GD&T: An International Language

GD&T: An Exact Language

GD&T Provides Uniformity

GD&T stands for Geometric Dimensioning and Tolerancing, as defined by ASME Y14.5M-1994. 

GD&T: An International Language Geometric dimensioning and tolerancing is an international language used on drawings to accurately describe a part. The language consists of a well-defined set of symbols, rules, definitions, and conventions that can be used to describe the size, form, orientation, and location tolerances of part features. 

GD&T: An Exact Language Geometric tolerancing is an exact language that enables designers to “say what they mean” on a drawing, thus improving product designs. Production uses the language to interpret the design intent, and inspection looks to the language to determine set up. 

GD&T Provides Uniformity By providing uniformity in drawing specifications and interpretation, GD&T reduces controversy, guesswork, and assumptions throughout the manufacturing and inspection process.

(Based on ASME Y14.5M-1994)

Provide Participants with Fundamental concepts of GDnT

Enable Participants to express, understand and interpret drawing requirements using GDnT to ANSI / ASME Y14.5M Stdandards.

(Based on ASME Y14.5M-1994)

ASME, American Society of Mechanical Engineers.Founded in 1880 by Alexander Lyman Holley, Henry Rossiter Worthington, John Edison Sweet and Matthias N. Forneyin response to numerous steam boiler pressure vessel failures. ASME is an engineering society focused on mechanical engineering in North America, is thus a standards organization, a research and development organization, a provider of training and education, and a nonprofit organization.

- A document that communicates a precise description of a part.- This description consists of pictures, words, numbers, and symbols.

Day 1 The Definitions Datums

Datum feature system (planar datum) Datum Feature Simulator, Datum targets

Dimension Basic and Reference, Using Basic Dimension

Envelop, actual mating Feature

Control frame, axis Of, Center of Plane, SizeFIM, MMC, LMC,RFS Conditions

Size Actual, Nominal & Virtual Tolerance of Position Controls

Bilateral, Geometric, Unilateral, of positionTrue Geometric Counterpart

(Based on ASME Y14.5M-1994)

Day 2 Fundamental Rules Dimensioning & Tolerancing

Selection & arrangement to suit Function and mating relationship

Rule #1 and Rule #2 Basic dimensions, virtual condition, bonus tolerance

Position Controls

Concentricity, Symmetry

Profile ControlsProfile tolerancing Profile of a surface Profile of a line

Workshop Drawing Interpretation Presentation Q & A Discussion

Closing comments

The definitions

Datum Feature Simulator - The inspection equipment (or gage surfaces) used to establish a datum.

Datum Reference Frame - A set of three mutually perpendicular datum planes.

Datum Shift - The allowable movement, or looseness, between the part datum feature and the gage.

Datum System - A set of symbols and rules that communicate to the drawing user how dimensional measurements are to be made.

Datum - A theoretically exact plane, point or axis from which a dimensional measurement is made.

Datum Feature - A part feature that contacts a datum. 

Datum Target - A symbol that describes the shape, size, and location of gage elements that are used to establish datum planes or axes.

Basic Dimension - A numerical value used to describe the theoretically exact size, true profile, orientation, or location of a feature or datum target.

Between Symbol - A double ended arrow that indicates the tolerance zone extends to include multiple surfaces.

Dimension - A numerical value expressed in appropriate units of measure and used to define the size, location, orientation, form, or other geometric characteristics of a part.

.

Feature - A general term applied to a physical portion of a part, such as a surface, hole, or slot.

Feature Control Frame - A rectangular box that is divided into compartments within which the geometric characteristic symbol, tolerance value, modifiers, and datum references are placed

Feature of Size - One cylindrical or spherical surface, or a set of two opposed elements or opposed parallel surfaces, associated with a size dimension.Feature of Size Dimension - A dimension that is associated with a feature of size.

Datum New Activities

You!

End of Day 1

Review Day 1, The Definitions Datums

Datum feature system (planar datums) Datum Feature Simulator, Datum targets

Dimension Basic and Reference, Using Basic Dimension Envelop, actual mating Feature

Control frame, axis Of, Center of Plane, SizeFIM, MMC, LMC,RFS Conditions

Size Actual, Nominal & Virtual Tolerance of Position Controls

Bilateral, Geometric, Unilateral, of positionTrue Geometric Counterpart

Datum - A theoretically exact plane, point or axis from which a dimensional measurement is made.

Datum Feature - A part feature that contacts a datum. 

Datum Target - A symbol that describes the shape, size, and location of gage elements that are used to establish datum planes or axes.

Datum Feature Simulator - The inspection equipment (or gage surfaces) used to establish a datum.

Datum Reference Frame - A set of three mutually perpendicular datum planes.

Datum Shift - The allowable movement, or looseness, between the part datum feature and the gage.

Datum System - A set of symbols and rules that communicate to the drawing user how dimensional measurements are to be made.

Basic Dimension - A numerical value used to describe the theoretically exact size, true profile, orientation, or location of a feature or datum target.

Between Symbol - A double ended arrow that indicates the tolerance zone extends to include multiple surfaces.

Dimension - A numerical value expressed in appropriate units of measure and used to define the size, location, orientation, form, or other geometric characteristics of a part.

.

Feature - A general term applied to a physical portion of a part, such as a surface, hole, or slot.

Feature Control Frame - A rectangular box that is divided into compartments within which the geometric characteristic symbol, tolerance value, modifiers, and datum references are placed

Feature of Size - One cylindrical or spherical surface, or a set of two opposed elements or opposed parallel surfaces, associated with a size dimension.Feature of Size Dimension - A dimension that is associated with a feature of size.

Day 2 Fundamental Rules Dimensioning & Tolerancing

Rule #1 and Rule #2 Basic dimensions

Profile Controls

Profile tolerancing

Workshop Drawing Interpretation

Presentation Q & A Discussion & Closing

comments

Dimensioning & Tolerancing

Selection & arrangement to suit Function and mating relationship

Rule #1 and Rule #2

Profile tolerancing Profile of a surface Profile of a line

Drawing Interpretation Presentation Q & A Discussion

You!