Copyright - Planchard 2012 Part and Drawing Dimensioning Professor Egli EGTECH 10.

Copyright - Planchard 2012

Part and Drawing Dimensioning

Professor Egli

EGTECH 10


Dimensions - General

• Dimensions are used to describe the shape of the part or assembly shown in a drawing view.

• Dimensions in a SolidWorks drawing are associated with the model.

• Changes in the model are reflected in the drawing.


Dimension - Types

• There are two main types of dimensions:– Model dimensions: dimensions created as you

create each part feature. You then insert those dimensions into the various drawing views.


Dimension - Types (Cont:)

• There are two main types of dimensions (cont):– Reference dimensions: Can be added in a

drawing document (driven dimensions). You can’t edit the value of reference dimensions to change the model.


Part Dimensioning - Systems• There are basically three types of

dimensioning systems use in creating parts and drawings:– U.S. - ANSI standard for U.S.

dimensioning use the decimal inch value. When the decimal inch system is used, a zero is not used to the left of the decimal point for values less than one inch, and trailing zeros are used.

– The U.S. unit system is also known as the Inch, Pound, Second (IPS) unit system.

Leading zeros, trailing zeros, and number of zeros to the right of the decimal point are important in dimension and tolerance display.


Part Dimensioning – Systems (Cont:)• There are basically three types of

dimensioning systems use in creating parts and drawings:– Metric - ASME standards for the use of

metric dimensioning required all the dimensions to be expressed in millimeters (mm). The (mm) is not needed on each dimension, but it is used when a dimension is used in a notation. No trailing zeros should be

used. – The Metric or International System of

Units (S.I.) unit system in drafting is also known as the Millimeter, Gram Second (MMGS) unit system.


Part Dimensioning – Systems (Cont:)• There are basically three types

of dimensioning systems use in creating parts and drawings:– Dual Dimensioning - Working

drawings are usually drawn with all U.S. or all metric dimensions. Sometimes the object manufactured requires using both the U.S. and metric measuring system.

– In this illustration, the secondary units (mm) are displayed in parenthesis.

– The Primary units are inches.


Part Dimensioning - Goal

There are different rules for the display of decimal dimensions and tolerances based on millimeter and inch units.


Part Dimensioning - Goal (Cont:)

• What is the goal when dimensioning a part?– Dimensions should be given in a clear and

concise manner and should include everything needed to manufacture and inspect the part exactly as intended by the designer.

– Add Reference dimensions if needed– Add Notes (Local and Global) if needed– Do NOT over dimension the view!


Part Dimensioning - General (Cont:)

• Dimensions of size– How big is it?– height, width, depth,

diameter, etc.

• Dimensions for location– Where is it in space

relative to the origin?


Part Dimensioning - Angle Example

The design of a part may require some lines to be drawn at an angle. The degree is indicated by a symbol º placed after the numerical value of the angle.


Part Dimension - Angle Example (Cont:)

Always position the diameter dimension of a hole up and off the model.

You can insert this dimension


Part Dimension - Angle Example (Cont:)

Note the gap with the dimensions lines and the stager dimensions!

You can insert this dimensioninstead of the .5 dimension.Which is correct?


Part Dimension - Angle Example Cont:

Note: A Reference dimension with no tolerance!

You can insert both dimensionsbut one as a reference dimension ON a Drawing!


Part Dimensioning - Cylinder

What is the Base Sketch Plane?What would the front view look like? What would the Right view look like?What views would you dimension in?



How would you dimension the Cylindrical part in the Horizontal Position?Is there a hole dimension? Do you need both views?



Cylindrical part in the Horizontal Position – Rectangular viewThink of the bushing in the Term Project. Remember Gaps!!!!


Part Dimensioning – Cylinder with a Hole

What is the Base Sketch Plane for the part?Think display mode. What would the Front view look like?What would the Right view look like?How would you dimension the part?


Part Dimensioning - Cylinder with a Hole: Example 1

Cylindrical part – Rectangular view. Holes are dimensioned by giving their diameter and location in the circular view. Remember dimension gaps.

Hidden Lines Visible


Part Dimensioning - Cylinder and Hole1

What would the Front view look like?What would the Right view look like?How would you dimension the part? Note A diameter is identified according to ANSI standards by using the symbol Ø preceding the dimension.



Note A diameter is identified according to ANSI standards by using the symbol Ø preceding the dimension. Note: The model is displayed in millimeters.

Which oneis correct?



What is the Base Sketch Plane?What would the Front view look like? What would the Right view look like?What views would you dimension in?


Part Dimensioning - Example 3

Cylindrical part – Rectangular view. Holes are dimensioned by giving their diameter and location in the circular view.

Centerline

Note Center Mark


Part Dimensioning - Cylinder with a Hole: Example 4

Cylindrical part - Rectangular view. Holes are dimensioned by giving their diameter and location in a circular view.


Part Dimensioning - Radial Dimensions

Foreshortened leader lines and extension lines used on large arcs.

Cylindrical part – Rectangular view. Holes are dimensioned by giving their diameter and location in the circular view.


Part Dimensioning - Square features

Insert the Square symbol if the part is square – not cylindrical. Display in the Rectangular view.


Part Dimensioning - Holes

Holes are often dimensioned in relation to one another and to a finished surface. The preferred method of placing these dimensions is illustrated.


Part Dimensioning - Arc

An arc is always dimensioned by giving the radius. ANSI standards require a radius dimension to be preceded by the letter (symbol) R as illustrated.


Part Dimensioning - General

Smaller (Shorter) dimensions are located closest to the feature line,followed by dimensions of length. Dimensions nearest to the feature lineshould be at least .375inches or (10mm) away from the model and succeedingparallel dimension lines should be at least .250 inches (6mm) apart.


Part Dimensioning - Placement with Polar Coordinates

To dimension features on a round or symmetric component use Constructiongeometry and display sketch entities either on the part or inthe drawing.

Can you create Constructiongeometry in a part?

Can you create Constructiongeometry in a drawing?


Part Dimensioning - Times and By Symbol (X) in a Drawing

The X symbol in a drawing can also be used to indicate the work “by”. For instance, when a slot that has a given width by a specified lengthor a chamfer that has equal sides (.14 X.14)

When used to imply the word “by” a space must precede and follow the capital X symbol.


Part Dimensioning - Times and By Symbol (X) in a Drawing (Cont:)

If the same feature in the model is repeated on the drawing (such as 6 holes of the same diameter and in a pattern) the number of times the instruction applies iscalled out using the symbol X.


Part Dimensioning - ANSI Hole Depth Symbol

Features, such as blind holes and counterbores, must have a depthcalled out to fully describe their geometry.

Deep or Depth Symbol


Part Dimensioning - ANSI Countersink Symbol

The symbol denotes a requirement forcountersunk holes used to recessflathead screws.

Countersink Symbol


Part Dimensioning - ANSI Counterbore Symbol

Counterbore Symbol The symbol denotes a requirement forcounterbored holes used to recessmachine screw head.


Part Dimensioning - ANSI Counterbores and Countersinks


Part Dimensioning - Screw Threads - Drawings Notes


Part Dimensioning - General

Remember dimension line Gaps!!!!


Part Dimensioning - Continuous

Method


Part Dimensioning - Good Practice


Part Dimensioning - Good Practice

Never place dimension on the object!


Part Dimensioning - Over-Dimensioning

Correct (BUT NO GAP) Avoid with not gap

On the Model. You can use Reference dimensionson a drawing!


Part Dimensioning - Coordinate or Baseline Dimensioning

Gap


Part Dimensioning - Center Dimensioning

Note: The order, location and centering of the dimension and dimension lines!

Gap

Copyright - Planchard 2012 Part and Drawing Dimensioning Professor Egli EGTECH 10.

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Transcript of Copyright - Planchard 2012 Part and Drawing Dimensioning Professor Egli EGTECH 10.