Toolpath Fillets reference

Avoid sharp corners in 3D finishing toolpaths.

Fusion provides a toolpath filleting function that is useful for avoiding sharp corners in 3D finishing toolpaths. With fillets applied, sharp turns in the toolpath can be reduced so that the CNC control can maintain a higher feedrate and/or prevent marks on the machined part.

fillets dialog section

The Fillets section and Fillet Radius parameter are located on the Passes tab between the Stock to Leave and Smoothing sections

The following images show an example of a Parallel finishing toolpath using a 10 mm ball end mill.

fillets disabled diagram

Fillets disabled

fillets enabled diagram

Fillets enabled. Fillet radius is 10 mm - twice the tool radius

fillets disabled with fillet geometry applied diagram

Fillets disabled, but the model has fillet geometry features applied

Enabling fillets on a Parallel finishing toolpath primarily affects corners perpendicular to passes.

parallel toolpath without fillets diagram

Parallel toolpath without toolpath fillets

parallel toolpath with 4mm fillet radius diagram

Parallel toolpath with a toolpath fillet radius of 4 mm

Similarly, for a Contour finishing operation, the fillets in vertical corners:

contour toolpath without fillets diagram

Contour toolpath without toolpath fillets*

contour toolpath with 4mm fillet radius diagram

Contour toolpath with a toolpath fillet radius of 4 mm

Important: When using toolpath filleting, more stock will be left than specified by the Radial Stock to Leave and Axial Stock to Leave settings. You should therefore keep the fillet radius fairly small and remember to machine the leftover stock with a following operation.