intent, and inspection looks to the language to determine the setup. By providing uniformity in drawing specifications and interpretation, GD&T reduces controversy, guesswork, and assumptions throughout the manufacturing and inspection process, and hence plays a contributing factor to many industries.
GD&T is part of the designing process which is an effective tool to
● communicate design features between the designer and the manufacturer.
● It simplifies inspection
● forces the designer to totally consider function, manufacturing process, and inspection methods.
It is the most important tool for a designer to learn and a manufacturer to understand. This course offers all the information needed for a designer to initiate his career as a mechanical designer.