A specialized whirlwind milling tool and a 5-axis CNC horizontal milling machine are introduced in the paper. The equivalent normal curvature milling model is proposed for generating the tool paths in machining freeform surfaces. This new milling model can efficiently enlarge the material removal volume at the tip of the milling tool and improve the producing capacity. The machining strategy of this new model is to regulate the orientation of the whirlwind milling tool relatively to the principal directions of the workpiece surface at the point of contact, so as to create a full match with collision avoidance between the workpiece surface and the symmetric rotational surface of the milling tool. The actual examples for manufacturing the freeform surfaces are given in order to evaluate this milling scheme.