SolidWorks 2011 Parts Bible - Matt Lombard [310]
3. Select an existing circular edge to align the boss. The new boss will be concentric with the circular edge. This step is also optional. You can choose to use dimensions to locate the boss after the feature is created. If you use dimensions, you cannot locate the boss while the PropertyManager is active.
4. The Boss panel of the Mounting Boss PropertyManager is used to establish the height and other dimensions of the central boss. Diameter and draft dimensions are obvious. You can establish height by a dimension or by an “up to” face using the Select mating face option. There is no option for an “offset from face” end condition.
5. The Fins panel of the Mounting Boss PropertyManager is used to control the alignment, draft, height, width, and patterning of the ribs around the boss. The first box is for a direction vector such as a plane, edge, or axis to establish the rotational orientation of the ribs. You cannot use a sketch for this. The significance of the dimensional values is obvious. The fin pattern function is also obvious except for the Equally Spaced option, which is only available when the number selected is 2. Then you must select a vector to establish the orientation of the fins, which form a right angle for a corner.
6. The Mounting Hole/Pin panel enables you to specify a pin or hole boss and the associated sizes. It is interesting to me that it doesn't enable through holes or counterbore holes from the outside of the part, along with associated screw sizes for clearance.
7. SolidWorks has renamed Favorites in the rest of the software to Styles, but in the Mounting Boss and the Lip/Groove, it is still called Favorites, and saves settings like other Favorites/Styles functionality.
8. After you have successfully accepted the creation of the boss, if you did not use a circular edge to locate the boss (Step 3), you can expand the Mounting Boss feature in the FeatureManager and edit the 3D sketch under the boss. Inside this sketch is a point, which you can dimension to locate precisely. Remember that dimensions in 3D sketches follow some special rules. To get orthogonal dimensions parallel to X, Y, or Z axes, you will need to dimension from planes. Three-dimensional sketch dimensions do not snap to horizontal or vertical orientations like 2D sketches.
If you have selected a flat face for the initial position of the boss, you get a 2D sketch instead of a 3D sketch.
FIGURE 24.1
A Mounting Boss in progress
The features created by this tool are not manually editable. They are not made of extrudes and rib features that are accessible behind the Mounting Boss interface. You have to go through the Mounting Boss PropertyManager to edit the features and cannot edit sketches used to make the features.
SolidWorks designed this feature primarily as a way to create pin-and-hole press pin bosses. These are certainly needed, but also needed are screw bosses. You will have to size your own screw holes either for threaded inserts or for thread cutting screws. You will also need to manually create some of your own features if you want to make a counterbored clearance hole for a screw, as shown in the cross section in Figure 24.2.
FIGURE 24.2
Manually making a Mounting Boss into a typical screw boss
In this case, I created the screw boss by creating a Mounting Boss feature with a hole sized for the screw, then added an extrude around the base of the boss, and a cut from the outside to shell out the boss. The list of features is shown to the left in Figure 24.2. You might also consider using the Indent feature with a tool body the size of the hole you want to create.
An effective way to pattern a single Mounting Boss feature around a part is to use the Sketch Driven Pattern. This feature uses a sketch with a set of points where each point represents the center of a patterned instance. Refer to the model on the DVD and examine the sketch driven pattern at the bottom of the FeatureManager. Use the Chapter 24 – right frame.sldprt file, and change to the “nonmirror