Abstract
This study deals with the technology of high speed end milling of hardened steel by a high speed milling machine with an air spindle. Nowadays, for machining of dies and molds high speed end milling method has been developed to improve machining efficiency. In the previous paper, it was shown that use of a high speed machine enables stable machining to be carried out. But, still some problems to be solved for high efficient end milling of metal molds and dies, which have deep cavities. In this paper, stability of high speed end milling of hardened steel in case of long overhang are discussed. The main results are as follows ; (1) The stable range of high speed end milling in case of long overhang becomes narrower than that under standard conditions. (2) The proposed easy testing method of stability discrimination is effective for selecting stable cutting conditions in case of long overhang. (3) Both high efficiency and accurate surface without need of polishing were realized as a result of applying our method to high speed end milling of the crankshaft forging die.
