Transcript Week 1 GD&T - itt.3d-me

Unit 1
GD&T
Instructor:
James Thornburgh
Agenda:
Objectives
What is GDT?
Why it’s Important
Measuring
Break
Objectives
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Identify and draw GD&T Symbols
Correctly use GD&T symbols
Describe Maximum and Minimum material
conditions
Describe and correctly apply Datums
Identify various inspection tools
Demonstrate the use of measuring
devices.
What is GD&T?
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GD&T is a way of dimensioning that takes
into account function and fit with related
parts.
Why GD&T is important
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Are Parts Made exactly to the drawings?
GD&T allow drawing to be more accurately
dimensioned, with looser tolerances.
Why GD&T is important
Measuring & Inspection Devices
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Help you to determine if a part is to spec.
Open
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You measure the piece by it’s self
Functional
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You put the piece in a fixture to determine if
it’s good
Go, No-Go Gauges
Calipers
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Vernier
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Dial
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Digital
Reading Vernier Caliper
Reading Vernier Caliper
Micrometers
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Vernier
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Digital
Reading Vernier Micrometer
Surface Plate
Height Gauge
Dial Indicator
CMM
Material Conditions
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MMC
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Maximum Material Condition
When a Feature Weighs the Most
Small Hole, Large Object
LMC
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Least Material Condition
When a Feature Weighs the Least
Large Hole, Small Object
Material Conditions
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RFS
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Material size doesn't matter for Tolerance
GD&T Symbols
Control Types
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Form Controls
Orientation Controls
Location Controls
Form Controls
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Straightness
Flatness
Circularity
Cylindricity
Form Controls
Flatness
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Microscopic View of surface
Flatness
Orientation Controls
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Parallelism
Perpendicularity
Angularity
Profile
Orientation Controls
Angularity
Profile
Location Controls
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Position
Concentricity
Runout
Position
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What is the shape of a normal Tolerance
Zone?
. 02 . 02
2.00±.02
. 02
.75±.02
. 02
Position
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What is the Max it can be out of position?
. 02 . 02
. 03
. 02
. 02
Position
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The Position Tolerance sets a round
Tolerance Zone
Use Basic Dimensions that have Zero
Tolerance
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Symbolized by drawing a Rectangle around
Dim
Position
2.00
Ø2.00
Ø.02
.75
Runout
Defining Datums
Defining Datums
Feature Control Frame
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Houses GD&T Symbols
Datums for Plane
Datums for Axis & Centerline
What do They all Mean?
What do They all Mean?
Datum B
Feature
11.9
12
38.6
0.4
0.5
38.5
0.5
0.6
38.4
0.6
0.7
38.3
0.7
0.8
38.2
0.8
0.9
38.1
0.9
1.0
38.0
1.0
1.1
Lab Assignments & Homework
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Lab
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Measuring Handout
Workbook 16.1-16.3
Homework
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Read Ch 16
Do Review Questions 1-10