Improvement of the Five Axis Milling Process on a Hexapod Machine Tool by Motion Optimization

Surmann, T.1, a; Rautenberg, J.1, b; Zabel, A.1, c

Institut für Spanende Fertigung, Universität Dortmund, Baroper Str. 301, 44227 Dortmund

a); b); c)


This paper presents an optimization strategy for the feed velocity along arbitrary NC-programs for the five-axis milling process on a hexapod machine tool. CAM-systems do not consider machine tool structures to generate tool paths. This usually leads to programmed tool movements, which are sub-optimal for parallel kinematic machines. Since the endeffector carries a great mass, which is held by the struts, it behaves like an oscillator, whenever forces act on it. In order to reduce vibrations of the machine structure, which may lead to a high surface roughness, strong accelerations of the endeffector have to be avoided. These accelerations occur due to rapid changes of feed direction and feed velocity. Especially the variation of tilt and lead angles leads to a fast movement of the endeffector. The acceleration forces can be kept low by an adjustment of the tool motion and velocity. Experiments show a significant improvement of the surface quality by the use of optimized NC-programs.


parallel kinematic machines, milling simulation, machine tool vibration


In: Parallel Kinematic Machines in Research and Practice, The 5th Chemnitz Parallel Kinematics Seminar, 2006, Neugebauer, R. (Hrsg.), ISBN 3-937524-40-1, S. 759-772