Biointegrated cooling lubricants: Procedure model and initial testing

Abstract

Nowadays special attention is given to the sustainability in the machining industry. Especially consumables, such as cooling lubricants, can have a high environmental burden. These burdens are connected to all life cycle stages: (i) Raw material extraction, (ii) energy and resource use in processing, (iii) negative impact on working environment (iv) and disposal. Cooling lubricants, this also applies for water-miscible, predominantly contain fossils, requiring intensive processing for production and waste management. Furthermore, effects like the contamination by microorganisms either require the use of biocides that could affect the health of machine users or shorten the fluids overall lifetime. One possible approach to overcome these burdens comes from the field of biologicalisation, an emerging research effort to symbiotically link technosphere and biosphere. Microorganisms and algae hold potentials to be used as renewable raw materials for cooling lubricants due to their lubricating properties and the possibility of direct production in the factory. In studies, microorganism and algae strains have been dissolved in water and tested for their lubricating properties with promising results. However, there is a lack of further developments regarding the treatment of the negative effects by additives and the achievement of the quality standard of conventional cooling lubricants. A procedure model for the development of microbial lubricants and their implementation into process systems has been developed. Based on the functional requirements of current lubricants, additive substitutes are presented and their function-oriented compatibility is qualitatively evaluated. Additionally, the impact on the environment will be considered and discussed. Furthermore, new functions and requirements for this type of cooling lubricants will be evaluated, which results from the use of dead or living microorganisms. For this purpose, first laboratory tests have been carried out, concerning the development of the cooling lubricants, appropriate additivities and the long-term behaviour. Finally, first potential solutions for the integration and use of biointegrated cooling lubricants in industry are outlined.