Cutting forces modeling is the basis to understand the cutting process, to simulate it and, most important of all, to optimize the process parameters in order to obtain a high quality product with the minimum machining time. In order to have a reliable model to predict the tool deflection and vibration it is necessary not only to measure the mean value and the direction of the cutting force but also its time-domain behavior. The basis is to develop a cutting force model that can be applied to different cutting conditions. Many models have been proposed to obtain a reliable cutting force value, most of all define a number of cutting coefficients for a specific cutting condition and pair material-tool. The aim of this paper is the study of the influence of feed per tooth and cutting speed on the cutting coefficients in order to create a model able to predict reliably the cutting force with different process parameters. The model has been developed for the tangential cutting coefficient using aluminum 6082-T4 as test material.