An approach to optimize the tilt angle of indexable table for nonorthogonal four-axis milling of impeller

In order to improve the capacity and quality of four-axis machining complex surface impeller, a new method is proposed for optimizing the tilt angle of wedge-shaped indexable table in this paper. The main idea of this method is that through the establishment of tool axis optimization model which relates to the tilt angle, the optimal tilt angle can be obtained under the condition of the tool axis changes smoothly. Firstly, the constraint relationship between the tilt angle and the tool axis is analyzed in terms of the actual machine structure limits of four-axis machine. Secondly, the feasible region of tool axis is calculated by the planar mapping method, and then according to the smoothness principle, the tool axis optimization model which relates to the tilt angle is established. Finally, the optimal tilt angle is calculated by solving the tool axis optimization model, and a practical example of impeller milling is conducted on a four-axis machine when the indexable table is fixed at the optimal tilt angle. Experimental result demonstrates that the proposed method is correct and effective.