Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore
doi:10.3850/978-981-18-6021-8_OR-14-0035

Ultra-Precision Cutting of Monocrystalline Calcium Fluoride at Elevated Temperatures

Elijah Kwabena Antwi1, Kui Liu2,a, Hao Wang1 and Hu Wu2

1Department of Mechanical Engineering, National University of Singapore, 21 Lower Kent Ridge Road, 119077, Singapore

2Joining and Machining Group, Singapore Institute of Manufacturing Technology, 73 Nanyang Drive, 637662, Singapore

ABSTRACT

Brittle materials such as calcium fluoride (CaF2) have been widely employed in the manufacturing industry due to their excellent mechanical, physical, optical and electrical properties. But, manufacturing of brittle materials faces many challenges from technical to economic aspects. To obtain a smooth and damage free surface of brittle materials, traditional machining processes such as grinding, lapping and polishing are commonly used, which is very costly and extremely time consuming. Ultra-precision ductile mode cutting is thereafter an alternative way to achieve such high quality and crack free surfaces of brittle materials. Although ductile mode cutting of CaF2 is possible, it has been shown to exhibit microstructural changes which has an adverse effect on the machined surface quality. In this paper, a novel approach has been proposed for machining of CaF2 at elevated temperatures to enhance the plasticity of the substrate material thus reducing or eliminating the subsurface damage completely. To this end, a realistic molecular dynamic (MD) simulation model has been developed to provide an atomistic insight into the machining process with an appropriate choice of valid interatomic potential. Based on this model, MD simulations have been carried out to study the nanoscale cutting of single crystal CaF2 at both room temperature and elevated temperature.

Keywords: Ultra-precision cutting, Calcium fluoride, Elevated Temperature, Simulation, Cutting force



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