Meaning
Ultra-precision mechanical machining of optical surfaces using a monocrystalline diamond cutting tool achieves sub-nanometre finish and sub-micrometre form accuracy. This subtractive technique is vital for manufacturing precision optical inserts used in injection moulding. Through single point diamond turning, toolmakers create complex geometries, such as aspheric and freeform surfaces, directly in non-ferrous metals like copper, nickel, or aluminum.
The technique is limited by the chemical compatibility of the diamond tool, which cannot machine ferrous alloys without specialized cryogenic setups or tool coatings.
Machining Accuracy
High-rigidity machine tools with air-bearing spindles and laser interferometers support the diamond tip as it cuts the workpiece. In single point diamond turning, the cutting parameters are carefully controlled to maintain a continuous, ductile-regime chip formation. This control prevents brittle fracture of the workpiece, leaving a mirror-like finish that requires no subsequent polishing or hand-finishing.
Tooling Fabrication
Injection moulds for polymeric lenses require extremely smooth surfaces to avoid scattering light. Toolmakers rely on single point diamond turning to machine the mold cavities or insert faces directly. The resulting tooling yields plastic lenses with high surface fidelity, reducing assembly errors and ensuring that the final moulded parts match the designed optical prescription.
Optical Performance
Moulded plastic optics used in cameras and automotive sensors must meet strict wave-front error limits. Imperfections on the mould insert are transferred directly to the resin during the injection cycle. Employing single point diamond turning on the insert ensures that the polymer lens exhibits minimum scattering, which improves the transmission and resolution of the finished optical assembly.
