Hard fine machining of gears through continuous generating grinding

The current developments in gear manufacturing are characterized by making even higher demands on load capacity, quiet running and life time of the gears. At the same time the workpiece dimensions as well as the production costs have to be constantly reduced. This leads to an enhancement of the gear quality aimed at increasing the load capacity and minimizing the running noises. After cutting the gear profile by means of hobbing or shaving, a heat treatment of the workpiece is carried out with the target of increasing the wear resistance of the tooth flanks. A hard fine machining is inevitable in order to remove the material distortions which come into existence during the heat treatment and to fulfil the dimensional and quality requirements. Among the existing processes for hard fine machining of gears, generating grinding by means of cylindrical grinding worms shows the highest potential in batch production because of the high material removal performance that can be reached. This contribution describes the characteristics of generating grinding as well as the technology for dressing both corundum and CBN grinding worms. The paper shows the process potential as well as a model for calculating the specific material removal rate along the tooth flanks in dependence of different process parameters.