Effects of Tool-Only Impingement with an Expanding CO2 Jet in Drilling of CFRP

The high strength-to-weight ratios of Carbon Fiber Reinforced Polymers (CFRP) have led to their extensive use in diverse engineering fields for structural applications. The structural applications require hole cutting at mass production rates, for which drilling at high cutting speeds and low operational costs is crucial. Only an efficient cooling mechanism of the drilling tool can ensure the accomplishment of the two conflicting requirements. This paper introduces a groundbreaking tool-only cryogenic cooling technique for hole-making in CFRP. Notably, this method prevents coolant interaction with the CFRP plate, unlike traditional continuous flow methods. To assess its effectiveness, we compare the novel approach to both continuous cryogenic cooling and dry cutting across key metrics like tool wear, energy consumption, productivity, hole quality, and coolant usage. Our results reveal that tool-only cryogenic cooling significantly reduces tool wear, lowers specific energy requirements, and enhances hole quality, suggesting considerable promise for efficient and high-quality CFRP hole-making.