As can be seen from the results with long-necked type vertical milling skd11 cold work die steel (60hrc), the ball end mill of peripheral cutting edge of great damage; and deep processing epoch rounded end mill no damage, only uniform wear. Can be inferred, due to the large contact length of the cutting edge ball end mill, thus cutting resistance is also large, high cutting speed peripheral cutting edge easily damaged. This is the same as in Example ①, rounded end mill has obvious advantages. Under the same processing conditions by a rounded end mill tools and Hitachi rounded end mill compared to other companies can be seen, other companies produce rounded end mills because there is no use of an inverted cone design, high over 60hrc hardness materials processing effect is not ideal. A new generation of deep rounded end mill cutting tool because Hitachi anticline-like shape with a unique design, peripheral cutting edge of the point-contact cutting, even in working with straight Qiefa Jia high hardness materials, the cutting resistance is small, and the processing of state stability. The epoch of deep cutting rounded end mill processing examples shows that excellent performance of the tool, especially when a clear advantage for high hardness materials cutting deep. In short, give full play to the role of a rounded end mills can be heat-treated hardened materials for direct machining grooves, because the process is shortened, can significantly reduce processing costs. Experimental results show that the use of rounded end milling efficiency can be increased more than five-fold, while the fees can be reduced by 35%.