Precision machining of thin-walled complex aeroenginecomponents is one of the most critical requirements to achieve theirexcellent performance. Achieving the right profile for complex partsincreasingly depends on the use of CAD/CAM packages for defining optimalcutting strategies and tool paths. However, most of the existing multi-axisCNC programming key techniques are based only on the idealized geometry anddo not take into account factors such as cutting force induced part/tooldeflection. As a result, there is usually a significant deviation betweenthe planned and machined part profiles. In order to avoid these undesirableresults, such as over-cut or under-cut, production-planning engineers areconservative in the selections of process parameters. In this paper,different approaches of cutting force modeling are discussed, which includechip formation or tool-chip interface friction based analytic force modelfor orthogonal cutting, milling force model based on the cuttingcoefficients, artificial neural networks, and fuzzy-grey theory. The keyis topredict the workpiece/tool deformation, optimize the key process parameters,compensate the tool paths, and realize the physical simulation of machiningprocess.