ABSTRACT: Usually, the parameters of industrial processes are adjusted experimentally according to the results obtained after the production of a large quantity of parts, without optimal efficiency. When a Computer Numerical Control (CNC) lathe is employed, the elaboration of its program requires the determination of its machining parameters, which impacts on the efficiency of the machining processes in several aspects: time of machining cycles, relation between the useful lifeof the tools and the quantity of parts produced, power consumption, refrigerants consumption, etc. An indicator of the state of the tool is the cutting power: a new tool presents a higher cutting efficiency. A means for instantaneously measuring useful machining power throughout the production process would allow a better perception of the progression of cutting tool wear. It would also reduce the time needed to obtain the most appropriate machining parameters in order to achieve the most efficient results. Most of the research carried out to measure cutting power during machining processes involves the use of load cells, which are invasive methods that compromise the normality of production. Unlike most works found in the literature, the present work uses a non-invasive and innovative method to determine the cutting power, in real time, by monitoring the electric power demand by the machine, which facilitates and speeds up obtaining more efficient parameters in machining processes, resulting in lower consumption of electricity and inputs (inserts, cutting fluid, lubricants, etc.). A direct correspondence between the variation in the machine's electrical power demand and the effective cutting power in the CNC lathe machining process was demonstrated, resulting in an equation to express the degradation of the cutting tool. Experimental machining tests, detailed in this work, were implemented to test and validate the developed methodology.