A challenging study on compatibility or incompatibility of vegetable-based lubricant with human health

Abstract

More than 70% of industrial lubricant waste releases into nature after a period of utilization without any ltration stage. Knowing environmental concerns and increasing regulations over pollution, the request to use risk-free lubricant is irrefutable. One of these lubricants is vegetable-based cutting uid (VBCF), which has recently attracted attention. The present work has tried to study the compatibility or incompatibility of VBCF with human health and provide a method for eliminating or reducing their potential risks. To achieve this goal, a study on one of the most known, destructive, and accessible microbes (Pseudomonas) in the workshop environment was performed. The results showed that Pseudomonas could multiply in solid and liquid mediums, and its colonies could quickly propagate in VBCF. Therefore, as a signi cant achievement in this study, unreinforced VBCF is not a suitable selection from a health point of view. Although these cutting uids are introduced as a compatible lubricant with humans and the environment, bacteria and mold can multiply swiftly without apparent alterations. It was also observed that using nanoparticles like copper-oxide with a speci c volume fraction (0.4%) could ght with the bio lm of Pseudomonas to destroy the colonies at the initial time of their formation. Scanning Electron Microscope (SEM) images and Energy-Dispersive X-ray spectroscopy (EDX) analysis also studied the machinability attributes. The machining tests indicated that the nano uid also greatly impacts the control of tool wear mechanisms and surface quality in A286 superalloy machining. 1-IntroductionSigni cant heat is produced during the machining of superalloys and other di cult-to-cut materials, drastically decreasing the tool life [1, 2]. Therefore, cutting uid (CF) is utilized to reduce the cutting temperature during the process [3, 4]. In general, cutting uid is applied to improve the e ciency and performance of cutting operations [5]. The main advantages of cutting uid application are reducing the heat, increasing tool life, improving surface nish, preventing adhered-chip formation on the tool face (especially in alloys of which adhesive wear is the dominant mechanism), and facilitating chip removal of the cutting area [6]. Though different CFs utilized in the machining industry, mineral-based cutting uids (MBCFs-approximately 85% of used oil) are the most widely used ones. Some scientists reported the worldwide consumption of 2.4 million tons of different cutting uids per year [7, 8]. Besides, the annual consumption of MBCFs in the European Union is around 320 thousand tons. Furthermore, more than twothirds of the used oils deliver to nature without a ltration process [9]. However, the use of cutting uids creates some di culties and limitations, including environmental issues, operator health problems, as well as high costs (purchase and maintenance) due to unstable crude oil derivatives (approximately 17% of the total cost of cutting processes) [10,11].In practice, all CFs utilized in machining industries are...