Tool path generation for ultra-precision machining of free-form surfaces

The generation of tool paths for ultra-precision machining is still a limiting factor in the manufacturing of parts with complex optical surfaces. In conventional machining as well as in complex five axes machining the application of CAD- and CAM-software for the generation of tool paths is state of the art. But these software solutions are not able to generate tool paths according to the high requirements of ultra-precision machining. This paper describes possible ways to generate tool paths for ultra-precision machining when the optical surface can be analytically described or when the surface data is derived from optical design software. Ultra-precision milling experiments with different tool paths have been carried out and the quality of the machined geometry has been evaluated concerning the achievable form accuracy.