B axis rotating machining of microstructured optical molds with rotational symmetry based on ultra-precision cutting

A B axis rotating machining process based on ultra- precision cutting was developed to prevent burrs, sharp corner defects and surface scratches when machining microstructured optical molds with rotational symmetry. The form accuracy and surface quality of the molds were mainly influenced by the machining path, cutting speed, B axis rotating speed and cutting depth. Tests of these factors were used to optimize the cutting trajectory planning and machining parameters. Two microstructured molds were constructed with no sharp corner defects and no surface scratches, dimensional accuracies of 1.4 μm and surface roughnesses better than 14 nm. The results show the feasibility of the B axis rotating machining process for cutting microstructured optical molds with rotational symmetry.