A novel boundary-first mapping method for jewelry CNC machining toolpath generation

With the popularity of 3D scanning and measuring techniques, the advanced jewelry manufacturing enterprises tend to machine directly on the raw blanks that contain varying degrees of shape errors, which necessitates an effective mapping method to transform the 2D paths onto the 3D-scanned mesh surface. To address the issue, this paper put forward a novel boundary-first mapping method for jewelry computer numerical control (CNC) machining toolpath generation. The proposed method first implements the conform mapping via the Boundary First Flattening (BFF) algorithm, and then flattens the mesh surface onto a fixed 2D region for design. At last, the 3D toolpaths are derived by inversely mapping the designed 2D paths. The effectiveness of the proposed method is validated through simulations results, indicating that the generated 3D toolpaths retain satisfactory shapes which are in good alignment with those in the 2D design region, remaining largely unaffected by surface shape deformations.