Optimisation of workpiece setup for continuous five-axis milling: application to a five-axis BC type machining centre

When machining complex geometries on five-axis machining centres, the orientation and positioning of the workpiece in the machine workspace are generally chosen arbitrarily by the operator from the Computer-Aided Manufacturing software. Nevertheless, these two factors have considerable influence on the machining time. The present article firstly studies the choice of workpiece orientation. Relying on analysis of the machine's kinematic behaviour, orientations of the workpiece in the machine workspace are proposed minimising the overall distance travelled by the rotary axes. Secondly, choice of workpiece positioning in translation is studied. To this purpose, the work volume in five-axis machining is identified so as to avoid overshooting the machine travels when the program is executed. The optimum positioning is chosen to minimise the overall distance covered by the machine's axes of translation. Finally, the proposed method provides for a workpiece setup to be adopted that minimises the distances covered by the machine axes. This leads to reduced machining time with concomitant gains in productivity and greater respect for the cutter/workpiece relative feed rate for enhanced quality.