Geometric Dimensioning and
Tolerancing
Other geometric tolerances:
•
•
•
•
•
•
profile
runout & total runout
flatness
angularity
perpendicularity
parallelism
Geometric Characteristics
Form, Orientation, Profile, and Runout Tolerances
EML 2023
Department of Mechanical and Aerospace Engineering
2
Flatness
• Flatness is the condition of a surface where all elements
are in one plane.
EML 2023
Department of Mechanical and Aerospace Engineering
3
Flatness
• The surface could be checked by translating the part
under a dial indicator.
EML 2023
Department of Mechanical and Aerospace Engineering
4
Geometric Characteristics
Form, Orientation, Profile, and Runout Tolerances
EML 2023
Department of Mechanical and Aerospace Engineering
5
Perpendicularity
• Perpendicularity is the condition of an entire surface,
plane, or axis at a right angle to a datum plane or axis.
EML 2023
Department of Mechanical and Aerospace Engineering
6
Perpendicularity
• Perpendicularity is the condition of an entire surface,
plane, or axis at a right angle to a datum plane or axis.
EML 2023
Department of Mechanical and Aerospace Engineering
7
Geometric Characteristics
Form, Orientation, Profile, and Runout Tolerances
EML 2023
Department of Mechanical and Aerospace Engineering
8
Angularity
• Angularity is the condition of an axis or plane other than
90 degrees to another datum plane or axis.
EML 2023
Department of Mechanical and Aerospace Engineering
9
Geometric Characteristics
Form, Orientation, Profile, and Runout Tolerances
EML 2023
Department of Mechanical and Aerospace Engineering
10
Parallelism
• Parallelism is the condition of a surface, center plane, or
axis that is an equal distance at all points from a datum
plane or axis.
bilateral tolerance zone
EML 2023
Department of Mechanical and Aerospace Engineering
11
Parallelism
• Example of a cylinder being parallel to another surface.
EML 2023
Department of Mechanical and Aerospace Engineering
12
Parallelism
• Example of a cylinder being parallel to another cylinder.
EML 2023
Department of Mechanical and Aerospace Engineering
13
Geometric Characteristics
Form, Orientation, Profile, and Runout Tolerances
EML 2023
Department of Mechanical and Aerospace Engineering
14
Profile of a surface
• Profile tolerance is specified for designs where the
surface is to be controlled within a given basic shape.
• Specified for irregular features that are difficult to control
with other form or orientation tolerances.
EML 2023
Department of Mechanical and Aerospace Engineering
15
Profile of a surface
EML 2023
Department of Mechanical and Aerospace Engineering
16
Geometric Characteristics
Form, Orientation, Profile, and Runout Tolerances
EML 2023
Department of Mechanical and Aerospace Engineering
17
Circular Runout
and Total Runout
• The worst circular runout occurs at the slice with the
greatest variation (0.03 mm in this case).
• Total runout is the difference between the highest and
lowest readings found over the entire feature. (0.11 mm
in this case).
EML 2023
Department of Mechanical and Aerospace Engineering
18
19
Circularity vs. Runout
• Can anyone explain the difference between the two and
can they be used on a print interchangeabilty?
• http://www.eng-tips.com/viewthread.cfm?qid=186399
• tp://communities.ptc.com/message/173195
EML 2023
Department of Mechanical and Aerospace Engineering
20
Geometric Characteristics
Form, Orientation, Profile, and Runout Tolerances
EML 2023
Department of Mechanical and Aerospace Engineering
21
GDT Example Problem
1.0
45º
3.6
22
23
HOLE BAR
C
1.500
.750
±.005
B
2.500
.758
.750
.010 M
A
A B C
Datum Plane A
Ø.010 Position
tolerance zone
at MMC
Datum Plane C
1 .5 0 0
.
Datum plane B
2 .5 0 0
24
3.6
HOLE BAR
C
1.500
.750
±.005
B
2.500
.758
.750
.010 M
.005
A B C
A
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
1 .5 0 0
Datum plane B
2 .5 0 0
25
3.6
HOLE BAR
C
1.500
.750
±.005
B
2.500
.758
.750
.010 M
.005
A
A B C
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
1 .5 0 0
.
Datum plane B
2 .5 0 0
.005 Flat
zone
26
3.6
HOLE BAR
C
1.500
.005 A
.750
±.005
B
2.500
.758
.750
.010 M
.005
A
A B C
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
1 .5 0 0
.
Datum plane B
2 .5 0 0
.005 Flat
zone
27
3.6
HOLE BAR
C
1.500
.005 A
.750
±.005
B
2.500
.758
.750
.010 M
.005
A
A B C
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
1 .5 0 0
.005 Perp zone
.
Datum plane B
2 .5 0 0
.005 Flat
zone
28
3.6
HOLE BAR
C
.005 A B
1.500
.005 A
.750
±.005
B
2.500
.758
.750
.010 M
.005
A
A B C
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
1 .5 0 0
.005 Perp zone
.
Datum plane B
2 .5 0 0
.005 Flat
zone
29
3.6
HOLE BAR
C
.005 A B
1.500
.005 A
.750
±.005
B
2.500
.758
.750
.010 M
.005
A
A B C
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
.005 Perp zone
1 .5 0 0
.005 Perp zone
.
Datum plane B
2 .5 0 0
.005 Flat
zone
30
3.6
HOLE BAR
C
.005 A B
1.500
.005 A
B
2.500
2X
.344
.758
.750
.010 M
+ .005
- .002
.750
±.005
.005
A
A B C
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
.005 Perp zone
1 .5 0 0
.005 Perp zone
.
Datum plane B
2 .5 0 0
.005 Flat
zone
31
3.6
HOLE BAR
C
.005 A B
1.500
.500
.005 A
.750
±.005
.600
B
2.500
2X
.344
.758
.750
.010 M
+ .005
- .002
.005
A B C
A
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
.005 Perp zone
1 .5 0 0
.5 0 0
Datum plane B
.6 0 0
2 .5 0 0
.005 Perp zone
.005 Flat
zone
32
3.6
HOLE BAR
C
.005 A B
1.500
.500
.005 A
.750
±.005
.600
B
2.500
2X
+ .005
- .002
.012 M A B C
.344
.758
.750
.010 M
.005
A B C
A
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
.005 Perp zone
1 .5 0 0
.5 0 0
Datum plane B
.6 0 0
2 .5 0 0
.005 Perp zone
.005 Flat
2X Ø.012 Position
zone
tolerance zones at MMC.
33
3.6
HOLE BAR
C
.005 A B
1.500
1.200
.500
.005 A
.750
±.005
.600
B
2.500
2X
+ .005
- .002
.012 M A B C
.344
.758
.750
.010 M
.005
A B C
A
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
.005 Perp zone
1 .5 0 0
1 .2 0 0
.5 0 0
Datum plane B
.6 0 0
2 .5 0 0
.005 Perp zone
. .005 Flat
2X Ø.012 Position
zone
tolerance zones at MMC.
34
3.6
HOLE BAR
C
.005 A B
45°
1.500
1.200
.500
.005 A
.750
±.005
.600
B
2.500
2X
+ .005
- .002
.012 M A B C
.344
.758
.750
.010 M
.005
A B C
A
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
.005 Perp zone
1 .5 0 0
1 .2 0 0
.5 0 0
Datum plane B
.6 0 0
2 .5 0 0
.005 Perp zone
. .005 Flat
2X Ø.012 Position
zone
tolerance zones at MMC.
35
3.6
HOLE BAR
C
R .750
.005 A B
45°
1.500
1.200
.500
.005 A
.750
±.005
.600
B
2.500
2X
+ .005
- .002
.012 M A B C
.344
.758
.750
.010 M
.005
A B C
A
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
.005 Perp zone
1 .5 0 0
1 .2 0 0
.5 0 0
Datum plane B
.6 0 0
2 .5 0 0
.005 Perp zone
. .005 Flat
2X Ø.012 Position
zone
tolerance zones at MMC.
36
3.6
HOLE BAR
.020 A B C
C
R .750
.005 A B
45°
1.500
1.200
.500
.005 A
.750
±.005
.600
B
2.500
2X
+ .005
- .002
.012 M A B C
.344
.758
.750
.010 M
.005
A B C
A
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
.005 Perp zone
1 .5 0 0
1 .2 0 0
.5 0 0
Datum plane B
.6 0 0
2 .5 0 0
.005 Perp zone
. .005 Flat
2X Ø.012 Position
zone
tolerance zones at MMC.
37
3.6
HOLE BAR
.020 A B C
C
X
Y
R .750
.005 A B
45°
X
1.500
1.200
.500
.005 A
.750
±.005
.600
2.500
2X
+ .005
- .002
.012 M A B C
.344
Y
B
.758
.750
.010 M
.005
A B C
A
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
.005 Perp zone
1 .5 0 0
1 .2 0 0
.5 0 0
Datum plane B
.6 0 0
2 .5 0 0
.005 Perp zone
. .005 Flat
2X Ø.012 Position
zone
tolerance zones at MMC.
38
3.6
HOLE BAR
.020 A B C
C
X
Y
R .750
.005 A B
45°
X
1.500
1.200
.500
.005 A
.750
±.005
.600
2.500
2X
+ .005
- .002
.012 M A B C
.344
Y
B
.758
.750
.010 M
.005
A B C
.020 Profile zone between
points X and Y.
.005 Perp zone
1 .5 0 0
1 .2 0 0
Datum plane B
Datum Plane A
Ø.010 Position
tolerance zone
at MMC.
Datum Plane C
.5 0 0
A
.6 0 0
2 .5 0 0
.005 Perp zone
. .005 Flat
2X Ø.012 Position
zone
tolerance zones at MMC.
39
3.6
HOLE BAR
.020 A B C
C
X
Y
R .750
.005 A B
45°
X
1.500
1.200
.500
.005 A
.600
2.500
2X
+ .005
- .002
.012 M A B C
.344
Y
B
.758
.750
.010 M
.750
±.005
.005
A B C
A
.020 Profile zone between
points X and Y.
1 .2 0 0
40
3.6
Geometric Characteristics
Form, Orientation, Profile, and Runout Tolerances
EML 2023
Department of Mechanical and Aerospace Engineering
41