SolidWorks 2011 Parts Bible - Matt Lombard [281]
FIGURE 21.19
The Start/End Offset settings for a Miter Flange
Using the Hem feature
The Hem feature is used to roll over the edge of a sheet metal part. This feature is often used to smooth over a sharp edge or to add strength to the edge. You can also use it for other purposes, such as to capture a pin for a hinge. SolidWorks offers four different hem styles — Closed, Open, Tear Drop, and Rolled — which are shown as icons on the Hem PropertyManager. The PropertyManager for the Hem feature is shown in Figure 21.20.
One of the limitations to keep in mind with regard to hems is that SolidWorks cannot fold over a part so that the faces touch perfectly line on line. Doing this would cause the two sections of the part to merge into a larger piece, thus removing the coincident faces. SolidWorks, computers, and mathematics in general do not always handle the number zero very well. In reality, you can often see light through these hems, and so a perfectly flush hem may not be as accurate as it seems.
You can edit the profile of the Hem, like an Edge Flange, to control the length of the edge that is hemmed. To do this, click the Edit Hem Width button below the Edges selection box in the Hem PropertyManager, shown in Figure 21.20.
FIGURE 21.20
The Hem PropertyManager and a sample hem
Using the Jog feature
The Jog feature puts a pair of opposing bends on a flange so that the end of the flange is parallel to, but offset from, the face where the jog started. The Jog PropertyManager and a sample jog are shown in Figure 21.21.
The Jog feature is created from a single sketch line on the face of a sheet metal part. The geometry to be jogged should not have any side bends; it should be a simple tab-like flange, as shown in Figure 21.21. The line to create the jog can be drawn at an angle, causing the jog to also be angled.
The three icons on the Jog Offset panel illustrate what dimension is being controlled by that setting.
Fixed Face
Like most sheet metal features, the Jog feature bends faces on the part, and when it does so, although it may be obvious to you as the user, it is not obvious to the software which face should remain stationary and which faces should be moved by the bend. The Fixed Face selection box enables you to select a face, or in this case, a part of a face, that you want to remain stationary as the rest of the faces move. The black dot on the face identifies it as stationary.
Tip
Problems can sometimes arise when you are using configurations that change sizes, because these markers for fixed faces can be pushed onto other faces. This can cause problems with assemblies and drawings, and in general makes visualization difficult. In cases like this, it may be advisable to select a larger face or one that has fewer changes, if possible, to be used as the fixed face.
FIGURE 21.21
The Jog PropertyManager and a sample jog
Jog Offset
You can control the direction of the jog by using the arrow button to the left of the end condition selection box. You can control the jog distance by selecting the end conditions Up To Surface, Up To Vertex, or Offset From Surface. The default setting is Blind, in which you simply enter a distance for the offset, in exactly the same way that end conditions are controlled for features such as extrudes.
Fix projected length
One setting that may not be obvious is the Fix projected length. This refers to the length of the flange that the jog is altering. In Figure 21.19, you can see that the height of the jogged feature is the same as the height of the original feature. The jog obviously requires more material than the original, but the Fix projected length option is selected, and so the height is maintained. If you deselected this option, then the finished height of the flange after the jog is added would be shorter, because the material is used by the jog and additional material