Creating Chordal Fillets  

The Chordal Fillet command is used to control the width of the fillet (distance between the 2 rolling edges) which is also called as chordal length.


The command allows you to define the two types of variation to the chordal fillet:

  • Cubic
  • Linear
Open the Chordal_Fillet.CATPart document.
  • Click Chordal Fillet .
    The Chordal Fillet Definition dialog box is displayed. Default options let you define a Cubic variation of the Chordal Fillet.

  • For Part Design workbench, Click Chordal Fillet .

    For Generative Shape Design workbench, Click Chordal Fillet .

    The Support and Extremities fields are not seen in the Part Design workbench.

  • Select the edge to be filleted. You can define chordal fillets on closed edges.
    The application detects both vertices and displays two identical chordal length.

  • Double-click on the chordal length to access the Parameter Definition dialog box. For example, enter 50mm.

  • Click the icon at the right of the Points field. Select Variable_Plane in the geometry.

  • You can define fillet with variable width by specifying intermediate points.

  • Double-click Variable_Plane chordal length. For example, enter 20mm.

  • Select OK in Chordal Fillet Definition dialog box.

  • You can select the Conic parameter check box. This check box allows you to vary the section of the fillet.
    For a parameter comprised between or equal to:
    • 0.5, the resulting curve is a parabola.
    • 0 < parameter < 0.5, the resulting curve is an arc of an ellipse.
    • 0.5 < parameter < 1, the resulting curve is a hyperbola.
    • Conical fillets do not handle twist configurations. If a twist is detected, the fillet operation fails.

    • If the fillet surface curvature is lower than the support curvature, fillet surface relimitation may fail. In such cases, the conic parameter has to be decreased.

    Limiting Elements

  • To edit this fillet, double-click EdgeFillet.1 in the specification tree. Click the More button to access the Limiting element option.

  • Click the icon of Limiting element(s) field, then select Limit_Plane in the geometry.

  • Click this arrow to reverse the direction and therefore specify the portion of material that will be kept.

  • Click OK. The variable radius fillet is trimmed to Limit_Plane. The final part looks like this:

    • The chord length is measured using the U isoparams (circular arcs).

    • The fillet surface respects the specified chord length. The chord length is measured using the circular arcs.

    • Some faces are created to correct the twists. In such cases corresponding warning is displayed. Such untwist surface in general does not satisfy the chord length constraint.