The CryoEfficiency project, funded under the KMU‑innovativ programme (grant 033RK096A), ran from 1 August 2021 to 31 December 2023 and aimed to close the resource‑efficiency gap in machining high‑value cobalt‑ and nickel‑based alloys. These alloys are critical for wear‑resistant, high‑temperature and corrosive applications, yet their machining is highly material‑intensive: up to 80 % of the workpiece volume can be removed as chips. Conventional machining uses emulsified cutting fluids that coat the chips with carbon, preventing their reuse and breaking the closed‑loop supply chain. CryoEfficiency replaced this strategy with a dry, cryogenic cooling system that uses liquid carbon dioxide (CO₂) to keep the cutting zone below –80 °C. The low temperature suppresses tool wear, improves surface finish, and, crucially, leaves the chips uncontaminated so they can be directly reused in subsequent casting or machining steps.

The technical work was organised into four work packages. The first package delivered a retrofit CO₂ cooling unit that can be mounted on existing machine tools. The unit features a single external interface, programmable temperature and pressure settings, and an automatic sealing mechanism that engages during tool changes. The second package established a closed‑loop chip handling concept that guarantees chip purity and facilitates direct recycling. The third package carried out process‑technology investigations on representative machining operations—turning, milling and grinding of cobalt‑chromium‑molybdenum and nickel‑based superalloys. These studies demonstrated that cryogenic cooling not only reduces tool wear by up to 30 % compared with conventional cooling but also improves dimensional accuracy and surface roughness by 20–30 %. The fourth package validated the complete system in a pilot environment at the West Saxony University of Applied Sciences, Zwickau (WHZ). In this setting the CO₂ unit was integrated into a laboratory machining centre, and the full process chain—from chip generation to chip recycling—was tested under industrially relevant conditions. The pilot confirmed that the system is fully compatible with existing machine tool controls, that the cooling performance is stable over extended runs, and that the chips can be reused without any additional cleaning step.

Beyond the laboratory, the project produced several peer‑reviewed publications, including a feature in Diamond Business (2024) and a technical paper in DREHTEIL + DREHMASCHINE (2024) that detail the performance gains for cobalt‑ and nickel‑based alloys. The findings have been disseminated through the WHZ’s “CO₂ machining working group”, fostering knowledge exchange between academia and industry. Discussions are underway to extend the technology to larger industrial sites, with further projects planned in collaboration with WHZ and other partners.

Collaboration was central to CryoEfficiency. acp Systems AG led the development of the CO₂ cooling unit, IPlaCon GmbH contributed process‑integration expertise, the West Saxony University of Applied Sciences provided the laboratory infrastructure and validation facilities, and Deloro Wear Solutions GmbH supplied industrial‑scale machining data and potential deployment scenarios. The consortium operated under the KMU‑innovativ umbrella, a German federal initiative that supports small and medium‑sized enterprises in developing innovative, resource‑efficient technologies. The project’s outcomes not only demonstrate a viable path to a closed‑loop supply chain for critical alloys but also establish a scalable, retrofitable cryogenic cooling solution that can be adopted across a wide range of machining industries.