egr166 a engineering graphics/conceptual design · pdf file4 section 9.6.11: metric limits...

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