Bend Intellishape Properties

Sheet Metal Bend IntelliShapes have three properties sheets: General, Bend and Reliefs, which are accessed by right clicking on a bend IntelliShape and selecting IntelliShape Properties. Since the options available on the General properties sheets are identical for all IntelliShapes, this section only covers the options on the Bend and Relief properties sheets.

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Bend with Stock vs. Standard Bend

Bend with stock adds a seperate flat stock piece to the bend. This stock piece has a 2D cross section which can be edited, and remains a seperate entity to the Bend shape. Bends with stock cannot be used with the Miter tool, where as standard bends can.

A standard bend still has a flat section, but it is contained in the Bend shape, and therefore doesn't have a separate cross section. It can be resized to 0 length to be removed from the Bend, which can be useful in some cases. Standard Bends can be used with the Miter tool, but are sometimes less customizable than Bends with Stock.

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Bend Types (Bend, In Bend, Out Bend)

Bend Bends will extend away from the stock at the full distance of the bend radius.

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In Bends cut into the sheet metal sheet to use the internal dimensions of the stock, as if there is no bend radius at all.

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Out Bends cut into the sheet metal sheet, to match the Outside Dimensions (out bend).

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Bend Properties

Radius.  Offers options for specifying radius to be used for the bend.‍

• Use minimum bend radius of part.  Select this option to use the minimum bend radius specified for the part. If this option is selected, the following two options are not available.
• Inside Radius:  This field is only available if "Use minimum bend radius of part" is not selected. Use this function to specify a precise inside radius for the bend.
  
• Outside Radius.  This field is only available if "Use minimum bend radius of part" is not selected. Use this function to specify a precise outside radius for the bend.
  

First Bend Stock

• Display handle.  Select this option to display the shape handle on the first bend stock portion of the bend shape.
• Length.  Enter a value in this field to specify the length of the first bend stock portion.

Second Bend Stock

• Display handle.  Select this option to display the shape handle on the second bend stock portion of the bend shape.
• Length.  Enter a value in this field to specify the length of the second bend stock portion.

Bend Allowance.  Offers options for method of determining bend allowance for the bend shape.

• Use k-factor formula.  Select this option to use the k-factor formula in calculating bend allowance.  
• Show rule.  Select this option to display the Bend Allowance Calculation dialog box.
• Use k-factor of part.  Select this option to use the k-factor specified for the part in determining bend allowance.
• k-factor.  This field is only active if the previous option is not selected. Use this function to specify a precise k-factor for the bend allowance.
• Specify Custom Value.  Select this option to specify the unfolded length of the bend to be used for determining bend allowance.‍
• Unfolded length.  This field is only active if the previous option is selected. Enter a precise value for the unfolded length of the bend shape.‍
• Specify bend deduction. By definition, the bend deduction is the difference between the bend allowance and twice the outside setback.‍
• Unfolded Bend Line Offset. Offset the bend line by a positive or negative value.‍
• Start and End Offset. Set the extension line offset from the start and end points of the bend lines.

Width  Use these two options to define the width of the bend shape relative to the point on the stock at which it was placed.‍

• Above.  Enter a value in this field to specify the width of the selected bend above the point on the stock at which it was placed.
• Below.  Enter a value in this field to specify the width of the selected bend below the point on the stock at which it was placed.

Show Formulas.  Check this option to view/create formulas that produce values on this properties sheet.

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Relief Properties

Bend Reliefs.  These options define the parameters to be used for the bend reliefs on the selected bend shape.‍

• ‍Relief type:  Use this option to specify the type of relief to be used on the bend shape, either: Rectangular or Rounded.
• Width/Depth.  These fields are used to specify the precise width and depth to be used for the bend relief on the selected shape.

Corner reliefs.  These options are used to define the parameters to be used for corner reliefs on both sides of a bend. The Left and Right corner relief images update to reflect the specified options.

• Square Relief Type.  Select the appropriate radio button to specify a square corner relief for the left and/or right side of the bend.
• Closed Relief Type.  Select the appropriate radio button to specify a closed corner relief for the left and/or right side of the bend.
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• Orientation Top. If closed corner reliefs are specified, select the appropriate radio button to specify that the orientation be based on the top of the corner relief for the left and/or right side of the bend.
• Orientation Bottom. If closed corner reliefs are specified, select the appropriate radio button to specify that the orientation is based on the bottom of the corner relief for the left and/or right side of the bend.
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• Depth. Specify the value for the depth of the corner relief. The value can be a positive or negative depending on the orientation.

Show Formulas. Check this option to view/create formulas that produce values on this properties sheet.

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Bend Allowance Calculation

Bend allowance is calculated based on bend angle, material thickness, and inside radius.  If a sheet material is uniform in section and its elastic limit is not exceeded, then its neutral plane (or axis in 2D) coincides with the centerline of the material.  However, when the bending forces exceed the elastic limit, the neutral plane moves towards the inner surface of the bend.

Typically, the plane repositions at a distance of one-third to one-half the thickness of the material.  The value that describes this repositioning of the neutral plane is called the "k-factor."  [Note:  This is the ANSI (American National Standard Institute) definition for k-factor.]

Bend Allowance (BA) is calculated using the general equation: B.A. = [Theta x (InsideRad + k-factor x stock Thickness)] where Theta is the complementary angle of the bend (measured on the outer surface of the bend).

For cases where bend angle is greater than 174 degrees and the inside bend radius is less than half the sheet thickness, we consider the bend to be a Hem or Dutch bend (Benson, 1997).  To calculate the bend allowance for hems (hem allowance), we use Table 7-2 from (Suchy, 1988).

For material with sheet thickness outside the range of the hem allowance table, the normal ANSI bend allowance formula will apply.