Working with Bends and Junctions

Two adjacent flanges of sheet metal parts are connected by a bend or a junction. Different from many other mechanical CAD systems, bends and junctions are separate features in BricsCAD®. A bend can be switched to a junction and vice versa, which allows you to easily fix or optimize the unfolded representation of a sheet metal part.

Converting Hard Edges to Bends or Junctions

If adjacent flanges of a sheet metal part are not connected by a bend or junction, the part cannot be unfolded or exported to a CAM system. Therefore, such hard edges must be converted to bends or junctions.

Converting hard edges to bends

  1. Do one of the following:
    • Hover over a hard edge and click the Create Bend () tool in the Quad menu.

    • Click the Create Bend () tool button in the Sheet Metal ribbon tab.

    • Choose Create Bend in the Sheet Metal menu.

    • Type SMBEND in the Command line.

      You are prompted:

      Select hard edges or junctions or flanges or 3D solids or [Entire model/selection options (?)] <Entire model>:

  2. Select a flange face or a hard edge.

    You are prompted:

    Entities in set: 1

    Select flange faces or hard edges:

  3. Do one of the following:
    • Select more faces or hard edges.
    • Right-click or press Enter to create the bends or junctions on the selected items.
Selected a hard edge A bend is created

Converting Hard Edges to Junctions

  1. Do one of the following:
    • Hover over a hard edge and click the Create Junction () tool in the Quad menu.

    • Click the Create Junction () tool buttons in the Sheet Metal ribbon tab.

    • Choose Create Junction in the Sheet Metal menu.

    • Type SMJUNCTION in the Command line.

      You are prompted: Select hard edges or bends or flanges or 3D solids [Entire model/selection options (?)] <Entire model>:

  2. Select a flange face or a hard edge.

    You are prompted:

    Entities in set: 1

    Select flange faces or hard edges:

  3. Do one of the following:
    • Select more faces or hard edges.
    • Right-click or press Enter to create the bends or junctions on the selected items.
Selected hard edges.

Notice that a corner relief must be created first.

Junctions created.

Notice that unnecessary material cuts have been removed due to Smart Features.

Creating Curved Junctions

Lets have a look at a more complex scenario where a junction has to be cut over a non-linear edge. To make the part unfoldable, you need to:
  • Cut the bend relief for one of the linear hard edges.

  • Cut the junctions for the remaining linear and curved hard edges.

  • Create a bend on the remaining hard edge.

  1. Create bend reliefs.

    Do one of the following:

    • Click the Create Relief tool button () on the Sheet Metal ribbon tab.

    • Choose Create Relief in the Sheet Metal menu.

    • Type SMRELIEF in the Command line.

      You are prompted:

      Select a hard edge or bend face, flange face, 3D solid [Entire model/selection options (?)] <Entire model>:

  2. Select a hard edge.

    You are prompted:

    Select another hard edge or bend face for the corner relief:

  3. Press Enter or right-click.

    You are prompted:

    Enter relief size by bend radius ratio or [force Bend reliefs/Auto] <Auto>:

  4. Press Enter or right-click.

    2 bend reliefs are created for the edge:

    2 bend reliefs are created because a hard edge side with a free vertex needs a relief in order to make orthogonal thickness face.

    A bend relief on the side adjacent to the lofted bend is created because this feature is different from a regular bend: creating a corner relief there would be too big.

  5. Create 2 junctions.

    Do one of the following:
    • Click the Create Junction () tool buttons in the Sheet Metal ribbon tab;

    • Choose Create Junction in the Sheet Metal menu;

    • Type SMJUNCTION in the command bar.

      You are prompted:

      Select hard edges or bends or flanges or 3D solids [Entire model] <Entire model>:

  6. Select the following 3 hard edges:

    Consider the small hard edge:

    The cut is created. Parts which corresponded to linear edge get regular junction features.

  7. Create a bend on the hard edge. Because it is the only hard edge left on the model, apply the command to the entire model.
    • Click the Create Bend () tool buttons in the Sheet Metal ribbon tab.

    • Choose Create Bend in the Sheet Metal menu.

    • Type SMBEND in the Command line.

      You are prompted:

      Select hard edges or junctions or flanges or 3D solids or [Entire model] <Entire model>:

  8. Press Enter.

    The bend is created.

  9. Unfold the part.
    • Click the Unfold Body () tool buttons in the Sheet Metal ribbon tab.

    • Choose Unfold Body in the Sheet Metal menu.

    • Type SMUNFOLD or the Command line.

      You are prompted:

      Select a flange or lofted bend face to start unfolding [Associative]:

  10. Select some flange face.

    You are prompted:

    Select position of the unfolded body:

  11. Place the unfolded part.

    You are prompted:

    Validate the unfolded body and select an option [save 2D geometry/save 3D geometry/Optimize bend annotations/Keep] <Keep>:

  12. Press Enter to keep the result.

To Split a Thickness Face

To extend a flange which shares the same thickness face with other flanges, the thickness face must be split.

  1. Launch the SMIMPRINT command ().

    Prompts you: Select a thickness face:

  2. Select the shared thickness face.
  3. Right-click or press Enter to split the face.
  4. The flanges can now be extended separately:
  5. Execute the DMSIMPLIFY command to remove the unneeded splits, thus unifying the coplanar thickness faces.

Changing the Bend Radius

To change the overall bend radius:

  1. Select the root node in the Mechanical Browser.
  2. Find the Bend radius group in the bottom part of the Mechanical Browser.
  3. Do one of the following:
    • Set Type to Absolute Value, then type the radius value in the Value field.

      The Bend Radius field changes accordingly.

    • Set Type to Thickness ratio, then type a value in the Value field.

      The Bend Radius field is calculated as the product of the Thickness and the Thickness ratio.

To change the bend radius for a particular bend:

  1. Select the bend node in the Mechanical Browser. The selected bend highlights in the model. The Bend Properties display in the bottom part of the Mechanical Browser.
  2. Do one of the following:
    • Set the Type to Global value.

      The current global bend radius is applied to the selected bend.

    • Set the Type to Absolute value, then type the radius value in the Value field.

      The Bend Radius field changes accordingly.

    • Set the Type to Thickness Ratio and type a value in the value field.

      The Bend Radius field is calculated as the product of the Thickness and the Thickness ratio.

Changing the Junction Gap

To change the overall junction gap:

  1. Select the root node in the Mechanical Browser.
  2. Locate the junction gap group in the bottom part of the Mechanical Browser.
  3. Do one of the following:
    • Set Type to Absolute Value, then type the gap value in the Value field.

      The junction gap field changes accordingly.

    • Set Type to Thickness ratio, then type a value in the Value field.

      The junction gap field is calculated as the product of the Thickness and the Thickness ratio.

To change the junction gap for a particular bend:

  1. Select the bend node in the Mechanical Browser. The selected bend highlights in the model. The Bend Properties display in the bottom part of the Mechanical Browser.
  2. Do one of the following:
    • Set the Type to Global value.

      The current global junction gap is applied to the selected bend.

    • Set the Type to Absolute value, then type the gap value in the Value field.

      The junction gap field changes accordingly.

    • Set the Type to Thickness Ratio and type a value in the Value field.

      The junction gap field is calculated as the product of the Thickness and the Thickness ratio.

Changing the Junction Type

By default, BricsCAD® creates symmetric junctions, as shown in the image below:

The SMJUNCTIONSWITCH command allows changing a symmetrical junction feature to one with overlapping faces.

To change the junction type using the Quad menu:

  1. Hover the cursor over one the thickness faces of this junction.
  2. Select Switch Junction Type in the Sheet Metal command group in the Quad menu.

    The selected thickness face is aligned with the flange face.

To change the junction type in the Mechanical Browser:

Method 1:

  1. Select the corresponding junction in the tree.

    The junction properties display in the bottom part of the Mechanical Browser.

  2. Select the Connection type property.

  3. Choose the desired junction type.

    The options are: Symmetric, Aligned to Flange_X or Aligned to Flange_Y.

    Figure 1. Junction properties

    The junction is updated accordingly.

Method 2:

  1. Select the corresponding junction in the tree.

    A context menu displays:

  2. Right-click and choose Switch type of feature in the context menu.
Note: Both symmetric and aligned junctions maintain the same gap value between connected flanges.