Optimization of grinding processes using CO2 and MQL strategies for Zerodur: a comparative study with flood cooling

Brittle-hard materials such as Zerodur, quartz glass, silicon nitride, and silicon carbide are widely used in industries like aerospace, semiconductors, metrology, and energy technology due to their unique properties, particularly low thermal expansion. Components made from these materials often feature complex geometries—such as pockets and hollow structures—that demand precise grinding processes for their fabrication. For instance, lightweight mirror backs in optics are ground to achieve optimal weight-to-stiffness ratios, with up to 90% weight reduction achieved through thin-walled designs. Similarly, photolithography components in semiconductor fabrication require high surface quality and dimensional accuracy. While flood cooling is traditionally used to manage grinding heat, it is both resource- and energy-intensive. This study explores cryogenic minimum quantity lubrication (cMQL) as a sustainable alternative. Under optimized laboratory conditions—using new tools, fine-tuned parameters, and precise nozzle positioning—grinding forces were reduced while maintaining acceptable surface roughness. These findings demonstrate the potential of cMQL to enhance sustainability in precision grinding. By addressing the evaluation of tooling under alternative cooling strategies, this research contributes to advancing both economic and ecological sustainability in the grinding of brittle-hard materials.