• Choose a category
• All
• Classic-Fiction

If you perform an Insert Bends operation on a model that does not have a consistent wall thickness, then the Flatten Bends and Process Bends features fail. If a thickness face is not perpendicular to the main face of the part, then the software simply forces the situation, making the face perpendicular to the main face.

Using the Normal cut feature

If a Cut feature is placed before the Sheet Metal feature, then as far as SolidWorks is concerned, the part is not a sheet metal part. However, if the cut feature is created after the Sheet Metal feature, then the model has to follow a different set of rules. The “normal shear” mentioned previously is one of those rules. In Figure 21.2, the sketch for a cut is on a plane that is not perpendicular to the face that the cut is going into. Under a normal modeling situation, the cut just goes through the part at an angle. However, in SolidWorks sheet metal, a new option is added to the PropertyManager for the cut. This is the Normal cut option, and it is selected by default. You could be modeling and never even notice this option, but it is important because it affects the geometrical results of the feature.

As shown in Figure 21.39, when the Normal cut option is selected, the thickness faces of the cut are turned perpendicular (or normal) to the face of the sheet metal. This is also important because if the angle between the angled face and the sketch changes, the geometry of the cutout can also change. This setting becomes more important as the material becomes thicker and as the angle between the sketch and the sheet metal face becomes shallower.

SolidWorks allows you to have angled faces on side edges and will maintain the angle when it flattens the part. In previous versions, angles on side faces cause the Flat Pattern feature to fail. Even a cut that does not use the Normal cut option and creates faces that are not perpendicular to the main face of the part will not cause the Flat Pattern to fail.

FIGURE 21.39

Using the Normal cut option

Using the Rip feature

When building a sheet metal part from a generic model, a common technique used to achieve consistent wall thicknesses is to build the outer shape as a solid and then shell the part. The only problem with this method is that it leaves corners joined in a way that cannot be flattened. You can solve this problem by using the Rip feature. Rip breaks out the corner in one or both directions in such a way that it can be unfolded. Bend reliefs are later added automatically by the Process Bends feature.

Figure 21.40 shows the Rip PropertyManager and the results of using this feature. The model was created to look like a Miter Flange part.

Notice also in Figure 21.3 that after the Rip, the edges of the material are still sheared at an angle. Because the top of the part was shelled, the thickness of the part is not normal to the main face of the sheet metal. You can fix this by using the Flatten Bends feature, which lays the entire part out flat, calculates the bend areas, and corrects any discrepancies at the edges of the part.

FIGURE 21.40

Using the Rip feature

Note

Rip functionality is included in the Insert Bends Sheet Metal PropertyManager when it is first initiated, although it is no longer there when you edit the part later. If you use it, the Rip data becomes a feature of its own and is placed before the Sheet Metal feature in the FeatureManager. Be aware that there are slight differences between using the Rip function as an independent feature and using it as a part of the Insert Bends feature. You may want to check this on a part you are working with to verify which method best suits your needs.

Using the Sheet Metal feature

The Sheet Metal feature used in the Insert Bends method is very similar to the one used in the Base Flange method. However, two main differences exist: Insert Bends Sheet Metal requires the user to select a Fixed Face, and Base Flange Sheet Metal allows the use of Gauge Tables. Both features function as placeholders and otherwise