Download PDFOpen PDF in browserAdhesion-Free Mold-Stamping of Meniscus Inorganic Glass Lens Using N-Doped SiC Dies8 pages•Published: August 6, 2026AbstractMost of optical inorganic glass lenses and elements have been fabricated by mold-stamping above their glass-transition temperature (Tg) in industries. In this process, these glass melts above Tg, visco-elastically deformed, filled into the die cavity, and were net-shaped to the tailored optical lens and element. In this step, these melts had a risk of adhesive wear or galling to the die surface during their significantly large surface area extension under the stressed contact state to die surfaces. Hence, the die materials must have autonomous mechanism to be free from galling in addition to high heat resistance. In the cooling step across Tg, their shape and optical properties were fixed by thermal loading program. The deviation of temperature distribution in transients increased the risk of cracking and enhanced the thermal stresses. Hence, the die materials must have high thermal conductivity and toughness. As studied in [1-2], the nitrogen-doped SiC (Silicon Carbide) coating with the mm-ordered thickness, had 6H-structured microstructure with the carbon structured grain boundaries at the vicinity of contact surface. Due to its high heat-resistance and thermal conductivity, it had much less risk of thermal deviations to cause the stress-induced cracking during cooling and quenching steps toward galling-free mold-stamping.In the present paper, the tandem-type, CNC (Computer Numerical Control) mold stamper was utilized to describe the galling-free and crack-less procedure in fabrication of the meniscus optical lenses. The boron-silicate and high-Tg glass preforms were employed as a work. SEM（Scanning Electron Microscopy）- EDS (Electron Dispersive X-ray Spectroscopy) and Raman spectroscopy were utilized to describe the in-situ formation of amorphous carbon tribofilm on the contact interface of N-doped SiC die and to analyze the carbon sp1-structuring along the grain boundaries of SiC die. The surface profilometer was used to investigate the dimensional accuracy of mold-stamped meniscus lens for practical demonstration on the usefulness of present approach. Keyphrases: galling free stamping, in situ amorphous carbon film formation, inorganic glass works, n doped sic dies In: Numpon Mahayotsanun (editor). Proceedings of The 11th International Conference on Tribology in Manufacturing Processes & Advanced Surface Engineering, vol 4, pages 1-8.
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