Research On The Helical Milling Specialized Tool For Aeronautical Hard-machining Materials

As the development of aircraft digital assembly and the application of new aeronautical hard-machining materials such as titanium alloy and carbon fiber reinforce plastic (CFRP), traditional drilling technology can’t meet the requirement of hole-making increasingly. Helical milling, a new hole-making technology, shows great advantages compared with traditional drilling, especially for the titanium alloy and CFRP, and has been put into application in foreign aircraft assembly. However, the related technology is blocked for China. So far, the domestic research of helical milling mainly use traditional end mill. However, there are many problems when helical milling with end mill. Therefore, it’s necessary to develop the specialized tool for helical milling independently.After analyzing the tool’s movement of helical milling, the mathmatical description of tool’s movement track and cutting speed is established and the problems with end mill are pointed out. A new specialized tool for helical milling with distributed multi-point front cutting edge is designed based on free cutting and chip-splitting mechanism, which uses the design of multifact drill as reference to solve the problems of end mill. The cutting edge movement track description of the specialized tool and end mill is used to analyzing the chip-splitting result, and the simulation of chip is used to analyzing the chip shape and the different function of front and peripheral cutting edges by comparison with end mill.The helical milling experiments of aluminum alloy, titanium alloy and CFRP are used to testify the chip-splitting result, the hole quality and the service life of the specialized tool. At the same time, the burr control function of specialized tool’s front cutting edge is explained by the cap formation process of titanium alloy hole exit.At last, combining the related experiments, theoretical analysys result and tool’s improvement process, the optimization of tool’s geometry such as rake angle, center cutting edge and the distribution of front cutting edge points is present.