SolidWorks 2011 Parts Bible - Matt Lombard [280]
Flange Position
The small icons for Flange Position should be fairly self-explanatory, with the dotted lines indicating the existing end of the material. The names for these options, in order from left to right, are
• Material Inside
• Material Outside
• Bend Outside
• Bend From Virtual Sharp (for use when an angle is involved)
Trim side bends
In situations where a new flange is created next to an existing flange, and a relief must be made in the existing flange to accommodate the new flange, you can select the Trim side bends option to trim back the existing flange. Leaving this option unselected simply creates a relief cut, as shown in Figure 21.16. This is functionality that requires some imagination from the user. A real sheet metal part manufactured like this would have an area at the corner where the deformation from the bends in different directions overlaps. This overlapping bend geometry is too complex for SolidWorks to create automatically, so it offers you a couple of options for how you would like to visually represent the corner. The Flat Pattern is correct, but the formed model requires some imagination.
FIGURE 21.16
Using the Trim side bends option
Curved edges
Edge Flanges can be created on curved edges, but the curved edge must be on a planar face. For example, if the part were the top of a mailbox, then an Edge Flange could not be put on the curve on the top of the mailbox. The flange would have to be made as a part of the flat end of the mailbox, instead.
Figure 21.17 shows Edge Flanges used on a part. Notice that reliefs are added to the ends of the bends, although they are not really needed.
FIGURE 21.17
Curved Edge Flanges on a part
All the edges that you select to be used with a curved Edge Flange must be tangent. This means that in Figure 21.17, neither of the Edge Flanges could have been extended around the ends of the part. You would need to create separate Edge Flange features for those edges.
Because these Edge Flanges are made in such a way that they are developable surfaces, they can be (and are) flattened in such a way that they do not stretch the material of the flange when the flat is compared to the formed shape. Doubtless there is some deformation in between the two states in the actual forming of this flange, and so its manufacturing accuracy may not be completely reliable.
Using the Miter Flange feature
The Miter Flange feature can create picture frame–like miters around corners of parts, and correctly recognizes the difference between mitered inside corners and mitered outside corners. The PropertyManager and a sample Miter Flange are shown in Figure 21.18.
FIGURE 21.18
The Miter Flange PropertyManager and a sample part
A Miter Flange feature starts off with a sketch that is perpendicular to the starting edge of the Miter Flange feature.
Tip
A quick way to start a sketch for a Miter Flange that is on a plane perpendicular to a selected edge is to select the edge, and then click a sketch tool. This automatically creates a plane perpendicular to the edge at the nearest endpoint.
Miter Flange sketches can have single lines or multiple lines. They can even have arcs. Still, remember that just because you can make it in SolidWorks does not mean that the manufacturer can make it. It is often a good idea to check with the manufacturer to ensure that the part can be made. Also, you usually learn something from the experience.
Tip
When selecting edges for the Miter Flange to go on, be sure to remain consistent in your selection. If you start by selecting an edge on the top of the part, then you should continue selecting edges on the top of the part. If you do not, then SolidWorks prompts you with a warning message in a tool tip that says that the edge is on the wrong face.
Some of the controls in the Miter Flange PropertyManager should be familiar by now, such as Use default radius, Flange Position, Trim side bends, and Gap Distance. You have seen these controls before in the Edge Flange PropertyManager.
The Start/End Offset panel enables