The present paper introduces the use of voxels embedded in an octree structure in order to numerically simulate manufacturing processes. In particular, micro electrical discharge machining (µEDM) is used here as a case study. The involved elements (tool and workpiece) are modelized in a volumetric manner using voxels and the process is simulated on a step-by step basis. Comparisons using the Hausdorff metric with experimental results are included and discussed.