Abstract
In late years, dry bobbing without the cutting oil is adopted for consideration for a global environment and the work environment, and a cost cut. This paper presents the experimental results of dry bobbing where four hobs with different coating film were tested. Under the cutting conditions, each hob demonstrates a considerably satisfactory performance although the TiAlN coating seems to be somewhat more favorable than the others, i.e. TiN, TiSiN and AlCrSiN. Another meaningful result suggests that excellent tool life may be expected for higher cutting speed with these hobs.
