Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in...
-
Upload
charles-bruno-paul -
Category
Documents
-
view
228 -
download
0
Transcript of Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in...
![Page 1: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/1.jpg)
Technological DesignBasic Dimensioning
with AutoCAD
How to annotate simple drawings for use in constructing an object
![Page 2: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/2.jpg)
2
Learning Objectives Be able to understand the basic rules of
dimensioning Apply dimensions to objects in accordance
with engineering standards Define the following items: Dimension line,
Extension line, Reference dimension, and Leader
Be able to recognize the following machined holes: Spotfaced, Counterbored, Countersunk, & Counterdrilled.
![Page 3: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/3.jpg)
3
Dimension Terminology:
![Page 4: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/4.jpg)
4
Types of Dimensions
Overall Dimensions Overall : Length, Width, Height
Detail Dimensions All other dimensions
used to describe an object
![Page 5: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/5.jpg)
5
Extension lines Extension lines should be offset from the part by one half the text height and should extend one text height beyond the dimension line
![Page 6: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/6.jpg)
6
Dimension Spacing
The first row of dimensions must be a minimum of 3 text heights away from the part.Any dimensions beyond it must be a minimum of 2 text heights apart
![Page 7: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/7.jpg)
7
Arrowheads: Should be 3 times longer than they are wide.
![Page 8: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/8.jpg)
8
Dimensioning Rules Avoid placing any dimensions on
the part (inside the view) unless there is no other option.
Avoid dimensioning to hidden features
Always place the dimension where the characteristic shape is shown in the most descriptive view. (This means don’t place a dimension on object lines making a “T joint”.)
Always dimension holes in their circular view by stating the diameter of drilled holes. Specify the hole depth of special features such as countersinking with a note following the dimension.
Dimension rounded corners and arc features as radii where they appear in their rounded views.
If the same value is repeated many times, then use a general note for the features.
Dimension cylindrical objects as diameters in their rectangular view.
Always place the first row of dimensions a minimum distance of 3 text heights away from the edge of the part. Additional stacks can be a minimum of 2 text heights away from each other.
Keep dimensions between the views whenever possible
Extension lines may cross each other and over other lines on the part, but dimension lines should never be crossed.
The overall dimension should always be given. It should be placed outside of smaller dimensions and be the furtherest dimension from the part.
See Essentials of Engineering Design Graphics Chapter 4
![Page 9: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/9.jpg)
9
Do not duplicate dimensions and avoid using unnecessary or superfluous dimensions
When all of the dimensions are expressed in inches, do not use inch mark (“) or the abbreviation for inches (in.)
For drawings dimensioned in inches, values less that one inch should not be preceded with a zero.
For metric drawings, omit the use of the millimeter (mm) notation following the numeral, as millimeters are the default units.
The origin for baseline or ordinate dimensions used as a datum should be extended from a finished edge of the part.
Conserve space and time by using abbreviations and standardized symbols whenever possible.
Reference dimensions should be placed in parentheses or should include the abbreviation “REF”.
Basic sizes (to be toleranced) should be placed inside a rectangular box
Extend leaders from the first of last word in a note. Point them toward the center of circular features that they are specifying.
Place dimensions among the various views to avoid crowding. Stagger horizontal dimensions to avoid contact or crowding of values.
Dimensioning Rules
See Essentials of Engineering Design Graphics Chapter 4
![Page 10: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/10.jpg)
10
1. Avoid placing dimensions on the part (inside of the view).
See Essentials of Engineering Design Graphics Chapter 4
![Page 11: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/11.jpg)
11
2. Avoid dimensioning to hidden features
There is one exception:……When the hidden line is a finished (√) surface
See Essentials of Engineering Design Graphics Chapter 4
![Page 12: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/12.jpg)
12
3. Always place dimensions where the characteristic shape is shown in the most descriptive view
See Essentials of Engineering Design Graphics Chapter 4
![Page 13: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/13.jpg)
13
4. Always dimension holes in their circular view with the Ø. Specify special features (hole types) with a note.
Also:Also: Remember to locate hole position with ordinate dimensions to hole centers
See Essentials of Engineering Design Graphics Chapter 4
![Page 14: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/14.jpg)
14
5. Dimension rounded corners and arc features as radii where they appear in their rounded view.
See Essentials of Engineering Design Graphics Chapter 4
![Page 15: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/15.jpg)
15
6. If the same value is repeated many times, then use a general note for the feature. (ALL FILLETS AND ROUNDS ARE .125R)
See Essentials of Engineering Design Graphics Chapter 4
![Page 16: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/16.jpg)
16
7. Dimension cylinders in their rectangular view with a diameter symbol….Ø.
See Essentials of Engineering Design Graphics Chapter 4
![Page 17: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/17.jpg)
17
8. Place the first row of dimensions 3 text heights (3/8 ”or 10 mm) away from the edge of the part.
Additional stacks of dimensions can be a minimum of two text heights (1/4 ”or 6 mm) away from each other See Essentials of Engineering Design Graphics
Chapter 4
![Page 18: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/18.jpg)
18
9. Keep dimensions between views whenever possible .
See Essentials of Engineering Design Graphics Chapter 4
![Page 19: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/19.jpg)
19
10. Extension lines may cross each other and over other lines on the part, but dimension lines should never be crossed. (Hint no “arrow-headed” lines can cross “arrow-headed” lines)
See Essentials of Engineering Design Graphics Chapter 4
![Page 20: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/20.jpg)
20
11. The overall dimension should always be given. It should be placed outside of smaller dimensions and be the farthest from the part.
See Essentials of Engineering Design Graphics Chapter 4
![Page 21: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/21.jpg)
21
12. Do not duplicate dimensions and avoid using unnecessary or superfluous dimensions
See Essentials of Engineering Design Graphics Chapter 4
![Page 22: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/22.jpg)
22
13. When all of the dimensions are expressed as inches. DO NOT use inch marks ('') or the abbreviation (.in)
See Essentials of Engineering Design Graphics Chapter 4
![Page 23: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/23.jpg)
23
14. For drawings dimensioned in inches, values less than 1 inch should not be proceeded with a zero.
See Essentials of Engineering Design Graphics Chapter 4
![Page 24: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/24.jpg)
24
15. For metric dimensions less than 1 mm DO place a zero in front of the decimal point.
See Essentials of Engineering Design Graphics Chapter 4
![Page 25: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/25.jpg)
25
16. For metric drawings, omit the use of the millimeter (mm) notation following the numeral, as millimeters are the default units.
See Essentials of Engineering Design Graphics Chapter 4
![Page 26: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/26.jpg)
26
17. The origin for baseline or ordinate dimensions used as a datum should be extended from a finished edge of the part.
See Essentials of Engineering Design Graphics Chapter 4
![Page 27: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/27.jpg)
27
18. Conserve space and time by using abbreviations and standardized symbols whenever possible.
See Essentials of Engineering Design Graphics Chapter 4
![Page 28: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/28.jpg)
28
19. Reference dimensions should be placed in parenthesis or should include the abbreviation “REF”. Basic sizes (to be toleranced) should be placed inside of a rectangular box
See Essentials of Engineering Design Graphics Chapter 4
![Page 29: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/29.jpg)
29
20. Extend leaders from the first or last word in a note. Point them toward (but not touch) the center of the circular features that they are specifying.
See Essentials of Engineering Design Graphics Chapter 4
![Page 30: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/30.jpg)
30
21. Place dimensions among the various views to avoid crowding. Stagger horizontal dimensions to avoid contact or crowding of the values
See Essentials of Engineering Design Graphics Chapter 4
![Page 31: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/31.jpg)
31
Angular features:Dimension angular features with either:
X,Y coordinate location or Vertex location & degrees
See Essentials of Engineering Design Graphics Chapter 4
![Page 32: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/32.jpg)
32
Dimension StylesUnidirectional dimensions are read from the lower left corner of the sheet
Aligned dimensions align with individual dimension lines.
See Essentials of Engineering Design Graphics Chapter 4
![Page 33: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/33.jpg)
33
A short review on Dimension “elements”•What is…
•an Extension line ?•an Extension line gap ?•an Extension line extension ?•a Dimension line ?•a Dimension numeral ?•a leader ?
•When are…
•Decimals used ? Not used ?•Unit designators (in. or mm) listed on dimension lines ?
•What size…
•Is an Arrowhead ?
![Page 34: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/34.jpg)
34
Dimensioning Errors: What is wrong with:
![Page 35: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/35.jpg)
35
Dimensioning Errors: What is wrong with:
![Page 36: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/36.jpg)
36
Dimensioning Errors: What is wrong with:
![Page 37: Technological Design Basic Dimensioning with AutoCAD How to annotate simple drawings for use in constructing an object.](https://reader033.fdocuments.net/reader033/viewer/2022051316/5697bf841a28abf838c86fa8/html5/thumbnails/37.jpg)
37
Dimensioning Errors: What is wrong with: