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Proceedings Paper

Influence of coolant on ductile mode processing of binderless nanocrystalline tungsten carbide through ultraprecision diamond turning
Author(s): Marius Doetz; Olaf Dambon; Fritz Klocke; Oliver Fähnle
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Paper Abstract

Molds made of tungsten carbide are typically used for the replicative mass production of glass lenses by precision glass molding. Consequently an ultra-precision grinding process with a subsequent fresh-feed polishing operation is conventionally applied. These processes are time consuming and have a relatively low reproducibility. An alternative manufacturing technology, with a high predictability and efficiency, which additionally allows a higher geometrical flexibility, is the single point diamond turning technique (SPDT). However, the extreme hardness and the chemical properties of tungsten carbide lead to significant tool wear and therefore the impossibility of machining the work pieces in an economical way. One approach to enlarge the tool life is to affect the contact zone between tool and work piece by the use of special cutting fluids. This publication emphasizes on the most recent investigations and results in direct machining of nano-grained tungsten carbide with mono crystal diamonds under the influence of various kinds of cutting fluids. Therefore basic ruling experiments on binderless nano grained tungsten carbide were performed, where the tool performed a linear movement with a steadily increasing depth of cut. As the ductile cutting mechanism is a prerequisite for the optical manufacturing of tungsten carbide these experiments serve the purpose for establish the influence of different cutting fluid characteristics on the cutting performance of mono crystal diamonds. Eventually it is shown that by adjusting the coolant fluid it is possible to significantly shift the transition point from ductile to brittle removal to larger depths of cut eventually enabling a SPDT of binderless tungsten carbide molds.

Paper Details

Date Published: 27 August 2015
PDF: 7 pages
Proc. SPIE 9575, Optical Manufacturing and Testing XI, 95750R (27 August 2015); doi: 10.1117/12.2186989
Show Author Affiliations
Marius Doetz, Fraunhofer-Institut für Produktionstechnologie (Germany)
Olaf Dambon, Fraunhofer-Institut für Produktionstechnologie (Germany)
Fritz Klocke, Fraunhofer-Institut für Produktionstechnologie (Germany)
Oliver Fähnle, Fisba AG (Switzerland)

Published in SPIE Proceedings Vol. 9575:
Optical Manufacturing and Testing XI
Oliver W. Fähnle; Ray Williamson; Dae Wook Kim, Editor(s)

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