Study of the operating efficiency of hybrid metalworking-fluid blends in centralized systems during machining of aluminum-alloy workpieces in mass production

Metalworking fluids (MWFs) are a proven technological means of ensuring high efficiency in machining operations. In recent years, synthetic and semi-synthetic MWFs have been successfully adopted in mechanical engineering. In some cases, hybrid MWFs–mixtures of synthetic and semi-synthetic fluids–are used. This article examines machining scenarios for aluminum-alloy workpieces when hybrid MWFs are employed under mass-production conditions. The aim of the study was to identify the features of machining aluminum-alloy workpieces in a medium of hybrid high-concentration MWFs from the standpoint of resource conservation and environmental performance. The research methodology was based on evaluating time- and workspace-dependent losses of MWF volume within the nested system “MWF – centralized support subsystem – technological system,” and on identifying relationships between technological performance indicators and loss indicators, i.e., the “entropy” of MWFs. The study established the relationships between design-technological and entropic indicators and provided estimates of the entropic magnitudes. The composition of MWF losses is characterized as interrelated distributed inevitable losses (Type-I entropy) and instantaneous full discharges of volume from centralized systems (Type-II entropy). In machining aluminum-alloy workpieces, Type-I entropy accounts for 0.67–0.74 of the total MWF entropy in the given technological situation. The number of replacements per year varies within 0.7–2.0, and the operating life is 0.5–1.3 years. This variation leads to combined annual losses of about 1,300 m³/yr. The paper outlines the possibility of a radical reduction in the entropy of synthetic MWFs.