Intended Audience:
This StAIR is intended for advanced second year students
(10-12 grade) with a mechanical focus.
Objective:
Given the Applying GD&T StAIR a student shall be able to
apply Geometric Dimensioning & Tolerancing schema to
existing models and prints. Based on ASME Y14.5M-1994
standard and aligned with CIP 15.1301 curriculum
requirements.
Purpose:
Today you will be reviewing both the Linear
tolerancing scheme you have been exposed
to as well as being introduced to a new form
of tolerancing and begin applying it on our
prints. That form of tolerancing is called
Geometric Dimensioning & Tolerancing or
simply GD&T
Tolerance defined:
•The permissible range of variation in a dimension of an
object.
•All manufacturing processes must allow for some variances in
part geometry as it is impossible
Two forms of Tolerancing:
Please select one
LINEAR
GD&T
•Based on X&Y coordinates creating a
rectangular tolerance zone for part position.
•Example of tolerance zone
•TYPES OF LINEAR TOLERANCES:
BILATERAL
UNILATERAL
PLUS AND MINUS
LIMIT
•Tolerance dimension that allow variation in
both direction from a basic dimension (+
and -). Does not need to be symmetrical
•EXAMPLE:
•Tolerance dimension that allow variation in
only one direction from a basic dimension (+
or -).
•EXAMPLES:
•Tolerance dimension that used to indicate
the tolerance range above and below the
basic dimension. Must remain symmetrical
•EXAMPLE:
•A statement of the variations that can be
permitted from a given dimension. Stating
both the upper and lower limit of the
dimension
•EXAMPLE:
•Based on an international standard for communicating
instructions about the design and manufacturing of parts.
GD&T uses universal symbols and emphasizes the function
of the part. Culminating in increasing a manufactures
ability to create parts based on form and providing them
with a larger tolerance envelope.
•Tolerance zones GD&T VS Linear
GD&T(ASME) Y14.5M-1994
PURPOSE:
The Y14.5M standard establishes uniform
practices for stating and interpreting
dimensioning, tolerancing, and related
requirements for use on engineering drawings
and in related documents.
TO QUIZ
TO FURTHER INFORMATION
GD&T Can be broken down
into three major categories
TYPES OF
TOLERANCE
DATUM'S &FEATURE
CONTROL FRAMES
MODIFIERS
FORM
PROFILE
ORIENTATION
Geometric tolerances that limit the amount of error in the shape of a
feature. Form tolerances are independent tolerances.
Powerful geometric tolerances that control the size, location, orientation, and
form of a feature. Profile tolerances can be either independent or related.
Geometric tolerances that limit the direction, or orientation, of a feature in
relation to other features. Orientation tolerances are related tolerances.
LOCATION
Geometric tolerances that limit the location or placement of features.
Location tolerances are related tolerances.
RUNOUT
Geometric tolerances that simultaneously limit the form, location, and orientation
of cylindrical parts. Runout tolerances are related tolerances requiring a datum
axis.
STRAIGHTNESS
A two-dimensional geometric tolerance that controls how
much a feature can deviate from a straight line.
FLATNESS
A three-dimensional geometric tolerance that controls how much a
feature can deviate from a flat plane.
CIRCULARITY
A two-dimensional geometric tolerance that controls how much a
feature can deviate from a perfect circle.
CYLINDICITY
A three-dimensional geometric tolerance that controls how
much a feature can deviate from a perfect cylinder.
PROFILE OF A
LINE
A two-dimensional geometric tolerance that controls how much the
outline of a feature can deviate from the true profile.
PROFILE OF A
SURFACE
A three-dimensional geometric tolerance that controls how much a
surface can deviate from the true profile.
ANGULARITY
Perpendicularity
Parallelism
A three-dimensional geometric tolerance that controls how much a surface,
axis, or plane can deviate from the angle described in the design
specifications.
A three-dimensional geometric tolerance that controls how much a
surface, axis, or plane can deviate from a 90 degree angle.
A three-dimensional geometric tolerance that controls how much a surface,
axis, or plane can deviate from an orientation parallel to the specified datum.
Positional
tolerance
A three-dimensional geometric tolerance that controls how much the
location of a feature can deviate from its true position.
Symmetry
A three-dimensional geometric tolerance that controls how much the median
points between two features may deviate from a specified axis or center
plane.
Concentricity
A three-dimensional geometric tolerance that controls how much the median
points of multiple diameters may deviate from the specified datum axis.
CIRCULAR
RUNOUT
TOTAL RUNOUT
A two-dimensional geometric tolerance that controls the form, orientation,
and location of multiple cross sections of a cylindrical part as it rotates.
A three-dimensional geometric tolerance that controls the form, orientation,
and location of the entire length of a cylindrical part as it rotates.
FEATURE
FEATURE CONTROL
FRAME
DATUM'S
DATUM FEATURE
DATUM
REFERENCE FRAME
A physical feature of a part that naturally contains variation and
imperfections. A corner, edge, flat surface, or hole are all examples of
possible features.
A series of compartments containing symbols and values that describe the
tolerance of a feature. The order and purpose of these compartments follow
a consistent standard.
An imaginary, perfect geometric shape or form. A perfect point, line, flat
plane, circle, or cylinder are all examples of possible datums.
A physical feature that acts as an acceptable substitute for a datum. Datum
features relate the various features of the part to each other.
Three imaginary planes perpendicular to one another that are mapped onto
the part to relate features to each other.
Straightness tolerance applied to axis:
What is means:
FLATNESS CALLED OUT
WHAT IS ACTUALLY MEANS
Tolerance applied to cylinder
Implied Meaning:
Tolerance applied
Implied Meaning
Applied to a print
What it implies
Applied to a print
What it implies
ALL AROUND
SYMBOL
BASIC
DIMENSION
BETWEEN
SYMBOL
CONTROL
RADIUS
A circle placed on the bend of the leader line of a profile
control.
A numerical value used to describe the theoretically exact size, true
profile, orientation, or location of a feature or datum target.
A double ended arrow that indicates the tolerance zone
extends to include multiple surfaces.
A radius with no flats or reversals allowed. The symbol for a
controlled radius is "CR."
LEAST MATERIAL
CONDITION
The condition in which a feature of size contains the least amount of
material everywhere within the stated limits of size.
MAXIMUM MATERIAL
CONDITION
The condition in which a feature of size contains the maximum amount
of material everywhere within the stated limits of size.
PROJECTED
TOLERANCE ZONE
A tolerance zone that is projected above the part surface.
RADIUS
A straight line extending from the center of an arc or circle
to its surface.
CONCENTRICITY IS A FORM TOLERANCE
Concentricity
TRUE
FALSE
LOCATION TOLERANCE
Concentricity
A three-dimensional geometric tolerance that controls how much the median
points of multiple diameters may deviate from the specified datum axis.
NEXT QUESTION
OOPS
TOTAL RUNOUT
TRUE
A two-dimensional geometric tolerance that controls the form, orientation,
and location of multiple cross sections of a cylindrical part as it rotates.
FALSE
GOOD WORK
TOTAL RUNOUT
A three-dimensional geometric tolerance that controls the form, orientation,
and location of the entire length of a cylindrical part as it rotates.
NEXT QUESTION
IS THIS THE CORRECT DEFINITION
A three-dimensional geometric tolerance that controls how much a
surface, axis, or plane can deviate from a 90 degree angle.
Parallelism
YES
NO
GOOD WORK
Parallelism
A three-dimensional geometric tolerance that controls how much a surface,
axis, or plane can deviate from an orientation parallel to the specified datum.
NEXT QUESTION
GD&T PROVIDES A DESIGNER AN
IMPROVEMENT IN THE USEABLE
TOLERANCE ZONE OF 52%
TRUE
FALSE
57% INCREASE
NEXT QUESTION
IS THIS CORRECTLY DEFINED
PROFILE OF A
SURFACE
A two-dimensional geometric tolerance that controls how much the
outline of a feature can deviate from the true profile.
YES
NO
GOOD
PROFILE OF A
SURFACE
A three-dimensional geometric tolerance that controls how much a
surface can deviate from the true profile.
NEXT QUESTION
TRUE
FALSE
THIS IS AN EXAMPLE OF A DATUM
REFERENCE FRAME
ALMOST DONE
FEATURE CONTROL
FRAME
A series of compartments containing symbols and values that describe the
tolerance of a feature. The order and purpose of these compartments follow
a consistent standard.
NEXT QUESTION
IS THIS THE CORRECT SYMBOL FOR CIRCULARITY
CIRCULARITY
TRUE
FALSE
GETTING CLOSE
CIRCULARITY
A two-dimensional geometric tolerance that controls how much a
feature can deviate from a perfect circle.
NEXT QUESTION
IS THIS CORRECTLY DEFINED
DATUM'S
An imaginary, perfect geometric shape or form. A perfect point, line, flat
plane, circle, or cylinder are all examples of possible datums.
YES
NO
NICE
NEXT QUESTION
IS THIS THE CORRECT SYMBOL FOR STRAIGHTNESS
A two-dimensional geometric tolerance that controls how
much a feature can deviate from a straight line.
STRAIGHTNESS
YES
NO
NICE WORK
STRAIGHTNESS
A two-dimensional geometric tolerance that controls how
much a feature can deviate from a straight line.
NEXT QUESTION
FORM TOLERANCES ARE
INDEPENDENT FROM OTHER
FEATURES.
TRUE
FALSE
CONGRATULATIONS
PLEASE SEE THE INSTRUCTOR FOR
YOU FIRST ASSIGNMENT
FINISH