Machining processes are one of the most common manufacturing processes that enable the machining of various materials, the achievement of tight tolerances and the production of complex shapes. The thermodynamic, tribological and mechanical aspects of machining process are extremely complex, which is why the machining requires the use of cooling, flushing and lubrication agents. Despite its high efficiency, the application of cutting fluids (CF) is accompanied by high costs of procurement and application in the production process. In addition, the low biodegradability of CF poses a significant risk to the environment. In order to reduce the negative impacts of conventional CF on the environment and people, there are a number of alternative cooling techniques such as: machining with minimal amounts of lubricating oil, cryogenic machining and cold compressed air machining. Despite this, none of the above techniques has seen wider application in industry due to the additional costs of procurement and application of the techniques. Thanks to its simple function and low investment costs, cold compressed air cooling using a vortex tube stands out as a technique that could replace conventional CF machining. The geometric shape of the vortex tube will be modeled with the aim of obtaining optimal efficiency using CFD analysis and existing mathematical models. The term optimal efficiency implies the maximum volume of separated particles with minimal tool wear and minimal roughness of the processed surface.