The invention relates to a method for acquiring the optimized parameters of a machining operation in the application of COM methodology, comprising: providing a plurality of readings indicative of the specific cutting energy (Kc) during an equal plurality of tests carried out with an imposed value, that is different from one test to another by at least one variable representative of the cutting operations, one of said variables being the cutting speed (Vc) and another being the advance rate (f); next determining a range of values of each of said variables including the optimal value for said variable obtained by means of processing the results for carrying out the machining operation; characterized in that a specific program (10a) of the digital control (7) is used for obtaining a continuous variation of the values of the variable during a single machining pass for a test, and in that the data read are formed during said single pass by the different values of the torque current (Iq) of the motor of the machine pin from which the corresponding values of (Kc) are derived by means of computational processing.