Transcript Week 2 GD&T - itt.3d-me

Unit 1
GD&T
Instructor:
James Thornburgh
Agenda:
Inspection & Gauging
5 Steps to GD&T
GD&T in AutoCAD
STP
Inspection & Gauging

Functional Gauging


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Open Gauging



Using Fixtures to check a part
Go/ No-Go Gauges
Using Measurements to inspect
Tells you what is Wrong
Feature of Size

Things that can be directly measured
Functional Gauging
 11.200 ± .002
10.000
15.500
C
 11.200 ± .002
 .001 M A B C
10.000
B
15.500
A
Note: Datum A forms
the bottom surface of
the hole, and so the
tolerance zone is a
perfect, right cylinder –
resting on Datum A
and located from
Datum B and Datum C.
C
 11.200 ± .002
 .001 M A B C
10.000
B
15.500
A
It tells us the size and
shape of the tolerance
zone for the hole
center
C
 11.200 ± .002
 .001 M A B C
10.000
B
15.500
A
In this case, when the
hole is at its’ smallest
permissible size, the
feature location is in
its’ most critical state.
C
 11.200 ± .002
 .001 M A B C
B
A
In this case, when the
hole is at its’ smallest
permissible size and
perfectly located, the
feature is in its’ most
critical state, and just
fits about the red gage
pin.
C
 11.200 ± .002
10.000
15.500
Produced Hole
Size
11.197
M 11.198
11.199
11.200
11.201
11.202
11.203
B
Geometric
Tolerance
.001
.001
.001
.001
.001
 .001 M A B C
Feature Size
‘Bonus’
Total Effective
Tolerance
out of size tolerance
0
.001
.002
.003
.004
out of size tolerance
.001
.002
.003
.004
.005
5 Steps
1.
2.
3.
4.
5.
Isolate & define function
Prioritize the Functions
Identify Datum Reference Frame
Select proper Control
Calculate Tolerance Values
GD&T in AutoCAD

Menu

Dimension
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
Tolerance
Keyboard

tol
GD&T Dialog Box
Diameter
Material Condition
GD&T Dialog Box
STP
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Statistical Process Control
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Process for checking the quality of parts
Keeps track of trends in production
ANSI Limits and Fits
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Running & Sliding
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Locational
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Allow clearance space for lubrication
RC
Between mating parts
LC, LT, LN
Force

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Tight fits
FN
Appendixes 7-11
Lab Assignments
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Lab
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Prob 16.2-16.4