Influence of a Two-Cut-Strategy on Tool Wear in Gear Hobbing

This report addresses both the empirical and theoretical analysis of a two-cut strategy for gear hobbing with conventional hobs. Tool life and wear behavior of PM-HSS S390 tools are analyzed in fly-cutting trials when machining 20MnCr5 case-hardening steel. By varying the axial feed rate in the first and the second cut, the influence of the interaction between both cuts on the tool wear is investigated. The results are compared to wear measurements from trials conducted with a one-cut strategy. It was shown that at the underlying test conditions, the average proportion of wear in the second cut was about 4%. For a better understanding of the interaction between the two cuts, load collectives were formed based on characteristic chip values calculated with SPARTApro. The collectives were evaluated with regard to the tool life.