The Damage of Carbide Hobs

Abstract

With the development of the carbide hobber and improvement in the manufacturing of the carbide hob, carbide hobbing has found extensive use in industry. For example, annealed gear blanks which are often used in mass production can be carbide-hobbed without trouble. In addition, it can also be adopted to hob gear blanks of heat-treated or hard materials which have thus far proven to be difficult to cut using high-speed steel hobs. However, in the case of carbide hobbing for gear blanks which have been heat-treated, damage from chipping or thermal cracks, seen as an increase of relief wear, will occur during the lifetime of carbide hob because of unsuitable cutting conditions. In this paper, the authors have investigated the cause of and countermeasures against damage by systematically classifying the shapes of damage on the cutting edge in carbide hobbing.