This article presents a predictive model of the kinematical behaviour during 5-axis machining. This model highlights differences between the programmed tool-path and the actual follow-up of the trajectory. Within the High Speed Machining context, kinematical limits of the couple CNC-machine-tool have to be taken into account in the model. The originality of the model is the use of the inverse-time method to coordinate machine-tool axes, whatever their nature (translation or rotation). The model reconstructs the actual relative velocity tool-surface from each axis velocity profile highlighting trajectory portions for which cutting conditions are not respected.