The manufacture in series of the SPIROMATIC bevel gear generator began in 1948. These generators have been supplied in appreciable numbers to various countries. The Oerlikon gear cutting process derives from systems originated about forty years ago, such as continuous indexing, face-type milling cutters with inserted blades, and constant tooth depth. The gear tooth curves thus obtained are portions of extended epicycloids. The processing operation from blank to gear is performed in one single cutting, divided into a first phase, during which the tooth spaces are grooved in the course of a plunge-cut motion, and a second, subsequent phase, during which the tooth profiles are generated through a rolling motion. New standard cutters with a wide working range ensure remarkably short production times. Owing to the mathematical simplicity of the process, to the ready and practical method for obtaining localised tooth bearing (crown), calculations are reduced to a minimum, and correct gears are produced from the start without any trials.
