Ultra-precision direct diamond shaping of functional micro features

Abstract

• Direct Diamond Shaping is presented as a novel machining method, producing unique features using the UPM. • Rotary and linear features can now be machined continuously with a turning tool. • 2D and 3D complex functional micro features can now be realized using the Virtual Rotating Tool Shaping algorithm. • Successfully machined a Bi-focal segmented Fresnel lens by Direct Diamond Shaping without the need for assembly. • Successfully machined a serpentine microfluidic channel with linear and rotary features by Direct Diamond Shaping. • Comprehensive geometrical analysis on tool limitations during shaping of channels is presented. As technological components continue to utilize space effectively within devices without compromise to their operational efficiency, the relevance of accurate and precise parts with good tolerances and surface finishing has shot to prominence. Ultra-Precision Machining (UPM) technology has constantly risen to the challenge by realizing components with superior geometrical accuracies and mirror-like surface finishes, much of which are required in the optical industry. However, conventional diamond shaping processes are usually limited to rotary symmetric components or linear gratings. Thus, the developed Virtual Rotating Tool Shaping (VRTS) addresses these issues by enabling the UPM to fabricate non-rotary symmetric, intricate and freeform elements by Direct Diamond Shaping (DDS). VRTS synchronizes the linear and rotational motions of the ultra-precision machine to constantly align the tool with the cutting direction, while compensating in the linear axes for the run-off. As such, DDS can now achieve a combination of linear and rotary features by planing. In this paper, the developed DDS technique is presented with experimental verifications of the algorithm on a segmented bi-focal Fresnel lens and a serpentine micro-channel, followed by the corresponding analyses.