Abstract
The article presents a comprehensive review of current methodologies for monitoring the condition of metalworking fluids (MWFs) employed in machining operations. Emphasis is placed on physico-chemical, biological, and electrochemical assessment techniques, including the measurement of pH levels, concentration, contamination, microbial activity, electrical conductivity, and optical characteristics. Particular attention is devoted to the integration of automated and sensor-based monitoring systems capable of real-time data acquisition and analysis. The advantages, limitations, and applicability of these methods within the framework of modern digital and automated manufacturing environments are critically examined. The findings underscore the importance of adopting a multidisciplinary and systematic approach to MWF quality control in order to enhance process efficiency, ensure production stability, and extend the service life of fluids.