Deterministic fabrication of surface micro-step features using a facet diamond cutting tool

In this paper, a facet diamond cutting tool was specially designed and used to generate near-right-angle shape structures with mirror surface finish on both sides. A focused ion beam (FIB) was used to modify the tool cutting edge locally to improve its sharpness and straightness. The tool cutting performance was evaluated through a series of cutting trials on brass substrate under various cutting conditions, i.e. depths of cut (ranged from 5 μm to 20 μm ) and feedrate (ranged from 3 μm/rev to 20 μm/rev). A Taylor Hobson CCI 3000 was used to evaluate the form accuracy and surface roughness of the machined micro step features. The results show that the surface machined under the feed rate of 3 μm/rev have the best surface finish as compared with the surfaces machined under other tested feedrates. The cutting tool was futher used to generate two clydlindrical micro steps with step heights and widths being 20 × 20 μm and 15 × 15 μm respectively. Twelve micro steps of each design were continuously generated to reflect the repeatability of this method. The measurement results were analysed by MountainsMap with results showing that the designed micro step features were successfully generated on brass surface. The dimensional deviation ratio of step heights and widths are all less than 4.5%, which well demonstrated the fleasiblity of the proposed method on surface micro structuring.