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EGR166 A
Engineering Graphics/Conceptual Design
Ankeny Campus
Arts & Sciences
Lecture 34
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November 30th, 2011
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Outline
Turn in Homework 30
Attendance
Quiz 30
Section 9.6.11: Metric Limits & Fits
Section 9.6.12: English Units Standard Fits
Section 9.8: Surface Texture Symbols
AutoCAD
Tolerance basics
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Outline
Return & go over
• Homework
• Quiz
Assign Homework 31
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Section 9.6.11: Metric Limits & Fits
standards for metric tolerances set by ISO (ANSI B4.2-1978)
example of hole & shaft (Figure 9.61)
40H8
• “40”: basic size (mm)
• “H”: hole
• “8”: international tolerance (IT) grade
40f7
•“40”: basic size (mm)
• “f”: shaft
• “7”: international tolerance grade
the smaller the IT grade, the tighter the fit (Figure 9.64)
ANSI Standard B4.1 for cylindrical parts (Appendixes 3-7)
different fit classes
running & sliding fits (RC): always clearance fit
clearance locational fits (LC): clearance fit up to line-to-line fit
transition locational fits (LT): clearance to transition fit
interference locational fits (LN): line-to-line fit to transition fit
force & shrink fits (FN): always interference fit
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Section 9.6.12: Standard Precision Fits: English Units
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Class Exercise 5: Using Precision Fit Tables
1. Select fit class: FN 2 (Figure 9.73)
2. Nominal dimension: 0.5000”
3. Shaft s6: +1.6 & +1.2
4. 0.0016” & 0.0012”
5. Shaft dimension:
a. Upper limit: 0.5016”
b. Lower limit: 0.5012”
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Class Exercise 5: Using Precision Fit Tables
6. Hole H7: +0.7 & -0
7. 0.0007” & 0.0000”
8. Hole dimension:
a. Upper limit: 0.5007”
b. Lower limit: 0.5000”
9. Conclusion: interference fit because hole always smaller than
shaft
surface texture: texture of surface
surface texture important for many purposes:
• friction
• aerodynamics
symbols for surface texture (Figure 9.74, 9.75, & 9.76)
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Section 9.8: Surface Texture Symbols
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Tolerance Basics
1. Draw rectangle:
a. Home tab → Draw → Rectangle
b. Command Window: RECTANGLE
2. Specify 1st corner: 0,0
3. Specify other corner: 4,3
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Tolerance Basics
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Unilateral Tolerance
4. Dimension Style:
a. Annotate tab → Dimensions → arrow
b. Command Window: JOIN
5. New Dimension Style
6. Copy Standard
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Unilateral Tolerance
7. Primary tab:
a. Precision: 0.00
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Unilateral Tolerance
8. Tolerances tab:
a. Method: Symmetrical
b. Precision: 0.00
c. Upper value: 0.10
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Unilateral Tolerance
9. Linear command
a. Annotate tab → Dimensions → Linear
b. Command Window: DIMLINEAR
10. Specify 1st dimension line origin
11. Specify 2nd dimension line origin
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Unilateral Tolerance Finish
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Bilateral Tolerance
12. Dimension Style:
a. Annotate tab → Dimensions → arrow
b. Command Window: JOIN
13. New Dimension Style
14. Copy Copy Standard
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Bilateral Tolerance
15. Tolerances tab:
a. Method: Symmetrical
b. Precision: 0.00
c. Upper value: 0.02
d. Lower value: 0.03
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Bilateral Tolerance
16. Linear command
a. Annotate tab → Dimensions → Linear
b. Command Window: DIMLINEAR
17. Specify 1st dimension line origin
18. Specify 2nd dimension line origin
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Tolerance Basics Final
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constructive solid geometry: the technique of using geometric
primitives to construct more complicated models
3 Boolean operations
• also known as “algebra of sets”
• utilized for other applications
asfsd
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Section 4.7: Template
http://library.thinkquest.org/C0126820/algebra.html
http://www.rci.rutgers.edu/~cfs/305_html/Induction/Lattices.html
Introduction to engineering design
Going to learn (and do!) two things
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Section : Template
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Section : Template
1. Introduction to engineering design
2. Going to learn (and do!) two things
a. Conceptual Design
b. Engineering Graphics
Introduction to engineering design
Going to learn (and do!) two things
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Template
Wheel
Pan
Zoom
Orbit
Slow Motion
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