高能率ホブ切りにおける再コーティングホブの効果

抄録

It is well known that the life of TiN-coated hob becomes tremendously longer than that of non-coated hob. But even a TiN-coated hob, its rake surface must be must be resharpened when it was womn out. And then TiN-coating on rake surface is removed but only on flank surface. And TiN-coating on flank surface is still effective to decrease the flank wear. On the contrary, crater wear on rake surface of TiN-coated hob increases, same as that of non-coated hob. So, in high efficiency hobbing, the life of hob seriously depends on the crater wear. Here, the authors have clarified the effect of re-coated hob in case of high efficiency hobbing of the comparatively small module gears with TiN-coated and multi-start hobs that fre ofen used for motorcycles and automobiles. as a TiN-coated hob was used and then resharpened, only the rake surface can be re-coated with TiN layer and after that, it can attain the same cutting performance as a new TiN-hob. The most effective method to increase the life of TiN-coated hod and its cutting performance is to re-coat it after resharpened.