The Z map has been widely used to simulate cutting operation because of its simplicity, fast computation time and robustness compared to a solid model. This paper presents an improved optimization system based on exact simulation of cutter immersion volume using the enhanced Z map model. By adopting the basic idea of anti-aliasing theory of computer graphics, the accuracy and robustness of geometric Boolean operation using Z map model can be significantly improved at approximately equal computation time. The proposed algorithm can instantaneously calculate cutting force using force buffer algorithm, and optimize cutting operation subject to several constraints on cutting condition.