Computer aided manufacturing of high precision hobs

Abstract

The precision of hobs mostly depends on the relief grinding and sharpening of hob teeth. The more difficult and sensitive operation is the relief grinding. Upon repeated resharpening the precision of the hob would be lost if the relief grinding of hob teeth was not carried out correctly. To maintain the precision possessed by the new hob, the relief grinding must ensure an unchanged profile angle along the teeth. This requirement can be achieved only by correct set up of the grinding machine. In this paper a method is presented to calculate the optimal values of rotational and tilt angles of the grinding wheel axis. The optimal values of these two angles are determined by the condition that the profile angle of teeth is the same for the new hob and for the used hob resharpened to the end of the usable part of teeth. By using the corresponding computer program the influence of hob and grinding wheel parameters on machine set up is investigated and the results obtained are discussed in this paper. This method of computer aided manufacturing of hobs has been applied successfully to the products of the company Jugoalat in Novi Sad.