tailieunhanh - SolidWorks 2010- P8

SolidWorks 2010- P8: Whether you are a new user of SolidWorks or a professional who wants to improve your skills, this book was written for you. Learning any software can be difficult at times. You launch the software for the first time, and you feel overwhelmed, not knowing how to even start a new document. In 3D CAD programs, it can be especially difficult. Many times a whole new vocabulary and a whole new creative environment are introduced. | Annotate the Drawing 1 7 9 After placing the dimensions for the chamfers you will notice the color difference. Since the chamfer dimensions were not imported from the model they are considered reference dimensions and are not parametrically linked to the actual model. In fact if you were to modify the actual dimension value in the drawing the part model would not update with the change. Instead the link to the part geometry will be broken and even if the part model is updated separately the dimension will still show the edited value. Even though the dimensions show as gray on the screen they can be printed as black we will be covering this later in this chapter. NOTE It is generally considered poor practice to change the value of a . 1 reference dimension since the link to the part geometry will be broken. This will cause the dimension value to remain static regardless of how the part geometry changes in the course of normal revisions. If you can avoid it do not edit reference dimensions in a drawing instead update the part model and the change will be reflected in the drawing. Use the Dimension Palette So far all the dimensions that were added to the drawing were shown with no tolerance other than the tolerance applied in the title block. It is rare that a part drawing doesn t have at least one dimension with a tolerance. This is especially true when the part is destined to be mated to other components. Only in a perfect world would every part of an assembly be manufactured exactly to the dimensions on a drawing. Variations in the manufacturing process will cause a dimension to drift from its nominal value. It is important to keep these variations in mind when dimensioning a part to ensure that the part conforms to its intended form fit and function. Prior to SolidWorks 2010 the only way to add a tolerance to a dimension was by selecting the Tolerance Type and Unit Precision settings in the PropertyManager. Even though that approach was sufficient SolidWorks .