NC machine tool path generation from CSG part representations

Abstract Recent improvements in geometric modelling systems have led to the need for more reliable and highly automated software for machine tool path generation. Current machining algorithms require that any part geometric information which cannot be determined from the modelling system be supplied by the user. Much geometric information is needed if the model used to represent the part is incomplete. This is the case with many conventional boundary representation systems. However, this information can easily be determined automatically if a solid modelling system is used. This paper presents a method for generating numerically-controlled milling machine tool paths directly from constructive solid geometry part representations. The algorithm requires less user interaction than APT boundary representation methods. A wide variety of parts may be machined using standard torus (bull) ended milling cutters. The algorithm is computationally efficient, and requires iteration only on portions of the part where gouging may occur.