Cutting Behavior and Surface Defects in Ultra-Precision Grinding of Glassy Carbon

This study investigates the cutting behavior and surface defects in ultra-precision grinding of glassy carbon, an alternative material for mold manufacturing. The aim was to gain a comprehensive understanding of the cutting behavior to determine the suitability of ultra-precision grinding for mold manufacturing. Therefore, glassy carbon samples were ground flat and the process parameter cutting speed, cutting depth, and diamond grain size of the tool were altered. The machined surface was measured by interferometry and a scanning electron microscope to analyze the surface roughness and topography. The investigations show that ultra-precision grinding is capable of creating nearly defect-free surfaces with resulting surface roughness Sq lower than 5 nm. Additionally, it is analyzed, that the dominant cutting behavior is brittle, and the surface topography created is probably based on the fullerene-like structure from glassy carbon itself. In the case of occurring defects, the dominant breakouts are clods and resulting gaps in the surface topography. Further investigations are required to investigate the subsurface after grinding and its influence on the glass molding process.