Abstract: In this paper,cutter path of NC machining of pockets has been generated through re-sults oftwo easier cases of machining,i.e., machining of surface and machining of intersection of surfaces.A concept of Boundary Pocket of Cutter Locations(BPCL) has been presented to de-velop a simple and effective pocket machining algorthm,in which cutter cen ter locations are gained by clipping cutter path of machining of bottom surfaces with BPCL,and cutter axis vectors by a process of spatial mesh generation on the cap of BPCL. Conditions of spatial mesh generation to approach uncollided and evenly varied cutter axes have been presented and proved.This paper has also presented methods of verification and modification of cutter locations.The algorithm is capable ofhandling pockets bounded by sculptured surfaces wherever at the bottom or on the side ofthe pockets,with any number ofislands in 5-axes NC machining, and has been realized on the basis of NPU-CAD / CAM system(which is developed in authors′research center),and was successfully used in NC machining ofa vessel impeller,

Key words: cutters, position(location), computer aided manufacturing, milling(machining)