2012 Project Lead The Way Inc Introduction to Engineering Design Dimensions should reflect actual size of the object not the scaled size The dimension measured on the drawing is ¾ in but the actual dimension of the part is 2 in Therefore show 200 on drawing ID: 474567
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Slide1
Introduction to Dimensioning
© 2012 Project Lead The Way, Inc.
Introduction to Engineering DesignSlide2
Dimensions should reflect actual size of the object, not the scaled size.The dimension measured on the drawing is ¾ in., but the actual dimension of the part is 2 in. Therefore, show 2.00 on drawing.Slide3
Include overall dimension in the three principle directions – width, height, and depth.Overall dimensions should be placed the greatest distance away from the object so that intermediate dimensions can nest closer to the object.Slide4
Include overall dimension in the three principle directions – width, height, and depth.Overall dimensions should be placed the greatest distance away from the object so that intermediate dimensions can nest closer to the object.Slide5
Include
all dimensions necessary to produce or inspect the part.
Dimensions should be placed so that it is not necessary to calculate or scale a dimension.
?
?
IncorrectSlide6
Include
all dimensions necessary to produce or inspect the part.Slide7
Do
not include unnecessary dimensions.
Incorrect
DUPLICATED
Dimensions should NOT be duplicated or the same information given in two different ways.Slide8
Do
not include unnecessary dimensions.
Incorrect
Do not include chain dimensions that add up to a
given
overall dimension.
Provides the same information in two different ways.Slide9
Do
not include unnecessary dimensions.Slide10
Dimensions
should be attached to the view that best shows the contour of the feature to be dimensioned.
IncorrectSlide11
Dimensions
should be attached to the view that best shows the contour of the feature to be dimensioned.Slide12
A
dimension should be attached to only one view; for example, extension lines should not connect two views.
IncorrectSlide13
A
dimension should be attached to only one view; for example, extension lines should not connect two views.Slide14
Whenever
possible, locate dimensions between adjacent views.
IncorrectSlide15
Whenever
possible, locate dimensions between adjacent views.Slide16
Avoid
dimensioning to hidden lines.
0.75
0.75
IncorrectSlide17
Avoid
dimensioning to hidden lines.
0.75Slide18
Do
not place dimensions on the object unless it is absolutely necessary.
IncorrectSlide19
Do
not place dimensions on the object unless it is absolutely necessary.Slide20
Do
not cross a dimension line with another dimension line or with an extension line. Slide21
Do
not cross a dimension line with another dimension line or with an extension line. Slide22
Avoid
crossing dimension or extension lines with leader lines.
IncorrectSlide23
Avoid
crossing dimension or extension lines with leader lines.
Ø 0.50 THRUSlide24
Leader
lines point toward the center of the feature and should not occur horizontally or vertically.Slide25
Dimension
numbers should be centered between arrowheads, except when using stacked dimensions, and then the numbers should be staggered.
IncorrectSlide26
Dimension
numbers should be centered between arrowheads, except when using stacked dimensions, and then the numbers should be staggered.Slide27
In
general, a circle is dimensioned by its diameter and an arc by its radius.Slide28
Holes
should be located and sized in the view that shows the feature as a circle.
IncorrectSlide29
Holes
should be located and sized in the view that shows the feature as a circle.Slide30
Holes
are located by their centerlines, which may be extended and used as extension lines.Slide31
Notes
Dimensions should reflect actual measurement.No scaling should applyInclude overall dimensions for length, width, and heightThe longest dimension for each direction should be noted
Larger dimensions should be placed farther from the object.Nest shorter dimensions inside longer onesInclude all dimensions necessary to produce or inspect the partYou should be able to pick up any drawing and produce it without having to look at the prototype.Slide32
Notes
Do not include unnecessary or duplicated dimensions.Redundancies are not ‘good documenting,’ they add to confusion.Dimension the view with the best contour.Flat sides are rarely the best contour.
A dimension should be attached to only one view.Look at your extension lines, they should only be drawn to one drawing.Place dimensions between adjacent views.Look at the two views that you are dimensioning. Pick the space between them to write the dimensions.Slide33
Notes
Avoid dimensioning to hidden lines.Sometimes this can’t be avoided. Do not place dimensions on/in the object.All dimensions should be between or outside the drawings.
Do not cross a dimension line with another dimension or with an extension line. same for leader lines – circlesSometimes this can’t be avoided.Leader lines are angled (30°, 45°, or 60°) and point toward the center of the feature.Features are either holes are arcs, so there’s always a center.Slide34
Notes
Center dimension numbers between arrow heads.Dimension circles by diameter, arcs by radiusCircles should be located by the center lines in the view that shows the feature as a circle.Slide35
ReferencesBertoline, G. (2003). Technical graphics communication. (3 ed.). Boston, MA: McGraw-Hill.Giesecke, F. [et al.] (1991). Technical drawing. (9 ed.). New York, NY: Macmillan Pub. Co.Madsen, D., Folkestad, J., Schertz, K., Shumaker, T., Stark, C., & Turpin, J. (2002). Engineering drawing and design. (3 ed.). Albany, NY: Delmar Thomas Learning.