Together with technological development, reduction of manufacturing costs is urgent in the die-cast mold market, due to compeLition at home and abroad. The technology has been shifting from electrodischarge machining to less expensive direct cutting processes. One means of furthering this shift to direct cutting is to increase the direct cutting range by lengthening the tool overhang. This study describes a method of applying quality engineering to find conditions permitting the overhang length to be increased, and considers the tool chipping that resulted from the lengthened overhang. As a result of this study,optimal conditions were found that enabled the overhang of a 12-mm diameter ball end mill to be increased to about L/D=10, and the cause of chipping was determined.
