Original Date: 11/03/1996
Revision Date: 01/18/2007
Information : Single-Point Diamond Turning of Optics
One main objective for the Oak Ridge Y-12 Plant Optics Manufacturing Operational Development and Integration Laboratory (MODIL) is the development and proofing of advanced manufacturing technologies for optics manufacturing. Single point diamond turning is a common optics manufacturing process which can achieve final design requirements exhibiting proper geometric forms with nanometer smoothness characteristics. To develop improvements in this manufacturing technology, the Optics MODIL has selected a Rank Pneumo Nanoform 600 single-point diamond turning machine that produces surface finishes in the 500 nanometer range. Because of the delicate vibration and thermal sensitivity nature of this precision process, vibration isolation is incorporated into the machine design and the machine mounting foundation pad. A positive air pressure curtain, constructed of thin polyvinyl strips hung from the ceiling, is maintained around the immediate perimeter of the machine to provide a thermal barrier to guard against large atmospheric temperature gradients that may affect the final surface finish.
To machine secondary eccentric non-linear features within a parabolic optic part, the laboratory is piloting a prototype Fast Tool Servomechanism developed by the University of North Carolina. This technology provides rapid CNC-controlled Z-axis tool movement necessary to machine eccentric features without secondary setups and fixturing. With these added features, the single-point diamond turning lathe can machine finished part quality for complex optical forms.
Y-12 planned enhancements to the single point diamond turning process include outfitting the machine with spectrographic metrology equipment (OmniscatR model) provided by Brealt Research Organization. Edge quality and profile description of the single-crystal natural diamond cutting tool is also an area for continuous improvement to these manufacturing processes. Through the integrated use of LVDT non-contact sensors and a PC with National Instruments LAB VIEW development software, a complete graphical representation of the diamond tip surface can be mapped and analyzed. Irregularities within the edge quality will dictate to the machine tool operator the proper orientation of the diamond tip to achieve optimal quality features.
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