Flange: Base and Edge

Overview#

Flange is the main creation command in Fusion's Sheet Metal tab. One command covers three types: a base flange (a flat sheet from a closed sketch profile), an edge flange (a wall added to an existing sheet metal edge), and a contour flange (a multi-bend wall from an open profile; see the contour flange page). Fusion decides which one you are making from what you select.

Where to find it#

• Design > Sheet Metal > Create > Flange. Autodesk's help confirms one dialog with a Flange (Base/Edge/Contour) type. Hold Ctrl (Cmd on macOS) to modify the selection after the preview appears.
• Right-click marking menu: Create > Flange (verify in your version).
• Selecting a sheet metal edge in the canvas and starting Flange gives an edge flange.

Step by step#

Base flange#

1. Create a sketch with a closed profile, for example a 100 x 60 mm rectangle with rounded corners.
2. Finish the sketch, then start Flange.
3. Select the profile. One or more closed profiles can be selected; unconnected profiles each create a separate body. If the component has no rule, pick one in the Sheet metal rule dropdown.
4. Set the Orientation: Side 1, Side 2 or Center. This decides which side of the profile the sheet extrudes to, or whether the thickness is split evenly.
5. Choose Operation: New body (a separate body in the active component) or New component.
6. Click OK.

Edge flange#

1. Start Flange and click one or more sheet metal edges (edges on the thickness face of the base flange work; Fusion highlights valid edges).
2. Choose a flange width type:
   • Full edge: the flange spans the whole selected edge.
   • Symmetric: set a Distance; centred on the edge midpoint.
   • Two sides: Distance 1 and Distance 2 from the midpoint.
   • Two offsets: pick Reference 1 and Reference 2 and offsets to place the flange between two features.
3. Pick the Extent type: Distance (the default, set Height by value or handle) or To object (extend up to a face, plane or body; available only with a single edge, and the target must be planar and parallel to the edge; an optional Offset can be applied).
4. Set the Angle with the rotation handle or by typing.
5. Choose the Height datum (shown with the Distance extent): Inner faces (from the intersection of the inner faces of the base and the new flange), Outer faces (from the intersection of the outer faces) or Tangent to bend (tangent to the bend, parallel to the new flange). This decides what "25 mm tall" means.
6. Choose Bend position: Inside (inside the boundary of the outermost faces), Outside (outside the boundary of the innermost faces), Adjacent (the bend starts at the selected edge) or Tangent (the bend is tangent to the selected edge).
7. Optionally Flip the flange 180 degrees, enable Miter corners where adjacent flanges would overlap, and toggle Override rules if this one flange needs its own radius or relief.
8. Click OK.

Options reference#

Tips and pitfalls#

Tip: For a box, dimension flanges "Outer faces" with "Bend position: Inside". The overall dimensions then match a drawing that quotes the outside size.

Tip: Use Two offsets to make a tab that stops short of a corner, which is the cleanest way to avoid cross-bend interference with a neighbouring wall.

Warning: A flange that is too short for the die cannot be bent. As a rule of thumb the flange height must be at least about 4 times the thickness plus the bend radius (for example 4 x 2 + 2 = 10 mm for 2 mm material with a 2 mm radius); ask the shop for their minimum.

Warning: If To object fails, check that the target is planar and parallel to the selected edge, and that only one edge is selected.

Tip: Select several edges at once for identical flanges; they are one feature in the timeline and one edit changes all.

Height datum and bend position: working through the numbers#

These two options are the ones people get wrong, because they change what "height" means. Take a 100 x 60 mm base flange in 2 mm material with a 2 mm inside radius, and add a 90 degree edge flange of height 30 mm on the 100 mm edge.

If the drawing quotes the outside height of a box as 30 mm, choose Outer faces. If the shop wants the straight flange length for die clearance, choose Tangent to bend. The visible wall height is the same part either way; what changes is how the number is defined, so decide once and keep it consistent across all flanges.

Bend position then decides which way the bend sits relative to the base flange envelope:

• Inside keeps the bend within the base plate boundary, so the overall box footprint equals the base flange size. This is the usual choice for boxes quoted by outside size.
• Outside places the bend outside the boundary, so the overall size grows by the radius plus thickness on each side. Use it when the base is an inside dimension.
• Adjacent starts the bend exactly at the selected edge, and Tangent makes the bend tangent to the edge, which suits flanges that must continue a flat plane.

Worked example: a box that must be 100 x 60 mm outside#

Make the base flange 100 x 60 mm, add four edge flanges with Outer faces and Bend position Inside, and check with Measure that the outside is 100 x 60 mm. If you had used Outside, the overall would be 100 + 2 x 4 = 108 mm by 68 mm for 2 mm material and 2 mm radius. Seeing the difference in the preview before you click OK saves a rebuild.

Width types, one at a time#

For an edge flange, the width type is set per selected edge.

• Full edge runs the length of the edge. It is the default and gives a wall.
• Symmetric needs one Distance and centres the flange on the edge midpoint. A 30 mm Symmetric flange on a 100 mm edge leaves 35 mm on each side.
• Two sides takes Distance 1 and Distance 2 from the midpoint, for off-centre tabs.
• Two offsets takes Reference 1 with Offset 1 and Reference 2 with Offset 2, so the flange is placed between two features, such as two holes or two other flanges. Use it to hold a tab 10 mm clear of each corner.

Combine width types with Miter corners carefully: a short tab that does not reach the corner has nothing to miter with. Where tabs of different width meet a wall, add a relief at the end in the rule.

Edge flange to an angle other than 90 degrees#

Any angle may be typed. Angles below 90 produce open V shapes; above 90, closing returns and hems. A 135 degree flange on a plate edge makes a stiffening lip. Remember that a press brake can form a hem only in two steps (an acute bend then flattening), so check that your shop offers it. Over 150 degrees the bend may fail in Fusion or be rejected by the shop; consider a dedicated hem if one is available in your build.

Common failures and fixes#

Practice exercise#

Prove to yourself what the height datum and bend position options do.

1. Create a 2 mm steel rule with a 2 mm inside radius and K-factor 0.35. Make a 120 x 80 mm base flange.
2. Add one edge flange on the long edge, 30 mm, 90 degrees, Height datum Outer faces, Bend position Inside. Measure the outside height from the bottom of the base.
3. Edit the flange to Tangent to bend. Record the new height. Then edit to Inner faces and record again.
4. Set the datum back to Outer faces and change Bend position to Outside. Measure the overall footprint and compare it with the 120 x 80 mm base.
5. Add the other three edge flanges with Outer faces and Inside, tick Miter corners, and check the outside dimensions of the tray: they should be 120 x 80 mm.
6. Change one flange to 100 degrees and observe the preview. Then use Two offsets on another wall to leave 15 mm clear at each end.
7. Create the flat pattern and check for corner gaps.

Expected result: three different measured heights for the same typed value (the difference between datums is a few millimetres), an overall footprint that grows by 8 mm per direction under Outside, and a mitred tray with small corner gaps. Record all measured values in a table.

Related#

• Contour flange
• Sheet metal rules
• Bend and corner treatments
• Unfold and refold