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

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. Copyright - Planchard 2012

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. Copyright - Planchard 2012

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. Copyright - Planchard 2012

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. Copyright - Planchard 2012

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. Copyright - Planchard 2012

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. Copyright - Planchard 2012

Part Dimensioning - Goal There are different rules for the display of decimal dimensions and tolerances based on millimeter and inch units. Copyright - Planchard 2012

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! Copyright - Planchard 2012

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? Copyright - Planchard 2012

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. Copyright - Planchard 2012

Part Dimension - Angle Example (Cont:) You can insert this dimension Always position the diameter dimension of a hole up and off the model. Copyright - Planchard 2012

Part Dimension - Angle Example (Cont:) You can insert this dimension instead of the .5 dimension. Which is correct? Note the gap with the dimensions lines and the stager dimensions! Copyright - Planchard 2012

Part Dimension - Angle Example Cont: You can insert both dimensions but one as a reference dimension ON a Drawing! Note: A Reference dimension with no tolerance! Copyright - Planchard 2012

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? Copyright - Planchard 2012

Part Dimensioning - Cylinder How would you dimension the Cylindrical part in the Horizontal Position? Is there a hole dimension? Do you need both views? Copyright - Planchard 2012

Part Dimensioning - Cylinder Cylindrical part in the Horizontal Position – Rectangular view Think of the bushing in the Term Project. Remember Gaps!!!! Copyright - Planchard 2012

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? Copyright - Planchard 2012

Part Dimensioning - Cylinder with a Hole: Example 1 Hidden Lines Visible Cylindrical part – Rectangular view. Holes are dimensioned by giving their diameter and location in the circular view. Remember dimension gaps. Copyright - Planchard 2012

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. Copyright - Planchard 2012

Part Dimensioning - Cylinder and Hole1 Which one is correct? Note A diameter is identified according to ANSI standards by using the symbol Ø preceding the dimension. Note: The model is displayed in millimeters. Copyright - Planchard 2012

Part Dimensioning - Cylinder and Hole2 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? Copyright - Planchard 2012

Part Dimensioning - Example 3 Center Mark Note Centerline Cylindrical part – Rectangular view. Holes are dimensioned by giving their diameter and location in the circular view. Copyright - Planchard 2012

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. Copyright - Planchard 2012

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. Copyright - Planchard 2012

Part Dimensioning - Square features Insert the Square symbol if the part is square – not cylindrical. Display in the Rectangular view. Copyright - Planchard 2012

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. Copyright - Planchard 2012

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. Copyright - Planchard 2012

Part Dimensioning - General Smaller (Shorter) dimensions are located closest to the feature line, followed by dimensions of length. Dimensions nearest to the feature line should be at least .375inches or (10mm) away from the model and succeeding parallel dimension lines should be at least .250 inches (6mm) apart. Copyright - Planchard 2012

Part Dimensioning - Placement with Polar Coordinates Can you create Construction geometry in a part? geometry in a drawing? To dimension features on a round or symmetric component use Construction geometry and display sketch entities either on the part or in the drawing. Copyright - Planchard 2012

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 length or 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. Copyright - Planchard 2012

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 is called out using the symbol X. Copyright - Planchard 2012

Part Dimensioning - ANSI Hole Depth Symbol Features, such as blind holes and counterbores, must have a depth called out to fully describe their geometry. Deep or Depth Symbol Copyright - Planchard 2012

Part Dimensioning - ANSI Countersink Symbol The symbol denotes a requirement for countersunk holes used to recess flathead screws. Countersink Symbol Copyright - Planchard 2012

Part Dimensioning - ANSI Counterbore Symbol The symbol denotes a requirement for counterbored holes used to recess machine screw head. Copyright - Planchard 2012

Part Dimensioning - ANSI Counterbores and Countersinks Copyright - Planchard 2012

Part Dimensioning - Screw Threads - Drawings Notes Copyright - Planchard 2012

Part Dimensioning - General Remember dimension line Gaps!!!! Copyright - Planchard 2012

Part Dimensioning - Continuous Method Copyright - Planchard 2012

Part Dimensioning - Good Practice Copyright - Planchard 2012

Part Dimensioning - Good Practice Never place dimension on the object! Copyright - Planchard 2012

Part Dimensioning - Over-Dimensioning On the Model. You can use Reference dimensions on a drawing! Correct (BUT NO GAP) Avoid with not gap Copyright - Planchard 2012

Part Dimensioning - Coordinate or Baseline Dimensioning Gap Copyright - Planchard 2012

Part Dimensioning - Center Dimensioning Gap Note: The order, location and centering of the dimension and dimension lines! Copyright - Planchard 2012