The emergence of new technologies for high-speed machining tool performance also put forward higher requirements, these tools at high spindle speeds and high feed rates of processing conditions should remain stable cutting performance. Today, high-speed / high-hard milling areas, ordinary carbide cutting tools market space is getting smaller and smaller, although this type of tool is not completely out of the market, but the market is no longer popular advanced machine tools using a 20 or even 10 years ago years ago designed carbide cutting tools, because the market has completely changed. In the field of hard milling tool geometry parameters must be designed to meet both rigidity and precision requirements.
     For the whole circular tool, the tool rigidity main indicators reflect a core diameter sizes. Standard core diameter end mill for 50% diameter. Due to the higher of hard milling cutter rigid requirements, the use of the core diameter size accounted for 60% to 70% of the diameter at the expense of some chip flutes space in return get a knife body mass increases, the rigidity increase in provides better support for cutting edge milling hardened materials. Because of the cutting depth rarely exceeds 10% of the tool diameter, therefore reducing the capacity of flute space does not become a big problem.
     In the three-dimensional milling, the tool "accuracy" refers generally to "radial accuracy." Radial ball end mill can reflect the precision mold cavity and core processing will take after the extent of manual grinding. Quality ball end mill should be tested once every 10 ° radial accuracy, and precision of detection ordinary end mills are often much more relaxed, the result is an error when processing tool is transferred to the workpiece, an increase of additional manual grinding work.