Abstract
The increasing of advancements in technology achieved both in the development of new different materials and in the manufacturing technology has drastically increased the need for machining processes and accordingly the usage of cutting fluids increased. In addition, pressure from Environmental Safety and Health Agencies for all the products to be advertised more safely and without damaging the environment has also influenced the increase in the quality of the cutting fluids. The herbal based cutting fluids has been increasingly used by the engineering industry, because, moreover polluting less the environment, they cause less impairment to the operator and can deliver major progresses in the tool life, but on the other side it can be easily polluted by microorganisms, since they have a extensive variety of nutrients that enable their replica. This study assessed the machining performance of a herbal-based cutting fluid, connecting it with a mineral based fluid when turning an EN 8 grade steel with coated cemented carbide tools. Cutting forces and the growth of fungi and microbes. The cutting speed (Vc), feed rate (f) and depth of cut (ap) were ranged and the effect of these factors in the cutting forces had been confirmed. It was clear that the herbal based fluid provided lower cutting forces during the machining. Moreover, the vegetable-based presented higher development of bacteria when used in its lowest concentration (4%), while the mineral based fluid indicated the superior microbial growth in its higher concentration (12%). In most cases, the microorganism causes respiratory and skin irritation.