Investigation of Surface Integrity Induced by Ultra-Precision Grinding and Scratching of Glassy Carbon

Autor: Kirk Jahnel, Robert Michels, Dennis Patrick Wilhelm, Tim Grunwald, Thomas Bergs
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Micromachines, Vol 14, Iss 12, p 2240 (2023)
Druh dokumentu: article
ISSN: 2072-666X
DOI: 10.3390/mi14122240
Popis: Glassy carbon provides material characteristics that make it a promising candidate for use as a mould material in precision glass moulding. However, to effectively utilize glassy carbon, a thorough investigation into the machining of high-precision optical surfaces is necessary, which has not been thoroughly investigated. This research analyses the process of material removal and its resulting surface integrity through the use of nano-scratching and ultra-precision grinding. The nano-scratching process begins with ductile plastic deformation, then progresses with funnel-shaped breakouts in the contact zone, and finally concludes with brittle conchoidal breakouts when the cutting depth is increased. The influence of process factors and tool-related parameters resulting from grinding has discernible impacts on the ultimate surface roughness and topography. Enhancing the cutting speed during cross-axis kinematic grinding results in improved surface roughness. Increasing the size of diamond grains and feed rates leads to an increase in surface roughness. An achievable surface roughness of Ra < 5 nm together with ductile-regime grinding behaviour meet optical standards, which makes ultra-precision grinding a suitable process for optical surface generation.
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