The ECO2il project, carried out from 1 June 2019 to 31 May 2022 and published on 15 March 2023, set out to create environmentally sustainable lubricants for machining operations such as turning, milling and drilling. The work was organised into four main work packages. In the first package the team defined reference processes and criteria for the three machining operations, selecting suitable materials and establishing experimental conditions. The second package focused on the selection and assessment of base oils, evaluating their sustainability through a set of ecological indicators that cover climate protection, ecotoxicity, resource efficiency, renewable resource use, eutrophication, acidification, transport distance, renewable raw‑material share, biodegradability, water‑hazard class, yield, natural‑area consumption, primary‑energy demand, global‑warming potential and eutrophication potential. The indicators were scored on a scale from +2 (highly favourable) to –2 (unfavourable), allowing a clear comparison with conventional mineral‑based lubricants. The third package addressed the choice and evaluation of additives, optimizing additive‑laden oils for milling and turning and testing their mixing and sprayability, as well as their performance in cold‑water cooling systems. The fourth package validated the developed bio‑based lubricants in the reference processes. A comprehensive evaluation matrix was applied, and a series of experimental tests were performed: milling with external cooling, turning tests, drilling tests at Gühring, and finishing turning at Schaeffler. The results showed that the bio‑based lubricants matched or exceeded the performance of conventional lubricants while delivering significant reductions in several environmental indicators, such as lower global‑warming potential, reduced eutrophication potential and improved biodegradability. The project also established a pathway for certification under the EU Ecolabel, demonstrating that the developed lubricants meet stringent environmental criteria.
Collaboration was central to the project’s success. The partners were Gühring KG, Rhenus Lub GmbH & Co KG and Schaeffler Technologies AG & Co KG. Each partner contributed specific expertise: Gühring supplied machining equipment and expertise in drilling, Rhenus Lub provided knowledge of lubrication systems and supply chain considerations, and Schaeffler supplied finishing‑turning equipment and process optimisation. The project was funded under German federal and European Union programmes, with funding codes ranging from 22005218 to 22028518. The coordinated effort of the partners over the three‑year period enabled the systematic development, testing and validation of the bio‑based lubricants, culminating in a report that documents both the technical achievements and the collaborative framework that made them possible.