High-speed hard milling on the cutting edge will produce a high temperature, if the use of cooling liquid cooling and lubrication, the tool will lead to a drastic temperature mutation load, resulting in cemented carbide body tissue micro-cracks. Thus, the tool will fail prematurely. Thus, high-speed hard milling should not be used when the cooling liquid cooling and lubrication should be used dry and hard machining. But given the hard milling when cutting temperature with the hardness of the workpiece and the cutting speed increases, so in the hardness of the workpiece is not very high, at high speed hard milling also consider using MQL. When the high hardness of the workpiece, which can cause MQL carbide cutting tools have a strong thermal shock loads. Thus, for such high-speed hard milling should blowing cold air compression chips, to avoid thermal shock loading, tool life generally increased by 20 to 30%. In addition, especially for six blade cutter, using compressed air to blow debris can be wrapped to avoid processing chips.